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182 Cards in this Set
- Front
- Back
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Peptidoglycan - function & composition
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Gives rigid support & protects against osmotic pressure.
Sugar backbone with peptide side chains linked by transpeptidase |
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Cell wall - function & composition
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In gram positive bacteria, serves as major surface antigen.
Contains peptidoglycan for support, & lipotechoic acid which induces TNF & IL-1 |
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Outer membrane - function & composition
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In gram negative bacteria is the major surface antigen.
Contains endotoxin/lipopolysaccharide, which induces TNF & IL-1. LPS contains O polysaccharide, which is the antigen. |
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Periplasm - function & composition
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In gram negative bacteria, space between cytoplasmic membrane & outer membrane.
Contains hydrolytic enzymes (beta-lactamases) |
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Spores - function, composition, destruction
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Resistant to dehydration, heat, & chemicals.
Have a keratin-like coat, contain dipicolinic acid & peptidoglycan. Must autoclave to kill spores - steam at 121 C for 15 min; or 5% hypochlorite |
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Endotoxin - source, function, antigenicity, heat-stability
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AKA Lipopolysaccharide (LPS). Found in outer cell membrane of most gram-negative bacteria. Not secreted from cell, Genes located on bacterial chromosome.
Low toxicity, induces TNF & IL-1 causing fever & shock. Poorly antigenic Heat stable at 100 C for 1 hour. |
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Exotoxin - source, function, antigenicity, heat-stability
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Found in some gram positive & gram negative bacteria. Polypeptide, secreted from cell. Genes located on plasmid or bacteriophage.
High toxicity. Induces high-titer antibodies - antitoxins. Toxoids can be used as vaccines. Destroyed rapidly at 60C |
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Lag phase
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metabolic activity without division
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Exponential/log phase
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Rapid cell division, production of peptidoglycan
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Stationary phase
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Slowed growth due to nutrient depletion. Spore formation
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Death phase
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Prolonged nutrient depletion and buildup of waste products leads to death
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What is transformation? What bacteria can do it?
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Ability to take up naked DNA from environment (AKA competency).
Feature of S pneumoniae, H influenzae type B, & Neisseria. |
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What occurs in a F+ x F- mating? What are each of those? What is transferred?
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F+ cell contains the F+ plasmid, contains genes required for sex pilus & conjugation. F- bacteria don't contain the plasmid.
Plasmid is replicated & transferred through the pilus from the F+ to the F-cell, with no transfer of chromosomal genes. |
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What occurs in a Hfr x F- mating? What is a Hfr? What is transferred?
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Hfr = high frequency recombination. Occurs when a F+ plasmid is incorporated into bacterial chromosomal DNA.
Replication of the incorporated plasmid DNA can include some flanking chromosomal DNA - when transferred to F- plasmid, will include both plasmid & chromosomal genes. |
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Mechanism of transposition? What is transferred?
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Transposons can jump from one location to another, transferring genes between plasmids/chromosomes. When they excise they can take some flanking chromosomal DNA, which can be incorporated into a plasmid and later transferred to another bacteria
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Mechanism of generalized transduction
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A "packaging" event. Occurs when a lytic phage infects a bacterium, leading to cleavage of bacterial DNA. Parts of the bacterial chromosomal DNA may become packaged in the viral capsid. When the phage infects another bacterium it can transfer these genes.
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Mechanism of specialized transduction
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An "excision" event. Occurs when a lysogenic phage infects a bacterium, and viral DNA incorporates into the bacterial chromosome. When the viral DNA is excised it may take some flanking bacterial genes with it. The DNA is packaged into the viral capsid and can infect another bacterium.
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Which 5 bacterial toxins are encoded in a lysogenic phage?
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Shiga-like toxin, Botulinum toxin, Cholera toxin, Diptheria toxin, Erythrogenic toxin of S pyogenes
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Staphylococcus aureus - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) cocci in clusters; beta-hemolysis; coagulase positive; catalase positive; golden colonies on mannitol salt agar; ferment mannose
VFs: polysaccharide capsule/slime layer; cytotoxins (alpha, beta, gamma); PV leukocidin in CA-MRSA; Protein A (binds Fc of IgG); TSST (superantigen); preformed heat-stable enterotoxin; exfoliative toxin Transmission: normal flora of nose & skin, trans by skin-to-skin Diseases: Skin infections; abscesses' post-influenzal pneumonia; Toxic shock syndrome; scalded skin syndrome; rapid-onset foot poisoning; MRSA; acute bacterial endocarditis; osteomyelitis Treatment: -Cillins; Vancomycin for CA-MRSA |
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Toxic shock syndrome - etiology, presentation
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Infection with S. aureus or S. pyogenes. TSST is a superantigen that binds MHC II & T cell receptor -> polyclonal T cell activation.
Fever, vomiting, rash, desquamation, shock, end-organ failure. Seen in tampon users. |
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Stapylococcus epidermidis - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) cocci in clusters; catalase (+); coagulase (-); novobiocin sensitive; white non-hemolytic colonies
VFs: forms adherent biofilms; antibiotic resistance Trans: Normal flora of skin Diseases: Infects prosthetic devices & IV catheters Treatment: Vancomycin +/- Rifampin/Gentamicin |
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Streptococcus pneumoniae - identifiers, virulence factors, diseases
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Identifiers: Lancet-shaped gram (+) diplococci; encapsulated; alpha-hemolytic; bile-soluble; optochin sensitive; rusty sputum; (+) Quellung
VFs: IgA protease; pneumolysin; capsule Diseases: Most common cause of meningitis, otitis media, pneumonia (lobar), sinusitis; sepsis in sickle cell anemia & splenectomy |
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Viridans streptococci - identifiers, transmission, diseases
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Identifiers: Gram (+) cocci in chains; alpha-hemolytic; optochin resistant
Transmission: normal flora of oropharynx Diseases: dental caries; subacute bacterial endocarditis (S. sanguis) |
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Streptococcus pyogenes (GAS) - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) cocci in chains; beta-hemolytic; bacitracin sensitive; ASO titer; Anti-DNase B titer
VFs: Hyaluronidase, Streptolysin O (O2- labile) & S (O2-stable); Streptokinase; DNase; erythrogenic toxin Trans: Normal flora of skin & pharnyx Diseases: Pyogenic - pharyngitis, cellulitis, impetigo; Toxigenic - scarlet fever, TSS, necrotizing fasciitis; immunologic - rheumatic fever (following pharyngitis), glomerulonephritis (following impetigo or pharyngitis) Tx: Penicillin |
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Streptococcus agalactiae (GBS) - identifiers, transmission, diseases, treatment
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Identifiers: bacitracin resistant; beta-hemolytic; CAMP factor; hippurate test (+)
Trans: colonizes vagina- trans via passage through birth canal Diseases: Neonatal pneumonia/meningitis/sepsis Tx: Penicillin or vancomycin; screen pregnant women at 35-37 wks -> if (+) given intrapartum penicillin |
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Enterococci - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Grow in 6.5% NaCl & bile; BEA (+); variable hemolysis
VFs: Penicillin-resistant; some vancomycin-resistant Trans: normal colonic flora Diseases: UTI; biliary tract infections; subacute endocarditis Tx: VRE -> Linezolid, Streptogramins |
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Streptococcus bovis - identifiers, transmission, diseases
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Identifiers: BEA (+); no growth in 6.5% NaCl
Trans: Colonizes gut Diseases: bacteremia; subacute endocarditis in pts with carcinoma of the colon |
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Corynebacterium diptheriae - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; club-shaped; black colonies on crystal-tellurite agar; catalase (+); Loeffler's medium; cytoplasmic metachromic granules with methylene blue; Elek's test for toxin
VFs: A-B exotoxin ADP-ribosylates EF-2 (encoded by beta-phage) Trans: aerosol inhalation or skin contact Diseases: Diptheria - Pseudomembranous pharyngitis with LAD , myocarditis, & arrythmias Tx: Toxoid vaccine for prevention |
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Clostridium tetani - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; spore-forming; obligate anaerobe
VFs: A-B exotoxin tetanospasmin blocks glycine & GABA release from Renshaw cells in SC Trans: deep cut, nail puncture, improper cut of umbilical cord Diseases: Tetanus - spastic paralysis, trismus, risus sardonicus Treatment: Tetanus anti-globulin; toxoid for prevention |
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Clostridium botulinum - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; spore-forming; obligate anaerobe
VFs: Preformed heat-labile toxin inhibits ACh release at NMJ Trans: adults - ingestion of preformed toxin; babies - ingestion of spores in honey; canned foods Diseases: Botulism - flaccid paralysis, mydriasis, skeletal m weakness, respiratory compromise, worsening of acute-angle glaucoma Treatment: Antitoxin |
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What is botulinum toxin used for?
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To treat focal dystonias, achalasia, & spasms
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Clostridium perfringens - identifiers, virulence factors, transmission, diseases
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Identifiers: Gram (+) bacilli; spore-forming; obligate anaerobe; boxcar shaped; double-zone of hemolysis
VFs: alpha-toxin (lethicinase); beta-toxin; enterotoxin Trans: Trauma/wounds, ingestion of reheated meats Diseases: Gas gangrene & myonecrosis (alpha); late-onset foot poisoning (entero); necrotizing enteritis (beta) |
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Clostridium difficile - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; spore-forming; obligate anaerobe; toxin detection in stool
VFs: Toxin A - enterotoxin, binds at brush border of gut & attracts granulocytes; Toxin B - cytotoxin Trans: secondary to antibiotic use Diseases: Pseudomembranous colitis Treatment: Metronidazole or oral Vancomycin |
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Bacillus anthracis - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; spore-forming; D-glutamate capsule; non-motile
VFs: protective Ag (cell-binding), edema factor (AC), lethal factor (protease) Diseases: Cutaneous anthrax - spores inoculated into subcutaneous tissue, painless black eschar -> bacteremia; Pulmonary - inhalation of spores from animal products, flu-like sx rapidly progress to fever, pulmonary hemorrhage, hemorrhagic mediastinitis, shock, widened mediastinum on X-ray; GI - n/v, bloody diarrhea Tx: Ciprofloxacin |
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Bacillus cereus - identifiers, virulence factors, transmission, diseases
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Identifiers: Gram (+) bacilli; spore-forming
VFs: Heat-stable enterotoxin (emesis), heat-labile enterotoxin (activates AC, causes diarrhea), cereulide - preformed toxin Trans: ingesting spores in reheated rice & pasta DIseases: Food poisoning - Emetic type w/i 1-5 hrs, diarrheal w/i 8-18 hours |
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Listeria monocytogenes - identifiers, transmission, diseases, treatment
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Identifiers: Gram (+) bacilli; facultative intracellular; beta-hemolytic; 'actin rockets'; cold-enhanced growth at 4 C
Trans: transplacental; vaginal; ingestion of unpasterized milk/cheese Diseases: Amnionitis, septicemia, & spontaneous abortion in pregnant; granulomatosis infantiseptica; neonatal meningitis; meningitis in immunocompromised; mild gastroenteritis Tx: Ampicillin |
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Actinomyces israelii - identifiers, transmission, diseases, treatment
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Identifiers: Gram (+); filamentous; aerobe; NOT acid-fast; yellow sulfur granules
Trans: oral flora; dental surgery/trauma in oral cavity; IUD in women Diseases: oral/facial abscesses with draining sinus tracts Treatment; prolonged parenteral penicillin; surgical debridement |
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Nocardia asteroides - identifiers, transmission, diseases, treatment
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Identifiers: Gram (+); filamentous; aerobe; aerial hyphae; acid-fast
Trans: in soil; inhalation of aerosols; penetration of skin wounds; steroid users Diseases: Mycetoma; cellulitis; abscesses in brain & kidney; pulmonary infections in immunocompromised; cutaneous infections after trauma Tx: TMP-SMX |
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Mycobacterium tuberculosis - identifiers, Virulence factors, diseases, treatment
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Identifiers: acid-fast; gram (+) bacillus (stains poorly); mycolic acid in cell wall; PPD (+)
VFs: Cord factor - inhibits macrophage maturation, induces TNF-alpha, growth of serpentine cords; drug resistance Diseases: Tuberculosis - fever, night sweats, weight loss, hemoptysis. Can primary, secondary, miliary, or extrapulmonary. Treatment: Rifampin, INH, ethambutol, etc |
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Presentations of tuberculosis - Primary, Secondary, Miliary, Extrapulmonary
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Primary TB - Ghon focus in lower upper lobe/upper lower lobe. Organism phagocytosed by alveolar macrophages -> intracellular bacterial proliferation -> induces Th response 2-4 weeks after infection
Secondary TB - Reactivation -> cavitary lesion in upper lobes with caseating granulomas Miliary TB - lymphohematogeous dissemination -> caseating granulomas throughout organs, with seed-like gray lesions Extrapulmonary TB - CNS: parenchymal tuberculoma or meningitis, Pott's disease (spread to vertebral body), lymphadenitis, renal & GI symptoms |
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Mycobacterium kansasii - identifiers, diseases
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Identifiers: Acid-fast; gram (+) (stains poorly)
Diseases: symptoms similar to pulmonary TB |
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Mycobacterium avium-intracellulare - identifiers, diseases, treatment
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Identifiers: Acid-fast; gram (+) (stains poorly)
Diseases: disseminated disease in AIDS Treatment: Azithromycin; resistant to many drugs |
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Mycobacterium leprae - identifiers, transmission, disease
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Identifiers: Gram (+) bacillus; acid-fast; can't grow in vitro; prefers cool temps; lepromin test
Trans: skin contact, armadillo reservoir in US Disease: Leprosy. Infects skin & superficial nerves -> glove & stocking loss of sensation Treatment: Dapsone + Rifampin for 6 mos for tuberculoid; Dapsone, Rifampin, + Clofazimine for 2-5 yrs for lepromatous |
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Lepromatous vs Tuberculoid leprosy
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Lepromatous: due to low cell-mediated immunity & a Th2 humoral response; diffuse skin involvement with leonine faces; communicable; lepromin test (-)
Tuberculoid: due to high-cell mediated immunity with a Th1 response; few hypoesthetic hairless plaques; lepromin test (+) |
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What reaction can occur during treatment for leprosy? How is that treated?
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Erythema nosodum leprosum. Treated with thalidomide
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What is special about MacConkey's agar, and what bacteria grow on it?
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Lactose-fermenting bacteria grow pink colonies
Klebsiella, E. coli, Enterobacter, Serratia |
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EMB agar
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Lactose fermenters grow purple/black colonies. E coli grows purple colonies with a green sheen
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What drugs are gram (-) bacteria resistant to?
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Penicillin G & Vancomycin - due to outer membrane
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Neisseria gonorrhoeae - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: gram (-) diplococcus; ferments glucose; oxidase (+); within PMNs; doesn't ferment maltose; growth on chocolate agar/Thayer-Martin medium
VFs: IgA protease; pili with rapid antigenic variation Trans: sexually Diseases: Gonorrhea; septic arthritis; neonatal conjunctivitis; PID; Fitz-Hugh-Curtis syndrome Tx: Ceftriaxone (+ azithromycin/doxycycline) for possible chlamydia coinfection; no vaccine |
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Neisseria meningitidis - identifiers, transmission, diseases, treatment
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Identifiers: gram (-) diplococcus; ferments glucose + maltose; oxidase (+); polysaccharide capsule; C5-C9 deficiency; growth on chocolate agar
Trans: Respiratory & oral secretions; colonizes nasopharynx -> invades mucosal epithelium -> bloodstream -> choroid plexus -> BBB Diseases: Meningococcemia; meningitis; Waterhouse-Friedrichsen syndrome (DIC + bilateral adrenal failure) Tx: Ceftriaxone or Penicillin G; Prophylaxis with Rifampin/Ciprofloxacin/Ceftriaxone |
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Haemophilus influenzae - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (-) coccobacillus; growth on chocolate agar; requires V (NAD+) & X (hematin) for growth; growth with S. aureus (provides V)
VFs: capsule (type B esp); IgA protease Trans: via aerosols Diseases: epiglottis in children; meningitis; otitis media; pneumonia Tx: Ceftriaxone for meningitis; prophylaxis with Rifampin; vaccine for type B |
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H influenzae vaccine
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Contains type B capsular polysaccharide (polyribosylribitol phosphate) conjugated to diphtheria toxoid/other protein. Given at 2-18 months old.
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Legionella pneumophila - identifiers, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; gram stains poorly; silver stain; grows on charcoal yeast extract agar (CYEA) with iron + cysteine; antigen in urine; sputum stain showing many PMNs with no organisms; hyponatremia
Trans: aerosol from water source Diseases: Legionnaires' disease - atypical pneumonia; Pontiac fever - mild flu-like sx Tx: Macrolide or quinolone |
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Pseudomonas aeruginosa - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; aerobe; non-lactose fermenting; oxidase (+); pyocanin (blue/green pigment); grape-like odor; motile
VFs: endotoxin; exotoxin A (inactivates EF-2); chromosomally mediated resistance due to mutation in porin protein Trans: water source; immunosuppressed pts Diseases: Wound & burn infections; pneumonia (in CF); sepsis; external otitis; UTI w/ indwelling catheters; Tricuspid valve endocarditis in IVDU; diabetic osteomyelitis; hot tub folliculitis; malignant otitis externa in diabetics; ecythymia gangrenosum Tx: Aminoglycoside + anti-pseudomonal penicillin (piperacillin); 3rd & 4th gen cephalosporins; Quinolones; Aztreonam/Imipenem |
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Escherichia coli virulence factors
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Fimbriae - adhesion to uroepithelium in UTIs
Heat-stable (activates AC) & heat-labile (GC) enterotoxins - fluid & electrolyte secretion from intestinal epithelium -> watery diarrhea LPS - bacteremia & septic shock K1 capsular polysaccharide - prevents phagocytosis & complement-mediated lysis - neonatal meningitis Verotoxin (shiga-like) - inactivates 60S - dysentery |
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Enteroinvasive E. coli - pathogenesis & clinical manifestations
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Invades intestinal mucosa -> necrosis & inflammation. No toxins produced.
Causes dysentery. |
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Enterotoxigenic E. coli - pathogenesis & clinical manifestations
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Produces heat-labile & heat-stable enterotoxins. No inflammation or invasion.
Causes traveler's diarrhea - increased secretion of Cl-, decreased absorption of Cl- & Na+ |
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Enteropathogenic E. coli - pathogenesis & clinical manifestations
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Adheres to apical surface & flattens villi, preventing absorption. no toxins produced.
Watery diarrhea in children. |
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Enterohemorrhagic E. coli - pathogenesis & clinical manifestations
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Produces Shiga-like/verotoxin. Associated with eating undercooked beef.
Causes hemolytic-uremic syndrome - microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure; Dysentery; Hemorrhagic colitis |
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Klebsiella pneumoniae - identifiers, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; fast lactose fermenter; mucoid colonies; abundant polysaccharide capsule; currant jelly sputum
Trans: Intestinal flora Diseases: Lobar/aspiration pneumonia in alcoholics/diabetics; nosocomial UTIs; abscess in lungs & liver Treatment - 3rd gen cephalosporin |
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Salmonella enteritidis - identifiers, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; oxidase (-); lactose (-); H2S (+); motile with flagella; capsule; intracellular growth
Trans: eating dairy & raw eggs; many animal reservoirs Diseases: Invades intestinal mucosa causing watery (or bloody) diarrhea; can disseminate hematogenously Tx: antibiotics prolong symptoms and carrier state |
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Shigella flexneri & sonnei - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; oxidase (-); H2S (-); lactose (-); non-motile; Type III secretion system; gas (-)
VFs: Shiga-toxin - A-B exotoxin, inactivates 60S Trans: fingers, feces, food, flies, fomites; human & primate reservoirs; spreads cell-to-cell. S. sonnei in industrialized regions, S. flexneri in developing countries; predilection for gay men & adults in nursing facilities Tx: antibiotics shorten excretion of organism in feces Diseases: bloody diarrhea |
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Salmonella paratyphi - identifiers, transmission, diseases, treatment
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Identifiers: Gram (-) bacillus; oxidase (-); lactose (-); H2S (+); motile with flagella
Trans: endemic in Asia, Africa, & Latin America; only in humans Diseases: typhoid fever - rose spots on abdomen, HSM, fever, headache, diarrhea; can remain in GB causing carrier state; hemorrhagic enteritis with bowel perforation Tx: recovery confers immunity |
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Campylobacter jejuni - identifiers, transmission, diseases
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Identifiers: Gram (-); comma-shaped; oxidase (+); grows at 42 C
Trans: fecal-oral via poultry, meat, unpasteurized milk; direct contact with infected animals; penetrates via transporters on enterocytes and via phagocytosis by M cells in Peyer's patches Diseases: bloody diarrhea; Guillain-Barre syndrome (ascending muscle weakness & paralysis); reactive arthritis |
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Vibrio cholerae - identifiers, virulence factors, transmission, diseases, treatment
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Identifiers: Gram (-); comma-shaped; oxidase (+); growth in alkaline media
VFs: cholera toxin permanently activates Gs -> increased cAMP Trans: endemic to developing countries Diseases: rice-water diarrhea Tx: prompt rehydration |
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Vibrio vulnificus - identifiers, transmission, diseases,
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Identifiers: Gram (-); comma-shaped; oxidase (+)
Trans: eating raw shellfish Diseases: septicemia; wound infections; cellulitis/fasciitis/myositis; fluid-filled blisters that progress to muscle necrosis |
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Yersinia enterocolitica - identifiers, transmission, diseases
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Identifiers: Gram (-) coccobacillus
Trans: pet feces; contaminated milk or pork Diseases: mesenteric adenitis that can mimic Crohn's or appendicits (pseudoappendicitis); mini-epidemics of pediatric diarrhea; febrile diarrhea in children |
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Helicobacter pylori - identifiers, diseases, treatment
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Identifiers: Gram (-) curved bacillus; oxidase (+); urease (+); creates alkaline environment
Disease: Gastritis; duodenal ulcers; risk factor for peptic ulcer, gastric adenocarcinoma, & lymphoma Tx: Triple therapy - PPI + Clarithromycin + Amoxicillin/Metronidazole |
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Urease breath test
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Pt consumes 13C-labeled urea. Their breath is monitored for 13C labeled CO2, which indicates urease from H pylori in stomach
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How are spirochetes visualized?
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With dark-field microscopy
Borrelia is large enough to be viewed in LM with Wright's or Giemsa stain |
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Leptospira interrogans - identifiers, transmission, diseases
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Identifiers: Spirochete
Trans: Found in contaminated water with animal urine; in surfers & tropics Diseases: Leptospirosis - flu-like sx, jaundice, photophobia with conjunctivitis; Weil's disease - icterohemorrhagic leptospirosis with liver & kidney dysfunction, fever, hemorrhage, & anemia |
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Borrelia burgdoferi - identifiers, transmission, diseases, treatment
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Identifiers: Spirochete; visualized with LM
Trans: transmitted by deer tick Ixodes; mouse reservoir; in NE US Disease: Lyme Disease - erythema chronicum migrans, flu-like sx, Bell's palsy, AV nodal block, chronic monoarthritis, migratory polyarthritis, encephalopathy, polyneuropathy Tx: Doxycyline; Ceftriaxone |
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Ixodes is a vector for which organisms?
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Borrelia burgdoferi & Babesia microti
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Treponema pallidum - identifiers, transmission, diseases, treatment
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Identifiers: Spirochete; VDRL + RPR; FTA-ABS + MHA-TP; motile via flagella or axial filament; dark-fieldmicroscopy showing treponemes in chancre/condyloma lata; Jarisch-Herxheimer reaction
Trans: sexual, placental Disease: Syphilis Tx: Penicillin G |
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Features of primary, secondary, & tertiary syphilis?
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Primary - Localized, with painless chancre
Secondary - Disseminated. Constitutional sx, maculopapular rash on palms & soles, condylomata lata Tertiary - Gummas, aortitis, tabes dorsalis, Argyll-Robertson pupil, (+) Romberg, Charcoat joints, stroke w/o HTN, ataxia. Spinal fluid shows (+) VDRL. |
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Features of congenital syphilis? When is it transmitted?
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Saber shins, saddle nose, CN VIII deafness, Hutchinsons' teeth, mulberry molars.
After 1st trimester |
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What is the VDRL test used for? What does it detect? What causes false positives?
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Used to diagnose syphilis. Detects beef cardiolipin.
False positives - Viral infections (mono, hepatitis), Drugs, Rheumatic fever, Lupus & leprosy |
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Jarisch-Herxheimer reaction
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Occurs after antibiotics are started, and killed spirochetes release pyrogens -> flu-like syndrome
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Bartonella henselae - disease & transmission
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Cat-scratch disease. I bet you can't guess how it's transmitted.
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Borrelia recurrentis - Identification, Virulence factors, transmission, disease
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Identification: Spirochete; seen with LM
VFs: variable surface antigen Trans: Louse Disease: Recurrent fever - raised red rash, fever, jaundice, hepatosplenomegaly |
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Brucella spp - transmission & disease
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Via unpasteurized dairy.
Causes brucellosis/undulant fever |
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Chlamydophila psittaci - transmission & disease
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Inhalation of dried feces from parrots/other birds. avian reservoir.
Causes Psittacosis - atypical pneumonia |
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Coxiella burnetti - transmission, disease, treatment
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Obligate intracellular; Tick feces & cattle placenta release spores that are inhaled as aerosols; no arthropod vector
Causes Q fever - pneumonia Treated with doxycycline |
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Erhlichia chafeensis - identification, transmission, disease, treatment
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Obligate intracellular; Monocytes with morula (berry-like inclusions) in cytoplasm
Via Lone Star tick Causes Erhlichiosis Treated with doxycyline |
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Francisella tularensis - identifiers, transmission & disease
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Facultative intracellular
Rabbits via tick bite or deer fly; handling animal carcasses; in hunters Causes tularemia - ulceroglandular fever with generalized lymphadenopathy |
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Pasteurella multocida - transmission & disease
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Via animal bites - cats, dogs
Causes acute cellulitis, osteomyelitis, draining cutaneous sinus tracts, lymphadenopathy, septic joints |
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Yersinia pestis - transmission, disease
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Via fleas; rat & prarie dog reservoirs; aerosol
causes PLAGUE, with buboes (inflamed, swollen LNs) |
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Gardnerella vaginalis - identifiers, transmission, disease, treatment
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ID: Pleiomorphic; gram-variable; bacillus; Clue cells on microscope
Trans: assc with sexual activity Disease: Vaginosis - gray vaginal discharge with fishy smell, nonpainful Tx: Metronidazole |
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Rickettsia rickettsii - identifiers, transmission, disease, treatment
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ID: obligate intracellular; need CoA & NAD+
Trans: broadly distributed in US Disease: Rocky Mountain Spotted Fever - rash starts at wrists & ankles and spreads to trunk, palms, & soles Tx: Doxycycline |
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Rickettsia typhi - identifiers, transmission, disease, treatment
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ID: obligate intracellular; needs CoA & NAD+
Trans: Fleas Disease: Endemic (murine) typhus - rash on trunk Tx: Doxycycline |
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Rickettsia prowazekii - identifiers, transmission, disease, treatment
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ID: obligate intracellular; needs CoA + NAD+
Trans: Human body louse Disease: Epidemic typhus - rash starts centrally and spreads out, sparing palms and soles Tx: Doxycycline |
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Anaplasma - identifiers, transmission, disease, treatment
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ID: obligate intracellular; granulocytes with morula in cytoplasm
Trans: tick Disease: Anaplasmosis Tx: doxycycline |
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What are the forms of Chlamydia?
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Elementary body - infectious form, enters cell via endocytosis, metabolically inactive
Reticulate body - replicates in cell by binary fission, form seen on tissue culture |
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Chlamydia trachomatis - identifiers, transmission, disease, treatment
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ID: Obligate intracellular; can't make ATP; cytoplasmic glycogen inclusions seen on Giemsa or flourescent antibody stained-smear & stain with iodine; cell wall lacks muramic acid
Trans: sexual; passage through birth canal; hand-to-eye; Disease: A, B, C - chronic follicular conjuctivitis -> blindness in Africa; D-K - Urethritis, PID, ectopic pregnancy, pneumonia, neonatal conjunctivitis; L1-L3 - Lymphogranuloma venereum Tx: Azithromycin or doxycyline; Tetracycline, erythromycin for LGV |
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Lymphogranuloma venereum - etiology & presentation
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Infection with C. trachomatis types L1-L3.
Initial papule heals, LNs enlarge & develop fistulas. May develop genital elephantiasis. Cell culture shows glycogen-containing inclusions. |
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Mycoplasma pneumoniae - identifiers, transmission, disease, treatment
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ID: no cell wall; not seen on gram stain; sterols in membrane; requires cholesterol to grow on artificial media; IgM cold agglutinins; Eaton's agar
Trans: aerosol - in military recruits, prisons, pts <30 Disease: Atypical pneumonia Tx: Macrolide or Fluoroquinolone |
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Histoplasma capsulatum - identifiers, transmission, disease, treatment
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ID: oval yeasts within macrophages; branching hyphae at 25C; yeast at body temp; not a true capsule
Trans: exposure to tuberculate macro/microconidia; bird/bat droppings, soil; Ohio & Mississippi river valleys Disease: Histoplasmosis. Pulmonary - similar to TB, with lung granulomas & calcifications, hilar LAD. Can disseminate to lungs, spleen, liver. Tx: Fluconazole/itraconazole for local infection; amphotericin B for systemic infection |
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Blastomyces dermatidis - identifiers, transmission, disease, treatment
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ID: branching hyphae at 25C; yeast at 37C; large round yeasts with doubly refractile wall & single broad-based bud on bx
Trans: In soil; in states east of Miss. river & in Central America Disease: Blastomycosis: inflammatory lung disease with granulomatous nodules, can disseminate to skin & bones Tx: Fluconazole/itraconazole for local infection; amphotericin B for systemic infection |
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Coccidiodes immitis - identifiers, transmission, disease, treatment
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ID: hyphae at 25C; bx at 37 C forms double-refractile thick-walled spherules filled with endospores
Trans: inhalation of spores; mold present in soil; in SW US & California Disease: Coccidiodomycosis - Pneumonia & meningitis, can disseminate to bone & skin; San Joaquin Valley Fever/erythema nodosum Tx: Fluconazole/itraconazole for local infection; amphotericin B for systemic infection |
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Paracoccidiodes brasiliensis - identifiers, transmission, disease, treatment
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ID: Budding yeast with captain's wheel appearance at 37C; multiple blastoconidia at 25C
Trans: In Latin & Central America Disease: Paracoccidiodomycosis: Mucucocutaneous form with chronic mucocutaneous/cutaneous ulcers that can progress to LNs & lungs; Pneumonia and/or calcifying lung mass Tx: Fluconazole/itraconazole for local infection; amphotericin B for systemic infection |
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Malassezia furfur - identifiers, transmission, disease, treatment
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ID: fungi with spaghetti & meatball appearance
Trans: in hot humid weather Disease: Tinea versicolor - localized in stratum corneum causing hypopigmented/hyperpigmented skin patches Tx: Topic miconazole, selenium sulfide |
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Microsporum, Trichopyton, & Epidermophyton - ID, disease
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ID: Dermatophytes; mold hyphae in KOH prep; not dimorphic
Disease: Dermatophytoses - tinea pedis (food), tinea cruris (groin), tinea corporis (ringworm), tinea capitis (head), tinea unguium (onchomycosis) |
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Candida albicans - identifiers, transmission, disease, treatment
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ID: dimorphic yeast; pseudohyphae and budding yeasts at 20C; germ tubes at 37C; (+) germ tube test in HIV pt
Trans: infections related to antibiotic use, neutropenia/immunosuppression/HIV, DM, corticosteroids Disease: Candidiasis - Superficial infections; Disseminated candidiasis in neutropenics, affecting esophagus, liver, heart, kidney; Oral/esophageal thrush in immunocompromised; vulvovaginitis; diaper rash; endocarditis in IVDU; chronic mucocutaneous candidiasis Tx: Topical azole for vulvovaginitis; Fluconazole/caspofungin for oral/esophageal candidiasis; Fluconazole/amphotericin B/caspofungin for systemic |
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Aspergillus fumigatus - identifiers, disease, treatment
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ID: septate hyphae with acute (45 deg) branching in V-shaped pattern; conidophore with with radiating chains of spores; aflatoxins; not dimorphic
Disease: Invasive aspergillosis in immunocompromised/neutropenics & chronic granulomatous disease -> hemoptysis & lung granulomas; Allergic bronchopulmonary aspergillosis with asthma or CF -> wheezing & migratory pulmonary infiltrates; Aspergillomas in lung cavities after TB infection Tx: Steroids for ABPA |
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Cryptococcus neoformans - identifiers, transmission, disease, treatment
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ID: heavily encapsulated yeast; wide capsular halos & unequal budding; stains with India ink & mucicarmine stain; Sabouraud's agar; not dimorphic; latex agglutination test detects polysaccharide capsular antigen
Trans: inhalation with hematogenous dissemination to meninges; in soil, pigeon droppings Disease: Cryptococcal meningitis in AIDs pts with soap bubble lesions in brain; cryptococcosis; pulmonary disease with granuloma formation Tx: Amphotericin B + flucytosine for meningitis |
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Mucor & Rhizopus - identifiers, transmission, disease, treatment
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ID: only as molds (true hyphae); irregular broad nonseptate hyphae branching at wide angles
Trans: in DKA; leukemia; proliferate in blood vessel walls when there is excess ketone/glucose & penetrate cribiform plate and enter brain; predilection for paranasal sinuses Disease: Murcomycosis - Rhinocerebral form with frontal lobe abscesses, headache, facial pain, black necrotic eschar on face Tx: Surgical debridement & amphotericin B |
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Pneumocystis jirovecii - identifiers, transmission, disease, treatment
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ID: originally classified as protozoan; disc-shaped yeasts on methenamine-silver stain
Trans: inhaled; predisposed by immunosuppression (AIDS pts) Disease: Pneumocystis pneumonia with diffuse bilateral CXR appearance; premature infants with respiratory distress Tx: TMP-SMX, Pentamidine, Dapsone; Start prophylaxis in HIV pt when CD4 < 200 |
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Sporothrix schenckii - identifiers, transmission, disease, treatment
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ID: dimorphic; cigar-shaped yeast; branching hyphae at 25C
Trans: lives on vegetation; spores traumatically introduced into skin; seen in gardener's due to thorns Disease: Sporotrichosis - local pustule/ulcer with nodules along draining lymphatics Tx: Itraconazole or Potassium iodide |
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Giardia lambia - identifiers, transmission, disease, treatment
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ID: trophozoites (with smiley face) or cysts in stool
Trans: cysts in water Disease: Giardiasis - bloating, flatulence, foul-smelling fatty diarrhea Tx: Metronidazole |
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Entamoeba histolytica - identifiers, transmission, disease, treatment
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ID: trophozoites with RBCs in the cytoplasm or cysts with multiple nuclei in stool; flask-shaped ulcer; anchovy paste exudate
Trans: Cysts in water; fecal-oral; intestinal colonization preceds infection of liver Disease: Amebiasis - dysentery, liver abscess, RUQ pain Tx: Metronidazole; Iodoquinol for asymptomatic cyst passers (luminal stages) |
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Cryptosporidium parvum - identifiers, transmission, disease, treatment
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ID: Acid-fast cysts in stool
Trans: Cysts in water Disease: Severe diarrhea in AIDS pts (CD4 < 200); mild diarrhea in immunocompetent Tx: Nitozoxanide in immunocompetent; prevent by filtering water |
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Toxoplasma gondii - identifiers, transmission, disease, treatment
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ID: obligate intracellular; IgM in newborn if acute infection
Trans: Cysts in meat or cat feces (cat = definitive host); crosses placenta; develops intracellularly in phagocytes -> brain, muscle, tissues to encyst & multiply Disease: brain abscesses in HIV pts with ring-enhancing lesions; congenital toxoplasmosis with chorioretinitis, hydrocephalus, intracranial calcifications Tx: Sulfadiazine + Pyrimethamine |
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Naegleria fowleri - identifiers, transmission, disease, treatment
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ID: Amoebas in spinal fluid
Trans: swimming in freshwater lakes; enters via cribiform plate Disease: rapidly fatal meningoencephalitis Tx: Amphotericin somewhat effective |
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Trypanosoma brucei gambiense & rhodesiense - identifiers, transmission, disease, treatment
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ID: trypanosomes on blood smear; antigenic variation
Trans: via Tsetse fly bite Disease: African sleeping sickness - enlarged LNs, recurring fever, somnolescence, coma Tx: Suramin for blood-borne disease; Melarsoprol for CNS penetration |
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Plasmodium (all) - identifiers, transmission, disease, treatment
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ID: trophozoite ring form; RBC schizont with merozoites
Trans: Anopheles mosquito Disease: Malaria - cyclical fever, headache, anemia, splenomegaly Tx: Chloroquine; Mefloquine for chloroquine-resistant; IV quinidine for life-threatening; Primaquine for hypnozoite forms |
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Plasmodium vivax/ovale - fever cycle & presentation
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Tertian malaria with 48-hr cyclical fevers
Has dormant hypnozite form in liver - Schuffer's dots |
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Plasmodium falciparum - fever cycle & presentation
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Malignant tertian malaria with irregular fever patterns
Parasitized RBCs occluide capillaries in brain (-> cerebral malaria), kidneys, lungs |
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Plasmodium malariae - fever cycle & presentation
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Quartan malaria with 72-hr cyclical fevers
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Babesia microti - identifiers, transmission, disease, treatment
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ID: ring form; maltese-cross
Trans: Ixodes tick; in NE US Disease: Babesiosis - fever, hemolytic anemia; severe disease with asplenia Tx: Atovaquone + azithromycin |
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Trypanosoma cruzi - identifiers, transmission, disease, treatment
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ID: trypanosome on blood smear
Trans: Reduviid bug, in South America Disease: Chagas diseaes - dilated cardiomyopathy, megacolon, megaesophagus Tx: Nifurtimox |
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Leishmania donovani - identifiers, transmission, disease, treatment
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ID: Macrophages containing amastigotes
Trans: Sandfly Disease: Visceral leishmaniasis/Kala-azar - spiking fevers, hepatosplenomegaly, pancytopenia Tx: Sodium stibogluconate |
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Trichimonas vaginalis - identifiers, transmission, disease, treatment
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ID: Motile trophozoites; can't form cysts
Trans: Sexual; cannot exist outside of human body Disease: Vaginitis w/ foul-smelling greenish discharge Tx: Metronidazole for pt & partner |
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Enterobius vermicularis - identifiers, transmission, disease, treatment
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ID: pinworm; scotch tape test
Trans: food contaminated with eggs Disease: anal pruritis Tx: -bendazoles or pyrantel pamoate |
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Ascaris lumbricoides - identifiers, transmission, disease, treatment
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ID: eggs in feces; giant roundworm
Trans: fecal-oral Disease: intestinal infection & obstruction Tx: -bendazoles or pyrantel pamoate |
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Strongyloides stercoralis - transmission, disease, treatment
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Trans: larvae in soil penetrate skin
Disease: intestinal infection causing vomiting, diarrhea, anemia Tx: Ivermectin or albendazole |
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Ancylostoma duodenale & Necator americanus - identifiers, transmission, disease, treatment
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ID: hookworms
Trans: larvae penetrate skin Disease: Intestinal infection with microcytic anemia Tx: -bendazoles or pyrantel pamoate |
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Dracunculus medinesis - identifiers, transmission, disease, treatment
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ID: threadworm
Trans: drinking water Disease: skin inflammation & ulceration Tx: slow extraction of worm |
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Onchocerca volvulus - identifiers, transmission, disease, treatment
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ID: microfilariae
Trans: female blackfly bite Disease: River blindness with hyperpigmented skin Tx: Ivermectin |
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Loa loa - identifiers, transmission, disease, treatment
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ID: worm in conjunctiva
Trans: Deer fly, horse fly, mango fly Disease: Swelling in skin & conjunctiva Tx: Diethycarbamazine |
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Wuchereria bancrofti - transmission, disease, treatment
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Trans: Female mosquito
Disease: Elephantiasis due to lymphatic blockage, takes 9 mo - 1 yr for sx Tx: Diethylcarbamazepine |
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Toxocara canis - transmission, disease, treatment
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Trans: Food contaminated with eggs
Disease: Visceral larva migrans Tx: Al- or mebendazole |
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Taenia solium - transmission, disease, treatment
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Trans: ingestion of larvae encysted in undercooked pork, ingestion of eggs, autoinfection; in Mexico, Central America, Phillipines, SE Asia
Disease: Cystericosis - intestinal infection; Neurocystericosis - with cystic-space occuping lesions -> hydrocephalus, seizures, increased ICP Tx: Praziquentel for Cystericosis; -bendazole for neurocystericosis |
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Diphyllobothrium latum - identification, transmission, disease, treatment
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ID: operculated eggs or proglottids in feces
Trans: ingestion of larvae from raw freshwater fish; Great Lakes region; crustaceans = intermediate host Disease: Megaloblastic anemia & B12 deficiency Tx: Praziquantel |
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Enchinococcus granulosus - transmission, disease, treatment
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Trans: ingestion of eggs from dog feces
Disease: Unilocular cysts in liver -> can cause anaphylaxis if antigens released Tx: -Bendazoles; ingection with ethanol to kill cysts before removal |
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Schistoma hematobium - transmission, disease, treatment
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Trans: cercariae penetrate skin; snails are host; in North & Sub-Saharan Africa, Middle East
Disease: Urinary Schistosomiasis - terminal hematuria, dysuria, frequent urination; hydronephrosis, pyelonephritis, squamous cell carcinoma of the bladder Tx: Praziquantel |
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Schistoma mansoni & japonicum- transmission, disease, treatment
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Trans: cercariae penetrate skin; snails are host; mansoni in Sub-Saharan Africa, Middle East, South America, Caribbean; japonicum in Asia
Disease: Intestinal schistomiasis - diarrhea & abdominal pain, intestinal ulceration, iron deficiency anemia; Hepatic schistomiasis - hepatosplenomegaly, periportal fibrosis, portal hypertension, liver & spleen granulomas Tx: Praziquantel |
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Clonorchis sinensis - identification, transmission, disease, treatment
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ID: Liver fluke
Trans: Undercooked fish Disease: Biliary tract inflammation/obstruction, pigmented gallstones, cholangiocarcinoma, pancreatic duct obstruction Tx: Praziquantel |
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Paragonimus westermani - identification, transmission, disease, treatment
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ID: lung fluke
Trans: Undercooked crab meat Disease: Lung inflammation & secondary bacterial infection, hemoptysis Tx: Praziquantel |
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Mechanism of viral recombination
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exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology.
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Mechanism of viral reassortment? what is it's significance?
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High-frequency recombination where viruses with segmented genomes exchange those segments.
Causes influenza pandemics |
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mechanism of viral complementation
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Occurs when one virus that infects a cell has a mutation resulting in a nonfunctional protein, and a second, nonmutated virus complements the mutated one by making a functional protein that serves both viruses
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Mechanism of phenotypic mixing
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Occurs with simultaneous infection with 2 viruses, where the genome of 1 virus becomes partially/completely coated with the surface proteins of the 2nd virus, and that new coat determines the tropism of the virus
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Live attenuated vaccines - mechanism, type of immunity, time it lasts, risks, examples
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microorganism loses its pathogenicity but retains its capacity for transient growth within inoculated host.
Induces cellular (CD8+) immunity Can be life-long Can revert to virulent form, cause disease in immunocomprised, be contaminated by other viruses MMR (measles, mumps, rubella), Sabin polio vaccine, VZV, yellow fever, intranasal influenza, DPT (diptheria, pertussis, tetanus) |
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Killed vaccines - mechanism, type of immunity, time it lasts, risks, examples
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Pathogen inactivated by heat or chemicals, but maintains epitope structure; heat-stable
Induces humoral immunity Not life-long, require boosters Safer than live-attenuated Cholera, hepatitis A, Salk polio vaccine, rabies, injected Inffluenza |
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Herpes simplex virus-1 - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: respiratory secretions, saliva; latent in trigeminal ganglia Disease: Gingvostomatitis; keratoconjunctivitis; temporal lobe encephalitis; herpes labialis Dx: Tzanck smear showing multinucleated giant cells; intranuclear Cowdry A inclusions; PCR for viral DNA Tx: Acyclovir |
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Herpes simplex virus-2 - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: sexual contact, perinatal; latent in sacral ganglia Disease: Herpes genitalis; neonatal herpes Dx: Tzanck smear showing multinucleated giant cells; intranuclear Cowdry A inclusions; PCR for viral DNA Tx: Acyclovir |
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Varicella zoster virus - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: respiratory secretions; latent in dorsal root or trigeminal ganglia Disease: varicella-zoster (chickenpox, shingles); multifocal encephalitis in HIV/AIDS pts; pneumonia; reactivation of virus -> vesicular lesions distributed along trunk/sensory distribution of CN V; post-herpetic neuralgia Dx: Tzanck smear showing multinucleated giant cells; PCR for viral DNA; varicella IgG Tx: Acyclovir |
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Ebstein-Barr Virus - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: respiratory secretions, saliva; latent in B cells; seen in young adults Disease: infectious mononucleosis - fever, hepatosplenomegaly, pharyngitis, LAD of posterior cervical nodes, periorbital edema; Hodgkin's lymphoma; Burkitt's lymphoma; nasopharyngeal carcinoma Dx: Atypical lymphocytes infected by reactive CD8+ T cells; (+) Monospot/heterophile Abs Tx: if treated with -cillins -> maculopapular rash |
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Cytomegalovirus - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: Congenital, tranfusion, sexual, urine, transplant; latent in mononuclear cells Disease: congenital CMV; infections in immunosuppressed/AIDS - retinitis, pneumonia; heterophile Ab (-) mononucleosis; reactivation -> interstitial pneumonia, hepatitis, colitis, generalized disease Dx: basophilic intranuclear owl's eye inclusions; (-) Monospot Tx: Ganciclovir, Foscarnet |
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HHV-6 - family/structure, disease
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Disease: Roseala (exanthem subitum) - high fevers for several days that can cause seizures, + diffuse maculopapular rash |
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HHV-8 - family/structure, transmission, disease
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Family/structure: Herpesvirus - ds linear DNA, enveloped from nuclear membrane
Trans: sexual Disease: Kaposi's sarcoma in HIV pts |
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Adenovirus - family/structure, transmission, disease
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Family/Structure: ds linear DNA, naked
Trans: swimming pools; outbreaks in children; latent in nasopharynx Disease: febrile pharyngitis; acute hemorrhagic cystitis; pneumonia; conjunctivitis; watery diarrhea |
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Parvovirus B19- family/structure, disease
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Family/Structure: ss (-) linear DNA, naked, smallest DNA virus
Disease: aplastic crisis in sickle cell disease; erythema infectiosum/fifth disease (slapped cheeks rash); hydrops fetalis; pure RBC aplasia; rheumatoid-like sx |
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Human Papillomavirus (HPV) - family/structure, transmission, virulence factors, disease, treatment
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Family/Structure: Papillomavirus - ds circular DNA, naked
Trans: sexual VFs: HPV 16 - E6 inhibits p53; HPV 18 - E7 inhibits RB Disease: skin warts (verruca vulgaris) by types 1-4; genital warts (condyloma accuminatum) by 6 & 11; cervical + vulvar intraepithelial neoplasia by 16, 18, 31, 33; Tx: vaccine available |
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JC virus - family/structure, disease
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Family/Structure: Polyomavirus - ds circular DNA, naked
Disease: Progressive multifocal leukoencephalopathy |
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BK virus - family/structure, disease
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Family/Structure: Polyomavirus - ds circular DNA, naked
Disease: kidney disease in transplant pts |
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Poxvirus - family/structure, diseases
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Family/structure: ds linear DNA, enveloped, largest DNA virus, replicates in cytoplasm
Diseases: Smallpox due to smallpox virus; cowpox due to Vaccinia virus; Molluscum contagiosum - flesh-colored dome lesions with central dimple - due to molluscum contagiosum virus |
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Coltivirus - family/structure, disease
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Family/structure: Reovirus - ds linear RNA, naked, 10-12 segments, double icosahedral capsid
DIsease: Colorado tick fever |
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Rotavirus - family/structure, transmission, disease, treatment
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Family/structure: Reovirus - ds linear RNA, naked, 10-12 segments, double icosahedral capsid
Trans: day-care centers, kindergarten; in winter Disease: infantile gastroenteritis; villous atrophy with decreased absorption of Na+ & loss of K+ Tx: vaccination for infants |
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Poliovirus - family/structure, transmission, disease, diagnosis, treatment
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Family/Structure: Picornavirus -ss (+) linear RNA, naked; RNA translated into 1 large polypeptide & cleaved by proteases into functional viral proteins
Trans: fecal-oral (enterovirus); replicates in oropharynx & SI before spreading via bloodstream to CNS; in unvaccinated immigrants Disease: Poliomyelitis - anterior horn cell destruction (LMN injury), malaise, headache, fever, nausea Dx: CSF with increased WBCs & slightly elevated protein; virus recovered from stool or throat Tx: Salk killed & Sabin live vaccines |
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Echovirus - family/structure, transmission, disease
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Family/Structure: Picornavirus - ss (+) linear RNA, naked; RNA translated into 1 large polypeptide & cleaved by proteases into functional viral proteins
Trans: fecal-oral (enterovirus) Disease: aseptic meningitis |
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Rhinovirus - family/structure, transmission, disease
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Family/Structure: Picornavirus -ss (+) linear RNA, naked; RNA translated into 1 large polypeptide & cleaved by proteases into functional viral proteins
Trans: inhalation of aerosols Disease: Common cold; doesn't infect GI tract b/c acid-labile |
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Coxsackievirus - family/structure, transmission, disease
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Family/Structure: Picornavirus -ss (+) linear RNA, naked; RNA translated into 1 large polypeptide & cleaved by proteases into functional viral proteins
Trans: fecal-oral (enterovirus) Disease: Aseptic meningitis; herpangina (mouth blisters & fever); hand, foot, & mouth disease; myocarditis |
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Norovirus - family/structure, disease
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Family/structure: Calicivirus - ss (+) linear RNA, naked
Disease: viral gastroenteritis |
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Flavivirus - family/structure, viruses
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Family/structure: ss (+) linear RNA, naked
Viruses: HCV, Yellow fever, Dengue, St. Louis encephalitis, West Nile Virus |
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Yellow Fever Virus - family/structure, transmission, disease
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Family/Structure: Flavivirus - ss (+) linear RNA, naked
Trans: via Aedes mosquito (arbovirus); monkey or human reservoir Disease: yellow fever - high fever, black vomitus, jaundice |
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Togavirus - family/structure, viruses
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Family/Structure: ss (+) linear RNA, enveloped
Diseases: rubella, eastern equine encephalitis, western equine encephalitis |
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Rubella virus - family/structure, disease
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Family/Structure: Togavirus - ss (+) linear RNA, enveloped
Disease: Rubella/German measles - fever, postauricular adenopathy, LAD, arthralgias, fine truncal rash that starts at head; serious congenital infections |
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Coronavirus - family/structure, disease
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Family/structure: ss (+) linear RNA, enveloped, helical capsid
Disease: common cold; SARS |
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Influenza virus - family/structure, virulence factors, disease, treatment
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Family/structure: Orthomyxovirus - ss (-) linear RNA, enveloped, 8 segments, helical capsid
VFs: hemagglutinin - promotes viral entry; neuraminidase - promotes virion release; genetic/antigenic shifts - responsible for pandemics; genetic drift - epidemics Disease: Influenza (the flu); bacterial superinfection Tx: Zanamivir; killed & live vaccines |
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Parainfluenza virus - family/structure, disease
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Family/structure: Paramyxovirus - ss (-) linear RNA, enveloped, helical capsid
Disease: croup with seal-like barking cough |
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Which viruses are paramyxoviruses? What virulence factor to they share?
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Parainfluenza, RSV, Measles, & mumps
surface F (fusion) protein - causes respiratory epithelial cells to fuse & form multinucleated cells |
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Respiratory syncytial virus (RSV) - family/structure, disease, treatment
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Family/structure: Paramyxovirus - ss (-) linear RNA, enveloped, helical capsid
Disease: bronchiolitis & pneumonia in infants Tx: Ribavirin; Palivizumab |
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Measles virus - family/structure, disease
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Family/structure: Paramyxovirus - ss (-) linear RNA, enveloped, helical capsid
Disease: Measles - Koplik spots on buccal mucosa, descending maculopapular rash (includes hands & feet), coryza, conjunctivitis; Subsclerosing panencephalitis; encephalitis; giant cell pneumonia in immunosuppressed |
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Mumps virus - family/structure, disease
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Family/structure: Paramyxovirus - ss (-) linear RNA, enveloped, helical capsid
Disease: Mumps - parotitis, orchitis, aseptic meningitis, sterility |
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Rabies virus - family/structure, transmission, disease, diagnosis, treatment
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Family/structure: Rhabdovirus - ss (-) linear RNA, enveloped, helical capsid
Trans: long incubation period (weeks to months); travels retrograde to CNS; from bat, raccoon, skunk bites Disease: Rabies - fever, malaise, agitation, photophobia, hydrophobia, paralysis, coma; encephalitis Dx: bullet-shaped; Negri bodies; found in Purkinje cells of cerebellum Tx: post-exposure - wound cleansing, vaccination, & rabies immune globulin |
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Hepatitis A virus - family/structure, transmission, disease, diagnosis
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Family/Structure: Picornavirus - ss (+) linear RNA, naked; RNA translated into 1 large polypeptide & cleaved by proteases into functional viral proteins
Trans: fecal-oral; short incubation (weeks); no carrier state Disease: Usually asymptomatic; acute hepatitis; no chronic/cirrhosis/HCC Dx: anti-HAV IgM -> active hepatitis A; IgG -> prior HAV infection/prior vaccination, protects against reinfection |
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Hepatitis B virus - family/structure, transmission, disease, diagnosis, treatment
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Family/Structure: Hepadnavirus - ds DNA, partially circular, enveloped
Trans: parenteral, sexual, via birth canal, transplacental; long incubation; replicates through RT DNA pol; Disease: carrier state; serum sickness-like sx in prodromal phase; acute HBV; chronic HBV; risk of hepatocellular carcinoma (integrates into host genome & acts as oncogene) Dx: makes Dane particle; ground glass hepatocytes; lots of Abs that are on another card Tx: Vaccine - contains HBV surface Ag |
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What do each of the hepatitis B serologic markers mean? What is the window phase?
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HBsAg -> 1st marker, indicates acute infection and remains infective entire symptomatic phase, titers > 6 mos = chronic infection
Anti-HBs -> indicates resolution of acute infection & confers long-term immunity Anti-HBc IgM -> present in acute infection & window phase Anti-HBc IgG -> chronic infection (without anti-HBs) or recovery (with anti-HBs + anti-HBe) HBcAg -> antigen associated with HBV core HBeAg -> appears after HBsAg during acute infection, indicates active viral replication; detectable in chronic infection w/ high infectivity; increased risk of vertical transmission when high Anti-HBe -> low transmissability, present after recovery from acute infection Window phase - neither HBsAg or HBsAb are detected, to precipitation of Ag-Ab complexes in zones of equivalence -> removal from circulation, only Anti-HBe and Anti-HBc IgM present |
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Hepatitis C virus - family/structure, transmission, disease, diagnosis
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Family/Structure: Flavivirus - ss (+) linear RNA, naked
Trans: blood, IVDU, post-transfusion; long incubation Disease: carrier state; chronic HCV; hepatocellular carcinoma; cirrhosis Dx: anti-HCV IgG -> active infection or recovery, not protective; HCV-RNA |
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Hepatitis D virus - family/structure, transmission, disease, diagnosis
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Family/Structure: Deltavirus - ss (-) circular RNA, enveloped
Trans: parenteral, sexual, maternal-fetal Disease: Superinfection w/ HBV - HDV infection after chronic HBV with short incubation; co-infection w/ acute HBV, long incubation; chronic infection; risk of HCC Dx: anti-HDV IgM or IgG, IgG not protective |
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Hepatitis E virus - family/structure, transmission, disease, diagnosis
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Family/Structure - Hepevirus - ss (+) linear RNA, naked
Trans: fecal-oral, esp with waterborne epidemics; short incubation Disease: acute hepatitis; fulminant hepatitis in pregnant women Dx: anti-HEV IgM -> active infection; anti-HEV IgG -> recovery, protective |
