I&i Week 5 & 6 [All Bacteria]

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Gram Stain (procedure, difference between + and - staining)

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BONUS - a cell wall surrounds all eubacterial cells except wall-less bacteria such as as the mycoplasmas and Chlamydia.

Procedure: staining depends on the differential ability of ethanol or eth-acetone mixtures to extract iodine-crystal violet complexes.Then you use a counterstain.

Gram-negative: the iodine-violet complexes are readily extracted which is why the counterstain stains the wall red.
Gram-positive: the complexes are not extracted and stay violet by crystal violet.

I'm positively blue (violet)

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Components of Gram + cell wall

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1) peptidoglycan (a linear chain of two alternating sugars, N-acetylglucosamine and N-acetylmuramic acid. Each muramic acid bears a tetrapeptide of alternating L and D amino acids). 2 Polymers of either glycerol phosphate or ribitol phosphate, with various sugars, amino sugars, amino acids.

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Components of Gram - cell wall

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1) reduced peptidoglycan, some forming a single-layered sheet and the rest forming a periplasmic gel. 2) outer membrane outside periplasmic gel. The outer membrane has LPS instead of ordinary phospholipids. LPS consists of toxic Lipid A, a core polysaccharide [TOXIC MOIETY], and polysaccharide chains called O antigens in some bacteria [aka ANTIGENIC DETERMINANTS]. The outer membrane has special protein porins that make it possible for hydrophilic solute molecules to diffuse through it and into periplasm

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Functions assoc with bacterial cell membrane

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1) role in segregation of daughter chromosomes at cell division.
2) Site of DNA synthesis
3) Site of synthesis of cell wall polymers, membrane lipids
4) Contains the entire electron transport system of the cell.
5) Permeability barrier, has proteins involved in selective and active transport of solutes
6) Involved in secretion to the exterior of proteins like exotoxins and hydrolytic enzymes

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Facts about spores

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Small, dehydrated, metabolically quiescent forms produced by some bacteria in response to nutrient limitation or a related sign. ALL spore formers are Gra-positive RODS. The spore may presist for centuries and then on appropriate stimulation give rise to a single bacterial cell (germination) - a survival device. Spores can withstand pH and temo extremes including boiling water. Thermal resistance is bc of low water content and the presence of calcium dipicolinate found only in spores. Spores have tough, special coats surrounding the spore (a keratin-like insoluble structural protein)

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Bacteria and iron

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Bacteria secrete siderophores (iron chelators) to trap Fe3+ which is then transported back into bac via active transport. Bacteria must have iron to grow. There is little free Fe3+ in human blood or other body fluids bc it is sequestered by iron-binding proteins (transferrin in blood and lactoferrin in secretions)

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Protein secretion in Gram neg bacteria (GSP)

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GSP consists of cytosolic chaperones and an integral membrane translocase consisting of several proteins cooperating. 5 pathways in G- species. III and IV play a prominent role in the secretion of virulence factors.

III) 20 components causing syringe-like injection. act. by contact of the bacterial surface with host cells. Leads to the direct secretion of bacterial proteins into the cytoplasm of the mammalian cell.
IV) like type III but are also able to ransfer DNA between bac cells or between a bac and a euk cell.

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Types of mutations

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1) Replacements - substituting one base for another
2) Microdeletions/insertions - removal or addition of a single nucleotide. cause frame shift mutations
3) Insertion - addition of many base pairs of nucleotides at a single site
4) Deletion - removal of a contiguous segement of many base pairs

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Genetic exchange in bacteria

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All one way transfers of DNA from a donor cell to recipient cell

1) transformation - if competent, a bacterium can take up DNA from the environment. ability is encoded by chr genes that become active under certain env conditions. Any DNA present is bound indiscriminately. What happens to teh DNA depends on whether it shares any homology with recipient DNA --> recombination. Heterologous DNA is degraded.
2) Transduction. transfer of genetic info by bacteriophages.
3) Conjugation - transfer from d to r that reqs intimate cell contact. Need a self-transmissible plasmid (usually only plasmid DNA is transfer - chr transfer is rare)

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Plasmids (conj. vs non-conj, components, properties)

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AUtonomous extrachr elements. Ds circular DNA. Plasmids govern own replication with special sequences and proteins. Replicate within baterial host cell and are partitioned between the daughter cells. Those that can do their own transfer from cell to cell are conjugative (cant = nonconjugative). Conjugation inc a specialized sex pilus which draws the d and r cell into contact needed to form a conjugal bridge.

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Transposition

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Transposable elements (insertion sequence elements, transposions, and certain phages) are genetic units that are capable of mediating their own transfer from one chr to another, or dif spot on the same chr or between chr and plasmid. Make their own site-specific recombination enzymes called transposases.

BONUS - an IS element is small DNA seg hat encodes enzymes for site-spec recombination and a distinctive nucleotide sequences at their termini. If an IS element moves into a gene, it alters/destroys the gene activity. Transposons have more DNA containing genes.

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Direct sample vs. indirect sample

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Direct is collected directly from normally sterile tissues/fluid. Indirect is specimens of exudates (sputum, voided urine) that have passed through sites known to be colonized with normal flora (can be contaminated)

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Atmospheric conditions of bacteria

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Aerobic - Cultures of are placed in an incubator with temperature maintained at 35 to 37°C. A low concentration of CO2 is usually added because it is required by some and enhances the growth of
others.
Anaerobic - The needs of strictly anaerobic bacteria may be met by the addition of reducing agents to liquid media. An anaerobic environment for
incubation of plates can be achieved by kits which create a chemical reaction
consuming oxygen in the air leaving CO2, and nitrogen behind.
Microaerophilic - A very few (but important) bacteria have growth requirements which fall between aerobic and anaerobic. These conditions are satisfied with atmosphere-creating kits adjusted from those used for
anaerobes.

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Clostridium perfringens (Organism, Epi, path, diseases)

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1) Organism: C. perfringens is a large, g pos nonmotile rod. They make alpha-toxin a phospholipase that hydroluzes lecithin and sphingomyelin and thus disrupts host cell membranes. Some make an enterotoxin which alters membrane permeability creating fluid loss
2) Epi of gas gangre can develop in severe traumatic open lesions particuarly when there is muscle necrosis. Contamination with dirt or other foreign material introduces spores.
3) Pathogenesis - need low redox potential in the wound. this lets the spores germinate. Alpha-toxin passes along the muscle bundles prod necrosis. Increased vascular permeability --> sock, systemic disease
4) Clostridial food poisoning - if you ingest a lot of an enterotoxin-producing strain. Spores survive cooking, covert to vegetative form and multiply.
5) Diseases - gas gangrene and food poisoning. Gas gangrene - fermentation of myuscle carbs produce gas in subQ tissues - crepitation, visible on radiographs. Have to surgically excise all dead tissue/amputate + massive amts of penicillin. Can use a hyperbaric O2 chamber to slow progression.

Food poisoning - incubation pd avg = 12 hrs. Nausea, abdominal pain, diarrhea (ileum) Usually involves meat diseases. Gotta refrigerate!

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Clostridium botulinum (Organism, epi, patho, disease)

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1) Organism - spores are found in soil, pond, lake sediment all over the world. Est. lethal dose is < 1 microgram. Toxin is heat labile destroyed at 100 C, but resistant to GI enzymes. Acts at NMJ by cleaving proteins resulting in block of release of ACh --> motor neuron blockage and muscular paralysis.
2) Begins with cranial nerve palsy and descending symmetrical motor paralysis including resp. muscles (ocular, pharyngeal, laryngeal, then resp). No fever, signs of infection.
3) Epi/patho - ingestion of home-canned alkaline vegetables that have not been treated at high temps. Organism mult. in storage.
4) Incubation is 18 - 96 hours. Mortality is 10-20%
5) Other related disease is infant botulism - see other card

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Infant botulism

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Often from honey. C. botulinum x in the infants colon w/ absorption of small amts of toxin. Infant shows constipation, poor muscle tone, lethargy, feeding problems.

Need intensive supportive treatment (mech ventilation). Large doses of horse anti-toxin to neutralize free toxin.

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Clostridium tetani

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1) Organism - Makes an exotoxin, tetanospasmin, a large EC enzymatic protein. Heat labile (65 C), antigenic, readily neut by anti-toxin and intestinal proteases
2) Epi - spores are insoil, may be introduced into traumatic wounds. Can be quite small wounds, no inflmmation at the primary site.
3) Patho - need low redox potential for tetanus to germinate and make tetanospasmin. The toxin reaches the CNS by ascending the motor nerves. In the spinal cord, it acts at the level of the anterior horn cells by degrading proteins involved in NT release. BUT the toxin affecs inhibitory neurons --> unopposed active firing of motor neurons. Spasmodic contractions of both pro/ant msucles.
4) Clinical - incubation is 4 days - sev weeks depends on location = shorter transmission route to CNS. Masseter muscle ar often the first to be affected - lockjaw. Extreme cases you see opisthotons caused by massive contractions of the back muscles.
5) treat - use HTIG. Prevent with tetanus toxoid (toxin inact by formaldehyde)

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Clostridium difficile

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1) Organism - occurs in intestinal flora of 2-5% of healthy adults. Makes Toxin A and B. A is an entertoxin causing fluid secretion [aka DIARRHEA], altered mem permeability, and hemo necrosis. Toxin B is a cytotoxin which disrupts microfilaments of cells and dec cellular protein synthesis.
2) Patho - alteration of flora of adult with antimicrobials can result in overgrowth of organism with diarrhea. Psuedomembranous colitis is when there is formation of an overlying pmembrane composed of fibrin, leukos, and necrotic colon cells. PMC diarrhea may be mild and watery of blody and with cramping, leukocytosis, and fever.
3) Diagnosis - detect both toxins in stool using EIAs.
4) treat by discontinuing the problem med. Give metronidazole and vancomycin. Fecal transplant. relapses common.

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Antigens on group A Strep

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1) Lancefield carb antigen A
2) M protein (80 types)
3) Lipotechoic acid

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Haemophilus influenzae (overview)

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1) Organism - tiny (one of the smallest) Gram-neg bacilli. Can be encapsulated (6 serotypes of polysac) or non-encapsulated.
2) Encapsulated - Acute infections of CNS and soft tissue primarily in kids. Non-ecapsulated - common, less-fulminant infections of the bronchi, resp sinuses, and otitis media (usually assoc with compromise of normal clearing mechanisms via viral infection or structural damage)
3) Cultivation - req chocolate agar (lysed RBCs) that have hematin (factor X) and/or NAD (V).
4) Found in the normal NP flora of up to 80% of healthy people (a little less in adults).
5) Occ. invade into deeper tissues. bactermia then leads to spread to CNS and bones, joints. (only encapsulated)
- Often play a role in inflam exacerbation of chronic bronchitis)
6) Diagnosis - clinical findings and gram smear. Ca confirm by isolation o the org from site of infection or blood.
7) Treat - ampicillin, amoxicillin, newer cephalosporins, tetracylcin, aminoglycosides, sulfonamides. less susc. to other penicillins/erythromycin.

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Haemophilus influenzae b (traits, vaccination, epi)

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Encapsulate, with type B capsule which made up of a polymer of ribose, ribitol and phosphate, called polyuribitol phosphate (PRP).

1) Attachment to uncioliated resp epithelial cells by pili and adhesins. Can invade between cells. Capsule is antiphagocytic. Has IgA proteases. LPS outer membrane
2) Need anti-PRP Abs to be protected. However, kids can't make Ab against polysach until >18 mos (make T-cell independent response - no memory B or T cells. With conjugated vac make T-dependent better response)
- Peak incidence of Hib infection is 6-18 mos.
- Diseases include meningitis (often preceded by symps of URI, pharayngitis, sinusitis, otitis media mortality is 3-6%, 13 have neuro sequelae), Epiglotitis, cellulitis (tender, red-blue swelling in check/periorbital + fever + bacteremia), arthritis (+ fever, local inflammation + bacteremia)

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Haemophilus ducreyi

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1) Causes chancroid (VD), stricly human pathogen, sex trade workers
2) Microabrasians from sex - skin infection - 4/7 days tender erythematous papules --> pustules --> rupture to painful shallow ulcers with granulomatous bases and purulent exudates. Soft and painful unlike syph wiuch are indurate and painless.
3) Can spread to regional lymph nodes in thr gorin which become enlarged bubos which can rupter. Attract lots of CD4 T cells inc chance of getting HIV
4) Block phaocytosis (2 sec proteins), resistant to serum-mediated killing, produces a toxin (no immunity after H. ducreyi infections.
5) Hard to diagnose. Staining is poor. Can be cultured on chocolate agar but can be overgrown by other microbes (H duc is a slow grower), but use other antibiotics to knock them down

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General features of enterobacteriacae

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Antigens -
1) Outer membrane LPS is O antigen
2) Cell-surface polysaccharide (capsule or ) slime layer) = K antigen
3) Motile strains have peritrichouse flagella = H antigen.
4) Surface pili, no typing scheme

Growth medium - simple media, single carbon source, growth is rapid under both aerobic and anaerobic conditions
Epi - most primarily colonize the lower GI tract, but can survive readily nature (water). They are opportunistic. Cause UTIs and acute diarrhea. Got to do in vitro susceptibility tests bc each strain has dif combos of chr and plasmid resistance.

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Escherichia coli Toxins (4) (and their mechs)

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1) Alpha hemolysin - pore-forming cytotixin (like streptolysin O)
2) Shiga toxin (released by some E. coli and most Shigella upon lysis of the bacteria). B units binds to Gb3 (glycolipid receptor) on euk cells that is internalized in an ednocytotic vacuole. The A subunit crosses the vacuolar membrane in the trans-golgi network. enzymatically modifies 28S rRNA of 60s subunit - prevents binding of aa tRNA to the ribosome - block prot synth
3) Labile toxin: also A/B. B binds to cell mem and A ADP-ribosylates G protein which causes activation of the membrane assoc adenylate cyclase system --> cl sec, water and electrolytes in lumen
4) Stabile toxin - binds to gp receptor resulting in act of membrand guanlyate cyclase --> inc cGMP causes an LT-like secretion of fluid and electrolytes into the bowel lumen.

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E. coli pili

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E. coli has over 150 distinct O antigens and K and H antigens.
- Type 1 (common) pili bind to D-mannose residues on epi cell surfaces
- Specialized pili like P pili bind to moieties on uroepithelial cells (or others that bind to human enterocytes)

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UTI definition, patho, epi

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1) UTI = anything from cystitis to renal pelvis/kidney. Inf of upper UT carries risk of spread to the blood stream. Leading cause of g-neg sepsis/sep shock
2) E. coli accounts for more than 90% of UTI.
3) Most com in women during sexually active yrs. Resevoir is pts. own intestinal ecoli flora
4) Patho - minor trauma or mechanical effect of intervource allow bac access to the bladder. UPEC e. coli has virulence factors - P pili has digalactoside receptor on uroeptihelial cells [higher in UTI's/DIRECT CORRELATE to INFX SEVERITY/particularly HIGH IN PYELO]. Type 1 pili also bind to uepi cells and also aid in periurethral colonization [STARTS THE PERIURETHRAL COLONIZATION].
5) Factors that violate bladder integrity or obstruct urine outflow (prostate) inc risk of infection.

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ETEC (epi, patho, disease, tx/prev)

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EnteroToxigenic E. Coli = traveler's diarrhea in less-dev countries AND in infants native to those country (morb/mort during first 2 years of life).

EPI - trans by eatin food/water contaminated by human cases or convalescent carriers. Infecting dose is high so P2P trans is unusua.
PATHO - Toxins include Labile, Stabile, or both in the SMALL intestine. CFA class of pili medaites adherence. Genes for ST, LT, CFA pili are in plasmids.

DISEASE:
o Most common cause of traveler’s diarrhea - watery diarrhea that is self-limiting to 1-3 d

TX/PREV:
o Rehydration & supportive therapy
o Trimethoprim/sulfamethoxazole or quinolones to reduce duration
o Antimotility agents

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EPEC (epi, patho, disease, tx/prev)

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EnteroPathogenic E. Coli
EPI - 20% of diarrhea in bottle fed infants <1yr old. Reservoir is infant cases and adult arriers. Fecal-oral transmission.
PATHO - Attachment via BFP type pili. forms clustered microcolonies on enterocyte surface. Then you get effacement of microvilli and changes in the cell morphology like prod of "pedestals" with EPEC bac at their apex?? Also get modifcation of enterocyte cytoskeleton proteins. This is called an attachment and effacing lesion (A/E) lesion. (genetically controlled in a PAI). A type III secretion system injects at least 5 e coli sec prots (Esps) into host cell cyto + receptor for intimin. Intimin is a major attachment protein. The Esps perturb IC signal transduction.

DISEASE:
o Watery diarrhea that is self-limiting to 1-3 d
o Formation of A/E (attachment/effacing) lesions due to Esps-mediated modification of the enterocyte cytoskeleton
o Primarily targets small intestine

TX/PREV:
o Rehydration & supportive therapy
o Trimethoprim/sulfamethoxazole or quinolones to reduce duration
o Antimotility agents

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Corynebacteria diphtheriae (general, epi, patho, disease, dx, tx, prevent)

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GENERAL: Aerobic; G (+) Bacilli; chinese letter/pallisade arrangements;
EPI: droplet spread, direct contact w/cutaneous infections, rare where immunizations are, found in dev countries/lacking public health-->targets kids;
PATHO: DT: A/B, A targets EF-2 by ADP-ribosylation and shuts off protein synthesis, toxin free for reuse; c.dip can still makes proteins using another way

DISEASES: PHARYNGITIS (2-4d), TONSILITIS: malaise, sore throat, fever, pseudomembrane appearance Diphtheric MYOCARDITIS, neuro paralyis of soft palate, oculomotors, select muscle groups;
DX: Tinsdale medium, K+ Tellurite agar, gram stain;
TX: Diphtheria antitoxin, erythromycin;
PREVENT: Diphtheria toxoid/ DTaPl

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Listeria monocytogenes (general, epi, patho, disease, dx, tx, immunity)

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GENERAL: facultative, G(+) Bacilli; EPI: animals (fowl), cole slaw, soft cheese,packaged meat, transplacentally, beta; targets pregnant women, fetus, neonate, elderly, immunocompromised
PATHO: grows in refrigerated temperatures. Internalin--reorganization of the actin cytoskeleton Listeriolysin O (pore-forming tox): escape phagolysosomes of macrophages; epith cell to cell protrusion actin mech
DISEASE: Food-borne: Primary infection--nausea, abd pain, diarrhea, fever; Disseminated infx: fever, malaise; CNS tropism--meningitis, encephalitis; Neonatal: Intrauterine infx-->Fetal stillbirth, neonatal sepsis,
DX: blood or CSF culture dep on infx loc [with cold enrichment
TX: Penicillin G, ampicillin, TMP/SMX, [Ampicillin + Gentamicin for fulminant cases!]; IMMUNITY: CD4/CD8

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Bacillus anthracis (general, epi, patho, disease, dx, tx)

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GENERAL: Aerobic or facultative spore-forming, G(+) Bacilli (coccobacilli to long chain); POLYPEPTIDE capsule: antiphagocytic, exotoxin complex, [increases cAMP, decreases ACh -> edema in lungs];
EPI: Spread animals (herbivores), skin contact, inhaled, beta
DISEASE: Cutaenous anthrax: 2-5d, malignant pustule, Pulmonary anthrax: 1-5d respiratory distress, cyanosis;
DX: Ordinary media;
TX: Penicillin, Chemophylaxis: Doxycycline, ciprofloxacin;
PREVENTION: vaccine from nonencap filtrates-->toxin complex

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Mycobacterium tuberculosis (general, epi, path, disease, dx, tx, prevent, immunity)

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GENERAL: strict aerobe, G(+) Bacilli; slim, HYDROPHOBIC cell surface, acid fast; EPI: droplet, unpasteurized milk
DISEASE: Primary TB: initial infection in unsensitized individuals, affects middle/lower lobes, multiply in macrophages, microscopic granuloma, multinucleated giant cells; fever, malaise, enlarged hilar lymph nodes, Ghon complex; Reactivation TB: apex of lungs, caseous necrosis, dry cough progresses to hemoptysis, stress induced, fever, malaise, fatigue, sweating, weight loss, loss of lung tissue, kidneys, vertebrae; Chronic pneumonia: fever, cough, bloody sputum, chronic wasting to death; DX: acid fast bacilli (AFB), Lowenstein-Jensen (LJ) medeium after 3-6w with radiometric detection, purified protein derivative (PPD) of tuberculin skin test; TX: isoniazid, ethambutol, rifampin, pyrazinamide, streptomycin; PREVENTION: heat, and UV, isoniazid, BCG (bacirallus, Calmette, and Guerin) vaccine IMMUNITY: delayed-typer hypersensitivity (DTH) - NK cells, cell-mediated immunity (CMI), CD4+/8+

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Mycobacterium leprae (general, epi, path, disease, dx, tx, immunity)

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GENERAL: G(+) bacilli acid fast, slow grower; EPI: grown in footpads of mice and armadillo, infected humans reservoir, supposedly transmitted through nasal secretions (lepromatous);PATHO: must multiply in host cells--prefers macros and schwanns/peripheral sensory nerves (anesthesia); DISEASE Leprosy (2-7d) via minor skin lesions, invasion of macrophages and Schwann cells; Tuberculoid leprosy: granulomas, giant cells, large, flattened plaque on face, trunk, limbs, with raised, erythematous edges and dry, pale, hairless centeres, non-contageous; Lepromatous Leprosy: deficint CMI, extensive, symmetric, diffuse skin lesions on face, with thickening of lips, forehead, and ears - leonine apperance, loss of nasal bones, septum, digits, testicular atrophy, RES involvement; DX: acid-fast stained scrapings, skin biopsy; TX: sulfones (dapsone) - blocks para-aminobenzoic acid metabolism. + Ripampin for 6m cures TL. + clofazimine for 2y for LL.; IMMUNITY: CMI; LEPRO: NEGATIVE lepromin skin tests/progressive; TUBER: POSITIVE lepromin skin tests/minimal disease

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Actinomyces (israelii) (general, epi, path, disease, dx, tx,)

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GENERAL: anerobic G(+) bacilli, microaerophilic, branch at acute angles, irregular staining; EPI: found in normal intestinal flora; assoc with dental hygiene/tooth extraction/mouth trauma; DISEASE: Actinomycosis: cervicofacial area, firm, fibrous mass, localized chronic endometritis (IUDs); DX: clinical presentation (nature of lesion/slow prog course/hx of trauma predisposing/condition, biopsy, sulfur granules; TX: Penicillin G 4-6w

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Nocardia asteroides, Norcardia brasiliensis (general, epi, path?, disease, dx, tx, immunity, targets)

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GENERAL: strict aerobe, G(+) bacilli, weakly acid fast, branching,; EPI: soil, inhalation or prick; DISEASE: Nocardiosis/ confluent bronchopneumonia: dyspnea, fever, cough, sputum production, acute inflammation, suppuration, parachyma destruction, lymphadenitis, FOCAL NEURO SIGNS; Skin infection: after minor trauma, superficial pustul; DX: blood agar; TX: sulfonamides, TMP-SMX; IMMUNITY: T-mediated; TARGETS: immunocomp.

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Neisseria meningitidis (general, epi, path, disease, dx, tx, prevent, immunity)

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GENERAL: aerobic, G(-) diplococci, 12 serogroups (A,B,C, Y, W-135); EPI: droplet transmission esp closed areas (army/dorms)/families, kids under 6 [6mo-2yrs: peak incidence period], found in nasopharygneal of 10% healthy people; PATHO: Polysaccharide capsule antiphagocytic, OMP, LOX, lipid A, pili (attach), LSP/LOS mimics self brain, sialyated LOS bind to factor H to downregulate complement using host sialic acid; DISEASE: Acute, purulent meningitis: fever, nuchal rigidity, headache, seizures, mental signs, increased intracranial pressure, rash, purpura, arthralgia, bulging anterior fontanelle (infants), thrombocytopenia, progresses to Disseminated intravascular coagulation (DIC) syndrome: scattered skin petechiae (endotoxin caused vascular necrosis), shock, bilateral hemorrhage of adrenal glands, slow-grade fever, arthritis, bacteremia, endotoxemia; DX chocolate agar, oxidase positive; TX: Penicillin, 3rd generation cephalosporin; PREVENTION: rifampin, ciprofloxacin, MCV4 vaccine (A, C Y, W135 serotypes) [TYPE B NOT AT ALL IMMUNOGENIC bc likely similar to a NEURAL CellAdhessionM--aka hole in N. menin coverage]; IMMUNITY: group-specific antipolysaccharide antibody, capsular polysaccharides T-independent IgG2

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Neisseria gonorrhoeae (general, epi, path, disease, dx, tx, prevent, immunity)

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GENERAL: aerobic, G(-) diplococci,sticky clusters EPI:sexual contact via mucosal surfaces, asymptomatic carriers reservoir; PATHO:OMP (Protein I A&B), invasion; OPA adherence protein (Protein II), LPS/LOS mimics self, bind to Factor H to downregulate complement using host sialic acid, fast antigenic change/ variation (pili-recombination[MOST IMPORTANT]/OMP--frameshift), peptidoglycan fragments, pili; DISEASE: PID: fever, lower abdominal pain, adnexal tenderness, leukocytosis, infertility, ectopic pregnancy Gonorrhea (2-7d) MEN( purulent urethral discharge, dysuria), WOMEN(increased vaginal discharge, urinary frequency, dysuria, abdominal pain, menstrual abnormalities, dyspareunia), can lead to Disseminated gonococcal infection (DGI): fever, migratory polyarthralgia, petechial, maculopapular/pustular rash, Opthalmia: conjunctivitis in neonates, Rectal gonorrhea, pharyngeal gonorrhea, cervicitis, urethritis, salpingitis, urethritis (acute), epididmytis; DX: chocolate agar from [urethra/cervix], oxidase +; TX: 3rd generation cephalosporin, opthalmia: erythromycin eye drops; PREVENTION:no vaccine, use barrier methods during intercourse; IMMUNITY: none, prone to multiple infections

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Vibrio cholerae(general, epi, path, disease, dx, tx, prevent)

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GENERAL: aerobic/anaerobic G(-) bacilli, curved single flagella; EPI: contaminated saltwater, crustaceans and plankton, pH 8.0-9.5, fecal-oral, sea food; PATHO: LPS, O Antigenic structure, CT: A/B toxincatallyzes ADP ribosylation of G protein yielding constant activation of adenylate cyclase and cAMP accumulation, Toxin-coregulated pilus (TCP), polysaccharide capsule in O139 serotype; DISEASE: Cholera (2-5d) water and electrolyte shift from inside cell to intestinal lumen, isotonic dehydration, hypokalemia, metabolic acidosis from bicarbonate loss. Rapid onset, abdominal fullness, gurgling, rushes of peristalsis, loose stools, rice-water stools; DX:thiosulfate-citrate-bile salt-sucrose agar; TX: tetracyclines, pregnant/children: TMP/SMX, erythromycin; PREV: good sanitation, cooking of crustaceans

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Camphylobacter jejuni (general, epi, path, disease, dx, tx,)

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GENERAL: microaerophilic, G(-) bacilli, curved single flag; EPI: animals (sheep, cattle, uncooked chickens, wild birds, dogs), contaminated water, unpasteurized milk; PATHO: low infecting dos, move using Microtubs over actin; DISEASE: Diarrhea (1-7d): lower abdominal pain, fever, watery or blood/pus, self-limiting 3-5d, Guillain-Barre syndrome: cross reaction of LPS core with myelin; DX; oxidase positive, iso from stool; TX: erythromycin (Floroquninones gaining resistance)

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Helicobacter pylori (general, epi, path, disease, dx, tx,)

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GENERAL: microaerophilic, G(-); EPI: human (fecal-oral); PATHO: Urease: survive low pH via ammonia roduction, Vacuolating cytotoxin (VacA): induce eukaryotic apoptosis, pathogenicity island (PAI), Cag protein, flagella: adherence; DISEASE: Gastritis, gastric ulcer, duodenal ulcer: burning upper abdominal pain, nausea, vomiting, flank bleeding/rupture, anoexia, belching adenocarcinoma, Bastric B-cell lymphoma (MALT); DX: gastric mucosal biopsy, culture, IgG/IgA; TX: Bismuth salts (Pepto-Bismol) + 2 of: Metronidazole, tetracycline, clarithromycin, amoxicillin

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Salmonella typhi (general, epi, path, disease, dx, tx, immunity)

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GENERAL: G(-) motile; EPI:human (fecal-oral); PATHO: Vi antigen: lowers infecting dose, LPS endotoxin: seeding causes fever; M-cell entry/marcophage invection mech--block oxidative metabolic burst; DISEASE: Typhoid fever: extended fever, sustained bacteremia, subtle rash, enlarged spleen, headache, abdominal pain. Bacteria ingested by macrophages (inhibit oxidative metabolic burst), proliferate, enter lymphatics to reticular endothelial system (mesenteric lymph nodes, liver, spleen). Then re-enters the gut via bile; most important complication: hemorrhage through ileal perforation DX: blood or stool culture; TX: ampicillin, TMP/SMX, resistant strains: use ceftriaxone, ciprofloxacin; IMMUNITY: humoral and CM

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Salmonella enterica (general, epi, path, disease, dx, tx, immunity)

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GENERAL: G(-) motile; EPI: Animals (poultry, exotic pets- turtles), Humans (food handlers), animal feces, found in industrialized societies; PATHO: invade enterocytes small/large bowel transcytose-->produce inflamm resp (surface adhesins-->ruffles->bacteria enter, type III injection; DISEASE: Food poisoning/ Salmonellosis: (24-48h)abdominal pain, nausea, vomiting, diarrhea for 3-4d, bacteria invade enterocytes, induce inflammatory response, membrane ruffling induce internalization of bacteria, infection of bone; DX: blood/stool culture; TX: Fluid/electrolyte replacement; antibiotics not used because increased duration & freq of carrier state; IMMUNITY: humoral and CMI

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Bordetella pertussis (general, epi, path, disease, dx, tx, immunity)

Back 43

GENERAL: G(-) bacillus (coccobac); EPI:droplet, previously immunized adults (reservoir), targets kids <1 yr; PATHO: PT--A/B toxin, ADP-ribosylation abolishes inactivation circuit of adenylyl cyclase;adenylate cyclase toxin (ACT): converstion of host ATP to cAMP, hemolytic/cell signalling/chemotaxis/superoxide gen fx--]microbicidal fx of polys/monos; Tracheal cytotoxin (TCT): death of ciliated tracheal cells; filamentous hemagglutinin (Fha): adherence; surface pili, pertactin, highly contageous; DISEASE: Whooping cough: (7-10d) ciliated cells are progressively destroyed producing cough, paralysis and cell death of neutrophils, macrophages and lymphocytes, LYMPHOCYTOSIS, histamine sensitization and insulin secretion. (1) Catarrhal stage (1-2w): mucoid rhinorrhea, malaise fever, sneezing, anorexia, communicable, (2) Paroxysmal coughing stage (2-4w): inspiratory whoop then cough, vomiting, mucoid secretions, apnea in infants (3) Convalescent stage (3-4w): decreased symptoms; DX: [nicotinamide supplement culture charcoal needed, nasopharyngeal swab]; direct immunofluorescent antibody (DFA); PCR; serology; ABSOLUTE lymphocytosis; TX: supportive mostly--antimicrobials to limit spread: erythromycin, clarithromycin; IMMUNITY: IgG against PT, pili and pertactin, DTaP

Front 44

Mycoplasma pneumoniae (general, epi, path, disease, dx, tx)

Back 44

GENERAL: lacks a cell wall but has sterol containing triple layer membrane, poor staining; EPI: droplet spread, low infecting dose 100 colony forming units, fx ages 5-15 yrs; PATHO: attaches to cilli/microvilli by CYTAHESIN binds to sialic acid containing groups; interfere with cilli-->desquamation--->inflammed; DISEASE: Primary Atypical Pneumonia (PAP)/ Walking Pneumonia: non-productive cough, fever, malaise, headache, scattered areas of pneumonia, attaches to cilia and microvilli, binds sialic acid, desquamation of mucousa leading to inflammation; DX: mycoplasma agar, X-ray showing pneumonia in lower lobe; TX: erythromycin, tetracycline, azythromycin, clarithromycin, quinolones

Front 45

Pseudomonas Aeruginosa (general, epi, patho, disease, dx, tx)

Back 45

GENERAL: aerobic, G (-), make colorful, water soluble pigments, oxidase + (help diff from enteros), HIGHLY ANTIBIOTIC RESISTANT; EPI:in persons with underlying diseases: leukemia, cystic fibrosis, burns; water, soil, vegetation; PATHO: LPS, porin proteins, slime layer of alginate, extotoxin A: catalyzes EF-2 by ADP ribosylation and shuts down protein synthesis leading to cell death, Exoenzyme S: ADP-ribosylates cytoskeleton vimentin, Elastase: acts on elastin, IgA, IgG, complement, collagen; PLC: degrades host phoshoplip/ beta hemo on agar; DISEASE: attachment via pili, flagenna and slime; local destruction that is rapid and destructive; alveolar necrosis, vascular invasion, infarcts, bacteremia, black, necrotic ulcers. Otitis externa: swimmer's ear, Pneumonia in CF patients, Osteomyelitis in Diabetics, burn wound infections, sepsis, UTI and pyelonephritis in catheterized patients, Right endocarditis in IV drug users, corneal infections in contact wearers; DX; oxidase positive, pyocyanin production (greenish-blue wound); TX: newer aminoglycoside, gentamicin, tobramycin, amikacin, carbenicillin, ticarcillin, 3rd generation cephalosporins, monobactams

Front 46

Legionella pneumophila (general, epi, patho, disease, dx, tx, immunity)

Back 46

GENERAL: G(-) thin, pleomorphic requires L-cys, ferric ions, ph 6-9. EPI: aerosoled, immunocomp'd people, found in fresh water warm weather/ac units; PATHO:presist in adequate chlorine, extract iron, invades phages in alveoli/term bronchioles, outer membrane protein (OMP): macrophage invasion potentiator (Mip): mediates cell entry, prevent lysosome fusion, lytic destruction of inflammatory cells; DISEASE: Necrotizing Multifocal Pneumonia:headache, fever, chills, dry cough may turn purulent, chest pain, myalgia, chills, pleuritic chest pain, vomiting, diarrhea, confsion, delirium, shock respiratory failure; DX: direct fluroescent antibody (DFA), bufferend charcoal yeast extraction (BCYE), PCR, Lp antigenuria detection; TX: erythromycin, macrolides (azithromycin, clarithromycin); IMMUNITY: cell mediated response> humoral

Front 47

Borrelia recurrentis/hermsii (general, epi, patho, disease, dx, tx, prevent, immunity)

Back 47

GENERAL: G(-) spirochete; EPI: tick-borne w/ small rodent/animal reservoir tickbite [woods] OR Louse-borne human reservoir louse crush release Borr in superficial wound/mucosal [contracted in"extreme circumstances", only b. recurrentis]; PATHO: spirochetes circulating-->fever/endotoxin like...in-between fevers-->sequestered in internal organs...OMP constantly changing causing recurrent evasion of immune system DISEASE: Relapsing fever: high fever, headache, myalgia, weakness, rigors, 1 week fevers and relapse after 2-4d. DX: Giemsa, Wright staining blood smears; TX: tetracycline, erythromycin; PREVENT: de ticking/lousing, rodent ctrl, pesticides; IMMUNITY: humoral/lysis using comp

Front 48

Borrelia burgdorferi (general, epi, patho, disease, dx, tx, prevent)

Back 48

GENERAL: G(-) spirochetes microaerophilic; EPI :transmitted via ixodes ticks from whitefooted mouse (reservoir-early)--> deer (late stages) and/or humans in wooded area, new england/mid atlantic states [nymph feeding]; PATHO: Changes in antigenic makeup OpsA:major outerprotein when in ticks, OpsC: outer protein to facilitate transmission to human, stimulate protective Ab...chronic Lyme/ arthritis has some autoimmunity; OspA cross reactive autoAg; DISEASE: Lyme disease: fever, "bulls eye" skin rash spreading from bite - erythema migrans, myalgia, joint pain, meningeal irritation, fatigue, headache, long term meningoencephalitis,myocarditis and relapsing arthritis (large joints: knees). After weeks: nervous, cardiovascular involvement; DX: exposure and typical clinical findings; TX: Doxycycline and amoxicillin for 30-60d; PREVENT: clothes/prevent exposure; vaccine no longer available due to OspA autoimmune responses

Front 49

Treponema pallidum (general, epi, patho, disease, dx, tx, immunity)

Back 49

GENERAL: anaerobic, G (-) spirochetes, endoflagella, motile with flexion and rotation; EPI: sexual contact via mucosal surfaces/ over 50% transmission where lesion is present, asymptomatic carriers (reservoir)..also IV drug use, transfusion, transplacentally; PATHO: spiro goes to subendothelial tissues, multiplies slowly-->endarteritis-->necrotic ulceration-->granulomatous cuffs form, bacteria spread via lymphatics, avoid immune recognition via molecular mimicry, bind to host proteins, Igs, and complement, no toxins, DISEASE: Primary Syphilis: enter via genital ulcer (indurated, painless, firm base, rasied margins) chancre, Secondary Syphilis: (2-8w)maculopapular rash, enlarged lymph nodes, fever malaise, condylomata lata [painless mucosal warty genital lesions], highly infectious, followed by latency,Tertiary Syphilis [not infectious] (5yrs), neurosyphilis: chronic meningitis, fever, headache, focal neuro findings, tabes dorsalis, cardiovascular syphilis medial necrosis of vasa vasorum, ruptured aortic aneurysm, enarteritis, gumma; Congenital Syphilis: rhinitis, maculopapular rash, saddler nose, saber shins, anemia, thrombocytopenia, liver failure; DX: dark field microscopy, immunoflorescence, Nontreponemal test: reagin Ab against cardiolipin, rapid plasma reagin (RPR), Veneral Disease Research Lab tests (VDRL) [TO TELL IF YOU ACTIVELY HAVE IT, HIGH DURING PRIM/SECOND (cept IN HIV pts), goes AWAY W/ TX] Treponemal tests: fluorescent treponemal ab (FTA), microhemagglutination (MHA-TP) [ALWAYS REMAIN NO MATTER WHEN INFECTED]; TX: Penicillin, tetracyclines, erythromycin, cephalosporins; IMMUNITY: humoral but mostly cell mediated + macros; relapse related to balance of cellular immunity and T cell supression

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Yersinia Pestis (general, epi, patho, disease, dx, tx)

Back 50

GENERAL: facultative G(-) bacilli, bipolar staining; EPI: fleas on rodents, droplets; PATHO: Protein prod b/w diffent temps 25C (flea) to 35C (human), 3 DIFFERENT virulence plasmids, Yersinia outer membrane proteins (Yops)-type III secretion systems, F1 capsular ag, V &W--antiphagocytic: intracellular, plasminogen-activating protease, spread via blood; DISEASE: Bubonic plague: (2-7d) not contageous, fevergram-negative septic shock; Pneumonic plague:worse than bubonic highly contageous via droplets, mucoid then blood sputum, cyanosis; hemorrhagic suppurative lymphadenitis - bubo DX & TX: bipolar staining/DFA and use streptomycin and/or doxycycline; (w/o antibiotics 50-75% die, 10-20% w/)

Front 51

Francisella tularensis (general, epi, patho, disease, dx, tx)

Back 51

GENERAL: faculatative, G(-) coccobacilli that requires sulfhydryl compounds; EPI: wild mammal, bloodfeeding arthropod, skinning animals--fx on people spend time in endemic areas: farmers/hunters; PATHO: invades phages,released from phagosome, survives in cytoplasm only to return to membrane compartment, 2 DIFF bacterial secretion symptoms; DISEASE: Tularemia (2-5d): infects reticuloendothelial organs, granulomas, chronic relapsing course, fevers, chills, ulceroglandular: local papule that is necrotic, ulcerative, swollen/painful lymph nodes, oculoglandular: painful, purulent conjunctivitis, typhoidal: prolonged fever, pneumonic: follows inhalation; DX: serology MOST common 4 fold titer increase, PCR, DFA, culture on cysteine rich media (chocolate or thayer-martin); TX: streptomycin, gentamicin, ciprofloxacin, doxycycline

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Chlamydia trachomatis (general, epi, patho, diseaseS, dx, tx)

Back 52

GENERAL: obligate intracellular bacteria--only replicate in other living cells, NO RIGID CELL WALL multiple serovars (diff OMPS) ; EPI: MOST COMMON STD, fx humans, sexual mucosal contact, asymptomatic humans (reservoir); PATHO: Elementary Body (EB): infectious form/compact/hardy; Reticulate Body (RB): replicative form, protein synthesis; DISEASE: GENITAL INFECTION: (B, D-K) sexual transmission, causing urethritis, epididymitis, cervicitis [w], salpingitis [w], PID [w], tropism for endocervix, dysuria & discharge infiltration of inflammatory cells result in fibrosis and scarring long term [leads to sterility/ectopic pregnancy]; TRACHOMA (A-C) blindness,corneal scarring, conjunctival deformities, inversion of eyelashes (trichiasis) chronic inflammation/infx of eyelids; INCLUSION CONJUNCTIVITIS contact cervical secretion during birth, acute mucopurulent eye discharge 5-25d after birth; Lymphogranuloma venerum (LGV) (L1-L3) genital lesions, multiocular suppurative inguinal lymph nodes, inguinal adenopathy, matted and suppurative bubos DX: eptih cell sample at infection [cervical/uretheral/conjunctival], direct fluorescent antibody (DFA), PCR [urine samples/most sensative]; TX:tetracyclines, macrolides, some fluoroquinolones, LGV - doxycycline, trachoma - single dose of azithromycin; IMMUNITY: short-lived if any against any strain

Front 53

Chlamydia pneumoniae (animals), Chlamydia psittaci (birds)

Back 53

respiratory pathogen, Atypical pneumonia

Front 54

Rickettsia rickettsii (general, epi, patho, disease, dx, tx, prevent)

Back 54

GENERAL: G(-) coccobaccilli intracellular pathogens; EPI: animals, tick; PATHO: LPS, large proteins, peptidoglycan, induction of endocytosis using E, exits, takes over actin pol; DISEASE:Rocky Mountain Spotted Fever: (2-6d) [CLASSICE TRIAD: fever, severe headache,rash], myalgia, small erythematous macules becomes petechial, rash on palms and soles--> moves centripetally, toxicity, mental confusion; rash can lead to necro/gangrene; DX: serologic tests (culture difficult), clinical signs, symptoms, epidemiology; TX: Doxycycline effective in 1st week; less in 2nd/if DIC present PREVENT: de-ticking

Front 55

Rickettsia prowazekii (general, epi, patho, disease, dx, tx)

Back 55

GENERAL: G(-) bacilli intracellular pathogens, Giemsa stain works best; EPI: transmitted through louse person to person--worse in crowded living spaces/times of misery; PATHO: louse takes blood meal from acute febrile infected human to another/defecates while feeding; can have long term survival & typhus relapse aka Brills-Zinsser; DISEASE: Typhus: (1-2w) fever, headache, maculopapular rash on trunk-->extremities, malaise, myalgia, myocarditis, CNS dysfunction, 60% untreated die: DX: serology most reliable, epi/clinical signs, rarely cultured; TX: tetracycline, cloramphenicol, doxycyclone; DDT to fumigate lice

Front 56

Shigella dysenteriae [A], flexneri [B], boydii [C], sonnei [D] (general, epi, patho, disease, dx, tx, prevent)

Back 56

GENERAL: bacilli non motile, 4 species [A,B,C,D], 38 serotypes all by sonnei further divided; EPI: transmitted fecal-oral/contaminated water targeted against young kids; PATHO: low infecting dose (<200 organisms), acid resistance,reaches intestine and invades colonic mucosa via M cells-->inflammation, abcess formation, mucosal ulceration; Invasin protein antigens (IpaA, IpaB, IpaC, etc.): attachment, cytoskeleton reorganization, actin polymerization, apoptosis [of M cells/macros]; Stx: some cases DISEASE: Shigallosis: dysentery, adherence to M cells via Ipa, cell-cell invastion via projections; focal ulcers; stools with WBC, RBCs, and bacteria; Febrile dysentery syndrome: TRIAD [cramps, tenesmus (painful, straining defecation), frequent, small-volume, bloody mucoid discharge]; DX: stool culture with special Hektoen agar; TX: self-limiting; PREVENT: sewage disposal, water chlorination

Front 57

Bacteroides fragilis (general, epi, patho, disease, tx)

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GENERAL: anerobe but oxygen tolerant (superoxide dismutase prod), G(-) bacilli polysaccharide capsule; EPI: less than 10% of the normal colon; PATHO: resists phago, stimulates abcesses, may inhibit macrophage migration; DISEASE: deep pain and tenderness below the diaphram, INTRA-ABDOMINAL abscess (polysaccharide capsule), fever; TX: resistant to pencillins & other beta lactams-->use clindamycin, metrinodizole, imipenem, ceftriaxone

Front 58

S. Aureus

Back 58

GENERAL/EPI: Gram-positive cocci
• Forms clusters
• Coagulase +
• Catalase +

Spread
• Airborne
• Direct contact
• Nasal shedding
• Food contamination
• Lesion

PATHO:

Toxins
• Alpha toxin- pore forming toxin
• Exfoliatin- Intercellular splitting of epidermis
• StaphSAgs-
1. Enterotoxin: GI symptoms (vomiting)
2. TSST: Endothelial effect leading to capillary leakage, shock, hypotension

Primary Infection
• Surface proteins bind to glycoprotein fibronectin
• Alpha-toxin injury
• Leads to boil formation
• Can spread to distant organs

Toxin-mediated Disease
• Exfoliative- blister seperation
• Menstruation associated TSS can occur

DISEASE:
Primary Infection
• Furuncle/boil- Develops in hair follicle, sebaceous gland, sweat gland
• Impetigo- Secondary invader of group A strep
• Deep lesion- Infections of deep tissue, including bones, joints, deep organs

Toxin-mediated Disease
• Scalded Skin Syndrome- From Exfoliatin. Leads to erythema and desquamation at remote sites
• TSS- High fever, vomiting, diarrhea, sore throat, muscle pain. Also leads to renal and hepatic damage (from shock). Rash may develop. Negative blood cultures.
• Food Poisoning- Enterotoxin leads to vomiting and diarrhea in 1 to 5 hours.

DX:
• Blood agar culture
• Coagulase Test
• Catalase Test
• Positive blood culture seen in staph arthritis, osteomyelitis, and endocarditis

TX/PREV:

• Boils will resolve spontaneously
• Penicillins and cephalosporin
• Variation in susceptibility:
o Methicillin for penicillin resistance [altered target mech]
o MRSA resistance comes from alterations in peptidoglycan.
• MRSA- vancomycin and erythromycin
• Penicillinase opens beta-lactam ring

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S. epidermidis

Back 59

GENERAL/EPI:
• Gram-positive cocci
• Coagulase negative
• Immunosuppressed and neutropenic affected
• Implanted catheters and prosthetic devices increase susceptibility

PATHO:

• Contamination of prosthetic devices
• Some strains produce slime (extracellular POLYSACCHARIDE BIOFILM) which provides adhesion/mechanical barrier to host defense

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Group A Streptococci

Back 60

GENERAL/EPI: • S. pyogenes
• Gram-postive cocci
• Beta-hemolysis- Strep S and Strep O
• Lancefield antigen +
• More than 80 serotypes based on M protein
• Epidemiology:
o Pharyngitis: person-to person, persists for 1-4 weeks, in kids
o Impetigo: Transient skin lesion combined with trauma, spread by scratching
o Wound and Puerperal Infections: Treatment by physicians
o STSS: Soft tissue infection, multi-organ
o Poststreptococcal sequelae: Acute rheumatic fever- pharyngitis. Recurrences can be retriggered by GAS
o Poststreptococcal glomerulonephritis- skin and respiratory strep

PATHO:

Virulence Factors
• M protein: 1) Adhesin in nasopharynx, subcorneal keratinocytes 2) Strep resistance to phagocytosis by binding fibrinogen and serum factor H (affects complement pathway
• Lipotechoic Acid: Scaffold by M protein
• Protein F: Adherence to antigen-presenting Langerhans
• Streptolysin O- pore-forming toxin
• StrepSAg- Cytokine promotion
Acute Infection:
• Adhesins from M, LTA, and F
• See above for M protein
• SLO (other exotoxins)-mechanism of injury
STTS:
• Massive cytokine release
• Enhanced invasiveness- difference from Staph
Post-streptococcal Sequelae
• Acute Rheumatic Fever: Type II hypersensitivity- molecular mimicry of M protein against SARCOLEMMA, MYOSIN, and SYNOVIUM (ARTICULAR CARTILAGE)
• Acute Glomerulonephritis: Type III hypersensitivity

IMMUNITY: • Antibody for only same type of M protein
• IgG-reverses antiphagocytic effect of M protein
• Complement- classical mechanism

DISEASE:
Strep Pharyngitis:
• Acute sore throat, malaise, fever, and headache. Red, swollen, with yellow-white exudate. Cervical lymph nodes
• Can spread to produce peritonsillar or retropharyngeal abscess, otitis media, acute sinusitis, supparative cervical adenitis
• Extensive spread- meningitis, pneumonia, metastatic infections
Impetigo
• Primary lesion is small vesicle surrounded by erythema
• Vesicles enlarge→ yellow crust
Erysipelas
• Strep infection of the skin and subcutaneous tissue, affects the dermis
• Erythema and edema
Scarlet Fever
• Need StrepSAg
• Buccal mucosa, temples, cheeks red, except for pale area around mouth and nose
• Tongue-exudate and strawberry-like
• Rash→upper chest to trunk and extremities
STTS
• Starts in skin/soft tissue with necrotizing fascitiis + myonecrosis
• Systemic infection continues as nausea, shock, diarrhea followed by hypotension, shock, organ failure
• Lymphocytosis, azotemia, and over half cases bactermia
Acute Rheumatic Fever
• Fever, carditis, chorea, subcutaneous nodules, polyarthritis
• Cardiac enlargement, murmurs, effusions→heart failure
• Untreated lasts 2 to 3 months
Acute Glomerulonephritis
• Edema, hypertension, hematuria, proteinuria, lower complement levels

DX:
• Blood agar plates to demonstrate B-hemolysis
• Initally: Rapid Strep test
• Followup: culture with group A antigen
• ASO found in rheumatic fever

TX/PREV:

• Penicillin G
• Penicillin prophylaxis to prevent recurrences
• Prophylaxis during procedures such as dental extraction

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Group B Streptococci

Back 61

GENERAL/EPI:

• S. agalactiae
• Gram-postive cocci
• Beta-hemolysis- Strep S and Strep O
• Lancefield antigen +
• 9 antigenic types based on polysaccharide capsule
• Capsule containing sialic acid
• Epidemiology:
o Leading cause of sepsis and meningitis in first day of life
o Resident to GI tract but secondarily spread to vagina
o During pregnancy organisms gain access to amniotic fluid or colonize as pass thru birth canal
o Risk factors: Premature infant (lower innate immunity) and prolonged exposure-rupture of amniotic membrane
o Healthy infants can develop 1-3 months later

PATHO:
Virulence Factors
• Sialic acid binds serum factor H, ineffective alternate pathway, c3b

IMMUNITY:
• Antigen-type specific IgG. (type III most common)
• Prenatal protection via transplacental IgG transfer

DISEASE:
• Nonspecific symptoms: respiratory distress, fever, lethargy, irritability, apnea, hypotension
• Pneumonia-common
• Meningitis (5-10%)
• Onset is first couple days
• With treatment: mortality 20 percent
• Adult infection: peripartum chorioamnionitis, pneumonia, skin infections

DX:
• Isolation of GBS from blood or cerebrospinal fluid

TX/PREV:
• Penicillin usually with aminoglycoside
• Reduced contact of the infant
• Intrapartum antimicrobial prophylaxis with penicillin/ampicillin
• Requires screening during 3rd trimester

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Strep pneumoniae

Back 62

GENERAL/EPI:
• Gram-positive, oval cocci
• Typically arranged as diplococci
• Alpha-hemolysis
• Bile salts accelerate hemolysis
• Epidemiology
o Leading cause of pneumonia, meningitis, bactermia, otitis media
o Most common in young and elderly populations

PATHO:
Proteins/Toxins
• Pnuemolysin- Pore forming toxin--direct effect on cilia contributes to the disruption of the endothelial barrier facilitates the access of pneumococci to the alveoli and eventually their spread beyond into the bloodstream
• Surface capsule- prevents phagocytosis and complement activation

• Aspiration of respiratory secretions (host factor impairment contributes such as COPD)
• In alveoli, pneumolysin is toxic to pulmonary endothelial cells helps in promoting dissemination in blood

IMMUNITY
• Provided by antibody against capsule, specific to capsule

DISEASE:
Pneumococcal pneumonia
• Begins abruptly with chllls and high fever
• Cough with pink to rusty sputum common
• Pleuritic chest pain
• Lobar consolidation on X-ray

Pneumococcal Meningitis
• Most common at advanced age, can precede pneumonia
• Can also cause sinusitis and otitis media. Also, endocarditis, arthritis, and peritonitis

DIAGNOSIS:
• Routine culture
• Use of bile (acceleration of growth compared to other alpha hemolytic bacteria

TX/PREV:
• Penicillin, however increased resistance from alterations in transpeptidase

Prevention:

• Polysaccharide vaccine containing 23 most common serotypes

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Viridans Strep

Back 63

GENERAL/EPI:
• Gram-positive cocci
• Alpha-hemolytic
• Lack carbohydrate antigens of pyogenic and capsule of pneumococcus
• Comprise of members of normal flora


PATHO:
• Only occurs if protection from host can occur
• Need to be protected by fibrin and platelets
• Can produce glucans and polysaccharide polymers to enhance attachment to valves

DISEASE:
• Can cause subacute endocarditis
o Reaches previously damaged heart valves by disruption of natural enviro., such as tooth extraction

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Enterococci

Back 64

GENERAL/EPI:
• Gram-postive cocci
• Share bacterial characteristic of S. pyogenes
• Beta-hemolysis- Strep S and Strep O
o Lancefield antigen D

Epidemiology:

o Derived from GI-part of the normal intestinal flora
o Common in hospital environment- people with extensive surgery, devices, or dialysis

DISEASE:
• Opportunisitc Urinary Tract Infections

• Soft Tissue Infections

• Associated with UT manipulations, malignancies, biliary tract disease, GI disorders

TX:
• Resistant to B-lactams and aminoglycosides
• Ampicillin

Front 65

EHEC (general/epi, patho, disease, tx/prev)

Back 65

GENERAL/EPI:
EnteroHemmorhagic E. Coli


Epidemiology:

• Consumption of products from animals colonized with EHEC strains (e.g. unpasteurized juice, milk, hamburgers)
• Low infecting dose = person-person transmission does occur and cooking might not kill sufficient bact to prevent transmission
• Cattle are the reservoir

PATHO:
• Shigella toxin- HUS
• A/E lesions (mediated by Esps, intimin)

DISEASE:
• Starts off as a watery diarrhea which then becomes a bloody afebrile diarrhea on days 1-2 and that resolves in 3-10 days

• Primarily targets colon

• Circulating Stx can cause HUS in 10% of cases (oliguria, edema, pallor, hemolytic anemia, thrombocytopenia, renal failure)

TX/PREV:
o Rehydration & supportive measures
o If HUS occurs, hemodialysis or hemapheresis may be necessary
o Antimicrobials contraindicated d/t higher risk of HUS

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EIEC (general/epi, patho, disease, tx/prev)

Back 66

GEN/EPI:
EnteroInvasive E. Coli

Epidemiology

o Higher infecting dose than Shigella = lower person-person transmission
o Humans are the only known reservoir

PATHO:
• Similar to Shigella (see Shigella)
[ Invasin protein antigens (IpaA, IpaB, IpaC, etc.) that are injected into the host cell and mediate cell attachment, cytoskeleton reorganization, actin polymerization, and induction of apoptosis
o Fingerlike projections into other cells, listeria-style
• Some produce Stx]

DISEASE:

o Watery diarrhea that becomes dysentery with blood + pus in the stool in children under 5 years of age living in developing nations.

TX/PREV:
o Rehydration & supportive therapy
o Trimethoprim/sulfamethoxazole or quinolones to reduce duration
o Contraindicated- antimotility agents

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Brucella (general/epi, patho, disease, tx/prev)

Back 67

GEN/EPI:

• Gram-negative coccobacillus
• Grow slowly (2-3 days) on blood agar plates

Epidemiology:
o Disease of large mammals, particularly cattle, goats, and pigs
o Occupational expsure for farmers, vets, abattoir
o Unpasteurized dairy products
o Skin breaks, ingestions, aerosolized microbes

PATHO:
Virulence Factors
o Smooth LPS: mediates in cell entry
o Type IV secretion allows to survive intracellularly and forms replicative phagosome where it survives and multiplies

o Multiplies in non-immune macrophages
o Localizes in RES organs and multiplies withing macrophages
o Facultative intracellular pathogen- invade dendritic cells, epithelial cells, and placental trophoblasts
o Granulomas in RES

IMMUNITY:
o CMI mediated
o Activated macrophages kill microbe

DISEASE:
o Recurrent bacteremia with fever (undulant- cyclical chills and fever at night)
o Suppresses host cellular immune response to develop long-term infection
o Night sweats, headache, arthritis, spontaneous abortion, endocarditis

DX:
o Serology: Done by ELISA
o Blood culture (dangerous

TX/PREV:

o Tetracycline
o Doxycycline + Rifampin
o Need to treat for at least 6 weeks