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217 Cards in this Set
- Front
- Back
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Gram positive rods (3)
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Bacillus
Clostridium Listeria |
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Gram positive filaments (2, tests)
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Acid fast aerobe - Nocardia
Acid fast negative anaerobe - Actinomyces |
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Gram positive cocci (2 major classes, 1 additional differentiator)
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Catalse + -> Staph (coagulase + -> s. aureus)
Catalase -> Strep |
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Streptococcus hemolysis classes
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Alpha: s.pneumoniae (capsulated, optochin sens), viridance strep (no capsule, optochin resist)
Beta - Group A s.pyogenes (bacitracin sens), Group B s. agalactiae (bacitracin res) Gamma - enterococci |
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S. Pneumoniae causes . . . (4)
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MOPS
Meningitis Otitis media Pneumoniae Sinusitis |
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S. Pyogenes causes - pyogenic, toxigenic, immunologic (2,3,3)
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Pyogenic - pharyngitis, cellulitis, impetigo
Toxigenic - toxic shock-like syndrome, scarlet fever Immunologic - rheumatic fever, glomerulonephritis |
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Protein A (organism, MOA)
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S. aureus
Binds Fc of Ig -> blocks opsonization and phagocytosis |
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IgA protease (organisms (3), MOA)
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S. pneumo, H.influenza B, Neisseria
Cleaves IgA to allow colonization of respiratory mucosa |
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M protein (organism, mechanism)
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Group A strep (s. pyogenes)
Prevents phagocytosis |
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Clostridium (4 species and key feature for each)
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Gram positive rod
C. tetani -> spastic paralysis C. botulinum -> flaccid paralysis C. perfringens -> gangrene C. difficule - diarrhea, 2/2 abx use |
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Macrophages vs neutrophils (where, life span, killing)
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Macs: long-lived, in tissues, not much O2 dependent killing
Neutrophils: short-lived, circulating, vigorous respiratory burst |
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Phagocytic receptors (3)
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Integrin and complement - recognize C3b coated organism
Fc receptors - bind IgG if preformed Ab exist Lectins - recognizes specific carbohydrates |
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Phagocytic activating receptors
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Classical - innate inflammatory response: TLR, TNF, iFN, IL-1
Alternative - late response, non inflammatory: IL-4, IL-13, Th2 mediated |
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Fever path (5)
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Exotoxin (eg LPS) ->
Leukocyte activation -> Pyrogenic cytokines (TNFa, IL-1β -> Circumventricular organs -> Prostaglandins -> Heat retention -> rise in core body Temp |
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Acute phase response (7)
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Lethargy
incr CRP, decr albumin Inhibition of bone formation Decr serum Fe and Zn (to keep away from pathogens) Incr WBC and platelets Decr RBC |
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5 non-infectious causes of fever
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Malignancy
Granulomatous disease (sarcoid) Collagen vascular disease (SLE, RA) Drug reactions (dilantin) Fictitious |
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Toxins: phospholipases (1 example)
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Cleave phosphatidylcholine (lecithin)
Eg. c.perfringens alpha toxin |
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Toxins: superantigens
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Staph and strep -> toxic shock syndrome
Activate 1 in 5 T cells -> massive cytokine release |
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Cholera toxin
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Turns Gsalpha permanent only
G protein that -> adenylate cyclase -> incr cAMP -> decr Na absorption and incr Cl absorption -> WATER LOSS -> "rice-water" stool |
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Tetanus and botulism toxins
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Tet: blocks release of GABA -> spastic paralysis
Bot: blocks Ach -> flaccid paralysis |
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C. difficile toxin
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Rho GTPases keep tight junctions b/w epithelial cells
Toxin blows apart junction |
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Gram negative cocci (2, one test)
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Neisseria:
Maltose fermenter -> meningitidis Maltose nonfermenter -> gonorrhoeae |
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Gram negative coccoid rods (2)
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H. Influenza
Bordella pertussis |
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Gram negative comma shaped (2, 2 tests)
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All are oxidase positive
42deg -> campylobacter Alkaline -> vibrio cholera |
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Gram negative rods classes
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Lactose fermenters: klebsiella, e.coli
Lacose nonfermenters: Oxidase + : pseudomonas Oxidase - : shigella, salmonella, proteus |
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Gram negative comma shaped, oxidase +, grows at 42
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Campylobacter
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Gram negative comma shaped, oxidase + grows in alkaline media
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Vibrio cholera
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Gram negative rod, lactose nonfermenter, oxidase +
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Pseudomonas
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Gram negative rod, lactose nonfermenter, oxidase -
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Shigella
Salmonella Proteus |
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Main differences b/w gram neg and gram pos (2)
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Gram pos have thick peptidoglycan
Gram neg have thin peptidoglycan and an inner AND outer lipid membrane |
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Spirochetes (3)
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Borrelia - Lyme
Treponema pallidum - Syphillis Leptospira |
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Respiratory Gram negatives (4)
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Bordetella
Haemophilus Legionella Pseudomonas in immunocompromised |
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Common microbes in heart infections (3)
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S. aureus -> ABE
Viridans strep -> SBE Enterococcus -> SBE |
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Anaerobic abscesses
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Bacteroides fragilis - a normal gut flora
Intestines leak into peritoneal cavity -> b. fragilis follows -> other facultative anaerobes consume O2 so b. fragilis can thrive |
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Normal flora (skin, nose, oropharynx, dental plaques, colon, vagina)
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Skin - Staph epidermidis (Staph aureus)
Nose - Staph epidermidis, staph aureus Oropharynx - viridans strep Dental plaque - strep mutans Colon - bacteroides fragilis > e. coli Vagina - lactobacillus, e. coli, group b strep) |
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Staphylococci durability features (4)
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Non-spore forming
Facultative anaerobes Dessication/heat resistant High salt concentration resistant |
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Differentiator for S.aureus and S.epidermidis
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S.aureus is yellow on MSA plate
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S. aureus (encounter, entry, multiplication)
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Carried in 30% of pop on skin, nares
Entry via trauma, surgery Extracellular multiplication |
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S. aureus virulence factors (2)
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1. Protein A binds Fc to block phagocytosis
2. TSST-1 superantigen |
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S. aureus toxin-related disease (3)
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Toxic shock syndrome - fever, rash, hypotension
Food poisoning: short onset, caused by enterotoxins Staph scalded skin syndrome: intraepidermal blisters, in neonates and children, by exfoliative toxin |
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S. aureus resistance and Rx
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Many staph are have B-lactamase, resistant to 1st line penicillins
Use B-lactamase resistant B-lactam: nafcillin If resistant to nafcillin -> vancomycin (+gentamicin) |
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MRSA (CA vs HA acquired, 1st line Rx)
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usually Hospital acquired
Community acquired has more soft skin and tissue infections Vancomycin is first line Rx |
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Acute bacterial endocarditis most common cause
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S. aureus
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S. epidermidis
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Normal skin flora
Infects prosthetics and catheters |
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S. saprophyticus
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UTI
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Novobiocin positive
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S. saprophyticus (as opposed to the other coagulase negative s. epidermidis)
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Strep agalactiae (class, main cause, mnemonic)
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Group B, beta hemolytic
Normal in female genital tract -> neonatal sepsis, meningitis, pneumonia (use prophylactic penicillin) Group B, Baby, Brain |
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Strep bovis (class, main causes (2)
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Group D Strep
Normal gut flora -> correlates w/ colon cancer when found in blood Subacute endocarditis |
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Enterococci (class, 2 features, 1 main cause)
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Group D Strep
Normal GI flora Lots of resistance --> endocarditis |
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Strep pyogenes (class, encounter, localized vs systemic infections, main antigen)
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Group A Strep
Encounter - normal skin/mucosal flora in 5-25%; pharyngitis from inhalation (cool climate); impetigo from touch (warm climate) Pharyngitis and impetigo are localized infections Necrotizing fasciitis is systemic M protein (blocks phagocytosis by binding complement factor H) |
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Fever, white exudate on tonsils, rash on limbs and trunk
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S. pyogenes
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S. pyogenes disease not caused by exotoxins (3 w/ rx)
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Impetigo - superficial skin infection w/ fragile vesicles (rx - antibiotics)
Cellulitis and erysipelas - deeper skin infection that spreads rapidly w/ systemic sx (rx - oral abx) Necrotizing fasciitis - rx aggressive abx + surgery |
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Pharyngitis w/ strawberry tongue and rash
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Caused by GAS (pyogenes) exotoxin
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Strep pyogenes disease caused by exotoxins
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Scarlet fever
Toxic shock syndrome |
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Non-infectious complications of s. pyogenes
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Glomerulonephritis - immune complex deposition
Acute rheumatic fever -> valvular heart disease |
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S. pyogenes Rx
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Penicillin for 10 days
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Strep pneumoniae risk factors (3) and Rx (1)
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Pre-existing lung damage (smokers)
Immunocompromised Splenectomy (loss of spleen -> incr risk of infection from encapsulated organisms) Rx - ceftriaxone |
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Osteomyelitis (what is it, common spread/sites, dx)
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Progressive inflammatory destruction of bone, necrosis, new bone formation
Hematogenous spread to distal femur and prox tibia common in children Bone biopsy = gold standard |
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Osteomyelitis major pathogens (3 age groups)
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Neonates - S. aureus, strep
Infants - S. aureus Later in life - S. aureus, mixed infections |
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Osteomyelitis minor pathogens (4)
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Sickle cell -> salmonella
Cat/dog bites -> pasteurella multocida Vertebral -> TB (Pott's disease) |
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Septic arthritis (3 clinical)
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Sudden articular pain
Tenderness/swelling/warmth in joints Knee > hip > shoulder |
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Septic arthritis common organisms (3)
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S. aureus > strep > n.gonorrhoeae
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Gonococcal septic arthritis (2 presentations)
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Monoarticular septic arthritis
Dermatitis-septic arthritis: traid of dermatitis, migratory polyarthralgias, tenosynovitis + fever |
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Bacteremia primary vs secondary
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Primary: direct invasion of blood stream (nosocomia, ivdu, trauma)
Secondary: infection at other site leads to bugs invading blood (pyelonephritis, pneumonia) |
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Infective endocarditis: acute vs subacute
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Acute - invasive, pathogenic organisms w/ toxic course
Subacute - less pathogenic bacteria -> more indolent course |
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Bacteremia clinical (2 main, 3 specifics)
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Fever
Lethargy/mental status If skin: cellulitis If pneumonia: pleuritic CP or cough If pyelo: back pain |
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Infective endocarditis predisposing factors (4)
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Valvular heart disease (RHD, CHD, MVP)
Idiopathic hypertrophic subaortic stenosis Prostethics IVDU |
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Infective endocarditis path (6 and 1 hallmark)
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Turbulence/trauma to valvular endothelium -> platelets-fibrin -> nonbacterial thrombotic endocarditis -> THEN trauma and bacteremia -> adherence/colonization -> VEGETATION
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Infective endocarditis clinical (5)
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Constitutional symptoms
Back pain FEVER Murmur Emboli |
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Osler nodes
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Small painful nodes on pads of fingers/toes
Caused by circulating immune complexes Infective endocarditis |
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Janeway lesions
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Hemorrhagic, painless macules on palms/soles
Infective endocarditis |
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Consequences of vegetations in infective endocarditis (5)
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Distal site infections (myocardial abscess)
Host response w/ proinflamm cytokines -> fever, sweats, chills Tissue destruction by organism Emboli Immune complex formation -> glomerulonephritis |
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Beta lactams MOA and resistance mechanisms
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Bactericidal
Inactivate transpeptidases (penicillin binding proteins, PBPs) required for peptidoglycan synthesis Beta lactamase inactivates |
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Beta lactams classes (4)
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Penicillins
Cephalosporins Monobactams Carbapenems |
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Oxacillin (class, 1 use, 2 tox)
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Penicillin beta lactam
Staph aureus Hypersensitivity, interstitial nephritis |
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Ampicillin/Amoxicillin(oral) (class, use, 3 tox)
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Intermediate spectrum Aminopenicilin beta lactam
Penicillinase sensitive Gram pos and neg rods (h.flu, listeria, e.coli, salmonella, proteus) Hypersensitivity, ampicillin rash, pseudomembranous coliits |
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Penicillin (class, 2 main use, 2 tox)
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Beta lactam
Gram positive (s. pneumo, s.pyo, actinomycyes), SYPHILIS Hypersensitivity, hemolytic anemia |
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Clavulinic acid use
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Combine w/ amoxicillin/ampicillin
Inhibits beta lactamases |
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Piperacillin/Ticarcillin (class, 2 uses, 1 tox)
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Extended spectrum beta lactam
Pseudomonas, enterobacter Hypersensitivity |
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What two cephalosporins penetrate CSF?
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3rd gen - Ceftriaxone
4th gen - Cefipime |
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Cephalosporins (activity, resistance, excretion, 1 pearl)
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Bactericidal
Inhibit cell wall synth but less susceptible to penicillinase Renal excretion Less allergy Only 5th gen has activity against enterococci |
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Cefazolin (class, use (4))
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1st gen cephalosporin
Penicillin-resistant S. aureus that is not MRSA (gram pos cocci) Proteus, E.coli, Klebsialla |
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Cephalosporins (5 gens)
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1st - cefazolin
2nd - cefuroxime 3rd - ceftriazone 4th - cefipime 5th - ceftaroline AZ - U - TRI - IPI TAR |
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Cefuroxime (class, uses (5))
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2nd gen cephalosporin
Gram pos cocci Proteus, E.coli, Klebsiella, H.flu |
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Ceftriazone (Class, uses (3), 1 key feature)
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3rd gen cephalosporin
Serious gram neg resistant to other beta lactams N. Meningitis/Gonorrhoeae, S. Pneumo Penetrates CNS |
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Ceftazidime (class, use)
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3rd gen cephalosporin
Pseudomonas |
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Cefepime (class, use)
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4th gen cephalosporin
Gram pos and pseudomonas |
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Ceftaroline (class, use)
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5th gen cephalosporin
MRSA and gram neg except pseudomonas |
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Cephalosporins toxicity (2)
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Less hypersensitivity than PCN (DON'T GIVE TO PT W/ KNOWN SEVERE RXN TO PCN)
Nephrotoxicity |
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Aztreonam (class, use)
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Monobactam cell wall synth inhibitor
B lactamase resistant Gram neg rods Low tox |
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Imipenem/Cilastatin (class, use, tox (2))
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VERY broad spectrum B-lactamase resistant carbapenem
(Cilastatin inhibits drug inactivation in renal tubules) Seizures, nephrotoxic |
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Vancomycin (Class, use (3), tox (3))
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Glycopeptide cell wall inhibitor - binds d-ala d-ala portion of precursors (not PBP)
No x-resistance w/ beta-lactams Gram pos serious resistant organisms: MRSA, C.difficile, enterococci Tox: Red-man diffuse flushing (block w/ antihistamines), nephro, ototox |
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Daptomycin (moa/class, use, tox)
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Lipopeptide cell wall inhibitor via formation of K channel
Gram pos: mrsa, s. pyo, VRE Tox: skeletal muscle |
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Pneumonia: modes of infection
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Aspiration of fine particles: TB
Inhalation of droplets: influenza, meningococci Aspiration from nasopharynx: pneumococci, legionella, gram neg enterics |
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Pathogens causing community acquired pneumonia (2 typical, 3 atypical)
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Viruses
Pneumococcus (40%) Atypicals: Mycoplasma in young Chlamydia Legionella (most lethal) Enteric gram neg rods in elderly |
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Contrast bacterial and viral pneumonia (nature, sputum, ausc, xray, wbc)
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Bacterial: consolidating, purulent/rusty sputum, fremitus, focal consolidation, elev wbc)
Viral: nonconsolidating/diffuse, no sputum, normal ausc, diffuse xray, normal wbc) |
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Legionairre test
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Urinary antigen
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Strep pneumoniae test
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Urinary antigen
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CAP Rx (3)
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Macrolides
Quinolone - elderly Doxycycline |
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Pathogens causing pneumonia in immunocompromised (2 classes, 5 pathogens)
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Decr cell-mediated (HIV):
Pneumocystis Fungi Mycobacteria CMV Humoral immunity (CVID) Encapsulated (S.pneumo) |
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Hospital acquired pneumonia pathogens (entry,class of paths w/ one eg, dx)
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Entry - aspiration b/c gram negs colonize pharynx
Gram negative rods (pseudomonas) Dx - culture |
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HAP Rx
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Broad spectrum beta lactam
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4 pathogens that cause nosocomial pneumonia and risk factors
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S. aureus - coma/diabetes/renal failure
Legionella - high dose steroids Pseudomonas - steroids Acetinobacter - steroids |
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Acetinobacter (risks, site of disease, rx)
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Invasive procedures
Pneumonia and bacteremia Lots of resistance |
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Pseudomonas aeruginosa (class, 3 high risk patients, toxin)
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Gram neg rod, oxidase positive
Nosocomial, burns, cystic fibrosis Exotoxin A inactivates EF-2 |
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How does pseudomonas grow in CF lung?
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Starts as piliated non-mucoid and progresses to non-piliated mucoid via alginate capsule
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Pseudomonas Rx
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Aminoglycoside + extended spectrum penicillin - piperacillin
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Legionella identification
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Fastidious growth
Charcoal medium Gram negative rod |
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Legionella (encounter, entry, spread)
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Grow in amoeba biofilms in water coolers, spas . .
Inhaled aerosols -> lyses amoeba and enters macrophages to multiply Disease localized to lungs |
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Legionella (risk factors, 2 diseases)
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Immunosuppresion, dialysis, cancer, alcohol
Legionnaire's - immunocomprosimed,fever, pneumonia w/ 15% mortality Pontiac fever - healthy, self-limiting fever |
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Legionella Rx
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Erythromycin
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Protein inhibitors (cidal or static, moa, resistance)
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Bacteristatic
Inhibit 30S or 50S Resistance - target site mod, active efflux, enzyme inactivation |
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Protein Synthesis Inhibitors (6)
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Aminoglycosides - bacteriCIDAL
Tetracyclines Chloramphenicol Macrolides Linezolid Clindamycin |
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Linezolid (class, use, 2 tox)
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Protein synth inhibitor
Resistant gram positive Bone marrow suppression Reversible thrombocytopenia |
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Tetracyclines (class, uses (6), 1 tox)
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Protein synth inhibitors
Accumulates intracellularly so used: Chlamydia, Rickettsia, Gonorrhoeae Borrelia, H.pylori, M. pneumo Avidly binds teeth and bones -> yellow discoloration in children/pregants |
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Tigecycline (class, 1 use)
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Tetracycline protein synth inhibitor
Resistant gram neg and pos rods - PSEUDOMONAS |
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Gentamicin (class, 2 uses, 2 tox)
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Aminoglycoside protein synth inhibitor
Not taken up by anaerobes Gram neg facultative rods Synergy w/ beta lactams Tox: nephrotox, ototox (esp incombo w/ loop diuretics) |
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Aminoglycoside resistance and one other key point
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transferase enzymes inactivate drug
Concentration dependent killing -> once daily dosing and post antibiotic effect |
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Chloramphenicol (class, 1 use, 2 tox)
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Protein synth inhibitor
Meningitis Aplastic anemia and gray baby syndrome |
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Macrolides (class and 3 examples)
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Protein synth inhibitors
Eyrthomycin Clarithromycin Azithromycin |
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Erythromycin (class, 1 use, 2 tox)
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Macrolide protein synth inhibitor
Atypical pneumonias (chlamydia, mycoplasma, legionella) Tox: GI and QT prolongation |
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Azithromycin and clarithromycin (class, uses)
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Macrolide protein synth inhibitors developed to be have less tox and longer t1/2 than erythromycin
Same use: atypical pneumonias |
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Clindamycin (class, 1 use, 1 tox)
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Lincosamide protein synth inhibitor
Anaerobic infections (b.fragilies, clostridium perfringens) in abscesses Tox: c.difficile -> colitis |
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Which protein synth inhibitors aren't bacteristatic?
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Aminoglycosides are bactericidal
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Secretory diarrhea (2 pathogens, description, location)
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V. cholera
ETEC Copious, watery, no tissue invasion Small bowel |
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Dysentery (2 pathogens, description, location)
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Shigella
Entamoeba Small volume w/ blood/mucus/pus, invasion Large bowel |
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Hemorrhagic colitis (1 pathogens, description, location)
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EHEC
Medium volume, bloody, no invasion Large bowel |
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Secretory bloody diarrhea (3 pathogens, description, location)
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Salmonella
Campylobacter Yersinia Copious, watery, bloody, pus, sometimes tissue invasion Ileum and colon |
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Contrast upper and lower bowel pathogens (volume, invasion, systemic sx, fecal wbc, blood)
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Upper: fluid loss, no systemic systems, no fecal wbc, not bloody
Lower: small, volume, invade mucosa (shigella, campylo), systemic sx, fecal WBC, bloody |
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Enterotoxigenic E. Coli (ETEC) (type of diarrhea, toxin)
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Water diarrhea, Traveler's
Heat-labile toxin similar to cholera toxin |
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Shigella (type of diarrhea, entry and multiplication)
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Gram neg, non lactose fermenting rod
Bloody diarrhea (dysentery), like EIEC Enter M cells -> multiply in cytoplasm of epithelials and macs Actin-comet tail |
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Shigella toxins (3)
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Type III secretion - cell invasion and apoptosis
Actin nucleation protein - cell-cell spread Shiga Toxin - A-B toxin that inhibits protein synth |
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Enterohemorrhagic E. Coli (EHEC) (type of diarrhea, 2 toxins and their damages)
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Hemorrhagic colitis (bloody medium volume)
Shiga-like toxin -> HUS Attaching and effacing lesions via type III secretion system, intimin, and tir |
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Salmonella (type of diarrhea, identifier, 2 types of disease based on 2 different serotypes)
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Secretory, bloody diarrhea
Produce H2S Typhoid fever - salmonella invades intestinal epi --> lymph nodes -> seeds organs -> fever, abd pain, rose spots Gastroenteritis -> most common: nausea, abd pain |
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Salmonella: enteric vs typhoid fever
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Typhoid fever - fever, diarrhea, headache
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Clostridium difficile disease (5)
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Watery diarrhea
Fever Loss of appetite Nausea Abd pain/tenderness |
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Pseudomembranous colitis (pathogen, path, 2 causes)
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Caused by C.difficile toxins
Destruction of enterocyte cytoskeleton 2/2 clindamycin or ampicillin |
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Top 3 pathogens causing UTIs
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E. coli
Staph saprophyticus Klebsiella pneumoniae |
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Cystitis sx (3) and rx
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Dysuria
Urgency Frequency Nitrofurantoin or TMP-SMX 3-5 d |
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Pyelonephritis sx (4 and rx)
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Fever
Chills Flank pain (CVA) / tenderness Incr WBC Quinolone 7-14 d or Beta-lactam + gentamicin |
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Pyuria
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WBC in urine
Abscence of WBC rules out UTI but not presence does not equal infection |
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2 types of recurrent UTI
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Relapses - interval b/w recurrence is less than 2 wks, image if multiple relapses
Reinfections - interval b/w recurrence > 2wks, most UTIs |
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When to treat asymptomatic bacteruria
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Pregnant women (7d TMP-SMX
Newborns (due to reflux) Urologic manipulation (cytoscopy) |
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Bacterial infections requiring bactericides (3)
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Endocarditis
Osteomyelitis Meningitis |
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Meningitis symptom triad
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Fever, stiff neck, headache
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6 encapsulated organisms and what main disease they can cause
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MENINGITIS
S. Pneumo H. Flu N. Meningitidis E. Colie K1 Group B strep in neonates Cryptococcus neoformans |
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3 CSF profiles in meningitis
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Purulent - PMNs, low glucose ->bacterial (acute)
Lymphocytic low glucose -> TB, fungal, spirochetal, listeria, sarcoidosis (acute or subacute) Lymphocytic normal glucose -> viral (subacute) |
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Anatomic differences b/w purulent and lymphocytic low glucose profiles
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Purulent - cranial surface
Lymphocytic low glucose - base of brain -> CN palsies |
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Risk groups for meningitis pathogens (4 groups)
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Neonate: Group B strep, E. coli, Listeria
Young adult: N. Meningitidis > S. Pneumo Older: S. Pneumo > N.Meningitidis Immunosuppressed: Cryptococcus, Listeria |
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Drug-induced meningitis (3)
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NSAIDs
TMP-SMX IVIG |
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Key lymphocytic low glucose meningitis pathogen not to miss
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TB
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Chlamydia trachomatas pneumonia (epi, encouter, entry, rx)
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Infants
Encounter - infected mother's birth canal Entry - conjunctivitis/nasopharyngeal into phagocytes, lives intracellularly in vacuole of epithelials Self-limiting disease (almost everyone has been infected) |
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N. Gonorrohoeae (toxins and agar)
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No toxins, damage done by immune response
Chocolate agar |
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N. Gonorrohoeae (entry, spread, virulence)
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Colonized mucosal surfaces so secretions all carry Gc
Can penetrate mucosal layers -> pelvic inflammatory disease and occasionally disseminates Evades immune system via pili antigen variation |
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N. Gonorrohoeae Rx
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3rd gen cephalosporin - Ceftriaxone
Assume chlamydia coinfection and treat w/ doxycycline or azithromycin |
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Syphilis organism
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Treponema pallidum spirochete
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Syphilis stages
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Primary - chancre, painless 3wk post exposure, SERONEGATIVE
Secondary - disseminated disease w/ maculopapular rash on palms and soles, systemic disease and contagious Tertiary - 1/3 secondary progress 30 yr later, noncontagious, arteritis, neurosyphilis, granulomatous inflammation |
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Syphilis Dx
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Can't isolate
PCR or serological |
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DNA and metabolic toxins (3 classes and their basic MOA)
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Quinolones - inhibit DNA gyrase and topoisomerase
Metronizadole - metabolites directly damage DNA Sulfa derivatives - inhibit bacterial and protozoal folate synth |
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Fluoroquinolones (cidal or static? 3 examples. MOA, resistance)
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Bactericidal
Ciproflaxacin, levofloxacin, moxifloxacin Block bacterial DNA gyrase Resistance: active efflux, dna gyrase mutation |
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Ciprofloxacin, levofloxacin, moxifloxacin
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Fluoroquinolone DNA gyrase inhibitors
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Fluoroquinolones (use, SE (3))
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Gram neg rods
DONT USE W/ ANTACIDS Cartilage damage -> don't use in children or pregnant women Tendonitis |
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Metronidazole (moa, 4 uses, 3 se)
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Metabolites damage DNA
Giardia, Entamoeba, Trichomonas, Anaerobes SE: GI, metallic taste, disulfiram like reaction w/ alcohol |
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Sulfonamides (cidal or static?, moa, 2 resistance, 4 se)
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Bacteriostatic
PABA antimetabolites inhibit dihydropteroate synthetase Resistance: widespread via target side mod, increased PABA synth SE: Kernicterus, drug interactions, hemolytic anemia if GP6D, Stevens Johnson |
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Kernicterus
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Sulfa adverse effect
CNS injury due to toxic effects of high concentrations of bile pigments in infants Sulfa displace bilirubin from albumin -> incr free bilirubin |
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Sulfa drug resistance
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Decreased permeability, and mutant target site
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Lyme Rx
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Doxycycline
Ceftriaxone |
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Ehrlichiosis (disease, type of organism, transmitted by)
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Human monocytic ehrlichiosis
Rickettsia Transmitted by Amblyomma |
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Anaplasmosis (disease, type of organism, transmitted by)
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Human granulocytic anaplasmosis
Rickettsia Transmitted by Ixodes (like B.Burg) |
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Ehrlichiosis and Anaplasmosis (clinical and rx)
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Nonspecific fevers chills
HME (ehr) -> maculopapular or petechial rash Rx - doxycycline or tetracycline |
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Babesiosis (where does it multiply, transmitted by, 2 clinical, 1 key dx)
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Intra-erythrocytic parasite
Transmitted by Ixodes Fever, hemolytic anemia Maltese cross on smear |
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Rocky Mountain Spotted Fever (organism, clinical triad, 1 epi)
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Rickettsia rickettsii
Rash on palms, soles (migrating to trunk), headache+fever Endemic to east coast |
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Bordetella Pertussis (class, agar plate, encounter, multiplication)
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Gram neg coccobacillus
Fastidious -> CCBA plate Encounter - respiratory droplets Adheres to ciliated bronchial epithelial cells -> multiplies extracell and inhibits mucociliary clearance |
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CCBA plate
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Bordetella
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Bordetella Pertussis Toxin
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Pertussis toxin - ADP ribosylating A-B toxin
Increases cAMP by inhibiting Gsa which normally inhibits adenylate cyclase |
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Bordetella Pertussis Rx and Prevention
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Rx - Azithromycin (resistant to penicillin)
Vaccine - pertussis proteins |
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H. pylori (class, epi, toxin)
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Gram negative curved/spiral
Fastidious Infections are widespread and clinically silent Cag type 4 secretion system |
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H. pylori stages of damage
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D-wk: superficial gastritis
wk-mo-yr: chronic gastritis mo-yr: MALT lymphoma, adenocarcinoma |
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H. Influenza type B (class, causes, colonizes)
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Gram neg coccobacillus
Causes meningitis and pneumonia in < 5 yo Colonizes upper respiratory tract |
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N. Meningitis (normal flora?, rx, prevention)
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Normal flora in upper resp tract (compared to N. Gono NOT normal)
Ceftriaxone Vaccine for college students |
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Functions of normal flora (6)
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Produce+secrete B12 and vitK
Digest food (carb, proteins, FA) Digest endogenous (urea, bilirubin,bile salts) Drug metabolism (warfarin Educate immune system Suppress other pathogens (c.diff) |
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Which fungi is human commensal?
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C. albicans
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How do fungi typically cause host damage? (4)
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Usually self-limiting, mild damage
Don't produce toxins Destroy tissues by invasion Fungus ball occlude arteries, veins, bronchi |
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Coccidioidomycosis (where?, 4 clinical, histopath)
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Epi: SW US
Pneumonia, meningitis, rash Disseminates in immunocompromised -> Histopath: spherule w/ endospores |
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Spherule filled w/ endospores
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Cocciodiomycosis
SW US |
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Candida albicans (entry, 3 clinical)
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Opportunistic normal flora
Oral and esophageal thrush, diaper rash Disseminates to any organ |
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Cryptococcus neoformans (key feature, common clinical scenario, 1 clinical presentation)
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ENCAPSULATED
Most people are resistant AIDS patients -> meningitis Umbilicated papules |
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Cryptococcal meningitis Dx
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CSF cryptococcal antigen
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Fungus ball
Septate hyphae 45deg angle branches |
Aspergillus
More common in cancer than HIV |
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Amphotericin B (moa, 2 se)
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Antifungal binds ergosterol
SE: infusion-related - cytokines -> fever/chills nephrotox |
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Fluconazole (moa, se)
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Inhibits ergosterol synthesis by inhibiting CYP P450
SE: drug interactions |
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Flucytosine (moa, se)
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Interrupts DNA and protein synth
SE: bone marrow suppression |
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Echinocandins (moa, organism, tox)
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Antifungals inhibit cell wall synth
Aspergillus Low tox |
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Basic antifungal Rx principles
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Local: fluconazole or ketoconazole
Systemic: amphotericin B |
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Opportunistic fungi (3)
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Aspergillus
Candida Cryptococcus |
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If infected w/ HIV and TB, what is the chance of active infection each year? What is it for non-HIV?
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8% per year
5-10% lifetime |
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TB pathogenesis
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Inhale aerosol ->
No host reaction b/c bland capsule -> Multiplies in macs -> hilar lymph nodes -> Silent bacillemia -> lung apices and latent TB |
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Progressive primary and miliary TB
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In newborns or immunosuppresed infection is not contained by CMI
Progressive primary -> pneumonia Miliary -> disseminates through blood to all sites |
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Where is recrudescent TB most commonly found?
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Lung apex
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TB path
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Caseating necrotizing granulomas w/ giant cells
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TB clinical presentation 5
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Cough, fever, night sweats > 3 wks
Weight loss Hemoptysis Apical cavitary lung lesions |
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Extrapulmonary TB in HIV
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Hilar lymphadenopathy
Pleural effusions Rarely miliary disease |
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Contrast atypical mycobacteria to TB (encounter, virulence, PPD, drugs)
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Atypical: from environment, lower virulence, usually neg PPD, not the same as TB
TB: human to human, virulent, PPD pos, TB drugs |
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TB drugs: primary vs secondary resistance
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Primary - bug already resistant pre therapy
Secondary - resistance develops during therapy |
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1st line TB drugs and early bacteriocidal activity
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Rifampin
Isoniazid Ethambutol Pyrazinamide I > E > R > P So treat with INH immediately |
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Isoniazid (moa, activity, 2 tox 1 antidote)
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1st line TB
Inhibits mycolic acid synth Activity depends on host acetylation speed Tox: neuro and hepato, rx neurotox w/ pyroxidine B6 |
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Rifampin (moa, 3 tox)
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Inhibits DNA-dependent RNA pol
Tox: hepatic, induces P450, stains contact lens orange |
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Pyrazinamide (use, activity, 2 tox)
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Anti TB
Active in acid pH (macrophage phagolysosomes) Tox: hepatic, uric acid |
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Ethambutol (use, 1 tox)
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Anti TB
Used to prevent resistance developing to other drugs Tox: retrobulbar neuritis |
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MDR TB (which drugs?)
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Resistant to at least INH and Rifampin
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XDR TB (which drugs?)
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MDR TB (INH and rifampin) + kanamycin, amikacin or capreomycin plus any fluoroquinolone
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Honey crusts, vesicles, pustules (2 pathogens)
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Impetigo
S. pyo S. aureus |
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Papules and pustules around hair folliculitis (2 pathogens)
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Folliculitis
S. aureus Pseudomonas |
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Tender, fluctuant mass w/ overlying erythema (2 pathogens)
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Abscess
S. aureus Non TB mycobacteria |
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Painless erythematous target like (1)
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Lyme
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Pustules w/ ulceration extending along lymphatic drainage channel
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Sporothrix "Rose Gardener's Disease"
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Umblicated skin lesion
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Cryptococcus or molluscum
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