Microbiology CasesOrganismFeaturesHost ResponseClinical PresentationDiagnosisTreatmentStreptococcus pneumoniae(pneumonia)•#1 cause community-acquired pneumonia•gram +, catalase -, bullet shaped diplococcus•capsule = most important virulence factor•spread via resp droplets•secretory IgA•pneumonia (sudden-onset, fever, productive cough, +/- blood in sputum)•common cause of sinusitis & otitis media•complications = bacteremia & meningitis•gram stain •culture: small/medium mucoid colonies w/alpha hemoloysis, optochin succeptible, bile succeptible •antigen test•penicillin •if pen-resistant ceftriaxone or clindamycin•7-valent vaccine for children!Neisseria Meningiditis(meningitis)•one of the usual suspects for meningitis (S. pneumo, N. meningiditus, H. flu….GBS in neonates)•capnophillic, gram – cocci in pairs (coffee-bean shaped)•has LOS instead of LPS •meningitis belt in sub-Saharan Africa •complement and Ig’s•meningococcemia can start with flu-like sx, then petichial rash•then pustules, bullae…•sepsis DIC in a matter of hours•+/- meningitis (HA, neck stiff, altered mental state, vomiting)•gram stain•culture (prefers chocolate agar)•penicillin G or ceftriaxone ASAP•tetravalent vaccine (polysaccaride capsular protein conjugate) for serotypes: A, C, Y, W135* no coverage for serotype B
Salmonella typhi (Typhoid fever)•motile gram – rods•strictly human dz, spread thru contaminated food/water•typhi enters thru GI and disseminates thru blood. •Non-typhoid salmonellas (typhimurium and enteritidis) stay in GI and cause enterogastritis)•risk if immunocomp or sickle cell dz•typhi: survives in Φ’s by messing with phagolysosome fusion distrib to organs and get organ-specific dz.•non-typhi: stays in GI, get GI dz, granulocyte responseTyphoid fever•present with fever of unknown origin (“PUO”). Fever, HA, ab discomfort, const or diarrhea…•+/- bradycardia, “rose spots,” and hepatosplenomegaly•+/- anemia and leukopenia•complications: cholecystitis, endocarditis, osteomyelitis•~5% of ppl carriers (typhoid Mary)Non-typhoid salmonella•self-limited diarrhea •12-48 hr incubation•isolate and ID the organismTyphoid fever•ampicilling, cipfofloxacin, or chloramphenicol•vaccine-preventable (says in case but I’ve never heard of it)non-typhoid salmonella•support & fluidsE. coli(UTI)•UTI most often caused by E. coli. Other suspects are proteus, staph. Saprophyticus (young sexing woman), and pseudomonas (hospital) •E. coli is gram – rod with peritrichous flagella and LPS•UTI caused by normal bowel flora & more in women bc short urethra •E. coli adheres to epithelial cells & prods toxin•protected from host immune by K1 capsular antigen•IgA and IgG prod•cystitis (normal UTI): frequency of urination, dysuria (painful pee), and abdominal tenderness•pyelonephritis (up to kidney): loin pain, fever, and above sx•complications: septicemia, renal scarring failure
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Term
Spring
Professor
staff
Tags
Sickle cell dz, rash bc rash, ppl fever
