Bacterial pneumonia Flashcards
Strep pneumoniae patho
#1 CAP, #1 bact meningitis in adults, #1 otitis media in children
S. pneumoniae morpho
G+ lancet or diplococci blood agar --> alpha hemolytic lysed by bile catalase - optochin sensitive
S. pneumoniae virulence
Polysaccharide capsule
IgA protease
Pneumolysin –> pore forming toxin sim to Strep O
S. pneumoniae CP
acute chills, fever, SOB
rusty sputum with inflammatory cells (neutrophils) and organism
pleuritic chest pain with rales
will see lobar consolidation
S. pneumoniae Dx and Tx
gram stain of smear culture latex agglutination of CSF pos Quellung Rxn host prod anti-capsular IgG --> activation of classical C' Tx with PCN
Klebsiella pneumoniae morpho
G- rod oxidase - lactose fermenter pos Quelung test pink colonies on MacCokney agar
Klebsiella pneumonias vir and patho
antiphago polysacch capsule endotoxin necrotizing pneumonia --> currant jelly sputum common in aspiration pneumonia diabetics and alcoholics susceptible nosocomial UTIs
Peudomonas aeruginosa morpho
G- rod aerobic motile oxidase + catalase + nonlactose fermenter sec blue-green pyocyanin pigment "fruity" odor
P. aeruginosa vir
Exotoxin A –> ADP ribosylation of EF-2
endotoxin
proteolytic enzymes and capsular slime
P. aeruginosa patho
nosocomial infections –>indwelling catheters and BURN victims
pneumonia in CF patients
osteomyelitis in diabetics
Mycoplasma pneumoniae morpho
no cell wall ; triple layer of membrane with sterols
extracellular
fried egg appearance
grows on media with lipoprotein and sterols (Eaton’s agar)
completely resistant to cell wall synth inhib antibio
Mycoplasma pneumoniae epid
droplet xsmission
primary atypical pneumonia –> “walking pneumonia”
teens and pre-teens and military recruits
Mycoplasma pneumoniae patho
damages resp epith –> inflammation of bronchial, peribronch, and alveoli
insidious onset w/ non prod cough
patchy infiltrate with consolidation
Mycoplasma pneumoniae Dx and Tx
serology is more efficient than culture
cold agglutinin titer
tx with doxy or erythromycin
Legionella pneumophila morpho
G-; stains poorly grow on charcoal yeast media with iron and cysteine (BCYE) catalase + oxidase + facultative intracellular silver stain
Legionella pneumophila epid
warm and water sources
no PTP xsmission
can also live in biofilms
older men who smoke and drink at higher risk
Legionella pneumophila patho
acute ulcerative bronchitis, bronchiolitis, and confluent pneumonia may form abscesses lesser form: Pontiac fever worse form: Legionaire's dz Dx via culture or serology (serotype 1)
L. pneumophila Dx and Tx
Dx via culture or serology (serotype 1)
Tx with macrocodes and fluoroquinolones
Chlamydophila pneumoniae
obligate intracellular
cell walls resemble G- but lack muramic acid
atypical pneumonia resembling mycoplasma
airborne xsmission
Chlaydophila pneumoniae life cycle
elementary body (spore-like) –> reticulate body in cells –> divide by binary fission –> inclusion body
Tx with tetracycline and erythromycin
Dx with 1:16 titer
Chlamydophila psittaci
psittacosis or ornithosis obligate intracellular cell walls resemble G- but lack muramic acid non prod cough, rales, consolidation get form BIRDS
Coxiella Burnetii
Q fever --> febrile resp dz rickettsia family --> but NOT xsmit by arthropods obligate intracellular no rash neg Weil-Felix rxn xsmit by cows
