Pulmonary Infections Microbioligy Flashcards
(54 cards)
Rhinovirus?
+ssRNA, icosahedral capsid, phrayngitis (common cold)
Influenza virus
acute, rapid onset of fevers, chills, malaise
leaves resp tract vulnerable to secondary infections
Types A, B, and C; a does genetic shift and drift, B does drift, C is stable, has hemagluttenin (H) and neuraminidase (N) whcih are necessary antigens for entering and exiting host cell
replication is pH-dependent (low pH of endosome does necessary H protein dissassembly)
shift is reassortment of viral genome strands, drift is mutation (corresponds to pandemic and epidemic)
M2 ion channel causes envelope dissassembly in endosome, inhibited by amantadine and rimantidine
neuraminidase releases virus, inhibited by -mavir antivirals
vaccins: attenuated virus is flu mist
Respiratoy Syncitial virus
most common cause of atypical pneumonia in infants
(remember, atypical pneumonia looks more like upper respiratory infection and causes interstial pneumonia, as opposed to lobar and bronchial with typical; atypical is caused by viruses and mycolasma and chlamydia; symptoms suggest URI, but URI looks normal on PE)
-ssRNA
DX with ELISA
no vaccine
Adenovirus
large, non-enveloped icosahedral with spikes and dsDNA
causes red eye and ARDS
usually infects
temporal replication in the nucleus
virulence factor: inhibits MHC-1
Eppstein barr virus
is a Herpes virus
replicates inside B cells nucleus
can present with swollen cervical lymph nodes, fatigue
lab: Heterophil antibody
can cause Burkitt’s lymphoma
cytomegalovirus
atypical pneumonia in the immunosuppressed (like AIDS, immunosuppressant therapy)
the bugs are visible only with GMS (a silver stain)
wide variation of morphology and presentation
staph aureus
G+, catalase +, coagulase+, B hemolytic
does CAP–bronchopneumonia
most common cause of secondary pneumonia
can form abscesses or empyema
what’s catalse+ and what’s catalase- between strep and staph?
staph is cat+, sterp is cat-
staph epidermidis
G+, cat+, coag-
post-surgical or puncture wound
can cause endocarditis
strep pyogenes (group a strep)
G+, cat-, coag-, B hemolytic, bacitracin sensitive, M protein
does pharyngitis, rheumatic fever, scarlet fever
treat with penicillin
strep viridans (note: not respiratoy infection, more endocarditis)
G+, cat-, A hemolytic, optochin resistant, bile resistant
causes endocarditis after dental work
strep pneumoniae
G+, cat-, encapsulated, A hemolytic, optochin sensitive, bile soluble, diplococci
mucoid colonies (glistening with mucous)
virulent capsule prevents C3b deposition
autolytic enzymes cleaves its own envelope in bile salts to make it bile soluble
***most common cause of lobar pneumonia, causes meningitis in children***
vaccine is a conjugate vaccine (protein and polysaccharide) for infants, just polysaccharide for immune-compromised
enterococci (note: not resp infection agent)
G+, cat-, Y hemolytic, bile resistant, salt tolerant, hydrolyzes esculin
can do endocarditis when there’s GI issues (like regurg), and UTI’s (urinary tract infection)
Mycobacterium tuberculosis
doesn’t gram stain though it’s technically G+, needs acid-fast stain
grows slowly on culture
test: PPD test (aka Monteaux skin test) of >15mm for normal patient, >5mm for immunocompromised, and adenosine deaminase testing
seeds into macrophages, do exponential growth, T cells activate and form granulomatous Ghon complexes
reactivation happens with immunocompromise
often forms lower lobe lesions in rpimary disease
reactivated disease has lesions at lung apices
E. coli
G-, rod, lactose+, p fimbriae
causes UTI’s, acute pyelonephritis
proteus mirabilis
rod, lactase-, oxidase-, urease-
chronic or repeat UTI’s with increased chance of calculi
haemophilus influenzae
G-, coccobacilli, encapsulated
grows on chocolate agar
causes bronchopneumonia, often 2nd to flu virus
conjugate vaccine
pneumonia on COPD, epiglottis infections
legionella
G-, rod, faculatative anaerobe, growns on buffered charcoal yeast agar
doesn’t G stain well, prevents phagosome and lysosom fusion, makes biofilms like a professional
lives intracellularly in amoebas
lives on metallic, aquatic environments
test: urine ELISA for LPS
community-acquired, immunocompromised, see with silver stain, can do some severe pnuemonia
chlamydia
G-, obligate intracellular pathogen which doesn’t stain well
does atypical pneumonia (interstitial)
2nd most common cause of atypical pneumonia in young adults
can get chlamydia psicatti–a chlamydia bug from birds
elemenatry bodies: infectious form, small and dense
reticular bodies, non-infectious, larger replicating form
what causes atypical pneumonia?
mycoplasma pnuemonia, chlamydia, viruses
Pseudomonas aeruginosa
G-, bronchopneumonia in cystic fibrosis and burn patients, encapsulated rods, oxidase+, lactase-, flagellated
green pigment, fruity smell, biofilms
Klebsiellae pneumonia
G-, lobar pneumonia, encapsulated, urease
Mucoid colonies, red currant jelly sputum
nosocomial infection, or aspiration (like alcoholics)
nosocomial UTI’s
Mycoplasma pneumonia
no cell wall so no gram stain (remember, G+ is purple and G- is pink so no G stain is no color, CARDS toxin
most common cause of atypical pneumonia in young adults, especially military
histoplasma capsulatum
dimorphic fungus, bird and bat excreta in ohio and mississippi river valleys
same pathogenesis as TB, can cause cardiac tamponade
dx with antigen test on serum
