Final Flashcards
Acute Pneumonia - community acquired –> which bugs?
S. pneumoniae
H. influenza
Influenza virus
Acute pneumonia - nosocomial –> which bugs?
Staph aureus
gram negatives
Acute pneumonia - opportunistic –> which bugs?
pseudomonas pneumocystis CMV adenovirus herpes
Acute stage of pneumonia
polys in alveoli
macrophages later
Resolving stage of pneumonia
polys gone
many macrophages
infiltrates are cleared
alveolar walls intact
Organizing stage of pneumonia
granulation tissue in terminal bronchioles & alveoli
fibrosis
What are the stages of pneumonia?
Acute –> resolving –> organizing
What is the typical causative organism for lobar pneumonia?
Strep pneumoniae
Which 2 spots is aspiration pneumonia most likely to settle?
Posterior segment of upper lobe
Superior segment of lower lobe
What is used to ID the legionella bacteria?
Dieterle silver stain
When would you see prominent basophilic inclusions?
Atypical pneumonia caused by adenovirus
When would you see prominent eosinophilic nuclear inclusions?
Atypical pneumonia caused by herpes simplex virus
When would you see both nuclear AND cytoplasmic inclusions?
Atypical pneumonia caused by CMV virus
When would you see oval-crescentic GMS+ cysts?
Pneumocystis jiroveci (carinii) pneumonia
When would you see an abundance of plasma cells in the alveolar walls?
Pneumocystic jiroveci (carinii) pneumonia
When would you see a gram stain with lots of WBCs but no organisms?
Legionella pneumonia
What would you think if the patient isn’t responding to “conventional” antibiotics?
Could be legionella pneumonia, esp if the cultures don’t reveal a pathogen
What is the best way to diagnose legionella? Be specific.
Culture!
-use BCYE –> buffered charcoal yeast extract, supplemented & made selective
When would you see a bullous otitis media?
Mycoplasma infection
Spherules are pathognomonic of what?
Coccidiodes immitis (dimorphic fungi)
Where is Coccidiodes immitis endemic?
Southwest US
Where is Histoplasma capsulatum endemic?
Central US
What is the mechanism of action of amphotericin B?
Binds to Ergosterol (the primary fungal cell membrane sterol)
Direct toxicity to cell membrane –> punches holes in it, making it more leaky
What is the mechanism of action of azoles?
Inhibits the cytochrome P450 which converts lanosterol to ergosterol (the primary fungal cell membrane sterol)
Interferes with cell membrane synthesis
In general, uses of fluconazole?
Active against yeasts, NOT against molds
what is the mechanism of action of echinocandins?
inhibit the fungal beta(1,3)-glucan synthase
depletes beta-glucan, a ubiquitous fungal cell wall constituent
Dirty pneumonia
adenovirus
Etiology of otitis media
Streptococcus pneumoniae - 35-40%
Nontypable H influenzae - 25-30%
Moraxella catarrhalis - 15-20%
Spread of Hib v. NTHI
Hib spreads through hematogenous means
NTHI spreads locally
Hib v. NTHI evolutionary history
Hib is clonal
NTHI is genetically diverse
Causative pathogens for COPD exacerbations
H. influenzae > Moraxella catarrhalis > Strep pneumoniae > Pseunomonas aeruginosa
Strep pneumoniae v. other viridans strep
Strep pneumoniae is optochin sensitive
Other viridans strep are optochin resistant
Mechanism of strep pneumoniae intermediate penicillin resistance
transformation with penicillin binding protein genes from closely related species
Mechanism of strep pneumoniae high level penicillin resistance
trasformation with penicillin binding proteins genes from closely related species
+ spontaneous mutations
Rx for penicillin suceptible pneumococcal pneumonia
penicillin
cephalosporins
fluoroquinolones
Rx for penicillin resistant pneumococcal pneumonia
penicillin (high doses) cephalosporins fluoroquinolones vancomycin linezolid
What bug might you see after the use of a lot of carbapenems?
Stenotrophomonas maltophilia
First choice drug for Pneumocystis jiroveci (Pneumocystis carinii)
Trimethoprim-sulfamethoxazole
most common extrapulmonary site for nocardia infection
Brain
Primary treatment for nocardia infection
Sulfonamides
Ecthyma gangrenosum is strongly associated with which infection?
Pseudomonas aeruginosa
What infections do you see with terminal complement deficiencies (C6-C9)?
Neisseria, esp Neisseria meningitidis
Treatment of lung abscess
Clindamycin
Lung abscess characterized by what?
Foul-smelling sputum
history of poor dentition & loss of consciousness
Treatment of allergic bronchopulmonary aspergillosis
Itraconazole (antifungal) + steroid
What is the mechanism of action of terbinafine (lamisil)
inhibits squalene epoxidase, an enzyme involved in ergosterol synthesis
What is the major use of flucytosine?
in combination with amphotericin B for cryptococcal meningitis
What is the mechanism of action of flucytosine
inhibits fungal protein synthesis by replacing uracil with 5-flurouracil in fungal RNA (& also interferes with fungal DNA synthesis)
Major flucytosine toxicities
bone marrow suppression & GI toxicity
How to culture mycobacterium
Does NOT grow on routine lab media
grow in lowenstein-jensen agar
