Microbio 4 Flashcards
UTI
[MCC, Px]
MCC: E. coli
>E. coli is part of normal GIT flora – has fimbriae that allow it to colonize and ascend urinary tract.
>UTI are MCC of E. coli bacteremia.
Staph food poisoning vs. B. cereus food poisoning
> Staph food poisoning: preformed heat-stable endotoxin, mayonnaise-containing foods (potato and mac salad).
B. cereus food poisoning: preformed heat-stable exotoxin, starchy foods like rice (reheated fried rice).
HSV-1 gingivostomatitis vs. Coxsackievirus hand-foot-mouth dse.
Lesions found on what parts?
> HSV-1: lip lesions, hard palate, gums, lymphadenopathy.
>Coxsackievirus: buccal mucosa, soft palate, tongue
Achalasia
[Cause, Px]
For patients from Central/South America, suspect Trypanosoma cruzi.
>Neurotoxin destroys myeneteric plexus – denervates esophageal smooth muscle, LES – proximal dilated esoph (ex. Chagas disease)
>May affect sigmoid colon, ureter – megacolon, megaureter
Why doesn’t infection w/ N. gonorrhoeae result with lasting immunity?
Bacteria can modify outer membrane proteins via antigenic variation (Pilus variation) – antibodies specific only to one epitope.
Campylobacter jejuni
[Disease, association]
MCC of acute gastroenteritis in industrialized countries.
>Inflammatory diarrhea (watery, then bloody)
>From domestic animals (dogs, cattle, chickens, sheep) or contaminated food
>MC infectious agent assctd w/ GBS
Lung abscess
[Cx of what, bacteria, ssx]
Cx of Aspiration pneumonia, abscess caused by anaerobic bacteria of Oral cavity (Bacteroides, Fusobacterium, Peptostreptococcus).
>Productive cough w/ greenish, foul-smelling sputum; takes weeks for cavitary lesion to form.
How is bacterial Pneumonitis caused? Ssx? Bacteria involved?
Aspiration of Stomach contents, may present Hours after event (vs Lung abscess) – inflammation, not infection.
>Nonproductive cough, infiltrates can resolve w/o antibacterials.
>Most important pathogen of stomach: H. pylori.
In AIDS patients, how do you determine if CAP is caused by S. pneumoniae or P. jirovecii?
In immunocompetents, MCC of CAP is S. pneumoniae, and AIDS pts w/ CAP likely have P. jirovecii.
However, if AIDS pt is not yet immunocompromised (CD4+ less than 200 cells/mL), then cause is likely S. pneumoniae.
Immortalization of B cells? Viral cause?
EBV infects B cells, stimulating them to proliferate continuously (transformation, immortalization).
EBV is an oncogenic virus – polyclonal B cells proliferate w/ heterophile antibody prodn.
Strongyloides
[Dx, findings]
> Dx: Rhabditiform (noninfectious) larva in stool.
Presents w/ GI or pulmo problems (feels like a peptic ulcer) – vomiting, diarrhea, epigastric pain.
Pruritic erythematous linear streaks (larva currens) along thighs and buttocks – larvae migrating away from perianus.
Infant botulism
Infant consumes spores (honey) – germinate in GIT – toxin released w/ systemic absorption.
>Constipation, then neuromuscular paralysis (floppy baby)
