Micro 2 USMLE Flashcards
dermatophyte has a reservoir in pets
microsporum
this obligate anaerobic bacilli is gram positive, spore forming
clostridia
this clostridium species produces an exotoxin
clostridium tetani
C tetani exotoxin works by blocking ________ release [inhibitory neurotransmitter] from Renshaw cells in the spinal cord
glycine
this clostridia bacilli forms a preformed, heat-labile toxin that inhibits ACh release
C. botulinum
mneu: BOTulinum is from bad BOTtles of food (causes a flacid parralysis)
this clostridia bacilli produces an alpha toxin (lethinasse) that causes myonecrosis, gas gangrene, or hemolysis.
C. Perfringes
mneu: PERFringes PERForates a gangrenous leg
this clostridia bacilli produces a cytotoxin, an exotoxin that kills enterocytes, causing psudomembranous colitis. It is often secondary to antibiotic use, especially clindamycin or ampicillin.
C. difficile
mneu: DIfficile causes DIarrhea.
how do you tx C. difficile
metronidazole.
Diptheria is caused by _________ via exotoxin encoded by a Beta-prophage.
Corynebacterium diptheriaee
the potent diptheria exotoxin works by inhibiting what via ADP ribosylation of EF-2
Protein synthesis
coryne=______
club shaped
Symptoms of infection with this bug include pseudomembranous pharyngitis (grayish-white membrane) with lymphadenopathy)
C. diptheriae.
C diptheriae identified in the lab as a Gram ___, _____ with metachromatic ranules.
G+, rod
C diptheriae grows on a ______ agar
tellurite
What are the ABCDEG of diptheria and its exotoxin
ADP ribosylation Beta-prophage Corynebacterium Diphtheriae Elongation Factor 2 Granules
pt presents with painless black skin lesions (vesicular papules covered by black eschar). He developes sepsis and dies. What G+ sporeforming rod that produces a toxin do you suspect
Bacillus anthracis
Inhalation of anthrax spores from contaminated wool can lead to flulike symptoms that rapidly progress to fever, pulmonary hemorrhage, and shock. what is the name of this dz.
woolsorters dz.
these two bugs are both gram + rods forming long branching filaments resembling fungi
actinomyces v. nocardia.
this bug forms yellow “sulfur granules’ in sinus tracts
A. israelii
this bug is a G+ ANAEROBE, that causes oral/facial abscesses with “sulfur granules” that may drain through sinus tracts in the skin. It is part of the normal oral flora.
Actinomyces israelii
this bug is a gram + and weakly acid fast aerobe in the soil taht causes pulmonary infection in immunocompromized pts
Nocardia asteroides
How do you tx nocardia? actinomyces?
mneu: SNAP Sulfa for Nocardia; Actinomyces use Penicillin
Gram negative outer membrane layer inhibits entry of these 2 AB. Therefore G - bugs are resistant to these 2 drugs
Penicillin G
Vancomycin
T or F. G- bugs are resistant to all derivitives of penicillin such as ampicillin
F–just resistant to PCN & Vanco.
Neisseria is a gram ___, ____
neg, cocci
Neisseria Gonococci or Meningococci?
Polysaccharide capsule
Meningococci
Neisseria Gonococci or Meningococci?
No Polysaccharide capsule
Gonococci
Neisseria Gonococci or Meningococci?
No maltose fermintation
Gonococci
Neisseria Gonococci or Meningococci?
maltose fermintation
Meningococci
Neisseria Gonococci or Meningococci?
No Vaccine
Gonococci
Neisseria Gonococci or Meningococci?
Vaccine
Meningococci
Neisseria Gonococci or Meningococci?
causes gonorrhea, septic arthritis, neonatal conjunctivitis, PID
Gonococci
Neisseria Gonococci or Meningococci?
causes meningococcemia and meningitis, Waterhouse-Friderichsen syndrome
Meningococci
this bug is a small gram negative (coccobacillary) rod spread via aerosol transmission.
Haemophilus influenzae
HaEMOPhilus Influenzae causes (4)
Epiglottis, Meningitis, Otitis media & Pneumonia.
Most invasive form of H. influenzae is caused by capsular type ___
B.
H. influenzae produces ____ protease.
IgA.
how do you culture H. influenzae
chocolate agar w/ factors V (NAD) & X (hematin) for growht
mneu: when child has “flu” mom goes to five(V) & dime (X) to buy some chocolate.
H. flu vaccine contains type B capsular polysaccharide conjugated to diptheria toxoid or other protien. It is given between ____ and _____ mo of age.
2 and 18
this group is a diverse family including E. coli, salmonella, shigella, klebsiella, enterobacter, serratia, porteus
enterobacteriaceae.
all enterobacteriaceae have somatic (__) Ag (polysaccharide of endotoxin. The capsular (__)Ag related to virulence of the bug. The flagellar (__) Ag is found in motile species
O
K
H
enterobacteriaceae ferment ____ and are oxidase ____
glucose
negative
with enterobacteriaceae think COFFEe.
Capsular O Ag Flagellar Ag Ferment glucose Enterobacteriaceae
these bacteria grow pink colonies on MacConkey’s agar. Examples include Klebsiella, E. coli, Enterobacter, and Citrobacter
Lactose fermenters
Lactose is KEE
These 2 organisms are similar in that both are non-lactose fermenters. Both invade intestinal mucosa and can cause bloody diarrhea
Salmonella v. Shigella
Salmonella v. Shigella:
Only _______ is motile and can invade further and disseminate hematogenously. Symptoms may be prolonged with AB treatments, and there is typically a monocyte response.
Salmonella
mneu: Salmon swim (motile and disseminate
_____ has an animal reservoir
salmonella.
Shigella is transmitted via the 4 Fs
Food, fingers, feces, & fliies
usually transmitted from pet feces (e.g., puppies), contaminated milk, or pork. Outbreaks are common in day-care centers. Can mimic Crohn’s or appendicitis, can disseminate to produce lymphadenitis.
Yersinia enterocolitica.
Bugs causing food poisoning:
contaminated seafood
Vibrio parahaemolyticus & V. vulnificus
Bugs causing food poisoning:
reheated rice
Bacillus cereus
Bugs causing food poisoning:
meats, mayonaise, custard
s/s starts quickly and ends quickly
S. aureus
Bugs causing food poisoning: reheated meat dishes
clostridium perfringes
Bugs causing food poisoning: undercooked meat
E. Coli O157:H7
Bugs causing food poisoning: poultry, meat, & eggs
Salmonella
Pt presents with bloody diarrhea. culture shows comma or S- shaped, oxidase positive organisms that grow at 42*C. What is the species
Campylobacteria
Pt presents with bloody diarrhea. culture shows motile organisms What is the species
Salmonella
Pt presents with bloody diarrhea & dysentery. Culture shows nonmotile species with very low ID50. What is the species
Shigella.
What is more virulent Shigella or Salmonella
Shigella (only 100 organisms causes dz)
Pt presents with bloody diarrhea which progresses to HUS. culture shows shiga-like toxin. What is the species
Enterohemorrhagic E. coli
Pt presents with bloody diarrhea. culture shows O157:H7 which has invaded the colonic mucosa What is the species
Enteroinvasive E. coli
child at day care center presents with bloody diarrhea and pain that mimicks appendicitis. What is the bug?
Yersinia enterocolitica
Pt presents with bloody diarrhea & pseudomembranous colitis. What is the species
C. dificile
Pt presents with bloody diarrhea. culture shows protozoa. What is the species
entamoeba histolytica
Pt presents with watery diarrhea. Hx of traveling out of the country. No preformed toxin. What is the species
Enterotoxigenic E. coli (ETEC)
Pt presents with rice watery diarrhea . culture shows comma shaped organisms. What is the species
V. cholerae
Pt presents with watery diarrhea and gas gangrene. What is the species
C. perfringes
Immunocompromized pt presents with watery diarrhea. what do you suspect.
protazoa (e.g., giardia, cryptosporidium)
Pt presents with watery diarrhea . What viruses could cause this
Rotavirus, adenovirus, Norwalk virus