Microbiology - Exam 2 Flashcards
Respiratory Microbes GI Microbes
Escherichia coli on MAC (MacConkey agar)
flat, pink colonies
E. coli on Xylose Lysine Deoxycholate agar (XLD agar)
yellow
E. coli on Hektoen Enteric (HE) Agar
orange
E. Coli on BAP
positive
E. coli on Bile Esculin Agar (BEA)
negative
Enterobacter sp. on MAC (MacConkey agar)
mucoid, pink colonies
Enterobacter sp. on Xylose Lysine Deoxycholate (XLD agar)
yellow
Enterobacter sp. on Hektoen Enteric (HE) Agar
orange
Enterobacter sp. on BAP
positive
Enterobacter sp. on Bile Esculin Agar (BEA)
negative
Enterococcus sp. on Bile Esculin Agar (BEA)
positive showing black agar
Lactose positive on MAC (MacConkey agar)
pink
Lactose negative on MAC (MacConkey agar)
clear
Lactose positive on Xylose Lysine Deoxycholate agar (XLD agar)
yellow
Lactose negative on Xylose Lysine Deoxycholate agar (XLD agar)
red
Lactose positive on Hektoen Enteric (HE) Agar
orange
Lactose negative on Hektoen Enteric (HE) Agar
green
What organism causes symptoms that are sometimes confused with those of appendicitis?
Yersinia enterocolitica
Which of the following is not true of Clostridium difficile?
A. It is a common pathogen following prolonged antibiotic therapy
B. Toxin B agglutination is the test for C. diff
C. It is an opportunist and part of the normal GI flora
D. It can cause pseudomembranous colitis and perforate the bowel if it reaches high numbers
B. Is false Clostridium difficile produces two toxins that cause the colitis….Toxin A and Toxin B. We have an agglutination (clumping) test to detect Toxin A.
Which form of E. coli produces chronic diarrhea due to inflammation of the colon, but it doesn’t invade the mucosa?
Enteroaggregative E. coli
What organism is thought to be a possible cause of Guillain-Barre syndrome?
Campylobacter jejuni
What bacteria can cause HUS (Hemolytic Uremic Syndrome?)
E. coli 0157-H7
What organism is associated with food poisoning from meat, processed meat (such as cold cuts) and milk?
Listeria monocytogenes – need to re-heat all meat that has been refrigerated, as Listeria can survive freezing temperatures.
What GI pathogen can cause death by flaccid paralysis?
Clostridium botulism
What is the most common species of Salmonella?
Salmonella typhimurium
This organism produces toxins causing watery diarrhea and a huge loss of electrolytes. It is known as “Traveler’s Diarrhea.” What is it?
Enterotoxogenic E. coli
What bacteria can cause pseudomembranous colitis?
Clostridium difficile
Which of the following is false concerning Vibrio cholera?
Very short incubation period Causes small amount of fluid loss in diarrhea Associated with water Transmitted via fecal-oral contamination No vaccine is available
B & E are falseB. Cholera causes huge fluid loss due to enterotoxin produced by the bacteria that causes salt (electrolytes) and water to be secreted from infected cells. Death can occur within 6 hours. E. The World Health Organization is involved in monitoring cholera epidemics. Vaccine is required for travel to some countries. The vaccine is only 50% effective and only provides immunity for 6 months.
What bacterial organism causes illness that is treated with antitoxin to prevent further binding of the toxin?
Clostridium botulism
What organism is shed from the GI tract in the feces of animals?
Salmonella sp.
What organism is found as a pathogen in 80% of chickens?
Campylobacter jejuni
Which form of E. coli produces profuse, watery diarrhea?
Enteropathogenic E. coli
What two pathogenic organisms need very few numbers to infect?
Clostridium botulism
Shigella dysenteriae
Which 7 bacteria that we have studied are normal flora of the GI tract, but are opportunists and can become pathogenic if numbers increase sufficiently?
Bacteroides sp. Clostridium sp. E. coli (most strains) Enterobacter sp. Enterococcus sp. Proteus sp. Pseudomonas sp.