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Gram Negative Bacilli-Enterics
Exam 2
133
Pharmacology
Professional
05/01/2011

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Term
basic characteristics of enterobacteriaceae
Definition
all ferment glucose and are catalase negative
Term
most common fecal microorganism
Definition
Bacteroides fragilis
Term
Bacteroides fragilis is aerobic/anaerobic.
Definition
anaerobic
Term
What color does EMB media turn in the presence of a lactose fermenter?
Definition
purple to black to metallic sheen
Term
What color does McConkey agar turn in the presence of a lactose fermenter?
Definition
pink-purple
Term
Methylene blue inhibits...
Definition
gram pos organisms growth
Term
What in McConkey agar inhibits the growth of gram pos organisms?
Definition
bile salts
Term
most important lactose fermenter
Definition
E. coli
Term
most important lactose non-fermenters
Definition
Shigella
Yersinia
Salmonella
Vibrio
Term
What is the clinical significance of fecal leukocytes and blood in the stool?
Definition
distinguishes invasive bacteria from toxigenic bacteria
Term
invasive enteric bacteria that is gram neg, non-motile, non-lactose fermenter, does not produce H2S
Definition
Shigella
Term
How is Shigella transmitted?
Definition
fecal-oral route
Term
Shigella invades the intestinal epithelium and may progress to a _________ __________.
Definition
mucosal ulceration
Term
Why is Shigella so efficient in its transmission?
Definition
very small inoculum (10-200 organisms) is sufficient to cause infection
Term
Shigella readily occurs in what type of settings?
Definition
where hygiene is poor
Term
How long are Shigella organisms present in an infected individual?
Definition
while they are ill and for 1-2 weeks afterwards
Term
What population is especially susceptible to getting Shigella?
Definition
toddlers who are not fully toilet-trained
Term
Shigella edidemics may be _______ or _________.
Definition
foodborne; waterborne
Term
What insect can transmit Shigella?
Definition
flies
Term
bacteria responsible for causing bloody diarrhea with fecal WBCs and many ulcerations within the colon
Definition
Shigella flexneri
Term
Shiga toxin inhibits...
Definition
protein synthesis (which destroys the epithelium)
Term
rice water stools with fishy odor
Definition
Vibrio cholera
Term
What bacteria can be contracted by eating raw oysters and sushi?
Definition
Vibrio cholera
Term
gram neg, curved bacillus, lactose non-fermenter, oxidase positive
Definition
Vibrio cholera
Term
incubation period for Vibrio cholera
Definition
<1 day-5 days
Term
What enteric bacteria produces an enterotoxin that causes a copious, painless, watery diarrhea that can quickly lead to severe dehydration and death if treatment is not promptly given?
Definition
Vibrio cholera
Term
Shigella is oxidase negative/positive.
Definition
negative
Term
Vibrio is oxidase negative/positive.
Definition
positive
Term
Salmonella is oxidase negative/positive.
Definition
negative
Term
transmission of Vibrio cholera
Definition
fecal-oral route
contaminated shellfish
Term
What causes the dramatic watery diarrhea associated with Vibrio cholera?
Definition
cholera enterotoxin induces active influx of water and ions into the lumen of the colon
Term
If untreated, Vibrio cholera may progress to...
Definition
hypovolemic shock due to severe dehydration
Term
Acute, watery diarrhea is usually caused by a _________.
Definition
virus
(viral gastroenteritis)
Term
What bacteria causes the most common type of watery diarrhea in travelers?
Definition
E. coli (enterotoxin)
Term
Acute bloody diarrhea suggests a bacterial cause like...
Definition
Campylobacter
Salmonella
Shigella
Term
gram neg bacillus, glucose fermenter, catalase positive, oxidase negative that causes bloody diarrhea
Definition
enterohemorrhagic E. coli (EHEC)
Term
EHEC
Definition
enterohemorrhagic E. coli
serotype O157:H7
Term
transmission of O157:H7
Definition
undercooked ground beef
unpasteurized milk and juice
raw sprouts, lettuce
salami
contact with infected animals
Term
Shiga toxin-producing E. coli is a type of EHEC bacteria than can cause illness ranging from...
Definition
mild intestinal disease to severe kidney complications
Term
What is the only enteric bacteria that can be considered normal flora?
Definition
E. coli
Term
hemolytic uremic syndrome
Definition
occurs as a result of O157:H7 infection

anemia, renal failure, and thrombocytopenia
Term
three groups of diarrhea-producing E. coli
Definition
enterotoxigenic
enteroinvasive
enterohemorrhagic
Term
What type of E. coli is most common among infants and travelers in underdeveloped countries or regions of poor sanitation?
Definition
enterotoxigenic
Term
What bacteria accounts for 60% of traveler's diarrhea cases?
Definition
enterotoxigenic E. coli
Term
What does the toxin do that enterotoxigenic E. coli produces do?
Definition
activates adenylate and guanylate cyclase, causing secretory diarrhea
Term
What type of E. coli penetrates and multiplies within the epithelial cells of the colon causing widespread cell destruction?
Definition
enteroinvasive E. coli
Term
What type of E. coli causes a clinical syndrome identical to Shigella dysentery that includes a dysentery-like diarrhea with fever?
Definition
enteroinvasive
Term
mechanism of enterohemorrhagic E. coli (O157:H7)
Definition
-toxin acts on lining of the blood vessels and vascular endothelium
-killing of endothelial cells leads to breakdown of the vessel lining and to hemorrhage
-first response is bloody diarrhea
Term
transmission of enterotoxigenic E. coli (ETEC)
Definition
fecal-oral route
Term
What causes the watery diarrhea associated with ETEC?
Definition
-decreased reabsorption of Na and Cl
-increased secretion of Cl and HCO3 into lumen
-H2O follows osmotic load
Term
Which type of E. coli infection is associated with fever and abdominal pain?
Definition
enteroinvasive E. coli (EIEC)
Term
Which 2 types of media are used to inhibit gram positive bacteria and aid in the identification of the gram negative enterics?
Definition
EMB (Eosine Methylene Blue)
McConkey
Term
gram neg bacillus, facultative anaerobe, lactose non-fermenter, H2S producer, associated with chicken
Definition
Salmonella sp.
Term
most common Salmonella
Definition
Salmonella enteritidis
Term
Which enteric bacteria has an animal reservoir rather than human?
Definition
Salmonella (unless S. typhi)
Term
virulence factor for Salmonella typhi
Definition
capsule
Term
transmission of Salmonella enteritidis
Definition
raw eggs, unpasteurized milk
reptilian pets
poultry
Term
symptoms of Salmonella infection
Definition
nausea, vomiting, watery diarrhea, abdominal cramping
Term
What can Salmonella infection cause in patients with sickle cell disease?
Definition
osteomyelitis

due to functional asplenism and defective phagocytosis of encapsulated bacteria
Term
How long does Salmonellosis typically last?
Definition
self-limiting
2-5 days
Term
A person infected with Salmonella enteritidis usually has fever, abdominal cramps, and diarrhea beginning ___ to ___ hours after consuming a contaminated food or beverage.
Definition
12-72
Term
transmission of Campylobacter jejuni
Definition
unpasteurized milk and cheese
Term
What 3 enteric bacteria must be grown on special media (fastidious)?
Definition
Campylobacter
Yersinia
Vibrio
Term
symptoms of Campylobacter jejuni infection
Definition
abdominal discomfort, LLQ tenderness, greenish watery diarrhea (with or without blood)
Term
gram neg bacillus, slightly curved, microaerophilic, fastidious, oxidase positive, lactose non-fermenter, grows at 42 degrees Celcius
Definition
Campylobacter jejuni
Term
What is one of the most common causes of infectious diarrhea?
Definition
Campylobacter jejuni
Term
What causes the characteristic appearance of E. coli on EMB agar?
Definition
vigorous lactose fermentation causes the metallic sheen and acid production precipitates the green pigment
Term
other bacterial causes of traveler's diarrhea
Definition
other subtypes of E. coli (other than ETEC)

Shigella
Salmonella
Campylobacter jejuni
Vibrio
Term
protozoal causes of traveler's diarrhea
Definition
Giardia
Entamoeba histolytica
Cryptosporidium parvum
Term
viral causes of traveler's diarrhea
Definition
Norwalk virus
Rotavirus
Term
What is the predominant normal flora organism found in the small intestines and colon?
Definition
Bacteroides fragilis
Term
normal flora of the small intestines and colon (scant in small bowel)
Definition
-Bacteroides
-Clostridium sp.
-Escherichia
-assorted gram neg anaerobes (such as Fusobacterium--similar to Bacteroides)
Term
"friendly" bacteria in the intestine of humans
Definition
Bifidobacteria

gram pos, non-spore-forming, lactic acid bacteria
Term
What is the predominant bacterial species in the intestine of breastfed infants?
Definition
Bifidobacterium bifidum
Term
What bacteria are sometimes used in the manufacturing of yogurts and are frequently incorporated into probiotics?
Definition
Bifidobacterium
Term
What bacteria is a regular component of the intestinal flora that many European countries use as the standard indicator of fecal pollution, much like how we use E. coli in the US?
Definition
Enterococcus faecalis
Term
What enteric bacteria that is typically considered normal GI flora has recently emerged as a significant antibiotic-resistant nosocomial pathogen?
Definition
Enterococcus faecalis
Term
obligate anaerobe, gram neg bacillus, typically normal GI flora
Definition
Bacteroides fragilis
Term
most common fecal microorganism
Definition
Bacteroides fragilis
Term
What does Bacteroides fragilis cause?
Definition
necrosis
abscess formation
Term
gram negative bacillus, not enteric bacteria, but causes bacteria
Definition
Yersinia enterocolitica
Term
transmission of Yersinia enterocolitica
Definition
fecal-oral route
contaminated milk
fecally contaminated water
Term
mechanism of action for Yersinia enterocolitica
Definition
-binds to epithelium
-invades cells and regional lymph nodes
-releases enterotoxin that causes diarrhea
Term
symptoms of Yersinia enterocolitica infection
Definition
diarrhea with RBCs, WBCs
fever
abdominal pain (especially RLQ)
Term
What bacteria is microaerophilic but is not cultured, urease positive, and causes inflammatory changes leading to peptic ulcers in stomach and duodenum?
Definition
Helicobacter pylori
Term
How does H. pylori survive in the stomach?
Definition
creates ammonia
Term
If H. pylori is not cultured, how is it diagnosed?
Definition
visualized in tissue
urease breath test
serology
Term
What species of Clostridium is commonly isolated from feces?
Definition
Clostridium perfringens
Term
What bacteria may colonize the bowel and cause antibiotic-induced diarrhea or psudomembranous colitis?
Definition
Clostridium difficile
Term
What bacteria causes pseudomembranes in the colon?
Definition
Clostridium difficile
Term
How is C. diff usually diagnosed?
Definition
detection of bacterial toxin in the stool (not easily cultured)
Term
What antibiotics are most commonly associated with CDAD and C. diff infection?
Definition
broad-spectrum (clindamycin, penicillins)
Term
What is the new "hypervirulent" C. diff strain?
Definition
NAP 1/027
Term
What is the first line treatment for C. diff that the new hypervirulent strain is resistant to?
Definition
metronidazole (Flagyl)
Term
What is the treatment for the new hypervirulent strain of C. diff?
Definition
vancomycin
Term
What bacterial infection can you get from contaminated fried rice or dried beans?
Definition
Bacillus cereus
Term
With Bacillus cereus food poisoning, the emetic toxin is found in _______.
Definition
fried rice
Term
With Bacillus cereus food poisoning, the diarrheal toxin is found in _________.
Definition
dried beans
Term
Bacillus cereus spores are not killed by _________.
Definition
boiling
Term
common food poisonings
Definition
Staphylococcus aureus
Bacillus cereus
Clostridium botulism
Term
What bacteria is responsible for food poisoning after eating potato or egg salads, mayonnaise, and cream pastries?
Definition
Staphylococcus aureus
Term
incubation period for S. aureus food poisoning
Definition
1-6 hours
Term
S. aureus food poisoning comes from a ___________ toxin in the food.
Definition
preformed
Term
What bacteria is responsible for food poisoning from ingestion of heavily contaminated meats, poultry, or legumes?
Definition
Clostridium perfringens
Term
incubation period for Clostridium perfringens
Definition
8-14 hours
Term
What bacteria is responsible for infantile botulism from honey?
Definition
Clostridium botulinum
Term
Shigella infection is characterized by degeneration of the ___________ and inflammation of the ________ _________.
Definition
epithelium; lamina propria
Term
Shigella infection results in ___________ and _____________ of the colon mucosa.
Definition
desquamation; ulceration
Term
What causes a watery non-inflammatory diarrhea with dehydration due to large fluid loss (speckled with flakes of mucus and epithelial cells) and is an oxidase positive, gram negative, curved bacillus requiring special media?
Definition
Vibrio cholerae
Term
What causes a diarrhea after eating raw shellfish due to oxidase positive, gram negative, curved bacilli that require special media?
Definition
Vibrio parahaemolyticus
Term
What bacteria do you get from eating uncooked coastal marine saltwater shellfish (raw oysters, sushi)?
Definition
Vibrio parapaemolyticus
Term
What is the leading cause of diarrhea in Japan?
Definition
Vibrio parahaemolyticus
Term
What bacteria causes wound infections, gastroenteritis, or a syndrome known as "primary septicemia?"
Definition
Vibrio vulnificus
Term
transmission of V. vulnificus
Definition
eating contaminated seafood
open wound exposed to Gulf Coast seawater
Term
What condition can cause a V. vulnificus infection to be even more serious?
Definition
immunocompromised--especially liver disease (causes primary septicemia)
Term
severest form of salmonella infections
Definition
Salmonella typhi (typhoid fever)
Term
curved bacilli
Definition
vibrio
campylobacter
Term
facultative anaerobes
Definition
salmonella
Term
obligate anaerobes
Definition
bacteroides
Term
fastidious enterics
Definition
campylobacter
vibrio
yersinia
Term
microaerophilic enterics
Definition
campylobacter
H. pylori
Term
lactose fermenters
Definition
vibrio
E. coli
Term
non-lactose fermenters
Definition
shigella
salmonella
proteus (UTI)
yersinia
campylobacter
Term
motile enterics
Definition
salmonella
Term
non-motile enterics
Definition
shigella
Term
oxidase positive enterics
Definition
vibrio
campylobacter
Term
oxidase negative enterics
Definition
shigella
E. coli
salmonella
Term
H2S producers
Definition
salmonella
Term
catalase positive enterics
Definition
E. coli
Term
catalase negative enterics
Definition
salmonella
Term
invasive enterics
Definition
shigella
salmonella
campylobacter
E. coli (EIEC, EHEC)
yersinia
clostridium (gram +)
Term
toxigenic enterics
Definition
vibrio
E. coli (ETEC)
Term
gram + enterics
Definition
Clostridium difficile
Bacillus cereus
Staphylococcus aureus
Clostridium botulinum (neurotoxin)
Clostridium perfringens
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