MICROBIOL: Chapter 22

which of the following causes pseudomembranous colitis

Clostridium difficile

the leading cause of paralysis in the U.S since the eradication of polio is ___-___ ___.

Guillain-Barre syndrome

which of the following tests aid in the diagnosis of giardiasis

PCR. ELISA.

plusenet is a database of information on common food-borne pathogens obtained from performing which technique

PFGE

hepatitis C virus is a ___ virus

RNA

___ cells are curved and rod shaped

Vibrio

which of the following is not a method of diagnosis of amoebiasis

acid fast stain

EAEC is distinguished by ability to adhere to human cells in ___ rather than as single cells

aggregates

the ___ pH and digestive juices of the small intestine stimulate excystment of entamoeba histolytica

alkaline

although cyclospora is a protozoan, the best treatment for an infection is not anti-protozoan drugs, but rather

antibiotics

hepatitis A infection can be diagnosed by direct tests that detect Hepatitis A ___ or virus directly in stool samples

antigen

the diarrheal form of ___ ___ exotoxin food poisoning is associated with cooked meats or vegetables held at warm temperatures for long period of time

bacillus; cereus

the most common mode of transmission of STEC is ingestion of contaminated and undercooked ___.

beef

Vibrio cholera travels through the digestive tract and penetrates the mucous barrier

between the duodenum and the jejunum

the hepatitis C virus is acquired in similar ways to hepatitis B virus, but it is more commonly transmitted through ___ contact

blood

which of the following is not an effect of clostridium perfringens exotoxin

bloody stools

which of the following can be used to control giardia

boiling, ozone

___ and ___ are at risk of acquiring giardiasis, especially in remote mountain areas

campers; hikers

EAEC is especially associated with chronic diarrhea in ___

children

the people most vulnerable to EAEC are those who are malnourished ___ in developing countries

children

the virulence of vibrio cholerae is due to

cholera toxin

diarrhea which lasts longer than 14 days is called ___ diarrhea

chronic

___ is an intestinal disease caused by a protozoan of the apicomplexan type

cryptosporidiosis

which of the following statements are correct regarding the transmission of entamoeba

cyst formation occurs during the encystment phase of the life cycle. chronic carriers continuously shed the cyst form of entamoeba

giardia lamblia ___ are highly resistant structures and can survive for two months in the environment

cysts

the delta agent, or hepatitis D virus is an

defective RNA virus that coinfects with hepatitis B

which of the following is a characteristic of rotavirus

double -stranded RNA. reovirus.

the pathogenesis of giardia begins when cysts enter the ___, germinate, and travel to the ___ where they feed and multiply

duodenum, jejunum

___ is the proper term for a diarrheal illness in which stools contains blood and/or mucus

dysentery

the best prevention of STEC in humans is

eat only well cooked hamburger

rotavirus can be identified using a ___ microscope to view a stool sample

electron

something that induces vomiting is called a ___

emetic

entamoeba is harbored by chronic carriers whose intestines favor the ___ stage of the organism's life cycle

encystment

a ___ is a bacterial toxin that specifically targets intestinal mucous membrane cells

enterotoxin

the virulence of vibrios is due to the production of a ___ which disrupts the normal physiology of intestinal cells

enterotoxin

what type of toxin specifically targets intestinal mucous membrane cells

enterotoxin

the staphylococcus aureus exotoxin attacks gastrointestinal ___ cells and stimulates ___ to cause cramping, vomiting, and diarrhea

epithelium; nerves

cyclospora cayetanensis is a fungus

false

entamoeba histolytica amoebas are often packed with food vacuoles containing chromatoidal bodies

false

the best prevention of shigellosis is the use of a vaccine

false

there is no treatment for giardia beyond watchful waiting

false

humans accidentally ingest cryptosporidium oocytes with water and food that has been contaminated with ___ from infected animals

feces

in a fecal transplant, ___ from a healthy person is transplanted to the patient

feces

which of the following groups is not considered to be at high risk for hepatitis B infection

food handlers

cyclospora transmission usually occurs when one ingests fecal contaminated ___ and ___

food; water

the emetic form of B. cereus exotoxin disease is frequently associated with ___ ___

fried rice

___ lamblia is a pathogenic flagellated protozoan that is associated with chronic diarrhea

giardia

STEC infection results in effacement of enterocytes, ___. the net effect is a gut lesion in the large intestine that produces bloody diarrhea

gut epithelial cells

which of the following is true of the shiga toxin

heat-labile. it causes serious damage to the large intestine.

escherichia coli infections may lead to ___ ___ syndrome, a severe anemia leading to kidney damage or failure

hemolytic uremic

___ is an viral inflammatory disease of the liver that is characterized by necrosis of hepatocytes and a disruption in liver structure

hepatitis

clostridium difficile is found as normal biota of the ___.

intestine

which of the following water purification methods are used to control E. histolytica cysts

iodine. boiling.

which of the following are non-microbial forms of chronic diarrhea

irritable bowel syndrome. ulcerative colitis. crohn's disease

which of the following statements accurately reflects characteristics of E. coli O157:H7

it is commonly referred to as STEC

the trophozoite of entamoeba histolytica contains a single nucleus with a large nucleolus called an ___

karyosome

the trophozoite of entamoeba histolytica lacks most of the organelles found in other eukaryotes and contains a single nucleus with a large nucleolus that is called a ___

karyosome

shigella invades cells of the

large intestine

binding of the cholera toxin to specific intestinal cell receptors triggers

loss of water and electrolytes

because a liver infected with hepatitis B virus continuously seeds the blood with virus, the minimal dosage to transmit infection is

low

campylobacteria species are gram-___, ___ or spiral shaped bacteria

negative; curved

which of the following are characteristics of the hepatitis A virus

nonenveloped. single-stranded RNA.

the most common cause of viral gastroenteritis is

norovirus

the usual route of shigellosis is the ___ route

oral

the endospores of clostridium ___ that survive cooking can germinate on unrefrigerated, cooling foods such as meat, fish, and vegetables

perfringens

bacillus cereus is a spore forming, gram-___ bacterium that is naturally present in soil

positive

farm products other that meat that may become contaminated by cattle feces include

products that are consumed raw. unpasteurized juices.

vibrio cholerae uses ___ ___ as a means to regulate the expression of its virulence factors

quorum sensing

vibriosis is caused by consuming contaminated

raw oysters

possible reservoir for giardia include all of the following except

rodents

effective cholera prevention is dependent on proper ___ treatment and ___ purification

sewage; water

hepatitis B can be transmitted by

shared razors/toothbrushes. body fluids. tattooing and piercing.

much of the virulence of STEC is due to the production of

shiga toxin

which of the following organisms produce exotoxins that can cause food poisoning

staphylococcus aureus. clostridium perfringens. bacillus cereus.

vibrio cholera can be identified in a ___ sample

stool

vibrio cholera may be readily cultured in the laboratory from patient ___ samples

stool

PFGE is a technique that examines small variations in ___ to identify microbes to the level of a strain

the chromosome

oral-anal sexual contact transfers pathogens to ___ partners

the oral

the mode of transmission of EAEC is contaminated food and water

true

entamoeba histolytica actively penetrates deeper layers of the intestinal mucosa, leaving ___

ulcerations

which of the following is not associated with the spread of shigellosis

unprotected sex

infection with non-cholera vibrio species is called ___

vibriosis

jaundice is characterized by which of the following

yellow-tinged skin and eyes. bilirubin in blood.

C. difficile produces ___ enterotoxins that target the wall of the intestine

2

hepatitis ___ is usually spread through the fecal-oral route and can be prevented by vaccination

A

tattooing and ear or body piercing increases the risk of acquiring hpatitis

B