Microbiology Chapter 19

Digestive System Infections

List the organs that comprise the upper GI tract.

mouth, pharynx, esophagus, and stomach

List the organs that comprise the lower GI tract.

small intestines, large intestines, rectum, and anus

List the accessory organs of the digestive system.

salivary glands, liver, gallbladder, and pancreas

The GI tract is associated with lymphatic tissues such as tonsils, appendix, and Peyer’s patches. Why is this important?

it is a major entry portal of pathogens

Which 2 organic macromolecules begin in the digestive process in the mouth?

lipids and carbohydrates

Like 3 chemical barriers that are utilized in the digestive system.

lysozyme, acidic gastric juices, salts in bile

Our normal gut microbiota uses several strategies to decrease the chances of an incoming pathogen establishing itself in the gut. List 3 strategies.

occupying space, competing for nutrients, producing antimicrobial substances

Define diarrhea.

frequent passing of loose or watery stool

Define enteritis.

inflammation of the intestines

Define gastritis.

inflammation of the stomach

Define gastroenteritis. 

inflammation of the stomach and intestines

Define dysentery.

diarrhea accompanied by pain, blood, and/or mucus

Define dehydration.

excessive loss of body fluid, may develop due to severe diarrhea and/or vomiting

Define hypovolemic shock.

low blood volume due to loss of blood or severe dehydration, can lead to organ failure

Are EMB and MAC media general nutritional media, selective, differential, or selective and differential media?

selective and differential

What does EMB select for? What does it differential between? 

gram-neg; fermentation of lactose

What does MAC select for? What does MAC differentiate between?

gram-neg; fermentation of lactose

Upper and lower GI endoscopy can determine the presence of tissue damage and inflammation in the GI tract. What can’t this procedure determine?

the specific microbial agent responsible for the pathology 

What type of microbe causes mumps? Which salivary gland is mainly infected?

RNA virus; parotid gland

Which 2 viruses are the most common cause of gastroenteritis (stomach flu)? What is the main route of entry for these viruses? 

rotavirus and norovirus; fecal-oral transmission

Define hepatitis. 

inflammation of the liver

T or F, correct if F: The genetically related Hepatitis A, B, and C viruses are the main cause of infectious hepatitis. 

FALSE, they are not genetically related

Describe the appearance of a person with jaundice.

yellowing of the skin and whites of the eyes

Define viremia.

presence of virions in the blood

What are the most common ways that HepB is transmitted?

direct contact with bodily fluids or open sores from an infected individual (sex, sharing needles/razors/toothbrushes)

Which 2 prophylaxes are administered to a newly delivered baby if the mother is infected with HepB?

HBIG (HepB immune globulin) or vaccines

Define cirrhosis. 

scarring of the liver

Why is HepC referred to as the silent killer?

it typically remains asymptomatic for many years until significant damage is done

Which hepatitis virus causes the most common chronic bloodborne infection in the US?

HepC

Define dental caries. 

cavities, bacteria present in the mouth create acids that eat away at the enamel

Define gingivitis.

infection of the gums

Define periodontitis.

inflammation and eventual erosion of the bone that surrounds the tooth

What is dental plaque?

complex biofilm created by attachment of bacteria to the tooth enamel

What is the main bacterial species that causes dental caries?

Streptococcus mutans

What is the main bacterial species that causes gastritis and stomach ulcers? 

Helicobacter pylori

What pathogen is the most common causative agent of foodborne illness?

norovirus

What is the difference between a foodborne infection and food poisoning?

food poisoning has no infection

Infection with which bacteria has been linked to gastric cancer?

Helicobacter pylori

Define entertoxin.

bacterial exotoxins that target intestines, inflammation

Define emetic.

toxins that trigger vomiting

What is botulism and what pathogen causes it?

food poisoning from spore-forming Clostridium botulinum

What toxin-producing fungus can cause food poisoning? What is the name of the toxin? 

Aspergillus flavus; alfatoxin

What bacterial species is the leading cause of bacterial foodborne illness? How does one mainly contract the bacteria?

Campylobacter jejuni; eating undercooked poultry or cross-contamination

Define septic shock.

dangerously advanced stage of sepsis where the bodies organs start to shut down (20-30% mortality rate)

Define bacteremia.

bacteria found in the blood

Define sepsis.

a body-wide immune response to persistent or large numbers of microbes in the blood

What toxin is made by no other Shigella sp. except Shigella dysenteriae, and can cause hemolytic uremic syndrome? 

Shiga toxin

Define edema.

generalized swelling, often in the extremities, in response to fluid accumulation in tissues

Define purpura.

a rash of purple spots/bruising caused by RBC lysis and/or capillary destruction rather than by external physical trauma

Define hematuria.

blood in the urine

The Escherichia coli pathotype called O157:H7 it is the most common dysentery-associated serovar in the US. What acquired toxin makes this pathotype cause such severe symptoms? 

Shiga toxin

Name 2 serovars of Salmonella enterica that causes most causes of Salmonella-associated diarrhea and dysentery. 

Enteritidis and Typhimurium

What bacterial genus, species, and serovar causes typhoid fever?

Salmonella enterica, Typhi

What bacterial species is the etiological agent of cholera?

Vibrio cholerae

What bacterial species is on the top of the CDCs list of emerging public healthcare threats and is among the most common causes of HAIs?

C. Diff

What bacterial species can cause pseudomembranous colitis? 

C. Diff

Which protozoan is the most common intestinal parasite in the US, and it can cause “traveler’s diarrhea”?

Giardia lamblia, giardiasis

What protozoan causes amebiasis (AKA amebic dysentery)?

Entamoeba histolytica

Oocysts from which apicomplexan parasite causes crytosporidiosis?

cryptosporidium

Which species of tapeworm is known as the dwarf tapeworm and is the single most common cause of human tapeworm infection?

Hymenolepis nana

What helminth mainly infects cattle?

Taenia species, T. saginata

Ingestion of which helminth’s eggs causes cysticercosis?

T. solium

What helminth is commonly known as fish tapeworm?

Diphyllobothrium latum

Which roundworm causes pinworm infection?

white, Enterobius vermicularis

Which roundworm causes hookworm infection? 

soil-transmitted, Necator americanus

What helminth causes ascariasis?

Ascaris lumbricoides

What roundworm causes trichinellosis?

Trichinella, T. spiralis

Schistosoma haematobium, S. japonicum, and S. mansoni cause which illness?

Schistosomiasis