Medical Microbiology Digestive Diseases

11/6/2025

GI infections are…

common

The crown of the tooth is covered with

enamel

Enamel is the hardest material in the body, True or False?

True

Microbes such as bacteria and archaea are abundant in the mouth and coat all of the surfaces of the 

oral cavity 

Saliva contains enzymes such as BLANK which can damamge microbial cells.

Lysozymes

Lysozymes can what?

Can cleave the glycosidic linkage between NAG and NAM in peptidoglycan. 

True or false, our mouth does not have a rich microbiota. 

False

Goblet cells line the GI tract and help form a protective layer by producing

mucus

Periodontal diseases include

gingivitis 

Inflammation and bleeding of the gums is

gingivitis

What occurs with gingivitis?

Bacteria colonize the space between the teeth and gums, or gingival space. The environment becomes anaerobic as the space becomes blocked.

Chronic gingivitis can turn into

Periodontitis

What is it when the gums recede and exposes the parts of the tooth below the crown?

Periodontitis

Why is periodontitis bad for your teeth?

The newly exposed area is relatively unprotected, so bacteria can grow on it and spread underneath the enamel of the crown and cause cavities.
- Bacteria in the gingival space can also erode the cementum, which helps to hold the teeth in place.
- If not treated, erosion of cementum can lead to the movement or loss of teeth.
- The bones of the jaw can even erode if the infection spreads. This condition can be associated with bleeding and halitosis (bad breath).

What is Trench mouth?

Also known as acute necrotizing ulcerative gingivitis, or Vincent’s disease, comes after Periodontitis progresses.

The yeast Candida is part of the normal human microbiota, but overgrowths, especially of Candida albicans, can lead to infections in several parts of the body. What is this called?

Thrush 

Who most commonly has thrush?

Infants

What is oral thrush characterized by?

the appearance of white patches and pseudomembranes in the mouth and can be associated with bleeding

The viral disease mumps is an infection of the parotid glands, the largest of the three pairs of salivary glands. What causes it?

mumps virus (MuV), a paramyxovirus with an envelope that has hemagglutinin and neuraminidase spikes. 

• A fusion protein located on the surface of the envelope helps to fuse the viral envelope to the host cell plasma membrane.

Mumps virus is transmitted through respiratory droplets or through contact with contaminated saliva, making it quite contagious so that it can lead easily to epidemics. 

• It causes fever, muscle pain, headache, pain with chewing, loss of appetite, fatigue, and weakness. 

True or false: there is no treatment for mumps, but there is a vaccine.

True, (MMR vaccine)

Wat are Rotaviruses?

Double-stranded RNA in the family of Reoviridae. 

Rotaviruses are responsible for what?

Common diarrheal illness, but there are now more protections with vaccines.

What are symptoms of Rotavirus infections?

Fever, vomiting, diarrhea.

Where is rotavirus typically found?

In the small intestines, on epithelial cells of the villi. It can survive in the stomach, but is usually found in the small intestine.