Bacterial and Fungal Infections of the Lower GI Tract – Part 2

What are the primary functions of the lower gastrointestinal tract?

Digestion, absorption, defecation, and protection.

What is the role of bile in digestion?

Bile digests fats.

Where are nutrients, water, and electrolytes primarily absorbed?

In the small intestine.

What protects the gastrointestinal tract from pathogens?

Mucus, GALT (immune tissue), and the microbiome.

What percentage of bacteria in the gut microbiome are anaerobic?

99%.

What do bacteria in the gut microbiome ferment to produce vitamins?

Fibre.

Where do microbial numbers peak in the GI tract?

In the colon.

What are the specific areas where bacteria exist in the gut?

Lumen, mucosal layers, and crypts.

How do microbiome composition changes occur throughout life?

Begins before birth and changes with age and environment.

Which types of bacteria dominate early in life?

Firmicutes.

What are some roles of commensal bacteria in the gut?

Competing with pathogens, digesting fibre, and producing vitamins.

What are antimicrobial peptides (AMPs)?

Substances secreted by gut cells to kill pathogens.

Which cells in the gut produce lysozyme and phospholipase?

Paneth cells.

What is GALT in the context of gut immunity?

Gut-associated lymphoid tissue, the largest immune organ.

What is Campylobacter jejuni and how is it transmitted?

A Gram-negative bacterium mainly transmitted via undercooked poultry.

What serious condition can be triggered by Campylobacter jejuni infection?

Autoimmune paralysis, such as Guillain-Barré syndrome.

How do typhoidal Salmonella differ from non-typhoidal Salmonella?

Typhoidal causes typhoid fever and is spread human-to-human; non-typhoidal causes foodborne illness.

What is the Type III secretion system used by Salmonella?

A mechanism to inject toxins into host cells.

What is the typical treatment for a Salmonella infection?

Usually self-limiting; severe cases may be treated with ciprofloxacin or azithromycin.

What is Clostridioides difficile also known as?

C. diff.

What triggers the overgrowth of C. difficile in the gut?

Antibiotics that disrupt normal gut flora.

What are the key toxins produced by C. difficile?

Toxins A and B.

What is the first step in treating C. difficile infection?

Stop the original antibiotics.

What is a highly effective treatment for recurrent C. difficile cases?

Faecal Microbiota Transplant (FMT).

Which fungal infection can cause sepsis in the GI tract?

Candida albicans.

What is Listeria monocytogenes known for?

Being a Gram-positive bacterium that can grow at refrigerator temperatures.

What are the key takeaways about the gut microbiome and pathogens?

The gut microbiome is vital for digestion and immunity while certain pathogens can lead to severe GI infections.

What is essential for preventing GI infections from pathogens?

Good hygiene, proper cooking, and prudent antibiotic use.

What is the main mode of transmission for Listeria monocytogenes?

Found in soil, water, and animals.

What role does the gut microbiome play beyond digestion?

It also plays a critical role in immune function and protection.