Bowel Microflora y1s2 keely

Question 1

How many cells does the human body contain?

Answer 1

10 trillion human cells (10^13)

Question 2

How many bacteria is in the human gut contain?

Answer 2

> 100 trillion (10^14) in the gut alone!

Question 3

Are all bacteria in the gut identified?

Answer 3

Many bacteria yet to be identified, cannot be grown outside the body.

Question 4

What is our health dependent on in terms of bacteria?

Answer 4

Our health dependent on the delicate balance between bacterial and
human cells.

Question 5

How can bacteria cause disease?

Answer 5

Large inoculum, Antimicrobial drugs, Host factors (reduced peristalsis + immune suppression), physical destruction (irradiation, chemicals, burns)

Question 6

How can bacteria protect us from disease?

Answer 6

Layer formation by normal flora, Waste product formation by normal flora, immune stimulation

Question 7

What do probiotics do?

Answer 7

Development of mucosal layer
Synthesis of vitamins
Metabolism of bile acids
Production of short chain fatty acids
Reduction of pH in large bowel
Immune system activation

Question 8

Key concepts on host-bacterial relations?

Answer 8

The human body is under constant attack from microbial infection.
 Some microbes within the normal human microflora can become pathogenic if the state of the host changes – opportunistic pathogens.
 Other microbes are present in the environment and can infect a host if the host defences are penetrated.
 Exposure to microbes which can cause disease in normal hosts, i.e. those with normal defence mechanisms - Primary pathogens

Question 9

Commensal (normal) bacteria causes disease if…

Answer 9

 Local or systemic host defenses are compromised
(eg Acute pancreatitis)
 Spreads to site outside the GI tract, not normally present (eg. UTI, SIRS)

Question 10

Environmental flora may cause disease if…

Answer 10

 Primary pathogen (eg. Salmonella sp.)

 Ingested/present in sufficient numbers

Question 11

Commensal AND environmental flora can both cause disease because…

Answer 11

 Pathogen has attributes making it more virulent &/or evades host defences
 Aided if local or systemic host defence mechanisms are compromised
 Multiply
 Release toxins or induce inflammatory damage

Question 12

What are symptoms of GIT diseases?

Answer 12

nausea, vomiting, diarrhea, pain

Question 13

What can GI diseases lead to?

Answer 13

Gastroenteritis: Inflammation of stomach & intestines
 Diarrhea: abnormal watery faecal discharge
 Dysentry: inflammation of large intestine
 Enterocolitis: inflammation of surface of small & large intestine

Question 14

What are common causes of GI disease?

Answer 14

Common sources:
 Consumption of contaminated food/water source (eg. 2011 European E. coli)
 Food poisoning/infection (undercooked food - salmonella)
 Faecal/oral route (wash your hands!!!)
 Causative agents:
 Bacteria, viruses, parasites