Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

13. Gastrointestinal > 9. Microbiology of the Gastrointestinal Tract > Flashcards

9. Microbiology of the Gastrointestinal Tract Flashcards

1
Q

What are the beneficial roles of normal flora in the GI tract?

A

Synthesise and excrete vitamins (K, B12, thiamine), prevent colonisation by pathogens (space, bacteriosides), kill non-indigenous bacteria (bacteriosides), stimulate development of GALT, and stimulate production of natural antibodies.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are obligate aerobes?

A

Must have oxygen to survive.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an example of a gut flora obligate aerobe?

A

Pseudomonas or mycobacterium TB.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are obligate anaerobes?

A

They die in the presence of oxygen.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example of a gut flora obligate anaerobe?

A

Bacteroides fragilis, clostridial organisms.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do clostridium spp survive in aerobic environments?

A

They form a protective spore.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are facultative anaerobes?

A

They prefer oxygen but can live without it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is an example of a gut flora facultative anaerobe?

A

Gram negative enteric like E. coli, or gram positive skin-dwellers like staphylococcus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the anaerobic zones of the GI tract?

A

Parts of mouth - tongue deep in taste buds, biofilm between teeth, gingival crevice areas. Small bowel. Colon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the gram positive aerobic cocci in the GI tract?

A

Staphylococci, strpetococci, enterococci.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the gram negative aerobic cocci in the GI tract?

A

Neisseria meningitides, and neisseria gonorrhoeae.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the gram negative aerobic bacilli in the GI tract?

A

Corynebacterium (diphtheria), bacillus (anthrax), mycobacterium TB (acid fast).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the gram negative anaeobic bacilli in the GI tract?

A

Clostridia (tetani, perfringens, difficile).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the gram negative aerobic enteric bacilli in the GI tract?

A

E.coli, pseudomonas, proteus, klebsiella, salmonella, shigella, vibria cholerae, campylobacter, helicobacter pylori.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the gram negative aerobic non-enteric bacilli in the GI tract?

A

Haemophilus influenzae, bordetella pertussis, brucella.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the gram negative anaerobic bacilli in the GI tract?

A

Bacteroid fragilis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the common anaerobic bacteria of the mouth?

A

Streptcocci, staphylococci, candida, lactobacillus, enterococcus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does streptococcus mutans cause in the mouth?

A

Denta caries/ gingivitis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does staphylococcus aureues cause in the mouth?

A

Parotitis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What can candida albicans cause in the mouth?

A

Oral thrush.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is noma/ cancrum oris?

A

Anaerobic bacteria causing tissue destruction in the mouth of malnourshied, dehydrated, immunocompromised, or systemically unwell patients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the common bacteria of the nose?

A

Staphylococcus and streptococcus.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the three screening sites for MRSA swabs?

A

Nose, throat, and perineum.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the throat bacteria and fungi?

A

Streptococcus viridans, streptococcus pyogenes, streptococcus pneumoniae, staphylococci, neisseria meningitidis, haemophilus influenzae, lactobacilli, corynebacterium diptheriae, candida albicans.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How does strep. viridans enter the blood stream?

A

It is in 100% of people in their throats, when teeth are brushed, or in dental procedures, or general anaesthesia, the non-pathogenic throat commensal can enter the blood.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What can strep. pyogenes cause?

A

Tonsillitis, only 30% of cases, other 70% is viral.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is strep. pneumoniae a cause of?

A

Community acquired pneumonia, accounts for 30% of cases.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is haemophilus influenzae a cause of?

A

Community acquired pneumonia, accounts for 13% of cases.

29
Q

What is the purpose of lactobacilli in the vagina?

A

Makes vagina acidic so candida albicans can’t grow, so prevents thrush.

30
Q

What are the viral causes of tonsillitis?

A

Adenovirus, rhinovirus, epstein-barr virus (EBV).

31
Q

What is the stomach bacteria that infects at least half the world?

A

Helicobacter pyloris.

32
Q

What percentage of those infected with H. pylori develop gastric/ duodenal ulcers?

A

10-20%.

33
Q

What percentage of duodenal and gastric ulcers is H. pylori associated with?

A

90% of duodenal ulcers, 70% of gastric ulcers.

34
Q

What are the common anaerobe species in the colon?

A

Bacteroides and clostridial species.

35
Q

Which bacteria are always present in the colon?

A

Bacteroides fragillis, bacteroides oralis, bacteroides melaninogenicus, E. coli, entercoccus faecalis.

36
Q

What are the top two causes of UTIs?

A

E. coli, and enterococcus faecalis.

37
Q

What are the gram negative enteric bacilli that are sometimes present in the colon?

A

Pseudomonas, proteus, klebsiella, salmonella, shigella, vibrio cholera, campylobacter.

38
Q

What is a major difference between the colon and small bowel in terms of bacteria?

A

It is normal for the colon to have lots of bacteria, but abnormal for the small bowel to.

39
Q

Why is gut surgery viewed as dirty surgery?

A

There are so many bacteria so a high risk of wound infection.

40
Q

How is the risk of surgical wound infection reduced with gut surgery?

A

Antibiotics are given prophylactically.

41
Q

What must the prophylactic antibiotics given for gut surgery be able to cover?

A

Anaerobes, gram negative bacilli and gram positive bacilli.

42
Q

What are the prophylactic antibiotics normally given for gut surgery?

A

Metronidazole for anaerobes, and broad spectrum antibiotics like gentamicin or cephalosporin.

43
Q

Why has faecal peritonitis got a high mortality rate?

A

Due to the huge numbers of bacteria that are now floating free in the peritoneum.

44
Q

What is a perianal abscess?

A

Glands in the anal canal that produce mucus for lubrication to aid with passing faeces are infected and abscess around the anus.

45
Q

What is a normal vaginal gram positive bacilli bacteria?

A

Lactobacillus.

46
Q

How does lactobacillus create an acidic environment for the vagina?

A

It converts glycogen into lactic acid.

47
Q

Which of the following could be present in perineal skin and why? Bacteroides, E. coli, enterococcus faecalis, lactobacillus.

A

Bacteroides won’t as they can’t survive O2. The others all could be present as they can survive in the presence of O2.

48
Q

What is the group of bacteria that cause UTIs?

A

Gram negative enteric bacilli.

49
Q

What does clostridia tetani cause?

A

Tetanus.

50
Q

How many neonates die from tetanus each year?

A

60000.

51
Q

What does clostridia difficile cause?

A

Pseudomembranous colitis - severe inflammation of the colon.

52
Q

When does clostridia difficile often arise?

A

After antibiotic use.

53
Q

What does clostridia perfringens cause?

A

Gas/wet gangrene.

54
Q

How does clostridia perfringens cause gas/wet gangrene?

A

Anaerobic digestion of glucose leads to ethanol and CO2.

55
Q

What does norovirus cause?

A

Vomiting and diarrhoea?

56
Q

What does gastroenteritis often follow?

A

Consumption of food or drink contaminated with organisms or toxins - food poisoning.

57
Q

What is the presentation of gastroenteritis?

A

Rapid onset or up to 48 hours of ingestion of vomiting and diarrhoea.

58
Q

What are the common causative organisms and toxins of gastroenteritis?

A

Salmonella, campylobacter, and listeria bacteria. Or toxins from staphylococcus and clostridium.

59
Q

What causes cholera?

A

Vibrio cholerae.

60
Q

What are the effects of vibrio cholerae on the ileum?

A

Lead to mass movement of water and salt into the lumen by active secretion leading to serious diarrhoea - rice water appearance from intestinal secretions plus mucus.

61
Q

Why can cholera be life threatengin?

A

Rapid, severe dehydration following the severe diarrhoea can be life threatening.

62
Q

How is cholera managed?

A

Replace lost water and electrolytes with appropriate replacement fluids.

63
Q

What are some parasite causes of gastroenteritis?

A

Giardia and cryptosporidium protozoans.

64
Q

What can helminth infections of the intestines lead to?

A

Malabsorption as well as other things.

65
Q

What is bacteraemia?

A

Bacteria are rapidly cleared from the bloodstream by liver and spleen macrophages so no symptoms.

66
Q

What is septicaemia?

A

Bacteria are not cleared and multiply in the blood stream. Sepsis symptoms develop.

67
Q

What is ETEC?

A

Enterotoxinogenic E. coli.

68
Q

What does ETEC cause?

A

Travellers’ diarrhoea in developing countries.

13. Gastrointestinal (17 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions