Normal Microbiota (10)

Question 1

Normal flora

Answer 1

Organisms found in a given location in a state of health

Question 2

Colonisation

Answer 2

Establishment at a site in the body

Question 3

Symbiosis

Answer 3

Two/more organisms co-exist in close physical association

Question 4

Mutualism

Answer 4

Both organisms benefit from symbiosis

Question 5

Neutralism

Answer 5

Neither organisms derives benefit or harm

Question 6

Commensalism

Answer 6

One organism benefits, the other derives neither benefit nor harm

Question 7

Parasitism

Answer 7

One organism/parasite benefits at the expense of the other/host

Question 8

Non-sterile sites

Answer 8

Have normal flora (skin, vagina, conductive, nasopharynx, GI tract)

Question 9

Sterile sites

Answer 9

No normal flora

Question 10

Sterility maintained by barriers

Answer 10

Upper genital tract - cervix

Urinary tract - urethra

Middle ear - eustachian tube

Question 11

Sterility maintained by physical separation

Answer 11

Pleural cavity, peritoneal cavity, spinal cord and meninges

Question 12

Sterility maintained by surface cleaning

Answer 12

Lower respiratory tract - ciliated epithelium (cough/sneeze/swallow)

Question 13

Tissue tropism

Answer 13

Propensity for a particular organism to grow in a particular habitat

Question 14

Skin

Answer 14

Variable temperature, dry, subject to abrasion, aerobic environment, nutrient-poor, skin surface components

Question 15

Gingival crevice

Answer 15

Constant temp, moist, toothbrush-physical challenge, anaerobic, bathed in nutrient, mucosal surface components

Question 16

Skin flora

Answer 16

Coagulase-negative staphylococci (Staphylococcus epidermis)

Staph aureus/Propionibacterium acnes

Question 17

Mouth flora

Answer 17

Viridans/oral streptococci/anaerobes

Question 18

Nasopharyngeal flora

Answer 18

• Nostrils, 20%, S.aureus

- Pharynx

Question 19

Vagina pre-puberty

Answer 19

Skin flora/lower GI flora (E.coli)

Question 20

Vagina post-puberty

Answer 20

Glycogen produced due to oestrogen, lactobacillus acidophilus (ferment glycogen maintain pH 3)/skin flora/few C.albicans

Question 21

GI flora

Answer 21

Low pH inhibits growth, aerobic - acid-tolerant Lactobacilli/H.pylori

Question 22

Large intestine flora

Answer 22

> 400 species, 99% anaerobic (bactericides, clostridium, bifidbacteria), aerobic (enteric gram negative bacilli)

Question 23

Benefits of normal flora

Answer 23

• Synthesis and excretion of vitamins (K and B12 enteric)
• Colonisation resistance (environmental manipulation/antibacterial agents)
• Cross-reactive antibodies

Question 24

What is human microbiota composition measured by?

Answer 24

16S RNA

Question 25

Micro biome and human health

Answer 25

IBD, diabetes, hypertension, obesity, cancer, infection - c.diff

Question 26

C.diff

Answer 26

Hospital acquired infection, >60 years, perturbation of normal colonic microflora allows C.difficile overgrowth > toxin production > diarrhoea (Pseudomembranous colitis)

Question 27

What is main risk factor for c.diff?

Answer 27

antibiotic treatment

Question 28

Faecal transplant used to treat?

Answer 28

C.diff (chronic diarrhoea and food poisoning)

Question 29

Suggested faecal transplant has positive effect for

Answer 29

MS, CFS, idiopathic thrombotic purport, ulcerative colitis, IBS, diabetes

Question 30

Pathology of normal flora

Answer 30

Overgrowth (thrush), Translocation (conjunctivitis/inoculation into a normally sterile site), cross-infection (MRSA)

Question 31

Clinical conditions caused by normal flora

Answer 31

Abscesses, pneumonia, endocarditis, gastroenteritis, peritonitis, urogenital infections, dental caries, periodontal disease, pharyngitis