MOD 10 - Normal Flora

Question 1

How much microbe there is in the body?

Answer 1

10x10 (14)

Question 2

definition of normal flora

Answer 2

organisms found in a given location in a state of health

Question 3

definition of colonisation

Answer 3

establishment at a site in the body

Question 4

definition of symbiosis

Answer 4

2 or more organism co-exist in close physical association

Question 5

definition of mutualism

Answer 5

both organisms benefit from symbiosis

Question 6

definition of neutralism

Answer 6

neither organism derives benefits or ham

Question 7

definition of commensalism

Answer 7

one organism benefits, the other derives neither benefit nor harm

Question 8

definition of parasitism

Answer 8

parasite benefits at the expense of the host

Question 9

definition of non-sterile sites

Answer 9

have normal flora

Question 10

definition of sterile sites

Answer 10

no normal flora

Question 11

how does a non-sterile site become non-sterile

Answer 11

exposed to the environment directly or indirectly & no mechanisms in place to maintain sterility

Question 12

where are some of the non sterile sites

Answer 12

conjunctiva, nasopharynx, GI tract, skin, vagina, lower respiratory tract

Question 13

how is lower respiratory tract maintain sterility

Answer 13

by surface cleaning (ciliated epithelium and then coughing etc)

Question 14

definition of tissue tropism

Answer 14

propensity for a particular organism to grow in particular habitat

Question 15

where does most bacteria colonise in the skin

Answer 15

sweat glands - moist and nutrient

Question 16

what are some examples of normal skin flora?

Answer 16

coagulase -ve staphylococci, staphylococcus aureus (esp. in nasal carriers, propionibacterium species

Question 17

what is the flora near body orifice?

Answer 17

similar to those in the orifice

Question 18

what are some examples of normal mouth flora?

Answer 18

anaerobes, viridan/oral steptococci

Question 19

what are some examples of normal nasopharyngeal flora?

Answer 19

nostrils - skin flora, Straphycoccus aureus

pharynx - respiratory - streptococcus pyogenes, haemophilius influenzae, streptococcus pneumoniae, neisseria meningitidis, straphycoccus aureus

Question 20

what are some examples of normal stomach and small intestine flora

Answer 20

low pH - less bacterial growth, mainly aerobic bacteria

acid-tolerant lactobacilli, H.pylori

Question 21

what are some examples of normal stomach and large intestine flora

Answer 21

95-99% anaerobes - bacteroide spp., clostridium spp., difidobacteria spp.

aerobic bacteria - enteric gram -ve bacilli - E. Coli, klebsiella spp., enterobacter spp. protues spp. etc

Question 22

what are some examples of normal vaginal flora

Answer 22

pre-puberty - skin flora, lower GI flora (E.Coli)

post-puberty - glycogen produced due to circulating oestrogens - lactobacillus spp. lactobacillus acidophilus, skin flora, C. albicans

Question 23

what are some of the benefits of normal flora

Answer 23

• synthesis and excretion of vitamins - vitamin K and B12 secreted by enteric bacteria
• colonisation resistance - less possible opportunity for outsider bacteria to colonise
• induction of cross-reactive antibodies - may have a protective effect

Question 24

what is one possible treatment for C.diff infection

Answer 24

faecal transplant

Question 25

how can normal flora cause diseases?

Answer 25

overgrowth of normal flora, translocation of normal flora - ie present at the wrong sites, cross-infection

Question 26

which bacteria can cause URTI and conjunctivitis at the same time (translocation)

Answer 26

haemophilius influenzae

Question 27

what can be an example of cross infection of normal flora causing a problem

Answer 27

Meticillin-resistanc S.aureus