L10- Normal Microbiota Flashcards Preview

EMS- mod > L10- Normal Microbiota > Flashcards

Flashcards in L10- Normal Microbiota Deck (17):
1

What is Symbiosis

Two or more organisms co-exist in close physical association

2

Symbiosis: What is Mutualism?

Both organisms benefit from symbiosis

3

Symbiosis: What is Neutralism?

Neither organism derives benefit or harm

4

Symbiosis: What is Commensalism?

One organism benefits, the other derives neither benefit nor harm

5

Symbiosis: What is Parasitism?

One organism (parasite) benefits at the expense of the other (host)

6

Do non-sterile sites have normal flora?

Yes
Non-sterile site- Have normal flora (Exposed to the environment)

Sterile sites- No normal flora

7

Sterile site examples...

Lower resp tract: Sterility maintained by surface cleaning

Cervix, Urethra: Sterility maintained by barriers

Spinal cord, Pleural cavity: Sterility maintained by physical separation

8

Examples of Skin flora

Coagulase-negative staphylococci

Staphylococcus aureus (esp. in nasal carriers)

9

Vagina Microbiota Pre puberty vs Post puberty

Pre puberty: Skin flora, Lower GI flora (mainly E. coli)

Post-puberty: Lactobacillus acidophilus (ferment glycogen)
Maintain pH ≈3, preventing overgrowth of other species

10

Anaerobic or aerobic bacteria in stomach + small intestines?

Predominantly aerobic bacteria

11

Anaerobic or aerobic bacteria in large intestine ?

95-99% Anaerobes:
Clostridium

Aerobic bacteria:
Enteric Gram-negative bacilli

12

Benefits of normal flora

Synthesis and excretion of vitamins - e.g. vitamins K and B12 secreted by enteric bacteria

13

Clostridium difficile infection Major risk factor...

ANTIBIOTIC TREATMENT

---> Overgrowth of C.Diff

Leads to toxin production ---> Diarrhoea, Pseudomembranous colitis

14

Pathology of normal flora : Example of Overgrowth

Vaginal thrush

Often treatment with broad spectrum antibiotic can lead to candida infections

15

Pathology of normal flora: Example of Translocation

Conjunctivitis

From one surface to another

16

Pathology of normal flora: Example of Translocation (into a sterile site)

Intravascular catheter infection

Infections associated with intravenous lines often caused by normal flora

17

Pathology of normal flora: Example of Cross-infection

The transmission of an infectious agent from one person to another because of a poor barrier protection as in patients and immunocompromised hosts.