Anaerobes and Biofilms Flashcards
1
Q
Toxic products and free radicals
A
superoxide, hydrogen peroxide, and hydroxyl radical
2
Q
Party animals
A
Sites colonize with mixtures of organisms frequently provide conditions favorable to the growth of anaerobes
-Volatile and foul-smelling metabolic byproducts
3
Q
Oral anaerobes
A
- fusbacterium
- veilonella
- actinomyces
- porphyromonas
- prevotella
4
Q
skin anaerobes
A
propionibacterium
5
Q
Vaginal anaerobes
A
- Lactobacillus
- prevotella bivia
6
Q
Colon anaerobes
A
Bacteroides spp.
7
Q
spore-forming gram pos rods
A
- c. tetani - tetnaus
- c. perfringenes - gas gangrene
- c. botulinum - botulism
- c. difficile - diarrhea
8
Q
nonspore-forming gram pos rods
A
- Actinomyces
- sinus tracts and fistulae
- Sulfur granules - Propionibacterium
- p. acnes, normal skin flora - Mobiluncus
- synergistically with organisms including Gardeneella vaginosis to cause bacterial vaginosis
9
Q
Gram pos cocci
A
- peptostreptococcus
- found in abscesses - brain or deep lung - anaerobic and microaerophillic street spp.
- do not respond well to metronidazole
10
Q
Gram neg cocci
A
- veillonella spp.
- found in mixed infection of oral origin
11
Q
Gram neg rods
A
- bacteroides
- account for 70% of clinically significant anaerobic bacteremia . - Prevotell and porphyromonas
- include former pigmented bacteroides species. common in mouth flora and dental abscess - Fusobacterium
- can also be found with mixed actinomyes spp.
12
Q
Treatment for anaerobes
A
- create an environment in which anaerobes cannot proliferate
- arrest the spread of anaerobes into healthy tissue
- neutralize toxins
13
Q
Stages of biofilm formation
A
- attachment (sec)
- reversibel binding
- log growth
- pili and bacterial adhesion molecules
- change in gene expression - irreversible binding (min)
- EPS trap nutrients and planktonic bacterio
- cells are sessile - Layering/maturation
- greater than 10 microns thick - ultimate thickness/maturation (days)
- greater than 100 microns thick
- some cells released from substrate, but trapped in EPS - Dispersion (several days)
- cells leaving
- as nutrition becomes scarce, there are changes in gene expression
- cells again become planktonic
14
Q
Advantages to living in Biofilm
A
- protection form host defenses
- physical barrier to PMNs/phagocytes
- potetnial to out-compete normal biota
- gene transfer spread resistance in community
- provide protective enzymes
- perform as organic polymers: “creeping”
15
Q
Primary colonizers
A
strept mutans and actinomyces
