Anaerobic Bateria Flashcards
What are the two sources of anaerobic bacteria?
Normal Flora
Soil
What are some Normal Flora anaerobes?
Actinomyces, B. corrodens, P. melaninogenica
–>Mouth
B. fragilis–> Colon and Vagina
What is caused by the normal flora?
When escape compartments –> abscess (es)–> fill with bacteria/dead neutrophils–>swell–>become painful
What are the two routes of entry in anaerobic bacteria that come from soil?
A-Spores enter through wounds, germinate, and produce exotoxins
B-Spores germinate in vacuum-packed foods
What are some soil anaerobic bacteria that use route A?
C. tani in tetanus
C. perfrigens in gas gangrene
C. botulinum in wound botulism
What are some soil anaerobic bacteria that use route B?
C. perfrigens in food poisoning
C. botulinum in infant botulism
C. botulinum in foodborne botulism
What happens in C. perfrigens in food poisoning
bacteria briefly survive in gut and release enterotoxin
What happens in C. botulinum in infant botulism
bacteria briefly survive in gut and release neurotoxin
What happens in C. botulinum in foodborne botulism
bacteria DO NOT survive in gut, but have already filled food with neurotoxin
How would you handle anaerobes in the laboratory?
Must be handled anaerobically and labelled as such
Keep away from O2
What are some laboratory test that can be done?
Anaerobic Cultures
Gram Stain
Gas chromatography
How to do a simple liquid culture is anaerobe?
Incoluate test tube Add reducing agent to eliminate O2 thyoglycolate Fill tube COMPLETELY Stopper tightly Incubate
What are the four types of anaerobic bacteria?
Clostridium - 4 sub groups - gram +, spore forming, rods
Bacteroides - gram -, rods
Prevotella - gram -, rods
Actinomyces - gram +, filamentous rods
What is GNAB?
It is the grouping of Bacteroides and Prevotella, it stands for Gram Negative Anaerobic Bacteria
About Clostridium tetani
Responsible for tetanus
Spores are environmental
Gram +, spore forming
Transmitted to human through soil contamination of wounds
What are the steps to C. tetani infection?
Insertion of bacteria beneath skin surface - limits air contact
Spores germinate inside the wound
Vegetative cells release the exotoxin TETANOSPASMIN
What happens after tetanospasmin is released?
B delivers the toxin A to the site of toxicity
B takes A to motor neurons
B creates a pore in the neuron which A enters through
A travels to the CNS using the retrograde axonal transport
A acts as a peptidase and cleaves SYNAPTOBREVIN
What does the cleavage of SYNAPTOBREVIN do?
Their is a loss of central inhibitory activity on motor and autonomic neurons - spasms
What is generalized tetanus?
Tetanospasmin enters the bloodstream
FULL-BODY symptoms–>morbidity occurs
->50% untreated
->21-31% treated
How can you prevent C. tetani?
Universal vaccination with tetanus toxoid in childhood, and boosters every 10 yrs as adults
C. difficile bacteriology?
Gram +, spore forming, rods
Most commonly causes Pseudomembranous colitis
What is the mode of transmission of C. difficile?
3%-Normal Flora in normal pop
30%-Normal Flora in hospital pop
Fecal-oral
Why does C. difficile come about?
Due to a recent course of antibiotics/cancer treatment that suppresses other normal flora and allows C. difficile to overgrow
The germinating cells release Exotoxin A
Exotoxin B is the major toxin
What does Exotoxin A do?
disrupts tight junctions–>internal swelling and inflammation
