Anaerobes Flashcards
Any organism that cannot grow on a non-nutrient deficient medium in an aerobic or CO2 atmosphere but will grow in an oxygen-free atmosphere
Anaerobe
Strict anaerobes lack this enzyme, which in aerobes protects them against ________.
superoxide dismutase
superoxide
Where do anaerobes live outside the body?
Soil, fresh and saltwater
Where do anaerobes live in the body?
GI tract, genitourinary orifices, skin
Why can we get anaerobes living on mucosal surfaces?
Due to laminar flow - barely any air flows at the extremities, and thus anareobes can survive
Most of the anaerobes that cause infection are from where?
Endogenous - something happens that causes our own anaerobes to get to the wrong spot
Anaerobic infections are typically ________, so are properly termed ______ infections since they also contain _______.
polymicrobial
mixed
aerobes
What are clinical clues to anaerobic infection?
Foul odour to lesion or discharge
Infection located in proximity to mucosal surfaces
Bite wounds
Gas in tissues or discharges
Mixed organisms seen on gram stain fail to grow in aerobic culture
What type of abscesses commonly involve anaerobes?
Brain abscesses, dental abscesses, lung abscesses
Which intraabdominal infection is not due to anaerobes?
Spontaneous peritonitis
Breast abcesses due to anaerobes are generally localized where?
Below the nipple (areola)
What are infections that seldom involve anaerobes?
Meningitis acute sinusitis and otitis pharyngitis bronchitis acute cholecystitis spontaneous peritonitis UTIs acute osteomyelitis
What are guidelines for anaerobic specimen collection?
- Specimen must not be contaminated with normal flora (will be loaded with anaerobes - i.e. cannot isolate)
- The specimen to be sent to the lab must be protected from exposure to air
Why can you just send the pus in a container for bacteriology?
The entire pus will maintain anaerobic conditions in any container.
What is the most important thing to do when treating abscesses?
Surgical debridement, drainage and elimination of dead space
How do antibiotics play into treatment of abcesses?
Indicated in the majority of cases - whether or not surgery has been indicated
In normal patients, anaerobes above the diaphragm are ________ _________ and those below it are __________ ________.
penicilin susceptible
penicillin resistant
Large gram-positive spore-forming rod genus.
Clostridium
What are the different Clostridiums that we are going over?
C. tetani
C. botulinum
C. perfringens
C. difficile
Intermittent tonic spasms of voluntary muscles caused by plasmid-encoded protein
Tetanus
What is the plasmid encoded exotoxin that causes tetanus?
Tatanospasmin
Paralysis due to tetanus is due to what?
Muscles are so tight that you cannot move
Tetanus may follow from fairly trivial wounds after about - days.
5-10
Which nerves go into spasm first in tetanus? Why? What is the clinical manifestation?
Cranial nerves b/c they are the smallest
lockjaw = trismus
What is the medical word for lock-jaw?
Trismus
What is risus sardonicus?
Mouth in involuntary smile, associated with tetanus
spasm of the muscles causing backward arching of the head, neck, and spine
opisthotonus in severe tetanus
Clostridium tetani has what type of spores?
Terminal spores
What is the key to tetanus prevention?
Immunization - antibodies neutralize the toxin before it fixes to nerve synapses
What happens once the toxin is fixed to a nerve synapse?
it cannot be neutralized
What is the treatment of tetanus?
Intensive medical support with surgical excision of the injured tissue, administration of penicillin and TIG
What is TIG?
hyperimmune globulin
What type of paralysis does C. botulinum cause?
Flaccid paralysis (have to put on respirator if very severe)
What are the different forms in which the botulism toxin can be found?
Preformed - foodborne botulism
Elaborated from wound infections - wound botulism
Enteric infections - infant botulism, adult colonization botulism
One case of botulism constitutes what?
an outbreak and is considered an emergency
Botulism toxin is what? (how strong)
Very potent - remember the ink blot and mice killing
What are most cases of C. botulinum due to?
From improper home canning, especially alkaline foods
Bacteria, in general, won’t grow in what conditions?
acidic
Why is it difficult to detect C. botulinum?
No smell emanating, no gas - no indication of something wrong in contaminated food
Why should kids under the age of 1 not be fed honey?
B/c it may contain C. botulinum spores
What procedures reduce C. botulinum mortality to less than 25%?
Respiratory support and antitoxin therapy
How is the C. botulinum toxin used cosmetically?
Botox
