anaerobes Flashcards
strict anaerobes lack….
superoxide dismutase and catalase
can enterococcus and streptococcus grow in anaerobic conditions?
yes. don’t require oxygen but can grow in presence of oxygen
how do you get dz from normal flora?
anaerobes= predominant component of human flora
-anything that causes breach of mucosal surfaces
trauma, infection, abcess, etc
what type of gross path do anaerobes form?
abcesses, mixed polymicrobial
stages of anaerboic abcesses
Acute: aerobes and faculative organisms predominate. Fever, shock, higher mortality
Chronic: fibrin encassed abcesses. Anaerobes. polymicrobial
bacteroidies fragilis
- commonly isolated in abccesses BELOW DIAPHRAGM
- colonic
- aerotolerant –> can produce catalase and SOD for a little
- strong capsule
- minor part of normal flora
clostridium species
g+ spore forming anaerobes
- dif
- tetani
- botulinum
- perf
aerotolerant ANAEROBES vs being “aerotolerant”
organisms that can live in presence of oxygen but do not metabolize it
vs orgs like bacteroidies that aerotolerant in that they can survive for short periods of time
where does tetani like to live?
feces, soil
how does tetanus toxin work? what causes death?
RETROGRADE axonal transport to CNS –> inhibits inhibitory neurons (GABA) –> spastic paralysis, inability to relax.
death due to RESP failure
tetanus vaccine? can we have natural immunity?
tetanus toxoid. no natural immunity because dose needed to immunize is larger than dose needed to infect
neonatal tetanus, maternal tetanus
infection of umbilical stump
infx of mom following birth
MNT vaccine! preventable.
why was MNT vax successful?
- vax mom, protect baby for 6 months
- clean birth practices
- proper cord care to prevent putting babe at risk
botulinum
- spores infect food
- pressure req to kill them
botulinum toxin
- heat labile
- block transmission of Ach at NMJ –> flaccid paralysis
threat of botulism as bioterrorism agent
easy to make
potent, lethal
high demand of healthcare utilites –> ventilators, etc
botulinum in adults vs babies
adults ingest PREFORMED TOXIN (already growing in anaerobic canned environment)
babies ingest spore –> grows in gut because lack suff flora
c diff EXOtoxins
A –> brush borders, causes watery diarrhea
B –> depolymerizes actin skeletons, causes psuedomembrane formation
what does the c diff assay screen for?
TOXIN in stool, NOT patient colonization
treatment for c diff
ORAL vanc (poor absoprtion, good for side effects)
metronidazole
c perf…
obligate anaerobe spore former causes: - food poisoning (SLOW onset) - gas gangrene
how does gas gangrene present?
creptius on PE
alpha toxin= lectithinase –> cleaves PL and damages membranes –> red cell hemolysis
does c perf cause hemolysis
DOUBLE hemolysis
tx for c perf gas gangrene
IV Pen G
