anaerobes

Question 1

strict anaerobes lack….

Answer 1

superoxide dismutase and catalase

Question 2

can enterococcus and streptococcus grow in anaerobic conditions?

Answer 2

yes. don’t require oxygen but can grow in presence of oxygen

Question 3

how do you get dz from normal flora?

Answer 3

anaerobes= predominant component of human flora

-anything that causes breach of mucosal surfaces

trauma, infection, abcess, etc

Question 4

what type of gross path do anaerobes form?

Answer 4

abcesses, mixed polymicrobial

Question 5

stages of anaerboic abcesses

Answer 5

Acute: aerobes and faculative organisms predominate. Fever, shock, higher mortality

Chronic: fibrin encassed abcesses. Anaerobes. polymicrobial

Question 6

bacteroidies fragilis

Answer 6

• commonly isolated in abccesses BELOW DIAPHRAGM
• colonic
• aerotolerant –> can produce catalase and SOD for a little
• strong capsule
• minor part of normal flora

Question 7

clostridium species

Answer 7

g+ spore forming anaerobes

• dif
• tetani
• botulinum
• perf

Question 8

aerotolerant ANAEROBES vs being “aerotolerant”

Answer 8

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

Question 9

where does tetani like to live?

Answer 9

feces, soil

Question 10

how does tetanus toxin work? what causes death?

Answer 10

RETROGRADE axonal transport to CNS –> inhibits inhibitory neurons (GABA) –> spastic paralysis, inability to relax.

death due to RESP failure

Question 11

tetanus vaccine? can we have natural immunity?

Answer 11

tetanus toxoid. no natural immunity because dose needed to immunize is larger than dose needed to infect

Question 12

neonatal tetanus, maternal tetanus

Answer 12

infection of umbilical stump
infx of mom following birth

MNT vaccine! preventable.

Question 13

why was MNT vax successful?

Answer 13

• vax mom, protect baby for 6 months
• clean birth practices
• proper cord care to prevent putting babe at risk

Question 14

botulinum

Answer 14

• spores infect food

- pressure req to kill them

Question 15

botulinum toxin

Answer 15

• heat labile

- block transmission of Ach at NMJ –> flaccid paralysis

Question 16

threat of botulism as bioterrorism agent

Answer 16

easy to make
potent, lethal
high demand of healthcare utilites –> ventilators, etc

Question 17

botulinum in adults vs babies

Answer 17

adults ingest PREFORMED TOXIN (already growing in anaerobic canned environment)

babies ingest spore –> grows in gut because lack suff flora

Question 18

c diff EXOtoxins

Answer 18

A –> brush borders, causes watery diarrhea

B –> depolymerizes actin skeletons, causes psuedomembrane formation

Question 19

what does the c diff assay screen for?

Answer 19

TOXIN in stool, NOT patient colonization

Question 20

treatment for c diff

Answer 20

ORAL vanc (poor absoprtion, good for side effects)

metronidazole

Question 21

c perf…

Answer 21

obligate anaerobe
spore former
causes:
- food poisoning (SLOW onset)
- gas gangrene

Question 22

how does gas gangrene present?

Answer 22

creptius on PE

alpha toxin= lectithinase –> cleaves PL and damages membranes –> red cell hemolysis

Question 23

does c perf cause hemolysis

Answer 23

DOUBLE hemolysis

Question 24

tx for c perf gas gangrene

Answer 24

IV Pen G