Microbiology

Question 1

where would you see haematogenous osteomyelitis and who is it more common in

Answer 1

children with long bones or adult vertebrae

Question 2

when would you see contiguous osteomyelitis and who is it more common in

Answer 2

younger patients with injury/surgery

older patients with vascular insufficiency/pressure sores

Question 3

treu/false - for osteomyelitis the best urgent management is empirical antibiotics

Answer 3

false - never unless the patient is septic

Question 4

microbes in open fracture osteomyelitis

Answer 4

s aureus
gm -ves
polymicrobial

Question 5

microbes in diabetic foot osteomyelitis

Answer 5

polymicrobial, may be faecal bacteria

Question 6

microbes in haematogenous osteomyelitis

Answer 6

staph aureus

Question 7

microbes in sickle cell osteomyelitis

Answer 7

s aureus and samonella

Question 8

unusual osteoomyelitis sites

Answer 8

clavicle

osteitis pubis - athletes and post surgery

Question 9

microbes in vertebral osteomyelitis

Answer 9

staph aureus and coag -ve staph

Question 10

risk factors for vertebral osteomyelitis

Answer 10

PWID 
GU infection 
IV line 
post op
primary bacteraemia

Question 11

true/false - prosthetic joint infections are biofilm forming

Answer 11

true

Question 12

Organisms in prosthetic joint infection

Answer 12

coag -ve staph - post 3 months 
staph aureus - 1-3 months 
propionibacterium acnes 
gram -ves, ecoli, pseudomonas - may be first 3 months or after 
corynebacterium - post 3 months 
cutiibacterium acnes

Question 13

risk factors for prosthetic joint infection

Answer 13

comorbidity
prior arthroplasty
surgical site infection

Question 14

pathology of osteomyelitis

Answer 14

infection begins to form an abscess in blood rich bone and then moves to cortical bone to form sequestrium, and then may form a sinus

Question 15

organisms in pyomyositis

Answer 15

90% staph but in immunosuppressed may be pseudomonas, beta haemolytic strep or enterococcus

Question 16

what microbe may lead to myonecrosis and what does it form in bone

Answer 16

clostridium

gas

Question 17

organisms of septic arthritis

Answer 17

staph aureus 
strep
n gonorrhoea 
h influenzae in school age 
anaerobes

Question 18

cause of tetanus and microbiology

Answer 18

clostridium tetani

gram +ve strict anaerobe rod

Question 19

how does tetanus act to cause disease

Answer 19

neurotoxins from spores bind to inhibitory neurons to prevent neurotransmitter release

Question 20

antibiotic for s aureus

Answer 20

flucloxacillin

Question 21

antibiotic for s epidermidis

Answer 21

vancomycin

Question 22

antibiotic for strep pyrogenes

Answer 22

doxycycline

Question 23

antibiotics for gram -ves

Answer 23

clindamycin

Question 24

antibiotics for anaerobes

Answer 24

co-trimoxazole/metronidazole

Question 25

useful blood tests in osteomyelitis?

Answer 25

blood culture CRP ESR/PV WCC

Question 26

useful imaging in osteomyelitis and downfall?

Answer 26

x rays - has to be advanced MRI - overdiagnoses technetium scan - not any really

Question 27

true/false - blood work is very useful in chronic osteomyelitis

Answer 27

false

Question 28

easily measurable prophylaxis to prevent prosthetic joint infection

Answer 28

clean air theratre local antibiotics in cement systemic antibiotics duration of surgery

Question 29

hard to measure prophylaxis in prosthetic joint infection

Answer 29

theatre discipline time in washing hands surgical technique