CSMLS EXAM
MICROBIOLOGY
LATEST VERSION WITH VERIFIED
CORRECT ANSWERS
,if there is no zone of inhibition, what do you record? - CORRECT ANSWER -
6mm because that accounts for the disc
what causes sharp irregular zones around the sensitivity discs? - CORRECT
ANSWER - beta-lactam antibiotics
- indicates that beta-lactamase production by the bacteria and should be
interpreted as resistant
susceptible vs intermediate vs resistant - CORRECT ANSWER - - susceptible =
susceptible to action of the antimicrobials and is stopped or killed by it
- intermediate = used for certain drug combinations that are difficult to test or
produce results of certainty
- resistant = resistant to the action of antimicrobial and keeps growing in its
presence
QC for susceptibility tests - CORRECT ANSWER - - each time new discs or panels
are received
,- each time tests are performed (once a week)
- organisms are staph aureus, E.coli, pseudo, enterococcus
how should antimicrobial discs be stored? - CORRECT ANSWER - - long term =
frozen at -20C
- working supply in 4C
MRSA conditions - CORRECT ANSWER - - addition of NaCl
- 30-35C (lower temp is better)
- displays trailing on disc diffusion methods
- healthcare workers are screened for it
- use oxacillin screen test
Haemophilus test medium (HTM) is supplemented with - CORRECT ANSWER - -
bovine hematin
- yeast extract
- NAD
- thymidine phosphorylase
E-test is beneficial for using it on - CORRECT ANSWER - - anaerobes
, - fastidious bacteria
E-test results interpretation: low MIC and high MIC - CORRECT ANSWER - low
MIC - sensitive
high MIC - resistant
Staphylococcus aureus characteristics - CORRECT ANSWER - - double zone of
beta hemolysis
- creamy yellow color from lipochrome @48H
- ferments mannitol (yellow)
- catalase positive
- nitrate positive
- slide or TUBE coagulase positive
MSA media (mannitol salt agar) - CORRECT ANSWER - - 7.5% NaCl
- differential = mannitol and phenol red
- if it ferments mannitol it will be yellow, if it does not then it will be red
- staph aureus ferments (yellow)
MICROBIOLOGY
LATEST VERSION WITH VERIFIED
CORRECT ANSWERS
,if there is no zone of inhibition, what do you record? - CORRECT ANSWER -
6mm because that accounts for the disc
what causes sharp irregular zones around the sensitivity discs? - CORRECT
ANSWER - beta-lactam antibiotics
- indicates that beta-lactamase production by the bacteria and should be
interpreted as resistant
susceptible vs intermediate vs resistant - CORRECT ANSWER - - susceptible =
susceptible to action of the antimicrobials and is stopped or killed by it
- intermediate = used for certain drug combinations that are difficult to test or
produce results of certainty
- resistant = resistant to the action of antimicrobial and keeps growing in its
presence
QC for susceptibility tests - CORRECT ANSWER - - each time new discs or panels
are received
,- each time tests are performed (once a week)
- organisms are staph aureus, E.coli, pseudo, enterococcus
how should antimicrobial discs be stored? - CORRECT ANSWER - - long term =
frozen at -20C
- working supply in 4C
MRSA conditions - CORRECT ANSWER - - addition of NaCl
- 30-35C (lower temp is better)
- displays trailing on disc diffusion methods
- healthcare workers are screened for it
- use oxacillin screen test
Haemophilus test medium (HTM) is supplemented with - CORRECT ANSWER - -
bovine hematin
- yeast extract
- NAD
- thymidine phosphorylase
E-test is beneficial for using it on - CORRECT ANSWER - - anaerobes
, - fastidious bacteria
E-test results interpretation: low MIC and high MIC - CORRECT ANSWER - low
MIC - sensitive
high MIC - resistant
Staphylococcus aureus characteristics - CORRECT ANSWER - - double zone of
beta hemolysis
- creamy yellow color from lipochrome @48H
- ferments mannitol (yellow)
- catalase positive
- nitrate positive
- slide or TUBE coagulase positive
MSA media (mannitol salt agar) - CORRECT ANSWER - - 7.5% NaCl
- differential = mannitol and phenol red
- if it ferments mannitol it will be yellow, if it does not then it will be red
- staph aureus ferments (yellow)
