BACTE 7**

The following are factors considered to warrant tests EXCEPT:

Body site

Presence of other bacte

Spn quality

Host status

NOTA

NOTA

T/F

Susceptibility test can be performed even if normal flora is present

False

T/F

The antibiotic needs to access the body site

True

The following are a must in performing susceptibility test EXCEPT

Pure culture

No contaminant

Both

Neither

Neither

The presence numerous colony morphotypes may indicate _____

Heavy contamination

What is used for susceptibility test on immunocompromised hosts

Normal flora

Selecting antimicrobial agents for tests should involve what 3 departments

Lab personnel

Infectious disease

Pharmacy

Susceptibility test method prepared from a single/several isolated colonies of similar morphology

Inoculum preparation

Highly fastidious spn are suspended in the following EXCEPT:

Water

NSS

Broth medium

NOTA

Broth medium

Recommended & most common method for highly fastidious spn

Direct suspension

Which of the following is false:

Inoculum is compared to control

Turbidity of inoculum must match standard

Inoculum must be used within 15 mins

NOTA

Inoculum is compared to control

Inoculum is compared to standard

Standard prepared by adding 1% sulfuric acid & 1.175% barium chloride

McFarland Turbidity solutions

What is used for turbidity standards to provide longer shelf life

Latex particles

Standard comparable to bacterial suspension of 1.5×10^8 CFU/ml

McFarland 0.5 standard

Newer preparations use latex particles instead of _____

Barium sulphate precipitates

What is determined in dilution method

Minimal inhibitory conc (MIC)

Refers to lowest conc of agent required to inhibit growth

Minimum inhibitory conc (MIC)

Broth macrodilution is also known as

Tube dilution

Dilution method using 2 fold serial dilution

Broth macrodilution

Broth macrodilution must attain final conc of

5×10^5 CFU/ml

The gold standard dilution method

Broth dilution

What does broth microdilution use in place of test tubes

Microtiter plates

2 difficulties of broth dilution

Trailing growth

Skipped wells

Refers to 80% reduction in MIC

Trailing growth

Error in preparation, small resistant population, & contamination can cause ____

Skipped wells

Series of plates containing various conc of antimicrobial inoculated with test bacte

Agar dilution test

An example of multi pronged replicating device

Steer’s replicator

Swabbing standardized inoculum & applying disks containing single conc of antibiotics

Disk diffusion/kirby bauer

Agar used in kirby bauer test

Mueller Hinton agar (4mm deep)

When are zones of inhibition read

After overnight incubation

Most common & versatile non automated dilution method

Kirby bauer

Are resistant to erythromycin & susceptible to clindamycin

S. aureus

Erythromycin & clindamycin are placed ____ mm apart

15-26

Indicates inducible clindamycin resistance & isolate is reported clindamycin resistant

D zone of inhibition