CMS SOM App. C, Tag D5507

(b) For antimicrobial susceptibility tests, the laboratory must check each batch of

media and each lot number and shipment of antimicrobial agent(s) before, or

concurrent with, initial use, using approved control organisms.

(b)(1) Each day tests are performed, the laboratory must use the appropriate

control organism(s) to check the procedure.

(b)(2) The laboratory’s zone sizes or minimum inhibitory concentration for control

organisms must be within established limits before reporting patient results.

Interpretive Guidelines §493.1261(b)(1-2)

“Approved control organism(s)” means either an appropriate control strain or an

equivalent strain as defined below.

The laboratory must ensure proper standardization of the inoculum (e.g., use a 0.5

McFarland standard or its optical equivalent, or follow manufacturer’s instructions for a

commercially available system).

Antimicrobial Disk Diffusion Susceptibility

(Bauer, Kirby, Sherris and Turk Method)

Each new batch of medium and each new lot/shipment of antimicrobial disks must be

checked as follows:

ANTIMICROBIAL DISK SUSCEPTIBILITY TEST

Appropriate Control

Strain

Each New Batch

of Media and Disks

Each Day If Isolates Are:

S. aureus ATCC 25923 or

equivalent**

X Staphylococcus spp.

E. coli ATCC 25922 or

equivalent**

X Enterobacteriaceae

P. aeruginosa ATCC 27853

and E. coli ATCC 25922 or

equivalent**

X Pseudomonas aeruginosa

Acinetobacter spp.

The above table provides guidance to surveyors of the checks required for each new

batch of medium and each new lot/shipment of antimicrobial disks. These must be

checked as follows:

1. S. aureus ATCC 25923 or equivalent must be used to test each new batch of

media or disks and it must be used each day if the isolate is Staphylococcus

ssp.

2. E. coli ATCC 25922 or equivalent must be used to test each new batch of

media or disks and it must be used each day if the isolate is

Enterobacteriaceae ssp.

3. P. aeruginosa ATCC 27853 and E. coli ATCC 25922 or equivalent must be

used to test each new batch of media or disks and it must be used each day if

the isolate is Pseudomonas aeruginosa and/or Acinetobacter spp.

Zone sizes must be recorded for each antimicrobial control and limits must be

established.

**An equivalent strain is one which demonstrates reactivity similar to an ATCC strain

and for which limits have been established. Organisms which manufacturers recommend

or require for use in their systems are acceptable strains of control organisms.

Direct susceptibility testing is a modification of the standardized disk diffusion

susceptibility testing method. Therefore, the laboratory must establish the interpretive

zone diameters for patient specimens, as well as establish the zone diameters for quality

control organisms.

MINIMUM INHIBITORY CONCENTRATION (MIC)

Each new batch of macrodilution tubes, microdilution trays, or agar dilution plates must

be checked as follows:

MINIMUM INHIBITORY CONCENTRATION (MIC)

Appropriate Control

Strain

Each New Batch

of Media

Each Day If Isolates are:

S. aureus ATCC 29213 or

equivalent**

X Staphylococcus spp.

E. coli ATCC 25922 or

equivalent**

X Enterobacteriaceae

P. aeruginosa ATCC 27853

and E. coli ATCC 25922 or

equivalent **

X non-Enterobacteriaceae to include

Acinetobacter spp.,

Stenotrophomonas maltophilia,

Pseudomonas spp. and other

nonfastidious, glucose

nonfermenting, gram-negative

bacilli

E. faecalis ATCC 29212 or

equivalent**

X

Enterococcus spp.

The above table provides guidance to surveyors of the checks required for each new

batch of macrodilution tubes, microdilution trays, or agar dilution plates. These must be

checked as follows:

1. S. aureus ATCC 29213 or equivalent must be used to test each new batch of

media and it must be used each day if the isolate is Staphylococcus ssp.

2. E. coli ATCC 25922 or equivalent must be used to test each new batch of

media and it must be used each day if the isolate is Enterobacteriaceace ssp.

3. P. aeruginosa ATCC 27853 and E. coli ATCC 25922 or equivalent must be

used to test each new batch of media and it must be used each day if the

isolate is non-Enterobacteriaceace to include Acinetobacter ssp.,

Stenotrophomonas maltophila, Pseudomonas spp. and/or other nonfastidious,

glucose nonfermenting, gram-negative bacilli.

4. E. faecalis ATCC 29212 or equivalent must be used to test each new batch of

media and it must be used each day if the isolate is Enterococcus ssp.

**An equivalent strain is one which demonstrates reactivity similar to an ATCC strain

and for which limits have been established. Organisms which manufacturers recommend

or require for use in their systems are acceptable strains of control organisms.

Each day the test is performed, the appropriate control strain(s) must be included to check

the test system.

§493.1261 Standard: Bacteriology.

(c) The laboratory must document all control procedures performed, as specified in

this section.

Interpretive Guidelines §493.1261(c)

QC records should include lot numbers, date prepared/opened, expiration dates, the actual

measurements, reactions, and/or observations and demonstrate that controls were tested

and acceptable when shipments of reagents, disks, stains, or antisera for identification

systems were opened or when the laboratory prepared these materials.