Laboratory Guidelines (Reference Document for Survey)

Attachment D: CRE Instrument Attachment Laboratory Guidelines

Form Approved
OMB No. 0920-0879
Expiration Date 01/31/2021

CLSI M100 ED30:2020 – Performance Standards for Antimicrobial Susceptibility Testing, 30th Edition.
Table 1. MIC Breakpoints and Zone Diameter Breakpoints for Enterobacterales, including E. coli, Salmonella,
Klebsiella, Enterobacter, Citrobacter, Providencia, Proteus, and Morganella.
Antimicrobial
Agent

Disk
Content

Resistant MIC
Breakpoints, µg/mL

Doripenem
Ertapenem
Imipenem
Meropenem

10 µg
10 µg
10 µg
10 µg

≥4
≥2
≥4
≥4

Resistant Zone
Diameter Breakpoints,
nearest whole mm
≤19
≤18
≤19
≤19

Adapted with permission from Clinical and Laboratory Standards Institute from: CLSI. Performance Standards for Antimicrobial Disk and
Dilution Susceptibility Tests for Bacteria Isolated From Animals. 4th ed. CLSI supplement VET08. Wayne, PA: Clinical and Laboratory
Standards Institute; 2018.

Table 2. MIC Breakpoints and Zone Diameter Breakpoints for Pseudomonas aeruginosa.
Antimicrobial Disk
Agent
Content

Resistant MIC
Breakpoints, µg/mL

Doripenem
Imipenem
Meropenem

≥8
≥8
≥8

10 µg
10 µg
10 µg

Resistant Zone
Diameter Breakpoints,
nearest whole mm
≤15
≤15
≤15

Adapted with permission from Clinical and Laboratory Standards Institute from: CLSI. Performance Standards for Antimicrobial Disk and
Dilution Susceptibility Tests for Bacteria Isolated From Animals. 4th ed. CLSI supplement VET08. Wayne, PA: Clinical and Laboratory
Standards Institute; 2018.

Table 3. MIC Breakpoints and Zone Diameter Breakpoints for Acinetobacter spp.
Antimicrobial Disk
Agent
Content

Resistant MIC
Breakpoints, µg/mL

Doripenem
Imipenem
Meropenem

≥8
≥8
≥8

10 µg
10 µg
10 µg

Resistant Zone
Diameter Breakpoints,
nearest whole mm
≤14
≤18
≤14

Adapted with permission from Clinical and Laboratory Standards Institute from: CLSI. Performance Standards for Antimicrobial Disk and
Dilution Susceptibility Tests for Bacteria Isolated From Animals. 4th ed. CLSI supplement VET08. Wayne, PA: Clinical and Laboratory
Standards Institute; 2018.

CLSI VET08 ED4:2018 – Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for
Bacteria Isolated from Animals, 4th Edition.
Table 4. MIC Breakpoints and Zone Diameter Breakpoints for Enterobacteriaceae, including E. coli, Salmonella,
Klebsiella, Enterobacter, Citrobacter, Providencia, Proteus, and Morganella.
Test/Report
Group

Antimicrobial Disk
Agent
Content

Humans

Imipenem

10 µg

Resistant MIC
Resistant Zone
Breakpoints, µg/mL Diameter
Breakpoints,
nearest whole mm
≥4
≤19

Adapted with permission from Clinical and Laboratory Standards Institute from: CLSI. Performance Standards for Antimicrobial
Susceptibility Testing. 30th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2020.

Table 5. MIC Breakpoints and Zone Diameter Breakpoints for Pseudomonas aeruginosa.
Test/Report
Group

Antimicrobial Disk
Agent
Content

Humans

Imipenem

10 µg

Resistant MIC
Resistant Zone
Breakpoints, µg/mL Diameter
Breakpoints,
nearest whole mm
≥8
≤15

Adapted with permission from Clinical and Laboratory Standards Institute from: CLSI. Performance Standards for Antimicrobial
Susceptibility Testing. 30th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory Standards Institute; 2020.

The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs
and zone diameters. Version 10.0, 2020.
Table 6. MIC Breakpoints and Zone Diameter Breakpoints for Enterobacteriaceae, including E. coli, Salmonella,
Klebsiella, Enterobacter, Citrobacter, Providencia, Proteus, and Morganella.
Antimicrobial Disk
Agent
Content

Resistant MIC
Breakpoints, µg/mL

Ertapenem
Imipenem

10 µg
10 µg

>0.5
>4

Resistant Zone
Diameter Breakpoints,
nearest whole mm
<25
<17

Meropenem

10 µg

>8

<16

Adapted from The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone
diameters. Version 10.0, 2020.

Table 7. MIC Breakpoints and Zone Diameter Breakpoints for Pseudomonas aeruginosa.
Antimicrobial Disk
Agent
Content

Resistant MIC
Breakpoints, µg/mL

Imipenem

10 µg

>4

Resistant Zone
Diameter Breakpoints,
nearest whole mm
<20

Meropenem

10 µg

>8

<18

Adapted from The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone
diameters. Version 10.0, 2020.

Table 8. MIC Breakpoints and Zone Diameter Breakpoints for Acinetobacter spp.
Antimicrobial Disk
Agent
Content

Resistant MIC
Breakpoints, µg/mL

Imipenem

10 µg

>4

Resistant Zone
Diameter Breakpoints,
nearest whole mm
<21

Meropenem

10 µg

>8

<15

Adapted from The European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone
diameters. Version 10.0, 2020.