ESBL, MBL and Amp C

beta lactamase detection

DEPARTMENT OF MICROBIOLOGYJIPMER

PUDUCHERRY

Objective

• To understand the action of ESBL, Carbapenemases and Amp C beta lactamase and to perform the mentioned tests hands on and interpret the results

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

List of tests

DETECTION OF EXTENDED SPECTRUM BETA LACTAMASESESBL screening testESBL combination disc test

DETECTION OF CARBAPENEMASESModified Hodge testEDTA disk synergy test

DETECTION OF Amp C BETA LACTAMASESAmp C Disk testAmp C induction by Disk antagonism test

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMERApr 21, 2023

Ceftazidime plus Clavulanic acid

Ceftazidime

ESBL disc synergy test

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

The test organism is considered to produce ESBL if the zone size around the ceftazidime plus clavulanic acid increased >5 mm in comparison to (Ca) disk alone

Apr 21, 2023

Modified Hodge test

XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Test strain

Indentation (clover leaf shaped zone of inhibition)

Imipenem

ATCC E.coli lawn culture

Positive: Presence of ‘cloverleaf shaped’ zone of inhibition.Negative: Undistorted zone of inhibition around the imipenem disc.

EDTA disk synergy test

Apr 21, 2023 XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Imipenem Imipenem + EDTA

Positive: increased zone size of >/=7 mm in the imipenem-EDTA disk compared to imipenem diskNegative: zone size < 7 mm or no increase in zone size

Detection of Amp C-β-lactamases by Amp C Disk test

Apr 21, 2023 XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Blank disc with test strain

Cefoxitin disc

Blunting zone

Positive test appear as a flattening or indentation of the cefoxitin inhibition zone in the vicinity of the disk test.Negative disk has an undistorted zone.

ATCC E.coli lawn culture

Amp C induction by Disk antagonism test

Apr 21, 2023XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER

Cefoxitin disc

Blunting zone

Ceftazidimedisc

THANK YOU