ESBL, MBL and Amp C beta lactamase detection DEPARTMENT OF MICROBIOLOGY JIPMER 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, JIPMER 7-Oct-15

List of tests  DETECTION OF EXTENDED SPECTRUM BETA LACTAMASES  ESBL screening test  ESBL combination disc test  DETECTION OF CARBAPENEMASES  Modified Hodge test  EDTA disk synergy test  DETECTION OF Amp C BETA LACTAMASES  Amp C Disk test  Amp C induction by Disk antagonism test XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER 7-Oct-15

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 7-Oct-15

Modified Hodge test 7-Oct-157-Oct-157-Oct-157-Oct-157-Oct-157-Oct-157-Oct-157-Oct-15 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 7-Oct-15 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 disk Negative: zone size < 7 mm or no increase in zone size

Detection of Amp C-β-lactamases by Amp C Disk test 7-Oct-15 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 7-Oct-15 XIII National Workshop on Diagnostic Methods in Clinical Microbiology, JIPMER Cefoxitin disc Blunting zone Ceftazidime disc

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