European Journal of Molecular & Clinical Medicine

Abstract

Introduction: Carbapenem  resistance in Enterobacteriaceae is a challenging problem for clinicians. MHT is the CDC recommended screening test with a sensitivity & specificity of >90% . Carbapenems are last resort antibiotics for multidrug-resistant Enterobacteriaceae . However, resistance to carbapenem is increasing at an alarming rate worldwide leading to major therapeutic failures and increased mortality rate. Early and effective detection of carbapenemase producing carbapenem-resistant Enterobacteriaceae (CRE) is therefore key to control dissemination of carbapenem resistance in nosocomial as well as community-acquired infection. The aim of present study was to evaluate efficacy of Modified Hodge test (MHT) for early detection of carbapenemase producing Enterobacteriaceae (CPE).
 
Aim & Objectives:  The aim of the present study to detect carbapenem resistant or carbapenemase production in Enterobacteraceae using MHT.
 
Materials and Methods: Study period was between Feb-April 2014. 100 urine & pus/wound swab samples were  included in the study. Isolates of Enterobacteriaceae were identified to   genus/species level. MBL detection was done for 85 samples as per CLSI  guidelines. 25 were MBL producers. MHT was done for these 25 isolates. 0.5McFarland dilution of E.coli ATCC 25922 in 5ml broth or saline was prepared. Lawn culture of E.coli ATCC 25922 done. Imipenem 10µgm disc was placed in the center. Test organism was streaked from the edge of plate to the edge of the disc & incubated overnight.
 
Results:  In the present study, Isolates included E.coli -54  (64%), Klebsiella spp..- 17 (20%) & Proteus spp..- 14 (16%). Positive MHT had a Clover leaf type indentation at the  intersection of the test  organism and E.coli25922 within the sensitive zone.  Of these 4 (7%) Pseudomonas, 1(6%)  Klebsiella spp. & 1(7%) E.coli spp..  were found to be  Carbapenemase  producers.
 
Conclusion: Although MHT is routinely used, advanced molecular methods is to be done for confirmation which we intend to do in the future. Enterobacteriaceae members are among the most common and easily transferable bacterial species responsible for severe HAI. This study revealed a high percentage of Enterobacteriaceae clinical isolates producing carbapenemases in India. Detection of such bacteria, formulating hospital antibiogram, and monitoring the usage of antimicrobial drugs is recommended.