Validation of the simplified carbapenem inactivation method for detection of carbapenemase producing gram negative rods at the Medical Microbiology Laboratory

Abstract

Purpose: The purpose of the study was to validate the simplified Carbapenem inactivation method by determining the sensitivity and the specificity, this test is more reliable and time consuming compared to the modified Carbapenem inactivation method which involves incubation for 4 hours. Problem: Carbapenem resistance in enterobacteriaceae is the most serious contemporary antibiotic resistance threat because of the number of different resistance mechanisms, concomitant resistance to all or nearly all alternative antibiotics, high mortality associated with invasive infection, and the ability of these pathogens to spread rapidly across geographic regions. To reduce the effects of this resistance to people, a fast and convenient method which is accurate, highly sensitive and reliable must be employed to detect Carbapenemase production. Method: a qualitative experimental study was carried out where results obtained and put in a contingency table. Results: sensitivity=42.9%, specificity=100%, positive predictive value=100%, negative predictive value=27.8%, false positive rate=00%, false negative rate=70% and accuracy=44.7%. Conclusion: On validation of sCIM, gold standard isolates from PCR are used however the isolates should be tested in a short period without being kept in the freezer for a long time because it can result into transposon mediated genes. Imipenem discs should also be used instead of meropenem for accurate results to be obtained