Carbapenemase genes among multidrug resistant Acinetobacter baumannii in the critical care unit of Kenyatta National Hospital, Kenya

Abstract

Background:The emergence of multidrug resistant A.baumannii as an opportunistic nosocomial pathogen in intensive care units is of great public health concern worldwide. Carbapenems such as meropenem and imipenem have been used as antibiotics of last resort, the main mechanisms of A. baumannii are the production of carbapenemases.
Objective: To investigate the prevalence carbapenemase genes among MDR A.baumannii in clinical isolates from Critical Care Unit of KNH.
Design: December 2014 and May 2015 cross sectional study.At KNH Microbiology and KAVI Institute of clinical Research (KAVI-ICR) laboratories.
Setting: Susceptibility of 53 isolates of MDR A. baumannii from CCU was determined. However only 22 were analyzed for carbapenemase genes due to cost. Real time polymerase chain reaction (RT PCR)) was used to detect the common carbapenemase genes: Veron integrin metallo-beta-lactamases (VIM), imipenemase (IMP) and New Delhi metallo-beta-lactamase (NDM), OXA-48 and Klebsiella pneumoniae carbapenemase(KPC).
Results: The findings indicated high levels of A. baumannii resistance to antibiotics used in CCU. Resistance to meropenemwas 84.9% (n=45) and 73.6% (n=39) to imipenem. Prevalence of carbapenemase genes among MDR A. baumannii isolates was 100% (n=22). The genes were heterogeneously distributed among the isolates. The most predominant carbapenemase gene detected was OXA48 with 100% (n= 22) followed by NDM with 90.9% (n=20).
Conclusion: Carbapenem resistance conferring genes were detected in all multidrug resistant A. baumanii, with OXA48 always present. Strengthening of antibiotic stewardship programs which will contribute to enhancement of infection control policies.