DRUG RESISTANCE IN ACINETOBACTER SPECIES WITH SPECIAL REFERENCE TO ESBL AND CARBAPENEMASES

Abstract

Background: Acinetobacter species are rapidly emerging nosocomial pathogens mainly affecting patients with impaired host defences. Acinetobacter shows different types of drug resistance. Production of  beta lactamases is the most common mechanism. Detection of these resistance mechanisms is essential to formulate appropriate therapeutic and control measures. Aim: To determine the antibiotic susceptibility pattern of Acinetobacter isolates obtained from clinical samples received in the Department of Microbiology from patients admitted in Government Medical College, Ernakulam and also to identify the mechanism of resistance exhibited by Acinetobacter species in terms of ESBL and Carbapenemases. Materials and Method: This descriptive cross-sectional study included 99 Acinetobacter isolates obtained from samples collected from patients admitted in Government medical college Ernakulam. The isolates whose zone diameters of Ceftazidime less than 22mm and that of Cefotaxime less than 27 mm were considered as potential ESBL producers. ESBL confirmation was done using the double disk diffusion method as per the CLSI guidelines. Carbapenem resistant isolates were subjected to Imipenem-EDTA combined disk test for confirmation of one of the Carbapenemase, Metallo betalactamase production. Genotyping for detection of ESBL and MBL genes was also done. The data entered in the excel spread sheet as per the proforma was analysed using Statistical Package for Social Sciences (SPSS) software 16.0. Chi square test was used in the analysis of study variables. The level of statistical significance was taken as p value <0.05. Result: In our study, 97% of the Acinetobacter  isolates were resistant to Cefotaxime followed by Ceftriaxone(94.9%) and only 41.4% were resistant to Minocycline. Out of the 99 Acinetobacter isolates,  77 (78%) were MDR . 50 (50.5%) isolates were confirmed to be ESBL and 47 (47.5%) isolates were MBL producers . Twenty five (25.2%) isolates had both ESBL and MBL production as the mechanism of resistance. Conclusion: In our study  ,78% of Acinetobacter isolates showed Multi drug resistance. We could demonstrate statistically significant association of multidrug resistance among the Acinetobacter isolates and age above 60 years, ICU admission, immunocompromised state and present antibiotic usage.

Keywords: Acinetobacter isolates; MDR; ESBL; MBL