PREVALENCE OF METALLO β LACTAMASES PRODUCING PSEUDOMONAS SPP. AND ACINETOBACTER SPP. IN A TERTIARY CARE TEACHING HOSPITAL
INTRODUCTION: Metallo β lactamases (MBL) are metallo enzymes of Ambler class B and are resistant to clavulanic acid. They require zinc as co-factor for enzymatic activity and their activity is inhibited by ethylene diamine tetra acetic acid (EDTA) and other metal ion chelating agents. The present study was undertaken to determine the multidrug resistance pattern and the prevalence of MBL in Pseudomonas spp. and Acinetobacter spp. in a tertiary care teaching hospital.
Materials and Methods: The present study was carried out in the Department of Microbiology, Vydehi Institute of Medical Sciences and Research Centre, Bangalore from January 2014-December 2014. Consecutive 200 multidrug resistant isolates of Pseudomonas spp. and Acinetobacter spp were isolated and identified by standard microbiological procedures. Antimicrobial susceptibility testing was carried out by Kirby Bauer disc diffusion method and MBL detection was done by Imipenem / Imipenem+EDTA disc diffusion method and E strip method for Imipenem / Meropenem resistant isolates.
RESULTS: Prevalence of MBL production in Pseudomonas spp and Acinetobacter spp was 29.5%. MBL producer were seen in 16 out of 25 (64%) isolates of Acinetobacter spp. whereas in Pseudomonas spp. 43 of 175 (24.6%) isolates showed MBL production. Highest prevalence of MBL was found in aspirated fluid (n=1,100%) pleural fluid (n=1,100%), urine (n=8, 47.1%) followed by pus, catheter tip, blood, BAL fluid and sputum. The maximum MBL was found in the age group 0-5, 11-18 and then > 60 years. The highest number of MBL production was observed in Orthopaedic wards followed by surgical wards and then ICUs.
CONCLUSIONS: The prevalence of MBL production was more in Orthopaedic wards, surgical wards and ICUs suggesting nosocomial occurrence of infections due to hospital stay. The emergence of MBL and their broad spectrums and unrivalled drug resistance is creating a therapeutic challenge for clinicians and microbiologists.
KEY WORDS: Pseudomonas aeruginosa, Acinetobacter baumannii, MBL