Metallo ß-Lactamase Production and Antibiotic Suceptibility Pattern of Pseudomonas Aeruginosa Isolated from Clinical Samples

Abstract

Pseudomonas aeruginosa is one of the leading causes of nosocomial infections.Carbapenems are used as the last resort for treatment of multidrug resistant(MDR)gram-negative bacterial infection. Resistance to this life saving drug has been increasingly reported in Pseudomonas which is mainly due to production of metallo β- lactamases. Therefore this present study was conducted with an objective to find the prevalence ofP. aeruginosa in different samples along with their antimicrobial susceptibility profile, find out the burden of MDR among P. aeruginosa and the production of metallo β-lactamases among those isolates. Total of5833samples were analysed, at the microbiology department of Shree Birendra Hospital’s, Chauni, Kathmandu from January 2013 to June2013, for routine culture and antibiotic susceptibility testing. Organisms were identified by conventional microbiological method and antibiotic susceptibility test was performed by Kirby-Bauer disc diffusion method. Metallo β-lactamases(MBLs)were detected by using combined disk test using imipenem with Ethylenediaminetetraacetic acid(EDTA).Out of 5833 samples analysed, 942showed positive growth among which 114 (12.1%) were Pseudomonas aeruginosa. Most of the isolates(95.6%)were sensitive to Imipenem and highest resistance (57.0%)was observed towards Ceftadizime. Only 33.3% of P. aeruginosa were multi drug resistant and most were isolated from ICU patients.Prevalence of metallo β- lactamases producing P. aeruginosa strains was 4.4% and all isolates were multi drug resistant.The study showed increasing trend of metallo β-lactamaseproducingisolates indicating the need of routine surveillance and timely control of the spread of these isolates in different units of health institutions. Key words: Pseudomonas aeruginosa, Multi drug Resistance, Metallo β-lactamase