Isolation of Extended Spectrum β-Lactamase Producing Gram Negative Bacilli from Wound Swab with Their Antimicrobial Susceptibility Pattern.

Extended Spectrum β-lactamases (ESBLs) producing organisms have become the major clinical concern worldwide. The present study was undertaken to see the frequency of ESBLs producing gram-negative bacilli with their antibiogram in post surgical wound swab collected over a period of 12 months from July 2011 to June 2012 at Dhaka Medical College Hospital. Among 200 samples 121(60.5%) gram negative bacilli and 52(26%) gram-positive bacteria were isolated. Escherichia coli (36.42%) was the most predominant gram-negative bacilli followed by Klebsiella species (9.83%) and Pseudomonas aeruginosa (8.67%). Thirty four (28.1%) isolates were detected as ESBLs producers by double-disc synergy test (DDST) and the prevalence among Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa were 33.33%, 35.29% and 26.67% respectively. All the ESBL producing strains were sensitive to imipenem but they were significantly more resistant to ciprofloxacin, doxycycline, amoxiclav, co-trimoxazole, azithromycin and gentamycin than non-ESBLs producers (p<0.01). The finding suggests more effective strategies are needed to control the spread of these resistant organisms.