Antimicrobial susceptibility pattern of extended spectrum beta-lactamase producing gram-negative bacteria isolated from wound and urine in a tertiary care hospital, Dhaka City, Bangladesh.

From a total of 320 bacterial samples from wound swab and urine 169 (53%) gram-negative bacteria were isolated, of which 42 (25%) extended-spectrum beta-lactamase (ESBL) producers were detected by double-disk synergy test. ESBL producers were significantly more resistant against amoxiclav, Co-trimoxazole, ciprofloxacin, amikacin and gentamicin than non-ESBL producers. Among the 42 ESBL producers, 76% were positive for blaCTX-M and 43% were positive for blaOXA, with blaCTX-M predominantly (97%) observed in E. coli and blaOXA predominantly (80%) in Pseudomonas spp. Class 1 integron was found in 75% of blaCTX-M positive and 56% of blaOXA positive strains. Combinations of ESBL genes and class 1 integron were observed in 29 (69%) of the ESBL producers. The findings of this study infer that CTX-M and OXA producers are emerging in Bangladesh and we report the presence of blaOXA for the first time in Bangladesh.