Current status of drug resistance among gram-negative bacilli isolated from admitted cases in a tertiary care centre.

AIMS

To study the prevalence of drug resistance among gram-negative bacilli and susceptibility to the Cefoperazone + Sulbactam and Piperacillin + Tazobactam combination among the hospital isolates resistant to all other antimicrobial agents.

METHODS

A total of 367 gram-negative bacilli isolated from various pathological samples were tested for susceptibility to antimicrobial agent by the disc diffusion technique and 300 isolates of gram-negative bacilli which were resistant to all the other antibiotics were checked for sensitivity to piperacillin + tazobactam and cefoperazone + sulbactam combination.

RESULTS

Resistance to ampicillin and amoxicillin + clavulanic acid ranged from (72.1-83.8%) which was highest. Resistance to cotrimoxazole, gentamicin, netilmycin, quinolones and all the generation of cephalsporins was often above 50%. piperacillin + tazobactam combination had the lowest incidence of resistance (14 to 20.5%).

CONCLUSION

Drug resistance for most of the antimicrobial agents was greater than 50% including the various generations of cephalosporins. Inefficiency of amoxicillin + clavulanic acid (resistance among 72-79.5% isolates) suggests the presence of extended spectrum beta-lactamases among the isolates. Addition of sulbactam to cefoperazone showed increased activity (resistance 27 to 34%) but piperacillin + tazobactam was the most effective combination in vitro.