Comparative in-vitro activity of cefoperazone-tazobactam and cefoperazone-sulbactam combinations against ESBL pathogens in respiratory and urinary infections.

BACKGROUND The emergence and subsequent widespread dissemination of bacterial resistance to a variety of beta-lactam antibiotics by the elaboration of ESBL (Extended Spectrum Beta Lactamase) poses a serious threat to the effective use of beta lactam antibiotics and cephalosporins. Cefoperazone combination with the beta lactamase inhibitor tazobactam would be a strong basis for rational therapeutics when dealing with ESBL producing pathogen mediated infections. OBJECTIVE The objective of the study was to investigate the in vitro efficacy of cefoperazone-tazobactam and cefoperazone-sulbactam against ESBL producing respiratory and urinary pathogens. METHODOLOGY 54 samples (34 samples of urine and 20 samples of sputum) were collected from 9 hospitals in Mumbai. The pathogens isolated from urine included E. coli (n = 27), K. pneumoniae (n = 6), and Serratia marcescens (n = 1). The pathogens isolated from sputum included Pseudomonas aeruginosa (n = 5), Streptococcus pneumoniae (n = 1) and Klebsiella pneumoniae (n = 14). The Kirby Bauer disc diffusion method was used to evaluate the susceptibility of the isolated pathogens to cefoperazone-tazobactam and cefoperazone-sulbactam. RESULTS In sputum samples, all the isolates of Pseudomonas aeruginosa were susceptible to cefoperazone-tazobactam while one isolate was resistant to cefoperazone-sulbactam. Streptococcus pneumoniae and Klebsiella pneumoniae were sensitive to both the antibiotic formulations. In uropathogens, higher susceptibility rates to cefoperazone-tazobactam (96% vs. 89%) were observed for Escherichia coli. Similarly higher rates of susceptibility to cefoperazone-tazobactam were observed for Klebsiella as compared to cefoperazone-sulbactam (83% vs. 67%). Serratia marcescens was sensitive to cefoperazone-tazobactam but was intermediate resistant to cefoperazone-sulbactam. The isolates of Klebsiella pneumoniae that were resistant to cefoperazone-sulbactam were susceptible to cefoperazone-tazobactam. CONCLUSION The results of the current in vitro study corroborate the efficacy of the beta lactamase inhibitor tazobactam in improving the spectrum of activity and efficacy of cefoperazone.