IN-VITRO EFFICACY OF PIPERACILLIN/SULBACTAM AGAINST MULTIDRUG-RESISTANT PSEUDOMONAS AERUGINOSA: A COMPARATIVE STUDY WITH PIPERACILLIN/TAZOBACTAM AND CEFOPERAZONE/SULBACTAM

Abstract

Multidrug-resistant (MDR) Pseudomonas aeruginosa represents an important challenge for the treatment of healthcare-associated infections because of its capacity to develop resistance to multiple classes of antimicrobial agents. The organism possesses several mechanisms of resistance, including reduced outer-membrane permeability, active efflux, modification of antibiotic targets, and enzymatic inactivation of antimicrobial agents. The development and use of β-lactam/β-lactamase-inhibitor combinations have therefore become important strategies for improving the activity of β-lactam antibiotics against resistant Gram-negative organisms. This research paper examines the in-vitro efficacy of piperacillin/sulbactam against MDR P. aeruginosa and compares its activity with piperacillin/tazobactam and cefoperazone/sulbactam. The paper is based principally on the uploaded thesis by Ambreen Malik, completed in the Department of Microbiology, Quaid-i-Azam University, Islamabad, in 2012. The original laboratory study was conducted at the Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi. A total of 170 P. aeruginosa isolates recovered from different clinical specimens were examined during three months from April to June 2011. One hundred isolates were identified as multidrug-resistant and selected for further investigation. Identification involved conventional microbiological procedures, while antimicrobial susceptibility was determined through the modified Kirby-Bauer disk diffusion method according to CLSI guidelines. The study compared three β-lactam/β-lactamase-inhibitor combinations: piperacillin/sulbactam, piperacillin/tazobactam, and cefoperazone/sulbactam. The thesis concludes that piperacillin/sulbactam demonstrated effective in vitro activity against MDR P. aeruginosa and merits consideration as an alternative therapeutic combination. The findings also underline the continuing importance of antimicrobial susceptibility testing and surveillance of resistance patterns.