Study on Ceftazidime-Avibactam with Aztreonam combination in Carbapenem-resistant Klebsiella pneumoniae using disc diffusion, MIC, Rapidec® Carba Np test, and E-strip in tertiary care hospital in India

Background and Objective: In recent years, the rise of various carbapenemases in Enterobacteriaceae poses a significant challenge to healthcare systems and limits the treatment options This study aims to evaluate the disc diffusion, Vitek, Rapidec® Carba NP test for carbapenemase detection, and investigate the synergistic effects of ceftazidime-avibactam and aztreonam combination therapy using the E-strip method. Methods: From January ۲۰۲۳ to February ۲۰۲۴, a prospective study was conducted at the Department of Microbiology, Central Laboratory Sree Balaji Medical College and Hospital Chennai. Isolates were cultured and identified using standard biochemical methods followed by antibiotic susceptibility testing (AST) both by Kirby Bauer disc diffusion (DD) and the VITEK®۲ system. The performance of the Rapidec® Carba NP test in detecting carbapenemases was observed. The efficacy and potential synergistic effects of the combination comprising ceftazidime-avibactam with aztreonam were performed using the E-strip gradient stacking method. Results & Conclusion: AST results showed the highest resistance rates for ampicillin(۷۸%), followed by amoxicillin/clavulanic acid(۵۲%), meropenem(۵۶%), imipenem (۵۶%), cefazolin (۵۶%), and ciprofloxacin (۵۳%). The lowest resistance rates were found for gentamicin(۲۳%), cotrimoxazole(۲۷%), piperacillin/tazobactam(۲۷%), and tobramycin(۳۳%). Rapidec® Carba NP test detected ۶۵, resulting in a sensitivity of ۹۷% for carbapenemase detection. For Carbapenem-resistant Klebsiella pneumoniae isolates, synergy was observed between CAZ/AVI E-strip and ATM E-strip in ۶۶(۹۸.۷۵%) out of ۶۷ isolates. The Rapidec® Carba NP test remains a valuable tool for initial screening, providing timely information for clinicians. The high rate of synergy observed in our study suggests that CAZ/AVI and ATM will provide a promising treatment option for CRKP infections, particularly in settings with limited therapeutic alternatives.

کلیدواژه ها:

Carbapenemase-resistant Klebsiella pneumoniae ، Ceftazidime-Avibactam with Aztreonam combination ، Rapidec® Carba NP test ، MIC ، Minimum Inhibitory Concentration