en باکتری شناسی پزشکی Medical Bacteriology مقاله کوتاه پژوهشی Brief Original Article <p style="text-align: justify;"><span style="font-size:16px;"><span style="font-family:Times New Roman;"><span style="line-height:200%"><b><span style="line-height:200%">Background and Objective: </span></b><span style="line-height:200%">Recently, the rise in various carbapenemases in Enterobacteriaceae poses a significant challenge to the healthcare systems and limits the treatment options. This study aimed to evaluate different assays such as disc diffusion, VITEK, and Rapidec&reg; Carba NP test for the carbapenemase detection, and investigate the synergistic effects of ceftazidime-avibactam (CAZ/AVI) and aztreonam (AZM) combination therapy using the E-strip method.</span></span><br> <span style="line-height:200%"><b><span style="line-height:200%">Methods: </span></b><span style="line-height:200%">This prospective study was conducted on the samples collected from January 2023 to February 2024 at the Department of Microbiology, Central Laboratory Sree Balaji, Medical College and Hospital Chennai, India. The isolates were cultured and identified using the standard biochemical methods followed by the antibiotic susceptibility testing (AST) both by Kirby Bauer disc diffusion (DD) and the VITEK^&reg;2 system. The Rapidec&reg; Carba NP test was performed in detecting carbapenemase. The efficacy and potential synergistic effects of the combination treatment comprising CAZ/AVI and AZM were performed using the E-strip gradient stacking method.</span></span><br> <span style="line-height:200%"><b><span style="line-height:200%">Results & Conclusion: </span></b><span style="line-height:200%">According on the<b> </b>AST, the highest resistance rates were detected for ampicillin (78%), then, followed by amoxicillin/clavulanic acid (52%), meropenem (56%), imipenem (56%), cefazolin (56%), and ciprofloxacin (53%). The lowest resistance rates were found for gentamicin (23%), cotrimoxazole (27%), piperacillin/tazobactam (27%), and tobramycin (33%). Rapidec&reg; Carba NP test detected 65 bacterial isolates stored in the laboratory, resulting in a sensitivity of 97% for carbapenemase detection. For&nbsp;carbapenem-resistant Klebsiella pneumoniae (CRKP) isolates, synergy was observed between CAZ/AVI E-strip and AZM E-strip in 66 out of 67 isolates (98.75%).<b> </b>The Rapidec&reg; Carba NP test remains a valuable tool for the initial screening, providing timely information for the clinicians. The high rate of synergy observed in our study suggests that CAZ/AVI and AZM will provide a promising treatment option for the CRKP infections, particularly in the settings with limited therapeutic alternatives.</span></span></span></span></p> Carbapenem-resistant Klebsiella pneumoniae, Ceftazidime-Avibactam with Aztreonam combination, Rapidec® Carba NP test, MIC 257 264 http://ijmm.ir/browse.php?a_code=A-10-2557-1&slc_lang=en&sid=1 Sharon Christina drchristinam@gmail.com 100319475328460029909 0009-0005-3213-6054 Yes Department of Microbiology, Sree Balaji Medical College and Hospital, Bharath Institute of Higher Education and Research, Chennai, India Raveendran Praveena praveena.r@bharathuniv.ac.in 100319475328460029910 100319475328460029910 No Department of Microbiology, Sree Balaji Medical College and Hospital, Bharath Institute of Higher Education and Research, Chennai, India