Emergence of Ceftazidime-Avibactam Resistance in Entero-Bacterales and Pseudomonas Aeruginosa

Abstract

Objective: The objective of this study is to determine the emergence of resistance to Ceftazidime-Avibactam (CAZ-AVI) by Enterobacterales and Pseudomonas aeruginosa in clinical isolates. Material and Methods: In this cross-sectional study (6-months) March-August 2022 Carbapenem resistant Enterobacterales were tested for Ceftazidime-Avibactam (30/20 µg, Oxoid Pvt Ltd) using Disk diffusion technique and enzymes were identified in resistant strains by Carbapenem Inactivation Method (mCIM, eCIM) as per CLSI M100 Guidelines 2022. Results: CAZ-AVI effectiveness has greatly decreased among Enterobacterales and P. aeruginosa isolates in recent past. Antimicrobial susceptibility testing results were interpreted using CLSI M100 document. Resistance against CAZ-AVI in Enterobacterales was found to be 80.8 % in E. coli and 72.1% in Klebsiella pneumonia isolates. This higher emergence is associated with CRE isolates majorly comprising MBLs in our country. Moreover, it has been observed that Metallo- β-lactamases mediated enzyme resistance is one of the major resistance patterns followed by serine carbapenemases. Conclusion: The high frequency of resistance 77% was observed against CAZ-AVI in CRE and in CRPA, the resistance is 80.1% respectively. In our country this tremendously increase in CAZ-AVI resistance is attributed to the existence of NDM in the region. Keywords: Carbapenem Resistant Enterobacterales (CRE), Metallo beta lactamases (MBLs), Carbapenem Resistant Pseudomonas aeruginosa (CRPA) Ceftazidime-Avibactam (CAZ-AVI), Modified Carbapenem Inactivation Method (mCIM), EDTA-modified Carbapenem Inactivation Method(eCIM), Multiple Drug Resistance (MDR)