In Vitro Evaluation of Colistin and Ceftazidime-Avibactam Activity Against Multi-Drug Resistant Klebiella Pneumoniae İsolates

Abstract

This study aimed to evaluate the in vitro effectiveness of colistin and ceftazidime-avibactam (CZA) antibiotics against multidrug-resistant (MDR) Klebsiella pneumoniae isolates. The study included 54 clinical isolates sent to the Medical Microbiology Laboratory of Kirsehir Education and Research Hospital between 2022 and 2023, which were resistant to multiple drugs in routine antibiotic susceptibility tests. Colistin susceptibility was evaluated using the microdilution method, while CZA susceptibility was assessed using the disk diffusion method according to the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. It was determined that 31.4% of the isolates were resistant to colistin, and 22.2% were resistant to CZA. No isolates were resistant to both antibiotics. Statistical analyses did not reveal a significant relationship between antibiotic susceptibility and gender, age, underlying disease, and sample type (p>0.05). However, colistin resistance has been found to be higher in intensive care units, whereas resistance to CZA has significantly increased in internal medicine units (p =0.025). The study's findings indicate that colistin and CZA may be important in treating multidrug-resistant K. pneumoniae infections. CZA provides an effective alternative for colistin-resistant isolates, while colistin is an effective alternative for CZA-resistant isolates. However, to enhance the efficacy of these agents, larger-scale studies and ongoing monitoring of resistance mechanisms are necessary.