Investigation of Presence of O25b-ST131 Clone and in Vitro Efficacy of Temocillin in Escherichia coli Isolates

Abstract

Escherichia coli ST131 isolates associated with fluoroquinolone and cephalosporin resistance have increased in the last ten years. This increase has led to the emergence of multidrug-resistant E. coli isolates, resulting in treatment failures for urinary tract infections. The increasing antimicrobial resistance in gram-negative bacteria and the scarcity of new antimicrobials have brought old antimicrobials, such as temocillin, back into consideration. Temocillin has significant advantages and may serve as an alternative to carbapenems in treating serious Enterobacterales infections, such as systemic urinary tract infections. This study aimed to determine the presence of the O25b-ST131 clone in fluoroquinolone-resistant E. coli isolates and assess temocillin resistance. E. coli isolates obtained from urinary tract samples of patients hospitalized in the Faculty of Medicine Hospital of Ondokuz Mayıs University were included in the study. The presence of clone O25b-ST131 in these isolates was investigated using PCR. In addition, temocillin susceptibility in these isolates was determined using the Kirby-Bauer disk diffusion method. According to the PCR results, the prevalence of E. coli O25b-ST131 isolates was 40.8%. The findings of the antimicrobial resistance tests revealed that all isolates had low levels of carbapenem and fosfomycin resistance (2.04% and 3.06%, respectively). The temocillin resistance rate was determined to be 50%. It is known that clone O25b-ST131 is associated with fluoroquinolone and cephalosporin resistance; therefore, a high prevalence of the O25b-ST131 clone was expected in fluoroquinolone-resistant E. coli isolates included in the study. Temocillin is an antimicrobial agent widely used in many European countries, particularly for treating carbapenem-resistant E. coli infections. However, in our study, high rates of temocillin resistance (50%) were observed, despite this agent not being used in our country yet. These high resistance rates could be related to cross-antimicrobial resistance. © 2023 Ondokuz Mayis Universitesi. All rights reserved.