Investigation of the high-risk ST131 clone in clinical Escherichia coli isolates from community-acquired and healthcare-associated infections

Objective: Escherichia coli ( E. coli ) ST131 is a high-risk clone linked to CTX-M betalactamase production and fluoroquinolone resistance. Given the high rates of extended-spectrum beta-lactamase (ESBL) production and ciprofloxacin resistance in Turkey, this study aimed to determine the prevalence of the ST131 clone in clinical E. coli isolates from community-acquired and healthcare-associated infections. Methods: E. coli isolates obtained from various clinical specimens submitted to our laboratory between June and September 2018 were analyzed. Bacterial identification and detection of the ST131 clone were performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Community acquired and healthcare-associated infections were defined according to the Friedman criteria. Our study was designed as a prospective and descriptive study. Results: A total of 700 E. coli isolates were included in the study. Among these, 224 (32%) were identified as ESBL producers, and 240 (34.3%) belonged to the ST131 clone. ESBL production as well as resistance to ciprofloxacin and various other antimicrobials were significantly more frequent among ST131 isolates. Notably, all three carbapenemase-producing isolates were also identified as ST131.The ST131 clone was identified in 34.7% (103/296) of isolates from community-acquired infections and in 33.9% (137/404) of isolates from healthcare-associated infections, with no statistically significant difference between the two groups ( P = 0.807). Conclusion: In conclusion, the ST131 clone was detected at a high rate among clinical E. coli isolates, with comparable frequencies in both healthcare-associated and community-acquired infections. Given its association with ESBL production and multidrug resistance, continuous detection and surveillance of this high-risk clone are essential for guiding effective strategies to control antimicrobial resistance.