High Occurrence of ST131 Among Extraintestinal Pathogenic Escherichia coli in Humans and Dogs in Sri Lanka.

Abstract

AIMS: Extraintestinal pathogenic Escherichia coli (ExPEC) is an important human and animal pathogen. In particular, the ST131 of ExPEC is a widely distributed clone, resistant to extended-spectrum cephalosporins and fluoroquinolones. We investigated the occurrence of ST131 among ExPEC from humans and dogs in Sri Lanka and determined its antimicrobial resistance. METHODS: A total of 215 ExPEC isolates were collected from humans (n = 179) and dogs (n = 36) from two different cities in Sri Lanka. Antimicrobial resistance was tested by the disk diffusion method, and the presence of resistance-encoding genes (bla, blaand bla) and ST131 clades/subclades was tested by PCR. RESULTS: The majority of the isolates were (61.8%) ST131, with 55.8% in ST131-clade C. Of the clade C isolates, 44.3%, 27.8%, 15.7% and 6.7% were in clades C2, C other, C1-non-M27 and C1-M27, respectively. Approximately 11% of the ST131 isolates were carbapenem resistant. ExPEC from dogs showed comparable resistance rates to human isolates except for resistance to amoxicillin-clavulanate and amikacin. CONCLUSION: We observed a high occurrence of ST131 and its clade C, with more than 11% exhibiting resistance to carbapenems in Sri Lanka. Furthermore, ST131-C1-M27, with high resistance to both quinolones and extended-spectrum cephalosporins, was also present. Our results emphasise the importance of the One Health approach in the monitoring of antimicrobial-resistant E. coli in different regions of Sri Lanka to gain a better understanding of their prevalence over time, contributing to effective antimicrobial stewardship.