BACKGROUND

The antimicrobial resistance of extraintestinal pathogenic (ExPEC) has progressively been reported worldwide. This resistance has been ascribed to global dissemination of a single clone, namely sequence type 131 ( ST131). The main goal of this study is to determine the prevalence and molecular traits of ST131 and its subclones among clinical urine isolates in Riyadh, Saudi Arabia.

METHODS

Sixty urine isolates, of different extended spectrum β-lactamase (ESBL) carriage, were involved in this study. Molecular characterization was carried out to determine the ST131 status, phylogenetic groups and virulence carriage of these isolates. ST131 isolates were further tested to evaluate the prevalence of different phylogenetic groups, subclones and virulence carriage.

RESULTS

Group B2 was the most common phylogroup from which isolates derived. Overall, 37 of 60 (61.7%) isolates belonged to ST131 clones. Of these, 19 (31.7%) isolates were from the subclone, including 10 (16.7%) non-Rx and 9 (15%) Rx. The remaining 18 (30%) ST131 isolates belonged to other non subclones. subclone was significantly higher in the virulence carriage in comparison to non ST131 subclones.

CONCLUSION

This study reported the prevalence and traits of clinical ST131 main subclones in Saudi Arabia. It also demonstrated the high prevalence of ST131 locally, and found different virulence genotypes and antimicrobial resistance phenotypes among ST131 subclones. In the future, preforming whole genome sequence-based studies on ST131 and its subclones is crucial to elucidate factors that drive the success of these organisms.