Résumé
Objectives: The aim of this study was to assess the frequency and diversity of extended-spectrum beta-lactamases (ESBLs) produced by exclusively community-acquired Escherichia coli isolates in Izmir (Turkey) and to search for isolates producing CTX-M-15 and belonging to the pandemic clone E. coli O25-ST131.
Methods: The patients with E. coli urinary tract infections (UTIs) and no hospitalization in the last 12 months, and no transfer from hospital, no stay in nursing home and no antimicrobial treatment in the previous 3 months were prospectively included over a 1 year period. Those E. coli detected positive for ESBL were characterized and compared with a representative of E. coli clone O25-ST131 with regard to bla genes, antibiotic resistance, phylogenetic groups, PFGE profiles and virulence factor genes (n = 17). O serotyping, multilocus sequence typing (MLST) and AmpC typing were performed to confirm that the Turkish isolate belonged to the clone O25-ST131.
Results: Among the 3108 UTIs diagnosed, 82 (2.6%) were due to community E. coli isolates and followed the strict inclusion criteria. Seventeen of them (21%) produced an ESBL, of which CTX-M-15 was predominant (53%). These ESBL-positive isolates, distributed equally into three phylogenetic groups, displayed 13 PFGE profiles and three clusters. A Turkish CTX-M-15-producing isolate as a member of the clone ST131 was suggested by a high similarity of its PFGE profile to that of the clone representative and was confirmed by O serotyping, AmpC typing and MLST.
Conclusions: This study describes the community emergence of CTX-M-15-producing E. coli isolates, including an isolate of clone O25-ST131, in Turkey.