MOLECULAR EPIDEMIOLOGY OF CTX-M-15 EXTENDED-SPECTRUM Β-LACTAMASE-PRODUCING Escherichia coli IN THE COMMUNITY

In recent years, the prevalence of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolated from the sites of urinary tract infections has seen an increase not only in the hospital but also in the community worldwide. Among the various ESBLs produced by E. coli, the CTX-M family currently predominates and substitutes the classic SHV and TEM types. There are more than 170 different types of CTX-M β-lactamases that can be divided into 5 groups: CTX-M-1, -2, -8, -9, and -25. CTX-M-1 group contains 6 enzymes dependent on plasmid: CTX-M-1, CTX-M-3, CTX-M-10, CTX-M-12, CTX-M-15 and, FEC-4. Within this family, CTX-M-15 has become the most widely distributed in the world. Furthermore, E. coli strains producing CTX-M-15, which are generally multidrug resistant have emerged as an important pathogen. However, knowledge about the epidemiology of these infections in the community is still limited. The objectives of this work were to characterize the ESBL from Enterobacteriaceae isolated from urocultures and investigated the frequency of E. coli encoding genes for CTX-M-15. Cultures of patients of the basic units of health and ready care of Londrina, in period from June 2016 to May 2017, were performed by the Central Laboratory of the City of Londrina – Paraná. The ESBLs were characterized by multiplex PCR. In the studied period, 8.382 uropathogens were detected by the Vitek2@ automated system (bioMérieux), being that 489 (6,7%) were ESBL producers. In this period, 5,761 (69,8%) E. coli isolates were identified, which of 329 (5,7%) were ESBL producers and 688 K. pneumoniae isolates, that 159 (24,2%) were ESBL producers. Of the 329 E. coli samples, 302 (92,5%) harboured the blaCTX-M gene, individually or in associations. The frequency of bla genotypes ESBL showed that blaTEM, alone and/or double groups, were detect to harbor in 24,6% (81/329) ESBL producing E.coli and 36,4% (58/159) ESBL producing K. pneumoniae, blaSHV in 28,5% (94/329) and 23,2% (37/159) isolates, respectively. The blaCTX-M in 83,5% (275/329) and 83,0% (132/159) ESBL producing isolates in E. coli and K. pneumoniae, respectively. blaCTX-M-1 positive groups were detected at 54,4% (179/329) ESBL producing E. coli and 56,6% (90/159) ESBL producing K. pneumoniae, alone and/or double bla groups. The blaCTX-M15 gene was found predominantly in ESBL-producing E. coli (n=113/179; 63,1%). This study described high prevalence of CTX-M-15 ESBL type among E. coli isolates in urinary tract infections in the community. The apparent dissemination of CTX-M producers could represent a substantial barrier in the treatment of community-acquired infections.