Phenotypic and genotypic characterizations of extended-spectrum beta-lactamase-producing in Thailand.

PURPOSE

Extended-spectrum β-lactamases (ESBLs) have become an issue in community worldwide due to an increase in antibiotic resistance over the past decade. This study was aimed to investigate the phenotypic and genotypic characteristics of ESBL-producing in Thailand.

MATERIALS AND METHODS

In this study, all clinical isolates collected from tertiary hospitals in Thailand were identified as by biochemical tests and MALDI-TOF mass spectrometry. ESBL-producing was preliminary screened with disk diffusion method by cephalosporin disks and confirmed by the method of combination disk diffusion. Antimicrobial susceptibility test was used to determine MIC values of all ESBL-producing . For genotypic detection, a variety of ESBL genes were determined by PCR. Moreover, multilocus sequence typing (MLST) analysis was performed on internal portions of seven housekeeping genes for the diversity and phylogenetic relatedness of clonal group.

RESULTS

Of the 285 ESBL-producing , most were susceptible to carbapenems. These strains showed a high resistance rate to ciprofloxacin (85.26%). The most frequently detected gene was group at about 71.23% followed by group (38.95%). The , , , , and genes were identified in 31.93%, 5.96%, 4.56%, 3.51%, and 0.70% of ESBL-producing isolates, respectively. The OXA-10 gene was detected in only one strain. ESBL-producing isolates with high antimicrobial resistance were further investigated. Among those, sequence type ST38 was mostly found, followed by ST405, ST410, and ST131. It is noteworthy that the gene was mainly detected in all four ST-type clones (ST38, ST405, ST410, and ST131).

CONCLUSION

This study provided a recent evidence of the genetic diversity of ESBL-producing in Thailand. In addition, the profile related to antimicrobial resistance pattern in this region was also demonstrated.