Overexpression of target enzyme gene fabI and efflux pump decrease triclosan susceptibility in Escherichia coli

Abstract

Background: Escherichia coli isolates, the most opportunistic pathogen in the gut, are responsible for the most acquired infections. Triclosan is an effective disinfectant for inhibits microorganisms, but its widespread use causes its residue in urine, resulting in long-term exposure of E. coli in the intestine to triclosan environment and increasing triclosan resistance. We aim to provide the mechanism of action of E. coli isolates against triclosan and the molecular epidemiological analysis of triclosan-resistant strains.Results: Five triclosan-resistant isolates were screened out from 200 E. coli isolates by agar dilution method by to further study, interestingly, multidrug-resistant and cross-resistance phenotypes were observed in triclosan-resistant strains, but not in susceptible strains, and all except one exhibited an inhibition of efflux pump activity by efflux pump inhibition testing. Furthermore, compared with susceptible E. coli strain ATCC 25922, except fabI, increased expression were also found in efflux pump encoding genes ydcV, ydcU, ydcS, ydcT, cysP, yihV, acrB, acrD and mdfA in studied strains which had different PFGE patterns and STs types.Conclusions: These findings indicated that triclosan resistance in E. coli were mainly involved by overexpression of fabI gene, and there was a close association between overexpression of efflux pump with reducing susceptibility to triclosan. Besides, we described cross-resistance between triclosan and antibiotics may be related to the exposure time of triclosan.

Tolerancia al triclosán en cepas de Klebsiella pneumoniae y Escherichia coli de origen clínico

“…Asimismo, se ha informado que la resistencia a este biocida está influida por la sobreexpresión de genes y por la bomba de eflujo presente en bacterias, lo que contribuye a la reducción de la susceptibilidad al triclosán (27,34). Por ello, previos estudios moleculares de resistencia a antimicrobianos en los aislamientos seleccionados para el presente estudio mostraron una prevalencia de genes de resistencia en un 91,7 % de las muestras evaluadas, de las cuales blaTEM fue el más frecuente en los aislamientos, seguido por blaSHV y blaCTXM1 (22) (tabla 2).…”