Abstract

This study investigated the simulated solar light disinfection of Escherichia coli CGMCC 1.1595, a multidrug resistant (MDR) strain resistant to tetracycline and ampicillin. With the increased of light intensity, the maximum inactivation efficiency reached 0.74 log in 60 min following visible light irradiation with an intensity of 115.8 mW/cm2 and following UVA – visible light irradiation, using a 98% UVA ray contribution at 6.5 mW/cm2 and 95% contribution at 20.0 mW/cm2, the inactivation efficiency was up to 6.09 log. The inactivated MDR E. coli did not regrow after light irradiation or in dark after 24 or 48 h after visible light disinfection, demonstrating that visible light disinfection can prevent the MDR E. coli self repair. The MDR E. coli plasmid electrophoresis band gradually went dark with increasing of the light irradiation time and could be completely eliminated by high UVA light intensity treatment, however, simulated sunlight irradiation had minimal influence on both tetracycline and ampicillin resistance of the MDR E. coli strain.

HIGHLIGHTS

  • The simulated solar light can inactivate multidrug resistant (MDR) Escherichia coli CGMCC 1.1595.

  • The inactivation efficiency of MDR E. coli reached 0.74 log in 60 min under visible light irradiation.

  • The inactivation efficiency of MDR E. coli was up to 6.09 log under UVA-visible light irradiation.

  • The visible light disinfection can prevent the MDR E. coli self repair.

  • Simulated sunlight irradiation had minimal impact on the tetracycline and ampicillin resistance of the MDR E. coli.

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Supplementary data