Sub-lethal photocatalysis bactericidal technology cause longer persistence of antibiotic-resistance mutant and plasmid through the mechanism of reduced fitness cost

Abstract

Antibiotic-resistance bacteria (ARB) sustain longevity in environments representing a public health threat recently, but some current bactericidal technologies could eliminate ARB at endpoint of treatment. However, the intermediate process, where bacterial community might be shaped by a complex array of external stressor, was less to be investigated. Herein, the sub-lethal photocatalysis (Sub-PC) bactericidal technology was first applied to validate its effects on the fitness cost and fate of ARB mediated by mutations and antibiotic-resistance gene (ARG) encoded plasmid. Results revealed that the fitness cost of both two types of ARB decreased under Sub-PC conditions as compared with Luria-Broth (LB) broth condition. Plate counting revealed that antibiotic resistance mutant exhibited 6–7 days longer maintenance under the Sub-PC conditions than that under the LB condition. Besides, for plasmid-encoded ARB, the average abundance of ARG in bacteria community was maintained at 0.38 copies for ctx-1 and 0.58 copies for mcr-1 under the Sub-PC condition, which were higher than that under the LB condition (0.29 copies for ctx-1 and 0.45 copies for mcr-1). This study suggests that Sub-PC could cause longer-term maintenance of antibiotic resistance and provides an insightful understanding that how anthropogenic sterilization technologies or stressor may alleviate or spread bacterial antibiotic resistance.