Dear Editor, RND (resistance nodulation-cell division) exporters are widely expressed across the lineage of Gram-negative bacteria (Fig. S1 ). Their functional role is to utilize the protonmotive force of the cell to ...Dear Editor, RND (resistance nodulation-cell division) exporters are widely expressed across the lineage of Gram-negative bacteria (Fig. S1 ). Their functional role is to utilize the protonmotive force of the cell to drive the expulsion of cytotoxic substances from the outer leaflet of the inner membrane as well as the periplasm to extracellular space (Yamaguchi et al., 2015).展开更多
Benzalkonium chloride(BAC) is an effective disinfectant against Salmonella and widely used in the food industry.However,there are growing concerns about the risk of inducing Salmonella to produce crossresistance to an...Benzalkonium chloride(BAC) is an effective disinfectant against Salmonella and widely used in the food industry.However,there are growing concerns about the risk of inducing Salmonella to produce crossresistance to antibiotics resulting from the excessive use of BAC.In this study,50 foodborne Salmonella isolates were exposed to sub-inhibitory concentrations of BAC.It was demonstrated that 7 isolates showed direct resistance to BAC,and 35 isolates showed cross-resistance to at least one of 10 tested antibiotics.Among these 35 isolates,15 isolates exhibited an increase in minimum inhibitory concentration(MIC) for tetracycline,followed by 11 isolates for kanamycin and 9 isolates for ampicillin.Salmonella Enteritidis SJTUSM06 with the highest increase in MIC of tetracycline(from 4 to 32 μg/mL) was selected for further study.Tandem mass tag-labeled proteomics was used to determine key proteins involved in development of cross-resistance to tetracycline in BAC-adapted S.Enteritidis.It was identified that there were 146 differentially expressed proteins,including 95 up-regulated and 51 down-regulated proteins,most of which were involved in carbohydrate and lipid metabolism,ribosomes,transporters,virulence,motility,and stress response pathways.The efflux pump AcrB was significantly upregulated by 2.03-fold in BAC-adapted S.Enteritidis.It was also demonstrated that efflux pump inhibitor phenylalanine-arginine β-naphthylamide(PaβN) decreased the MIC of tetracycline in BAC-adapted S.Enteritidis from 32 to 8 μg/mL,indicating that active efflux pump played an important role in the development of resistance to tetracycline induced by BAC.Deletion of acrB resulted in a decrease in the resistance to tetracycline in BAC-adapted S.Enteritidis.Compared with the parent strain,MIC for tetracycline in ΔacrB mutant was 16 μg/mL with a 2-fold decrease.These results demonstrated that AcrB played a positive role in the development of crossresistance to tetracycline after adaptation of S.Enteritidis to BAC.展开更多
基金The authors thank Dr. Yong Tao of the Institute of Microbiology, CAS, for providing the ΔacrB cell strain. We thank Dr. Torsten Juelich for linguistic assistance during the preparation of this manuscript. supported by the National Basic Research Program (973 Program) (No. 2015CB910104 to XCZ)National Natural Science Foundation of China (Grant No. 31470745 to XCZ).
文摘Dear Editor, RND (resistance nodulation-cell division) exporters are widely expressed across the lineage of Gram-negative bacteria (Fig. S1 ). Their functional role is to utilize the protonmotive force of the cell to drive the expulsion of cytotoxic substances from the outer leaflet of the inner membrane as well as the periplasm to extracellular space (Yamaguchi et al., 2015).
基金supported by the National Natural Science Foundation of China(32172316)。
文摘Benzalkonium chloride(BAC) is an effective disinfectant against Salmonella and widely used in the food industry.However,there are growing concerns about the risk of inducing Salmonella to produce crossresistance to antibiotics resulting from the excessive use of BAC.In this study,50 foodborne Salmonella isolates were exposed to sub-inhibitory concentrations of BAC.It was demonstrated that 7 isolates showed direct resistance to BAC,and 35 isolates showed cross-resistance to at least one of 10 tested antibiotics.Among these 35 isolates,15 isolates exhibited an increase in minimum inhibitory concentration(MIC) for tetracycline,followed by 11 isolates for kanamycin and 9 isolates for ampicillin.Salmonella Enteritidis SJTUSM06 with the highest increase in MIC of tetracycline(from 4 to 32 μg/mL) was selected for further study.Tandem mass tag-labeled proteomics was used to determine key proteins involved in development of cross-resistance to tetracycline in BAC-adapted S.Enteritidis.It was identified that there were 146 differentially expressed proteins,including 95 up-regulated and 51 down-regulated proteins,most of which were involved in carbohydrate and lipid metabolism,ribosomes,transporters,virulence,motility,and stress response pathways.The efflux pump AcrB was significantly upregulated by 2.03-fold in BAC-adapted S.Enteritidis.It was also demonstrated that efflux pump inhibitor phenylalanine-arginine β-naphthylamide(PaβN) decreased the MIC of tetracycline in BAC-adapted S.Enteritidis from 32 to 8 μg/mL,indicating that active efflux pump played an important role in the development of resistance to tetracycline induced by BAC.Deletion of acrB resulted in a decrease in the resistance to tetracycline in BAC-adapted S.Enteritidis.Compared with the parent strain,MIC for tetracycline in ΔacrB mutant was 16 μg/mL with a 2-fold decrease.These results demonstrated that AcrB played a positive role in the development of crossresistance to tetracycline after adaptation of S.Enteritidis to BAC.
