title: Expression of the marA, soxS, acrB and ramA genes related to the AcrAB/TolC efflux pump in Salmonella enterica strains with and without quinolone resistance-determining regions gyrA gene mutations.
abstract: Several studies have been conducted in recent years to elucidate the structure, function and significance of AcrB, MarA, SoxS and RamA in Salmonella enterica. In this study, the relative quantification of acrB, soxS, marA and ramA genes expression was evaluated in 14 strains of S. enterica, with or without accompanying mutations in the quinolone resistance-determining regions of the gyrA gene, that were exposed to ciprofloxacin during the exponential growth phase. The presence of ciprofloxacin during the log phase of bacterial growth activated the genes marA, soxS, ramA and acrB in all S. enterica strains analyzed in this study. The highest expression levels for acrB were observed in strains with gyrA mutation, and marA showed the highest expression in the strains without mutation. Considering only the strains with ciprofloxacin minimum inhibitory concentration values<0.125 μg/mL (sensitive to ciprofloxacin), the most expressed gene in the strains both with and without mutations was acrB. In the strains with ciprofloxacin minimum inhibitory concentration values ≥ 0.125 μg/mL (low susceptibility), with and without mutations in gyrA, the most expressed gene was marA. In this study, we observed that strains resistant to nalidixic acid may express genes associated with the efflux pump and the expression of the AcrAB-TolC pump genes seems to occur independently of mutations in gyrA.
authors: Agricultural Sciences Center, Department of Food Science and Technology, Universidade Estadual de Londrina, Londrina, PR, Brazil. rafaelaferrari@yahoo.com.br
authors: Rafaela Gomes
authors: RG
authors: Ferrari
authors: Antonio
authors: A
authors: Galiana
authors: Rosa
authors: R
authors: Cremades
authors: Juan Carlos
authors: JC
authors: Rodríguez
authors: Marciane
authors: M
authors: Magnani
authors: Maria Cristina Bronharo
authors: MC
authors: Tognim
authors: Tereza C R M
authors: TC
authors: Oliveira
authors: Gloria
authors: G
authors: Royo
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D002939:Ciprofloxacin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial / Q000235:genetics; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D009154:Mutation / Q000235:genetics*; D012329:RNA, Bacterial / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019779:Salmonella enterica / Q000187:drug effects* / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
chemical_list: C474926:AcrB protein, Salmonella enterica; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; C485380:MarA protein, Salmonella enterica; D026901:Membrane Transport Proteins; D012329:RNA, Bacterial; C579436:RamA protein, Salmonella enterica; C485381:SoxS protein, Salmonella enterica; D015534:Trans-Activators; D002939:Ciprofloxacin