title: RpoE is a Putative Antibiotic Resistance Regulator of Salmonella enteric Serovar Typhi.
abstract: Bacterial antimicrobial resistance has been associated with the up regulation of genes encoding efflux pumps and the down regulation of genes encoding outer membrane proteins (OMPs). Gene expression in bacteria is primarily initiated by sigma factors (σ factors) such as RpoE, which plays an important role in responding to many environmental stresses. Here, we report the first observation that RpoE serves as an antibiotic resistance regulator in Salmonella enteric serovar Typhi (S. Typhi). In this study, we found that the rpoE mutant (ΔrpoE) of S. Typhi GIFU10007 has elevated resistance to several antimicrobial agents, including β-lactams, quinolones, and aminoglycosides. Genomic DNA microarray analysis was used to investigate the differential gene expression profiles between a wild type and rpoE mutant in response to ampicillin. The results showed that a total of 57 genes displayed differential expression (two-fold increase or decrease) in ΔrpoE versus the wild-type strain. The expressions of two outer membrane protein genes, ompF and ompC, were significantly down-regulated in ΔrpoE (six and seven-fold lower in comparison to wild-type strain) and RamA, a member of the efflux pump AraC/XylS family, was up-regulated about four-fold in the ΔrpoE. Our results suggest RpoE is a potential antimicrobial regulator in S. Typhi, controlling both the down regulation of the OMP genes and up-regulating the efflux system.
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Xiaofang
authors.initials: X
authors.lastname: Xie
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Haifang
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Aiqing
authors.initials: A
authors.lastname: Li
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Min
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Huiqin
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China.
authors.forename: Xueming
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
authors.forename: Zachary
authors.initials: Z
authors.lastname: Schneider
authors.affiliation: Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.affiliation: Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA.
authors.forename: Barry N
authors.initials: BN
authors.lastname: Kreiswirth
authors.affiliation: Department of Clinical Laboratory, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, Jiangsu, People's Republic of China. hong_du@126.com.
authors.forename: Hong
authors.initials: H
authors.lastname: Du
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024881:Drug Resistance, Bacterial; D015870:Gene Expression; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D008826:Microbial Sensitivity Tests; D009154:Mutation; D060888:Real-Time Polymerase Chain Reaction; D015203:Reproducibility of Results; D012485:Salmonella typhi / Q000145:classification / Q000187:drug effects* / Q000235:genetics*; D012808:Sigma Factor / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D012808:Sigma Factor; C063202:sporulation-specific sigma factors; D000667:Ampicillin