Functional Gene Cloning and Characterization of the SsmE Multidrug Efflux Pump from Serratia marcescens

Abstract

We cloned a gene responsible for multidrug resistance from chromosomal DNA of Serratia marcescens, and determined the nucleotide sequence. We designated the gene as ssmE. The deduced amino acid sequence of SsmE showed high similarity with the small multidrug resistance (SMR)-type multidrug efflux pumps. Cells of Escherichia coli KAM32, a drug hyper-susceptible mutant, transformed with a plasmid pESM437 carrying the ssmE gene showed elevated minimum inhibitory concentrations of structurally unrelated antimicrobial agents. E. coli KAM32/pESM437 showed elevated energy dependent efflux of ethidium. Reverse transcriptase polymerase chain reaction (RT-PCR) analysis revealed that ssmE was expressed in cells of S. marcescens.

Role of AbeS, a Novel Efflux Pump of the SMR Family of Transporters, in Resistance to Antimicrobial Agents in Acinetobacter baumannii

“…Overall, results demonstrated that AbeS could decrease susceptibility to some antibiotics, disinfectants, dyes, and detergents. The broad substrate specificity displayed by AbeS was very similar to those of other SMR transporters reported previously (6,14,16,17,34).…”

“…Reports show that 52% of currently sequenced genomes of eubacteria and archaea contain at least one SMR homologue (2). Well-studied examples of SMR efflux pumps include EmrE of Pseudomonas aeruginosa, EbrAB of Bacillus subtilis, SsmE of Serratia marcescens, and EmrE of Escherichia coli, which are involved in resistance to a variety of antimicrobial agents and quaternary ammonium compounds (14,16,17,34).…”

Transforming a drug/H + antiporter into a polyamine importer by a single mutation

“…fluoroquinolones (9). The amino acid at the equivalent position in SsmE is leucine as in wild-type EmrE.…”

SugE, a New Member of the SMR Family of Transporters, Contributes to Antimicrobial Resistance in Enterobacter cloacae

“…The expression level of sugE in DFW9 was similar to that seen with ATCC 13047. In order to establish that SugE has the ability to extrude drugs from bacterial cells, we observed the efflux of ethidium from within preloaded cells by using a method described previously (14,15). KAM32/pSTV28 (control) and KAM32/ pSUGE28 cells carrying the sugE gene were tested.…”