scholarly journals Cloning and Characterization of SmeT, a Repressor of the Stenotrophomonas maltophilia Multidrug Efflux Pump SmeDEF

2002 ◽  
Vol 46 (11) ◽  
pp. 3386-3393 ◽  
Author(s):  
Patricia Sánchez ◽  
Ana Alonso ◽  
Jose L. Martinez
Keyword(s):  
Stenotrophomonas Maltophilia ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
S1 Nuclease ◽  
Cellular Factor ◽  
S1 Nuclease Mapping ◽  
Nuclease Mapping

ABSTRACT We report on the cloning of the gene smeT, which encodes the transcriptional regulator of the Stenotrophomonas maltophilia efflux pump SmeDEF. SmeT belongs to the TetR and AcrR family of transcriptional regulators. The smeT gene is located upstream from the structural operon of the pump genes smeDEF and is divergently transcribed from those genes. Experiments with S. maltophilia and the heterologous host Escherichia coli have demonstrated that SmeT is a transcriptional repressor. S1 nuclease mapping has demonstrated that expression of smeT is driven by a single promoter lying close to the 5′ end of the gene and that expression of smeDEF is driven by an unique promoter that overlaps with promoter PsmeT. The level of expression of smeT is higher in smeDEF-overproducing S. maltophilia strain D457R, which suggests that SmeT represses its own expression. Band-shifting assays have shown that wild-type strain S. maltophilia D457 contains a cellular factor(s) capable of binding to the intergenic smeT-smeD region. That cellular factor(s) was absent from smeDEF-overproducing S. maltophilia strain D457R. The sequence of smeT from D457R showed a point mutation that led to a Leu166Gln change within the SmeT protein. This change allowed overexpression of both smeDEF and smeT in D457R. It was noteworthy that expression of wild-type SmeT did not fully complement the smeT mutation in D457R. This suggests that the wild-type protein is not dominant over the mutant SmeT.

scholarly journals SmeDEF Multidrug Efflux Pump Contributes to Intrinsic Multidrug Resistance in Stenotrophomonas maltophilia

2001 ◽  
Vol 45 (12) ◽  
pp. 3497-3503 ◽  
Author(s):  
Li Zhang ◽  
Xian-Zhi Li ◽  
Keith Poole
Keyword(s):  
Multidrug Resistance ◽  
Antimicrobial Resistance ◽  
Stenotrophomonas Maltophilia ◽  
Antimicrobial Agents ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Intrinsic Resistance ◽  
Multidrug Efflux Pump

ABSTRACT Stenotrophomonas maltophilia is an emerging nosocomial pathogen that displays high-level intrinsic resistance to a variety of structurally unrelated antimicrobial agents. Efflux mechanisms are known to contribute to acquired multidrug resistance in this organism, and indeed, one such multidrug efflux system, SmeDEF, was recently identified. Still, the importance of SmeDEF to intrinsic antibiotic resistance in S. maltophilia had not yet been determined. Reverse transcription-PCR confirmed expression of thesmeDEF genes in wild-type S. maltophilia, and deletion of smeE or smeF in wild-type strains rendered the mutants hypersusceptible to several antimicrobials, suggesting that SmeDEF contributes to intrinsic antimicrobial resistance in this organism. Expression of smeDEF was also enhanced in an in vitro-selected multidrug-resistant mutant, although deletion of smeF but not of smeE in these mutants compromised antimicrobial resistance. Apparently, hyperexpressed SmeF is capable of functioning with additional multidrug efflux components to promote multidrug resistance in S. maltophilia.

scholarly journals The Biocide Triclosan Selects Stenotrophomonas maltophilia Mutants That Overproduce the SmeDEF Multidrug Efflux Pump

2005 ◽  
Vol 49 (2) ◽  
pp. 781-782 ◽  
Author(s):  
Patricia Sanchez ◽  
Eduardo Moreno ◽  
Jose L. Martinez
Keyword(s):  
Type Strain ◽  
Stenotrophomonas Maltophilia ◽  
Wild Type Strain ◽  
Efflux Pump ◽  
Resistant Bacteria ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Antibiotic Resistant ◽  
Selection Of

ABSTRACT The possibility that triclosan selects Stenotrophomonas maltophilia mutants overexpressing the multidrug resistance pump SmeDEF is analyzed. Five out of 12 triclosan-selected mutants were less susceptible to antibiotics than the wild-type strain and overproduced SmeDEF. Results are discussed in relation to current debates on the potential selection of antibiotic-resistant bacteria by household biocides.

scholarly journals Gene Cloning and Characterization of VcrM, a Na+-Coupled Multidrug Efflux Pump, fromVibrio choleraeNon-O1

2003 ◽  
Vol 47 (6) ◽  
pp. 419-427 ◽  
Author(s):  
Md. Nazmul Huda ◽  
Jing Chen ◽  
Yuji Morita ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Gene Cloning ◽  
Efflux Pump ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Gene Cloning And Characterization

scholarly journals AcrAB Multidrug Efflux Pump Is Associated with Reduced Levels of Susceptibility to Tigecycline (GAR-936) in Proteus mirabilis

2003 ◽  
Vol 47 (2) ◽  
pp. 665-669 ◽  
Author(s):  
Melissa A. Visalli ◽  
Ellen Murphy ◽  
Steven J. Projan ◽  
Patricia A. Bradford
Keyword(s):  
Proteus Mirabilis ◽  
Efflux Pump ◽  
Wild Type ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Transposon Insertion ◽  
Spectrum Activity ◽  
Insertion Mutants ◽  
Broad Spectrum Activity ◽  
Increased Susceptibility

ABSTRACT Tigecycline has good broad-spectrum activity against many gram-positive and gram-negative pathogens with the notable exception of the Proteeae. A study was performed to identify the mechanism responsible for the reduced susceptibility to tigecycline in Proteus mirabilis. Two independent transposon insertion mutants of P. mirabilis that had 16-fold-increased susceptibility to tigecycline were mapped to the acrB gene homolog of the Escherichia coli AcrRAB efflux system. Wild-type levels of decreased susceptibility to tigecycline were restored to the insertion mutants by complementation with a clone containing a PCR-derived fragment from the parental wild-type acrRAB efflux gene cluster. The AcrAB transport system appears to be associated with the intrinsic reduced susceptibility to tigecycline in P. mirabilis.

Characterization of the Serratia marcescens SdeCDE multidrug efflux pump studied via gene knockout mutagenesis

2008 ◽  
Vol 54 (5) ◽  
pp. 411-416 ◽  
Author(s):  
Sanela Begic ◽  
Elizabeth A. Worobec
Keyword(s):  
Antibiotic Resistance ◽  
Substrate Specificity ◽  
Serratia Marcescens ◽  
Efflux Pump ◽  
Gene Knockout ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump ◽  
Active Efflux ◽  
Major Mechanism

Serratia marcescens is an important nosocomial agent having high antibiotic resistance. A major mechanism for S. marcescens antibiotic resistance is active efflux. To ascertain the substrate specificity of the S. marcescens SdeCDE efflux pump, we constructed pump gene deletion mutants. sdeCDE knockout strains showed no change in antibiotic susceptibility in comparison with the parental strains for any of the substrates, with the exception of novobiocin. In addition, novobiocin was the only antibiotic to be accumulated by sdeCDE-deficient strains. Based on the substrates used in our study, we conclude that SdeCDE is a Resistance–Nodulation–Cell Division family pump with limited substrate specificity.

scholarly journals Molecular Cloning and Characterization of the HmrM Multidrug Efflux Pump fromHaemophilus influenzaeRd

2003 ◽  
Vol 47 (12) ◽  
pp. 937-943 ◽  
Author(s):  
Xing-Jue Xu ◽  
Xian-Zhong Su ◽  
Yuji Morita ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Molecular Cloning ◽  
Efflux Pump ◽  
Multidrug Efflux ◽  
Multidrug Efflux Pump

scholarly journals Functional Cloning and Characterization of a Multidrug Efflux Pump, MexHI-OpmD, from a Pseudomonas aeruginosa Mutant

2003 ◽  
Vol 47 (9) ◽  
pp. 2990-2992 ◽  
Author(s):  
Hiroshi Sekiya ◽  
Takehiko Mima ◽  
Yuji Morita ◽  
Teruo Kuroda ◽  
Tohru Mizushima ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Ethidium Bromide ◽  
Rhodamine 6G ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Multidrug Efflux ◽  
Chromosomal Dna ◽  
Multidrug Efflux Pump ◽  
Multidrug Efflux Pumps

ABSTRACT We isolated mutant YM644, which showed elevated resistance to norfloxacin, ethidium bromide, acriflavine, and rhodamine 6G, from Pseudomonas aeruginosa YM64, a strain that lacks four major multidrug efflux pumps. The genes responsible for the resistance were mexHI-opmD. Elevated ethidium extrusion was observed with cells of YM644 and YM64 harboring a plasmid carrying the genes. Disruption of the genes in the chromosomal DNA of YM644 made the cells sensitive to the drugs.

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