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In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa
13:40

In vitro Investigation of the MexAB Efflux Pump From Pseudomonas aeruginosa

Published on: February 17, 2014

mvaT mutation modifies the expression of the Pseudomonas aeruginosa multidrug efflux operon mexEF-oprN

Landon W Westfall1, Nancy L Carty, Nancy Layland

  • 1Department of Microbiology and Immunology, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA.

FEMS Microbiology Letters
|February 2, 2006
PubMed

Insights

The mvaT mutation in Pseudomonas aeruginosa increases resistance to certain antibiotics by upregulating the mexEF-oprN efflux operon. This study investigates the mechanisms behind this altered antibiotic resistance profile.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Genetics

Background:

  • Pseudomonas aeruginosa possesses multidrug efflux operons, such as mexEF-oprN, contributing to antibiotic resistance.
  • The mvaT gene influences the expression of various P. aeruginosa genes, impacting bacterial physiology.

Purpose of the Study:

  • To investigate the role of the mvaT gene in modulating the expression of multidrug resistance (MDR) operons in P. aeruginosa.
  • To determine the effect of mvaT mutation on the expression of mexEF-oprN and oprD genes and the resulting antibiotic susceptibility profile.

Main Methods:

  • Comparative analysis of antibiotic resistance in P. aeruginosa PAO1 and its mvaT mutant (PAODeltamvaT).
  • Quantitative assessment of mexEF-oprN and oprD gene expression using molecular techniques.
  • Investigation of the regulatory pathways (mexT, mexS) affected by mvaT mutation.

Main Results:

  • The mvaT mutant exhibited increased resistance to chloramphenicol and norfloxacin, and increased sensitivity to imipenem compared to the parent strain.
  • Expression of mexEF-oprN was significantly upregulated (five- to sixfold) in the mvaT mutant, while oprD expression was downregulated (twofold).
  • mvaT mutation did not influence mexEF-oprN expression via mexT or mexS and did not affect other MDR operons but increased ABC transporter gene expression.

Conclusions:

  • The mvaT gene plays a significant role in regulating mexEF-oprN expression and influencing the antibiotic susceptibility of P. aeruginosa.
  • The observed changes in efflux pump and transporter gene expression contribute to the altered MDR phenotype in the mvaT mutant.

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