Open AccessmvaT mutation modifies the expression of the Pseudomonas aeruginosa multidrug efflux operon mexEF ‐ oprN
Author(s) -
Westfall Landon W.,
Carty Nancy L.,
Layland Nancy,
Kuan Phillip,
ColmerHamood Jane A.,
Hamood Abdul N.
Publication year - 2006
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.2005.00075.x
Subject(s) - efflux , operon , pseudomonas aeruginosa , mutant , biology , microbiology and biotechnology , multiple drug resistance , norfloxacin , genetics , imipenem , mutation , gene , drug resistance , antibiotics , bacteria , ciprofloxacin
Pseudomonas aeruginosa carries several multidrug efflux operons, including mexEF‐oprN , that contribute to its resistance to multiple antibiotics. mvaT affects the expression of several P. aeruginosa genes. In this study, we show that the mvaT mutant PAOΔ mvaT is more resistant than its parent PAO1 strain to chloramphenicol and norfloxacin but more sensitive to imipenem; yet both were less resistant to chloramphenicol, norfloxacin, and imipenem than ‘typical’ nfxC ‐type mutants. Neither strain carries the deletion described for nfxC ‐type mutants in mexT , the mexEF‐oprN regulatory gene. Expression of mexEF‐oprN is increased by five‐ to sixfold in PAOΔ mvaT , while the expression of oprD is reduced by approximately twofold. mvaT mutation had no effect on the expression of other multidrug resistance operons, although it increased the expression of several ATP‐binding cassette transporter genes. We show that mvaT mutation does not affect mexEF‐oprN expression through mexT or mexS . We also explored several other potential mechanisms.