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High‐Level Fluoroquinolone Resistance in Pseudomonas aeruginosa Due to Interplay of the MexAB‐OprM Efflux Pump and the DNA Gyrase Mutation
Author(s) -
Nakajima Akira,
Sugimoto Yohko,
Yoneyama Hiroshi,
Nakae Taiji
Publication year - 2002
Publication title -
microbiology and immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 70
eISSN - 1348-0421
pISSN - 0385-5600
DOI - 10.1111/j.1348-0421.2002.tb02711.x
Subject(s) - efflux , dna gyrase , pseudomonas aeruginosa , biology , mutation , microbiology and biotechnology , mutant , topoisomerase iv , operon , genetics , escherichia coli , bacteria , gene
Fluoroquinolone resistance in Pseudomonas aeruginosa is mainly attributable to the constitutive expression of the xenobiotic efflux pump and mutation in DNA gyrase or topoisomerase IV. We constructed cells with a double‐mutation in gyrA and mexR encoding DNA gyrase and repressor for the mexAB‐oprM operon, respectively. The mutant showed 1,024 times higher fluoroquinolone resistance than cells lacking the MexAB‐OprM. Cells with a single mutation in gyrA and producing a wild‐type level of the MexAB‐OprM efflux pump showed 128 times higher fluoroquinolone resistance than cells lacking the MexAB‐OprM. In contrast, a single mutation in gyrA or mexR caused only 4 and 64 times higher resistance, respectively. These findings manifested the interplay between the MexAB‐OprM efflux pump and the target mutation in fluoroquinolone resistance.