Open AccessDetection of an IS21 insertion sequence in the mexR gene of Pseudomonas aeruginosa increasing β‐lactam resistance
Author(s) -
Boutoille David,
Corvec Stéphane,
Caroff Nathalie,
Giraudeau Cécile,
Espaze Eric,
Caillon Jocelyne,
Plésiat Patrick,
Reynaud Alain
Publication year - 2004
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 - 10.1016/s0378-1097(03)00882-6
Subject(s) - pseudomonas aeruginosa , biology , insertion sequence , ticarcillin , efflux , gene , genetics , sequence analysis , microbiology and biotechnology , transposable element , piperacillin , mutant , bacteria
To understand the regulation of the MexAB OprM efflux system in a clinical strain of Pseudomonas aeruginosa presenting a decreased susceptibility to ticarcillin and aztreonam, the mexR repressor gene was amplified by polymerase chain reaction (PCR) and was shown to be disrupted by an insertion sequence of more than 2 kb, with characteristic direct and inverted repeat sequences. Sequencing revealed a 2131‐bp IS21 insertion sequence. A reverse transcription PCR method was used to quantify mexA transcripts and showed an increased transcription rate of mexA in this strain, compared with a PAO1 control strain. The nalB phenotype in P. aeruginosa may be due to point mutations, but also to the presence of an insertion sequence in the mexR regulator gene.