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Role of the MexXY multidrug efflux pump in moderate aminoglycoside resistance in Pseudomonas aeruginosa isolates from Pseudomonas mastitis
Author(s) -
Chuanchuen Rungtip,
Wannaprasat Wechsiri,
Ajariyakhajorn Kittisak,
Schweizer Herbert P.
Publication year - 2008
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.1348-0421.2008.00051.x
Subject(s) - efflux , aminoglycoside , pseudomonas aeruginosa , biology , microbiology and biotechnology , multiple drug resistance , pseudomonadaceae , pseudomonadales , antibiotics , bacteria , genetics
The contribution of the MexXY multidrug efflux system to aminoglycoside resistance was investigated in 18 clinical isolates of Pseudomonas aeruginosa obtained from dairy cows with Pseudomonas mastitis. All of the isolates expressed MexXY as determined by reverse transcription‐PCR. The loss of mexXY resulted in increased susceptibility (two‐ to 16‐fold decline in MIC) to aminoglycosides, confirming the contribution of this system in aminoglycoside resistance in these strains. As the impact of Δ mexXY varied, overexpression of MexXY alone is not sufficient for aminoglycoside resistance. Expression of mexXY also varied and did not strictly correlate with aminoglycoside insusceptibility. Transcription levels of mexY were independent on mutations in mexZ , suggesting the existence of additional regulatory mechanisms other than mexZ .