title: Altered denA and anr gene expression in aminoglycoside adaptive resistance in Pseudomonas aeruginosa.
abstract: Adaptive resistance to aminoglycoside killing and cytoplasmic accumulation occurs in cultures of originally susceptible Pseudomonas aeruginosa following an initial incubation with aminoglycoside. Anaerobiosis has also been reported to reduce bacterial killing and limit cytoplasmic aminoglycoside accumulation. We hypothesized that a common mechanism may facilitate reduced bacterial killing and aminoglycoside accumulation in both cases. Northern blot analysis of P. aeruginosa adaptively resistant to gentamicin demonstrated increased mRNA levels of both denA (nitrite reductase), which facilitates terminal electron acceptance in the anaerobic respiratory pathway, and its regulatory protein, ANR, in the absence of promoter DNA sequence changes, when compared with controls. These observations suggested that P. aeruginosa may regulate the expression of genes in its anaerobic respiratory pathway in response to aminoglycosides and may explain, at least partially, P. aeruginosa adaptive resistance to aminoglycosides.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: J A
authors.initials: JA
authors.lastname: Karlowsky
authors.forename: D J
authors.initials: DJ
authors.lastname: Hoban
authors.forename: S A
authors.initials: SA
authors.lastname: Zelenitsky
authors.forename: G G
authors.initials: GG
authors.lastname: Zhanel
mesh_terms: D000617:Aminoglycosides; D000693:Anaerobiosis; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015152:Blotting, Northern; D015342:DNA Probes; D004352:Drug Resistance, Microbial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D012329:RNA, Bacterial / Q000378:metabolism; D017422:Sequence Analysis, DNA
chemical_list: D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D015342:DNA Probes; D012329:RNA, Bacterial