Role of ampD homologs in overproduction of AmpC in clinical isolates of Pseudomonas aeruginosa.

ABSTRACT: AmpD indirectly regulates the production of AmpC beta-lactamase via the cell wall recycling pathway. Recent publications have demonstrated the presence of multiple ampD genes in Pseudomonas aeruginosa and Escherichia coli. In the prototype P. aeruginosa strain, PAO1, the three ampD genes (ampD, ampDh2, and ampDh3) contribute to a stepwise regulation of ampC beta-lactamase and help explain the partial versus full derepression of ampC. In the present study, the roles of the three ampD homologs in nine clinical P. aeruginosa isolates with either partial or full derepression of ampC were evaluated. In eight of nine isolates, decreased RNA expression of the ampD genes was not associated with an increase in ampC expression. Sequence analyses revealed that every derepressed isolate carried mutati

SUBMITTER: Schmidtke AJ 

PROVIDER: S-EPMC2573135 | biostudies-literature | 2008 Nov

REPOSITORIES: biostudies-literature