nfxB as a Novel Target for Analysis of Mutation Spectra in Pseudomonas aeruginosa

MONTI MR; MORERO NR; MIGUEL V; ARGARAÑA CE

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2013 vol. 8 p. 1 - 1

fxB encodes a negative regulator of the mexCD-oprJ genes for drug efflux in the opportunistic pathogen Pseudomonas aeruginosa. Inactivating mutations in this transcriptional regulator constitute one of the main mechanisms of resistance to ciprofloxacin (Cipr). In this work, we evaluated the use of nfxB/Cipr as a new test system to study mutation spectra in P. aeruginosa. The analysis of 240 mutations in nfxB occurring spontaneously in the wild-type and mutator backgrounds or induced by mutagens showed that nfxB/Cipr offers several advantages compared with other mutation detection systems. Identification of nfxB mutations was easy since the entire open reading frame and its promoter region were sequenced from the chromosome using a single primer. Mutations detected in nfxB included all transitions and transversions, 1-bp deletions and insertions, .1-bp deletions and duplications. The broad mutation spectrum observed in nfxB relies on the selection of loss-of-function changes, as we con