Complementation of methionine auxotrophs of Pseudomonas aeruginosa from cystic fibrosis.
Barth AL. Woodford N. Pitt TL.
Laboratory of Hospital Infection, Central Public Health Laboratory, 61 Colindale Ave, London NW9 5HT, UK.
Auxotrophic Pseudomonas aeruginosa are exclusive to respiratory infections in cystic fibrosis (CF) and bronchiectatic patients, and isolates require specific amino acids for growth on minimal media, particularly methionine. Since auxotrophic and prototrophic P. aeruginosa from CF are identical by genotyping, we investigated the genetic events leading to methionine auxotrophy (Met-). Most (10/13) Met- strains had the same pattern of growth on methionine precursors and required methionine exclusively for growth. Back mutation to prototrophy was very low (frequencies 10(-8) to