Prevalence of hypermutator isolates of Achromobacter spp. from cystic fibrosis patients.

Prevalence of hypermutator isolates of Achromobacter spp. from cystic fibrosis patients. Int J Med Microbiol. 2020 Jan 16;:151393 Authors: Ridderberg W, Jensen Handberg K, Nørskov-Lauritsen N Abstract Bacteria colonising the lungs of cystic fibrosis (CF) patients encounter high selective pressures. Hypermutation facilitates adaptation to fluctuating environments, and hypermutator strains are frequently isolated from CF patients. We investigated the prevalence of hypermutator isolates of Achromobacter spp. among patients affiliated with the CF Centre in Aarhus, Denmark. By exposure to rifampicin, the mutation frequency was determined for 90 isolates of Achromobacter spp. cultured from 42 CF patients; 20 infections were categorised as chronic, 22 as intermittent. The genetic mechanisms of hypermutation were examined by comparing DNA repair gene sequences from hypermutator and normomutator isolates. Achromobacter spp. cultured from 11 patients were categorised as hypermutators, and this phenotype was exclusively associated with chronic infections. Isolates of the Danish epidemic strain (DES) of Achromobacter ruhlandii cultured from patients from both Danish CF centres showed elevated mutation frequencies. The hypermutator state of Achromobacter spp. was most commonly associated with nonsynonymous mutations in the DNA mismatch repair gene mutS; a single clone had developed a substitution in the S-adenosyl-L-methionine-dependent methyltr...
Source: International Journal of Medical Microbiology - Category: Microbiology Authors: Tags: Int J Med Microbiol Source Type: research