Frontiers in cellular and infection microbiology
Genomic characterization of a mobile-element-associated resistance island in trimethoprim-sulfamethoxazole-resistant Stenotrophomonas maltophilia isolates sharing the same PFGE genotype
By Altan G, Rakıcı E, Dündar D and 1 others.
Abstract
Background
Stenotrophomonas maltophilia is an opportunistic nosocomial pathogen with intrinsic multidrug resistance and limited therapeutic options. This study integrated phenotypic susceptibility testing, targeted molecular screening, PFGE and short-read whole-genome sequencing (WGS) to characterize resistance determinants and their local genomic context in clinical-culture isolates.
Methods
Thirty-four non-duplicate clinical-culture isolates were analyzed. Susceptibility to trimethoprim-sulfamethoxazole (TMP-SMX), levofloxacin and minocycline was determined by disk diffusion. Minocycline testing was repeated with acceptable quality control, and the repeat-run zone records were reassessed using current CLSI breakpoints. A predefined, hypothesis-driven PCR panel was used to screen selected resistance-, efflux- and biofilm-associated targets, and gyrA, gyrB, parC and parE were sequenced. Genetic relatedness was assessed by XbaI-PFGE. Three selected isolates (S05, S08 and S25) underwent WGS as a targeted genomic-context analysis rather than a whole-collection population-genomic study.