DNA microarray for genotyping multidrug-resistant Pseudomonas aeruginosa clinical isolates.

The management of infections with multidrug-resistant Pseudomonas aeruginosa needs fast and reliable methods of antibiotic susceptibility testing for a therapy improvement. For this purpose, we developed a DNA microarray for genotyping antibiotic resistance and a few virulence factors. The array covers mutations in the efflux regulators mexR, nfxB, mexT, gyrase gyrA, and parC, as well as plasmid-encoded vim, imp, oxa, aph, aac, and aad genes, and virulence-associated mucA and exoU, exoT, and exoS genes, respectively. The whole procedure can be performed in less than 5 h and consists of DNA isolation, target gene amplification, fluorescence labeling, fragmentation, and array hybridization. Concerning the genotype-phenotype comparison in the test collection, the coverage of relevant resistance determinants for antibiotics used in a calculated therapy of critical ill patients was 87.8%.