Simple and Robust Array-Based Methods for the Parallel Detection of Resistance Genes of Staphylococcus aureus

The diagnostic use of DNA arrays in microbiology allows the simultaneous detection of a multitude of different target genes. To develop an array-based procedure that can be performed in a rou- tine diagnostic laboratory, Staphylococcus aureus was selected as a target organism. A DNA array com- prising probes for species-speciec controls, different genes for antibiotic resistance properties including mecA, and for the gene of the toxic shock syndrome toxin was constructed. This array was applied for hy- bridizations with labeled genomic DNA from clinical isolates of Staphylococcus aureus and from other Staphylococcus species. Labeling and detection of hybridizations were performed by four different proto- cols. These results were compared with each other and with data from conventional susceptibility testing showing a high degree of accordance. A protocol using a sequenase-driven random amplie cation followed by incorporation of biotin-labeled nucleotides and a detection by a streptavidin-gold-induced silver precipi- tation appeared to be the most sensitive and most economical method for the detection of hybridizations on the array. Thus, DNA arrays may become a useful tool for the study of the genetic epidemiology of an- timicrobial resistance, as well as for the rapid identie cation of staphylococcal toxins.