Development of a Luminex xTAG Assay for the Rapid Detection of Five Aminoglycoside Resistance Genes Both in Staphylococci and Enterococci

Resistance to aminoglycoside antibiotics is now common in pathogenic bacteria, making treatment of infections difficult. The rapid spread of resistance is mainly related to the dissemination of genes encoding aminoglycoside-modifying enzymes (AMEs). Staphylococci and enterococci are opportunistic human pathogens capable of causing a wide range of infections. Isolates from clinical cases are often found to be resistant to aminoglycosides. The aim of the present study was to develop a bead-based xTAG assay for the simultaneous detection of five prevalent aminoglycoside resistance genes in staphylococci and enterococci, including aac(6′)-Ie-aph(2″)-Ia, aph(3′)-IIIa, ant(4′)-Ia, ant(9)-Ia, and ant(6)-Ia. The limit of detection ranged from 10 to 1000 copies/μL of input purified plasmid DNA. Twenty-two bacterial isolates from clinical samples were examined using the newly developed xTAG assay and also by conventional PCR to determine the relative performance of each. The results obtained by xTAG assay showed higher detection rates and accuracy for AME genes than conventional PCR. It indicated that the xTAG-multiplex PCR method is a high-throughput tool for rapid identification of AME genes.