High-resolution melting assay for the detection of gyrA mutations causing quinolone resistance in Salmonella enterica serovars Typhi and Paratyphi.

We developed a novel rapid assay to detect the gyrA mutations that cause quinolone resistance in typhoid and paratyphoid fever Salmonella spp. using high-resolution melting (Idaho Technology, Salt Lake City, UT) analysis of polymerase chain reaction amplicons. The presence of gyrA mutations led to small but consistent changes in amplicon melting temperatures that allowed quinolone-resistant isolates to be differentiated from susceptible ones.