Molecular detection of fluoroquinolone-resistant by using mismatched PCR-restriction fragment length polymorphism technique.

Ciprofloxacin (CIP) is a commonly used antibiotic for meningococcal chemoprophylaxis, and the mutations in the quinolone resistance-determining region of are associated with CIP-resistant . Here, we established a mismatched PCR-restriction fragment length polymorphism (RFLP) assay to detect a mutation at codon 91 of , followed by high-level CIP-resistant meningococci. We designed PCR-RFLP primers to detect the T91I mutation in by introducing an artificial I cleavage site. This assay was performed using 26  strains whose sequences have been characterized. The amplified 160 bp PCR product from was digested into three fragments (80, 66, and 14 bp) when there was no mutation, or two fragments (146 and 14 bp) when there was a mutation at codon 91. A correlation was observed between the mismatched PCR-RFLP assay and sequencing. This rapid, simple, and accurate assay has the potential to detect CIP-resistant in clinical microbiology laboratories, contributing to the appropriate antibiotic selection for meningococcal chemoprophylaxis, will help maintain an effective treatment for close contacts of IMD patients, and prevent the spread of CIP-resistant .