Detection of molecular resistance patterns in N. gonorrhoeae to extended-spectrum cephalosporins, ciprofloxacin and spectinomycin from primary vaginal swabs

Abstract

Objective: Antimicrobial-resistant Neisseria gonorrhoeae is a public health concern. This study determined antimicrobial resistance (AMR) patterns in vaginal swabs testing positive for N. gonorrhoeae.
Methods: In total, 385 pregnant women were enrolled in this study. Vaginal swabs were collected from consenting women and used for the detection of N. gonorrhoeae using the TaqMan assay. Genes containing known mutations associated with resistance to azithromycin, spectinomycin, ciprofloxacin and extended-spectrum cephalosporins (ESCs) in N. gonorrhoeae were investigated using a quantitative polymerase chain reaction (PCR) assay. To validate the PCR assay, N. gonorrhoeae cultured isolates with known antimicrobial profiles were used as controls in the mutation detection assays.
Results: The prevalence of N. gonorrhoeae in the study population was 4.1% (16/385). The validation assays showed a positive correlation between phenotypic and genotypic data for ESCs, ciprofloxacin and spectinomycin resistance profiles only. Of the 16 N. gonorrhoeae-positive clinical samples, the Ser91Phe mutation carried on the gryA gene was detected in 6/16 samples (37.5%). The penA gene carrying the Gly545Ser mutation was shown to be present in 1/16 samples (6.25%). Within the same gene, the Asp345del mutation, which also confers decreased susceptibility or resistance to ESCs, was not detected. Approximately 6.25% of the samples carried the C1192T mutation in the 16S rRNA gene associated with spectinomycin resistance.
Conclusion: Molecular-based assays for tracking resistance patterns may serve as an attractive alternative for antimicrobial surveillance.