Real-Time PCR Targeting the penA Mosaic XXXIV Type for Prediction of Extended-Spectrum-Cephalosporin Susceptibility in Clinical Neisseria gonorrhoeae Isolates.

Neisseria gonorrhoeae isolates with decreased susceptibility to extended-spectrum cephalosporins (ESCs) are increasing. We developed an assay to predict N. gonorrhoeae susceptibility to ESCs by targeting penA mosaic XXXIV, an allele prevalent among U.S. isolates with elevated ESC MICs. The assay was 97% sensitive and 100% specific for predicting at least one ESC MIC above the CDC alert value among clinical isolates, and it could be multiplexed with a previously validated gyrA PCR to predict ciprofloxacin susceptibility.