Neisseria gonorrhoeae and Extended-Spectrum Cephalosporin Resistance: A Study of Ceftriaxone-Resistant Isolates (2010–2014) in France Using Whole Genome Sequencing. ESC-resistant N. gonorrhoeae in France

Neisseria gonorrhoeae isolates with resistance to extended-spectrum cephalosporins (ESCs) have emerged worldwide. These isolates often harbor multidrug resistance leading to treatment failures. In France, the first strain F89 with high-level resistance to ceftriaxone was isolated in 2010. Here, we conducted a surveillance study from January 2010 to December 2014. The MICs of seven antibiotics, including ESCs, were determined for 6,342 N. gonorrhoeae isolates collected in France via the sentinel network of laboratories. A total of 88 (1.39%) and 2 (0.03%) N. gonorrhoeae isolates were found to be resistant to cefixime and ceftriaxone, respectively. The 2 ceftriaxone-resistant N. gonorrhoeae isolates (MIC 0.25 mg/liter, and 2 mg/liter for the F89 isolate) and the 2 isolates for which the MIC to ceftriaxone was equal to the breakpoint of the molecule (0.125 mg/liter) were characterized by whole genome sequencing. Resistance resulted from the penA mosaic alleles (XXXIV family and XXXVI) associated with other determinants of resistance. The isolates were clonally related to the F89 isolate by the multilocus sequence typing ST1901,or to ST1579 and belonged to N. gonorrhoeae multi-antigen sequence typing (NG-MAST) ST1407, ST225, ST3378, and ST6711. In France, the proportion of N. gonorrhoeae isolates with resistance to ESCs remains low. The F89 strain has not disseminated widely, and the main clone circulating in France belongs to the sequence type ST1901 (NGMAST 1407). Continuous monitoring of this resistance is fundamental to the control of multidrug-resistant gonorrhea.