Molecular characterization of a ceftriaxone-resistant Neisseria gonorrhoeae strain found in Switzerland

Abstract Background: Resistance of Neisseria gonorrhoeae to ceftriaxone is very rare in Switzerland. The underlying genotype is suspected to be novel. Generally, resistance in Neisseria gonorrhoeae (Ng) involves a comprehensive set of genes with many different mutations causing resistance to different β-lactams and fluoroquinolones.Case presentation: A patient had a positive result with specific PCR for Ng. We routinely start culturing for all clinical specimens with a positive result with NG-PCR. In this particular case, we isolated such a strain with resistance to ceftriaxone in Switzerland. A total of 7 different genes in this strain were partially sequenced for comparison with phenotypic susceptibility testing. Interestingly, two different mutations in the porinB gene were observed, and data on this gene are limited. Information on the identified allele type of the penA gene is very limited as well. Three different mutations of parC and gyrA that correlate with ciprofloxacin resistance were found.Conclusion: The combined results for all genes show the appearance of new mutations in central Europe either due to worldwide spread or the emergence of new genetic combinations.