Diversity of NG-MAST and MLST Sequence Types in Russian Clinical Isolates of Neisseria gonorrhoeae Carrying the “Mosaic” Allele of the penA Gene

Abstract—The goal of the study was molecular typing of current Neisseria gonorrhoeae clinical isolates in Russia for the identification of epidemiologically significant NG-MAST and MLST sequence types carrying a “mosaic” penA gene allele with reduced sensitivity to third-generation cephalosporins, which are recommended as first-line antimicrobials for gonococcal infection therapy. The study included 326 N. gonorrhoeae clinical isolates collected in Russia in 2018–2020. NG-MAST typing was based on sequencing of variable regions of porB and tbpB genes. MLST typing was performed on the basis of the nucleotide sequences of seven housekeeping genes: abcZ, adk, aroE, fumC, gdh, pdhC, and pgm. The penA gene structure was analyzed according to the Sanger protocol. Molecular typing assigned the examined N. gonorrhoeae clinical isolates to 110 NG-MAST and 41 MLST different sequence types. The penA gene sequencing revealed a “mosaic”-type XXXIV allele encoding penicillin-binding protein 2 with reduced affinity to cephalosporins in 7 (2.1%) clinical isolates. Comparison of these results showed the presence of a “mosaic” penA allele in clinical isolates related to ST_NG-MAST2212/ST_MLST1901 (n = 1); ST_NG-MAST3149/ST_MLST1901 (n = 1); ST_NG-MAST5622/ ST_MLST14011 (n = 1), and ST_NG-MAST10025/ST_MLST1902 (n = 4) sequence types. Phylogenetic analysis has linked all named sequence types to the internationally spread, multiresistance clone ST_NG-MAST1407/ ST_MLST1901, which is a public health concern globally. The study showed the diversity of current N. gonorrhoeae sequence types carrying the “mosaic” penA gene allele, probably as a result of novel mutational events in the porB, adk, and fumC genes taken into account by the NG-MAST and MLST protocols.