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

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-MAST)2212/ST(MLST)1901 (n = 1); ST(NG-MAST)3149/ST(MLST)1901 (n = 1); ST(NG-MAST)5622/ ST(MLST)14011 (n = 1), and ST(NG-MAST)10025/ST(MLST)1902 (n = 4) sequence types. Phylogenetic analysis has linked all named sequence types to the internationally spread, multiresistance clone ST(NG-MAST)1407/ ST(MLST)1901, 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.

Automated summary

The study aimed to molecularly type Neisseria gonorrhoeae clinical isolates in Russia to identify epidemiologically significant sequence types carrying a penA gene allele with reduced sensitivity to third-generation cephalosporins. The study revealed the diversity of current N. gonorrhoeae sequence types carrying the mosaic penA gene allele and identified a multi-resistance clone of global public health concern.