Antimicrobial resistance and molecular characteristics of N. gonorrhoea isolates in Ghana

Introduction: Gonorrhoea is a disease associated with humans and caused by N. gonorrhoea. N. gonorrhoea’s ability to evolve and evade various treatment regimens can lead to untreatable gonorrhoea. In the absence of a viable vaccine, a national database on antimicrobial resistance (AMR) and molecular characteristics of N. gonorrhoea, and the reliance on a syndromic management regime, continuous national antimicrobial resistance surveillance and molecular characterisation of N. gonorrhoea remain imperative. Only two gonococcal studies have described its molecular characteristics linked to AMR in Ghana. Methods: Secondary N. gonorrhoea isolates (n=4) were collected from two metropolises in Ghana: Tamale in the northern sector (n=1) and Accra in the southern sector (n=3). The isolates were confirmed and characterised using polymerase chain reaction (PCR) targeting the porB and tbpB genes, and the disk diffusion method was used to evaluate antimicrobial resistance (AMR). N. gonorrhoea Multi-Antigen Sequence Typing (NG-MAST) and porin B (porB) gene sequence analyses were used to reveal molecular epidemiology and evolutionary trajectory, respectively. Results: All four isolates showed resistance to at least four of the tested antibiotics. One isolate showed resistance to all seven antibiotics, i.e. Ceftriaxone, Azithromycin, Ciprofloxacin, Tetracycline, Erythromycin, Togamycin and Penicillin.  NG-MAST typing revealed isolates S3 (MZ313864) as ST211. The locus of S2 (MZ313863) (transferrin binding protein B; tbpB) was identified as tbpB1844, and its porin, porB locus, as porB6412 with only four closely related variants but with 15 nucleotide differences. However, its sequence type does not exist. The PorB analysis identified isolate S3 (MZ313864) to be found globally, while S2 (MZ313863) is unique to this study. Discussion: Despite the small number of isolates tested, this study recorded multidrug resistance and previously unknown gonococcal variants. Additionally, the molecular typing schemes revealed a disparity between NG-MAST and NCBI. There is a need for continuous gonococcal AMR and molecular surveillance in Ghana to contribute to the global efforts of describing circulating strains and to support a proper application of the syndromic management regime to gonorrhoea.