Discussion
Despite the small number of isolates tested, this study recorded multidrug resistance and previously unknown gonococcal variants based on porB gene. Additionally, the molecular typing schemes revealed a disparity between NG-MAST and the National Center for Biotechnology Information (NCBI) platforms. There is a need for continuous gonococcal AMR and molecular surveillance in Ghana to contribute to the global efforts to describe circulating strains and support proper application of the syndromic management regime to gonorrhoea.
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 characterized using polymerase chain reaction (PCR) targeting the porB and tbpB genes, and the disc diffusion method was used to evaluate AMR. N. gonorrhoea multi-antigen sequence typing (NG-MAST) and porin B (porB) gene sequence analyses were employed to reveal the 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 isolate S3 (MZ313864) as ST211. The locus of S2 (MZ313863) (transferrin-binding protein B; tbpB) was identified as tbpB1844, and its porB locus, as porB6412, with only 4 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.