Molecular epidemiology of Neisseria gonorrhoeae strains circulating in Indonesia using multi-locus variable number tandem repeat analysis (MLVA) and Neisseria gonorrhoeae multi-antigen sequence typing (NG-MAST) techniques

Background: Control of gonorrhea in resource-limited countries, such as Indonesia, is mostly unsuccessful. Examining Neisseria gonorrhoeae (Ng) transmission networks using strain typing might help prioritizing public health interventions.

Methods: In 2014, urogenital Ng strains were isolated from clients of sexually transmitted infection clinics in three Indonesian cities. Strains were typed using Multiple-Locus Variable Number Tandem Repeat (VNTR) Analysis (MLVA) and Ng Multi-Antigen Sequence Typing (NG-MAST) at the Public Health Service, Amsterdam, the Netherlands, and compared to Dutch strains collected from 2012 to 2015. Minimum spanning trees (MSTs) were constructed using MLVA profiles incorporating demographics and NG-MAST genogroups. A cluster was defined as ≥5 strains differing in ≤1 VNTR locus. The concordance between MLVA and NG-MAST was examined with the adjusted Wallace coefficients (AW).

Results: We collected a total of 78 Indonesian strains from Yogyakarta (n = 44), Jakarta (n = 25), and Denpasar (n = 9). Seven MLVA clusters and 16 non-clustered strains were identified. No cluster was specific for any geographic area, risk group or age group. Combined with 119 contemporary Dutch strains, 8 MLVA clusters were identified, being four clusters of Indonesian strains, two of Dutch strains, and two of both Indonesian and Dutch strains. Indonesian strains (79.5%) were more often clustered compared to Dutch strains (24.3%). The most prevalent NG-MAST genogroups among Indonesian strains was G1407 (51.3%) and among Dutch strains was G2992 (19.3%). In Indonesian strains, the AW [95% confidence interval] for MLVA to NG-MAST was 0.07 [0.00-0.27] and for NG-MAST to MLVA was 0.03 [0.00-0.12].

Conclusion: Indonesian Ng strains are more often clustered than Dutch strains, but show no relation with geographical area, risk group, or age group, suggesting a more clonal Ng epidemic in Indonesia. Some similar Ng strains circulate in both Indonesia and the Netherlands.