Epidemiology of Laboratory Confirmed Mucosal and Disseminated Gonococcal Infections in South Africa, 2012–2021

Abstract

Background Gonorrhoeal disease, caused by Neisseria gonorrhoeae is an important sexually transmitted infection (STI). With global guidelines recommending moving from syndromic management to aetiological screening and diagnostic testing of STIs, laboratory identification of gonococcal infection is of importance. Disseminated gonococcal infections (DGI) are well characterized manifestations of gonococcal infections. In South Africa the extent of DGI and the sites involved as well as overall gonococcal infections has not been fully studied or described. Methods This study was a retrospective analysis spanning 10 years, utilizing specimen data obtained from the Laboratory Information System (LIS) of the National Health Laboratory Service (NHLS), covering public health facilities across South Africa. Data was obtained on specimens collected from patients who were 15 years and older at both mucosal and disseminated sites and where N. gonorrhoeae testing was requested. Human Immunodeficiency Virus (HIV) status of study individuals was determined based on CD4 count and HIV viral load. South African population data for each study year was collected from PopulationPyramid.net for those 15 years and older and this was used to calculate testing rates expressed per 1 000 000 per population. Testing rates were also calculated for each province also expressed per 1 000 000. Median and Interquartile ranges were used to describe the age of those who tested positive for N. gonorrhoeae. Frequencies and percentages were used for sex, province, specimen site, location of infection – mucosal vs disseminated, year of specimen collection and HIV status. Results 4804 samples were sent to the NHLS laboratories for gonococcal testing over the study period. The highest testing rates were recorded in 2019, reaching 19.7 per 1 000 000 population. 2646 samples had valid results and were used to determine the prevalence. The overall prevalence of laboratory confirmed gonococcal infections was 20% over the 10-year period. Highest percentage of cases was noted in 2015 of 76% and lowest in 2012 of 0%. Females accounted for 60% of total gonococcal infections diagnosed. Disseminated gonococcal infection (DGI) rate was 18% of confirmed gonococcal infections with synovial fluid accounting for the main (61%) disseminated 3 site. 40% of gonococcal cases had laboratory confirmed HIV positive status, of which 38% were mucosal infections and 49% disseminated infections (p=0.048). Conclusion Gonococcal infections remain important STIs. There was varied prevalence over the different provinces and across the years with a predominant female occurrence. The most common DGI specimen was synovial fluid which is in keeping with various studies. Due to limitations with culture testing and laboratory reporting, underreporting of the burden of disease is expected and further studies including clinical data or patient records may allow for further determination of missing data and clinical spectrum related to DGI.