Gonorrhea, Chlamydia and HIV incidence among female sex workers in Cotonou, Benin: A longitudinal study

<div><p>Female sex workers (FSWs) continue to carry a heavy burden of sexually transmitted infections (STI). For prevention purposes, there is a need to identify most-at-risk subgroups among them. The objective of this longitudinal cohort study conducted at <i>Dispensaire IST</i>, Cotonou, Benin, was to assess <i>Neisseria gonorrhoeae</i> (NG) / <i>Chlamydia trachomatis</i> (CT) incidence and determinants; and HIV incidence among FSWs in presence of STI/HIV risk reduction activities. Overall, 319 adult FSWs were followed quarterly from September 2008 to March 2012. NG/CT were detected from endocervical swabs by Amplified DNA Assays employing Strand displacement amplification technology. HIV testing was done on capillary blood using two consecutive rapid diagnostic tests. Anderson-Gill proportional hazard models (HR) were used to determine factors independently associated with NG/CT incidence. The majority of FSWs were HIV-negative (188, 58.9%). There were 6 HIV seroconversions among these 188 HIV-negative women. HIV incidence (95% Confidence interval, CI) was 1.41 (0.28–2.54) seroconversions per 100 person-years at risk (PYAR): 6 events / 425.1 PYAR. Sixty-two out of 319 women experienced 83 new episodes of NG/CT for an overall incidence rate (95% CI) of 10.8 (8.17–13.88) events / 100 PYAR. From month-24 onwards, HIV-positive women (treated: HR (95%CI): 4.2 (1.60–10.77); untreated: HR (95%CI): 4.2 (1.59–11.49) were more likely to acquire NG/CT compared to HIV-negative FSWs. Longer duration in sex work (>2 years: HR; 95%CI: 0.4 (0.22–0.72)) was protective against NG/CT. Refusal by clients (55.8%) was the main reason for non-condom use. Enrolling women from one clinic (<i>Dispensaire IST</i>) may have impaired generalizability of the findings. New NG/CT/HIV infections were observed among FSWs notwithstanding ongoing prevention interventions. To eliminate HIV transmission among FSWs, STI/HIV control programs need to promote women’s empowerment and address vulnerability to infection of HIV-positive FSWs.</p></div

Baseline characteristics of 319 female sex workers, Cotonou, Benin, 2008–2012.

<p>Baseline characteristics of 319 female sex workers, Cotonou, Benin, 2008–2012.</p

Variation in crude NG/CT incidence rates in a cohort of 319 female sex workers, in Cotonou, Benin, 2008–2012.

<p>Variation in crude NG/CT incidence rates in a cohort of 319 female sex workers, in Cotonou, Benin, 2008–2012.</p

<i>Legionella pneumophila</i> outbreaks investigated by LSPQ between 2005 and 2015.

<p><i>Legionella pneumophila</i> outbreaks investigated by LSPQ between 2005 and 2015.</p

Number of cases per year, by species and serogroup, and annual incidence rate of legionellosis, province of Quebec, 1990–2015.

<p>Number of cases per year, by species and serogroup, and annual incidence rate of legionellosis, province of Quebec, 1990–2015.</p

eBURST analysis of <i>Legionella pneumophila</i> SG1 sequence type.

<p>Panel A shows the 141 sporadic cases of our study. Full lines link single-locus variants and dashed lines double-locus variants. Group numbers are also indicated. Panel B shows the group 2 of the EWGLI-SBT database eBURST analysis from SG1 strains. Sequence types in pink are from our study. Blue dot represent the primary founder and yellow dots the subfounders. For both panels, the size of the dot is proportional to the number of isolates in the analysed collection.</p

Sequence type (ST) distribution amongst legionellosis sporadic cases and their serogroup between 2005 and 2015 (n = 141).

<p>For ST-1327, 1 isolate has cross reaction with serogroup 5 and 9 antibodies. For ST-378, 1 isolate was from serogroup 10 and 3 has an inconclusive serogroup.</p

<i>Legionella pneumophila</i> environmental isolates typed at LSPQ between 2005 and 2015.

<p><i>Legionella pneumophila</i> environmental isolates typed at LSPQ between 2005 and 2015.</p

Misidentification by both systems when the microorganisms is referenced in the database.

<p>^aBruker Biotyper confidence value is up to 3.0, and VITEK MS is up to 100.</p><p>Misidentification by both systems when the microorganisms is referenced in the database.</p

Algorithm for results analysis.

<p>Samples were assessed for the presence of <i>S. pneumoniae</i> by detecting the pneumolysin and the autolysin genes. If <i>S. pneumoniae</i> was detected in the sample, the serotyping probes were analyzed in order to identify the serotype.</p