By age, our study population consisted of 182 women aged 17 to 50 years with an average age of 27.12 ± 6.09 years. Our study population appears young compared to that of Mamadou et al. who found in 2000, during their study of 529 female professionals in Niamey, an average age of 29 years and age extremes ranging from 16 to 65 years (15). Our cohort is composed of 9 different nationalities. Most of the countries concerned border on Burkina Faso and therefore this has facilitated easy access to these women. They migrated to Ouagadougou because they found easy access and also because they did not want to be recognized in their own country as commercial sex workers. Many of them could be seeking easy gain and also lack the necessities for their survival and perhaps for that of their families. Many of them may have entered the sex trade for economic reasons, as it may be the only employment opportunity, or the one that pays the best. Others may have entered the sex trade because they are trapped in violence, trafficking or debt. Some, especially adults, may have freely chosen the profession of commercial sex work. Entry into the sex trade may have socially entrenched causes, referring to traditions, beliefs and norms that perpetuate gender inequalities (27).
The number of sexual partners and marital status (single and married) were statistically associated with the presence of the pathogens NG, CT, MG: (p ˂ 0.001). Also, age group, number of sexual partners and marital status were statistically associated with HPV carriage (p ˂ 0.001). Indeed, in our study population, single women were dominant with 160 (87.91%), followed by married women with 7.14% or 13 women and finally 8 divorced women or 4.40%. Among the single women, 31.88% were infected, i.e. 28.02% of the study population. It could be said that the high number of single women could be justified by the fact that such women are more likely to engage in commercial sex work in order to provide for their needs.
As for the level of education of the study population, it was found that women with secondary education were in the majority and those with university education were in the minority. Ninety-nine (99) patients had a secondary level; 41 had a primary level. The education group most exposed to the infections encountered was those with secondary school education (62% of the infected population and 19.78% of the study population), followed by those with primary school education (20% of the infected population or 06.59% of the study population). These results are different from those of Mamadou et al. whose study population were sex workers who had parallel activities: bar waitresses and petty traders, and 27% of the study population were enrolled in school (15).
Of the four pathogens investigated in our study, Neisseria gonorrhoeae (NG); Chlamydia trachomatis (CT); Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV), three were present at varying prevalence.
NG was positive at 13.74%; the prevalence of Neisseria gonorrhoeae was lower in our study than the 20.5% and 22% reported in other studies conducted in Cotonou, Benin in 1999 (28) and Dakar in 2000 (29). Another study in Niamey, Niger, reported a prevalence of 5.67% of N. gonorrhoeae which was isolated from 30 endocervical specimens, and identified only on direct examination by the presence of Gram-negative diplococci, in "coffee bean", intra- and extra-leukocytic in 7 other cases. We note here that the Niamey study is different from ours due to the classical detection technique used and the results obtained (15).
The prevalence of CT infection in this study was 11.54% or 21 positive women. This rate is higher than those found in other studies in Cotonou in 1999 (5.1% (29)), Accra in 2000 (10.1%) (30) and Yaoundé in 1998 (12%) (31). Studies of low-risk women in different African countries have shown a prevalence of Chlamydia trachomatis infections ranging from 0.6% among women attending antenatal clinics in Tunisia to 5.5% in the general female population in the Gambia (32). However, the Mamadou study in Niger found higher results than ours (68.2% or 361/529 cases of active Chlamydia trachomatis infection in antigen detection) (15). Similarly, in Indonesia, studies among sex workers have shown prevalence rates of Chlamydia trachomatis infection ranging from 12–39%, while in Bangladesh, among sex workers in brothels, the prevalence rate was 15.5% (32). The prevalence of these STIs is higher in at-risk groups such as female sex workers than among women in the general population. Female sex workers are therefore said to be a reservoir for transmission to partners of those who use their service. Surveillance for these germs should therefore be strengthened.
MG also gave a prevalence of 11.54%. In their study, Mamadou et al. did not obtain Mycoplasma Genitalium but rather Mycoplasma hominis, which infected about 37% of the female sex workers in their study; it is involved in bacterial vaginosis sometimes complicated by endometritis and salpingitis (15). In this study, TV was not found. However, 10 patients were co-infected, including six (6) co-infections with CT and MG; three (3) co-infections with NG and CT and one co-infection with NG, CT and MG, i.e. a percentage of 5.49 co-infections. In a study conducted by Forward on the risk of co-infection with Chlamydia trachomatis and Neisseria gonorrhoeae in Nova Scotia, the co-infection rate was 31 out of 1495 patients for NG and CT (33). In another study by PETER et al, in patients infected with MG, co-infection of up to 40% with other microorganisms such as CT, NG or TV was found. This may draw our attention to co-screening for MG infection. The study population in this study is different from their study population, which justifies the difference in the exposure rate to the microorganisms (34, 35).
In terms of HIV status, most of the patients in this group of female sex workers had negative HIV status. While 6 had unknown HIV status, 7 were HIV positive. There is a low prevalence of HIV-positive status; however, several studies have shown that genital infections and STIs can increase HIV infectivity and/or transmission during sexual intercourse (3, 36, 37). This low rate of positive HIV status may be explained by the fact that most sex with female sex workers is protected or patients may not have answered truthfully to the question about their HIV status. In a study conducted in Niger in 2003, of 529 female sex workers enrolled, 30.1% were infected with HIV (15).
HPV-associated vaginosis co-infection was noted in 85% of cases in this study. This high rate of co-infection has the following combinations: HPV/NG; HPV/CT; HPV/MG; HPV/NG/CT; HPV/NG/MG and HPV/CT/MG with a statistically significant difference for HPV/NG and HPV/NG/MG. This association of STIs among sex workers in this investigation would increase the risk for their sexual partners. Indeed, although genital infections are often asymptomatic in women, the presence of a low genital infection would increase the risk of contracting HPV. For example, bacterial vaginosis is believed to be associated with high levels of anaerobic organisms that can damage the vaginal epithelium and thus increase the risk of HPV infection. In addition, Coudray and Madhivanan reported that bacterial vaginosis may increase the risk of many sexually transmitted infections (STIs) such as human immunodeficiency virus (HIV), Neisseria gonorrhea (NG), Chlamydia trachomatis (CT), Trichomonas vaginalis (TV), and herpes simplex-2 virus (HSV-2) (38).
In addition, female sex workers constitute a "reservoir" of STIs, which would further increase the risk of genital infection for the general population. HPV co-infection with pathogens such as NG, CT, MG and TV have been reported by other authors such as Coudray and Madhivanan in 2020 in the USA and Lv and al. 2019 in China (38, 39).
HPV is the leading cause of cervical cancer, which is the leading cause of cancer death in women in Africa. It is therefore a real public health problem, especially since the circulating genotypes are not covered by existing and available vaccines (40). From the perspective of integrated control, it would be beneficial to perform multiplex PCR for the molecular diagnosis of these pathogens (HPV, NG, CT, MG, TV) both in sex workers and in the general population. Thus, the treatment of these pathogens detected would make it possible to break the chain of transmission of these genital infections for the health of populations.
With regard concerned to resistance genes, our study revealed the presence of several genes hosted by the different species studied. These resistance genes were also identified in previous studies in Burkina Faso but in other biological samples such as urine, faecal matter and pus (41–43). In contrast to our study in which bla QNR B is predominantly represented, the study by Metuor Dabiré and al.; in 2013, showed a predominance of bla CTX−M (43). The coexistence of several resistance genes observed in the present study was also detected in previous studies in Burkina Faso (44, 45).
This coexistence of several resistance genes within bacteria is believed to confer multidrug resistance to antibiotics.
Conclusion
Beyond all the control that has been done so far against genital infections and STIs, with the administration of antimicrobials in order to destroy their reserve foci, and to consider means of control for their definitive eradication, this study conducted showed that the majority of female sex workers of West and Central African origin, working in the city of Ouagadougou in Burkina Faso, were infected with NG, MG, CT and HPV. This confirms that the presence of genital infections and STIs remains a real public health problem. This magnitude of genital infections and STIs among female sex workers in West and Central Africa and the detection of associated resistance genes calls for increased surveillance of the molecular epidemiology of these pathogens. Notwithstanding the relatively high cost of PCR, it should be recommended for the detection of these pathogens and the identification of their resistance genes.