Date Published: April 23, 2019
Publisher: Public Library of Science
Author(s): Luana L. S. Rodrigues, Justin Hardick, Alcina F. Nicol, Mariza G. Morgado, Katrini G. Martinelli, Vanessa S. de Paula, José H. Pilotto, Charlotte A. Gaydos, R. Matthew Chico.
The anogenital prevalence of sexually transmitted infections (STIs) and the use of cervico-vaginal self-collected vs. clinician-collected samples were evaluated for the diagnosis of human immunodeficiency virus (HIV)-infected and HIV-uninfected women in the Tapajós region, Amazon, Brazil. We recruited 153 women for a cross-sectional study (112 HIV-uninfected and 41 HIV-infected) who sought health services. Anal and cervical scrapings and cervico-vaginal self-collection samples were collected. Real-time polymerase chain reaction methods were used for Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium. A syphilis test was also performed. Risk factors for STIs were identified by multivariate analysis. The overall prevalence of STIs was 30.4% (34/112) in HIV-uninfected women and 24.4% (10/41) in HIV-infected women. Anogenital Chlamydia trachomatis infection was the most prevalent in both groups of women (20.5% vs 19.5%). There was significant agreement for each STI between self-collected and clinician-collected samples: 91.7%, kappa 0.67, 95% confidence interval (CI) 0.49–0.85 for Chlamydia trachomatis; 99.2%, kappa 0.85, 95% CI 0.57–1.00 for Neisseria gonorrhoeae; 97.7%, kappa 0.39, 95% CI -0.16–0.94 for Trichomonas vaginalis; and 94.7%, kappa 0.51, 95% CI 0.20–0.82 for Mycoplasma genitalium. Women with human papillomavirus had coinfection or multiple infections with other STIs. Risk factors for STIs were being ≤ 25 years old, being employed or a student, reporting a history of STI and having a positive HPV test. A high prevalence of STIs in women in the Tapajós region was found. Cervico-vaginal self-collection is a useful tool for STI screening and can be used in prevention control programs in low-resource settings, such as in northern Brazil.
The World Health Organization (WHO) estimates that among adults aged 15–49 years there are 357 million new infections each year of either Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Trichomonas vaginalis (TV) or syphilis. This represents approximately one million new infections every day . Most of these infections are treatable with currently available antibiotics; however, antimicrobial resistance is a growing threat for NG, syphilis and Mycoplasma genitalium (MG) . If untreated, STIs can cause several serious complications and increased risks of human immunodeficiency virus 1 (HIV-1) acquisition and transmission and cancer .
This is the first study of STI prevalence detected by molecular testing in self-collected samples compared to clinician-collected samples in women living in the Tapajós region, Amazon, Brazil. In the present study, a high STI prevalence was identified, namely, 30.4% in HIV-uninfected women and 24.4% in HIV-infected women, as assessed by positivity in at least one of the three types of clinical specimens. This prevalence is much higher than the 2.1% detected in a previous multicenter study with HIV-infected women  and the 13.6% of women in the general population in Peru , but the prevalence was less than the 36.5% observed in HIV-infected pregnant women in northeastern Brazil  and the 60.6% observed in female sex workers in Peru . In this study, we found an overall prevalence of STIs slightly higher in HIV-uninfected women than in HIV-infected women, although this difference was not statistically significant. We believe that this can be explained by the differences in sample size distribution between the groups, which is a limitation of our study and is discussed more below. However, we believe that the overall prevalence of STIs in HIV-infected women should be higher because these women had a higher diversity of STIs, coinfections and multiple infections, and the seroprevalence of syphilis was also high in this study.
In summary, we identified a high prevalence of STIs and a significant positive agreement rate between self-collected and clinician-collected samples in this study. Considering these findings, we suggest the implementation of STI screening and prevention control programs in groups at high risk of acquiring and transmitting STIs, such as young women and HIV-infected women, especially in resource-limited settings and isolated regions of the country. In addition, further epidemiological studies are warranted to investigate the role of HPV with other STIs and the impact of CT and MG on HIV-infected and HIV-uninfected women living in the Tapajós region, Amazon, and other regions of Brazil.