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Research Letter
Cross-sectional study of patients tested for STIs using molecular methods in Brazil
  1. Feliciana Lage Marinho,
  2. Danielle Zauli
  1. Research & Development Division, Hermes Pardini Institute, Vespasiano, Minas Gerais, Brazil
  1. Correspondence to Dr Danielle Zauli, Hermes Pardini Institute, 33200-000 Belo Horizonte, Brazil; danielle.zauli{at}

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STIs represent an important global public health problem due to the high morbidity and mortality associated with them, and also due to the involvement of more than one pathogen, which makes the diagnosis challenging and increases the cost associated with the treatment of these infections.1–3 According to WHO, more than 1 million STI cases are reported every day worldwide.4 In Brazil, it is estimated that there are 10 to 12 million new cases annually.2 More than 30 different micro-organisms have been found to cause STIs, and some of them are linked with higher incidence such as Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Ureaplasma urealyticum (UU), Mycoplasma hominis (MH), Mycoplasma genitalium (MG) and Trichomonas vaginalis (TV).5 Due to certain factors related to STIs such as overlapping clinical symptoms among these diseases, high treatment cost, impact on sexual and reproductive health worldwide and elevated risk of HIV infections, it is imperative to study the prevalence of these infections. These studies will allow a better view of the epidemiological scenario and, as a result, facilitate the control measures and effective treatment to reduce the morbidity in sexually active individuals. The aim was to investigate the prevalence of C. trachomatis, N. gonorrhoeae, U. urealyticum, M. hominis, M. genitalium and T. vaginalis infections among individuals of both sexes using molecular detection methods. This is a retrospective and cross-sectional study consisting of a scientific research involving query of results database from patients from Brazil during the period of January 2008 to June 2019. The patients’ identities were not unveiled. The inclusion criteria consist of detection of DNA belonging to one or more micro-organisms using PCR in routine laboratory practice. For the screening of infectious agents, we used DNA detection methods to find one or more micro-organisms using PCR. The prevalence estimates were calculated using statistical procedures suitable for the collected data using the IHP database. Out of 69 147 samples analysed, 23 202 (33.6%) were positive for one or more agents. The mean age of the patients was found to be 34.74 years. The highest number of positive cases (30.7%) was reported from the Southern region, followed by the Northeast region (29.3%) and Southeast region (27.3%). Among the positive samples, the presence of a single micro-organism was found in 19 530 samples (84.17%) figure 1. U. urealyticum was the most prevalent micro-organism (62.47%), followed by M. hominis (9.31%) and C. trachomatis (9.27%). Among the patients with coinfection, 3300 (14.22%) were found to be coinfected by M. hominis/U. urealyticum. Our results revealed the importance of estimating the prevalence of pathogens in patients suffering from STIs of both sexes. This will ensure that effective interventions for the prevention of STIs such as screening, diagnosis and treatment are made more widely available.

Figure 1

(A) Distribution of infectious agents in monoinfection and coinfection according to sex. (B) Distribution of STI positive and negative samples according to different regions of Brazil.


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  • Handling editor Anna Maria Geretti

  • Contributors Contributors FLM and DZ collaborated in the design, conducting and writing of the manuscript.

  • Funding This study was funded by Hermes Pardini Institute.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; internally peer reviewed.

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