Diagnóstico e genotipagem de Trichomonas vaginalis em mulheres no sul do Rio Grande do Sul, Brasil

Abstract

Trichomonas vaginalis infection is globally the most common non-viral sexually transmitted infection and can result in many adverse health consequences during pregnancy and, especially, exacerbate the contagion and HIV transmission. T. vaginalis detection in women is performed by wet mount, a fast, easily performed, and low-cost technique. However, this method of diagnosis has low sensitivity, causes unknown prevalence and many cases are not treated. In addition, little is known about the genetic diversity of this protozoan, which leads to the search for greater understanding due to the health consequences, drug resistance and new diagnostic alternatives. The aim of this work was to study the epidemiology, diagnosis and genetic characterization of T. vaginalis in women attended at the Medicine School of UFPel in the south of Rio Grande do Sul, Brazil. Sample and data collection were obtained from August 2015 to June 2019. For the diagnosis, the samples collected were analyzed by wet mount, Gram stain, culture and nucleic acid amplification test (NAATS). The analyzes were carried out at the Parasitology Laboratory of the Biology Institute of the Federal University of Pelotas and at the University of Örebro, Sweden. Among the results, prevalence rates of 4.2%, 2.4%, 1.2% and 0%, were found using the Aptima TV test, culture, wet mount and Gram stain, respectively. The sensitivity of the culture and wet mount was 57.1% (95%, CI 36.5 - 75.5) and 28.6% (95%, CI 13.8 - 50.0), respectively. For the genetic characterization, Multilocus Sequence Typing (MLST) method was used to genetically characterize 10 previously obtained T. vaginalis isolates. Two types of population were found, 20 polymorphic sites and 22 alleles. Of these alleles, 3 were still unknown - two alleles for the DNA mismatch repair protein genes and 1 allele for the Mannose-6-phosphate-isomerase genes. The high genetic diversity and the assortment of isolates within type 1, call attention to greater pathogenicity to the parasite. Evidence of genetic recombination has also been identified, indicating that the protozoan may not be a clonal organism. This study has revealed that wet mount detects less than half of the cases, and the type 1 population of the parasite have predominated in our isolates, precisely the most pathogenic.