Population structure and genetic diversity of the parasite Trichomonas vaginalis in Bristol, UK

The prevalence trends of Trichomonas vaginalis infection among women in Jingzhou, central of China, 2019-2023

BACKGROUND

Trichomonas vaginalis (T. vaginalis) is one of the most prevalent sexually transmitted infections globally, with significant regional variations in its prevalence. This study aimed to examine the epidemiological characteristics of T. vaginalis infection in Jingzhou, Hubei Province, China.

METHODS

To obtain the prevalence of T. vaginalis infection among age groups and different years, a total of 115,775 patients from 2019 to 2023 were included in this study. Two detection methods including immunochromatographic assay and wet mount microscopy were used to detect the pathogens in vaginal swabs samples including T. vaginalis with other vaginal pathogens, such as Candida albicans (C. albicans) and Gardnerella Vaginalis (G. vaginalis).

RESULTS

The overall prevalence of T. vaginalis in Jingzhou was 3.41%, demonstrating a decreasing trend from 2019 to 2023, with a particularly significant decrease during the COVID-19 pandemic in 2020-2022 (P < 0.001). The highest positive rate of T. vaginalis was observed in the 45-54 years age group (4.87%), while the lowest rate was observed in the 25-34 years age group (2.37%). The prevalence of T. vaginalis in pregnant women (0.83%) was lower than that in non-pregnant women (1.87%), with a statistically significant difference (P < 0.001). T. vaginalis had co-infection with other pathogens (2.76%) compared to single infection (0.65%), and the most common co-infection pattern was T. vaginalis and G. vaginalis (2.09%). The results showed that there was relative high consistency (Kappa: 0.841) between the immunochromatographic assay and wet mount microscopy method for the detection of T. vaginalis. Additionally, elevated leukocyte levels were associated with a higher prevalence of T. vaginalis.

CONCLUSION

The overall infection rate of T. vaginalis was 3.41%, showing a decreasing trend in prevalence in Jingzhou from 2019 to 2023. The prevalence was the highest in the 45-54 years age group. The study suggested that the immunochromatographic assay should be widely implemented as a screening method for T. vaginalis in primary healthcare facilities.

Microscopic and molecular detection of Trichomonas vaginalis in outpatients seeking medical care in Upper Egypt

Introduction

Trichomoniasis remains one of the most significant sexually transmitted disease (STDs) for public health. The disease is caused by parasitic protozoa, Trichomonas vaginalis (T. vaginalis), which is often underestimated in tropical medicine. Despite its public health importance, the epidemiology and molecular characteristics of trichomoniasis in Egypt remains poorly understood, particularly in the southern part of the country (Upper Egypt). This study targeted exploring the genetic variability of T. vaginalis infections in Egyptian women living in Upper Egypt using restriction fragment length polymorphism (RFLP).

Patient and techniques

This cross-sectional study included 150 female patients, who visited the gynaecology and obstetrics outpatient clinics at Sohag General Hospital between 2019 and 2022, exhibiting symptoms of trichomoniasis. Vaginal washout samples were collected from each patient and analyzed using three diagnostic techniques: direct wet mount microscopy, culture on TYM Diamond's medium, and PCR amplification and Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) targeting the actin gene, which was applied to all 16 samples that tested positive in culture. The PCR-RFLP results were then visualized through agarose gels electrophoresis to detect DNA fragments.

Results

Out of 150 vaginal washout samples, 12 cases (8%) tested positive for T. vaginalis trophozoites via direct wet mount microscopy, while 16 samples (10.6%) were positive in culture. Additionally, PCR-RFLP analysis of the 16 culture-positive samples revealed that 13 samples were confirmed positive using this molecular method. The amplified products were digested with the restriction enzyme Hind II, yielding three DNA fragments of 60, 213, and 827 bp, which were then detected by agarose gel electrophoresis. Digestion with RsaI produced five fragments measuring 87, 103/106, 236, and 568 bp, while MseI digestion resulted in three distinct fragments of 204, 315, and 581 bp.

Conclusion

This study provides robust baseline data on the prevalence and microscopic characteristics of T. vaginalis in Upper Egypt, while also presenting, for the first time, molecular detection and genotyping and revealed that genotype E is the only prevalent genotype in the region.

The sexual side of parasitic protists

Much of the vast evolutionary landscape occupied by Eukaryotes is dominated by protists. Though parasitism has arisen in many lineages, there are three main groups of parasitic protists of relevance to human and livestock health: the Apicomplexa, including the malaria parasite Plasmodium and coccidian pathogens of livestock such as Eimeria; the excavate flagellates, encompassing a diverse range of protist pathogens including trypanosomes, Leishmania, Giardia and Trichomonas; and the Amoebozoa, including pathogenic amoebae such as Entamoeba. These three groups represent separate, deep branches of the eukaryote tree, underlining their divergent evolutionary histories. Here, I explore what is known about sex in these three main groups of parasitic protists.

Molecular characterisation of Trichomonas vaginalis isolates in Southwest Turkey with multilocus sequence typing and genetic structure analysis in relation to different countries

Trichomonas vaginalis, a flagellated protozoan parasite, is among the most common sexually transmitted pathogens in the world. The present study aimed to identify the genetic profiles of T. vaginalis in the southwest of Turkey with multilocus sequence typing (MLST) and to analyse the genetic structure of the parasite in a collection of isolates from different countries. The study included 27 T. vaginalis isolates from symptomatic females in Aydin, Turkey. Seven housekeeping genes of T. vaginalis were partially amplified and sequenced after genomic DNA extraction from in vitro cultures. The allele profiles and sequence types (STs) of the isolates were determined by using the MLST database (https://pubmlst.org/tvaginalis). The genetic structure and differentiation of the parasite were analysed in relation to findings from other countries by assembling the available MLST sequences. When referred to the database, a total of 22 STs, including 18 new STs were found; besides, there were two new allele types. The genetic analysis of MLST data demonstrated the presence of two main genetic structures: Type I and Type II. In addition, the neighbor-joining method also revealed that the isolates were clustered into two groups. The genetic types distributed almost equally in the Netherlands and the USA, however, the predominance of Type I was noted in Turkey and the UK. The genetic differentiation among four countries was significant (p < .05), the gene flow was relatively high between the Netherlands and the USA, in contrast to Turkey. Finally, genetic variations were originated within populations (93.8%) rather than among populations (6.2%). In conclusion, we studied the genetic diversity of T. vaginalis isolates with MLST in the southwest of Turkey and showed the origin of genetic differentiation of the parasite among different countries. The presentation of MLST profiles and genetic variance of T. vaginalis isolates will contribute to the development of new diagnostic and treatment options for the parasite.

Population structure and genetic diversity of Trichomonas vaginalis clinical isolates in Australia and Ghana

Population genetic studies of Trichomonas vaginalis have detected high genetic diversity associated with phenotypic differences in clinical presentations. In this study, microscopy and next generation-multi-locus sequence typing (NG-MLST) were used to identify and genetically characterise T. vaginalis isolates from patients in Australia and Ghana. Seventy-one polymorphic nucleotide sites, 36 different alleles, 48 sequence types, 24 of which were novel, were identified among 178 isolates, revealing a geneticallly diverse T. vaginalis population. Polymorphism was found at most loci, clustering genotypes into eight groups among both Australian and Ghanaian isolates, although there was some variation between countries. The number of alleles for each locus ranged from two to nine. Study results confirmed geographic expansion and diversity of the T. vaginalis population. Two-type populations in almost equal frequencies and a third unassigned group were identified in this study. Linkage disequilibrium was observed, suggesting T. vaginalis population is highly clonal. Multillocus disequilibrium was observed even when analysing clades separately, as well as widespread clonal genotypes, suggesting that there is no evidence of recent recombination. A more comprehensive study to assess the extent of genetic diversity and population structure of T. vaginalis and their potential impact on varied pathology observed among infected individuals is recommended.

Prevalence and genetic diversity of Trichomonas vaginalis in the general population of Granada and co-infections with Gardnerella vaginalis and Candida species

PURPOSE

Purulent or exudative genitourinary infections are a frequent cause of consultation in primary and specialized healthcare. The objectives of this study were: to determine the prevalence of Trichomonas vaginalis and co-infections with Candida spp. and Gardnerella vaginalis in vaginal secretion; and to use multilocus sequence typing (MLST) to analyse the genetic diversity of T. vaginalis strains.

METHODOLOGY

The samples were submitted for analysis (n=5230) to a third-level hospital in Granada (Southern Spain) between 2011 and 2014; eight T. vaginalis strains isolated during 2015 were randomly selected for MLST analysis. Culture and nucleic acid hybridization techniques were used to detect microorganisms in the samples.

RESULTS

The prevalence of T. vaginalis was 2.4 % between 2011 and 2014, being higher during the first few months of both 2011 and 2012. Among samples positive for T. vaginalis, co-infection with G. vaginalis was detected in 29 samples and co-infection with Candida spp. in 6, while co-infection with all three pathogens was observed in 3 samples. The only statistically significant between-year difference in co-infection rates was observed for T. vaginalis with G. vaginalis due to an elevated rate in 2011. MLST analysis results demonstrated a high genetic variability among strains circulating in our setting.

CONCLUSION

These findings emphasize the need for the routine application of diagnostic procedures to avoid the spread of this sexually transmitted infection.

Direct detection of Trichomonas vaginalis virus in Trichomonas vaginalis positive clinical samples from the Netherlands

Trichomonas vaginalis is the most common sexually transmitted parasitical infection worldwide. T. vaginalis can carry a virus: Trichomonas vaginalis virus (TVV). To date, four TVV species have been described. Few studies have investigated TVV prevalence and its clinical importance. We have developed a nested reverse-transcriptase PCR, with novel, type specific primers to directly detect TVV RNA in T. vaginalis positive clinical samples. A total of 119T. vaginalis positive clinical samples were collected in Amsterdam and "s-Hertogenbosch, the Netherlands, from 2012 to 2016. For all samples T. vaginalis was genotyped using multi-locus sequence typing. The T. vaginalis positive samples segregated into a two-genotype population: type I (n=64) and type II (n=55). All were tested for TVV with the new TVV PCR. We detected 3 of the 4 TVV species. Sequencing of the amplified products showed high homology with published TVV genomes (82-100%). Half of the T. vaginalis clinical samples (n=60, 50.4%) were infected with one or more TVV species, with a preponderance for TVV infections in T. vaginalis type I (n=44, 73.3%). Clinical data was available for a subset of samples (n=34) and we observed an association between testing positive for (any) TVV and reporting urogenital symptoms (p=0.023). The nested RT-PCR allowed for direct detection of TVV in T. vaginalis positive clinical samples. This may be helpful in studies and clinical settings, since T. vaginalis disease and/or treatment outcome may be influenced by the protozoa"s virus.

Unique Trichomonas vaginalis gene sequences identified in multinational regions of Northwest China

Trichomonas vaginalis (T. vaginalis) is a flagellated protozoan parasite that infects humans worldwide. This study determined the sequence of the 18S ribosomal RNA gene of T. vaginalis infecting both females and males in Xinjiang, China. Samples from 73 females and 28 males were collected and confirmed for infection with T. vaginalis, a total of 110 sequences were identified when the T. vaginalis 18S ribosomal RNA gene was sequenced. These sequences were used to prepare a phylogenetic network. The rooted network comprised three large clades and several independent branches. Most of the Xinjiang sequences were in one group. Preliminary results suggest that Xinjiang T. vaginalis isolates might be genetically unique, as indicated by the sequence of their 18S ribosomal RNA gene. Low migration rate of local people in this province may contribute to a genetic conservativeness of T. vaginalis. The unique genetic feature of our isolates may suggest a different clinical presentation of trichomoniasis, including metronidazole susceptibility, T. vaginalis virus or Mycoplasma co-infection characteristics. The transmission and evolution of Xinjiang T. vaginalis is of interest and should be studied further. More attention should be given to T. vaginalis infection in both females and males in Xinjiang.

Multilocus sequence typing of Trichomonas vaginalis clinical samples from Amsterdam, the Netherlands

OBJECTIVES

In this cross-sectional epidemiological study we aimed to identify molecular profiles for Trichomonas vaginalis and to determine how these molecular profiles were related to patient demographic and clinical characteristics.

SETTING

Molecular typing methods previously identified two genetically distinct subpopulations for T. vaginalis; however, few molecular epidemiological studies have been performed. We now increased the sensitivity of a previously described multilocus sequence typing (MLST) tool for T. vaginalis by using nested PCR. This enabled the typing of direct patient samples.

PARTICIPANTS

From January to December 2014, we collected all T. vaginalis positive samples as detected by routine laboratory testing. Samples from patients either came from general practitioners offices or from the sexually transmitted infections (STI) clinic in Amsterdam. Epidemiological data for the STI clinic patients were retrieved from electronic patient files.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the success rate of genotyping direct T. vaginalis positive samples. The secondary outcome was the relation between T. vaginalis genotypes and risk factors for STI.

RESULTS

All 7 MLST loci were successfully typed for 71/87 clinical samples. The 71 typed samples came from 69 patients, the majority of whom were women (n=62; 90%) and half (n=34; 49%) were STI clinic patients. Samples segregated into a two population structure for T. vaginalis representing genotypes I and II. Genotype I was most common (n=40; 59.7%). STI clinic patients infected with genotype II reported more sexual partners in the preceding 6 months than patients infected with genotype I (p=0.028). No other associations for gender, age, ethnicity, urogenital discharge or co-occurring STIs with T. vaginalis genotype were found.

CONCLUSIONS

MLST with nested PCR is a sensitive typing method that allows typing of direct (uncultured) patient material. Genotype II is possibly more prevalent in high-risk sexual networks.