Genetic variance of Trichomonas vaginalis isolates by Southern hybridization

Genotypic Variation in Trichomonas vaginalis Detected in South African Pregnant Women

Background

Trichomonas vaginalis is the causative agent of trichomoniasis. The genetic characterisation of T. vaginalis isolates reveals significant genetic diversity in this organism. Data on the prevalence of different genotypes of T. vaginalis in South African populations is lacking. This study investigated the diversity of T. vaginalis in a pregnant population in South Africa.

Methods

In this study, 362 pregnant women from the King Edward VIII Hospital in Durban, South Africa, provided vaginal swabs to be tested for the presence of T. vaginalis. T. vaginalis was detected using the TaqMan assay using commercially available primers and probes specific for this protozoan (Pr04646256_s1). The actin gene from T. vaginalis was amplified with gene-specific primers. The actin amplicons were digested with HindII, MseI, and RsaI, and the banding patterns were compared across the three digests for assignment of genotypes. Phylogenetic analysis was conducted using MEGA.

Results

The prevalence of T. vaginalis in the study population was 12.9% (47/362). Genotype G was the most frequent genotype in our study population. Genotypes H and I were detected in one sample each. According to the multiple sequence alignments and phylogenetic analysis, a level of diversity was observed across and within genotypes. Four different single-nucleotide changes in the actin gene were detected. Sample TV358 (H genotype) contained a single amino acid substitution from glutamine to lysine. Sample TV184 (G genotype) contained a single amino acid substitution from glutamic acid to arginine. Sample TV357 (G genotype) contained two amino acid substitutions, arginine to leucine and glycine to aspartic acid.

Conclusion

Three different genotypes were observed in the pregnant population. Diversity was observed across and within genotypes. The observed diversity can be challenging for future vaccine design and development of antigen-based rapid diagnostic tests for trichomoniasis.

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.

Genetic Diversity of Trichomonas Vaginalis Clinical Isolates According to Restriction Fragment Length Polymorphism Analysis of the 60-kDa Proteinase Gene

INTRODUCCTION

Trichomonas vaginalis is a highly prevalent parasitic that causes the sexually transmitted disease trichomoniasis with some serious health complications. More understanding about genetic features of the parasite can be helpful in the study of the pathogenesis, epidemiology of the infection and drug susceptibility. For this end, we conducted analysis of a fragment (23 kDa) of the p60 of T. vaginalis gene.

MATERIAL AND METHODS

The restriction fragment length polymorphism (RFLP) methods was used.

RESULT AND DISCUSSION

RFLP analysis showed the difference between T. vaginalis isolates from symptomatic and asymptomatic patients, suggesting a relation between the genetic identity of the isolates and their clinical manifestations.

Genetic diversity in Trichomonas vaginalis

Recent advances in genetic characterisation of Trichomonas vaginalis isolates show that the extensive clinical variability in trichomoniasis and its disease sequelae are matched by significant genetic diversity in the organism itself, suggesting a connection between the genetic identity of isolates and their clinical manifestations. Indeed, a high degree of genetic heterogeneity in T vaginalis isolates has been observed using multiple genotyping techniques. A unique two-type population structure that is both local and global in distribution has been identified, and there is evidence of recombination within each group, although sexual recombination between the groups appears to be constrained. There is conflicting evidence in these studies for correlations between T vaginalis genetic identity and clinical presentation, metronidazole susceptibility, and the presence of T vaginalis virus, underscoring the need for adoption of a common standard for genotyping the parasite. Moving forward, microsatellite genotyping and multilocus sequence typing are the most robust techniques for future investigations of T vaginalis genotype-phenotype associations.

Genetic diversity of Trichomonas vaginalis clinical isolates determined by EcoRI restriction fragment length polymorphism of heat-shock protein 70 genes

Restriction fragment length polymorphism (RFLP) analysis using a multilocus heat-inducible cytoplasmic heat-shock protein 70 (Hsp70) hybridization probe with EcoRI-digested genomic DNA was used in molecular typing of 129 Trichomonas vaginalis isolates. Results indicate that Trichomonas organisms exhibit considerable polymorphism in their Hsp70 RFLP patterns. Analysis of seven American Type Culture Collection reference strains and 122 clinical isolates, including 84 isolates from Jackson, Mississippi, 18 isolates from Atlanta, Georgia, and 20 isolates from throughout the United States, showed 105 distinct Hsp70 RFLP pattern subtypes for Trichomonas. Phylogenetic analysis of the Hsp70 RFLP data showed that the T. vaginalis isolates were organized into two clonal lineages. These results illustrate the substantial genomic diversity present in T. vaginalis and indicate that a large number of genetically distinct Trichomonas isolates may be responsible for human trichomoniasis in the United States.

Genetic variability between Trichomonas vaginalis isolates and correlation with clinical presentation

The random amplified polymorphic DNA (RAPD) technique was used to determine genetic differences among isolates of Trichomonas vaginalis and these genetic data were correlated with patient records. A panel of 10 random primers was used to determine the type and extent of intraspecific polymorphism in 40 isolates of T. vaginalis. All primers detected DNA polymorphism among isolates. Numerical analysis of 124 RAPD amplified bands generated by these 10 primers were carried out with the unweighted pair group methods analysis (UPGMA) using Jaccard's Similarity Coefficient and data were used to construct a dendrogram. Four main groups can be distinguished by RAPD data, these groups coincide with four different patient categories (asymptomatic and symptomatic: light, moderate, and severe infection). These patients did not have any concomitant vaginal infection. Each of the four groups can be characterized by specific genetic markers, but a specific 490bp marker was found to be specific for all symptomatic isolates, not the asymptomatic isolates. This is the first description of a possible virulence marker for T. vaginalis. Further studies will be necessary to ascertain the importance and function of this genetic marker in clinical infection.