Trichomoniasis: Genotype and Phenotype Correlations in African American Women

Despite serious public health consequences, its widespread prevalence, rising drug resistance
and treatment failures, little has been done to study the role of T. vaginalis genotype in
transmission, virulence, occurrence of mixed infections, and the spread of drug resistance,
primarily due to the lack of suitable assays for rapid strain typing. Previously utilized
genotyping techniques for Trichomonas are inadequate due to problems with speed of analysis,
sensitivity, and reproducibility between different labs. Multilocus sequence typing (MLST)
combines speed, sensitivity, portability, accuracy, and reliability by determining nucleotide
sequence polymorphisms (SNPs) present in small DNA fragments (300-400 nt) that are amplified
by polymerase chain reaction (PCR) from a number (usually 6-7) of neutrally selected
housekeeping genes. MLST assigns an allele fragment number (AFN) for each unique SNP or
combination of SNPs present in a gene fragment and uses these to identify unique sequence
types (STs) based on the AFN combinations in the collection of all the genes analyzed. MLST
has been used extensively to study epidemiology, population structure, virulence and
evolution in pathogenic bacteria but only for fungi among eukaryotes, due to the difficulty
of interpreting MLST data in diploid organisms. However, T. vaginalis differs from other
eukaryotes, possessing a stable haploid set of six chromosomes, and the investigators have
developed an MLST genotyping system for T. vaginalis clinical isolates. The data (AFNs and
STs) generated for each T. vaginalis strain by the MLST scheme we develop will be deposited
in a freely accessible internet database. This MLST scheme will then be used to examine the
relationships between strain genotypes and the clinical, epidemiologic, and physiologic
manifestations of trichomoniasis.

Trichomoniasis is characterized by a wide spectrum of clinical presentation and disease
sequelae. This clinical variability is accompanied by a high degree of genetic diversity in
Trichomonas vaginalis clinical isolates as we originally demonstrated and others have
confirmed. The investigators hypothesize that correlations between genotype and clinical
presentation are true for trichomoniasis and that T. vaginalis isolates differ in their
capacity for clinical disease, severity, drug resistance, and disease sequelae. In support,
several studies (10-40 patients) show a statistically significant correlation between the
genetic relatedness of T. vaginalis isolates, using a random amplified polymorphic DNA (RAPD)
technique, with their clinical presentation. Correlations between disease severity in
trichomoniasis and in vitro phenotypic properties such as cytoadherence, cytotoxicity and
expression of cysteine proteinase 30 kilo-dalton (kDa) protein have also been reported.
Significant differences in cytoadherence to cell monolayers, differential protein expression,
phagocytosis of target cells, ability to exert cytotoxic damage on cultured cells, and
pathogenicity and mortality in mice have been demonstrated in T. vaginalis clinical isolates,
indicating the wide variation in virulence properties present in Trichomonas isolates. The
investigators have also demonstrated up to four-fold differences in secreted cysteine
protease activity between cultured T. vaginalis clinical isolates. The accumulated evidence
strongly supports a correlation between individual T. vaginalis strains and their capacity
for virulence.

For this specific study, at the initial enrollment/diagnosis visit the investigators will
collect T. vaginalis isolates accompanied by a detailed clinical assessment, epidemiological
information, and the results of in vitro testing of drug .resistance. This information will
allow the investigators to determine if particular strains or groups of strains (as
determined by MLST genotyping) are associated with asymptomatic infection, clinical severity,
patient race, treatment failures, drug resistance, mixed infections or sexual history using
univariate and multivariate analysis. This is significant because positive associations of
particular strains or groups of strains with these factors, as the investigators expect to
find, will necessitate changes in the way trichomoniasis is managed and treated with
reference to the strains identified. The investigators will also independently test these
variables for correlations with each other to identify variables or combinations of variables
which may be associated with clinical manifestations of trichomoniasis.

The information the investigators gather will also permit a better understanding of
trichomoniasis in many additional ways. The investigators will culture T. vaginalis at test
of cure (TOC) follow-up visits to genotype and determine their drug resistance in order to
distinguish potential treatment failures or conversion to drug resistance (same genotype as
original visit) from re-infection by another contact (different genotype). This is
particularly significant for HIV+ women as their Trichomonas vaginalis infections are more
difficult to cure and T. vaginalis may persist, undetectable by culture, only to re-emerge up
to six months later. Trichomonas vaginalis is detected at TOC visits at much higher rates (up
to 36 %) in HIV+ women than in HIV- women (8%) with most of these infections ascribed to
treatment failures. Recent reports describe persistent, undetected T. vaginalis infections
cultured 3 and 6 months after an initial negative TOC result in women who report no
intervening sexual contacts. This is significant as a correlation of strain genotype with
persistent infection will identify HIV+ individuals needing multiple TOC visits, use of more
sensitive diagnostic tests, and perhaps longer treatment courses.

Inclusion Criteria:

- Trichomonas infection

Exclusion Criteria:

- pregnancy