Gynaecological infections as risk determinants of subsequent cervical neoplasia

A quantitative resazurin assay to determinate the viability of Trichomonas vaginalis and the cytotoxicity of organic solvents and surfactant agents

Trichomonas vaginalis causes trichomonosis, the most common, non-viral sexually transmitted disease. To test anti-Trichomonas agents, usually many with low water solubility, organic solvents and surfactant agents should be used. Therefore, the minimal inhibitory concentration (MIC) of acetone, methanol, ethanol, isopropanol, DMSO, Tween 20, Tween 80, and Triton X-100 was determined against T. vaginalis isolates using the quantitative resazurin method. Our results showed that solvents and surfactant agents can be employed as vehicles to test bioactive compounds at lower concentrations than MIC values and we suggest acetone and DMSO as preferential. Moreover, a new methodology is established to substitute or to complement the counting of viable trophozoites. The amount of resazurin reduced by T. vaginalis can be quantified by fluorescence spectroscopy, making the test a quantitative determination of cell viability. These results contribute for pharmacological investigations of bioactive compounds that need the use of solvents as solubilization vehicles to test anti-Trichomonas activity.

Glyceraldehyde-3-phosphate dehydrogenase is a surface-associated, fibronectin-binding protein of Trichomonas vaginalis

Trichomonas vaginalis colonizes the urogenital tract of humans and causes trichomonosis, the most prevalent nonviral sexually transmitted disease. We have shown an association of T. vaginalis with basement membrane extracellular matrix components, a property which we hypothesize is important for colonization and persistence. In this study, we identify a fibronectin (FN)-binding protein of T. vaginalis. A monoclonal antibody (MAb) from a library of hybridomas that inhibited the binding of T. vaginalis organisms to immobilized FN was identified. The MAb (called ws1) recognized a 39-kDa protein and was used to screen a cDNA expression library of T. vaginalis. A 1,086-bp reactive cDNA clone that encoded a protein of 362 amino acids with identity to glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was obtained. The gapdh gene was cloned, and recombinant GAPDH (rGAPDH) was expressed in Escherichia coli cells. Natural GAPDH and rGAPDH bound to immobilized FN and to plasminogen and collagen but not to laminin. MAb ws1 inhibited binding to FN. GAPDH was detected on the surface of trichomonads and was upregulated in synthesis and surface expression by iron. Higher levels of binding to FN were seen for organisms grown in iron-replete medium than for organisms grown in iron-depleted medium. In addition, decreased synthesis of GAPDH by antisense transfection of T. vaginalis gave lower levels of organisms bound to FN and had no adverse effect on growth kinetics. Finally, GAPDH did not associate with immortalized vaginal epithelial cells (VECs), and neither GAPDH nor MAb ws1 inhibited the adherence of trichomonads to VECs. These results indicate that GAPDH is a surface-associated protein of T. vaginalis with alternative functions.

Genetic identity and differential gene expression between Trichomonas vaginalis and Trichomonas tenax

BACKGROUND

Trichomonas vaginalis is a human urogenital pathogen responsible for trichomonosis, the number-one, non-viral sexually transmitted disease (STD) worldwide, while T. tenax is a commensal of the human oral cavity, found particularly in patients with poor oral hygiene and advanced periodontal disease. The extent of genetic identity between T. vaginalis and its oral commensal counterpart is unknown.

RESULTS

Genes that were differentially expressed in T. vaginalis were identified by screening three independent subtraction cDNA libraries enriched for T. vaginalis genes. The same thirty randomly selected cDNA clones encoding for proteins with specific functions associated with colonization were identified from each of the subtraction cDNA libraries. In addition, a T. vaginalis cDNA expression library was screened with patient sera that was first pre-adsorbed with an extract of T. tenax antigens, and seven specific cDNA clones were identified from this cDNA library. Interestingly, some of the clones identified by the subtraction cDNA screening were also obtained from the cDNA expression library with the pre-adsorbed sera. Moreover and noteworthy, clones identified by both the procedures were found to be up-regulated in expression in T. vaginalis upon contact with vaginal epithelial cells, suggesting a role for these gene products in host colonization. Semi-quantitative RT-PCR analysis of select clones showed that the genes were not unique to T. vaginalis and that these genes were also present in T. tenax, albeit at very low levels of expression.

CONCLUSION

These results suggest that T. vaginalis and T. tenax have remarkable genetic identity and that T. vaginalis has higher levels of gene expression when compared to that of T. tenax. The data may suggest that T. tenax could be a variant of T. vaginalis.

Perinatal mortality and other severe adverse pregnancy outcomes associated with treatment of cervical intraepithelial neoplasia: meta-analysis

OBJECTIVE

To assess the relative risk of perinatal mortality, severe preterm delivery, and low birth weight associated with previous treatment for precursors of cervical cancer.

DATA SOURCES

Medline and Embase citation tracking from January 1960 to December 2007. Selection criteria Eligible studies had data on severe pregnancy outcomes for women with and without previous treatment for cervical intraepithelial neoplasia. Considered outcomes were perinatal mortality, severe preterm delivery (<32/34 weeks), extreme preterm delivery (<28/30 weeks), and low birth weight (<2000 g, <1500 g, and <1000 g). Excisional and ablative treatment procedures were distinguished.

RESULTS

One prospective cohort and 19 retrospective studies were retrieved. Cold knife conisation was associated with a significantly increased risk of perinatal mortality (relative risk 2.87, 95% confidence interval 1.42 to 5.81) and a significantly higher risk of severe preterm delivery (2.78, 1.72 to 4.51), extreme preterm delivery (5.33, 1.63 to 17.40), and low birth weight of <2000 g (2.86, 1.37 to 5.97). Laser conisation, described in only one study, was also followed by a significantly increased chance of low birth weight of <2000 g and <1500 g. Large loop excision of the transformation zone and ablative treatment with cryotherapy or laser were not associated with a significantly increased risk of serious adverse pregnancy outcomes. Ablation by radical diathermy was associated with a significantly higher frequency of perinatal mortality, severe and extreme preterm delivery, and low birth weight below 2000 g or 1500 g.

CONCLUSIONS

In the treatment of cervical intraepithelial neoplasia, cold knife conisation and probably both laser conisation and radical diathermy are associated with an increased risk of subsequent perinatal mortality and other serious pregnancy outcomes, unlike laser ablation and cryotherapy. Large loop excision of the transformation zone cannot be considered as completely free of adverse outcomes.

Galectin-1 on cervical epithelial cells is a receptor for the sexually transmitted human parasite Trichomonas vaginalis

The extracellular protozoan parasite Trichomonas vaginalis causes the most prevalent non-viral sexually transmitted human infection, yet the pathogenesis of infection is poorly understood, and host cell receptors have not been described. The surface of T. vaginalis is covered with a glycoconjugate called lipophosphoglycan (LPG), which plays a role in the adherence and cytotoxicity of parasites to human cells. T. vaginalis LPG contains high amounts of galactose, making this polysaccharide a candidate for recognition by the galactose-binding galectin family of lectins. Here we show that galectin-1 (gal-1) is expressed by human cervical epithelial cells and binds T. vaginalis LPG. Gal-1 binds to parasites in a carbohydrate-dependent manner that is inhibited in the presence of T. vaginalis LPG. Addition of purified gal-1 to cervical epithelial cells also enhances parasite binding, while a decrease in gal-1 expression by small interfering RNA (siRNA) transfection decreases parasite binding. In contrast, the related galectin-7 (gal-7) does not bind T. vaginalis in a carbohydrate-dependent manner, and is unable to mediate attachment of parasites to host cells. Our data are consistent with the presence of multiple host cell receptors for T. vaginalis of which gal-1 is the first to be identified and highlight the importance of glycoconjugates in host-pathogen interactions.

Global epidemiology and control of Trichomonas vaginalis

PURPOSE OF REVIEW

Trichomonas vaginalis is the most common curable sexually transmitted infection. Despite a number of serious health consequences including facilitation of HIV transmission, pelvic inflammatory disease and adverse outcomes of pregnancy it remains an under-recognized condition. This review aims to update the reader on the global epidemiology and control of T. vaginalis.

RECENT FINDINGS

The burden of T. vaginalis infection is found in resource-limited settings and high-risk groups in industrialized settings. Utilization of polymerase chain reaction-based diagnostics has enhanced our understanding of the epidemiology of T. vaginalis both at the population level and in sexual partners. High rates of asymptomatic infection in male partners of infected females and subsequent re-infection have significant implications for control programmes. Further studies investigating the role of T. vaginalis in facilitating HIV transmission has highlighted its significance and the need to develop and implement control interventions.

SUMMARY

Future research to develop cheap, point-of-care diagnostic tests will allow a greater understanding of T. vaginalis epidemiology. In addition, the effect of treatment on outcome of pregnancy and HIV acquisition requires further study. This will in turn facilitate operational studies evaluating optimal control strategies and their impact on the complications of T. vaginalis.

Application of two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for proteomic analysis of the sexually transmitted parasite Trichomonas vaginalis

Trichomonas vaginalis is a sexually transmitted protozoan parasite that infects the human urogenital tract causing trichomoniasis, a worldwide disease. In this work, a fresh clinical isolate of T. vaginalis was used for study of the protein expression in this species. Two-dimensional gel electrophoresis (2-DE) and MALDI-TOF/TOF mass spectrometry (MS) were employed to create a reference map of soluble proteins in the pH range 4-7. A set of 116 proteins belonging to functional classes expressed in high and low abundance was identified by peptide mass fingerprinting and tandem MS. These identifications corresponded to 67 different proteins, suggesting that post-translational modifications are common phenomena in T. vaginalis. Identified proteins were classified into 16 groups according to biological processes. Among detected proteins we identified the major enzymes involved in both cytosolic and hydrogenosomal metabolic pathways, as well as putative protein targets for new drug design. In addition, this analysis allows validation of previous gene predictions confirming the expression of 15 hypothetical proteins. Finally, the findings here reported represent the first reference proteome map of T. vaginalis and the first steps towards the description of a comprehensive proteome map of this parasite.

Negative iron regulation of the CP65 cysteine proteinase cytotoxicity in Trichomonas vaginalis

Several cysteine proteinases (CPs) participate in the virulence of Trichomonas vaginalis. One of them is a 65kDa CP, CP65, involved in cytotoxicity. The aim of this work was to investigate the effect of iron on the trichomonal CP65-dependent cytotoxicity using parasites grown under distinct iron concentrations. Cytotoxicity and cell-binding assays, and zymograms were performed. At the highest iron concentration (250 microM), parasites exhibited the lowest levels of cytotoxicity and less CP65 proteolytic activity. Other cations in the culture medium did not affect the trichomonal CP65-dependent cytotoxicity as iron did. Another four trichomonad fresh isolates presented similar iron negative effect over cytotoxicity. Western blot and RT-PCR experiments also showed reduction in the amount of protein and transcript of CP65 in trichomonads grown under iron-rich conditions, as compared with parasites grown in normal and iron-depleted media. Indirect immunofluorescence using the anti-CP65 antibody showed that parasites grown in iron-rich medium expressed less CP65 than those grown in normal and iron-depleted media. Cytotoxicity inhibition experiments with the anti-CP65 antibody confirmed the iron negative effect over the CP65-dependent cytotoxicity. In conclusion, our data show that iron specifically down-regulates proteolytic activity, expression, and transcription of CP65, negatively affecting trichomonal cytotoxicity in vitro.

Prevalence of cervical neoplastic lesions and Human Papilloma Virus infection in Egypt: National Cervical Cancer Screening Project

Background

Data from Egyptian studies provide widely varying estimates on the prevalence of pre-malignant and malignant cervical abnormalities and human papilloma virus (HPVs) infection. To define the prevalence and risk factors of pre-invasive and invasive cervical cancer (cacx), a community based full-scale cross sectional, household survey including 5453 women aged between 35 and 60 years was conducted.

Methods

The study period was between February 2000 and December 2002. Initially, conventional Papanicolaou (Pap) smears were evaluated using the Bethesda system (TBS), followed by colposcopic guided biopsy (CGB) for all epithelial abnormalities (EA). In a third step, HPV was tested on all EA by in-situ hybridization (ISH) using first the broad spectrum HPV probe recognizing HPVs 6, 11, 16, 18, 30, 31, 35, 45, 51 and 52 followed by subtyping with probes 6/11, 16/18 and 31/33. Lastly, unequivocal cases were immunostained for herpes simplex type-2 (HSV-2), cytomegalovirus (CMV), and human immunodeficiency virus (HIV).

Results

EA representing 7.8% (424/5453), were categorized into atypical squamous cell of undetermined significance (ASCUS) (34.4%), atypical glandular cell of undetermined significance (AGCUS) (15.3%), combined ASCUS and AGCUS (3.1%), low grade squamous intraepithelial lesions (SIL) (41.0%), high grade SIL (5.2%) and invasive lesions (1%). CGB of EA (n = 281) showed non neoplastic lesions (12.8%), atypical squamous metaplasia (ASM) (19.2%), cervical intraepithelial neoplasia I (CIN) (44.4%), CIN II (4.4%), CINIII (2.8%), endocervical lesions (5.2%), combined squamous and endocervical lesions (10.0%), invasive squamous cell carcinoma (SCC) (0.02%) and extranodal marginal zone B cell lymphoma (MZBCL) (0.02%). The overall predictive value of cytology was 87% while the predictive value for high grade lesions was 80%. On histological basis, HPVs were present in 94.3% of squamous lesions while it was difficult to be identified in endocervical ones. ISH revealed positivity for pan HPV in 65.9% of the studied biopsies (n = 217), with incorporation of the viral genome HPV 6/11, 16/18 and 31/33 in 11.1%, 33.3% and 17.1% respectively. Multiple HPVs infections were identified in 0.02%.

Conclusion

Pre-invasive high grade lesions and invasive cervical carcinoma represent 0.5% and 0.04% respectively in Egyptian women. HPV mostly 16/18 as a risk factor (p < 0.001), was frequently associated with mixed infections (p < 0.001) and bilharzial infestation (p < 0.001).

Antisense RNA decreases AP33 gene expression and cytoadherence by T. vaginalis

BACKGROUND

Host parasitism by Trichomonas vaginalis is complex. Adherence to vaginal epithelial cells (VECs) is mediated by surface proteins. We showed before that antisense down-regulation of expression of adhesin AP65 decreased amounts of protein, which lowered levels of T. vaginalis adherence to VECs. We now perform antisense down-regulation of expression of the ap33 gene to evaluate and confirm a role for AP33 in adherence by T. vaginalis. We also used an established transfection system for heterologous expression of AP33 in T. foetus as an additional confirmatory approach.

RESULTS

We successfully select stable trichomonads with sense (S) and antisense (AS) plasmids. RT-PCR confirmed decreased amounts of ap33 mRNA in AS-transfected parasites, and decreased amounts of AP33 had no effect on growth and viability when compared to wild-type (wt) trichomonads. Immunoblots of proteins from AS-transfectants gave significant decreased amounts of functional AP33 capable of binding to host cells compared to wt- and S-transfected trichomonads. As expected, AS-transfectants had lower levels of adherence to VECs, which was related to reduction in surface expression of AP33. Stable expression of T. vaginalis AP33::HA fusion in T. foetus was confirmed by immunoblots and fluorescence. The episomally-expressed surface AP33::HA fusion increased adherence of trichomonads to human VECs, which was abrogated with anti-AP33 serum.

CONCLUSION

These results using both antisense inhibition of gene expression and AP33 synthesis and the heterologous expression of AP33 in T. foetus confirms a role for this protein as an adhesin in T. vaginalis.

The proteins secreted by Trichomonas vaginalis and vaginal epithelial cell response to secreted and episomally expressed AP65

We showed recently that contact of human vaginal epithelial cells (VECs) by Trichomonas vaginalis and incubation with trichomonad proteins in conditioned medium induced expression of VEC genes. We performed 2-D SDS-PAGE followed by MALDI-TOF to identify the major secreted proteins. Based on protein abundance and separation of spots in 2-D gels, 32 major secreted proteins were examined, which gave 19 proteins with accession numbers. These proteins included known secreted cysteine proteinases. In addition, other secreted proteins were enzymes of carbohydrate metabolism, adhesin protein AP65, heat shock proteins, thioredoxin reductase and coronins. We confirmed that the secreted trichomonad proteins induced expression of VEC genes, including interleukin 8 (IL-8), COX-2 and fibronectin. Purified AP65 added to VECs had a pronounced effect only on IL-8 gene expression, which was inhibited in the presence of 12G4 monoclonal antibody to AP65. Moreover, AP65 expressed episomally within epithelial cells was found to enhance the expression of IL-8 and COX-2. This may be the first report of analysis of the secreted proteins of T. vaginalis and of the host epithelial cell response to these proteins and to the prominent adhesin AP65.

Trichomonas vaginalis lipophosphoglycan triggers a selective upregulation of cytokines by human female reproductive tract epithelial cells

Trichomonas vaginalis is one of the most common nonviral sexually transmitted human infections and, worldwide, has been linked to increased incidence of human immunodeficiency virus type 1 transmission, preterm delivery, low birth weight, cervical cancer, and vaginitis. The molecular pathways that are important in initiating host inflammatory and immune responses to T. vaginalis are poorly understood. Here we report interactions of human cervicovaginal epithelial cells with the most abundant cell surface glycoconjugate of the parasite, the T. vaginalis lipophosphoglycan (LPG). Purified LPG mediated the adhesion of parasites to human vaginal epithelial cells in a dose-dependent manner. Furthermore, T. vaginalis LPG (but not LPG from Tritrichomonas foetus, the causative agent of bovine trichomoniasis) induced a selective upregulation of chemotactic cytokines by human endocervical, ectocervical, and vaginal epithelial cells, which do not express Toll-like receptor 4/MD2. The T. vaginalis LPG triggered interleukin 8 (IL-8), which promotes the adhesion and transmigration of neutrophils across the endothelium, and macrophage inflammatory protein 3alpha, which is a chemoattractant for immune cells and is essential for dendritic cell maturation. These effects were dose dependent and sustained in the absence of cytotoxicity and IL-1beta release and utilized, at least in part, a signaling pathway independent from the Toll-like/IL-1 receptor adaptor protein MyD88.

Location of the cell-binding domain of CP65, a 65kDa cysteine proteinase involved in Trichomonas vaginalis cytotoxicity

The cysteine proteinase (CP) of 65kDa, CP65, binds to the surface of HeLa cells and is involved in Trichomonas vaginalis cellular damage. To identify and locate the CP65 cellular-binding domain, we enriched the CP65 protein band by ammonium sulfate fractionation and ion-exchange chromatography and the N-terminal sequence was obtained. A 618bp gene fragment was obtained by PCR using genomic DNA as template and primers derived from the N-terminal sequence of CP65 and the Asn papain-catalytic conserved region. This gene fragment encodes for 206 amino acid (aa) residues corresponding to the N-terminal region of a mature CP with 67-76% identity to the reported trichomonad cathepsin-L-like CPs. This gene fragment was expressed in a bacterial system for antibody production and functional analysis. Antibodies against the native trichomonad CP65 recognized the recombinant protein, referred to as rCP65, confirming its relationship with the CP65 gene. The rCP65 protein was bound to the surface of HeLa cells and competed with the native CP65 for binding. Antibodies to the rCP65 (alpha-rCP65) reacted with the trichomonad CP65 located on the parasite surface, and inhibited trichomonal cytotoxicity in a concentration-dependent manner. These data strongly suggest that this gene fragment encodes for the putative cell-binding domain (CBD) of CP65 located at its N-terminal region.

Genotyping Trichomonas vaginalis

A genotyping method has been developed to distinguish each Trichomonas vaginalis isolate and has provided the first genome mapping studies of this protist with an estimated 180Mb genome. The technique was developed using high molecular weight DNA prepared from five laboratory isolates from Australia and USA and 20 clinical isolates from South Africa. Inhibition of the notorious T. vaginalis endogenous nucleases by addition of potent inhibitors was essential to the success of this study. Chromosomal DNA larger than 2.2Mb was macrorestricted to a minimum segment size of approximately 50kb, separated by pulsed field gel electrophoresis and hybridised with a variety of gene probes. Each isolate generated a unique pattern that was distinguished by each of the probes. Four single copy gene probes (fd, hmp35, ibp39 and pfoD) were identified but probes which identified several bands (pfoB and alpha-scs) per isolate were most informative for genotyping. The pyruvate:ferredoxin oxidoreductase B gene probe identified two to seven copies of pfoB (or its closely related homologue pfoA) per genome in different isolates and is an obvious candidate probe to identify epidemiological linkage between infections by this genotyping method. Cleavage of the genomes into smaller fragments failed to distinguish isolates from diverse locations indicating the proximal regions of genes are conserved.

Use of an adaptation of a commercially available PCR assay aimed at diagnosis of chlamydia and gonorrhea to detect Trichomonas vaginalis in urogenital specimens

Trichomonas vaginalis PCR using reagents from a commercially available assay for Chlamydia trachomatis and Neisseria gonorrhoeae was evaluated for detection of infection in women and men attending a sexually transmitted disease clinic. Evaluations included three primer sets, endocervical swabs, vaginal swabs and urine, and various storage conditions. The TVK3/TVK7 primer set was optimal in our hands with sensitivities ranging from 69.5 to 96.8%. In all comparisons, T. vaginalis PCR performed better than routine diagnostics using microscopy for women and culture for men (P > 0.05). The assay performed well for all sample types tested, and vaginal swabs were stable for up to 7 days at ambient temperature. Using samples prepared for, and reagents from, the C. trachomatis-N. gonorrhoeae PCR assay allowed incorporation of T. vaginalis PCR diagnosis into routine clinical testing.

A novel surface protein of Trichomonas vaginalis is regulated independently by low iron and contact with vaginal epithelial cells

BACKGROUND

Trichomonosis caused by Trichomonas vaginalis is the number one, non-viral sexually transmitted disease (STD) that affects more than 250 million people worldwide. Immunoglobulin A (IgA) has been implicated in resistance to mucosal infections by pathogens. No reports are available of IgA-reactive proteins and the role, if any, of this class of antibody in the control of this STD. The availability of an IgA monoclonal antibody (mAb) immunoreactive to trichomonads by whole cell (WC)-ELISA prompted us to characterize the IgA-reactive protein of T. vaginalis.

RESULTS

An IgA mAb called 6B8 was isolated from a library of mAbs reactive to surface proteins of T. vaginalis. The 6B8 mAb recognized a 44-kDa protein (TV44) by immunoblot analysis, and a full-length cDNA clone encoded a protein of 438 amino acids. Southern analysis revealed the gene (tv44) of T. vaginalis to be single copy. The tv44 gene was down-regulated at both the transcriptional and translational levels in iron-depleted trichomonads as well as in parasites after contact with immortalized MS-74 vaginal epithelial cells (VECs). Immunofluorescence on non-permeabilized organisms confirmed surface localization of TV44, and the intensity of fluorescence was reduced after parasite adherence to VECs. Lastly, an identical protein and gene were present in Tritrichomonas foetus and Trichomonas tenax.

CONCLUSION

This is the first report of a T. vaginalis gene (tv44) encoding a surface protein (TV44) reactive with an IgA mAb, and both gene and protein were conserved in human and bovine trichomonads. Further, TV44 is independently down-regulated in expression and surface placement by iron and contact with VECs. TV44 is another member of T. vaginalis genes that are regulated by at least two independent signaling mechanisms involving iron and contact with VECs.

Risk factors for HPV infection and cervical cancer among unscreened women in a high-risk rural area of China

We report a prevalence rate of 23.6% human papillomavirus (HPV) infection with oncogenic subtypes and 2.4% cervical intraepithelial neoplasia (CIN) III and cervical cancer (CC) in rural middle-aged women in 2 counties with the highest CC mortality in Shanxi Province, China. We examined the association of risk factors to HPV infection and to CIN III and CC in 8,798 unscreened women aged 35-50 years. Multivariate odds ratios (OR) and 95% confidence intervals (CI) for each endpoint were obtained for risk factors after adjustment for covariates. The OR of oncogenic HPV were: 1.41 (95% CI = 1.25-1.60) and 1.42 (95% CI = 1.24-1.61) for the participant and her husband having multiple sexual partners, respectively; 1.67 (95% CI = 1.37-2.04), 1.15 (95% CI = 1.04-1.26), and 0.82 (95% CI = 0.72-0.94) for ever (vs. never) diagnosed with tuberculosis, cervical inflammation and vaginal trichomoniasis, respectively; while bathing in a public (v. private) facility had an OR of 1.23 (95% CI =1.11-1.35). Seasonal fluctuations in HPV infection, but not CC, appeared in Xiangyuan County, with OR of 1.23 (95% CI = 1.14-1.33) and 1.51 (95% CI = 1.35-1.67) in Spring and Winter compared to Summer, respectively. The OR of CIN III and CC in the HPV positives were: 2.03 (95% CI = 1.63-2.53) for ages > or =45 years (vs. <40); and 4.01 (95% CI = 1.46-11.0) for > or =3 (vs. no) home births. Public health interventions and control strategies for improving the reproductive health of women in these rural populations need to be developed to reduce risk of HPV and subsequent CC.

Adherence to human vaginal epithelial cells signals for increased expression of Trichomonas vaginalis genes

Host parasitism by Trichomonas vaginalis is complex, and the adhesion to vaginal epithelial cells (VECs) by trichomonads is preparatory to colonization of the vagina. Since we showed increased synthesis of adhesins after contact with VECs (A. F. Garcia, et al., Mol. Microbiol. 47:1207-1224, 2003) and more recently demonstrated up-regulated gene expression in VECs after parasite attachment (A. S. Kucknoor, et al., Cell. Microbiol. 7:887-897, 2005), we hypothesized that enhanced expression of adhesin and other genes would result from signaling of trichomonads following adherence. In order to identify the genes that are up-regulated, we constructed a subtraction cDNA library enriched for differentially expressed genes from the parasites that were in contact with the host cells. Thirty randomly selected cDNA clones representing the differentially regulated genes upon initial contact of parasites with host cells were sequenced. Several genes encoded functional proteins with specific functions known to be associated with colonization, such as adherence, change in morphology, and gene transcription and translation. Interestingly, genes unique to trichomonads with unknown functions were also up-regulated. Semiquantitative reverse transcription-PCR (RT-PCR) confirmed expression of select genes. An increased amount of protein was demonstrated by immunoblotting with monoclonal antibody. Finally, we showed the transcriptional regulation of some genes by iron by using RT-PCR. To our knowledge, this is the first report addressing the differential regulation of T. vaginalis genes immediately upon contact with VECs.

Association of Chlamydia trachomatis with persistence of high-risk types of human papillomavirus in a cohort of female adolescents

Human papillomavirus (HPV) infection is a necessary but not sufficient cause of cervical cancer. While chlamydia infection has been associated with cervical cancer, the meaning of this association remains unclear. The authors' objective was to investigate this association by evaluating whether concurrent genital tract infections are associated with HPV persistence, a precursor to cervical cancer. Interview data and biologic samples for HPV, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and bacterial vaginosis testing were collected from female adolescents in an Atlanta, Georgia, longitudinal cohort study at 6-month visits (1999-2003). Associations with persistence (detection of the same HPV type at two sequential visits (visit pair)) were assessed among subjects with 2-5 visits and > or =6 months of follow-up. Associations were evaluated by logistic regression using methods for correlated data. Type-specific persistence of high-risk HPV types was detected in 77 of 181 (43%) analyzed visit pairs. Concurrent infection with C. trachomatis was independently associated with persistence of high-risk HPV types (adjusted odds ratio = 2.1, 95% confidence interval: 1.0, 4.1). Infection with more than one HPV type at the initial visit was also associated with high-risk persistence (adjusted odds ratio = 2.8, 95% confidence interval: 1.6, 4.9). The association between chlamydia infection and cervical cancer may be due to an effect of chlamydia infection on persistence of high-risk HPV.

Heterogeneity in extracellular nucleotide hydrolysis among clinical isolates of Trichomonas vaginalis

Trichomonas vaginalis is a parasitic protozoan that causes trichomonosis, a sexually-transmitted disease, with serious sequelae to women and men. As the host-parasite relationship is complex, it is important to investigate biochemical aspects of the parasite that contribute to our understanding of trichomonal biology and pathogenesis. Nucleoside triphosphate diphosphohydrolase 1 (NTPDase 1), which hydrolyses extracellular ATP and ADP, and ecto-5'-nucleotidase, which hyrolyses AMP, have been characterized in laboratory isolates of T. vaginalis. Here we show that the extracellular ATP: ADP hydrolysis ratio varies among fresh clinical isolates, which presented higher ATPase and ADPase activities than long-term-grown isolates. Growth of parasites in iron-replete and iron-depleted medium resulted in different, albeit minor, patterns in extracellular ATP and ADP hydrolysis among isolates. Importantly, some isolates had low or absent ecto-5'-nucleotidase activity, regardless of environmental conditions tested. For isolates with ecto-5'-nucleotidase activity, high- and low-iron trichomonads had increased and decreased levels of activity, respectively, compared to organisms grown in normal TYM-serum medium. This suggests a regulation in expression of either the enzyme amounts and/or activity under the control of iron. Finally, we found no correlation between the presence or absence of dsRNA virus infection among trichomonad isolates and NTPDase and ecto-5'-nucleotidase activities.

What's new in bacterial vaginosis and trichomoniasis?

The use of biochemical profiles and new molecular microbiologic methodologies is transforming our understanding of BV. Most important is the recognition of different subgroups of women who have BV who are at variable risk of certain obstetric and gynecologic complications. New diagnostic tests may soon be available that will allow women to test self-obtained specimens. Treatment of BV has lagged, although innovative methods appear to be helpful in managing recurrent diseases.

Trichomonas vaginalis adherence mediates differential gene expression in human vaginal epithelial cells

Trichomonas vaginalis, an ancient protist, colonizes the vaginal mucosa causing trichomonosis, a vaginitis that sometimes leads to severe health complications. Preparatory to colonization of the vagina is the adhesion to vaginal epithelial cells (VECs) by trichomonads. We hypothesized that VECs alter the gene expression to form a complex signalling cascade in response to trichomonal adherence. In order to identify the genes that are upregulated, we constructed a subtraction cDNA library after contact with parasites that is enriched for differentially expressed genes from the immortalized MS-74 VECs. Sixty cDNA clones were sequenced and to our knowledge for the first time, differentially regulated genes were identified in response to early trichomonal infection. The identified genes were found to encode functional proteins with specific functions associated with cell structure maintenance and extracellular matrix components, proinflammatory molecules and apoptosis. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) confirmed expression of selected genes. Further, cyclooxygenase 2 (COX-2) protein expression was analysed using Western blot and immunofluorescence assays. Data suggest that p38 mitogen-activated protein (MAP) kinase and tyrosine kinases play a role in COX-2 induction. Finally, T. vaginalis and Tritrichomonas foetus but not Pentatrichomonas hominis induce expression of COX-2. This is a first attempt at elucidating the basis of interaction of trichomonads with host cells and the corresponding host responses triggered by the parasites.

Use of an immunochromatographic assay for rapid detection of Trichomonas vaginalis in vaginal specimens

Trichomonas vaginalis infection is estimated to be the most widely prevalent nonviral sexually transmitted infection in the world. Wet-mount microscopy is the most common diagnostic method, although it is less sensitive than culture. The OSOM Trichomonas Rapid Test (Genzyme Diagnostics, Cambridge, Mass.) (referred to here as OSOM) is a new point-of-care diagnostic assay for T. vaginalis that uses an immunochromatographic capillary flow (dipstick) assay and provides results in 10 min. The purpose of this study was to determine the test characteristics of OSOM compared to those of a composite reference standard (CRS) comprised of wet-mount microscopy and T. vaginalis culture. This multicenter cross-sectional study enrolled sexually active women > or =18 years of age who presented with symptoms of vaginitis, exposure to T. vaginalis, or multiple sexual partners. Vaginal-swab specimens were obtained for T. vaginalis culture, wet mount, and rapid testing. The prevalence of T. vaginalis in this sample was 23.4% (105 of 449) by the CRS. The sensitivity and specificity of OSOM vaginal-swab specimens were 83.3 and 98.8%, respectively, while wet mount had a sensitivity and specificity of 71.4 and 100%, respectively, compared to the CRS. OSOM performed significantly better than wet mount (P = 0.004) and detected T. vaginalis in samples that required 48 to 72 h of incubation prior to becoming culture positive. The performance of the rapid test was not affected by the presence of coinfections with chlamydia and gonorrhea. The OSOM Trichomonas Rapid Test is a simple, objective test that can be expected to improve the diagnosis of T. vaginalis, especially where microscopy and culture are unavailable.

Trichomonas vaginalis polyamine metabolism is linked to host cell adherence and cytotoxicity

Trichomonas vaginalis secretes putrescine that is readily detected in vaginal secretions. We wanted to examine the effect of decreased putrescine synthesis by inhibition of ornithine decarboxylase (ODC) on T. vaginalis. One reason is because inhibition of Tritrichomonas foetus ODC results in growth arrest, destruction of hydrogenosomes, and decreased amounts of hydrogenosomal enzymes. Treatment of T. vaginalis T016 with >/=20 mM 1,4-diamino-2-butanone (DAB) to inhibit ODC resulted in growth arrest, which was reversed by addition of exogenous putrescine. No similar reversal of growth arrest was achieved with the polyamines spermine or spermidine or with iron. Electron microscopic examination of control versus DAB-treated trichomonads did not reveal any adverse effects on the number and integrity of hydrogenosomes. Further, the adhesins AP65, AP51, and AP33 mediating binding to immortalized vaginal epithelial cells (VECs) share identity to enzymes of the hydrogenosome organelle, and there was no difference in amounts of adhesins between control versus DAB-treated T. vaginalis parasites. Likewise, similar patterns and extent of fluorescence were evident for the prominent AP65 adhesin. Surprisingly, DAB treatment increased by 4- to 20-fold above untreated trichomonads handled identically the level of adherence mediated by adhesins. Interestingly, the enhanced attachment to VECs was reversed by exogenous putrescine added to DAB-treated trichomonads. Equally noteworthy was that DAB-treated T. vaginalis with enhanced adherence did not possess the previously reported ability to kill host cells in a contact-dependent fashion mediated by cysteine proteinases, and total cysteine proteinase activity patterns were identical between control and DAB-treated trichomonads. Overall, these data suggest that polyamine metabolism and secreted putrescine are linked to host cell adherence and cytotoxicity.

Heterologous expression in Tritrichomonas foetus of functional Trichomonas vaginalis AP65 adhesin

Background

Trichomonosis, caused by Trichomonas vaginalis, is the number one, nonviral sexually transmitted infection that has adverse consequences for the health of women and children. The interaction of T. vaginalis with vaginal epithelial cells (VECs), a step preparatory to infection, is mediated in part by the prominent surface protein AP65. The bovine trichomonad, Tritrichomonas foetus, adheres poorly to human VECs. Thus, we established a transfection system for heterologous expression of the T. vaginalis AP65 in T. foetus, as an alternative approach to confirm adhesin function for this virulence factor.

Results

In this study, we show stable transfection and expression of the T. vaginalis ap65 gene in T. foetus from an episomal pBS-ap65-neo plasmid. Expression of the gene and protein was confirmed by RT-PCR and immunoblots, respectively. AP65 in transformed T. foetus bound to host cells. Specific mAbs revealed episomally-expressed AP65 targeted to the parasite surface and hydrogenosome organelles. Importantly, surface-expression of AP65 in T. foetus paralleled increased levels of adherence of transfected bovine trichomonads to human VECs.

Conclusion

The T. vaginalis AP65 adhesin was stably expressed in T. foetus, and the data obtained using this heterologous system strongly supports the role of AP65 as a prominent adhesin for T. vaginalis. In addition, the heterologous expression in T. foetus of a T. vaginalis gene offers an important, new approach for confirming and characterizing virulence factors.

HeLa cell nucleus, a source of thymidine for Trichomonas vaginalis growing in vitro

Trichomonas vaginalis is a parasitic protist incapable of de novo purine and pyrimidine biosynthesis. The lack of these de novo syntheses of nucleotides is supplemented with purine and pyrimidine salvage pathways. Likewise, T. vaginalis is incapable of converting its ribonucleotides to deoxyribonucleotides. Therefore, the parasite must rely on the salvage of exogenous deoxyribonucleosides for DNA synthesis. It has been demonstrated that the parasite can incorporate external adenine and guanine in vitro, but no in vivo nucleotide source has been identified so far. Accordingly, we set out to determine if the parasite could incorporate 3H-thymidine from the nuclei of a cervical-derived cell line into its own DNA. By light and electron microscopy we found that the parasite was able to interact directly, both with mechanically isolated HeLa cell nuclei and with the nuclei released after the disruption of HeLa cell monolayers by the parasite. This study shows that T. vaginalis was capable of incorporating 3H-thymidine from labeled HeLa cells into its own DNA suggesting that the nuclei of this cervical cell line could be an in vivo source of nucleotides for T. vaginalis.

Silencing the ap65 gene reduces adherence to vaginal epithelial cells by Trichomonas vaginalis

Host parasitism by Trichomonas vaginalis is complex and in part mediated by adherence to vaginal epithelial cells (VECs). Four trichomonad surface proteins bind VECs as adhesins, and AP65 is a major adhesin with sequence identity to an enzyme of the hydrogenosome organelle that is involved in energy generation. In order to perform genetic analysis and assess the role of AP65 in T. vaginalis adherence, we silenced expression of ap65 using antisense RNA. The gene for ap65 was inserted into the vector pBS-neo in sense and antisense orientations to generate plasmids pBS-neoS (S) and pBS-neoAS (AS), respectively. Trichomonads were then transfected with S and AS plasmids for selection of stable transfectants using Geneticin, and the presence of plasmid in transfectants was confirmed by polymerase chain reaction of the neo gene. Reverse transcription polymerase chain reaction and Northern blot analysis showed decreased amounts of ap65 transcript in AS transfected parasites. Growth kinetics of the antisense-transfected and wild type organisms were similar, suggesting that silencing AP65 did not affect overall energy generation for growth. Immunoblot analysis using monoclonal antibody (mAb) to AP65 of AS transfectants showed decreased amounts of AP65 when compared to wild type or S transfectants. Not unexpectedly, this corresponded to decreased amounts of AP65 bound to VECs in a functional ligand assay. Reduction in parasite surface expression of AP65 was related to lower levels of adherence to VECs by AS-transfectants compared to control organisms. Antisense silencing of ap65 was not alleviated by growth of trichomonads in high iron, which up-regulates transcription of ap65. Our work reaffirms the role for AP65 as an adhesin, and in addition, we demonstrate antisense RNA gene silencing in T. vaginalis to study the contribution of specific genes in pathogenesis.

Trichomoniasis: under control or undercontrolled?

Aside from human papillomavirus, trichomoniasis is the most common sexually transmitted infection in the United States today, yet it has long been regarded as a sexually transmitted infection of minor importance. Medical opinion has traditionally held that it plays little role in health complications in women, and it is rarely seen in men. However, evidence has recently accumulated implicating Trichomonas vaginalis as a contributor to a variety of adverse outcomes among both sexes. Among both women and men, the association of T vaginalis with human immunodeficiency acquisition and transmission has been shown in multiple studies. Among women, trichomoniasis may play a role in development of cervical neoplasia, postoperative infections, and adverse pregnancy outcomes and as a factor in atypical pelvic inflammatory disease and infertility. Among men, trichomoniasis has emerged as a cause of nongonoccocal urethritis and as contributing to male factor infertility. As evidence continues to accumulate, the time has come to increase diagnostic efforts beyond traditional sexually transmitted disease clinic settings.

Atypical genital herpes: report of five cases

Manifestations of human genital herpes virus (HSV) infection are not limited to the typical cluster of genital lesions. Here we present 5 case histories suggestive to clinically atypical genital herpes (HSV detected with the polymerase chain reaction) collected in 2001 from a private outpatient clinic specializing in dermatological and venereal diseases. The clinical presentations included mucopurulent cervicitis, haemorrhagic cystitis, recurrent urethritis, and lower back pain.

Predictors of infection with Trichomonas vaginalis: a prospective study of low income African-American adolescent females

OBJECTIVES

To identify psychosocial predictors of Trichomonas vaginalis infection among low income African-American adolescent females living in a high risk urban area of the United States.

METHODS

Baseline plus 6 and 12 month follow up data collected as part of an HIV prevention intervention trial were utilised. The baseline sample consisted of 522 African-American females, 14-18 years of age. Recruitment sites were located in low income neighbourhoods of Birmingham, Alabama, characterised by high rates of unemployment, substance abuse, violence, teenage pregnancy, and sexually transmitted infections. Self administered vaginal swab specimens were cultured for T vaginalis. Baseline measures collected as part of a self administered survey and face to face interviews were used to predict subsequent infection with T vaginalis at any of the three assessment periods conducted over the span of 1 year.

RESULTS

At baseline, 12.9% were diagnosed with T vaginalis. At the 6 and 12 month follow ups, T vaginalis was diagnosed in 8.9% and 10.2%, respectively. The strongest multivariate predictor of T vaginalis infection was biologically confirmed marijuana use; those using marijuana were more than six times as likely to test positive for T vaginalis (adjusted odds ratio (AOR) = 6.2, p = 0.0003). Other multivariate predictors were reporting that typical sex partners were at least 5 years older (AOR = 2.6; p = 0.005), reporting sex with non-steady partners (AOR = 1.9; p = 0.02), and history of delinquency (AOR = 1.3; p = 0.02). The odds of testing positive increased by 31% for every one unit increase on a six item scale measure of delinquency.

CONCLUSIONS

Infection with T vaginalis was common and significant multivariate predictors comprised a constellation of problem behaviours, each of which are potentially amenable to behavioural intervention.

Biological variability in clinical isolates of Trichomonas vaginalis

Eighteen clinical isolates of Trichomonas vaginalis were obtained from women who attended health centers of the Government of Madrid. A total of 1,848 vaginal specimens recovered during the gynaecological examination were seeded in culture tubes containing liquid Diamond medium. Pathogenicity to mice was determined after intraperitoneal inoculation of mice by quantification of mortality and gross damage to abdominal organs. As could be expected, a broad variability was obtained, being some of the isolates more virulent than the reference strain. Regarding to metronidazole susceptibility, none resistant isolate was found but different degrees of susceptibility were determined.

TaqMan-based detection of Trichomonas vaginalis DNA from female genital specimens

A double-labeled fluorescent probe was designed and evaluated for detecting Trichomonas vaginalis DNA in a 5' nuclease (TaqMan) assay. The T. vaginalis-specific probe contains a 5'-fluorescein (5'-FAM) and a 3'-rhodamine (TAMRA) derivative. Female genital secretions were collected on Amplicor (Roche Molecular, Indianapolis, Ind.) swabs and by a transport system used for Chlamydia trachomatis and/or Neisseria gonorrhoeae DNA detection by PCR. Five hundred fifty-two female genital specimens, of which 248 (45%) were vaginal specimens and 304 (55%) were introital, were tested for both T. vaginalis DNA and viable microorganisms using the 5' nuclease assay and broth culture, respectively. Of these, 304 of 552 (55%) were also evaluated by direct microscopic examination for the characteristic motile organism. After resolving discrepancies, the comparisons produced an analytical sensitivity and specificity for the TaqMan-based PCR assay of 97.8 and 97.4%, respectively. As a result, DeltaRQ values (differences in fluorescence due to probe hybridization and resulting 5'-FAM cleavage from the specific PCR product) of > or =2.0 and < or =1.5 were established for T. vaginalis-positive and -negative cutoffs, respectively. DeltaRQ values between 1.5 and 2.0 were considered indeterminate. Overall findings revealed a high level of agreement between PCR and culture for detecting T. vaginalis. Potential benefits of the 5' nuclease assay include a greater sensitivity compared to direct microscopic examination and the ease of testing large numbers of clinical specimens in a significantly shorter turnaround time compared to culture.

Drug susceptibility testing of anaerobic protozoa

A simple technique for routine, reproducible global surveillance of the drug susceptibility status of the anaerobic protozoa Trichomonas, Entamoeba, and Giardia is described. Data collected using this technique can be readily compared among different laboratories and with previously reported data. The technique employs a commercially available sachet and bag system to generate a low-oxygen environment and log(2) drug dilutions in microtiter plates, which can be monitored without aerobic exposure, to assay drug-resistant laboratory lines and clinically resistant isolates. MICs (after 2 days) of 3.2 and 25 microM indicated metronidazole-sensitive and highly clinically resistant isolates of T. vaginalis in anaerobic assays, respectively. The aerobic MICs were 25 and >200 microM. MICs (1 day) of 12.5 to 25 microM were found for axenic lines of E. histolytica, and MICs for G. duodenalis (3 days) ranged from 6.3 microM for metronidazole-sensitive isolates to 50 microM for laboratory metronidazole-resistant lines. This technique should encourage more extensive monitoring of drug resistance in these organisms.

Drug targets and mechanisms of resistance in the anaerobic protozoa

The anaerobic protozoa Giardia duodenalis, Trichomonas vaginalis, and Entamoeba histolytica infect up to a billion people each year. G. duodenalis and E. histolytica are primarily pathogens of the intestinal tract, although E. histolytica can form abscesses and invade other organs, where it can be fatal if left untreated. T. vaginalis infection is a sexually transmitted infection causing vaginitis and acute inflammatory disease of the genital mucosa. T. vaginalis has also been reported in the urinary tract, fallopian tubes, and pelvis and can cause pneumonia, bronchitis, and oral lesions. Respiratory infections can be acquired perinatally. T. vaginalis infections have been associated with preterm delivery, low birth weight, and increased mortality as well as predisposing to human immunodeficiency virus infection, AIDS, and cervical cancer. All three organisms lack mitochondria and are susceptible to the nitroimidazole metronidazole because of similar low-redox-potential anaerobic metabolic pathways. Resistance to metronidazole and other drugs has been observed clinically and in the laboratory. Laboratory studies have identified the enzyme that activates metronidazole, pyruvate:ferredoxin oxidoreductase, to its nitroso form and distinct mechanisms of decreasing drug susceptibility that are induced in each organism. Although the nitroimidazoles have been the drug family of choice for treating the anaerobic protozoa, G. duodenalis is less susceptible to other antiparasitic drugs, such as furazolidone, albendazole, and quinacrine. Resistance has been demonstrated for each agent, and the mechanism of resistance has been investigated. Metronidazole resistance in T. vaginalis is well documented, and the principal mechanisms have been defined. Bypass metabolism, such as alternative oxidoreductases, have been discovered in both organisms. Aerobic versus anaerobic resistance in T. vaginalis is discussed. Mechanisms of metronidazole resistance in E. histolytica have recently been investigated using laboratory-induced resistant isolates. Instead of downregulation of the pyruvate:ferredoxin oxidoreductase and ferredoxin pathway as seen in G. duodenalis and T. vaginalis, E. histolytica induces oxidative stress mechanisms, including superoxide dismutase and peroxiredoxin. The review examines the value of investigating both clinical and laboratory-induced syngeneic drug-resistant isolates and dissection of the complementary data obtained. Comparison of resistance mechanisms in anaerobic bacteria and the parasitic protozoa is discussed as well as the value of studies of the epidemiology of resistance.