|
 
 |
| ORIGINAL ARTICLE |
|
| Year : 2016 | Volume
: 9
| Issue : 2 | Page : 80-86 |
|
The endosymbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis in Egyptian Women and its correlation with pathogenicity
Eman K El-Gayar1, Amira B Mokhtar1, Soha I Awad2, Rasha H Soliman1, Wael A Hassan3
1 Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
2 Department of Parasitology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
3 Department of Pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| Date of Submission | 30-Apr-2016 |
| Date of Acceptance | 19-Jun-2016 |
| Date of Web Publication | 25-Apr-2017 |
Correspondence Address:
Eman K El-Gayar
Department of Parasitology, Faculty of Medicine, Suez Canal University, Ismailia
Egypt
 Source of Support: None, Conflict of Interest: None  | Check |
DOI: 10.4103/1687-7942.205169
Background Trichomonas vaginalis is the etiological parasite of trichomoniasis. Endosymbiotic Mycoplasma hominis can exist in T. vaginalis populations. However, its consequences are not yet known. Recently, T. vaginalis isolates positive for M. hominis as proven by PCR had greater cytopathic effects on human vaginal epithelial cells and also on Madin–Darby canine kidney cells in vitro.
Objective This study aimed to detect the presence of M. hominis infecting Egyptian T. vaginalis isolates and to evaluate the pathogenicity of this association in vivo.
Patients and methods Forty-five symptomatic and asymptomatic T. vaginalis isolates were obtained from Suez Canal and General Hospitals, Ismailia city, Egypt. All isolates were axenically cultivated in Diamond’s TYM medium, followed by DNA extraction and PCR using primer pair targeting 16S rRNA gene to detect M. hominis-infected isolates. Positive M. hominis PCR products were subjected to sequencing analysis. All isolates were experimentally inoculated intravaginally in female albino mice to assess the pathogenicity of different isolates.
Results The detection rate of M. hominis-positive T. vaginalis isolates was 20% as determined with PCR. No statistically significant association was recorded between M. hominis-infected T. vaginalis among symptomatic and asymptomatic isolates. Experimental mice infection showed varying degrees of inflammation by the different isolates.
Conclusion To our knowledge, this study is the first report of T. vaginalis infection by M. hominis among Egyptian isolates and it was deduced that the association of M. hominis and T. vaginalis does not affect the clinical presentation of vaginal trichomoniasis and does not cause enhanced pathological changes in infected mice. Keywords: Mycoplasma hominis, pathogenicity, symbiosis, Trichomonas vaginalis
How to cite this article:
El-Gayar EK, Mokhtar AB, Awad SI, Soliman RH, Hassan WA. The endosymbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis in Egyptian Women and its correlation with pathogenicity. Parasitol United J 2016;9:80-6 |
How to cite this URL:
El-Gayar EK, Mokhtar AB, Awad SI, Soliman RH, Hassan WA. The endosymbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis in Egyptian Women and its correlation with pathogenicity. Parasitol United J [serial online] 2016 [cited 2023 Dec 3];9:80-6. Available from: http://www.new.puj.eg.net/text.asp?2016/9/2/80/205169 |
| Introduction | |  |
Trichomonas vaginalis is a worldwide flagellated protozoan that is considered as one of the most common causes of sexually transmitted disease [1]. Clinically, there is a great variation in disease presentation ranging from no symptoms to severe vaginitis in women or urethritis and prostatitis in men. Symptomatic women with vaginal trichomoniasis usually complain of vaginal discharge, vulvovaginal soreness, pruritus vulvae, dysuria, and dyspareunia [2]. In pregnant women, trichomoniasis may lead to preterm delivery, low birth weight, and increased infant mortality [3],[4]. Moreover, trichomoniasis predisposes individuals to HIV/AIDS and cervical and prostatic cancers [5],[6]. In immunocompromised patients, T. vaginalis can induce pneumonia, bronchitis, and oral lesions [7],[8],[9].
For infection to be established in humans, cytoadherence occurs to vaginal and cervical epithelial cells, and then binds and degrades the vaginal mucus [10]. Upon contact with vaginal epithelial cells, T. vaginalis changes its shape from pear shape to an ameboid form with the release of adhesion molecules as chemoattractants, which lead to attraction of more parasites to the infection site. The morphological changes lead to the formation of areas where tight association between parasite and target cell become evident [11].
Mycoplasma hominis is a type of bacteria, a member of the Mollicutes, frequently affecting human genitalia. The bacterium could be isolated from symptomatic and asymptomatic individuals, and, despite its unclear pathogenic mechanisms, it has been associated with pelvic inflammatory diseases, preterm labor, and low birth weight infants [12],[13]. It was shown that M. hominis could naturally infect T. vaginalis isolates and human epithelial cells [14],[15]. Several studies reported that M. hominis is a natural endosymbiotic bacteria of clinical T. vaginalis isolates regardless of geographic origin; it has been recorded in 75% [16] and 50% [17] of clinical T. vaginalis isolates. Vancini et al. [18] recorded an increase in the cytopathic effect of cultured human epithelial cells and Madin–Darby canine kidney cells infected by T. vaginalis harboring M. hominis.
Dessì et al. [19] described the cellular location of M. hominis in T. vaginalis using confocal microscopy, gentamicin protection assays, and double immunofluorescence. They showed that M. hominis can invade T. vaginalis and persist in its cytoplasm in the apical, basal, and equatorial sections. In contrast, Vancini and Benchimol [20] showed that M. hominis can enter T. vaginalis by endocytosis and anchor themselves by a polar tip to the trichomonad plasma membrane. Evidence of M. hominis replication within T. vaginalis cells was noted, and it was observed that the flagellate might provide the bacteria with resistance during human infection to environmental stresses such as host immunity and pharmacological therapies [19].
However, the exact nature of this intimate relationship is still unknown, but it has been proposed to be a mutually beneficial endosymbiotic relationship [21]. The influence of this association on pathogenicity has so far received little attention. It has been suggested that the symbiosis of M. hominis in T. vaginalis may be linked to metronidazole resistance in vitro [17],[22]. In an in vitro study, Vancini et al. [18] described the cytopathic effect on infected epithelial cells as increased intercellular spaces, decreased viability, and elevated destruction rate. There was also a higher ameboid transformation rate of the trichomonads and extreme phagocytic activity, indicating higher virulence behavior. Thus, the aim of our present study was to detect the association of M. hominis among T. vaignalis Egyptian isolates and to evaluate the pathogenic effects of M. hominis-infected T. vaginalis and M. hominis-free T. vaginalis infection on experimentally infected mice.
| Patients and methods | | |
Type of study
An animal experimental study was performed between July 2015 and January 2016 at the Medical Parasitology Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt.
Patient information and collection of clinical data
A thorough medical history was obtained from 260 women attending Obstetrics and Gynecology outpatient clinics of Suez Canal University and Ismailia General Hospitals, Ismailia, Egypt. Isolates obtained from patients complaining of one or more symptoms such as vaginal discharge, vulval pruritus, dysuria, and/or dyspareunia were considered as symptomatic, whereas isolates obtained from women attending the outpatient clinic for routine checkup, infertility, or family planning and having no suggestive symptoms were considered as asymptomatic. Each patient was subjected to complete history taking, pervaginal examination, and nonlubricated sterile speculum examination. All women who were in the childbearing period (18–45 years) denied a history of douching for at least previous 2–3 days, or use of antibiotics, antiprotozoal, or steroid treatments for the past 15 days.
T. vaginalis isolate collection
Two sterile vaginal cotton swabs were obtained from each participant in the study. The first swab was for wet smear examination, which was immediately examined using a clean glass slide with cover for motile T. vaginalis under ×10 and ×40 objectives. The second swab was immediately inoculated in Diamond’s TYM medium, pH 6.2, supplemented with 10% heat-inactivated horse serum, 100 U/ml penicillin, and 100 µg/mg streptomycin and subcultured every 2–3 days until an axenic culture was obtained [23]. The culture was examined daily for the presence of T. vaginalis trophozoites. If the parasite was not seen, the culture was incubated again for up to 1 week, with daily examination. If no trichomonads were seen, it was considered negative. In the exponential growth phase (4×106) parasites were placed in −70°C freezer for subsequent DNA extraction.
PCR amplification of M. hominis 16S rRNA
According to Mayta et al. [24], axenic cultures containing 4×106 trophozoites were gradually thawed on ice and then pelleted by means of centrifugation at 300 g for 5 min at 4°C. The cellular pellet was washed twice with PBS pH 7.2 at 4°C, and then DNA was extracted using a commercial extraction kit (Gentra Systems, Minneapolis, Minnesota, USA) following the manufacturer’s protocol. PCR primers for the specific amplification of a 334 bp DNA fragment of the 16S rRNA gene of M. hominis were used on T. vaginalis isolates as previously described by Blanchard et al. [25]. The sequences of the oligonucleotides were 5′-CAATGGCTAATGCCGGATACGC-3′ (RNAH1, forward) and 5′-GGTACCGTCA GTCTGCAAT-3′ (RNAH2, reverse). PCR reagents were used to make a 50 µl PCR reaction with 2 µl template DNA. The PCR cycle conditions for the M. hominis gene amplification were 40 cycles each at 95°C for 25 s, 62°C for 1 min, and 72°C for 1 min. Parallel reactions performed with distilled water without DNA were included as negative controls. Amplicons were analyzed on a 1% agarose gel in Tris–borate–EDTA buffer containing ethidium bromide and photographed under ultraviolet visualization.
Identification of M. hominis 16S rRNA by sequencing
The PCR products for the suspected M. hominis samples were purified and sequenced in an automated DNA sequencer ABI3730XL (Solgent Co. Ltd., Daejeon, South Korea).
Experimental mice infection
A total of 184 female albino balb/c mice, 4–6 weeks old, weighing 20–24 g, purchased from Veterinary Medicine Animal Lab, Suez Canal University, were used for in vivo study. Each isolate was inoculated intravaginally into four mice, and an additional control group (four mice) was inoculated with parasite-free culture medium. All mice in the test and control groups were under estrogen treatment throughout the experiment to favor the establishment of the intravaginal T. vaginalis infection. Estradiol treatment was initiated 2 days before the inoculation with the parasite [26], where each mouse was injected intraperitoneally with 0.1 ml of 500 μg estrogen on day 1 and every 2 days throughout the study. On day 3 (2 days after estradiol treatment), each mouse received 2×106 T. vaginalis trophozoites in a 15 μl volume intravaginally. On fourth, fifth, and sixth day (24, 48, and 72 h after T. vaginalis inoculation), the vagina of each infected mouse was washed repeatedly with 30 μl of room temperature Diamond’s TYM medium without antibiotics. The wash was pipetted into 12 ml TYM medium additionally supplemented with antibiotics and incubated at 37°C for a week after inoculation and checked daily for the presence of T. vaginalis trophozoites [26],[27]. All mice were euthanized on the seventh day after infection for histopathology.
Detection of pathogenicity of T. vaginalis isolates
The upper part of the vagina of each scarified mouse was fixed in 10% phosphate-buffered formalin and routinely processed and embedded in paraffin to form the blocks. Serial sections of 4 µm thickness were cut and stained with haematoxylin and eosin for histopathological examination [28]. According to Teras and Roigas [29], histopathological changes were scored from 0 to 4: no, mild, moderate, and severe.
Statistical analysis
The χ2-test was used to test statistical significance for categorical data. A P value less than 0.05 was defined as statistically significant.
Ethical considerations
Informed consent was obtained from patients to use their vaginal discharge samples in the study. The experimental animal studies were conducted in accordance with the international valid guidelines and they were housed independently in well-ventilated, filter-top cages and provided sterile rodent chow and water ad libitum. The animals were maintained in animal house at the Faculty of Medicine, Suez Canal University, at 25°C and with a relative humidity of 40–60%. The research was approved from the Scientific Research Ethical Committee, Faculty of Medicine, Suez Canal University.
| Results | | |
The isolation rate of T. vaginalis in the study population
Of the 260 female participants recruited in the study, 188 (72.3%) manifested symptoms consistent with vaginal trichomoniasis and 72 (27.7%) were asymptomatic. T. vaginalis infection was found in 98 (37.7%) participants, 67 (68.4%) from the symptomatic group and 31 (31.6%) from the asymptomatic group. Fifty-three of them were excluded from the study due to infection with other concomitant microorganisms and/or fungal or bacterial overgrowth during cultivation. Forty-five isolates were successfully obtained and axenized. The main complaint in the symptomatic group was vaginal discharge (100%), followed by soreness (66%), pruritus vulvae (60%), dysuria (50%), and dyspareunia (46%). The minimum and maximum age among participants with trichomoniasis was 20 and 42 years, and the mean age was 31.4±5.75 years. The highest infection rate occurred among women above 25 years of age (83.2%).
Identification of M. hominis associated with T. vaginalis
M. hominis was detected in nine of the 45 (20%) T. vaginalis isolates, with no significant association between M. hominis-infected T. vaginalis isolates among symptomatic and asymptomatic patients ([Table 1]). Association of M. hominis-infected T. vaginalis isolated from symptomatic patients showed significant occurrence among patients suffering from dysuria, vaginal edema, and vaginal erythema ([Table 2]). M. hominis infection was detected in 20% (6/30) of symptomatic female patients and 20% (3/15) of the asymptomatic group. M. hominis infection was identified by the presence of a 334 bp band ([Figure 1]). | Table 1 Detection of Mycoplasma hominis among Trichomonas vaginalis Egyptian isolates
Click here to view |
 | Table 2 Association of Mycoplasma hominis-infected Trichomonas vaginalis with recorded symptoms and signs
Click here to view |
 | Figure 1 PCR-amplified products using M. hominis specific primers RNAH1 and RNAH2. M: 100 bp DNA markers. Lanes: 1,3,5 and 6 show bands at 334 bp indicating positive results.
Click here to view |
Nucleotide sequence accession number
The 16S rRNA sequence of M. hominis was inserted in the GenBank NCBI/EMBL/DDBJ nucleotide sequence data libraries under the following accession no.: KU891983. All nine positive isolates for 16S rRNA M. hominis in the PCR reactions were also correctly identified as M. hominis by 16S rRNA gene sequencing when searched through NCBI blast, revealing 100% homology. The sequence of one M. hominis-positive T. vaginalis isolate is shown in [Figure 2].
Experimental mice infection
The axenically cultured vaginal wash obtained from all mice inoculated intravaginally with T. vaginalis trophozoites showed positive cultures 24 h after inoculation and remained positive for up to 48 and 72 h.
Histopathology results
No statistically significant difference was recorded between pathological changes in vaginal tissue of mice experimentally infected by M. hominis-infected T. vaginalis isolates and noninfected ones. The histopathological scoring proved that 33.3% of M. hominis-infected isolates and 41.7% of noninfected isolates had severe inflammatory changes. However, 66.6 and 58.3% showed mild to moderate changes in the two groups, respectively ([Table 3]). The inflammatory changes revealed diffuse infiltrates of chronic inflammatory cells (lymphocytes, plasma cells, and macrophages, with scattered neutrophils) and congested blood vessels. In severe vaginal inflammation, nodular collections of chronic inflammaotry cells were also seen in the lamina propria ([Figure 3]a–[Figure 3]c). | Table 3 Comparison between the histopathological changes induced by Mycoplasma hominis-infected Trichomonas vaginalis isolates and Mycoplasma hominis-free isolates
Click here to view |
 | Figure 3 Histopathological results: (a) Section in the vagina showing mild inflammatory changes in the form of congested blood vessels (black arrows) and inflammatory cell infiltrate in vaginal wall (red arrows) (H&E, 10×). (b) Section in the vagina showing nodular collection of chronic inflammatory cells (black arrow) (H&E, 10×). (c) Section in the vagina showing inflammatory cell infiltrate is formed mainly of lymphocytes, plasma cells and macrophages, with scattered neutrophils (black arrows). Thick walled blood vessels (red arrows) are also seen (H&E, 20×).
Click here to view |
| Discussion | | |
T. vaginalis is one of the most common protozoan parasites that can induce a considerable morbidity in infected patients. The spectrum of clinical trichomoniasis in women ranges from the asymptomatic carrier state to flagrant vaginitis [2]. Research studies have shown that the difference in surface carbohydrates and proteins lead to the emergence of different strains of T. vaginalis [30],[31],[32]. However, it is not clear whether the variable clinical outcome is influenced more by host factors or by phenotypic expression differences of individual T. vaginalis isolates [33].
It was shown that M. hominis has the ability to assault, survive, and replicate within T. vaginalis cytoplasm where it can get its food, shelter, and long-term survival [13],[19]. It was also noted that transmission of Mycoplasma spp. between individuals may be enhanced by its capability to live inside T. vaginalis isolates [17]. Our study is the first report in Egypt that detected M. hominis-infecting T. vaginalis isolates, and we used sequencing methodology to confirm this analysis. We found that 20% of T. vaginalis isolates were infected with M. homins, which is in agreement with two previous studies that detected similar lower prevalence of infected isolates (20 and 25%, respectively) [34],[35]. Reports on the prevalence of M. hominis-infecting T. vaginalis vary widely according to the geographical location. In China, 50% of the parasite isolates were infected by these bacteria [17], and in South Brazil it was 56.7% [36]. Furthermore, a study performed on 40 T. vaginalis isolates collected from Italy, Angola, and Mozambique showed that 37 (92.5%) isolates were infected with M. hominis. Moreover, the latter authors reported that T. vaginalis isolates [15] exhibit different susceptibilities to M. hominis as shown by variability in the number of M. hominis per cell.
Our PCR results indicated no significant association between M. hominis-infected T. vaginalis isolates among symptomatic and asymptomatic patients despite the significant occurrence among patients suffering from dysuria, vaginal edema, and erythema. The prevalence rate of M. hominis-infected T. vaginalis among symptomatic isolates was the same as in asymptomatic ones. In accordance, a previous study also did not record any enhanced pathological lesions or increase in symptomatic presentations. It was concluded that there is no obligatory association between the two microbes, suggesting that their presence together in the female genital tract, is not essential for the pathogenicity of either of the two pathogens [16]. Moreover, this result was also reached for men suffering from urethritis-like syndromes [37].
Several authors have focused on the initial events required to establish infection by T. vaginalis. Multiple mechanisms are incriminated, such as cellular adhesion, hemolysis, extracellular proteinases and cell detaching factor excretion, and the host inflammatory response [30],[38],[39],[40],[41],[42]. Adhesion of T. vaginalis to vaginal epithelium and release of cytotoxins that cause host cell lysis are extensively studied. However, the role of T. vaginalis in induction of inflammation as a part of its pathogenesis remains elusive. Fichorova et al. [43] described proinflammatory and anti-inflammatory responses to T. vaginalis through the activation of nuclear factor- kappa B (NF- κB) which induces production of proinflammatory cytokines such as interleukin (IL)-1β, IL-12, and TNF-α that are involved in innate and adaptive immunity. Other authors showed that T. vaginalis may inhibit the NF- κB activity of macrophages and induce neutrophil apoptosis through the activation of caspase 3 and reduced expression of the neutrophil antiapoptotic protein [44],[45]. Fiori et al. [46] hypothesized that one possible explanation for this variability could be related to the symbiotic relationship with M. hominis.
Trichomoniasis is one example of diseases in which host–parasite interaction affects the outcome of the infection [6]. To evaluate the pathogenicity of the parasite, a suitable model is needed. Mice have been considered as the most common animal used in experimental trichomoniasis. To prompt and establish infection successfully, pre-estrogenization must be carried out. This could induce estrus cycle, increase glycogen levels, and cause a slight drop in vaginal pH, which potentiate infection by T. vaginalis [47]. Several studies reported that there was an increase in parasite load, an elevated number of vaginal epithelial cells in vaginal discharge, and an increased ability to cause exfoliation of these cells in mice inoculated with symptomatic T. vaginalis isolates as compared with asymptomatic ones [48],[49],[50]. However, Honigberg [51] reported that symptomatic T. vaginalis isolates were able to stimulate strong chemotactic responses toward polymorphonuclear leukocytes, leading to higher inflammatory response manifested as leukorrhea as compared with those isolated from asymptomatic cases.
In the present work, there was no significant difference between pathological changes in vaginal tissue of mice experimentally infected by T. vaginalis isolates harboring M. hominis and T. vaginalis isolates not infected with M. hominis. In 2013, an in vitro study carried out by Fiori et al. [46] showed that symbiotically associated T. vaginalis and M. hominis elicited a synergistic effect over the proinflammatory response of human macrophages. T. vaginalis and M. hominis proved to be more potent inducers of inflammatory mediators such as IL-8, TNF-α, IL-1β, and IL-23. The researchers suggested that this happens in vivo as well, thus affecting the severity of the disease, and that this synergistic upregulation of inflammatory cytokines may have impact on several risks associated with trichomoniasis (HIV and cancer) believed to be linked to chronic inflammatory phenomena. Our results contrast these findings as we showed that there is no statistically significant difference between infected T. vaginalis isolates and noninfected ones when studied experimentally in vivo.
Conclusion
This is the first report studying the association between T. vaginalis infection and M. hominis among Egyptian T. vaginalis isolates, wherein no association was detected as regards the symptomatic status. Our study was limited by the small sample size because of the significant loss of isolates secondary to poor growth kinetics. Further research is needed on a larger sample size to investigate infection by T. vaginalis when symbiotically associated with M. hominis and to further elucidate the impact of M. hominis-infected isolates on patient clinical presentation.
Authors’ contribution: S. Awad suggested the research idea, shared in manuscript writing; E. El-Gayar planned the study design, shared in the experimental studies and manuscript writing; A.B. Mokhtar shared in the experimental studies and manuscript writing; R.H. Soliman shared in manuscript writing; W.A. Hassan assessed the histopathological results.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
| References | | |
| 1. | Hobbs MM, Seña AC, Swygard H, Schwebke J. Trichomonas vaginalis and trichomoniasis. Sex Transm Dis 2008; 771–793  |
| 2. | Sherrard J, Donders G, White D, Jensen J. European (IUSTI/WHO) guideline on the management of vaginal discharge. Int J STD AIDS 2011; 22:1–23. |
| 3. | Cotch MF, Pastorek JG 2nd, Nugent RP, Hillier SL, Gibbs RS, Martin DH et al. Trichomonas vaginalis associated with low birth weight and preterm delivery. The Vaginal Infections and Prematurity Study Group. Sex Transm Dis 1997; 24:353–360. |
| 4. | Pararas MV, Skevaki CL, Kafetzis DA. Preterm birth due to maternal infection: Causative pathogens and modes of prevention. Eur J Clin Microbiol Infect Dis 2006; 25:562–569. |
| 5. | Sutcliffe S. Sexually transmitted infections and risk of prostate cancer: review of historical and emerging hypotheses. Future Oncol 2010; 6:1289–1311. |
| 6. | Twu O, Dessí D, Vu A, Mercer F, Stevens GC, de Miguel N et al. Trichomonas vaginalis homolog of macrophage migration inhibitory factor induces prostate cell growth, invasiveness, and inflammatory responses. Proc Natl Acad Sci USA 2014; 111:8179–8184. |
| 7. | Johnston VJ, Mabey DC. Global epidemiology and control of Trichomonas vaginalis. Curr Opin Infect Dis 2008; 21:56–64. |
| 8. | McClelland RS. Trichomonas vaginalis infection: can we afford to do nothing? J Infect Dis 2008; 197:487–489. |
| 9. | Van der Pol B. Trichomonas vaginalis infection: the most prevalent nonviral sexually transmitted infection receives the least public health attention. Clin Infect Dis 2007; 44:23–25. |
| 10. | Addis MF, Rappelli P, Fiori PL. Host and tissue specificity of Trichomonas vaginalis is not mediated by its known adhesion proteins. Infect Immun 2000; 68:4358–4360. |
| 11. | Arroyo R, González‐Robles A, Martínez‐Palomo A, Alderete J. Signalling of Trichomonas vaginalis for amoeboid transformation and adhesin synthesis follows cytoadherence. Mol Microbiol 1993; 7:299–309. |
| 12. | Taylor-Robinson D, Munday P. Mycoplasmal infection of the female genital tract and its complications. Genital tract infection in women. Edinburgh, UK: Churchill Livingstone Ltd; 1988. 228–247 |
| 13. | Dessì D, Rappelli P, Diaz N, Cappuccinelli P, Fiori PL. Mycoplasma hominis and Trichomonas vaginalis: a unique case of symbiotic relationship between two obligate human parasites. Front Biosci 2006; 11:2028–2034. |
| 14. | Rappelli P, Addis MF, Carta F, Fiori PL. Mycoplasma hominis parasitism of Trichomonas vaginalis. Lancet 1998; 352:1286. |
| 15. | Rappelli P, Carta F, Delogu G, Addis MF, Dessì D, Cappuccinelli P, Fiori PL. Mycoplasma hominis and Trichomonas vaginalis symbiosis: multiplicity of infection and transmissibility of M. hominis to human cells. Arch Microbiol 2001; 175:70–74. |
| 16. | Van Belkum A, van der Schee C, van der Meijden WI, Verbrugh HA, Sluiters HJ. A clinical study on the association of Trichomonas vaginalis and Mycoplasma hominis infections in women attending a sexually transmitted disease (STD) outpatient clinic. FEMS Immunol Med Microbiol 2001; 32:27–32. |
| 17. | Xiao JC, Xie LF, Fang SL, Gao MY, Zhu Y, Song LY et al. Symbiosis of Mycoplasma hominis in Trichomonas vaginalis may link metronidazole resistance in vitro. Parasitol Res 2006; 100:123–130. |
| 18. | Vancini RG, Pereira-Neves A, Borojevic R, Benchimol M. Trichomonas vaginalis harboring Mycoplasma hominis increases cytopathogenicity in vitro. Eur J Clin Microbiol Infect Dis 2008; 27:259–267. |
| 19. | Dessì D, Delogu G, Emonte E, Catania MR, Fiori PL, Rappelli P. Long-term survival and intracellular replication of Mycoplasma hominis in Trichomonas vaginalis cells: potential role of the protozoon in transmitting bacterial infection. Infect Immun 2005; 73:1180–1186. |
| 20. | Vancini RG, Benchimol M. Entry and intracellular location of Mycoplasma hominis in Trichomonas vaginalis. Arch Microbiol 2008; 189:7–18. |
| 21. | Morada M, Manzur M, Lam B, Tan C, Tachezy J, Rappelli P et al. Arginine metabolism in Trichomonas vaginalis infected with Mycoplasma hominis. Microbiology 2010; 156(Pt 12):3734–3743. |
| 22. | Wang PJ, Xie CB. Mycoplasma hominis symbiosis and Trichomonas vaginalis metronidazole resistance. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi 2012; 30:210–213. |
| 23. | Diamond LS, Clark CG, Cunnick CC. YI-S, a casein-free medium for axenic cultivation of Entamoeba histolytica, related Entamoeba, Giardia intestinalis and Trichomonas vaginalis. J Eukaryot Microbiol 1995; 42:277–278. |
| 24. | Mayta H, Gilman RH, Calderon MM, Gottlieb A, Soto G, Tuero I et al. 18S ribosomal DNA-based PCR for diagnosis of Trichomonas vaginalis. J Clin Microbiol 2000; 38:2683–2687. |
| 25. | Blanchard A, Yáñez A, Dybvig K, Watson HL, Griffiths G, Cassell GH. Evaluation of intraspecies genetic variation within the 16S rRNA gene of Mycoplasma hominis and detection by polymerase chain reaction. J Clin Microbiol 1993; 31:1358–1361. |
| 26. | Coombs G, Bremner A, Markham D, Latter V, Walters M, North M. Intravaginal growth of Trichomonas vaginalis in mice. Acta Universitatis Carolinae-Biologica 1986; 30:387–392. |
| 27. | Lushbaugh WB, Blossom AC, Shah PH, Banga AK, Jaynes JM, Cleary JD, Finley RW. Use of intravaginal microbicides to prevent acquisition of Trichomonas vaginalis infection in Lactobacillus-pretreated, estrogenized young mice. Am J Trop Med Hyg 2000; 63:284–289. |
| 28. | Chen WL, Chen JF, Zhong XR, Liang P, Lin W. Ultrastructural and immunohistochemical studies on Trichomonas vaginalis adhering to and phagocytizing genitourinary epithelial cells. Chin Med J (Engl) 2004; 117:376–381. |
| 29. | Teras J, Roigas E. Characteristics of the patho-morphological reaction in cases of experimental infection with Trichomonas vaginalis. Wiad Parazytol 1966; 12:161–172. |
| 30. | Hirt RP, Noel CJ, Sicheritz-Ponten T, Tachezy J, Fiori PL. Trichomonas vaginalis surface proteins: a view from the genome. Trends Parasitol 2007; 23:540–547. |
| 31. | Singh BN, Hayes GR, Lucas JJ, Sommer U, Viseux N, Mirgorodskaya E et al. Structural details and composition of Trichomonas vaginalis lipophosphoglycan in relevance to the epithelial immune function. Glycoconj J 2009; 26:3–17. |
| 32. | De Miguel N, Lustig G, Twu O, Chattopadhyay A, Wohlschlegel JA, Johnson PJ. Proteome analysis of the surface of Trichomonas vaginalis reveals novel proteins and strain-dependent differential expression. Mol Cell Proteomics 2010; 9:1554–1566. |
| 33. | Meade JC, de Mestral J, Stiles JK, Secor WE, Finley RW, Cleary JD, Lushbaugh WB. Genetic diversity of Trichomonas vaginalis clinical isolates determined by EcoRI restriction fragment length polymorphism of heat-shock protein 70 genes. Am J Trop Med Hyg 2009; 80:245–251. |
| 34. | Butler SE, Augostini P, Secor WE. Mycoplasma hominis infection of Trichomonas vaginalis is not associated with metronidazole-resistant trichomoniasis in clinical isolates from the United States. Parasitol Res 2010; 107:1023–1027. |
| 35. | Hampl V, Vanácová S, Kulda J, Flegr J. Concordance between genetic relatedness and phenotypic similarities of Trichomonas vaginalis strains. BMC Evol Biol 2001; 1:11. |
| 36. | da Luz Becker D, dos Santos O, Frasson AP, de Vargas Rigo G, Macedo AJ, Tasca T. High rates of double-stranded RNA viruses and Mycoplasma hominis in Trichomonas vaginalis clinical isolates in South Brazil. Infect Genet Evol 2015; 34:181–187. |
| 37. | Gall H, Beckert H, Meier-Ewert H, Tümmers U, Pust R, Peter R. Pathogen spectrum of urethritis in the man. Hautarzt 1999; 50:186–193. |
| 38. | Kucknoor AS, Mundodi V, Alderete J. Adherence to human vaginal epithelial cells signals for increased expression of Trichomonas vaginalis genes. Infect Immun 2005; 73:6472–6478. |
| 39. | Alderete J, Provenzano D. The vagina has reducing environment sufficient for activation of Trichomonas vaginalis cysteine proteinases. Genitourin Med 1997; 73:291–296. |
| 40. | Garber GE, Lemchuk-Favel LT, Bowie WR. Isolation of a cell-detaching factor of Trichomonas vaginalis. J Clin Microbiol 1989; 27:1548–1553. |
| 41. | Ryan CM, de Miguel N, Johnson PJ. Trichomonas vaginalis: current understanding of host-parasite interactions. Essays Biochem 2011; 51:161–175. |
| 42. | Figueroa-Angulo EE, Rendón-Gandarilla FJ, Puente-Rivera J, Calla-Choque JS, Cárdenas-Guerra RE, Ortega-López J et al. The effects of environmental factors on the virulence of Trichomonas vaginalis. Microbes Infect 2012; 14:1411–1427. |
| 43. | Fichorova RN, Lee Y, Yamamoto HS, Takagi Y, Hayes GR, Goodman RP et al. Endobiont viruses sensed by the human host–beyond conventional antiparasitic therapy. PLoS One 2012; 7:e48418. |
| 44. | Chang J-H, Ryang Y-S, Morio T, Lee S-K, Chang E-J. Trichomonas vaginalis inhibits proinflammatory cytokine production in macrophages by suppressing NF-kappaB activation. Mol Cells 2004; 18:177–185. |
| 45. | Kang J, Song H, Ryu J, Shin M, Kim J, Cho Y et al. Trichomonas vaginalis promotes apoptosis of human neutrophils by activating caspase-3 and reducing Mcl-1 expression. Parasite Immunol 2006; 28:439–446. |
| 46. | Fiori PL, Diaz N, Cocco AR, Rappelli P, Dessì D. Association of Trichomonas vaginalis with its symbiont Mycoplasma hominis synergistically upregulates the in vitro proinflammatory response of human monocytes. Sex Transm Infect 2013; 89:449–454. |
| 47. | Wira CR, Sandoe CP. Specific IgA and IgG antibodies in the secretions of the female reproductive tract: effects of immunization and estradiol on expression of this response in vivo. J Immunol 1987; 138:4159–4164. |
| 48. | Malla N, Paintlia M, Gupta I, Ganguly N, Mahajan R. Experimental intravaginal trichomoniasis induced with strains of Trichomonas vaginalis isolated from symptomatic and asymptomatic women. J Parasit Dis 1999; 23:89–96. |
| 49. | Demirezen S, Safi Z, Beksaç S. The interaction of Trichomonas vaginalis with epithelial cells, polymorphonuclear leucocytes and erythrocytes on vaginal smears: light microscopic observation. Cytopathol 2000; 11:326–332. |
| 50. | Valadkhani Z, Sharma S, Harjai K, Gupta I, Malla N. Evaluation of Trichomonas vaginalis isolates from symptomatic and asymptomatic patients in mouse model. Iran J Publ Health 2004; 33:60–66. |
| 51. | Honigberg B. Trichomonads parasitic in humans. Int J Gynecol Pathol 1991; 10:405. |
[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3]
|
Search Pubmed for