Mycoplasma hominis and Trichomonas vaginalis symbiosis: multiplicity of infection and transmissibility of M. hominis to human cells

Rappelli, Paola; Carta, Francesco; Delogu, Giuseppe; Addis, Maria Filippa; Dessì, Daniele; Cappuccinelli, Pietro Antonio; Fiori, Pier Luigi

doi:10.1007/s002030000240

Cited by 53 publications

(56 citation statements)

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“…Figure 2C indicates the localization of extracellular and intracellular mycoplasmas. It is interesting that not all T. vaginalis organisms appear to be infected by mycoplasmas: we previously demonstrated, in different T. vaginalis isolates, a strainto-strain difference in the multiplicity of infection by M. hominis, and we also noted a remarkable cell-to-cell difference among the strains (28). In fact, specific features of a single trichomonad cell could be responsible for different numbers of infecting bacteria.…”

Section: Resultsmentioning

confidence: 78%

“…Three of them were naturally infected with M. hominis (SS14, SS15, and MPM2), and one (SS22) was M. hominis free. The presence or absence of mycoplasmas in each trichomonad strain was assessed by both cultural and molecular methods, as described elsewhere (28). T. vaginalis isolates were cultured by daily passages at 1:16 dilution in fresh Diamond's TYM medium (11) plus 10% fetal bovine serum.…”

Section: Methodsmentioning

confidence: 99%

“…More than 90% of T. vaginalis clinical isolates from our collection proved to be infected by M. hominis independent of their geographic origin. Our recent work has allowed us to shed light on some aspects of the phenomenon (28).…”

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confidence: 99%

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Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

et al. 2005

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The existence of a symbiotic relationship between Trichomonas vaginalis and Mycoplasma hominis, which is the first reported example of symbiosis between two obligate human pathogens, has been recently reported by our research group. In this work, we examined the cellular location of M. hominis in respect to T. vaginalis. By using gentamicin protection assays, double immunofluorescence, and confocal microscopy, we obtained strong evidence that M. hominis is located within protozoan cells. 5-Bromodeoxyuridine incorporation assays showed that intracellularly located mycoplasmas actively synthesize DNA. Our results demonstrate that M. hominis has the capability of entering trichomonad cells and of replicating inside the protozoon. These findings suggest that symbiosis might provide the bacteria, during human infection, with the capability to resist to environmental stresses, such as host defense mechanisms and pharmacological therapies.Trichomonas vaginalis is a parasitic protozoon responsible for trichomoniasis, one of the most common sexually transmitted diseases in humans, estimated to affect at least 200 million people worldwide (37). Studies carried out with large groups of women suffering from vaginitis showed that T. vaginalis is clinically associated with Mycoplasma hominis (18, 35), a bacterium that, like the protozoon, resides exclusively in the human genital tract. The association is strictly species specific, since is not observed with Ureaplasma urealyticum, another Mollicutes species that is a much more common inhabitant of the human genital tract. The clinical association between the two pathogens has been recently explained by the demonstration of a symbiotic relationship between T. vaginalis and M. hominis (27). More than 90% of T. vaginalis clinical isolates from our collection proved to be infected by M. hominis independent of their geographic origin. Our recent work has allowed us to shed light on some aspects of the phenomenon (28).The presence of endosymbionts in free-living protozoa is frequently described, but it has been never reported in obligate parasitic protozoa. The first example of symbiosis involving a human pathogen was described for Legionella pneumophila, a bacterial pathogen that is responsible for Legionnaire's disease, and Acanthamoeba sp., a free-living opportunistic amoeba (30). The relationship between T. vaginalis and M. hominis is the only one described so far involving two obligate human pathogens. T. vaginalis is responsible for severe vaginitis accompanied by abdominal pain, itching, and foul-smelling discharge (29) and is mainly asymptomatic in men (20). Moreover, trichomoniasis is associated with an enhanced risk of neoplastic transformation in cervical tissues (38) and increased human immunodeficiency virus seroconversion in women (22,31). The mechanisms by which T. vaginalis exerts its pathogenic effects involve adhesion to host cells (1, 2, 19) and the activity of pH-dependent pore-forming proteins (14, 15) and of cytoskeleton-disrupting proteases (16). M. hominis c...

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Section: Resultsmentioning

confidence: 78%

Section: Methodsmentioning

confidence: 99%

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Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

et al. 2005

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“…The absence of symbiont mycoplasmas was assessed by both cultural and molecular methods, as described elsewhere. 47,48 The numbers of all bacteria were evaluated as CFU (colony-forming units) in specific solid media. The T. vaginalis were counted using a haemocytometric chamber.…”

Section: Pathogens and Their Preparationmentioning

confidence: 99%

Qualitatively distinct patterns of cytokines are released by human dendritic cells in response to different pathogens

et al. 2005

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Summary Dendritic cells produce cytokines that regulate the class of the adaptive immune response. Microbial recognition is mediated, at least in part, by pattern recognition receptors such as Toll‐like receptors, which influence dendritic cell maturation. In humans it is not yet clear how intact pathogens modulate the developing immune response. To address the effects of intact pathogens on the maturation and effector functions of human dendritic cells, we investigated their responses to a number of microbial pathogens. We studied a range of micro‐organisms including Gram‐negative bacteria (Escherichia coli and Salmonella enterica sv. typhimurium), Gram‐positive cocci (Staphylococcus aureus) and atypical bacteria (Mycobacterium tuberculosis and Mycoplasma hominis) as well as the human protozoal parasite Trichomonas vaginalis. The micro‐organisms were fixed in formaldehyde to prevent replication whilst preserving surface morphology. All the pathogens induced similar up‐regulation of dendritic cell activation‐associated cell surface markers but there was a profound difference in the patterns of cytokines produced by the stimulated dendritic cells. Some pathogens (E. coli, Salmonella enterica sv. typhimurium and S. aureus) induced interleukin‐12 (IL‐12), IL‐10 and interferon‐α whereas others (M. tuberculosis, Mycoplasma hominis and T. vaginalis) induced only IL‐10. This differential effect was not altered by costimulation of the dendritic cells through CD40. These results support the notion that human dendritic cells are plastic in their response to microbial stimuli and that the nature of the pathogen dictates the response of the dendritic cell.

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“…Although a symbioisis between Mycoplasma hominis and Trichomonas vaginalis is recognized (Rappelli et al 2001), other infections by Mycoplasma of protozoal cultures are considered contaminants. Mycoplasma infections of cultures of Plasmodium were reported previously to be widespread (Turrini et al 1997 ;Rowe et al 1998), and clearly were of concern because of the ability of the bacterium to potentially alter the biological properties of the protozoans.…”

Section: Introductionmentioning

confidence: 99%

Culture of Neospora caninum in the presence of a Mycoplasma Removal Agent results in the selection of a mutant population of tachyzoites

Hudson

Ellis

2005

Parasitology

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S U M M A R YMycoplasmas are common contaminants of eukaryotic cells grown in tissue culture. A commercially available Mycoplasma Removal Agent (MRA) was therefore assessed for its effect on tachyzoites of Neospora caninum, in order to determine its suitability for further use in parasite cell cultures. Analyses of tachyzoite and excreted-secreted proteins and antigens by SDS-PAGE and Western blotting show that MRA treatment results in the rapid selection of a mutant population that differs from the control and parental lines in its protein and antigen content. The treatment of N. caninum cultures with MRA is therefore not recommended for the eradication of Mycoplasma.

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Mycoplasma hominis and Trichomonas vaginalis symbiosis: multiplicity of infection and transmissibility of M. hominis to human cells

Cited by 53 publications

References 25 publications

Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

Long-Term Survival and Intracellular Replication of Mycoplasma hominis in Trichomonas vaginalis Cells: Potential Role of the Protozoon in Transmitting Bacterial Infection

Qualitatively distinct patterns of cytokines are released by human dendritic cells in response to different pathogens

Culture of Neospora caninum in the presence of a Mycoplasma Removal Agent results in the selection of a mutant population of tachyzoites

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