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PubMed1995

Cell cytotoxicity of sodium nitrite, sodium nitroprusside and Roussin's black salt against Trichomonas vaginalis.

We have investigated the action of sodium nitrite and other nitrosyl complexes, such as sodium nitroprusside and Roussin's black salt, on the growth of metronidazole-sensitive and resistant strains of Trichomonas vaginalis and their hydrogenosomal enzymes. All three chemicals inhibited the growth of T. vaginalis: sodium nitrite at 8 mM, sodium nitroprusside at 1.2 mM and Roussin's black salt at 0.2 mM. Metronidazole-sensitive (KT9) and resistant (CDC85) isolates showed similar cytotoxicity against these molecules. Specific activities of pyruvate:ferredoxin oxidoreductase and hydrogenase and oxygen uptake rates were decreased in the T. vaginalis isolate treated with sodium nitrite and sodium nitroprusside. However, Roussin's black salt increased the specific activity of pyruvate:ferredoxin oxidoreductase or hydrogenase in CDC85 or KT9 cells and increased the oxygen uptake rate in the KT9 isolate.

Animals↗
PubMed1996

Primary structure of a cytosolic malate dehydrogenase of the amitochondriate eukaryote, Trichomonas vaginalis.

The nucleotide sequence of a gene coding for a 37 kDa subunit of a cytosolic malate dehydrogenase of Trichomonas vaginalis was established. The sequence of a gDNA clone and a cDNA clone, which lacked seven amino-terminal codons, were identical, indicating an absence of introns from the gene. Cell fractionation combined with sequencing of peptide fragments of the purified enzyme showed that the gene codes for an expressed cytosolic enzyme. The derived amino acid sequence was closely related to cytosolic malate dehydrogenases from animals and plants and from the eubacteria Thermus aquaticus and Mycobacterium leprae and was more distant from the enzyme of mitochondria and from Escherichia coli and certain other eubacteria. In phylogenetic reconstructions this enzyme shared a most recent common ancestor with other cytosolic enzymes.

Amino Acid Sequence↗
PubMed1997

Molecular cloning of actin genes in Trichomonas vaginalis and phylogeny inferred from actin sequences.

The parasitic protozoan Trichomonas vaginalis is known to contain the ubiquitous and highly conserved protein actin. A genomic library and a cDNA library have been screened to identify and clone the actin gene(s) of T. vaginalis. The nucleotide sequence of one gene and its flanking regions have been determined. The open reading frame encodes a protein of 376 amino acids. The sequence is not interrupted by any introns and the promoter could be represented by a 10 bp motif close to a consensus motif also found upstream of most sequenced T. vaginalis genes. The five different clones isolated from the cDNA library have similar sequences and encode three actin proteins differing only by one or two amino acids. A phylogenetic analysis of 31 actin sequences by distance matrix and parsimony methods, using centractin as outgroup, gives congruent trees with Parabasala branching above Diplomonadida.

Actins↗
PubMed1998

Cloning and expression of an iron-containing superoxide dismutase in the parasitic protist, Trichomonas vaginalis.

A superoxide dismutase (SOD) gene of the parasitic protist Trichomonas vaginalis was cloned, sequenced, expressed in Escherichia coli, and its gene product characterized. It is an iron-containing dimeric protein with a monomeric mass of 22,067 Da. Southern blots analyses suggested the presence of seven iron-containing (FeSOD) gene copies. Hydrophobic cluster analysis revealed some peculiarities in the 2D structure of the FeSOD from T. vaginalis and a strong structural conservation between prokaryotic and eukaryotic FeSODs. Phylogenetic reconstruction of the SOD sequences confirmed the dichotomy between FeSODs and manganese-containing SODs. FeSODs of protists appeared to group together with homologous proteobacterial enzymes suggesting a possible origin of eukaryotic FeSODs through an endosymbiotic event.

Amino Acid Sequence↗
PubMed2002

Trichomonas vaginalis: observation of coexistence of multiple viruses in the same isolate.

Trichomonas vaginalis is a flagellated, parasitic protozoan that inhabits the urogenital tract of humans. Some isolates of T. vaginalis are infected with a double-stranded RNA (dsRNA) virus, which was described in the literature as homogeneous icosahedral viral particles with an isometric symmetry and 33 nm in diameter. This study examined in detail the viral particles in T. vaginalis isolate 347 and describes a heterogeneous population of viral particles. The different dsRNA viruses were only observed after a change in the technique. The sample was prepared by the negative staining carbon-film method directly onto freshly cleft mica. The detected viruses ranged in size from 33 to 200 nm. Among the shapes observed were filamentous, cylindrical, and spherical particles. These results show that T. vaginalis may be a reservoir for several different dsRNA viruses simultaneously.

Animals↗
PubMed1975

The ultrastructure of Trichomonas vaginalis donné before and after transfer from vaginal secretion to Diamonds medium.

Cell of Trichomonas vaginalis (T. vag.) obtained from five patients with severe trichomoniasis were fixed for electron microscopy directly in the vaginal fluid. Samples of the same material from three of the patients was inoculated into Diamonds medium and propagated for 3-6 weeks. During the first 3-4 weeks in vitro the fine structure of all cells was changed. The shape of the nucleus, the size of the Golgi apparatus and adjacent vesicles, the fine structure of the chromatic granules, and the mastigont were all changed when compared to the organelles of the originally isolated cells. In addition the "ectoplasm" had disappeared, the glycogen granules had become sparse, and the number of free cytoplasmic ribosomes had increased. On the other hand, the large food vacuoles and the cell membranes generally were unchanged. Mycoplasms were observed in the original isolate and were also seen after more than 6 weeks of propagation, both as free organisms in the culture medium and within the large food vacuoles of "in vitro" cultured cells.

Cell Nucleus↗
PubMed1976

In vitro effect of metronidazole on the ultrastructure of Trichomonas vaginalis donné.

The effect of metronidazole on the growth and fine structure of exponeentially growing cells of Trichomonas vaginalis was examined. Cell division stopped about one hour after the addition of 1-4 mug/ml of metronidazole, and the cells were apparently arrested in the interphase. One to two hours after the addition of metronidazole, the movement of flagella and of the undulating membrane had decreased, but cell death had not occurred until 7-8 hours later. The fine structure of the cytoplasm was changed 30 to 60 minutes after addition of metronidazole. Proportionally, the number of polyribosomes had decreased whereas the number of single ribosomes in the cytoplasm had increased. The electron-density of the cytoplasmic matrix was higher in cells which were treated with metronidazole than in cells from control cultures. The findings of the present study indicate that the initial effect of metronidazole on T. vag. cells in vitro is an inhibition of cell multiplication as well as an impairment of protein synthesis.

Cell Wall↗
PubMed1976

The fine structure of cells of Trichomonas vaginalis Donné obtained from the exponential phase of growth and from stationary cultures.

In cells of Trichomonas vaginalis in logarithmic phase of growth (log. T. vaginalis) the number of free cytoplasmic ribosomes was higher than that in cells from stationary cultures (stat. T. vaginalis). Polyribosomes closely surrounding the chromatic granules were present in equal amounts in both categories fo cells, which indicates that they have specific functions and are not directly involved in the protein synthesis of the growing cell. The volume of the Golgi region and of the food vacules were approximately twice as large in log. T. vaginalis cells as in stat. T. vaginalis cells. The round and slightly ovoid chromatic granules were smaller in log. T. vaginalis cells than in stat. T. vaginalis cells, whereas elongated granules were more numerous in the former than in the latter cell type. The elongated chromatic granules presented a coarser texture than ordinary round granules. The chromatic granules probably replicate by binary fission a process which seem to follow an internal reorganization of the granules. Polysaccharides were demonstrated on the cell surface and on the membranes of the Golgi and endocytotic vesicles if sectioned cells were stained with phosphotungstic acid after inert dehydration and embedding in a water-missible methacrylate. Ruthenium red and colloidal iron only showed affinity for the filamentous cell coat.

Cell Membrane↗
PubMed1978

In vitro sensitivity of Trichomonas vaginalis and Candida albicans to chemotherapeutic agents.

Strains of fresh clinical isolates of Trichomonas vaginalis and Candida albicans have been tested in vitro for their sensitivity to eight drugs used in the therapy of monilial and trichomonal vaginitis. Three of the chemotherapeutic agents, chlorchinaldol, clotrimazole and broxyquinoline were effective against both organisms. Tinidazole and metronidazole were active against T. vaginalis. The strains of C. albicans were also sensitive to trichomycin, natamycin and nystatin. Tinidazole was the most effective trichomonacide, clotrimazole and chlorchinaldol were most effective against C. albicans, while chlorchinaldol had the best in vitro effect against both organisms. The ranges of the MICs are compared to values previously reported.

Antifungal Agents↗
PubMed2006

Prevalence of Trichomonas vaginalis isolates with resistance to metronidazole and tinidazole.

Clinical isolates of Trichomonas vaginalis were obtained from women consecutively enrolled in a study of partner notification. Testing of susceptibility to metronidazole and tinidazole was performed. Resistance to metronidazole and tinidazole was present in 17/178 (9.6%) and 1/178 (0.56%) strains, respectively. In vitro resistance was poorly correlated with clinical response to treatment.

Animals↗
PubMed1981

Metronidazole metabolism in cultures of Entamoeba histolytica and Trichomonas vaginalis.

Acetamide forms from metronidazole in cultures of either Entamoeba histolytica or Trichomonas vaginalis as it does in cultures of bacteria which are susceptible to this drug. Under aerobic conditions, the formation of acetamide is more rapid in a strain of T. vaginalis which is more susceptible to metronidazole. Thus, it appears that the formation of acetamide may be associated with the microbiocidal action of metronidazole.

Acetamides↗
PubMed1983

Metabolism and metronidazole uptake in Trichomonas vaginalis isolates with different metronidazole susceptibilities.

Three Trichomonas vaginalis isolates with low in vivo susceptibilities to metronidazole (95% curative dose, greater than 3 X 100 mg kg-1 in subcutaneous infections in mice) were compared with strain ATCC 30001 and with four isolates exhibiting high in vivo susceptibilities (95% curative dose, less than 3 X 15 mg kg-1). Activity of pyruvate:ferredoxin oxidoreductase, anaerobic fermentation, and anaerobic intracellular accumulation of [14C]metronidazole label showed no significant isolate-dependent differences which could be correlated with drug susceptibility. The results suggest that processes providing electrons for metronidazole activation are not defective in the resistant strains. Aerobiosis, known to inhibit the antimicrobial action of metronidazole, inhibited accumulation of label more strongly in resistant isolates than in susceptible ones. No differences were detected, however, between resistant and susceptible isolates in respiration, aerobic fermentation, and the specific activity of NADH and NADPH oxidases, the main terminal oxidases of T. vaginalis. These findings suggest that the production of electrons is not diminished under aerobic conditions. The inhibitory effect of aerobic conditions on metronidazole activation, possibly due to competition for the electrons, is markedly enhanced in the resistant isolates compared to the susceptible ones. The mechanism of this effect, however, remains unknown.

Anaerobiosis↗
PubMed1985

In vitro inhibition of Giardia lamblia and Trichomonas vaginalis growth by bithionol, dichlorophene, and hexachlorophene.

Bithionol, dichlorophene, and hexachlorophene, which are used in treating some helminthic infections, killed trophozoites of Giardia lamblia and Trichomonas vaginalis in modified BI-S-33 and Asami media, respectively. Virtually all G. lamblia and T. vaginalis cells were killed within 24 h with a 0.42 mM concentration of these compounds, except that 0.93 mM dichlorophene was required for sterilizing T. vaginalis in the same period. In modified BI-S-33 and Asami media from which bovine and human sera were omitted, respectively, the inhibitory actions of the compounds against in vitro growth of these protozoa were significantly enhanced. Trophozoites of G. lamblia and T. vaginalis could be killed in shorter than 10 min with 0.074 mM dichlorophene and 0.0025 mM hexachlorophene, respectively, in serum-free media. G. lamblia, which was incubated in the complete medium containing dichlorophene, showed a characteristic swelling of the ventral side which led to disruption of the parasite, whereas bithionol caused a thin crack in the cytoplasm of T. vaginalis incubated in Asami medium. The crack appeared to enlarge and result in vacuolization of T. vaginalis. These observations suggest that bithionol, dichlorophene, and hexachlorophene merit further evaluation to ascertain whether they are useful for treatment of giardiasis and trichomoniasis.

Animals↗
PubMed1985

Use of a time-kill technique for susceptibility testing of Trichomonas vaginalis.

The emergence of metronidazole-resistant Trichomonas vaginalis and questions about the safety of metronidazole are significant concerns in treatment of trichomoniasis. At 24 h, a microtiter assay was used to test antimicrobial susceptibility of 16 recent isolates; the MICs of metronidazole ranged from less than 0.06 to 25 micrograms/ml. Observable motility as an endpoint correlated imperfectly with survival as measured in pour plates. Quantitative pour plate cultures of six T. vaginalis isolates after timed exposures to antimicrobial drugs demonstrated exquisite sensitivity to metronidazole with minimal trichomonacidal concentrations of 0.025 to 0.100 micrograms/ml. Killing of some T. vaginalis isolates by clotrimazole and rosoxacin occurred only at concentrations of 100 micrograms/ml. Resistance to both rosoxacin and clotrimazole correlated with increasing resistance to metronidazole (P less than 0.01).

4-Quinolones↗
PubMed1988

In vitro susceptibility of Trichomonas vaginalis to 50 antimicrobial agents.

We determined the susceptibilities of five strains of Trichomonas vaginalis, one of which was metronidazole resistant, to 50 antimicrobial agents. For the metronidazole-susceptible strains, the most active agents were metronidazole, tinidazole, mebendazole, furazolidone, and anisomycin. Against the resistant strain mebendazole, furazolidone, and anisomycin were the most active. Antifungal agents, beta-lactams, macrolides, aminoglycosides, and folic acid antagonists were ineffective against all strains.

Animals↗
PubMed1988

Effects of antimicrobial agents on growth and chemotaxis of Trichomonas vaginalis.

The motility of viable Trichomonas vaginalis organisms is readily demonstrable in a clinical wet mount or cultured specimens. We attempted to determine whether migration is a dynamic process such that the organisms move to avoid exposure to toxic antimicrobial agents. With the use of axenic cultures of T. vaginalis that were radiolabeled and assayed for chemotaxis in plastic multiwelled plates with a membrane filter inserted to trap organisms, the response of clinical isolates to various antimicrobial agents was studied. Chemotaxis was readily demonstrable and dependent upon factors including time of incubation, media used, and viscosity of media. Nitroimidazoles (e.g., metronidazole) which readily inhibited the growth of these organisms also caused significant chemorepulsion after minutes of exposure. The antifungal imidazoles ketoconazole and miconazole inhibited growth nearly as readily and caused chemorepulsion, but to a lesser degree. The spermicide Nonoxynol-9 also inhibited growth and caused significant chemorepulsion. The minimal concentrations of many compounds which inhibited growth were very similar to those which caused significant chemorepulsion. Imidazole and antibiotics (e.g., penicillin) which did not inhibit growth did not induce any chemotactic effects. Chemotaxis of T. vaginalis is an active and dynamic process, and the organisms display chemorepulsion shortly after exposure to toxic antimicrobial agents, well before toxicity can be demonstrated.

Animals↗
PubMed1996

In vitro effect of tinidazole and furazolidone on metronidazole-resistant Trichomonas vaginalis.

Trichomonas vaginalis is a common sexually transmitted protozoan parasite. Although often considered simply a nuisance infection, T. vaginalis has been implicated in premature rupture of placental membranes and increases in the risk of acquiring human immunodeficiency virus. Metronidazole, a 5-nitroimidazole, is currently the drug of choice to treat T. vaginalis infection. Because some patients have severe reactions to metronidazole and others are infected with metronidazole-resistant T. vaginalis, we were prompted to investigate alternative therapies. Tinidazole, another 5-nitroimidazole used in other countries to treat T. vaginalis infections, and furazolidone, a nitrofuran presently used to treat giardiasis and infections with some anaerobic enteric bacteria, were investigated for effectiveness against 9 metronidazole-susceptible and 12 metronidazole-resistant T. vaginalis patient isolates. The in vitro aerobic and anaerobic minimum lethal concentrations (MLC) and the time for drug efficacy were determined. Tinidazole killed the metronidazole-susceptible isolates at a low MLC but was effective against only 4 of the 12 metronidazole-resistant isolates. In contrast, furazolidone was effective at a low MLC for all isolates. When tinidazole was effective, it required > 6 h to kill trichomonads. However, furazolidone killed both metronidazole-susceptible and resistant trichomonads within 2 to 3 h of exposure. These data suggest that furazolidone may be a good candidate for treating metronidazole-resistant trichomoniasis and that further investigation of this drug is warranted.

Animals↗
PubMed2001

Trifluoromethionine, a prodrug designed against methionine gamma-lyase-containing pathogens, has efficacy in vitro and in vivo against Trichomonas vaginalis.

Methionine gamma-lyase, the enzyme which catalyzes the single-step conversion of methionine to alpha-ketobutyrate, ammonia, and methanethiol, is highly active in many anaerobic pathogenic microorganisms but has no counterpart in mammals. This study tested the hypothesis that this pathogen-specific enzyme can be exploited as a drug target by prodrugs that are exclusively activated by it. Trifluoromethionine was confirmed as such a prodrug and shown to be highly toxic in vitro to the anaerobic protozoan parasite Trichomonas vaginalis, to anaerobic bacteria containing methionine gamma-lyase, and to Escherichia coli expressing the trichomonad gene. The compound also has exceptional activity against the parasite growing in vivo, with a single dose preventing lesion formation in five of the six mice challenged. These findings suggest that trifluoromethionine represents a lead compound for a novel class of anti-infective drugs with potential as chemotherapeutic agents against a range of prokaryotic and eukaryotic anaerobic pathogens.

Animals↗