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Flow cytometry evaluation of in vitro susceptibility of bovine isolates of Tritrichomonas foetus to metronidazole. Vet Parasitol 2019; 267:84-89. [PMID: 30878091 DOI: 10.1016/j.vetpar.2019.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/02/2019] [Accepted: 02/09/2019] [Indexed: 11/23/2022]
Abstract
Bovine Trichomonosis, an endemic sexually transmitted disease in countries with extensive livestock and natural service, represents one of the most common causes of reproductive failure. 5-nitroimidazoles and their derivatives are used for its treatment, mainly metronidazole (Mz). The emergence of resistance mechanisms adopted by the parasites against the drug and failure of the treatments suggest the need to investigate susceptibility and obtain current values. The available information of in vitro susceptibility of these drugs comes from the use of a diversity of methodologies and criteria, especially observation of the mobility of the parasite under the optical microscope to evaluate its viability. These techniques are arduous and time consuming and lead to a subjective assessment dependent on the operator, the methodology used, and the morphology adopted by the protozoan. In this sense, flow cytometry has proven to be a fast and efficient method to evaluate viability in other protozoa. The aim of this study was to evaluate the in vitro susceptibility of six bovine isolates of Tritrichomonas foetus to Mz in aerobic (AC) and anaerobic (ANC) conditions by means of the calculation of the 50% inhibitory concentration (IC50), by flow cytometry, and also to analyze minimum lethal concentration (MLC) by means of recovery tests post-treatment in vitro. IC50 values ranged from 1.06 to 1.25 μM in ANC and from 1.44 to 3.03 μM in AC, these being the only ones reported at 48 h for these protozoa. With respect to MLC at 48 h, the results were from 3.67 to 7.35 μM in ANC, and from 7.35 to 14.7 μM for AC, where two isolates (Tf0 and Tf2) for AC and one (Tf2) for ANC showed higher values than those described in the literature. Flow cytometry has proven to be an effective, rapid and objective methodology and very useful in susceptibility tests. The data obtained through these tests allow us to describe the susceptibility exhibited by these protozoa, this being valuable information when establishing dosages in Mz treatments.
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2
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Ghotaslou R, Bannazadeh Baghi H, Alizadeh N, Yekani M, Arbabi S, Memar MY. Mechanisms of Bacteroides fragilis resistance to metronidazole. INFECTION GENETICS AND EVOLUTION 2018; 64:156-163. [PMID: 29936037 DOI: 10.1016/j.meegid.2018.06.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/09/2018] [Accepted: 06/16/2018] [Indexed: 01/01/2023]
Abstract
Metronidazole-resistant Bacteroides fragilis (B. fragilis) have been reported worldwide. Several mechanisms contribute to B. fragilis resistance to metronidazole. In some cases, the mechanisms of metronidazole resistance are unknown. Understanding the mechanisms of resistance is important for therapy, the design of new alternative drugs, and control of resistant strains. In this study, a comprehensive review of the B. fragilis resistance mechanisms to metronidazole was prepared. The rate of metronidazole-resistant B. fragilis has been reported as ranging from 0.5% to 7.8% in many surveys. According to CLSI, isolates with MICs ≥32 μg/mL are considered to be metronidazole-resistant. In the majority of cases, metronidazole resistance in B. fragilis is coupled with the existence of nim genes. Metronidazole resistance could be induced in nim-negative strains by exposure to sub-MIC levels of metronidazole. There are multi-drug efflux pumps in B. fragilis which can pump out a variety of substrates such as metronidazole. The recA overexpression and deficiency of feoAB are other reported metronidazole resistance mechanisms in this bacterium.
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Affiliation(s)
- Reza Ghotaslou
- The Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Bannazadeh Baghi
- Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Naser Alizadeh
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mina Yekani
- Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Shahram Arbabi
- The Liver and Gastrointestinal Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Department of Microbiology, School of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Yousef Memar
- Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran.
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Vuotto C, Moura I, Barbanti F, Donelli G, Spigaglia P. Subinhibitory concentrations of metronidazole increase biofilm formation in Clostridium difficile strains. Pathog Dis 2015; 74:ftv114. [PMID: 26656887 DOI: 10.1093/femspd/ftv114] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2015] [Indexed: 01/05/2023] Open
Abstract
Resistance mechanism to metronidazole is still poorly understood, even if the number of reports on Clostridium difficile strains with reduced susceptibility to this antibiotic is increasing. In this study, we investigated the ability of the C. difficile strains 7032994, 7032985 and 7032989, showing different susceptibility profiles to metronidazole but all belonging to the PCR ribotype 010, to form biofilm in vitro in presence and absence of subinhibitory concentrations of metronidazole. The quantitative biofilm production assay performed in presence of metronidazole revealed a significant increase in biofilm formation in both the susceptible strain 7032994 and the strain 7032985 exhibiting a reduced susceptibility to this antibiotic, while antibiotic pressure did not affect the biofilm-forming ability of the stable-resistant strain 7032989. Moreover, confocal microscopy analysis showed an abundant biofilm matrix production by the strains 7032994 and 7032885, when grown in presence of metronidazole, but not in the stable-resistant one. These results seem to demonstrate that subinhibitory concentrations of metronidazole are able to enhance the in vitro biofilm production of the above-mentioned PCR ribotype 010 C. difficile strains, susceptible or with reduced susceptibility to this antibiotic, suggesting a possible role of biofilm formation in the multifactorial mechanism of metronidazole resistance developed by C. difficile.
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Affiliation(s)
- Claudia Vuotto
- Microbial Biofilm Laboratory, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy
| | - Ines Moura
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Fabrizio Barbanti
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
| | - Gianfranco Donelli
- Microbial Biofilm Laboratory, IRCCS Fondazione Santa Lucia, 00179 Rome, Italy
| | - Patrizia Spigaglia
- Department of Infectious, Parasitic and Immune-mediated Diseases, Istituto Superiore di Sanità, 00161 Rome, Italy
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4
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Increase number of mitochondrion-like organelle in symptomatic Blastocystis subtype 3 due to metronidazole treatment. Parasitol Res 2015; 115:391-6. [PMID: 26481491 DOI: 10.1007/s00436-015-4760-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 09/28/2015] [Indexed: 01/06/2023]
Abstract
Blastocystis sp., an intestinal organism is known to cause diarrhea with metronidazole regarded as the first line of treatment despite reports of its resistance. The conflicting reports of variation in drug treatment have been ascribed to subtype differences. The present study evaluated in vitro responses due to metronidazole on ST3 isolated from three symptomatic and asymptomatic patients, respectively. Symptomatic isolates were obtained from clinical patients who showed symptoms such as diarrhea and abdominal bloating. Asymptomatic isolates from a stool survey carried out in a rural area. These patients had no other pathogens other than Blastocystis. Ultrastructural studies using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed drug-treated ST3 from symptomatic patients were irregular and amoebic with surface showing high-convoluted folding when treated with metronidazole. These organisms had higher number of mitochondrion-like organelle (MLO) with prominent cristae. However, the drug-treated ST3 from asymptomatic persons remained spherical in shape. Asymptomatic ST3 showed increase in the size of its central body with the MLO located at the periphery.
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5
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Das Roy L, Giri S, Singh S, Giri A. Effects of radiation and vitamin C treatment on metronidazole genotoxicity in mice. Mutat Res 2013; 753:65-71. [PMID: 23416157 DOI: 10.1016/j.mrgentox.2013.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2012] [Revised: 01/26/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
Abstract
The impact of exposure to low dose radiation (LDR) on human health is not clear. Besides, cross adaptation or sensitization with pharmaceutical agents may modify the risk of LDR. In the present study, we analyzed the interaction of radiation and metronidazole (MTZ) in inducing chromosome aberration (CA) and micronucleus (MN) in the bone marrow cells of Balb/C mice in vivo. Further, we evaluated the efficacy of vitamin C to reduce MTZ induced genotoxicity. We found that 10, 20 and 40mg/kg of MTZ induced dose dependent increase in the frequency of CA (r=0.9923, P<0.01) as well as MN (r=0.9823, P<0.05) in polychromatic erythrocytes. However, MTZ did not affect the ratio of polychromatic erythrocytes to normochromatic erythrocytes indicating lack of cytotoxicity. Supplementation with vitamin C prior to MTZ treatment significantly reduced the frequency of CA (P<0.001) as well as MN (P<0.001). Radiation (0.5Gy) exposure prior to MTZ treatment produced a less than additive (for CA) to additive (for MN) effects. However, radiation exposure following MTZ treatment produced additive (for CA) and synergistic (for MN) effects. Further, vitamin C pre-treatment also reduced the genotoxicity indices following the combined treatment of MTZ and radiation. Our findings suggest that MTZ may sensitize bone marrow cells to radiation exposure and enhances genotoxicity. We recommend more studies on the interaction of LDR and marketed pharmaceuticals to minimize possible harmful outcomes through appropriate precautionary measures.
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Affiliation(s)
- Lopamudra Das Roy
- Department of Life Science & Bioinformatics, Assam University, Silchar, India
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6
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Müller M, Mentel M, van Hellemond JJ, Henze K, Woehle C, Gould SB, Yu RY, van der Giezen M, Tielens AGM, Martin WF. Biochemistry and evolution of anaerobic energy metabolism in eukaryotes. Microbiol Mol Biol Rev 2012; 76:444-95. [PMID: 22688819 PMCID: PMC3372258 DOI: 10.1128/mmbr.05024-11] [Citation(s) in RCA: 498] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Major insights into the phylogenetic distribution, biochemistry, and evolutionary significance of organelles involved in ATP synthesis (energy metabolism) in eukaryotes that thrive in anaerobic environments for all or part of their life cycles have accrued in recent years. All known eukaryotic groups possess an organelle of mitochondrial origin, mapping the origin of mitochondria to the eukaryotic common ancestor, and genome sequence data are rapidly accumulating for eukaryotes that possess anaerobic mitochondria, hydrogenosomes, or mitosomes. Here we review the available biochemical data on the enzymes and pathways that eukaryotes use in anaerobic energy metabolism and summarize the metabolic end products that they generate in their anaerobic habitats, focusing on the biochemical roles that their mitochondria play in anaerobic ATP synthesis. We present metabolic maps of compartmentalized energy metabolism for 16 well-studied species. There are currently no enzymes of core anaerobic energy metabolism that are specific to any of the six eukaryotic supergroup lineages; genes present in one supergroup are also found in at least one other supergroup. The gene distribution across lineages thus reflects the presence of anaerobic energy metabolism in the eukaryote common ancestor and differential loss during the specialization of some lineages to oxic niches, just as oxphos capabilities have been differentially lost in specialization to anoxic niches and the parasitic life-style. Some facultative anaerobes have retained both aerobic and anaerobic pathways. Diversified eukaryotic lineages have retained the same enzymes of anaerobic ATP synthesis, in line with geochemical data indicating low environmental oxygen levels while eukaryotes arose and diversified.
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Affiliation(s)
| | - Marek Mentel
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
| | - Jaap J. van Hellemond
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Katrin Henze
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Christian Woehle
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Sven B. Gould
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Re-Young Yu
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
| | - Mark van der Giezen
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Aloysius G. M. Tielens
- Department of Medical Microbiology and Infectious Diseases, Erasmus University Medical Center, Rotterdam, Netherlands
| | - William F. Martin
- Institute of Molecular Evolution, University of Düsseldorf, Düsseldorf, Germany
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7
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Galvão BPGV, Meggersee RL, Abratt VR. Antibiotic resistance and adhesion potential of Bacteroides fragilis clinical isolates from Cape Town, South Africa. Anaerobe 2011; 17:142-6. [PMID: 21530667 DOI: 10.1016/j.anaerobe.2011.02.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 02/01/2011] [Accepted: 02/17/2011] [Indexed: 10/18/2022]
Abstract
The minimum inhibitory concentrations of 23 Bacteroides fragilis clinical isolates from Cape Town, South Africa, were established using the E-test method. Eight percent of the strains were found to be highly resistant to metronidazole (≥256 mg/L) imipenem and cefoxitin. This is an 8% increase in resistance compared to the previous metronidazole susceptibility screening performed in South Africa in 1998. Clindamycin was the most effective antibiotic with all strains showing sensitivity. Most of the strains (65%) were tetracycline resistant, while one strain, B. fragilis GSH15, showed multidrug resistance to metronidazole, imipenem, cefoxitin and tetracycline. PCR screening revealed that none of the strains contained any of the published nim genes. The particle agglutination assay was employed to determine the ability of the isolates to bind the ECM components fibronectin, laminin, mucin and collagen. This revealed that 78% of the clinical isolates adhered to all four ECM components to varying extents, with the strongest being to laminin and weakest to mucin and collagen Type I.
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Affiliation(s)
- B P G V Galvão
- Department of Molecular and Cellular Biology, University of Cape Town, Rondebosch, South Africa
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8
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Genotoxicity revaluation of three commercial nitroheterocyclic drugs: nifurtimox, benznidazole, and metronidazole. J Parasitol Res 2009; 2009:463575. [PMID: 20981287 PMCID: PMC2963127 DOI: 10.1155/2009/463575] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 07/09/2009] [Accepted: 08/03/2009] [Indexed: 12/28/2022] Open
Abstract
Nitroheterocyclic compounds are widely used as therapeutic agents against a variety of protozoan and bacterial infections. However, the literature on these compounds, suspected of being carcinogens, is widely controversial. In this study, cytotoxic and genotoxic potential of three drugs, Nifurtimox (NFX), Benznidazole (BNZ), and Metronidazole (MTZ) was re-evaluated by different assays. Only NFX reduces survival rate in actively proliferating cells. The compounds are more active for base-pair substitution than frameshift induction in Salmonella; NFX and BNZ are more mutagenic than MTZ; they are widely dependent from nitroreduction whereas microsomal fraction S9 weakly affects the mutagenic potential. Comet assay detects BNZ- and NFX-induced DNA damage at doses in the range of therapeutically treated patient plasma concentration; BNZ seems to mainly act through ROS generation whereas a dose-dependent mechanism of DNA damaging is suggested for NFX. The lack of effects on mammalian cells for MTZ is confirmed also in MN assay whereas MN induction is observed for NFX and BNZ. The effects of MTZ, that shows comparatively low reduction potential, seem to be strictly dependent on anaerobic/hypoxic conditions. Both NFX and BNZ may not only lead to cellular damage of the infective agent but also interact with the DNA of mammalian cells.
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9
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Peyghan R, Powell MD, Zadkarami MR. In vitro effect of garlic extract and metronidazole against Neoparamoeba pemaquidensis, page 1987 and isolated amoebae from Atlantic salmon. Pak J Biol Sci 2008; 11:41-7. [PMID: 18819591 DOI: 10.3923/pjbs.2008.41.47] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Neoparamoeba pemaquidensis believed to be the most prevalent parasite of Atlantic salmon industry in Australia. In the present study, the in vitro effects of crude extract of garlic and metronidazole were investigated using a primary culture toxicity assay. Garlic extract appeared to be completely effective at killing a cultured strain (NP251002) of Neoparamoeba pemaquidensis in vitro at a dilution of 1:100 with in 24 h. The number of viable Amoebae after using garlic extract in lower dilutions (1:200, 1:400, 1:800, 1:1000) for 24 h, also were significantly lower than in the control group. Garlic extract was also efficacious at killing wild type Amoebae that isolated from the diseased fish showing clinical signs of AGD. Metronidazole had no clear effect against Neoparamoeba pemaquidensis (NP251002) even in a concentration of 50 mg L(-1) for 24 h. However some morphological changes have occurred in metronidazole-treated Amoebae after 5 days of exposure.
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Affiliation(s)
- R Peyghan
- Faculty of Veterinary, Shahid Chamran University of Ahvaz, Ahvaz, Iran
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10
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Wu Q, Wang M, Chen ZC, Lu DS, Lin XF. Enzymatic synthesis of metronidazole esters and their monosaccharide ester derivatives. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2006.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Mallat H, Podglajen I, Lavarde V, Mainardi JL, Frappier J, Cornet M. Molecular characterization of Trichomonas tenax causing pulmonary infection. J Clin Microbiol 2004; 42:3886-7. [PMID: 15297557 PMCID: PMC497589 DOI: 10.1128/jcm.42.8.3886-3887.2004] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
MESH Headings
- Animals
- DNA Primers
- Humans
- Lung Diseases, Parasitic/diagnosis
- Lung Diseases, Parasitic/diagnostic imaging
- Male
- Middle Aged
- RNA, Protozoan/genetics
- RNA, Protozoan/isolation & purification
- RNA, Ribosomal, 5.8S/genetics
- RNA, Ribosomal, 5.8S/isolation & purification
- Radiography, Thoracic
- Tomography, X-Ray Computed
- Trichomonas/genetics
- Trichomonas/isolation & purification
- Trichomonas Infections/diagnosis
- Trichomonas Infections/diagnostic imaging
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Affiliation(s)
- Hassan Mallat
- Department of Microbiology, European Georges Pompidou Hospital, Paris, France
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12
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Diniz CG, Santos SG, Pestana ACN, Farias LM, Carvalho MAR. Chromosomal Breakage in the B. fragilis Group Induced by Metronidazole Treatment. Anaerobe 2000. [DOI: 10.1006/anae.2000.0332] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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13
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Wassmann C, Bruchhaus I. Superoxide dismutase reduces susceptibility to metronidazole of the pathogenic protozoan Entamoeba histolytica under microaerophilic but not under anaerobic conditions. Arch Biochem Biophys 2000; 376:236-8. [PMID: 10729211 DOI: 10.1006/abbi.2000.1707] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- C Wassmann
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Str. 74, Hamburg, 20359, Germany
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14
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Jongwutiwes S, Silachamroon U, Putaporntip C. Pentatrichomonas hominis in empyema thoracis. Trans R Soc Trop Med Hyg 2000; 94:185-6. [PMID: 10897364 DOI: 10.1016/s0035-9203(00)90270-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- S Jongwutiwes
- Department of Parasitology, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
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15
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Wassmann C, Hellberg A, Tannich E, Bruchhaus I. Metronidazole resistance in the protozoan parasite Entamoeba histolytica is associated with increased expression of iron-containing superoxide dismutase and peroxiredoxin and decreased expression of ferredoxin 1 and flavin reductase. J Biol Chem 1999; 274:26051-6. [PMID: 10473552 DOI: 10.1074/jbc.274.37.26051] [Citation(s) in RCA: 180] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
To obtain insight into the mechanism of metronidazole resistance in the protozoan parasite Entamoeba histolytica, amoeba trophozoites were selected in vitro by stepwise exposures to increasing amounts of metronidazole, starting with sublethal doses of 4 microM. Subsequently, amoebae made resistant were able to continuously multiply in the presence of a 40 microM concentration of the drug. In contrast to mechanisms of metronidazole resistance in other protozoan parasites, resistant amoebae did not substantially down-regulate pyruvate:ferredoxin oxidoreductase or up-regulate P-glycoproteins, but exhibited increased expression of iron-containing superoxide dismutase (Fe-SOD) and peroxiredoxin and decreased expression of flavin reductase and ferredoxin 1. Episomal transfection and overexpression of the various antioxidant enzymes revealed significant reduction in susceptibility to metronidazole only in those cells overexpressing Fe-SOD. Reduction was highest in transfected cells simultaneously overexpressing Fe-SOD and peroxiredoxin. Although induced overexpression of Fe-SOD did not confer metronidazole resistance to the extent found in drug-selected cells, transfected cells quickly adapted to constant exposures of otherwise lethal metronidazole concentrations. Moreover, metronidazole selection of transfected amoebae favored retention of the Fe-SOD-containing plasmid. These results strongly suggest that peroxiredoxin and, in particular, Fe-SOD together with ferredoxin 1 are important components involved in the mechanism of metronidazole resistance in E. histolytica.
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Affiliation(s)
- C Wassmann
- Bernhard Nocht Institute for Tropical Medicine, Bernhard-Nocht-Strasse 74, 20359 Hamburg, Germany
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16
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Land KM. Focus on drug resistance. Trends Microbiol 1999; 7:344-5. [PMID: 10617349 DOI: 10.1016/s0966-842x(99)01573-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K M Land
- Dept of Microbiology and Immunology, UCLA School of Medicine, Los Angeles, CA 90095-1489, USA.
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17
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Samuelson J. Why metronidazole is active against both bacteria and parasites. Antimicrob Agents Chemother 1999; 43:1533-41. [PMID: 10390199 PMCID: PMC89320 DOI: 10.1128/aac.43.7.1533] [Citation(s) in RCA: 152] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- J Samuelson
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
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18
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Abstract
Trichomonas vaginalis and Tritrichomonas foetus are sexually transmitted pathogens of the genito-urinary tract of humans and cattle, respectively. These organisms are amitochondrial anaerobes possessing hydrogenosomes, double membrane-bound organelles involved in catabolic processes extending glycolysis. The oxidative decarboxylation of pyruvate in hydrogenosomes is coupled to ATP synthesis and linked to ferredoxin-mediated electron transport. This pathway is responsible for metabolic activation of 5-nitroimidazole drugs, such as metronidazole, used in chemotherapy of trichomoniasis. Prolonged cultivation of trichomonads under sublethal pressure of metronidazole results in development of drug resistance. In both pathogenic species the resistance develops in a multistep process involving a sequence of stages that differ in drug susceptibility and metabolic activities. Aerobic resistance, similar to that occurring in clinical isolates of T. vaginalis from treatment-refractory patients, appears as the earliest stage. The terminal stage is characterised by stable anaerobic resistance at which the parasites show very high levels of minimal lethal concentration for metronidazole under anaerobic conditions (approximately 1000 microg ml(-1)). The key event in the development of resistance is progressive decrease and eventual loss of the pyruvate:ferredoxin oxidoreductase so that the drug-activating process is averted. In T. vaginalis at least, the development of resistance is also accompanied by decreased expression of ferredoxin. The pyruvate:ferredoxin oxidoreductase deficiency completely precludes metronidazole activation in T. foetus, while T. vaginalis possesses an additional drug-activating system which must be eliminated before the full resistance is acquired. This alternative pathway involves the hydrogenosomal malic enzyme and NAD:ferredoxin oxidoreductase. Metronidazole-resistant trichomonads compensate for the hydrogenosomal deficiency by an increased rate of glycolysis and by changes in their cytosolic pathways. Trichomonas vaginalis enhances lactate fermentation while T. foetus activates pyruvate conversion to ethanol. Drug-resistant T. foetus also increases activity of the cytosolic NADP-dependent malic enzyme, to enhance the pyruvate producing bypass and provide NADPH required by alcohol dehydrogenase. Production of succinate by this species is abolished. Metabolic changes accompanying in-vitro development of metronidazole resistance demonstrate the versatility of trichomonad metabolism and provide an interesting example of how unicellular eukaryotes can adjust their metabolism in response to the pressure of an unfavorable environment.
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Affiliation(s)
- J Kulda
- Department of Parasitology, Faculty of Science, Charles University, Prague, Czech Republic.
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