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Masset Z, Gunaratnam S, Millette M, McFarland LV, Lacroix M. Environmental and Nutritional Parameters Modulating Genetic Expression for Virulence Factors of Clostridioides difficile. Antibiotics (Basel) 2024; 13:365. [PMID: 38667041 PMCID: PMC11047382 DOI: 10.3390/antibiotics13040365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2024] [Revised: 04/09/2024] [Accepted: 04/11/2024] [Indexed: 04/29/2024] Open
Abstract
Clostridioides difficile infections (CDIs) continue to be a persistent healthcare concern despite newer antibiotic treatments, enhanced infection control practices, and preventive strategies focused on restoring the protective intestinal microbial barrier. Recent strides in gene sequencing research have identified many genes regulating diverse virulence factors for CDIs. These genes may be over- or under-expressed when triggered by various environmental and nutritional factors. The aims of this paper are to review the important genes involved in C. difficile pathogenesis and to identify modifiable environmental, nutritional, and other factors that may trigger the expression of these genes and thus offer new strategies to prevent CDIs.
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Affiliation(s)
- Zoe Masset
- INRS Armand-Frappier Health Biotechnology Research Centre, Research Laboratories in Sciences, 531 des Prairies Blvd, Laval, QC H7V 1B7, Canada; (Z.M.); (M.L.)
| | - Sathursha Gunaratnam
- Bio-K+, a Kerry Company, Preclinical Research Division, 495 Armand-Frappier Blvd, Laval, QC H7V 4B3, Canada; (S.G.); (M.M.)
| | - Mathieu Millette
- Bio-K+, a Kerry Company, Preclinical Research Division, 495 Armand-Frappier Blvd, Laval, QC H7V 4B3, Canada; (S.G.); (M.M.)
| | - Lynne V. McFarland
- Public Health Reserves Corps, Seattle, WA 98115, USA
- McFarland Consulting, Seattle, WA 98115, USA
| | - Monique Lacroix
- INRS Armand-Frappier Health Biotechnology Research Centre, Research Laboratories in Sciences, 531 des Prairies Blvd, Laval, QC H7V 1B7, Canada; (Z.M.); (M.L.)
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Wultańska D, Karpiński P, Piotrowski M, Pituch H. The Effect of Subinhibitory Concentration of Metronidazole on the Growth and Biofilm Formation on Toxigenic Clostridioides difficile Strains Belonging to Different Ribotypes. Pathogens 2023; 12:1244. [PMID: 37887760 PMCID: PMC10609937 DOI: 10.3390/pathogens12101244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 10/11/2023] [Accepted: 10/12/2023] [Indexed: 10/28/2023] Open
Abstract
Clostridioides difficile is a predominant nosocomial pathogen within the healthcare setting able to produce biofilms. Sub-minimum inhibitory concentrations (sub-MICs) of antibiotics trigger mechanisms affecting bacterial virulence, including increased adhesion and biofilm formation. The aim of this study was to investigate how sub-MICs of metronidazole affect the biofilm formation of C. difficile strains. We tested 14 reference and clinical C. difficile strains, including hypervirulent strains of RT027. The MICs of metronidazole for the tested strains were determined using the broth microdilution method. Biofilm formation was evaluated using confocal laser scanning microscopy. The C. difficile strains belonging to RT027 produced the highest amounts of biofilm. The results of confocal laser scanning microscopy showed that all the tested C. difficile strains developed larger biofilms with diversified architectures upon exposure to sub-MICs of metronidazole. In our study, we reveal that sub-MIC concentrations of metronidazole affect the biofilm formation of clinical and reference strains of C. difficile. Importantly, metronidazole induces biofilm formation via hypervirulent RT027 strains.
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Affiliation(s)
- Dorota Wultańska
- Department of Medical Microbiology, Medical University of Warsaw, 02-004 Warsaw, Poland; (P.K.); (M.P.); (H.P.)
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Johnstone M, Landgraf AD, Si A, Sucheck SJ, Self WT. Evaluation of Derivatives of (+)-Puupehenone against Clostridioides difficile and Other Gram-Positive Bacteria. ACS OMEGA 2022; 7:33511-33517. [PMID: 36157757 PMCID: PMC9494636 DOI: 10.1021/acsomega.2c04471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 08/24/2022] [Indexed: 06/16/2023]
Abstract
Patients receiving healthcare are at higher risk of acquiring healthcare-associated infections, which cause a significant number of illnesses and deaths. Most pathogens responsible for these infections are highly resistant to multiple antibiotics, prompting the need for discovery of new therapeutics to combat these evolved threats. We synthesized structural derivatives of (+)-puupehenone, a marine natural product, and observed growth inhibition of several clinically relevant Gram-positive bacteria, particularly Clostridioides difficile. The most potent compounds-(+)-puupehenone, 1, 15, 19, and 20-all inhibited C. difficile in the range of 2.0-4.0 μg/mL. Additionally, when present in the range of 1-8 μg/mL, a subset of active compounds-(+)-puupehenone, 1, 6, 15, and 20-greatly reduced the ability of C. difficile to produce exotoxins, which are required for disease in infected hosts. Our findings showcase a promising class of compounds for potential drug development against Gram-positive pathogens, such as C. difficile.
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Affiliation(s)
- Michael
A. Johnstone
- Burnett
School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32816-2364, United States
| | - Alexander D. Landgraf
- Department
of Chemistry and Biochemistry, University
of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United
States
| | - Anshupriya Si
- Department
of Chemistry and Biochemistry, University
of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United
States
| | - Steven J. Sucheck
- Department
of Chemistry and Biochemistry, University
of Toledo, 2801 West Bancroft Street, Toledo, Ohio 43606, United
States
| | - William T. Self
- Burnett
School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, Florida 32816-2364, United States
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Pal R, Seleem MN. Discovery of a novel natural product inhibitor of Clostridioides difficile with potent activity in vitro and in vivo. PLoS One 2022; 17:e0267859. [PMID: 35939437 PMCID: PMC9359557 DOI: 10.1371/journal.pone.0267859] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 04/17/2022] [Indexed: 11/22/2022] Open
Abstract
Clostridioides difficile infection is a global health threat and remains the primary cause of hospital-acquired infections worldwide. The burgeoning incidence and severity of infections coupled with high rates of recurrence have created an urgent need for novel therapeutics. Here, we report a novel natural product scaffold as a potential anticlostridial lead with antivirulence properties and potent activity both in vitro and in vivo. A whole cell phenotypic screening of 1,000 purified natural products identified 6 compounds with potent activity against C. difficile (minimum inhibitory concentration (MIC) range from 0.03 to 2 μg/ml). All these 6 compounds were non-toxic to human colorectal cells. The natural product compounds also inhibited the production of key toxins, TcdA and TcdB, the key virulence determinants of C. difficile infection pathology. Additionally, the compounds exhibited rapid bactericidal activity and were superior to the standard-of-care antibiotic vancomycin, in reducing a high inoculum of C. difficile in vitro. Furthermore, a murine model of C. difficile infection revealed that compound NP-003875 conferred 100% protection to the infected mice from clinical manifestations of the disease. Collectively, the current study lays the foundation for further investigation of the natural product NP-003875 as a potential therapeutic choice for C. difficile infection.
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Affiliation(s)
- Rusha Pal
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, United States of America
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Mohamed N. Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, Indiana, United States of America
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- Center for Emerging, Zoonotic and Arthropod-borne Pathogens, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- * E-mail:
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5
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Abstract
Large clostridial toxins (LCTs) are a family of bacterial exotoxins that infiltrate and destroy target cells. Members of the LCT family include Clostridioides difficile toxins TcdA and TcdB, Paeniclostridium sordellii toxins TcsL and TcsH, Clostridium novyi toxin TcnA, and Clostridium perfringens toxin TpeL. Since the 19th century, LCT-secreting bacteria have been isolated from the blood, organs, and wounds of diseased individuals, and LCTs have been implicated as the primary virulence factors in a variety of infections, including C. difficile infection and some cases of wound-associated gas gangrene. Clostridia express and secrete LCTs in response to various physiological signals. LCTs invade host cells by binding specific cell surface receptors, ultimately leading to internalization into acidified vesicles. Acidic pH promotes conformational changes within LCTs, which culminates in translocation of the N-terminal glycosyltransferase and cysteine protease domain across the endosomal membrane and into the cytosol, leading first to cytopathic effects and later to cytotoxic effects. The focus of this review is on the role of LCTs in infection and disease, the mechanism of LCT intoxication, with emphasis on recent structural work and toxin subtyping analysis, and the genomic discovery and characterization of LCT homologues. We provide a comprehensive review of these topics and offer our perspective on emerging questions and future research directions for this enigmatic family of toxins.
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Ye J, Chu AJ, Lin L, Chan ST, Harper R, Xiao M, Artsimovitch I, Zuo Z, Ma C, Yang X. Benzyl and benzoyl benzoic acid inhibitors of bacterial RNA polymerase-sigma factor interaction. Eur J Med Chem 2020; 208:112671. [PMID: 32920341 PMCID: PMC7680358 DOI: 10.1016/j.ejmech.2020.112671] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/26/2020] [Accepted: 07/13/2020] [Indexed: 02/08/2023]
Abstract
Transcription is an essential biological process in bacteria requiring a core enzyme, RNA polymerase (RNAP). Bacterial RNAP is catalytically active but requires sigma (σ) factors for transcription of natural DNA templates. σ factor binds to RNAP to form a holoenzyme which specifically recognizes a promoter, melts the DNA duplex, and commences RNA synthesis. Inhibiting the binding of σ to RNAP is expected to inhibit bacterial transcription and growth. We previously identified a triaryl hit compound that mimics σ at its major binding site of RNAP, thereby inhibiting the RNAP holoenzyme formation. In this study, we modified this scaffold to provide a series of benzyl and benzoyl benzoic acid derivatives possessing improved antimicrobial activity. A representative compound demonstrated excellent activity against Staphylococcus epidermidis with minimum inhibitory concentrations reduced to 0.5 μg/mL, matching that of vancomycin. The molecular mechanism of inhibition was confirmed using biochemical and cellular assays. Low cytotoxicity and metabolic stability of compounds demonstrated the potential for further studies.
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Affiliation(s)
- Jiqing Ye
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Adrian Jun Chu
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
| | - Lin Lin
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
| | - Shu Ting Chan
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China
| | - Rachel Harper
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China
| | - Min Xiao
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Irina Artsimovitch
- Department of Microbiology and the Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA
| | - Zhong Zuo
- School of Pharmacy, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China
| | - Cong Ma
- State Key Laboratory of Chemical Biology and Drug Discovery, Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China.
| | - Xiao Yang
- Department of Microbiology, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong SAR, China.
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Goneau LW, Delport J, Langlois L, Poutanen SM, Razvi H, Reid G, Burton JP. Issues beyond resistance: inadequate antibiotic therapy and bacterial hypervirulence. FEMS MICROBES 2020; 1:xtaa004. [PMID: 37333955 PMCID: PMC10117437 DOI: 10.1093/femsmc/xtaa004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/15/2020] [Indexed: 10/15/2023] Open
Abstract
The administration of antibiotics while critical for treatment, can be accompanied by potentially severe complications. These include toxicities associated with the drugs themselves, the selection of resistant organisms and depletion of endogenous host microbiota. In addition, antibiotics may be associated with less well-recognized complications arising through changes in the pathogens themselves. Growing evidence suggests that organisms exposed to antibiotics can respond by altering the expression of toxins, invasins and adhesins, as well as biofilm, resistance and persistence factors. The clinical significance of these changes continues to be explored; however, it is possible that treatment with antibiotics may inadvertently precipitate a worsening of the clinical course of disease. Efforts are needed to adjust or augment antibiotic therapy to prevent the transition of pathogens to hypervirulent states. Better understanding the role of antibiotic-microbe interactions and how these can influence disease course is critical given the implications on prescription guidelines and antimicrobial stewardship policies.
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Affiliation(s)
- Lee W Goneau
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
- Lawson Health Research Institute, 268 Grosvenor St, London, Ontario, N6A 4V2 Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto,1 King's College Cir, Toronto, ON M5S 1A8 Ontario, Canada
| | - Johannes Delport
- Department of Pathology, London Health Sciences Center - Victoria Hospital, 800 Commissioners Rd E, London, Ontario, Canada N6A 5W9
| | - Luana Langlois
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
| | - Susan M Poutanen
- Department of Laboratory Medicine and Pathobiology, University of Toronto,1 King's College Cir, Toronto, ON M5S 1A8 Ontario, Canada
- Department of Medicine, University of Toronto, 1 King's College Cir, Toronto, ON M5S 1A8 Toronto, Ontario, Canada
- Department of Microbiology, University Health Network and Sinai Health, 190 Elizabeth St. Toronto, ON M5G 2C4, Ontario, Canada
| | - Hassan Razvi
- Lawson Health Research Institute, 268 Grosvenor St, London, Ontario, N6A 4V2 Canada
- Division of Urology, Department of Surgery, Western University, 1151 Richmond St, London, Ontario, N6A 3K7 Canada
| | - Gregor Reid
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
- Lawson Health Research Institute, 268 Grosvenor St, London, Ontario, N6A 4V2 Canada
- Division of Urology, Department of Surgery, Western University, 1151 Richmond St, London, Ontario, N6A 3K7 Canada
| | - Jeremy P Burton
- Department of Microbiology and Immunology, Western University, London, Ontario, Canada
- Lawson Health Research Institute, 268 Grosvenor St, London, Ontario, N6A 4V2 Canada
- Division of Urology, Department of Surgery, Western University, 1151 Richmond St, London, Ontario, N6A 3K7 Canada
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Yang J, Yang H. Antibacterial Activity of Bifidobacterium breve Against Clostridioides difficile. Front Cell Infect Microbiol 2019; 9:288. [PMID: 31440478 PMCID: PMC6693512 DOI: 10.3389/fcimb.2019.00288] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 07/26/2019] [Indexed: 12/17/2022] Open
Abstract
Bifidobacterium breve (YH68) is widely used in the fields of food fermentation and biomedicine. In this study, we explored the antibacterial activity of the cell free culture supernatant (CFCS) of YH68 against Clostridioides difficile ATCC 9689 (CD) by measuring multiple indexes, including the growth, spores production, toxin A/B production, and the expression levels of the tcdA and tcdB genes of CD. In addition, we examined the changes in major cellular functional groups, structures, permeability, integrity, and the proton motive force (PMF) of the cytoplasmic membrane. The results showed that double-dilution ratio of YH68-CFCS (3 × 109 CFU/mL) was the MIC value. The cell density, spores production, and the toxin production of CD treated with YH68-CFCS were lower than that of the control (p < 0.05). In addition, the gene expression levels of tcdA and tcdB in CD treated with YH68-CFCS were significant downregulated (p < 0.05). Marked differences were observed in the cell membrane and cell wall by a FT-IR spectroscopy and SEM. Analysis of the cell membrane permeability and integrity of the CD cells revealed that YH68-CFCS induced the leakage of a large amount of intracellular K+, inorganic phosphate, ATP, nucleic acids and proteinaceous substances. Furthermore, PMF analysis indicated that there was a significant change in Δψ and ΔpH. These findings demonstrated that the antibacterial activity of YH68-CFCS against CD involved the inhibition of growth, spore production, toxin production, and virulence genes expression; a consumption of PMF in the cytoplasmic membrane, the formation of pore in the cell membrane, together with the enhanced cell membrane permeability; and, eventually, cell completely disintegration.
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Affiliation(s)
- Jingpeng Yang
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hong Yang
- State Key Laboratory of Microbial Metabolism, School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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9
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Spore Production of Toxigenic and Non-toxigenic Clostridium difficile Isolates in Sub-MIC of Vancomycin, Clindamycin, and Ceftazidime. Jundishapur J Microbiol 2019. [DOI: 10.5812/jjm.57905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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10
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Lee W, Woo ER, Lee DG. Effect of apigenin isolated from Aster yomena against Candida albicans: apigenin-triggered apoptotic pathway regulated by mitochondrial calcium signaling. JOURNAL OF ETHNOPHARMACOLOGY 2019; 231:19-28. [PMID: 30408533 DOI: 10.1016/j.jep.2018.11.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/22/2018] [Accepted: 11/03/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Aster yomena, a perennial herb that grows mainly in South Korea, has been employed in the traditional temple food for antibiotic efficacy. Recently, it was reported that apigenin isolated from A. yomena has a physical antifungal mechanism targeting membrane against Candida albicans. AIM OF THE STUDY Our study aimed to investigate the biochemical responses underlying the antifungal activity of apigenin isolated from A. yomena due to lack studies reporting the investigation of intracellular responses of apigenin in C. albicans. MATERIALS AND METHODS Apigenin was isolated from the aerial parts of A. yomena. To evaluate apigenin-induced inhibitory effects and membrane damages, the measurement of the cell viability assay and the flux of cytosolic components were performed with at various concentrations. Intracellular external potassium and calcium levels were assayed by an ion-selective electrode meter, Fura2-AM and Rhod2-AM, respectively. Mitochondrial dysfunctions were analyzed by using JC-1, Mitotracker Green FM, and MitoSOX Red dye. H2DCFDA, glutathione, and MDA assay were used to detect oxidative damage. Also, flow cytometry was carried out to detect apoptotic hallmarks using Annexin V-PI, TUNEL, and FITC-VAD-FMK staining. Tetraethylammoniumchloride (TEA), Ruthenium red (RR), and N-acetylcysteine (NAC) were used as a potassium channel blocker, mitochondrial calcium uptake inhibitor, and reactive oxygen species (ROS) scavenger, respectively. RESULTS We confirmed that there was no decrease of cell survival percentages in crude extracts of A. yomena treatment, however, only isolated apigenin has the antifungal effect in C. albicans. Apigenin triggered a dose-dependent mitochondrial calcium uptake followed by mitochondrial dysfunction, loss of the membrane potential and an increase in the mitochondrial mass and ROS. Apigenin also induced intracellular redox imbalance as indicated by the ROS accumulation, glutathione oxidation, and lipid peroxidation. Interestingly, NAC failed the restore the mitochondrial calcium levels and thus alleviate the mitochondrial damages, however, RR reduced the apigenin-induced redox imbalance. Furthermore, apigenin induced apoptosis activation marked by the phosphatidylserine exposure, DNA fragmentation, and caspase activation. The pro-apoptotic effect of apigenin was counteracted by RR and NAC pretreatment. In particular, RR significantly reduced the pro-apoptotic responses. CONCLUSIONS Apigenin isolated from A. yomena induced mitochondrial-mediated apoptotic pathway, and mitochondrial calcium signaling is main factor in its pathway in C. albicans.
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Affiliation(s)
- Wonjong Lee
- School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea.
| | - Eun-Rhan Woo
- College of Pharmacy, Chosun University, 375 Seosukdong, Donggu, Gwangju 61452, Republic of Korea.
| | - Dong Gun Lee
- School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu 41566, Republic of Korea.
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Yang J, Yang H. Effect of Bifidobacterium breve in Combination With Different Antibiotics on Clostridium difficile. Front Microbiol 2018; 9:2953. [PMID: 30564210 PMCID: PMC6288195 DOI: 10.3389/fmicb.2018.02953] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 11/16/2018] [Indexed: 12/18/2022] Open
Abstract
While combinations of probiotics with antibiotics have exhibited beneficial and adverse effects in the treatment of Clostridium difficile infection (CDI), no substantive explanation has been provided for these effects. In this study, C. difficile ATCC 9689 (CD) was treated with Bifidobacterium breve (YH68) in combination with five different antibiotics to explore the effects of the different combinations on C. difficile. Cell-free culture supernatant (CFCS) of YH68 was combined with metronidazole (MTR), vancomycin (VAN), clindamycin (CLI), ceftazidime (CAZ) or ampicillin (AMP) to treat CD. The plate counting method was used to determine the growth and spore production of CD, and cell damage was assessed by the measurement of extracellular ATP levels with a luminescence-based kit. The production of toxin A/B was measured with an ELISA kit. The gene expression levels of tcdA and tcdB in CD were evaluated by real-time qPCR. The CFCS of YH68 (3 × 109 CFU/mL) at 0.25 times the minimal inhibitory concentration (MIC) (0.25YH68) in combination with the five antibiotics exerted stronger inhibitory effects on the growth and spore production of CD than the same antibiotics in the absence of 0.25YH68, except 0.25YH68&MTR&, 0.25YH68&MTR&CAZ, and 0.25YH68&VAN&CLI. However, treatment with 0.25YH68&VAN, 0.25YH68&, 0.25YH68&MTR&CAZ, 0.25YH68&VAN&CAZ, 0.25YH68&VAN&, and 0.25YH68&CAZ& resulted in increased cell damage. In addition, the different combinations, except 0.25YH68&CLI, 0.25YH68&MTR& and 0.25YH68&VAN&CLI, dramatically reduced the production of toxin A/B in comparison with the effects of the same antibiotics in the absence of 0.25YH68. The gene expression levels of tcdA and tcdB in CD were lowered upon treatment with 0.25YH68 in combination with MTR, CLI, CAZ, MTR&CAZ, MTR&, CLI&CAZ, and CLI&, whereas the levels were enhanced by 0.25YH68 in combination with VAN, AMP, MTR&CLI, VAN&CLI, VAN&, and CAZ&. In summary, YH68 in combination with specific antibiotics could enhance the inhibitory effects of antibiotics against CD. In addition, the antagonistic effects between some antibiotics could be weakened by YH68.
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Affiliation(s)
| | - Hong Yang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
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12
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Aldape MJ, Rice SN, Field KP, Bryant AE, Stevens DL. Sub-lethal doses of surotomycin and vancomycin have similar effects on Clostridium difficile virulence factor production in vitro. J Med Microbiol 2018; 67:1689-1697. [PMID: 30307842 DOI: 10.1099/jmm.0.000852] [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] [Indexed: 01/27/2023] Open
Abstract
PURPOSE Clostridium difficile is an anaerobic spore-forming bacterial pathogen that causes a spectrum of illness severity ranging from mild diarrhoea to severe life-threatening pseudomembranous colitis. C. difficile infection (CDI) is antibiotic-associated and primarily mediated by two exotoxins, Toxins A and B. We and others have shown that some antibiotics stimulate Toxin A and B production by C. difficile in a strain-specific manner. Still, the effects of newer anti-C. difficile antibiotics on this process and spore formation remain to be investigated. METHODOLOGY Surotomycin (formally CB-183,315) is a novel, minimally absorbed, narrow-spectrum antibiotic. We determined the effects of surotomycin on C. difficile growth, toxin production and sporulation in historical and BI/NAP1/027 epidemic strains of C. difficile.Results/Key findings. While antibiotic free controls showed toxin production during the stationary phase growth, all strains exposed to sub-inhibitory concentrations of surotomycin and vancomycin demonstrated increased TcdA and TcdB production during early (log phase) growth by all strains. However, this effect was not observed at 24 or 48 h post-treatment by any of the C. difficile strains exposed to either antibiotic. Additionally, all doses of surotomycin and vancomycin suppressed spore formation in all tested strains. CONCLUSION In summary, these findings demonstrate that surotomycin and vancomycin have similar effects on exotoxin production and sporulation by C. difficile in vitro. Furthermore, since spores contribute to recurrent infection, the ability of surotomycin to suppress spore formation may explain its ability to disrupt the reinfection cycle in the clinical setting.
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Affiliation(s)
- Michael John Aldape
- 1Department of Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Boise, ID, USA
| | - Savannah Nicole Rice
- 1Department of Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Boise, ID, USA
| | - Kevin Patrick Field
- 1Department of Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Boise, ID, USA
| | - Amy Evelyn Bryant
- 1Department of Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Boise, ID, USA.,2University of Washington School of Medicine, Seattle, WA, USA
| | - Dennis Leroy Stevens
- 1Department of Veterans Affairs Medical Center, Department of Veterans Affairs Medical Center, Boise, ID, USA.,2University of Washington School of Medicine, Seattle, WA, USA
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13
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Stewart DB. Anti-Sense Antibiotic Agents as Treatment for Bacterial Infections. Surg Infect (Larchmt) 2018; 19:831-835. [PMID: 30256744 DOI: 10.1089/sur.2018.200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background: Conventional antibiotic agents are overused, leading to decreased efficacy because of a rising incidence in antimicrobial resistance. Further, conventional antibiotic agents result in widespread effects to human microbiota, which can lead directly to adverse events such as Clostridium difficile infection. Methods: This review provides a narrative summary of anti-sense therapies, an approach to managing bacterial infections by pursuing specific molecular targets that disrupt the flow of information from deoxyribonucleic acid to ribonucleic acid to protein, leading to the loss of bacterial functions. Included in this article is the rationale for this approach, the current data supporting its further investigation, and the challenges and future directions in this area of research. Results: There is a compelling proof-of-concept against both gram-positive and gram-negative organisms to commend the use of modified anti-sense oligonucleotides as antimicrobial therapy. There are data demonstrating that anti-sense therapies are capable of killing bacteria, silencing antimicrobial resistance mechanisms to restore sensitivity to conventional antibiotic agents, and to target virulence pathways such as biofilm production. Further, these drugs have a significantly greater degree of organismal specificity, limiting antibiotic-associated diarrhea and lowering the risk of antibiotic-related infections such as C. difficile infection. Conclusions: Anti-sense therapies show promise as a new class of antibiotic agents, providing molecular precision that leads to specific targeting of bacterial species and bacterial functions, including virulence mechanisms beyond the reach of current antibiotic agents. Further, changing the sequence of an anti-sense oligonucleotide provides a method of dealing with antimicrobial resistance that is more time- and cost-flexible than the available options with current conventional antibiotic agents.
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Affiliation(s)
- David B Stewart
- Department of Surgery, Section of Colorectal Surgery, University of Arizona , Tucson, Arizona
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14
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Gu H, Shi K, Liao Z, Qi H, Chen S, Wang H, Li S, Ma Y, Wang J. Time-resolved transcriptome analysis of Clostridium difficile R20291 response to cysteine. Microbiol Res 2018; 215:114-125. [PMID: 30172297 DOI: 10.1016/j.micres.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 05/21/2018] [Accepted: 07/07/2018] [Indexed: 01/05/2023]
Abstract
The incidence of Clostridium difficile infection has been steadily rising over the past decade. The increase in the rate of incidence is associated with the specific NAP1/BI/027 strains which are "hypervirulent" and have led to several large outbreaks since their emergence. However, the relation between these outbreaks and virulence regulation mechanisms remains unclear. It has been reported that the major virulence factor TcdA and TcdB in C. difficile could be repressed by cysteine. Here, we investigated the functional and virulence-associated regulation of C. difficile R20291 response to cysteine by using a time-resolved genome-wide transcriptome analysis. Dramatic changes of gene expression in C. difficile revealed functional processes related to transport, metabolism, and regulators in the presence of cysteine during different phases of growth. Flagellar and ribosomal genes were significantly down-regulated in long-term response to cysteine. Many NAP1/BI/027- specific genes were also modulated by cysteine. In addition, cdsB inactivation in C. difficile R20291 could remove the repression of toxin synthesis but could not remove the repression of butyrate production in the presence of cysteine. This suggests that toxin synthesis and butyrate production might have different regulatory controls in response to cysteine. Altogether, our research provides important insights into the regulatory mechanisms of C. difficile response to cysteine.
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Affiliation(s)
- Huawei Gu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Kan Shi
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Zhengping Liao
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Haonan Qi
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shuyi Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Haiying Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shan Li
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Yi Ma
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Jufang Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China.
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15
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Abstract
Surface-attached colonies of bacteria known as biofilms play a major role in the pathogenesis of device-related infections. Biofilm colonies are notorious for their resistance to suprainhibitory concentrations of antibiotics. Numerous studies have shown that subminimal inhibitory concentrations of some antibiotics can act as agonists of bacterial biofilm formation in vitro, a process that may have clinical relevance. This article reviews studies demonstrating that low-dose antibiotics induce bacterial biofilm formation. These studies have provided important information about the regulation of biofilm formation and the signaling pathways involved in global gene regulation in response to cell stressors. It is still unclear whether antibiotic-induced biofilm formation contributes to the inconsistent success of antimicrobial therapy for device infections.
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16
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Lee W, Lee DG. Potential role of potassium and chloride channels in regulation of silymarin-induced apoptosis in Candida albicans. IUBMB Life 2018; 70:197-206. [PMID: 29356280 DOI: 10.1002/iub.1716] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 12/29/2017] [Indexed: 12/17/2022]
Abstract
Silymarin, which is derived from the seeds of Silybum marianum, has been widely used to prevent and treat liver diseases. In our previous study, we reported that at concentrations above the minimal inhibitory concentration (MIC), silymarin exhibited antifungal activity against Candida albicans by targeting its plasma membrane. However, the antifungal mechanism at concentration below the MIC remains unknown. Therefore, we aimed to determine the underlying mechanism of antifungal effects of silymarin at concentration below the MIC. To evaluate the inhibitory effects on the ion channels, C. albicans cells were separately pretreated with potassium and chloride channel blockers. The antifungal activity of silymarin at sub-MIC was affected by the ion channel blockers. Potassium channel blockade inhibited the antifungal effects, whereas chloride channel blockade slightly enhanced these effects. Subsequently, we found that silymarin induced disturbances in calcium homeostasis via the cytosolic and mitochondrial accumulation of calcium. Furthermore, apoptotic responses, such as phosphatidylserine exposure, loss of mitochondrial membrane potential (MMP), DNA damage, and caspase activation were induced in response to silymarin treatment. The increases in intracellular calcium level and pro-apoptotic changes were prevented when potassium ion channels were blocked. In contrast, these changes were enhanced upon chloride channels blockade; however, this did not affect the intracellular calcium levels and MMP loss. Thus, we showed that silymarin treatment at concentration below the MIC induced apoptosis in C. albicans; additionally, ion channels contributed these effects. © 2018 IUBMB Life, 70(3):197-206, 2018.
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Affiliation(s)
- Wonjong Lee
- School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu, Republic of Korea
| | - Dong Gun Lee
- School of Life Sciences, BK 21 Plus KNU Creative BioResearch Group, College of Natural Sciences, Kyungpook National University, 80 Daehakro, Bukgu, Daegu, Republic of Korea
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17
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Shun-Mei E, Zeng JM, Yuan H, Lu Y, Cai RX, Chen C. Sub-inhibitory concentrations of fluoroquinolones increase conjugation frequency. Microb Pathog 2017; 114:57-62. [PMID: 29174700 DOI: 10.1016/j.micpath.2017.11.036] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 11/21/2017] [Accepted: 11/22/2017] [Indexed: 02/08/2023]
Abstract
Bacteria are subjected to sub-minimal inhibitory concentrations (sub-MIC) of antibiotics in various niches where the low-dosage treatment plays a key role in antibiotic resistance selection. However, the mechanism of sub-MIC of antibiotics on the resistant gene transfer is largely unknown. Here, we used Escherichia coli SM10λpir in which the RP4 plasmid was chromosomally-integrated as the donor strain, to investigate the effects of sub-MIC of Ciprofloxacin(Cip) or Levofloxacin(Lev) on conjugational transfer of mobilisable plasmid-pUCP24T from SM10λpir to Pseudomonas aeruginosa. The results showed that the transfer frequency was significantly increased by treating E. coli with sub-MIC of Cip or Lev. To investigate the molecular mechanisms, complete transcriptome sequencing was performed. We found that the sub-MIC of Cip or Lev enhanced the expression of several genes on the RP4 plasmid, which was consistent with the conjugation efficiency. Moreover, the expression of genes associated with SOS response in donor SM10λpir was increased, but had no correlation with conjugation efficiency. These findings suggested that sub-MIC of Cip or Lev may promote conjugational transfer by up-regulating the expression of conjugation associated genes via an SOS-independent mechanism.
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Affiliation(s)
- E Shun-Mei
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
| | - Jian-Ming Zeng
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
| | - Hui Yuan
- Department of Gastroenterology, People Hospital, Hubei University of Medicine, Shiyan, China.
| | - Yang Lu
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
| | - Ren-Xin Cai
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
| | - Cha Chen
- Department of Laboratory Medicine, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
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18
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Grześkowiak Ł, Martínez-Vallespín B, Dadi TH, Radloff J, Amasheh S, Heinsen FA, Franke A, Reinert K, Vahjen W, Zentek J, Pieper R. Formula Feeding Predisposes Neonatal Piglets to Clostridium difficile Gut Infection. J Infect Dis 2017; 217:1442-1452. [DOI: 10.1093/infdis/jix567] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 12/20/2022] Open
Affiliation(s)
| | | | - Temesgen H Dadi
- Department of Mathematics and Computer Science, Institute of Computer Science, Kiel, Germany
- Max Planck Institute for Molecular Genetics, Berlin, Kiel, Germany
| | - Judith Radloff
- Institute of Veterinary Physiology, Freie Universität Berlin, Kiel, Germany
| | - Salah Amasheh
- Institute of Veterinary Physiology, Freie Universität Berlin, Kiel, Germany
| | - Femke-Anouska Heinsen
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, University Hospital Schleswig Holstein, Kiel, Germany
| | - Andre Franke
- Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, University Hospital Schleswig Holstein, Kiel, Germany
| | - Knut Reinert
- Department of Mathematics and Computer Science, Institute of Computer Science, Kiel, Germany
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19
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Aldape MJ, Packham AE, Heeney DD, Rice SN, Bryant AE, Stevens DL. Fidaxomicin reduces early toxin A and B production and sporulation in Clostridium difficile
in vitro. J Med Microbiol 2017; 66:1393-1399. [DOI: 10.1099/jmm.0.000580] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- Michael J. Aldape
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
| | - Aaron E. Packham
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
- Present address: Kirksville College of Osteopathic Medicine, Kirksville, MO, USA
| | - Dustin D. Heeney
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
- Present address: The University of California, Davis, CA, USA
| | - Savannah N. Rice
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
| | - Amy E. Bryant
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
- University of Washington School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA
| | - Dennis L. Stevens
- Department of Veterans Affairs Medical Center, 500 W. Fort St, Boise, ID 83712, USA
- University of Washington School of Medicine, 1959 NE Pacific St, Seattle, WA 98195, USA
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20
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Zarandi ER, Mansouri S, Nakhaee N, Sarafzadeh F, Moradi M. Effect of sub-MIC of vancomycin and clindamycin alone and in combination with ceftazidime on Clostridium difficile surface layer protein A (slpA) gene expression. Microb Pathog 2017; 111:163-167. [PMID: 28867619 DOI: 10.1016/j.micpath.2017.08.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Revised: 08/30/2017] [Accepted: 08/30/2017] [Indexed: 11/15/2022]
Abstract
Clostridium difficile (C.difficile) infection is often established in the presence of antibiotics and probably antibiotics can influence surface layer protein A (slpA) expression as a colonization factor. The aim of this study is to evaluate the effect of vancomycin (VAN), clindamycin (CLI) alone and in combination with ceftazidime (CAZ) on slpA gene expression to determine whether such antibiotics can have any effect on slpA expression. About ∼106 CFU/mL was inoculated to medium containing an appropriate concentration of antibiotics alone and in combination. After 24 and 48 h incubation under anaerobic condition, 3 mL of culture was excluded and centrifuged in 8000 × g per 3 min. The pellet was washed and used for RNA extraction. The RNA extraction, Dnase I treatment and cDNA synthesis was performed by RNA extraction, Dnase I, and cDNA synthesis kits, respectively. The real-time PCR were carried out by sybrGreen methods and data were analyzed based on comparative ΔΔCT. All antibiotics alone and in combination, except VAN/CAZ in clinical isolate, decreased the level of slpA gene expression in the 24-h incubation. While the expression profile of slpA was different in the 48-h incubation period. The VAN and CLI decreased the slpA expression, although the template of expression is closed to control medium. CAZ alone and in combination increased slpA expression. C. difficile may down-regulate slpA expression in the early stages of growth in sub-inhibitory concentration of antibiotics. But, over time C. difficile increases or over expresses the slpA expression level. Consequently C. difficile binds strongly to epithelial cells and continues to survive in the presence of sub-MIC concentration of antibiotics. This effect is observed especially with regard to CAZ and probably other third generation cephalosporins or in combination therapy with VAN or CLI, which are prescribed in the clinic. CAZ can interfere with the anti-down regulatory feature of VAN, CLI, and maybe other antibiotics.
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Affiliation(s)
- Ebrahim Rezazadeh Zarandi
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Shahla Mansouri
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Nouzar Nakhaee
- Department of Community Medicine, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Farhad Sarafzadeh
- Department of Infectious Diseases, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Moradi
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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21
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Prezioso SM, Brown NE, Goldberg JB. Elfamycins: inhibitors of elongation factor-Tu. Mol Microbiol 2017; 106:22-34. [PMID: 28710887 DOI: 10.1111/mmi.13750] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2017] [Indexed: 01/26/2023]
Abstract
Elfamycins are a relatively understudied group of antibiotics that target the essential process of translation through impairment of EF-Tu function. For the most part, the utility of these compounds has been as laboratory tools for the study of EF-Tu and the ribosome, as their poor pharmacokinetic profile and solubility has prevented implementation as therapeutic agents. However, due to the slowing of the antibiotic pipeline and the rapid emergence of resistance to approved antibiotics, this group is being reconsidered. Some researchers are using screens for novel naturally produced variants, while others are making directed, systematic chemical improvements on publically disclosed compounds. As an example of the latter approach, a GE2270 A derivative, LFF571, has completed phase 2 clinical trials, thus demonstrating the potential for elfamycins to become more prominent antibiotics in the future.
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Affiliation(s)
- Samantha M Prezioso
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA.,Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nicole E Brown
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Joanna B Goldberg
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA.,Emory+Children's Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, GA 30322, USA
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22
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Zarandi ER, Mansouri S, Nakhaee N, Sarafzadeh F, Moradi M. Toxin production of Clostridium difficile in sub-MIC of vancomycin and clindamycin alone and in combination with ceftazidime. Microb Pathog 2017; 107:249-253. [PMID: 28286152 DOI: 10.1016/j.micpath.2017.03.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/26/2017] [Accepted: 03/06/2017] [Indexed: 02/01/2023]
Abstract
Toxin production in Clostridium difficile (C. difficile) is a key process for induction of diarrhea. Several factors such as sub-MIC of antibiotics impact on toxin production. The aim of this research is investigation of sub-minimum inhibitory concentration (sub-MIC) of vancomycin (VAN), clindamycin (CLI) separately and in combination with ceftazidime (CAZ) on toxin production in C. difficile. About ∼106 colony forming units (CFU) from 18-h culture of C. difficile ATCC 9689 and clinical isolates A+/B+/CTD-, were cultured anaerobically in the pre-reduced medium with appropriate concentration of separated and in combination antibiotics. After 24 and 48 h, 1 mL of culture was removed, centrifuged and the supernatant stored at-70 °C for later use. The evaluation of toxin production was carried out by the ELISA technique. All antibiotics alone and in combination formats inhibited toxin production over a period of 24 h. This effect is also observed in presence of VAN and CLI during a period of 48 h. Over a 4 h period, CAZ increased toxin production alone and in combination, especially with CLI. The data showed VAN and CLI decrease the level of toxins. In contrast, the CAZ not only increases the level of produced toxin, but also can interfere with VAN and CLI. Based on the results, combination therapy which is performed for treatment or prevention of other infections may cause toxin production and probably the severity of C. difficile AAD to increase.
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Affiliation(s)
- Ebrahim Rezazadeh Zarandi
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Shahla Mansouri
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Nouzar Nakhaee
- Department of Community Medicine, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Farhad Sarafzadeh
- Department of Infectious Diseases, Afzalipour Hospital, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Moradi
- Department of Microbiology and Virology, Faculty of Medicine, Kerman University of Medical Sciences, Kerman, Iran.
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23
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Kashaf SS, Angione C, Lió P. Making life difficult for Clostridium difficile: augmenting the pathogen's metabolic model with transcriptomic and codon usage data for better therapeutic target characterization. BMC SYSTEMS BIOLOGY 2017; 11:25. [PMID: 28209199 PMCID: PMC5314682 DOI: 10.1186/s12918-017-0395-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 01/13/2017] [Indexed: 11/10/2022]
Abstract
BACKGROUND Clostridium difficile is a bacterium which can infect various animal species, including humans. Infection with this bacterium is a leading healthcare-associated illness. A better understanding of this organism and the relationship between its genotype and phenotype is essential to the search for an effective treatment. Genome-scale metabolic models contain all known biochemical reactions of a microorganism and can be used to investigate this relationship. RESULTS We present icdf834, an updated metabolic network of C. difficile that builds on iMLTC806cdf and features 1227 reactions, 834 genes, and 807 metabolites. We used this metabolic network to reconstruct the metabolic landscape of this bacterium. The standard metabolic model cannot account for changes in the bacterial metabolism in response to different environmental conditions. To account for this limitation, we also integrated transcriptomic data, which details the gene expression of the bacterium in a wide array of environments. Importantly, to bridge the gap between gene expression levels and protein abundance, we accounted for the synonymous codon usage bias of the bacterium in the model. To our knowledge, this is the first time codon usage has been quantified and integrated into a metabolic model. The metabolic fluxes were defined as a function of protein abundance. To determine potential therapeutic targets using the model, we conducted gene essentiality and metabolic pathway sensitivity analyses and calculated flux control coefficients. We obtained 92.3% accuracy in predicting gene essentiality when compared to experimental data for C. difficile R20291 (ribotype 027) homologs. We validated our context-specific metabolic models using sensitivity and robustness analyses and compared model predictions with literature on C. difficile. The model predicts interesting facets of the bacterium's metabolism, such as changes in the bacterium's growth in response to different environmental conditions. CONCLUSIONS After an extensive validation process, we used icdf834 to obtain state-of-the-art predictions of therapeutic targets for C. difficile. We show how context-specific metabolic models augmented with codon usage information can be a beneficial resource for better understanding C. difficile and for identifying novel therapeutic targets. We remark that our approach can be applied to investigate and treat against other pathogens.
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Affiliation(s)
- Sara Saheb Kashaf
- Computer Laboratory, University of Cambridge, 15 JJ Thomson Avenue, Cambridge, CB3 0FD UK
| | - Claudio Angione
- Department of Computer Science and Information Systems, Teesside University, Borough road, Middlesbrough, TS1 3BA UK
| | - Pietro Lió
- Computer Laboratory, University of Cambridge, 15 JJ Thomson Avenue, Cambridge, CB3 0FD UK
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24
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Martin-Verstraete I, Peltier J, Dupuy B. The Regulatory Networks That Control Clostridium difficile Toxin Synthesis. Toxins (Basel) 2016; 8:E153. [PMID: 27187475 PMCID: PMC4885068 DOI: 10.3390/toxins8050153] [Citation(s) in RCA: 104] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 05/03/2016] [Accepted: 05/05/2016] [Indexed: 12/19/2022] Open
Abstract
The pathogenic clostridia cause many human and animal diseases, which typically arise as a consequence of the production of potent exotoxins. Among the enterotoxic clostridia, Clostridium difficile is the main causative agent of nosocomial intestinal infections in adults with a compromised gut microbiota caused by antibiotic treatment. The symptoms of C. difficile infection are essentially caused by the production of two exotoxins: TcdA and TcdB. Moreover, for severe forms of disease, the spectrum of diseases caused by C. difficile has also been correlated to the levels of toxins that are produced during host infection. This observation strengthened the idea that the regulation of toxin synthesis is an important part of C. difficile pathogenesis. This review summarizes our current knowledge about the regulators and sigma factors that have been reported to control toxin gene expression in response to several environmental signals and stresses, including the availability of certain carbon sources and amino acids, or to signaling molecules, such as the autoinducing peptides of quorum sensing systems. The overlapping regulation of key metabolic pathways and toxin synthesis strongly suggests that toxin production is a complex response that is triggered by bacteria in response to particular states of nutrient availability during infection.
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Affiliation(s)
- Isabelle Martin-Verstraete
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
- UFR Sciences du vivant, University Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, Paris 75015, France.
| | - Johann Peltier
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
| | - Bruno Dupuy
- Laboratoire Pathogenèse des Bactéries Anaérobes, Department of Microbiology, Institut Pasteur, 25 rue du Dr Roux Paris, Paris 75015, France.
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25
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Baines SD, Wilcox MH. Antimicrobial Resistance and Reduced Susceptibility in Clostridium difficile: Potential Consequences for Induction, Treatment, and Recurrence of C. difficile Infection. Antibiotics (Basel) 2015; 4:267-98. [PMID: 27025625 PMCID: PMC4790285 DOI: 10.3390/antibiotics4030267] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/02/2015] [Accepted: 07/03/2015] [Indexed: 12/11/2022] Open
Abstract
Clostridium difficile infection (CDI) remains a substantial burden on healthcare systems and is likely to remain so given our reliance on antimicrobial therapies to treat bacterial infections, especially in an aging population in whom multiple co-morbidities are common. Antimicrobial agents are a key component in the aetiology of CDI, both in the establishment of the infection and also in its treatment. The purpose of this review is to summarise the role of antimicrobial agents in primary and recurrent CDI; assessing why certain antimicrobial classes may predispose to the induction of CDI according to a balance between antimicrobial activity against the gut microflora and C. difficile. Considering these aspects of CDI is important in both the prevention of the infection and in the development of new antimicrobial treatments.
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Affiliation(s)
- Simon D Baines
- Department of Biological and Environmental Sciences, School of Life and Medical Sciences, University of Hertfordshire, Hatfield AL10 9AB, UK.
| | - Mark H Wilcox
- Leeds Institute of Biomedical and Clinical Sciences, Faculty of Medicine and Health, University of Leeds, Leeds LS2 9JT, UK.
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, The General Infirmary, Leeds LS1 3EX, UK.
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26
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Sachdeva M, Leeds JA. Subinhibitory concentrations of LFF571 reduce toxin production by Clostridium difficile. Antimicrob Agents Chemother 2015; 59:1252-7. [PMID: 25512411 PMCID: PMC4335859 DOI: 10.1128/aac.04436-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/07/2014] [Indexed: 01/05/2023] Open
Abstract
LFF571 is a novel semisynthetic thiopeptide antibacterial that is undergoing investigation for safety and efficacy in patients with moderate Clostridium difficile infections. LFF571 inhibits bacterial protein synthesis by interacting with elongation factor Tu (EF-Tu) and interrupting complex formation between EF-Tu and aminoacyl-tRNA. Given this mechanism of action, we hypothesized that concentrations of LFF571 below those necessary to inhibit bacterial growth would reduce steady-state toxin levels in C. difficile cultures. We investigated C. difficile growth and toxin A and B levels in the presence of LFF571, fidaxomicin, vancomycin, and metronidazole. LFF571 led to strain-dependent effects on toxin production, including decreased toxin levels after treatment with subinhibitory concentrations, and more rapid declines in toxin production than in inhibition of colony formation. Fidaxomicin, which is an RNA synthesis inhibitor, conferred a similar pattern to LFF571 with respect to toxin levels versus viable cell counts. The incubation of two toxigenic C. difficile strains with subinhibitory concentrations of vancomycin, a cell wall synthesis inhibitor, increased toxin levels in the supernatant over those of untreated cultures. A similar phenomenon was observed with one metronidazole-treated strain of C. difficile. These studies indicate that LFF571 and fidaxomicin generally result in decreased C. difficile toxin levels in culture supernatants, whereas treatment of some strains with vancomycin or metronidazole had the potential to increase toxin levels. Although the relevance of these findings remains to be studied in patients, reducing toxin levels with sub-growth-inhibitory concentrations of an antibiotic is hypothesized to be beneficial in alleviating symptoms.
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Affiliation(s)
- Meena Sachdeva
- Novartis Institutes for BioMedical Research, Infectious Disease Area, Emeryville, California, USA
| | - Jennifer A Leeds
- Novartis Institutes for BioMedical Research, Infectious Disease Area, Emeryville, California, USA
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Su YH, Warren CA, Guerrant R, Swami NS. Dielectrophoretic monitoring and interstrain separation of intact Clostridium difficile based on their S(Surface)-layers. Anal Chem 2014; 86:10855-63. [PMID: 25343746 PMCID: PMC4222627 DOI: 10.1021/ac5029837] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2014] [Accepted: 10/09/2014] [Indexed: 12/16/2022]
Abstract
Clostridium difficile (C. difficile) infection (CDI) rates have exhibited a steady rise worldwide over the last two decades and the infection poses a global threat due to the emergence of antibiotic resistant strains. Interstrain antagonistic interactions across the host microbiome form an important strategy for controlling the emergence of CDI. The current diagnosis method for CDI, based on immunoassays for toxins produced by pathogenic C. difficile strains, is limited by false negatives due to rapid toxin degradation. Furthermore, simultaneous monitoring of nontoxigenic C. difficile strains is not possible, due to absence of these toxins, thereby limiting its application toward the control of CDI through optimizing antagonistic interstrain interactions. Herein, we demonstrate that morphological differences within the cell wall of particular C. difficile strains with differing S-layer proteins can induce systematic variations in their electrophysiology, due alterations in cell wall capacitance. As a result, dielectrophoretic frequency analysis can enable the independent fingerprinting and label-free separation of intact microbials of each strain type from mixed C. difficile samples. The sensitivity of this contact-less electrophysiological method is benchmarked against the immunoassay and microbial growth rate methods for detecting alterations within both, toxigenic and nontoxigenic C. difficile strains after vancomycin treatment. This microfluidic diagnostic platform can assist in the development of therapies for arresting clostridial infections by enabling the isolation of individual strains, optimization of antibiotic treatments and the monitoring of microbiomes.
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Affiliation(s)
- Yi-Hsuan Su
- Electrical
and Computer Engineering, University of
Virginia at Thornton Hall, 351 McCormick Road, P.O. Box 400743, Charlottesville, Virginia 22904, United States
| | - Cirle A. Warren
- Infectious
Diseases, School of Medicine, University
of Virginia at Infectious Diseases & International Health, P.O. Box 801379, Charlottesville, Virginia 22908, United
States
| | - Richard
L. Guerrant
- Infectious
Diseases, School of Medicine, University
of Virginia at Infectious Diseases & International Health, P.O. Box 801379, Charlottesville, Virginia 22908, United
States
| | - Nathan S. Swami
- Electrical
and Computer Engineering, University of
Virginia at Thornton Hall, 351 McCormick Road, P.O. Box 400743, Charlottesville, Virginia 22904, United States
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Aldape MJ, Heeney DD, Bryant AE, Stevens DL. Tigecycline suppresses toxin A and B production and sporulation in Clostridium difficile. J Antimicrob Chemother 2014; 70:153-9. [PMID: 25151204 DOI: 10.1093/jac/dku325] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Clostridium difficile infection (CDI) is mediated by potent extracellular toxins and is spread largely via bacterial spores. We and others have shown that some antibiotics stimulate C. difficile toxin production in a strain-specific manner; however, the effects of newer anti-C. difficile antibiotics on this process remain to be investigated. METHODS The effects of the protein synthesis inhibitor tigecycline on sporulation and toxin A and toxin B production were compared in historical (strain 9689) and hypervirulent BI/NAP1/027 (strain 5325) isolates of C. difficile in vitro. RESULTS Tigecycline at 1/4× MIC stimulated an increased and earlier toxin A and/or B gene expression in both the historical and the hypervirulent strains, although a commensurate increase in toxin protein production was observed only in the 9689 strain. In fact, in the hypervirulent 5325 strain, toxin production was dramatically suppressed. By comparison, subinhibitory concentrations of vancomycin and metronidazole also stimulated increased protein toxin production by the historical, but not the hypervirulent, strain. In addition, tigecycline dose-dependently reduced viable spore production by both the 9689 and 5325 strains. Vancomycin treatment also suppressed spore formation in both C. difficile strains; however, metronidazole, while reducing spore formation in the 9689 strain, stimulated a near 2 log increase in spore production by the 5325 isolate. CONCLUSIONS In summary, these findings suggest that the treatment of CDI patients with tigecycline could effectively both control disease progression and limit its spread by disrupting sporulation.
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Affiliation(s)
- Michael John Aldape
- Department of Veterans Affairs Medical Center, 500 W. Fort Street, Boise, ID 83702, USA
| | - Dustin Delaney Heeney
- Department of Veterans Affairs Medical Center, 500 W. Fort Street, Boise, ID 83702, USA
| | - Amy Evelyn Bryant
- Department of Veterans Affairs Medical Center, 500 W. Fort Street, Boise, ID 83702, USA University of Washington School of Medicine, 1959 NE Pacific Street, Seattle, WA 98195, USA
| | - Dennis Leroy Stevens
- Department of Veterans Affairs Medical Center, 500 W. Fort Street, Boise, ID 83702, USA University of Washington School of Medicine, 1959 NE Pacific Street, Seattle, WA 98195, USA
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29
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Leuzzi R, Adamo R, Scarselli M. Vaccines against Clostridium difficile. Hum Vaccin Immunother 2014; 10:1466-77. [PMID: 24637887 DOI: 10.4161/hv.28428] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile infection (CDI) is recognized as a major cause of nosocomial diseases ranging from antibiotic related diarrhea to fulminant colitis. Emergence during the last 2 decades of C. difficile strains associated with high incidence, severity and lethal outcomes has increased the challenges for CDI treatment. A limited number of drugs have proven to be effective against CDI and concerns about antibiotic resistance as well as recurring disease solicited the search for novel therapeutic strategies. Active vaccination provides the attractive opportunity to prevent CDI, and intense research in recent years led to development of experimental vaccines, 3 of which are currently under clinical evaluation. This review summarizes recent achievements and remaining challenges in the field of C. difficile vaccines, and discusses future perspectives in view of newly-identified candidate antigens.
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Garneau JR, Valiquette L, Fortier LC. Prevention of Clostridium difficile spore formation by sub-inhibitory concentrations of tigecycline and piperacillin/tazobactam. BMC Infect Dis 2014; 14:29. [PMID: 24422950 PMCID: PMC3897887 DOI: 10.1186/1471-2334-14-29] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 01/08/2014] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Sporulation of Clostridium difficile during infection and persistence of spores within the gut could partly explain treatment failures and recurrence. However, the influence of antibiotics on sporulation is unclear. The objective of our study was to evaluate the impact of ciprofloxacin, metronidazole, piperacillin/tazobactam, tigecycline, and vancomycin on C. difficile sporulation in vitro. METHODS The reference strains ATCC 9689, 630, VPI 10463, and seven other clinical isolates of C. difficile were used, including three epidemic NAP1/027 isolates. Minimum inhibitory concentrations (MIC) were determined and sporulation was assessed after growth in the absence or presence of ≤0.5x MIC concentrations of each antibiotic. RESULTS All strains were sensitive to the antibiotics tested, except ribotype 027 isolates that were resistant to ciprofloxacin (MIC = 128 mg/L). Metronidazole and vancomycin generally did not significantly affect spore production in C. difficile, although vancomycin slightly affected sporulation of a few isolates. Ciprofloxacin inhibited sporulation of ribotype 027 isolates mainly. Interestingly, sub-MIC concentrations of piperacillin/tazobactam reduced spore formation in several isolates. However, the most striking observation was made with tigecycline, with an important reduction of spore formation in most isolates. CONCLUSIONS The capacity of C. difficile to sporulate can be significantly affected by certain antibiotics. The reduced sporulation observed with tigecycline and piperacillin/tazobactam might explain why these antibiotics are generally associated with lower risk of C. difficile infections. In addition, the inhibition of sporulation might partly explain the apparent efficacy of tigecycline for treatment of patients with recurrent infection.
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Affiliation(s)
| | | | - Louis-Charles Fortier
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, 3201 rue Jean Mignault, Sherbrooke, Québec J1E 4K8, Canada.
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In vitro and in vivo antibacterial evaluation of cadazolid, a new antibiotic for treatment of Clostridium difficile infections. Antimicrob Agents Chemother 2013; 58:892-900. [PMID: 24277020 DOI: 10.1128/aac.01830-13] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile is a leading cause of health care-associated diarrhea with significant morbidity and mortality, and new options for the treatment of C. difficile-associated diarrhea (CDAD) are needed. Cadazolid is a new oxazolidinone-type antibiotic that is currently in clinical development for treatment of CDAD. Here, we report the in vitro and in vivo antibacterial evaluation of cadazolid against C. difficile. Cadazolid showed potent in vitro activity against C. difficile with a MIC range of 0.125 to 0.5 μg/ml, including strains resistant to linezolid and fluoroquinolones. In time-kill kinetics experiments, cadazolid showed a bactericidal effect against C. difficile isolates, with >99.9% killing in 24 h, and was more bactericidal than vancomycin. In contrast to metronidazole and vancomycin, cadazolid strongly inhibited de novo toxin A and B formation in stationary-phase cultures of toxigenic C. difficile. Cadazolid also inhibited C. difficile spore formation substantially at growth-inhibitory concentrations. In the hamster and mouse models for CDAD, cadazolid was active, conferring full protection from diarrhea and death with a potency similar to that of vancomycin. These findings support further investigations of cadazolid for the treatment of CDAD.
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32
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Proteomic changes in Bacteroides fragilis exposed to subinhibitory concentration of piperacillin/tazobactam. Anaerobe 2013; 22:69-76. [DOI: 10.1016/j.anaerobe.2013.04.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 04/12/2013] [Indexed: 11/15/2022]
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33
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Bassetti M, Villa G, Pecori D, Arzese A, Wilcox M. Epidemiology, diagnosis and treatment of Clostridium difficile infection. Expert Rev Anti Infect Ther 2013; 10:1405-23. [PMID: 23253319 DOI: 10.1586/eri.12.135] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Clostridium difficile infection (CDI) is considered to be the main cause of bacterial infectious diarrhea in nosocomial settings. Since the beginning of the new century a continuous rise in the incidence of severe CDI has been observed worldwide. Even though some CDI cases are not associated with previous antibiotic exposure, this remains as the principal risk factor for the development of CDI. The rate of recurrences represents perhaps one the most challenging aspect on the management of CDI. There are several microbiological tests available, but glutamate dehydrogenase antigen test can be selected as the first screening step in a diagnostic algorithm, with positive samples then confirmed using a toxin(s) test, to distinguish toxinogenic from nontoxinogenic CDI. Although metronidazole and vancomycin are and have been the mainstay treatment options for CDI, there are some unmet medical and therapeutical needs. Usually oral metronidazole is recommended for initial treatment of nonsevere CDI and vancomycin for treatment of severe disease. Fidaxomicin may be considered in patients who cannot tolerate vancomycin, although more data are needed. For treatment of a nonsevere initial recurrence of CDI, oral metronidazole should be used, but for treatment of subsequent recurrences or more severe cases fidaxomicin may be helpful.
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Affiliation(s)
- Matteo Bassetti
- Infectious Diseases Division, Santa Maria Misericordia University Hospital, Udine, Italy.
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34
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Sengupta S, Chattopadhyay MK, Grossart HP. The multifaceted roles of antibiotics and antibiotic resistance in nature. Front Microbiol 2013; 4:47. [PMID: 23487476 PMCID: PMC3594987 DOI: 10.3389/fmicb.2013.00047] [Citation(s) in RCA: 278] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 02/20/2013] [Indexed: 12/14/2022] Open
Abstract
Antibiotics are chemotherapeutic agents, which have been a very powerful tool in the clinical management of bacterial diseases since the 1940s. However, benefits offered by these magic bullets have been substantially lost in subsequent days following the widespread emergence and dissemination of antibiotic-resistant strains. While it is obvious that excessive and imprudent use of antibiotics significantly contributes to the emergence of resistant strains, antibiotic resistance is also observed in natural bacteria of remote places unlikely to be impacted by human intervention. Both antibiotic biosynthetic genes and resistance-conferring genes have been known to evolve billions of years ago, long before clinical use of antibiotics. Hence it appears that antibiotics and antibiotics resistance determinants have some other roles in nature, which often elude our attention because of overemphasis on the therapeutic importance of antibiotics and the crisis imposed by the antibiotic resistance in pathogens. In the natural milieu, antibiotics are often found to be present in sub-inhibitory concentrations acting as signaling molecules supporting the process of quorum sensing and biofilm formation. They also play an important role in the production of virulence factors and influence host-parasite interactions (e.g., phagocytosis, adherence to the target cell, and so on). The evolutionary and ecological aspects of antibiotics and antibiotic resistance in the naturally occurring microbial community are little understood. Therefore, the actual role of antibiotics in nature warrants in-depth investigations. Studies on such an intriguing behavior of the microorganisms promise insight into the intricacies of the microbial physiology and are likely to provide some lead in controlling the emergence and subsequent dissemination of antibiotic resistance. This article highlights some of the recent findings on the role of antibiotics and the genes that confer resistance to antibiotics in nature.
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35
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Aldape MJ, Packham AE, Nute DW, Bryant AE, Stevens DL. Effects of ciprofloxacin on the expression and production of exotoxins by Clostridium difficile. J Med Microbiol 2013; 62:741-747. [PMID: 23429695 DOI: 10.1099/jmm.0.056218-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Hypervirulent BI/NAP1/027 strains of Clostridium difficile have been associated with increased mortality of C. difficile infection (CDI). The emergence of highly fluoroquinolone (FLQ)-resistant BI/NAP1/027 strains suggests that FLQ exposure may be a risk factor for CDI development. However, the mechanism for this is not clear. We compared the effects of subinhibitory concentrations of ciprofloxacin on Toxin A and B gene expression and protein production in recent (strain 039) and historical (strain 5325) BI/NAP1/027 clinical isolates with high- and low-level ciprofloxacin resistance, respectively. In the highly ciprofloxacin-resistant isolate (strain 039), ciprofloxacin significantly and dose-dependently increased Toxin A gene expression and shifted its expression to earlier in its growth cycle; TcdB gene expression also increased but was less sensitive to low-dose ciprofloxacin. Maximal Toxin A/B production (4 ng ml(-1)) was increased twofold and occurred significantly earlier than in the untreated control. In strain 5325, ciprofloxacin at 0.25×MIC markedly increased both tcdA and tcdB expression but their temporal dynamics were unchanged. Maximal toxin production (250 ng ml(-1)) was reduced approximately threefold compared with that of the untreated control. These results demonstrate significant differences in ciprofloxacin-induced toxin gene expression and protein production among BI/NAP1/027 isolates, and offer a new paradigm for FLQ-associated CDI caused by recent, highly antibiotic-resistant strains.
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Affiliation(s)
| | | | | | - Amy Evelyn Bryant
- University of Washington School of Medicine, Seattle, WA, USA.,Department of Veterans Affairs Medical Center, Boise, ID, USA
| | - Dennis Leroy Stevens
- University of Washington School of Medicine, Seattle, WA, USA.,Department of Veterans Affairs Medical Center, Boise, ID, USA
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36
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Babakhani F, Bouillaut L, Sears P, Sims C, Gomez A, Sonenshein AL. Fidaxomicin inhibits toxin production in Clostridium difficile. J Antimicrob Chemother 2012. [PMID: 23208832 DOI: 10.1093/jac/dks450] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVES Fidaxomicin, which was recently approved for the treatment of Clostridium difficile-associated diarrhoea, demonstrates narrow-spectrum bactericidal activity via inhibition of RNA polymerase. In this study we evaluated its inhibitory activity versus C. difficile toxin gene expression and toxin production by quantifying toxin mRNA and protein. METHODS The effects of fidaxomicin, its major metabolite (OP-1118), vancomycin and metronidazole on toxin A and toxin B production were determined by assaying culture supernatants of two C. difficile isolates (ATCC 43255, a high-level toxin-producing strain, and UK-14, a NAP1/027/BI epidemic strain) using a commercial ELISA. The effects of the drugs on toxin gene expression were assessed in stationary-phase cells of C. difficile strain UK-1 (NAP1/027/BI type epidemic strain) and in the closely related non-epidemic strain CD196 by quantitative RT-PCR. RESULTS Subinhibitory levels (1/4× MIC) of fidaxomicin or OP-1118 (but not vancomycin or metronidazole) strongly suppressed toxin production in C. difficile (≥ 60%) through at least 1 week of culture. Additionally, transcripts from the pathogenicity loci (tcdR, tcdA and tcdB) were nearly completely inhibited by both fidaxomicin (2× MIC) and OP-1118 (2.5× MIC), but not vancomycin (2.5× MIC). CONCLUSIONS Both fidaxomicin and OP-1118 are able to inhibit toxin production in vitro, which may explain prior post-treatment observations of less frequent detectable toxin in fidaxomicin-treated patients (27 subjects) than those treated with vancomycin (8 patients).
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Affiliation(s)
- Farah Babakhani
- Optimer Pharmaceuticals, Inc., 4755 Nexus Center Drive, San Diego, CA 92121, USA.
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37
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Cernat RC, Scott KP. Evaluation of novel assays to assess the influence of different iron sources on the growth of Clostridium difficile. Anaerobe 2012; 18:298-304. [PMID: 22554901 DOI: 10.1016/j.anaerobe.2012.04.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 03/14/2012] [Accepted: 04/16/2012] [Indexed: 01/05/2023]
Abstract
The ability of four Clostridium difficile strains to utilize various exogenous organic and inorganic iron sources for growth under iron-depleted (250 μM DPP) and iron-limited (75 μM DPP) conditions was analyzed in liquid broth cultures grown in tubes and in microtiter plates, and data compared with results from a bioassay developed on solid media. The growth profile of C. difficile varied depending on the iron source and availability. Addition of FeSO(4), FeCl(3), Fe citrate and ferritin allowed growth in an iron-depleted environment whereas glycoproteins (iron-saturated and low-iron lactoferrin, apo- and holo-transferrin) and heme proteins (hemoglobin, hematin and hemin) did not. All iron sources, except lactoferrin, were able to restore bacterial growth under iron-limited conditions to varying extents. The results demonstrated that the broth microtiter assay developed here was reproducible, reliable and convenient for high-throughput analysis of the growth of C. difficile compared to alternative traditional methods.
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Affiliation(s)
- Ramona C Cernat
- Microbial Ecology, Gut Health Division, Rowett Institute of Nutrition and Health, University of Aberdeen, Bucksburn, UK
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38
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Chen HY, Chen CC, Fang CS, Hsieh YT, Lin MH, Shu JC. Vancomycin activates σ(B) in vancomycin-resistant Staphylococcus aureus resulting in the enhancement of cytotoxicity. PLoS One 2011; 6:e24472. [PMID: 21912698 PMCID: PMC3166330 DOI: 10.1371/journal.pone.0024472] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 08/11/2011] [Indexed: 12/16/2022] Open
Abstract
The alternative transcription factor σB is responsible for transcription in Staphylococcus aureus during the stress response. Many virulence-associated genes are directly or indirectly regulated by σB. We hypothesized that treatment with antibiotics may act as an environmental stressor that induces σB activity in antibiotic-resistant strains. Several antibiotics with distinct modes of action, including ampicillin (12 µg/ml), vancomycin (16 or 32 µg/ml), chloramphenicol (15 µg/ml), ciprofloxacin (0.25 µg/ml), and sulfamethoxazole/trimethoprim (SXT, 0.8 µg/ml), were investigated for their ability to activate this transcription factor. We were especially interested in the stress response in vancomycin-resistant S. aureus (VRSA) strains treated with vancomycin. The transcription levels of selected genes associated with virulence were also measured. Real-time quantitative reverse transcription PCR was employed to evaluate gene transcription levels. Contact hemolytic and cytotoxicity assays were used to evaluate cell damage following antibiotic treatment. Antibiotics that target the cell wall (vancomycin and ampicillin) and SXT induced σB activity in VRSA strains. Expression of σB-regulated virulence genes, including hla and fnbA, was associated with the vancomycin-induced σB activity in VRSA strains and the increase in cytotoxicity upon vancomycin treatment. These effects were not observed in the sigB-deficient strain but were observed in the complemented strain. We demonstrate that sub-minimum inhibitory concentration (sub-MIC) levels of antibiotics act as environmental stressors and activate the stress response sigma factor, σB. The improper use of antibiotics may alter the expression of virulence factors through the activation of σB in drug-resistant strains of S. aureus and lead to worse clinical outcomes.
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Affiliation(s)
- Hong-Yi Chen
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Chien-Cheng Chen
- Department of Biotechnology, National Kaohsiung Normal University, Kaohsiung, Taiwan
| | - Chun-Sheng Fang
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Yi-Ting Hsieh
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
| | - Mei-Hui Lin
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
| | - Jwu-Ching Shu
- Department of Medical Biotechnology and Laboratory Science, Chang Gung University, Taoyuan, Taiwan
- Research Center for Pathogenic Bacteria, Chang Gung University, Taoyuan, Taiwan
- * E-mail:
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39
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Baines SD, Noel AR, Huscroft GS, Todhunter SL, O'Connor R, Hobbs JK, Freeman J, Lovering AM, Wilcox MH. Evaluation of linezolid for the treatment of Clostridium difficile infection caused by epidemic strains using an in vitro human gut model. J Antimicrob Chemother 2011; 66:1537-46. [PMID: 21504940 DOI: 10.1093/jac/dkr155] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
OBJECTIVES Therapeutic options in Clostridium difficile infection (CDI) are limited. We examined linezolid activity in vitro and potential therapeutic efficacy using a gut model of CDI. METHODS MICs were determined by agar incorporation for 118 diverse C. difficile faecal isolates, including epidemic strains and strains with reduced susceptibility to metronidazole. CDI was established in two gut model experiments using C. difficile epidemic strains (ribotypes 027 and 106) and linezolid was dosed to achieve human gut concentrations. RESULTS Linezolid demonstrated good in vitro activity against 98% of the isolates. Two isolates (PCR ribotypes 023 and 067) demonstrated resistance to linezolid, although supplementary susceptibility testing of ribotype 023 isolates did not detect further resistance. In a gut model that simulates CDI, linezolid reduced the duration of cytotoxin production by C. difficile PCR ribotype 027 without influencing viable counts of vegetative forms of the organism. C. difficile PCR ribotype 106 viable counts declined at a faster rate than those of PCR ribotype 027 following dosing with linezolid, but cytotoxin titres declined at a similar rate to an untreated control. Gut flora perturbation occurring on linezolid exposure reversed after drug cessation. Recrudescence of spore germination with subsequent cytotoxin was seen with the C. difficile ribotype 106 strain. Resistance to linezolid was not detected either during linezolid instillation or post-dosing. CONCLUSIONS Linezolid may reduce toxin levels, as reported in staphylococci and streptococci. Further evaluation is warranted of the effect of linezolid on expression of C. difficile toxin, and to investigate potential recurrence of CDI following cessation of linezolid.
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Affiliation(s)
- Simon D Baines
- Microbiology, University of Leeds and Leeds Teaching Hospitals, Leeds General Infirmary, Old Medical School, Leeds LS1 3EX, UK
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40
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Metcalf DS, Weese JS. Binary toxin locus analysis in Clostridium difficile. J Med Microbiol 2011; 60:1137-1145. [PMID: 21459907 DOI: 10.1099/jmm.0.028498-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The objective of this study was to compare full binary toxin loci (CDTloc) sequences from a collection of Clostridium difficile isolates in an effort to further understand the regulation of the binary toxin (CdtAB) and its putative regulator (CdtR). Sequences from different ribotypes and toxinotypes were analysed phylogenetically and for polymorphisms, non-sense mutations, promoter features and signal sequences. Expression of cdtA, which was also representative of cdtB expression, was measured by quantitative PCR (qPCR). Several consensus promoter features and various polymorphisms were identified including a non-sense mutation identified in a ribotype 078 cdtR gene that is predicted to result in a severely truncated protein. Despite this mutation, cdtA expression was still detected by qPCR. Dendrograms based on total sequences indicated that isolates belonging to the same ribotype shared the greatest similarity within the binary toxin locus. Although cdtR is thought to be involved in regulation of cdtA expression, a cdtR non-sense mutation did not inhibit expression of cdtA, suggesting that either the truncated protein is functional or another regulator of the binary toxin exists.
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Affiliation(s)
- Devon S Metcalf
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
| | - J Scott Weese
- Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON N1G 2W1, Canada
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41
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Mathur T, Kumar M, Barman TK, Kumar GR, Kalia V, Singhal S, Raj VS, Upadhyay DJ, Das B, Bhatnagar PK. Activity of RBx 11760, a novel biaryl oxazolidinone, against Clostridium difficile. J Antimicrob Chemother 2011; 66:1087-95. [PMID: 21393140 DOI: 10.1093/jac/dkr033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
OBJECTIVES RBx 11760, a novel oxazolidinone, was investigated for in vitro and in vivo activity against Clostridium difficile. METHODS The in vitro activity of RBx 11760 and three other agents against 50 diverse C. difficile clinical isolates and other obligate anaerobic bacteria was determined. The effect of RBx 11760 on sporulation and toxin production was determined against different C. difficile isolates. We used a hamster infection model to investigate the efficacy of RBx 11760, vancomycin and metronidazole. The mechanism of action of RBx 11760 against C. difficile ATCC 43255 was determined by macromolecular synthesis inhibition. RESULTS RBx 11760 MICs were in the range of 0.5-1 mg/L for C. difficile isolates, and it demonstrated concentration-dependent killing of C. difficile ATCC 43255 and C. difficile 6387 up to 2-4× MIC (1-2 mg/L). RBx 11760, at concentrations as low as 0.25-0.5 mg/L, resulted in a significant reduction in de novo toxin production as well as sporulation in different C. difficile isolates. In contrast, vancomycin, metronidazole and linezolid had little or no effect on toxin production and appeared to promote the formation of spores. In the hamster infection model, treatment with RBx 11760 resulted in prolonged survival of animals as compared with vancomycin or metronidazole, which correlated well with the histopathology results. Macromolecular labelling results suggest that RBx 11760 is a potent inhibitor of bacterial protein synthesis. CONCLUSIONS RBx 11760 showed excellent in vitro and in vivo activity against C. difficile, and it could be a promising novel candidate for future drug development against C. difficile infection.
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Affiliation(s)
- Tarun Mathur
- Department of Infectious Diseases, New Drug Discovery Research, Ranbaxy Research Laboratories, Gurgaon, Haryana, India.
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Evaluation of candidate reference genes in Clostridium difficile for gene expression normalization. Anaerobe 2010; 16:439-43. [DOI: 10.1016/j.anaerobe.2010.06.007] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Revised: 06/16/2010] [Accepted: 06/20/2010] [Indexed: 02/04/2023]
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Effects of subinhibitory concentrations of antibiotics on colonization factor expression by moxifloxacin-susceptible and moxifloxacin-resistant Clostridium difficile strains. Antimicrob Agents Chemother 2009; 53:5155-62. [PMID: 19805572 DOI: 10.1128/aac.00532-09] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Recent outbreaks of Clostridium difficile infection have been related to the emergence of the NAP1/027 epidemic strain. This strain demonstrates increased virulence and resistance to the C-8-methoxyfluoroquinolones gatifloxacin and moxifloxacin. These antibiotics have been implicated as major C. difficile infection-inducing agents. We investigated by real-time reverse transcription-PCR the impact of subinhibitory concentrations of ampicillin, clindamycin, ofloxacin, and moxifloxacin on the expression of genes encoding three colonization factors, the protease Cwp84, the high-molecular-weight S-layer protein, and the fibronectin-binding protein Fbp68. We have previously shown in six non-NAP1/027 moxifloxacin-susceptible strains that the presence of ampicillin or clindamycin induced an upregulation of these genes, whereas the presence of fluoroquinolones did not. The objective of this study was to analyze the expression of these genes under the same conditions in four NAP1/027 strains, one moxifloxacin susceptible and three moxifloxacin resistant. Two in vitro-selected moxifloxacin-resistant mutants were also analyzed. Moxifloxacin resistance was associated with the Thr82-->Ile substitution in GyrA in all but one of the moxifloxacin-resistant strains. The expression of cwp84 and slpA was strongly increased after culture with ampicillin or clindamycin in NAP1/027 strains. Interestingly, after culture with fluoroquinolones, the expression of cwp84 and slpA was only increased in four moxifloxacin-resistant strains, including the NAP1/027 strains and one of the in vitro-selected mutants. The overexpression of cwp84 was correlated with increased production of the protease Cwp84. The historical NAP1/027 moxifloxacin-susceptible strain and its mutant appear to be differently regulated by fluoroquinolones. Overall, fluoroquinolones appear to favor the expression of some colonization factor-encoding genes in resistant C. difficile strains. The fluoroquinolone resistance of the NAP1/027 epidemic strains could be considered an ecological advantage. This could also increase their colonization fitness and promote the infection.
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Denève C, Janoir C, Poilane I, Fantinato C, Collignon A. New trends in Clostridium difficile virulence and pathogenesis. Int J Antimicrob Agents 2009; 33 Suppl 1:S24-8. [PMID: 19303565 DOI: 10.1016/s0924-8579(09)70012-3] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The disease spectrum caused by Clostridium difficile infection ranges from antibiotic-associated diarrhoea to life-threatening clinical manifestations such as pseudomembranous colitis. C. difficile infection is precipitated by antimicrobial therapy that causes a disruption of the normal colonic microbiota, predisposing to C. difficile intestinal colonisation. The pathogenicity of C. difficile is mediated by two exotoxins, TcdA and TcdB, both of which damage the human colonic mucosa and are potent cytotoxic enzymes. C. difficile must first be implanted in the gut and attach to epithelial cells, which are protected by a layer of dense mucus. Confirmed and putative accessory virulence factors that could play a role in adherence and intestinal colonisation have been identified and include proteolytic enzymes and adhesins. Recently, the epidemiology of C. difficile infection has radically changed and an increased incidence is associated with outbreaks in North America and Europe. Several reports suggest that disease severity is increasing to include sepsis syndrome and toxin megacolon. Elderly, debilitated patients in hospitals and nursing homes are particularly vulnerable. A hypervirulent, epidemic strain has been associated with the changing epidemiology and severity of disease. Here, we review the characteristics of the epidemic NAP1, PCR ribotype 027 C. difficile strain that could explain its hypervirulence and epidemic spread.
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Affiliation(s)
- C Denève
- EA 4043, Université Paris-Sud, Châtenay-Malabry, France
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45
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Cummins J, Reen FJ, Baysse C, Mooij MJ, O'Gara F. Subinhibitory concentrations of the cationic antimicrobial peptide colistin induce the pseudomonas quinolone signal in Pseudomonas aeruginosa. MICROBIOLOGY-SGM 2009; 155:2826-2837. [PMID: 19477905 DOI: 10.1099/mic.0.025643-0] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Colistin is an important cationic antimicrobial peptide (CAMP) in the fight against Pseudomonas aeruginosa infection in cystic fibrosis (CF) lungs. The effects of subinhibitory concentrations of colistin on gene expression in P. aeruginosa were investigated by transcriptome and functional genomic approaches. Analysis revealed altered expression of 30 genes representing a variety of pathways associated with virulence and bacterial colonization in chronic infection. These included response to osmotic stress, motility, and biofilm formation, as well as genes associated with LPS modification and quorum sensing (QS). Most striking was the upregulation of Pseudomonas quinolone signal (PQS) biosynthesis genes, including pqsH, pqsB and pqsE, and the phenazine biosynthesis operon. Induction of this central component of the QS network following exposure to subinhibitory concentrations of colistin may represent a switch to a more robust population, with increased fitness in the competitive environment of the CF lung.
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Affiliation(s)
- Joanne Cummins
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - F Jerry Reen
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - Christine Baysse
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - Marlies J Mooij
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
| | - Fergal O'Gara
- BIOMERIT Research Centre, Department of Microbiology, University College Cork, Ireland
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Leffler DA, Lamont JT. Treatment of Clostridium difficile-associated disease. Gastroenterology 2009; 136:1899-912. [PMID: 19457418 DOI: 10.1053/j.gastro.2008.12.070] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 12/12/2008] [Accepted: 12/22/2008] [Indexed: 02/07/2023]
Abstract
Clostridium difficile infection is an increasing burden to the health care system, totaling more than $1 billion/year in the United States. Treatment of patients with C difficile infection with metronidazole or vancomycin reduces morbidity and mortality, although the number of patients that do not respond to metronidazole is increasing. Despite initial response rates of greater than 90%, 15%-30% of patients have a relapse in symptoms after successful initial therapy, usually in the first few weeks after treatment is discontinued. Failure to develop specific antibody response has recently been identified as a critical factor in recurrence. The review discusses the different management strategies for initial and recurrent symptomatic C difficile infections.
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Affiliation(s)
- Daniel A Leffler
- Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA.
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47
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Ochsner UA, Bell SJ, O'Leary AL, Hoang T, Stone KC, Young CL, Critchley IA, Janjic N. Inhibitory effect of REP3123 on toxin and spore formation in Clostridium difficile, and in vivo efficacy in a hamster gastrointestinal infection model. J Antimicrob Chemother 2009; 63:964-71. [PMID: 19251726 DOI: 10.1093/jac/dkp042] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
OBJECTIVES REP3123 is a fully synthetic methionyl-tRNA synthetase inhibitor in pre-clinical development as a novel agent to treat Clostridium difficile infection (CDI). This novel agent was investigated for its ability to block the production of toxins and spores, and was tested for efficacy in vivo in a hamster model. METHODS Clostridial toxin levels were determined qualitatively using monoclonal antibodies and by cytotoxicity assays. Spores were detected by staining and by quantitative dilution plating after ethanol treatment. Efficacy of REP3123 was tested in a clindamycin-induced C. difficile hamster gastrointestinal (GI) infection model. RESULTS REP3123 at concentrations as low as 1 mg/L inhibited de novo toxin production in high cell density, stationary phase cultures of C. difficile. Among comparator agents currently used for CDI therapy, vancomycin required much higher levels of 20 mg/L, and metronidazole had no effect on toxin levels. REP3123 caused a >10-fold reduction of the sporulation rate in vitro. Vancomycin and, in particular, metronidazole appeared to promote the formation of spores. REP3123, at concentrations as low as 0.5 mg/kg, demonstrated efficacy in the hamster model of CDI and was superior to vancomycin in the overall survival of the animals at the end of the study (33 days). CONCLUSIONS REP3123 inhibited growth of C. difficile, affected the production of toxins and spores and demonstrated superior efficacy compared with vancomycin in the hamster GI infection model. This agent may be a promising candidate for CDI treatment; in particular, the inhibition of toxin production and spore formation may reduce the severity and spread of the disease, respectively.
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Martinez JL, Fajardo A, Garmendia L, Hernandez A, Linares JF, Martínez-Solano L, Sánchez MB. A global view of antibiotic resistance. FEMS Microbiol Rev 2009; 33:44-65. [DOI: 10.1111/j.1574-6976.2008.00142.x] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
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Abstract
The large majority of antibiotics currently used for treating infections and the antibiotic resistance genes acquired by human pathogens each have an environmental origin. Recent work indicates that the function of these elements in their environmental reservoirs may be very distinct from the "weapon-shield" role they play in clinical settings. Changes in natural ecosystems, including the release of large amounts of antimicrobials, might alter the population dynamics of microorganisms, including selection of resistance, with consequences for human health that are difficult to predict.
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Affiliation(s)
- José L Martínez
- Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología (CSIC), Darwin 3, Campus UAM, Cantoblanco, 28049-Madrid, and CIBERESP, Spain.
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50
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Affiliation(s)
- Ian R. Poxton
- Centre for Infectious Diseases, University of Edinburgh College of Medicine and Veterinary Medicine, The Chancellor's Building, 49 Little France Crescent, Edinburgh EH16 4SB, UK
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