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Markantonis JE, Fallon JT, Madan R, Alam MZ. Clostridioides difficile Infection: Diagnosis and Treatment Challenges. Pathogens 2024; 13:118. [PMID: 38392856 PMCID: PMC10891949 DOI: 10.3390/pathogens13020118] [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: 01/05/2024] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/25/2024] Open
Abstract
Clostridioides difficile is the most important cause of healthcare-associated diarrhea in the United States. The high incidence and recurrence rates of C. difficile infection (CDI), associated with high morbidity and mortality, pose a public health challenge. Although antibiotics targeting C. difficile bacteria are the first treatment choice, antibiotics also disrupt the indigenous gut flora and, therefore, create an environment that is favorable for recurrent CDI. The challenge of treating CDI is further exacerbated by the rise of antibiotic-resistant strains of C. difficile, placing it among the top five most urgent antibiotic resistance threats in the USA. The evolution of antibiotic resistance in C. difficile involves the acquisition of new resistance mechanisms, which can be shared among various bacterial species and different C. difficile strains within clinical and community settings. This review provides a summary of commonly used diagnostic tests and antibiotic treatment strategies for CDI. In addition, it discusses antibiotic treatment and its resistance mechanisms. This review aims to enhance our current understanding and pinpoint knowledge gaps in antimicrobial resistance mechanisms in C. difficile, with an emphasis on CDI therapies.
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Affiliation(s)
- John E. Markantonis
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA; (J.E.M.); (J.T.F.)
| | - John T. Fallon
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA; (J.E.M.); (J.T.F.)
| | - Rajat Madan
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
- Veterans Affairs Medical Center, Cincinnati, OH 45220, USA
| | - Md Zahidul Alam
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27834, USA; (J.E.M.); (J.T.F.)
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Tanaka Y, Tashiro S, Ikegami S, Enoki Y, Taguchi K, Matsumoto K. Oral teicoplanin administration suppresses recurrence of Clostridioides difficile infection: Proof of concept. Anaerobe 2023; 84:102789. [PMID: 37879532 DOI: 10.1016/j.anaerobe.2023.102789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/17/2023] [Accepted: 10/22/2023] [Indexed: 10/27/2023]
Abstract
OBJECTIVES Teicoplanin is a potential antimicrobial candidate for Clostridioides difficile infection (CDI) treatment. However, the therapeutic potential of teicoplanin against severe CDI has not been clinically proven. In the present study, we investigated the efficacy of oral teicoplanin administration against severe CDI and the recurrence of severe CDI after teicoplanin treatment in a mouse model. METHODS A lethal CDI mouse model was established by colonizing the mice with C. difficile ATCC® 43255; they were orally administered teicoplanin (128 mg/kg/d) or vancomycin (160 mg/kg/d) for 10 d, 24 h after C. difficile spore challenge, and physiological and biological responses were monitored for 20 d after the initial antibiotic treatment. We also performed the in vitro time-kill assay and determined minimum inhibitory concentration (MIC), post-antibiotic effect, and toxin production with antibiotic exposure. RESULTS The therapeutic response (survival rates, body weight change, clinical sickness score grading, C. difficile load, and toxin titer in feces) of oral teicoplanin administration was comparable to that of oral vancomycin administration in the lethal CDI mouse model. Moreover, teicoplanin treatment suppressed the re-onset of diarrhea and re-increase in toxin titer 10 d after treatment compared with that by vancomycin treatment. In in vitro experiments, teicoplanin exhibited time-dependent antibacterial activity and possessed lower MIC and longer post-antibiotic effect than vancomycin against C. difficile. C. difficile toxin production was numerically lower with teicoplanin exposure than with vancomycin exposure. CONCLUSIONS The results obtained from the present basic experiments could suggest that teicoplanin is a potential antibiotic for the treatment of severe CDI with recurrence-prevention activity.
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Affiliation(s)
- Yoko Tanaka
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
| | - Sho Tashiro
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
| | - Shintaro Ikegami
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
| | - Yuki Enoki
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
| | - Kazuaki Taguchi
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
| | - Kazuaki Matsumoto
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, Tokyo, Japan.
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Tashiro S, Taguchi K, Enoki Y, Matsumoto K. Antimicrobial Efficacy Evaluations of Metronidazole against Clostridioides difficile Infection using Fecal Pharmacokinetic and Pharmacodynamic Analyses. Pharm Res 2023; 40:1799-1806. [PMID: 37226025 DOI: 10.1007/s11095-023-03537-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 05/13/2023] [Indexed: 05/26/2023]
Abstract
OBJECTIVES The pharmacokinetics/pharmacodynamics (PK/PD) characteristics of metronidazole (MNZ) in Clostridioides difficile infection (CDI) remain unclear. We aimed to determine the PK/PD characteristics of MNZ using a fecal PK/PD analysis model. METHODS Susceptibility testing, time-kill studies, and post-antibiotic effect (PAE) measurements were performed to evaluate in vitro PD profiles. MNZ was subcutaneously administered to mice infected with C. difficile ATCC® 43255 to evaluate in vivo PK and PD profiles, followed by determining fecal PK/PD indices with target value. RESULTS MNZ exerted concentration-dependent bactericidal activities with minimum inhibitory concentration (MIC) and PAE being 0.79 µg/mL and 4.8 h, respectively, against C. difficile ATCC® 43255. The reduction in vegetative cells in feces and treatment outcomes were most closely correlated with the ratio of the area under the fecal drug concentration-time curve from 0 to 24 h to the MIC (fecal AUC24/MIC). The target value of fecal AUC24/MIC to achieve a 1 log10 reduction in vegetative cells was 188. Upon meeting the target value, high survival rates (94.5%) and low clinical sickness score grading (5.2) were achieved in the CDI mouse models. CONCLUSIONS The PK/PD index and its target value of MNZ for CDI treatment was fecal AUC24/MIC ≥ 188. These findings may contribute to the effective clinical use of MNZ.
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Affiliation(s)
- Sho Tashiro
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo, 105-8512, Japan
| | - Kazuaki Taguchi
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo, 105-8512, Japan.
| | - Yuki Enoki
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo, 105-8512, Japan
| | - Kazuaki Matsumoto
- Division of Pharmacodynamics, Keio University Faculty of Pharmacy, 1-5-30 Shibakoen, Minato-ku, Tokyo, 105-8512, Japan
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Walters HA, Welter BH, Knight EW, Villano MA, Keramati CA, Morris MT, Temesvari LA. Hypothetical proteins play a role in stage conversion, virulence, and the stress response in the Entamoeba species. Exp Parasitol 2022; 243:108410. [DOI: 10.1016/j.exppara.2022.108410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 09/26/2022] [Accepted: 10/18/2022] [Indexed: 11/30/2022]
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Pitcher NP, Harjani JR, Zhao Y, Jin J, Knight DR, Li L, Putsathit P, Riley TV, Carter GP, Baell JB. Development of 1,2,4-Oxadiazole Antimicrobial Agents to Treat Enteric Pathogens within the Gastrointestinal Tract. ACS OMEGA 2022; 7:6737-6759. [PMID: 35252669 PMCID: PMC8892681 DOI: 10.1021/acsomega.1c06294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
Colonization of the gastrointestinal (GI) tract with pathogenic bacteria is an important risk factor for the development of certain potentially severe and life-threatening healthcare-associated infections, yet efforts to develop effective decolonization agents have been largely unsuccessful thus far. Herein, we report modification of the 1,2,4-oxadiazole class of antimicrobial compounds with poorly permeable functional groups in order to target bacterial pathogens within the GI tract. We have identified that the quaternary ammonium functionality of analogue 26a results in complete impermeability in Caco-2 cell monolayers while retaining activity against GI pathogens Clostridioides difficile and multidrug-resistant (MDR) Enterococcus faecium. Low compound recovery levels after oral administration in rats were observed, which suggests that the analogues may be susceptible to degradation or metabolism within the gut, highlighting a key area for optimization in future efforts. This study demonstrates that modified analogues of the 1,2,4-oxadiazole class may be potential leads for further development of colon-targeted antimicrobial agents.
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Affiliation(s)
- Noel P. Pitcher
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jitendra R. Harjani
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Yichao Zhao
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Jianwen Jin
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Daniel R. Knight
- School
of Medical and Health Sciences, Edith Cowan
University, Joondalup, Western Australia 6027, Australia
- School of
Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Queen Elizabeth
II Medical Centre, Nedlands, Western Australia 6009, Australia
- Medical,
Molecular and Forensic Sciences, Murdoch
University, Murdoch, Western Australia 6150, Australia
- Department
of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Lucy Li
- Department
of Microbiology & Immunology, Peter Doherty Institute for Infection
and Immunity, The University of Melbourne, Melbourne, Victoria 3000, Australia
| | - Papanin Putsathit
- School
of Medical and Health Sciences, Edith Cowan
University, Joondalup, Western Australia 6027, Australia
- School of
Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Queen Elizabeth
II Medical Centre, Nedlands, Western Australia 6009, Australia
- Medical,
Molecular and Forensic Sciences, Murdoch
University, Murdoch, Western Australia 6150, Australia
- Department
of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Thomas V. Riley
- School
of Medical and Health Sciences, Edith Cowan
University, Joondalup, Western Australia 6027, Australia
- School of
Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Queen Elizabeth
II Medical Centre, Nedlands, Western Australia 6009, Australia
- Medical,
Molecular and Forensic Sciences, Murdoch
University, Murdoch, Western Australia 6150, Australia
- Department
of Microbiology, PathWest Laboratory Medicine, Queen Elizabeth II Medical Centre, Nedlands, Western Australia 6009, Australia
| | - Glen P. Carter
- Department
of Microbiology & Immunology, Peter Doherty Institute for Infection
and Immunity, The University of Melbourne, Melbourne, Victoria 3000, Australia
| | - Jonathan B. Baell
- School
of Pharmaceutical Sciences, Nanjing Tech
University, No. 30 South
Puzhu Road, Nanjing 211816, People’s Republic of China
- Medicinal
Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
- Australian
Translational Medicinal Chemistry Facility (ATMCF), Monash University, Parkville, Victoria 3052, Australia
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Abuqwider J, Altamimi M, Mauriello G. Limosilactobacillus reuteri in Health and Disease. Microorganisms 2022; 10:microorganisms10030522. [PMID: 35336098 PMCID: PMC8953724 DOI: 10.3390/microorganisms10030522] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 02/01/2023] Open
Abstract
Limosilactobacillus reuteri is a microorganism with valuable probiotic qualities that has been widely employed in humans to promote health. It is a well-studied probiotic bacterium that exerts beneficial health effects due to several metabolic mechanisms that enhance the production of anti-inflammatory cytochines and modulate the gut microbiota by the production of antimicrobial molecules, including reuterin. This review provides an overview of the data that support the role of probiotic properties, and the antimicrobial and immunomodulatory effects of some L. reuteri strains in relation to their metabolite production profile on the amelioration of many diseases and disorders. Although the results discussed in this paper are strain dependent, they show that L. reuteri, by different mechanisms and various metabolites, may control body weight and obesity, improve insulin sensitivity and glucose homeostasis, increase gut integrity and immunomodulation, and attenuate hepatic disorders. Gut microbiota modulation by ingesting probiotic L. reuteri strains could be a promising preventative and therapeutic approach against many diseases and disorders.
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Affiliation(s)
- Jumana Abuqwider
- Department of Agricultural Science, University of Naples Federico II, 80049 Naples, Italy;
| | - Mohammad Altamimi
- Department of Nutrition and Food Technology, Faculty of Agriculture and Veterinary Medicine, An-Najah National University, Nablus P.O. Box 7, Palestine;
| | - Gianluigi Mauriello
- Department of Agricultural Science, University of Naples Federico II, 80049 Naples, Italy;
- Correspondence: ; Tel.: +39-081-2539452
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Jang AY, Rod-In W, Monmai C, Sohn M, Kim TR, Jeon MG, Park WJ. Anti-inflammatory potential of Lactobacillus reuteri LM1071 via eicosanoid regulation in LPS-stimulated RAW264.7 cells. J Appl Microbiol 2021; 133:67-75. [PMID: 34688224 DOI: 10.1111/jam.15331] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 10/13/2021] [Accepted: 10/18/2021] [Indexed: 02/06/2023]
Abstract
AIMS To investigate anti-inflammatory effects of Lactobacillus reuteri LM1071 in lipopolysaccharides (LPS)-induced inflammation RAW264.7 cells. METHODS AND RESULTS To evaluate anti-inflammatory activities of L. reuteri LM1071, LPS-stimulated RAW264.7 cells were used. Gene expression levels of eight immune-associated genes including IL-1β, IL-6 and TNF-α and protein production levels of COX-1 and COX-2 were analysed. Moreover, the production of eicosanoids as important biomarkers for anti-inflammation was determined. CONCLUSIONS The current study demonstrates that L. reuteri LM1071 has anti-inflammatory potential by inhibiting the production of inflammation mediators such as NO, eicosanoids such as PGE1 & PGE2, pro-inflammatory cytokines and COX proteins. It can also enhance the production of inflammatory associated genes such as IL-11, BMP4, LEFTY2 and EET metabolite. SIGNIFICANCE AND IMPACT OF THE STUDY Lactobacillus reuteri is one of the crucial bacteria for food fermentation. It can be found in the gastrointestinal system of human and animals. Several studies have shown that L. reuteri has valuable effects on host health. The current study firstly demonstrated that L. reuteri has a beneficial effect on the inflammation containing the variation of eicosanoids (PGE1 and PGE2) which are one of the most important biomarkers and moreover eicosanoid-associated genes as well as proteins (COX-2).
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Affiliation(s)
- A-Yeong Jang
- Department of Marine Food Science and Technology, Gangneung-Wonju National University, Gangneung, Gangwon, Korea
| | - Weerawan Rod-In
- Department of Marine Food Science and Technology, Gangneung-Wonju National University, Gangneung, Gangwon, Korea
| | - Chaiwat Monmai
- Department of Marine Food Science and Technology, Gangneung-Wonju National University, Gangneung, Gangwon, Korea
| | - Minn Sohn
- Center for Research and Development, LACTOMASON, Jinju, Korea
| | - Tae-Rahk Kim
- Center for Research and Development, LACTOMASON, Jinju, Korea
| | - Min-Gyu Jeon
- Center for Research and Development, LACTOMASON, Jinju, Korea
| | - Woo Jung Park
- Department of Marine Food Science and Technology, Gangneung-Wonju National University, Gangneung, Gangwon, Korea
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The Integrity of Heme Is Essential for Reproducible Detection of Metronidazole-Resistant Clostridioides difficile by Agar Dilution Susceptibility Tests. J Clin Microbiol 2021; 59:e0058521. [PMID: 34132582 DOI: 10.1128/jcm.00585-21] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Metronidazole resistance in clinical Clostridioides difficile is often described as unstable, since resistant strains reportedly appear susceptible following freezer storage or brief passage. This has presented a conundrum for adopting susceptibility testing to accurately evaluate the connection between metronidazole resistance and decreased clinical efficacy of metronidazole in patients with C. difficile infections (CDIs). We discovered that supplementation of microbiological media with the metalloporphyrin heme is crucial for detection of metronidazole-resistant C. difficile using the agar dilution susceptibility testing method. Known metronidazole-resistant strains appeared susceptible to metronidazole in media lacking heme. Similarly, these resistant strains exhibited increased susceptibility to metronidazole when tested on heme-containing agars that were exposed to room light for more than 1 day, likely due to heme photodecomposition. In parallel experiments, resistance was reproducibly detected when heme-containing agars were either prepared and used on the same day or protected from light and then used on subsequent days. Notably, heme did not influence the susceptibilities of drug-susceptible strains that were of the same ribotype as the resistant strains. These findings firmly show that the consistent detection of metronidazole-resistant C. difficile is dependent upon heme and its protection from light. Studies are warranted to determine the extent to which this heme-associated metronidazole-resistant phenotype affects the clinical efficacy of metronidazole in CDI and the underlying genetic and biochemical mechanisms.
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Price E, Kalvass JC, DeGoey D, Hosmane B, Doktor S, Desino K. Global Analysis of Models for Predicting Human Absorption: QSAR, In Vitro, and Preclinical Models. J Med Chem 2021; 64:9389-9403. [PMID: 34152772 DOI: 10.1021/acs.jmedchem.1c00669] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Models intended to predict intestinal absorption are an essential part of the drug development process. Although many models exist for capturing intestinal absorption, many questions still exist around the applicability of these models to drug types like "beyond rule of 5" (bRo5) and low absorption compounds. This presents a challenge as current models have not been rigorously tested to understand intestinal absorption. Here, we assembled a large, structurally diverse dataset of ∼1000 compounds with known in vitro, preclinical, and human permeability and/or absorption data. In silico (quantitative structure-activity relationship), in vitro (Caco-2), and in vivo (rat) models were statistically evaluated for predictive performance against this human intestinal absorption dataset. We expect this evaluation to serve as a resource for DMPK scientists and medicinal/computational chemists to increase their understanding of permeability and absorption model utility and applications for academia and industry.
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Affiliation(s)
- Edward Price
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
| | - J Cory Kalvass
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
| | - David DeGoey
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
| | - Balakrishna Hosmane
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
| | - Stella Doktor
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
| | - Kelly Desino
- Research and Development, AbbVie Inc., 1 North Waukegan Road, North Chicago, Illinois 60064, United States
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Wallace MJ, Fishbein SRS, Dantas G. Antimicrobial resistance in enteric bacteria: current state and next-generation solutions. Gut Microbes 2020; 12:1799654. [PMID: 32772817 PMCID: PMC7524338 DOI: 10.1080/19490976.2020.1799654] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Antimicrobial resistance is one of the largest threats to global health and imposes substantial burdens in terms of morbidity, mortality, and economic costs. The gut is a key conduit for the genesis and spread of antimicrobial resistance in enteric bacterial pathogens. Distinct bacterial species that cause enteric disease can exist as invasive enteropathogens that immediately evoke gastrointestinal distress, or pathobionts that can arise from established bacterial commensals to inflict dysbiosis and disease. Furthermore, various environmental reservoirs and stressors facilitate the evolution and transmission of resistance. In this review, we present a comprehensive discussion on circulating resistance profiles and gene mobilization strategies of the most problematic species of enteric bacterial pathogens. Importantly, we present emerging approaches toward surveillance of pathogens and their resistance elements as well as promising treatment strategies that can circumvent common resistance mechanisms.
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Affiliation(s)
- M. J. Wallace
- Department of Pathology & Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA,The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - S. R. S. Fishbein
- Department of Pathology & Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA,The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - G. Dantas
- Department of Pathology & Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO, USA,The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA,Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA,Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO, USA,CONTACT G. Dantas Department of Pathology & Immunology, Division of Laboratory and Genomic Medicine, Washington University School of Medicine in St. Louis, St. Louis, MO
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Assessing the impacts on fetal dosimetry of the modelling of the placental transfers of xenobiotics in a pregnancy physiologically based pharmacokinetic model. Toxicol Appl Pharmacol 2020; 409:115318. [PMID: 33160985 DOI: 10.1016/j.taap.2020.115318] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 10/26/2020] [Accepted: 11/02/2020] [Indexed: 02/07/2023]
Abstract
The developmental origin of health and diseases theory supports the critical role of the fetal exposure to children's health. We developed a physiologically based pharmacokinetic model for human pregnancy (pPBPK) to simulate the maternal and fetal dosimetry throughout pregnancy. Four models of the placental exchanges of chemicals were assessed on ten chemicals for which maternal and fetal data were available. These models were calibrated using non-animal methods: in vitro (InV) or ex vivo (ExV) data, a semi-empirical relationship (SE), or the limitation by the placental perfusion (PL). They did not impact the maternal pharmacokinetics but provided different profiles in the fetus. The PL and InV models performed well even if the PL model overpredicted the fetal exposure for some substances. The SE and ExV models showed the lowest global performance and the SE model a tendency to underprediction. The comparison of the profiles showed that the PL model predicted an increase in the fetal exposure with the pregnancy age, whereas the ExV model predicted a decrease. For the SE and InV models, a small decrease was predicted during the second trimester. All models but the ExV one, presented the highest fetal exposure at the end of the third trimester. Global sensitivity analyses highlighted the predominant influence of the placental transfers on the fetal exposure, as well as the metabolic clearance and the fraction unbound. Finally, the four transfer models could be considered depending on the framework of the use of the pPBPK model and the availability of data or resources to inform their parametrization.
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Rossi R, Ciofalo M. An Updated Review on the Synthesis and Antibacterial Activity of Molecular Hybrids and Conjugates Bearing Imidazole Moiety. Molecules 2020; 25:molecules25215133. [PMID: 33158247 PMCID: PMC7663458 DOI: 10.3390/molecules25215133] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 10/25/2020] [Accepted: 10/26/2020] [Indexed: 01/28/2023] Open
Abstract
The rapid growth of serious infections caused by antibiotic resistant bacteria, especially the nosocomial ESKAPE pathogens, has been acknowledged by Governments and scientists and is one of the world's major health problems. Various strategies have been and are currently investigated and developed to reduce and/or delay the bacterial resistance. One of these strategies regards the design and development of antimicrobial hybrids and conjugates. This unprecedented critical review, in which our continuing interest in the synthesis and evaluation of the bioactivity of imidazole derivatives is testified, aims to summarise and comment on the results obtained from the end of the 1900s until February 2020 in studies conducted by numerous international research groups on the synthesis and evaluation of the antibacterial properties of imidazole-based molecular hybrids and conjugates in which the pharmacophoric constituents of these compounds are directly covalently linked or connected through a linker or spacer. In this review, significant attention was paid to summarise the strategies used to overcome the antibiotic resistance of pathogens whose infections are difficult to treat with conventional antibiotics. However, it does not include literature data on the synthesis and evaluation of the bioactivity of hybrids and conjugates in which an imidazole moiety is fused with a carbo- or heterocyclic subunit.
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Affiliation(s)
- Renzo Rossi
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi, 3, I-56124 Pisa, Italy
- Correspondence: (R.R.); (M.C.)
| | - Maurizio Ciofalo
- Dipartimento di Scienze Agrarie, Alimentari e Forestali, University of Palermo, Viale delle Scienze, Edificio 4, I-90128 Palermo, Italy
- Correspondence: (R.R.); (M.C.)
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Relationship between faecal metronidazole and lactoferrin concentrations to clinical response of patients with Clostridioides difficile. Eur J Clin Microbiol Infect Dis 2020; 39:1781-1784. [DOI: 10.1007/s10096-020-03895-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 04/02/2020] [Indexed: 01/04/2023]
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14
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Blake S, Thanissery R, Rivera AJ, Hixon MS, Lin M, Theriot CM, Janda KD. Salicylanilide Analog Minimizes Relapse of Clostridioides difficile Infection in Mice. J Med Chem 2020; 63:6898-6908. [PMID: 32482070 DOI: 10.1021/acs.jmedchem.0c00123] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Clostridioides difficile infection (CDI) causes serious and sometimes fatal symptoms like diarrhea and pseudomembranous colitis. Although antibiotics for CDI exist, they are either expensive or cause recurrence of the infection due to their altering the colonic microbiota, which is necessary to suppress the infection. Here, we leverage a class of known membrane-targeting compounds that we previously showed to have broad inhibitory activity across multiple Clostridioides difficile strains while preserving the microbiome to develop an efficacious agent. A new series of salicylanilides was synthesized, and the most potent analog was selected through an in vitro inhibitory assay to evaluate its pharmacokinetic parameters and potency in a CDI mouse model. The results revealed reduced recurrence of CDI and diminished disturbance of the microbiota in mice compared to standard-of-care vancomycin, thus paving the way for novel therapy that can potentially target the cell membrane of C. difficile to minimize relapse in the recovering patient.
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Affiliation(s)
- Steven Blake
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Rajani Thanissery
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27607, United States
| | - Alissa J Rivera
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27607, United States
| | - Mark S Hixon
- Mark S. Hixon Consulting, LLC., 11273 Spitfire Road, San Diego, California 92126, United States
| | - Mingliang Lin
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Casey M Theriot
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina 27607, United States
| | - Kim D Janda
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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15
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Pal R, Seleem MN. Screening of Natural Products and Approved Oncology Drug Libraries for Activity against Clostridioides difficile. Sci Rep 2020; 10:5966. [PMID: 32249833 PMCID: PMC7136261 DOI: 10.1038/s41598-020-63029-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/24/2020] [Indexed: 12/17/2022] Open
Abstract
Clostridioides difficile is the most common cause of healthcare-associated diarrhea. Infection of the gastrointestinal tract with this Gram-positive, obligate anaerobe can lead to potentially life-threatening conditions in the antibiotic-treated populace. New therapeutics are urgently needed to treat this infection and prevent its recurrence. Here, we screened two libraries from the National Cancer Institute, namely, the natural product set III library (117 compounds) and the approved oncology drugs set V library (114 compounds), against C. difficile. In the two libraries screened, 17 compounds from the natural product set III library and 7 compounds from the approved oncology drugs set V library were found to exhibit anticlostridial activity. The most potent FDA-approved drugs (mitomycin C and mithramycin A) and a promising natural product (aureomycin) were further screened against 20 clinical isolates of C. difficile. The anticancer drugs, mitomycin C (MIC50 = 0.25 μg/ml) and mithramycin A (MIC50 = 0.015 μg/ml), and the naturally derived tetracycline derivative, aureomycin (MIC50 = 0.06 μg/ml), exhibited potent activity against C. difficile strains. Mithramycin A and aureomycin were further found to inhibit toxin production by this pathogen. Given their efficacy, these compounds can provide a quick supplement to current treatment to address the unmet needs in treating C. difficile infection and preventing its recurrence.
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Affiliation(s)
- Rusha Pal
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Mohamed N Seleem
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA. .,Purdue Institute of Inflammation, Immunology, and Infectious Disease, West Lafayette, IN, 47907, USA.
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16
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Shao X, AbdelKhalek A, Abutaleb NS, Velagapudi UK, Yoganathan S, Seleem MN, Talele TT. Chemical Space Exploration around Thieno[3,2- d]pyrimidin-4(3 H)-one Scaffold Led to a Novel Class of Highly Active Clostridium difficile Inhibitors. J Med Chem 2019; 62:9772-9791. [PMID: 31584822 DOI: 10.1021/acs.jmedchem.9b01198] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Clostridium difficile infection (CDI) is the leading cause of healthcare-associated infection in the United States. Therefore, development of novel treatments for CDI is a high priority. Toward this goal, we began in vitro screening of a structurally diverse in-house library of 67 compounds against two pathogenic C. difficile strains (ATCC BAA 1870 and ATCC 43255), which yielded a hit compound, 2-methyl-8-nitroquinazolin-4(3H)-one (2) with moderate potency (MIC = 312/156 μM). Optimization of 2 gave lead compound 6a (2-methyl-7-nitrothieno[3,2-d]pyrimidin-4(3H)-one) with improved potency (MIC = 19/38 μM), selectivity over normal gut microflora, CC50s > 606 μM against mammalian cell lines, and acceptable stability in simulated gastric and intestinal fluid. Further optimization of 6a at C2-, N3-, C4-, and C7-positions resulted in a library of >50 compounds with MICs ranging from 3 to 800 μM against clinical isolates of C. difficile. Compound 8f (MIC = 3/6 μM) was identified as a promising lead for further optimization.
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Affiliation(s)
- Xuwei Shao
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences , St. John's University , Queens , New York 11439-0001 , United States
| | - Ahmed AbdelKhalek
- Department of Comparative Pathobiology , Purdue University College of Veterinary Medicine , West Lafayette , Indiana 47907-2027 , United States
| | - Nader S Abutaleb
- Department of Comparative Pathobiology , Purdue University College of Veterinary Medicine , West Lafayette , Indiana 47907-2027 , United States
| | - Uday Kiran Velagapudi
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences , St. John's University , Queens , New York 11439-0001 , United States
| | - Sabesan Yoganathan
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences , St. John's University , Queens , New York 11439-0001 , United States
| | - Mohamed N Seleem
- Department of Comparative Pathobiology , Purdue University College of Veterinary Medicine , West Lafayette , Indiana 47907-2027 , United States.,Purdue Institute of Inflammation, Immunology, and Infectious Disease , West Lafayette , Indiana 47907-2027 , United States
| | - Tanaji T Talele
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences , St. John's University , Queens , New York 11439-0001 , United States
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17
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Marreddy RKR, Wu X, Sapkota M, Prior AM, Jones JA, Sun D, Hevener KE, Hurdle JG. The Fatty Acid Synthesis Protein Enoyl-ACP Reductase II (FabK) is a Target for Narrow-Spectrum Antibacterials for Clostridium difficile Infection. ACS Infect Dis 2019; 5:208-217. [PMID: 30501172 DOI: 10.1021/acsinfecdis.8b00205] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Clostridium difficile infection (CDI) is an antibiotic-induced microbiota shift disease of the large bowel. While there is a need for narrow-spectrum CDI antibiotics, it is unclear which cellular proteins are appropriate drug targets to specifically inhibit C. difficile. We evaluated the enoyl-acyl carrier protein (ACP) reductase II (FabK), which catalyzes the final step of bacterial fatty acid biosynthesis. Bioinformatics showed that C. difficile uses FabK as its sole enoyl-ACP reductase, unlike several major microbiota species. The essentiality of fabK for C. difficile growth was confirmed by failure to delete this gene using ClosTron mutagenesis and by growth inhibition upon gene silencing with CRISPR interference antisense to fabK transcription or by blocking protein translation. Inhibition of C. difficile's FASII pathway could not be circumvented by supply of exogenous fatty acids, either during fabK's gene silencing or upon inhibition of the enzyme with a phenylimidazole-derived inhibitor (1). The inability of fatty acids to bypass FASII inhibition is likely due to the function of the transcriptional repressor FapR. Inhibition of FabK also inhibited spore formation, reflecting the enzyme's role in de novo fatty acid biosynthesis for the formation of spore membrane lipids. Compound 1 did not inhibit growth of key microbiota species. These findings suggest that C. difficile FabK is a druggable target for discovering narrow-spectrum anti- C. difficile drugs that treat CDI but avoid collateral damage to the gut microbiota.
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Affiliation(s)
- Ravi K. R. Marreddy
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, 2121 West Holcombe Boulevard, Houston, Texas 77030, United States
| | - Xiaoqian Wu
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, 2121 West Holcombe Boulevard, Houston, Texas 77030, United States
| | - Madhab Sapkota
- Department of Biology, University of Texas Arlington, 701 West Nedderman Drive, Arlington, Texas 76019, United States
| | - Allan M. Prior
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, 34 Rainbow Drive, Hilo, Hawaii 96720, United States
| | - Jesse A. Jones
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38105, United States
| | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, 34 Rainbow Drive, Hilo, Hawaii 96720, United States
| | - Kirk E. Hevener
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, Tennessee 38105, United States
| | - Julian G. Hurdle
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, 2121 West Holcombe Boulevard, Houston, Texas 77030, United States
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18
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Antibiotic susceptibility and resistance profiles of Romanian Clostridioides difficile isolates. REV ROMANA MED LAB 2018. [DOI: 10.2478/rrlm-2018-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
This study investigated the antibiotic susceptibility patterns and genetic resistance markers of 35 C. difficile strains isolated from patients with C. difficile infection. Vancomycin, metronidazole, tigecycline, teicoplanin, rifampicin, moxifloxacin, cefotaxime, tetracycline, erythromycin, clindamycin, chloramphenicol, linezolid and imipenem MICs were determined for toxigenic strains belonging to PCR ribotypes (PR) 012 (2), 014 (4), 017 (3), 018 (2), 027 (17), 046 (2), 087 (3) and 115 (2). Results showed vancomycin, metronidazole, tigecycline and teicoplanin to be active against all isolates. High resistance rates were noticed against cefotaxime (n = 35), clindamycin (n = 33), imipenem (n = 31), moxifloxacin (n = 25), erythromycin (n = 25) and rifampicin (n = 22). Linezolid-resistance was found in three isolates (PR 017/2, PR 012/1), showing complex resistance (7-9 antibiotics). PR 012, 017, 018, 027 and 046 isolates (n = 26) were resistant to 5-9 antibiotics. Twelve resistance profiles (2-9 antibiotics) were detected. Rifampicin-moxifloxacin-cefotaxime-erythromycin-clindamycin-imipenem-resistance was predominant, being expressed by 18 strains (PR 027/17, PR 018/1). PCR results suggested tetracycline-resistance to be induced by the gene tetM. Three tetM-positive isolates (PRs 012, 046), were also tndX-positive, suggesting the presence of a Tn5397-like element. Only two MLSB-resistant strains (PR 012) had the ermB gene and chloramphenicol-resistance determinant catD was not detected, leaving room for further investigating resistance mechanisms. Multidrug resistance could be attributed to most analysed strains, underlining, once more, the impact of wide-spectrum antimicrobial over prescription, still a tendency in our country, on transmission of antimicrobial resistance and emergence of epidemic C. difficile strains generating outbreaks.
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19
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Mu Q, Tavella VJ, Luo XM. Role of Lactobacillus reuteri in Human Health and Diseases. Front Microbiol 2018; 9:757. [PMID: 29725324 PMCID: PMC5917019 DOI: 10.3389/fmicb.2018.00757] [Citation(s) in RCA: 348] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Accepted: 04/04/2018] [Indexed: 12/13/2022] Open
Abstract
Lactobacillus reuteri (L. reuteri) is a well-studied probiotic bacterium that can colonize a large number of mammals. In humans, L. reuteri is found in different body sites, including the gastrointestinal tract, urinary tract, skin, and breast milk. The abundance of L. reuteri varies among different individuals. Several beneficial effects of L. reuteri have been noted. First, L. reuteri can produce antimicrobial molecules, such as organic acids, ethanol, and reuterin. Due to its antimicrobial activity, L. reuteri is able to inhibit the colonization of pathogenic microbes and remodel the commensal microbiota composition in the host. Second, L. reuteri can benefit the host immune system. For instance, some L. reuteri strains can reduce the production of pro-inflammatory cytokines while promoting regulatory T cell development and function. Third, bearing the ability to strengthen the intestinal barrier, the colonization of L. reuteri may decrease the microbial translocation from the gut lumen to the tissues. Microbial translocation across the intestinal epithelium has been hypothesized as an initiator of inflammation. Therefore, inflammatory diseases, including those located in the gut as well as in remote tissues, may be ameliorated by increasing the colonization of L. reuteri. Notably, the decrease in the abundance of L. reuteri in humans in the past decades is correlated with an increase in the incidences of inflammatory diseases over the same period of time. Direct supplementation or prebiotic modulation of L. reuteri may be an attractive preventive and/or therapeutic avenue against inflammatory diseases.
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Affiliation(s)
| | | | - Xin M. Luo
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, United States
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20
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Ang CW, Jarrad AM, Cooper MA, Blaskovich MAT. Nitroimidazoles: Molecular Fireworks That Combat a Broad Spectrum of Infectious Diseases. J Med Chem 2017; 60:7636-7657. [PMID: 28463485 DOI: 10.1021/acs.jmedchem.7b00143] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Infectious diseases claim millions of lives every year, but with the advent of drug resistance, therapeutic options to treat infections are inadequate. There is now an urgent need to develop new and effective treatments. Nitroimidazoles are a class of antimicrobial drugs that have remarkable broad spectrum activity against parasites, mycobacteria, and anaerobic Gram-positive and Gram-negative bacteria. While nitroimidazoles were discovered in the 1950s, there has been renewed interest in their therapeutic potential, particularly for the treatment of parasitic infections and tuberculosis. In this review, we summarize different classes of nitroimidazoles that have been described in the literature in the past five years, from approved drugs and clinical candidates to examples undergoing preclinical or early stage development. The relatively "nonspecific" mode of action and resistance mechanisms of nitromidazoles are discussed, and contemporary strategies to facilitate nitroimidazole drug development are highlighted.
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Affiliation(s)
- Chee Wei Ang
- The Institute for Molecular Bioscience, The University of Queensland , St Lucia, Queensland 4072, Australia
| | - Angie M Jarrad
- The Institute for Molecular Bioscience, The University of Queensland , St Lucia, Queensland 4072, Australia
| | - Matthew A Cooper
- The Institute for Molecular Bioscience, The University of Queensland , St Lucia, Queensland 4072, Australia
| | - Mark A T Blaskovich
- The Institute for Molecular Bioscience, The University of Queensland , St Lucia, Queensland 4072, Australia
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21
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Gooyit M, Janda KD. Reprofiled anthelmintics abate hypervirulent stationary-phase Clostridium difficile. Sci Rep 2016; 6:33642. [PMID: 27633064 PMCID: PMC5025651 DOI: 10.1038/srep33642] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/31/2016] [Indexed: 01/28/2023] Open
Abstract
Prolonged use of broad-spectrum antibiotics disrupts the indigenous gut microbiota, which consequently enables toxigenic Clostridium difficile species to proliferate and cause infection. The burden of C. difficile infections was exacerbated with the outbreak of hypervirulent strains that produce copious amounts of enterotoxins and spores. In recent past, membrane-active agents have generated a surge of interest due to their bactericidal property with a low propensity for resistance. In this study, we capitalized on the antimicrobial property and low oral bioavailability of salicylanilide anthelmintics (closantel, rafoxanide, niclosamide, oxyclozanide) to target the gut pathogen. By broth microdilution techniques, we determined the MIC values of the anthelmintics against 16 C. difficile isolates of defined PCR-ribotype. The anthelmintics broadly inhibited C. difficile growth in vitro via a membrane depolarization mechanism. Interestingly, the salicylanilides were bactericidal against logarithmic- and stationary-phase cultures of the BI/NAP1/027 strain 4118. The salicylanilides were poorly active against select gut commensals (Bacteroides, Bifidobacterium and Lactobacillus species), and were non-hemolytic and non-toxic to mammalian cell lines HepG2 and HEK 293T/17 within the range of their in vitro MICs and MBCs. The salicylanilide anthelmintics exhibit desirable properties for repositioning as anti-C. difficile agents.
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Affiliation(s)
- Major Gooyit
- Departments of Chemistry and Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, and The Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
| | - Kim D Janda
- Departments of Chemistry and Immunology and Microbial Science, The Skaggs Institute for Chemical Biology, and The Worm Institute of Research and Medicine (WIRM), The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, United States
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22
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Rifamycin Resistance in Clostridium difficile Is Generally Associated with a Low Fitness Burden. Antimicrob Agents Chemother 2016; 60:5604-7. [PMID: 27381389 DOI: 10.1128/aac.01137-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 06/25/2016] [Indexed: 12/22/2022] Open
Abstract
We characterized clinically occurring and novel mutations in the β subunit of RNA polymerase in Clostridium difficile (CdRpoB), conferring rifamycin (including rifaximin) resistance. The Arg505Lys substitution did not impose an in vitro fitness cost, which may be one reason for its dominance among rifamycin-resistant clinical isolates. These observations were supported through the structural modeling of CdRpoB. In general, most mutations lacked in vitro fitness costs, suggesting that rifamycin resistance may in some cases persist in the clinic.
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