1
|
Baldassare MA, Bhattacharjee D, Coles JD, Nelson S, McCollum CA, Seekatz AM. Butyrate enhances Clostridioides difficile sporulation in vitro. J Bacteriol 2023; 205:e0013823. [PMID: 37655912 PMCID: PMC10521354 DOI: 10.1128/jb.00138-23] [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: 04/24/2023] [Accepted: 07/11/2023] [Indexed: 09/02/2023] Open
Abstract
Short-chain fatty acids (SCFAs) are products of bacterial fermentation that help maintain important gut functions such as maintenance of the intestinal barrier, cell signaling, and immune homeostasis. The main SCFAs acetate, propionate, and butyrate have demonstrated beneficial effects for the host, including its importance in alleviating infections caused by pathogens such as Clostridioides difficile. Despite the potential role of SCFAs in mitigating C. difficile infection, their direct effect on C. difficile remains unclear. Through a set of in vitro experiments, we investigated how SCFAs influence C. difficile growth, sporulation, and toxin production. Similar to previous studies, we observed that butyrate decreased growth of C. difficile strain 630 in a dose-dependent manner. The presence of butyrate also increased C. difficile sporulation, with minimal increases in toxin production. RNA-Seq analysis validated our experimental results, demonstrating increased expression of sporulation-related genes in conjunction with changes in metabolic and regulatory genes, such as a putative carbon starvation protein, CstA. Collectively, these data suggest that butyrate may induce alternative C. difficile survival pathways, modifying its growth ability and virulence to persist in the gut environment. IMPORTANCE Several studies suggest that butyrate may modulate gut infections, such as reducing inflammation caused by the healthcare-associated Clostridioides difficile. While studies in both animal models and human studies correlate high levels of butyrate with reduced C. difficile burden, the direct impact of butyrate on C. difficile remains unclear. Our study demonstrates that butyrate directly influences C. difficile by increasing its sporulation and modifying its metabolism, potentially using butyrate as a biomarker to shift survival strategies in a changing gut environment. These data point to additional therapeutic approaches to combat C. difficile in a butyrate-directed manner.
Collapse
Affiliation(s)
| | - Disha Bhattacharjee
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Julian D. Coles
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Sydney Nelson
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - C. Alexis McCollum
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| | - Anna M. Seekatz
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
| |
Collapse
|
2
|
Baldassare MA, Bhattacharjee D, Coles JD, Nelson S, McCollum CA, Seekatz AM. Butyrate enhances Clostridioides difficile sporulation in vitro. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.538596. [PMID: 37163089 PMCID: PMC10168334 DOI: 10.1101/2023.04.27.538596] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Short chain fatty acids (SCFAs) are products of bacterial fermentation that help maintain important gut functions such as the intestinal barrier, signaling, and immune homeostasis. The main SCFAs acetate, propionate, and butyrate have demonstrated beneficial effects for the host, including importance in combatting infections caused by pathogens such as Clostridioides difficile . Despite the potential role of SCFAs in mitigating C. difficile infection, their direct effect on C. difficile remains unclear. Through a set of in vitro experiments, we investigated how SCFAs influence C. difficile growth, sporulation, and toxin production. Similar to previous studies, we observed that butyrate decreased growth of C. difficile strain 630 in a dose-dependent manner. The presence of butyrate also increased C. difficile sporulation, with minimal increases in toxin production. RNA-Seq analysis validated our experimental results, demonstrating increased expression of sporulation-related genes in conjunction with alternative metabolic and related C. difficile regulatory pathways, such as the carbon catabolite repressor, CcpA. Collectively, these data suggest that butyrate may signal alternative C. difficile metabolic pathways, thus modifying its growth and virulence to persist in the gut environment. IMPORTANCE Several studies suggest that butyrate may be important in alleviating gut infections, such as reducing inflammation caused by the healthcare-associated Clostridioides difficile . While studies in both animal models and human studies correlate high levels of butyrate with reduced C. difficile burden, the direct impact of butyrate on C. difficile remains unclear. Our study demonstrates that butyrate directly influences C. difficile by increasing its sporulation and modifying its metabolism, potentially using butyrate as a biomarker to shift survival strategies in a changing gut environment. These data point to additional therapeutic approaches to combat C. difficile in a butyrate-directed manner.
Collapse
|
3
|
Reinhardt T, Lee KM, Niederegger L, Hess CR, Sieber SA. Indolin-2-one Nitroimidazole Antibiotics Exhibit an Unexpected Dual Mode of Action. ACS Chem Biol 2022; 17:3077-3085. [PMID: 36259427 PMCID: PMC9679994 DOI: 10.1021/acschembio.2c00462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Nitroimidazoles such as metronidazole are used as anti-infective drugs against anaerobic bacteria. Upon in vivo reduction of the nitro group, reactive radicals damage DNA and proteins in the absence of oxygen. Unexpectedly, a recent study of nitroimidazoles linked to an indolin-2-one substituent revealed potent activities against aerobic bacteria. This suggests a different, yet undiscovered mode of action (MoA). To decipher this MoA, we first performed whole proteome analysis of compound-treated cells, revealing an upregulation of bacteriophage-associated proteins, indicative of DNA damage. Since DNA binding of the compound was not observed, we applied activity-based protein profiling (ABPP) for direct target discovery. Labeling studies revealed topoisomerase IV, an essential enzyme for DNA replication, as the most enriched hit in pathogenic Staphylococcus aureus cells. Subsequent topoisomerase assays confirmed the inhibition of DNA decatenation in the presence of indolin-2-one nitroimidazole with an activity comparable to ciprofloxacin, a known inhibitor of this enzyme. Furthermore, we determined significantly increased redox potentials of indolin-2-one nitroimidazoles compared to classic 5-nitroimidazoles such as metronidazole, which facilitates in vivo reduction. Overall, this study unravels that indolin-2-one-functionalized nitroimidazoles feature an unexpected dual MoA: first, the direct inhibition of the topoisomerase IV and second the classic nitroimidazole MoA of reductive bioactivation leading to damaging reactive species. Importantly, this dual MoA impairs resistance development. Given the clinical application of this compound class, the new mechanism could be a starting point to mitigate resistance.
Collapse
Affiliation(s)
- Till Reinhardt
- Center
for Functional Protein Assemblies (CPA), Department of Chemistry,
Chair of Organic Chemistry II, Technical
University of Munich, Ernst-Otto-Fischer Straße 8, D-85748 Garching, Germany
| | - Kyu M. Lee
- Center
for Functional Protein Assemblies (CPA), Department of Chemistry,
Chair of Organic Chemistry II, Technical
University of Munich, Ernst-Otto-Fischer Straße 8, D-85748 Garching, Germany,Therapeutics
& Biotechnology Division, Korea Research
Institute of Chemical Technology, Daejeon 34114, Korea
| | - Lukas Niederegger
- Department
of Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching, Germany
| | - Corinna R. Hess
- Department
of Chemistry and Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, D-85748 Garching, Germany
| | - Stephan A. Sieber
- Center
for Functional Protein Assemblies (CPA), Department of Chemistry,
Chair of Organic Chemistry II, Technical
University of Munich, Ernst-Otto-Fischer Straße 8, D-85748 Garching, Germany,
| |
Collapse
|
4
|
Bioenergetics and Reactive Nitrogen Species in Bacteria. Int J Mol Sci 2022; 23:ijms23137321. [PMID: 35806323 PMCID: PMC9266656 DOI: 10.3390/ijms23137321] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/24/2022] Open
Abstract
The production of reactive nitrogen species (RNS) by the innate immune system is part of the host’s defense against invading pathogenic bacteria. In this review, we summarize recent studies on the molecular basis of the effects of nitric oxide and peroxynitrite on microbial respiration and energy conservation. We discuss possible molecular mechanisms underlying RNS resistance in bacteria mediated by unique respiratory oxygen reductases, the mycobacterial bcc-aa3 supercomplex, and bd-type cytochromes. A complete picture of the impact of RNS on microbial bioenergetics is not yet available. However, this research area is developing very rapidly, and the knowledge gained should help us develop new methods of treating infectious diseases.
Collapse
|
5
|
Defenses of multidrug resistant pathogens against reactive nitrogen species produced in infected hosts. Adv Microb Physiol 2022; 80:85-155. [PMID: 35489794 DOI: 10.1016/bs.ampbs.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacterial pathogens have sophisticated systems that allow them to survive in hosts in which innate immunity is the frontline of defense. One of the substances produced by infected hosts is nitric oxide (NO) that together with its derived species leads to the so-called nitrosative stress, which has antimicrobial properties. In this review, we summarize the current knowledge on targets and protective systems that bacteria have to survive host-generated nitrosative stress. We focus on bacterial pathogens that pose serious health concerns due to the growing increase in resistance to currently available antimicrobials. We describe the role of nitrosative stress as a weapon for pathogen eradication, the detoxification enzymes, protein/DNA repair systems and metabolic strategies that contribute to limiting NO damage and ultimately allow survival of the pathogen in the host. Additionally, this systematization highlights the lack of available data for some of the most important human pathogens, a gap that urgently needs to be addressed.
Collapse
|
6
|
Dureja C, Olaitan AO, Hurdle JG. Mechanisms and impact of antimicrobial resistance in Clostridioides difficile. Curr Opin Microbiol 2022; 66:63-72. [PMID: 35077947 PMCID: PMC9064893 DOI: 10.1016/j.mib.2022.01.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/10/2021] [Accepted: 01/07/2022] [Indexed: 11/03/2022]
Abstract
The evolution of antimicrobial resistance in Clostridioides difficile has markedly shaped its epidemiology and detrimentally impacted patient care. C. difficile exhibits resistance to multiple classes of antimicrobials, due to accumulation of horizontally acquired resistance genes and de novo mutations to drug targets. Particularly worrying is that declines in clinical success of firstline CDI antimicrobials coincide with the spread of strains that are more resistant to these drugs. Yet, there is still much to learn regarding the prevalence of genetic elements in clinical isolates, their molecular mechanisms, and the extent to which this information can be translated to develop molecular diagnostics that improve antimicrobial prescribing and antimicrobial stewardship approaches for CDI. Thus, this perspective discusses current understanding and knowledge gaps of antimicrobial resistance mechanisms in C. difficile, emphasizing on CDI therapies.
Collapse
Affiliation(s)
- Chetna Dureja
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Department of Translational Medical Sciences, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, TX 77030, USA
| | - Abiola O Olaitan
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Department of Translational Medical Sciences, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, TX 77030, USA
| | - Julian G Hurdle
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Department of Translational Medical Sciences, Texas A&M Health Science Center, 2121 West Holcombe Blvd, Houston, TX 77030, USA.
| |
Collapse
|
7
|
Hashemian SMR, Pourhanifeh MH, Hamblin MR, Shahrzad MK, Mirzaei H. RdRp inhibitors and COVID-19: Is molnupiravir a good option? Biomed Pharmacother 2022; 146:112517. [PMID: 34902743 PMCID: PMC8654603 DOI: 10.1016/j.biopha.2021.112517] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 12/03/2021] [Accepted: 12/06/2021] [Indexed: 12/15/2022] Open
Abstract
Rapid changes in the viral genome allow viruses to evade threats posed by the host immune response or antiviral drugs, and can lead to viral persistence in the host cells. RNA-dependent RNA polymerase (RdRp) is an essential enzyme in RNA viruses, which is involved in RNA synthesis through the formation of phosphodiester bonds. Therefore, in RNA viral infections such as SARS-CoV-2, RdRp could be a crucial therapeutic target. The present review discusses the promising application of RdRp inhibitors, previously approved or currently being tested in human clinical trials, in the treatment of RNA virus infections. Nucleoside inhibitors (NIs) bind to the active site of RdRp, while nonnucleoside inhibitors (NNIs) bind to allosteric sites. Given the absence of highly effective drugs for the treatment of COVID-19, the discovery of an efficient treatment for this pandemic is an urgent concern for researchers around the world. We review the evidence for molnupiravir (MK-4482, EIDD-2801), an antiviral drug originally designed for Alphavirus infections, as a potential preventive and therapeutic agent for the management of COVID-19. At the beginning of this pandemic, molnupiravir was in preclinical development for seasonal influenza. When COVID-19 spread dramatically, the timeline for development was accelerated to focus on the treatment of this pandemic. Real time consultation with regulators took place to expedite this program. We summarize the therapeutic potential of RdRp inhibitors, and highlight molnupiravir as a new small molecule drug for COVID-19 treatment.
Collapse
Affiliation(s)
- Seyed Mohammad Reza Hashemian
- Chronic Respiratory Diseases Research Center (CRDRC), National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | - Michael R. Hamblin
- Laser Research Centre, Faculty of Health Science, University of Johannesburg, Doornfontein 2028, South Africa
| | - Mohammad Karim Shahrzad
- Department of Internal Medicine and Endocrinology, ShohadaeTajrish Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
| | - Hamed Mirzaei
- Student Research Committee, Kashan University of Medical Sciences, Kashan, Iran; Research Center for Biochemistry and Nutrition in Metabolic Diseases, Institute for Basic Sciences, Kashan University of Medical Sciences, Kashan, IR, Iran.
| |
Collapse
|
8
|
Correlated Transcriptional Responses Provide Insights into the Synergy Mechanisms of the Furazolidone, Vancomycin, and Sodium Deoxycholate Triple Combination in Escherichia coli. mSphere 2021; 6:e0062721. [PMID: 34494879 PMCID: PMC8550143 DOI: 10.1128/msphere.00627-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Effective therapeutic options are urgently needed to tackle antibiotic resistance. Furazolidone (FZ), vancomycin (VAN), and sodium deoxycholate (DOC) show promise as their combination can synergistically inhibit the growth of, and kill, multidrug-resistant Gram-negative bacteria that are classified as critical priority by the World Health Organization. Here, we investigated the mechanisms of action and synergy of this drug combination using a transcriptomics approach in the model bacterium Escherichia coli. We show that FZ and DOC elicit highly similar gene perturbations indicative of iron starvation, decreased respiration and metabolism, and translational stress. In contrast, VAN induced envelope stress responses, in agreement with its known role in peptidoglycan synthesis inhibition. FZ induces the SOS response consistent with its DNA-damaging effects, but we demonstrate that using FZ in combination with the other two compounds enables lower dosages and largely mitigates its mutagenic effects. Based on the gene expression changes identified, we propose a synergy mechanism where the combined effects of FZ, VAN, and DOC amplify damage to Gram-negative bacteria while simultaneously suppressing antibiotic resistance mechanisms. IMPORTANCE Synergistic antibiotic combinations are a promising alternative strategy for developing effective therapies for multidrug-resistant bacterial infections. The synergistic combination of the existing antibiotics nitrofurans and vancomycin with sodium deoxycholate shows promise in inhibiting and killing multidrug-resistant Gram-negative bacteria. We examined the mechanism of action and synergy of these three antibacterials and proposed a mechanistic basis for their synergy. Our results highlight much-needed mechanistic information necessary to advance this combination as a potential therapy.
Collapse
|
9
|
Lokhande AS, Devarajan PV. A review on possible mechanistic insights of Nitazoxanide for repurposing in COVID-19. Eur J Pharmacol 2021; 891:173748. [PMID: 33227285 PMCID: PMC7678434 DOI: 10.1016/j.ejphar.2020.173748] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 11/06/2020] [Accepted: 11/17/2020] [Indexed: 02/06/2023]
Abstract
The global pandemic of Coronavirus Disease 2019 (COVID-19) has brought the world to a grinding halt. A major cause of concern is the respiratory distress associated mortality attributed to the cytokine storm. Despite myriad rapidly approved clinical trials with repurposed drugs, and time needed to develop a vaccine, accelerated search for repurposed therapeutics is still ongoing. In this review, we present Nitazoxanide a US-FDA approved antiprotozoal drug, as one such promising candidate. Nitazoxanide which is reported to exert broad-spectrum antiviral activity against various viral infections, revealed good in vitro activity against SARS-CoV-2 in cell culture assays, suggesting potential for repurposing in COVID-19. Furthermore, nitazoxanide displays the potential to boost host innate immune responses and thereby tackle the life-threatening cytokine storm. Possibilities of improving lung, as well as multiple organ damage and providing value addition to COVID-19 patients with comorbidities, are other important facets of the drug. The review juxtaposes the role of nitazoxanide in fighting COVID-19 pathogenesis at multiple levels highlighting the great promise the drug exhibits. The in silico data and in vitro efficacy in cell lines confirms the promise of nitazoxanide. Several approved clinical trials world over further substantiate leveraging nitazoxanide for COVID-19 therapy.
Collapse
Affiliation(s)
- Amit S Lokhande
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, 400019, Maharashtra, India
| | - Padma V Devarajan
- Department of Pharmaceutical Sciences and Technology, Institute of Chemical Technology, N. P. Marg, Matunga, Mumbai, 400019, Maharashtra, India.
| |
Collapse
|
10
|
Koventhan C, Vinothkumar V, Chen SM. Development of an electrochemical sensor based on a cobalt oxide/tin oxide composite for determination of antibiotic drug ornidazole. NEW J CHEM 2021. [DOI: 10.1039/d1nj01345a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
A schematic illustration of the electrochemical performance towards sensing of ODZ at the Co3O4/SnO2/GCE.
Collapse
Affiliation(s)
- Chelliah Koventhan
- Department of Chemical Engineering and Biotechnology
- College of Engineering
- National Taipei University of Technology
- Taipei 10608
- Taiwan
| | - Venkatachalam Vinothkumar
- Department of Chemical Engineering and Biotechnology
- College of Engineering
- National Taipei University of Technology
- Taipei 10608
- Taiwan
| | - Shen-Ming Chen
- Department of Chemical Engineering and Biotechnology
- College of Engineering
- National Taipei University of Technology
- Taipei 10608
- Taiwan
| |
Collapse
|
11
|
Chromosomal Resistance to Metronidazole in Clostridioides difficile Can Be Mediated by Epistasis between Iron Homeostasis and Oxidoreductases. Antimicrob Agents Chemother 2020; 64:AAC.00415-20. [PMID: 32457109 DOI: 10.1128/aac.00415-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/21/2020] [Indexed: 12/17/2022] Open
Abstract
Chromosomal resistance to metronidazole has emerged in clinical Clostridioides difficile isolates, but the genetic mechanisms remain unclear. This is further hindered by the inability to generate spontaneous metronidazole-resistant mutants in the lab to interpret genetic variations in clinical isolates. We therefore constructed a mismatch repair mutator in nontoxigenic ATCC 700057 to survey the mutational landscape for de novo resistance mechanisms. In separate experimental evolutions, the mutator adopted a deterministic path to resistance, with truncation of the ferrous iron transporter FeoB1 as a first-step mechanism of low-level resistance. Deletion of feoB1 in ATCC 700057 reduced the intracellular iron content, appearing to shift cells toward flavodoxin-mediated oxidoreductase reactions, which are less favorable for metronidazole's cellular action. Higher-level resistance evolved from sequential acquisition of mutations to catalytic domains of pyruvate-ferredoxin/flavodoxin oxidoreductase (PFOR; encoded by nifJ), a synonymous codon change to putative xdh (xanthine dehydrogenase; encoded by CD630_31770), likely affecting mRNA stability, and last, frameshift and point mutations that inactivated the iron-sulfur cluster regulator (IscR). Gene silencing of nifJ, xdh, or iscR with catalytically dead Cas9 revealed that resistance involving these genes occurred only when feoB1 was inactivated; i.e., resistance was seen only in the feoB1 deletion mutant and not in the isogenic wild-type (WT) parent. Interestingly, metronidazole resistance in C. difficile infection (CDI)-associated strains carrying mutations in nifJ was reduced upon gene complementation. This observation supports the idea that mutation in PFOR is one mechanism of metronidazole resistance in clinical strains. Our findings indicate that metronidazole resistance in C. difficile is complex, involving multigenetic mechanisms that could intersect with iron-dependent and oxidoreductive metabolic pathways.
Collapse
|
12
|
Repurposing the Antiamoebic Drug Diiodohydroxyquinoline for Treatment of Clostridioides difficile Infections. Antimicrob Agents Chemother 2020; 64:AAC.02115-19. [PMID: 32253206 DOI: 10.1128/aac.02115-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 03/27/2020] [Indexed: 12/15/2022] Open
Abstract
Clostridioides difficile, the leading cause of nosocomial infections, is an urgent health threat worldwide. The increased incidence and severity of disease, the high recurrence rates, and the dearth of effective anticlostridial drugs have created an urgent need for new therapeutic agents. In an effort to discover new drugs for the treatment of Clostridioides difficile infections (CDIs), we investigated a panel of FDA-approved antiparasitic drugs against C. difficile and identified diiodohydroxyquinoline (DIHQ), an FDA-approved oral antiamoebic drug. DIHQ exhibited potent activity against 39 C. difficile isolates, inhibiting growth of 50% and 90% of these isolates at concentrations of 0.5 μg/ml and 2 μg/ml, respectively. In a time-kill assay, DIHQ was superior to vancomycin and metronidazole, reducing a high bacterial inoculum by 3 log10 within 6 h. Furthermore, DIHQ reacted synergistically with vancomycin and metronidazole against C. difficile in vitro. Moreover, at subinhibitory concentrations, DIHQ was superior to vancomycin and metronidazole in inhibiting two key virulence factors of C. difficile, toxin production and spore formation. Additionally, DIHQ did not inhibit the growth of key species that compose the host intestinal microbiota, such as Bacteroides, Bifidobacterium, and Lactobacillus spp. Collectively, our results indicate that DIHQ is a promising anticlostridial drug that warrants further investigation as a new therapeutic for CDIs.
Collapse
|
13
|
Wang H, Bo X, Zhou M, Guo L. DUT-67 and tubular polypyrrole formed a cross-linked network for electrochemical detection of nitrofurazone and ornidazole. Anal Chim Acta 2020; 1109:1-8. [DOI: 10.1016/j.aca.2020.03.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/22/2020] [Accepted: 03/02/2020] [Indexed: 12/14/2022]
|
14
|
AbdelKhalek A, Mohammad H, Mayhoub AS, Seleem MN. Screening for potent and selective anticlostridial leads among FDA-approved drugs. J Antibiot (Tokyo) 2020; 73:392-409. [PMID: 32132676 DOI: 10.1038/s41429-020-0288-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 12/16/2019] [Accepted: 02/05/2020] [Indexed: 12/17/2022]
Abstract
Clostridium difficile is a leading cause of morbidity and mortality particularly in hospital settings. In addition, treatment is very challenging due to the scarcity of effective therapeutic options. Thus, there remains an unmet need to identify new therapeutic agents capable of treating C. difficile infections. In the current study, we screened two FDA-approved drug libraries against C. difficile. Out of almost 3200 drugs screened, 50 drugs were capable of inhibiting the growth of C. difficile. Remarkably, some of the potent inhibitors have never been reported before and showed activity in a clinically achievable range. Structure-activity relationship analysis of the active hits clustered the potent inhibitors into four chemical groups; nitroimidazoles (MIC50 = 0.06-2.7 μM), salicylanilides (MIC50 = 0.2-0.6 μM), imidazole antifungals (MIC50 = 4.8-11.6 μM), and miscellaneous group (MIC50 = 0.4-22.2 μM). The most potent drugs from the initial screening were further evaluated against additional clinically relevant strains of C. difficile. Moreover, we tested the activity of potent inhibitors against representative strains of human normal gut microbiota to investigate the selectivity of the inhibitors towards C. difficile. Overall, this study provides a platform that could be used for further development of potent and selective anticlostridial antibiotics.
Collapse
Affiliation(s)
- Ahmed AbdelKhalek
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Haroon Mohammad
- Department of Comparative Pathobiology, College of Veterinary Medicine, Purdue University, West Lafayette, IN, 47907, USA
| | - Abdelrahman S Mayhoub
- Department of Pharmaceutical Organic Chemistry, College of Pharmacy, Al-Azhar University, Cairo, 11884, Egypt.,University of Science and Technology, Zewail City of Science and Technology, Giza, 12578, Egypt
| | - 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.
| |
Collapse
|
15
|
Le VVH, Olivera C, Spagnuolo J, Davies IG, Rakonjac J. In vitro synergy between sodium deoxycholate and furazolidone against enterobacteria. BMC Microbiol 2020; 20:5. [PMID: 31906851 PMCID: PMC6945529 DOI: 10.1186/s12866-019-1668-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 11/29/2019] [Indexed: 12/11/2022] Open
Abstract
Background Antimicrobial combinations have been proven as a promising approach in the confrontation with multi-drug resistant bacterial pathogens. In the present study, we identify and characterize a synergistic interaction of broad-spectrum nitroreductase-activated prodrugs 5-nitrofurans, with a secondary bile salt, sodium deoxycholate (DOC) in growth inhibition and killing of enterobacteria. Results Using checkerboard assay, we show that combination of nitrofuran furazolidone (FZ) and DOC generates a profound synergistic effect on growth inhibition in several enterobacterial species including Escherichia coli, Salmonella enterica, Citrobacter gillenii and Klebsiella pneumoniae. The Fractional Inhibitory Concentration Index (FICI) for DOC-FZ synergy ranges from 0.125 to 0.35 that remains unchanged in an ampicillin-resistant E. coli strain containing a β-lactamase-producing plasmid. Findings from the time-kill assay further highlight the synergy with respect to bacterial killing in E. coli and Salmonella. We further characterize the mechanism of synergy in E. coli K12, showing that disruption of the tolC or acrA genes that encode components of multidrug efflux pumps causes, respectively, a complete or partial loss, of the DOC-FZ synergy. This finding indicates the key role of TolC-associated efflux pumps in the DOC-FZ synergy. Overexpression of nitric oxide-detoxifying enzyme Hmp results in a three-fold increase in FICI for DOC-FZ interaction, suggesting a role of nitric oxide in the synergy. We further demonstrate that DOC-FZ synergy is largely independent of NfsA and NfsB, the two major activation enzymes of the nitrofuran prodrugs. Conclusions This study is to our knowledge the first report of nitrofuran-deoxycholate synergy against Gram-negative bacteria, offering potential applications in antimicrobial therapeutics. The mechanism of DOC-FZ synergy involves FZ-mediated inhibition of TolC-associated efflux pumps that normally remove DOC from bacterial cells. One possible route contributing to that effect is via FZ-mediated nitric oxide production.
Collapse
Affiliation(s)
- Vuong Van Hung Le
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Catrina Olivera
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Julian Spagnuolo
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.,Present Address: Department of Biomedicine, University Hospital Basel, 4031, Basel, Switzerland
| | - Ieuan G Davies
- New Zealand Pharmaceuticals Ltd, Palmerston North, New Zealand
| | - Jasna Rakonjac
- School of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
| |
Collapse
|
16
|
Cherian PT, Wu X, Yang L, Scarborough JS, Singh AP, Alam ZA, Lee RE, Hurdle JG. Gastrointestinal localization of metronidazole by a lactobacilli-inspired tetramic acid motif improves treatment outcomes in the hamster model of Clostridium difficile infection. J Antimicrob Chemother 2015; 70:3061-9. [PMID: 26286574 DOI: 10.1093/jac/dkv231] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 07/07/2015] [Indexed: 01/30/2023] Open
Abstract
OBJECTIVES Metronidazole, a mainstay treatment for Clostridium difficile infection (CDI), is often ineffective for severe CDI. Whilst this is thought to arise from suboptimal levels of metronidazole in the colon due to rapid absorption, empirical validation is lacking. In contrast, reutericyclin, an antibacterial tetramic acid from Lactobacillus reuteri, concentrates in the gastrointestinal tract. In this study, we modified metronidazole with reutericyclin's tetramic acid motif to obtain non-absorbed compounds, enabling assessment of the impact of pharmacokinetics on treatment outcomes. METHODS A series of metronidazole-bearing tetramic acid substituents were synthesized and evaluated in terms of anti-C. difficile activities, gastric permeability, in vivo pharmacokinetics, efficacy in the hamster model of CDI and mode of action. RESULTS Most compounds were absorbed less than metronidazole in cell-based Caco-2 permeability assays. In hamsters, lead compounds compartmentalized in the colon rather than the bloodstream with negligible levels detected in the blood, in direct contrast with metronidazole, which was rapidly absorbed into the blood and was undetectable in caecum. Accordingly, four leads were more efficacious (P < 0.05) than metronidazole in C. difficile-infected animals. Improved efficacy was not due to an alternative mode of action, as the leads retained the mode of action of metronidazole. CONCLUSIONS This study provides the clearest empirical evidence that the high absorption of metronidazole lowers treatment outcomes for CDI and suggests a role for the tetramic acid motif for colon-specific drug delivery. This approach also has the potential to lower systemic toxicity and drug interactions of nitroheterocyclic drugs for treating gastrointestine-specific diseases.
Collapse
Affiliation(s)
- Philip T Cherian
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xiaoqian Wu
- Department of Biology, University of Texas, Arlington, TX 76019, USA Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Lei Yang
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jerrod S Scarborough
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Aman P Singh
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA Biomedical Sciences Program, Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Zahidul A Alam
- Department of Biology, University of Texas, Arlington, TX 76019, USA
| | - Richard E Lee
- Department of Chemical Biology and Therapeutics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Julian G Hurdle
- Department of Biology, University of Texas, Arlington, TX 76019, USA Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA Department of Microbial and Molecular Pathogenesis, Texas A&M Health Science Center, College of Medicine, Bryan, TX 77807, USA
| |
Collapse
|
17
|
Ansell BRE, McConville MJ, Ma'ayeh SY, Dagley MJ, Gasser RB, Svärd SG, Jex AR. Drug resistance in Giardia duodenalis. Biotechnol Adv 2015; 33:888-901. [PMID: 25922317 DOI: 10.1016/j.biotechadv.2015.04.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Revised: 04/21/2015] [Accepted: 04/21/2015] [Indexed: 02/07/2023]
Abstract
Giardia duodenalis is a microaerophilic parasite of the human gastrointestinal tract and a major contributor to diarrheal and post-infectious chronic gastrointestinal disease world-wide. Treatment of G. duodenalis infection currently relies on a small number of drug classes. Nitroheterocyclics, in particular metronidazole, have represented the front line treatment for the last 40 years. Nitroheterocyclic-resistant G. duodenalis have been isolated from patients and created in vitro, prompting considerable research into the biomolecular mechanisms of resistance. These compounds are redox-active and are believed to damage proteins and DNA after being activated by oxidoreductase enzymes in metabolically active cells. In this review, we explore the molecular phenotypes of nitroheterocyclic-resistant G. duodenalis described to date in the context of the protist's unusual glycolytic and antioxidant systems. We propose that resistance mechanisms are likely to extend well beyond currently described resistance-associated enzymes (i.e., pyruvate ferredoxin oxidoreductases and nitroreductases), to include NAD(P)H- and flavin-generating pathways, and possibly redox-sensitive epigenetic regulation. Mechanisms that allow G. duodenalis to tolerate oxidative stress may lead to resistance against both oxygen and nitroheterocyclics, with implications for clinical control. The present review highlights the potential for systems biology tools and advanced bioinformatics to further investigate the multifaceted mechanisms of nitroheterocyclic resistance in this important pathogen.
Collapse
Affiliation(s)
- Brendan R E Ansell
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia.
| | - Malcolm J McConville
- Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Showgy Y Ma'ayeh
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, SE-751 24 Uppsala, Sweden
| | - Michael J Dagley
- Bio21 Institute, University of Melbourne, 30 Flemington Rd, Parkville, VIC 3010, Australia
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Biomedical Center, Uppsala University, Box 596, SE-751 24 Uppsala, Sweden
| | - Aaron R Jex
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Cnr Park Dr and Flemington Rd, Parkville, VIC 3010, Australia
| |
Collapse
|