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Yip C, Phan JR, Abel-Santos E. Mechanism of germination inhibition of Clostridioides difficile spores by an aniline substituted cholate derivative (CaPA). J Antibiot (Tokyo) 2023; 76:335-345. [PMID: 37016015 PMCID: PMC10406169 DOI: 10.1038/s41429-023-00612-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 02/28/2023] [Accepted: 03/07/2023] [Indexed: 04/06/2023]
Abstract
Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea and has been declared an urgent threat by the CDC. C. difficile forms dormant and resistant spores that serve as infectious vehicles for CDI. To cause disease, C. difficile spores recognize taurocholate and glycine to trigger the germination process. In contrast to other sporulating bacteria, C. difficile spores are postulated to use a protease complex, CspABC, to recognize its germinants. Since spore germination is required for infection, we have developed anti-germination approaches for CDI prophylaxis. Previously, the bile salt analog CaPA (an aniline-substituted cholic acid) was shown to block spore germination and protect rodents from CDI caused by multiple C. difficile strains and isolates. In this study, we found that CaPA is an alternative substrate inhibitor of C. difficile spore germination. By competing with taurocholate for binding, CaPA delays C. difficile spore germination and reduces spore viability, thus diminishing the number of outgrowing vegetative bacteria. We hypothesize that the reduction of toxin-producing bacterial burden explains CaPA's protective activity against murine CDI. Previous data combined with our results suggests that CaPA binds tightly to C. difficile spores in a CspC-dependent manner and irreversibly traps spores in an alternative, time-delayed, and low yield germination pathway. Our results are also consistent with kinetic data suggesting the existence of at least two distinct bile salt binding sites in C. difficile spores.
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Affiliation(s)
- Christopher Yip
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA
| | - Jacqueline R Phan
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA.
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2
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Amponsah J, Tegg RS, Thangavel T, Wilson CR. Moments of weaknesses - exploiting vulnerabilities between germination and encystment in the Phytomyxea. Biol Rev Camb Philos Soc 2021; 96:1603-1615. [PMID: 33821562 DOI: 10.1111/brv.12717] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 11/30/2022]
Abstract
Attempts at management of diseases caused by protozoan plant parasitic Phytomyxea have often been ineffective. The dormant life stage is characterised by long-lived highly robust resting spores that are largely impervious to chemical treatment and environmental stress. This review explores some life stage weaknesses and highlights possible control measures associated with resting spore germination and zoospore taxis. With phytomyxid pathogens of agricultural importance, zoospore release from resting spores is stimulated by plant root exudates. On germination, the zoospores are attracted to host roots by chemoattractant components of root exudates. Both the relatively metabolically inactive resting spore and motile zoospore need to sense the chemical environment to determine the suitability of these germination stimulants or attractants respectively, before they can initiate an appropriate response. Blocking such sensing could inhibit resting spore germination or zoospore taxis. Conversely, the short life span and the vulnerability of zoospores to the environment require them to infect their host within a few hours after release. Identifying a mechanism or conditions that could synchronise resting spore germination in the absence of host plants could lead to diminished pathogen populations in the field.
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Affiliation(s)
- Jonathan Amponsah
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia.,Biotechnology and Nuclear Agricultural Research Institute Centre, Ghana Atomic Energy Commission, P.O. Box LG 80, Legon, Accra, Ghana
| | - Robert S Tegg
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
| | - Tamilarasan Thangavel
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
| | - Calum R Wilson
- Tasmanian Institute of Agriculture, New Town Research Laboratories, University of Tasmania, 13 St Johns Avenue, New Town, TAS, 7008, Australia
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Alvarado I, Margotta JW, Aoki MM, Flores F, Agudelo F, Michel G, Elekonich MM, Abel-Santos E. Inhibitory effect of indole analogs against Paenibacillus larvae, the causal agent of American foulbrood disease. JOURNAL OF INSECT SCIENCE (ONLINE) 2017; 17:4469416. [PMID: 29117379 PMCID: PMC7206643 DOI: 10.1093/jisesa/iex080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Indexed: 06/07/2023]
Abstract
Paenibacillus larvae, a Gram-positive bacterium, causes American foulbrood (AFB) in honey bee larvae (Apis mellifera Linnaeus [Hymenoptera: Apidae]). P. larvae spores exit dormancy in the gut of bee larvae, the germinated cells proliferate, and ultimately bacteremia kills the host. Hence, spore germination is a required step for establishing AFB disease. We previously found that P. larvae spores germinate in response to l-tyrosine plus uric acid in vitro. Additionally, we determined that indole and phenol blocked spore germination. In this work, we evaluated the antagonistic effect of 35 indole and phenol analogs and identified strong inhibitors of P. larvae spore germination in vitro. We further tested the most promising candidate, 5-chloroindole, and found that it significantly reduced bacterial proliferation. Finally, feeding artificial worker jelly containing anti-germination compounds to AFB-exposed larvae significantly decreased AFB infection in laboratory-reared honey bee larvae. Together, these results suggest that inhibitors of P. larvae spore germination could provide another method to control AFB.
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Affiliation(s)
- Israel Alvarado
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Joseph W Margotta
- School of Life Sciences, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Mai M Aoki
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Fernando Flores
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Fresia Agudelo
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Guillermo Michel
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154
| | - Michelle M Elekonich
- Directorate for Biological Sciences, National Science Foundation, 2415 Eisenhower Avenue, Alexandria, VA 22314, and
| | - Ernesto Abel-Santos
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, Las Vegas, NV 89154
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4
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Stoltz KL, Erickson R, Staley C, Weingarden AR, Romens E, Steer CJ, Khoruts A, Sadowsky MJ, Dosa PI. Synthesis and Biological Evaluation of Bile Acid Analogues Inhibitory to Clostridium difficile Spore Germination. J Med Chem 2017; 60:3451-3471. [PMID: 28402634 DOI: 10.1021/acs.jmedchem.7b00295] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Standard antibiotic-based strategies for the treatment of Clostridium difficile infections disrupt indigenous microbiota and commonly fail to eradicate bacterial spores, two key factors that allow recurrence of infection. As an alternative approach to controlling C. difficile infection, a series of bile acid derivatives have been prepared that inhibit taurocholate-induced spore germination. These analogues have been evaluated in a highly virulent NAP1 strain using optical density and phase-contrast microscopy assays. Heterocycle substitutions at C24 were well-tolerated and several tetrazole-containing derivatives were highly potent inhibitors in both assays, with complete inhibition of spore germination observed at 10-25 μM. To limit intestinal absorption, C7-sulfated analogues designed to avoid active and passive transport pathways were prepared. One of these derivatives, compound 21b, was found to be a potent inhibitor of C. difficile spore germination and poorly permeable in a Caco-2 model of intestinal epithelial absorption, suggesting that it is likely to be gut-restricted.
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Affiliation(s)
- Kristen L Stoltz
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota , 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
| | - Raymond Erickson
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Christopher Staley
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Alexa R Weingarden
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States.,Department of Microbiology and Immunology, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - Erin Romens
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States
| | - Clifford J Steer
- Departments of Medicine and Genetics, Cell Biology, and Development, University of Minnesota , VFW Cancer Research Center, 406 Harvard Street, Minneapolis, Minnesota, United States
| | - Alexander Khoruts
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States.,Department of Medicine, Division of Gastroenterology, University of Minnesota , Minneapolis, Minnesota 55414, United States.,Center for Immunology, University of Minnesota , Minneapolis, Minnesota 55414, United States
| | - Michael J Sadowsky
- BioTechnology Institute, University of Minnesota , 1479 Gortner Avenue, St. Paul, Minnesota 55108, United States.,Department of Soil, Water & Climate, University of Minnesota , St. Paul, Minnesota 55108, United States
| | - Peter I Dosa
- Institute for Therapeutics Discovery and Development, Department of Medicinal Chemistry, University of Minnesota , 717 Delaware Street SE, Minneapolis, Minnesota 55414, United States
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Alvarado I, Phui A, Elekonich MM, Abel-Santos E. Requirements for in vitro germination of Paenibacillus larvae spores. J Bacteriol 2013; 195:1005-11. [PMID: 23264573 PMCID: PMC3571325 DOI: 10.1128/jb.01958-12] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Accepted: 12/12/2012] [Indexed: 01/03/2023] Open
Abstract
Paenibacillus larvae is the causative agent of American foulbrood (AFB), a disease affecting honey bee larvae. First- and second-instar larvae become infected when they ingest food contaminated with P. larvae spores. The spores then germinate into vegetative cells that proliferate in the midgut of the honey bee. Although AFB affects honey bees only in the larval stage, P. larvae spores can be distributed throughout the hive. Because spore germination is critical for AFB establishment, we analyzed the requirements for P. larvae spore germination in vitro. We found that P. larvae spores germinated only in response to l-tyrosine plus uric acid under physiologic pH and temperature conditions. This suggests that the simultaneous presence of these signals is necessary for spore germination in vivo. Furthermore, the germination profiles of environmentally derived spores were identical to those of spores from a biochemically typed strain. Because l-tyrosine and uric acid are the only required germinants in vitro, we screened amino acid and purine analogs for their ability to act as antagonists of P. larvae spore germination. Indole and phenol, the side chains of tyrosine and tryptophan, strongly inhibited P. larvae spore germination. Methylation of the N-1 (but not the C-3) position of indole eliminated its ability to inhibit germination. Identification of the activators and inhibitors of P. larvae spore germination provides a basis for developing new tools to control AFB.
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Affiliation(s)
| | - Andy Phui
- Department of Chemistry, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
| | | | - Ernesto Abel-Santos
- Department of Chemistry, University of Nevada, Las Vegas, Las Vegas, Nevada, USA
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6
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Howerton A, Patra M, Abel-Santos E. A new strategy for the prevention of Clostridium difficile infection. J Infect Dis 2013; 207:1498-504. [PMID: 23420906 DOI: 10.1093/infdis/jit068] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Clostridium difficile infection (CDI) is a leading cause of antibiotic-associated diarrhea. The infective form of C. difficile is the spore, but the vegetative bacterium causes the disease. Because C. difficile spore germination is required for symptomatic infection, antigermination approaches could lead to the prevention of CDI. We recently reported that CamSA, a bile salt analog, inhibits C. difficile spore germination in vitro. METHODS Mice infected with massive inocula of C. difficile spores were treated with different concentrations of CamSA and monitored for CDI signs. C. difficile spore and vegetative cells were counted in feces from infected mice. RESULTS A single 50-mg/kg dose of CamSA prevented CDI in mice without any observable toxicity. Lower CamSA doses resulted in delayed CDI onset and less severe signs of disease. Ingested C. difficile spores were quantitatively recovered from feces of CamSA-protected mice. CONCLUSIONS Our results support a mechanism whereby the antigermination effect of CamSA is responsible for preventing CDI signs. This approach represents a new paradigm in CDI treatment. Instead of further compromising the microbiota of CDI patients with strong antibiotics, antigermination therapy could serve as a microbiota surrogate to curtail C. difficile colonization of antibiotic-treated patients.
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Affiliation(s)
- Amber Howerton
- Department of Chemistry, University of Nevada, Las Vegas, NV 89154, USA
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7
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Rogers MS, Cryan LM, Habeshian KA, Bazinet L, Caldwell TP, Ackroyd PC, Christensen KA. A FRET-based high throughput screening assay to identify inhibitors of anthrax protective antigen binding to capillary morphogenesis gene 2 protein. PLoS One 2012; 7:e39911. [PMID: 22768167 PMCID: PMC3386954 DOI: 10.1371/journal.pone.0039911] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 06/03/2012] [Indexed: 11/18/2022] Open
Abstract
Anti-angiogenic therapies are effective for the treatment of cancer, a variety of ocular diseases, and have potential benefits in cardiovascular disease, arthritis, and psoriasis. We have previously shown that anthrax protective antigen (PA), a non-pathogenic component of anthrax toxin, is an inhibitor of angiogenesis, apparently as a result of interaction with the cell surface receptors capillary morphogenesis gene 2 (CMG2) protein and tumor endothelial marker 8 (TEM8). Hence, molecules that bind the anthrax toxin receptors may be effective to slow or halt pathological vascular growth. Here we describe development and testing of an effective homogeneous steady-state fluorescence resonance energy transfer (FRET) high throughput screening assay designed to identify molecules that inhibit binding of PA to CMG2. Molecules identified in the screen can serve as potential lead compounds for the development of anti-angiogenic and anti-anthrax therapies. The assay to screen for inhibitors of this protein–protein interaction is sensitive and robust, with observed Z' values as high as 0.92. Preliminary screens conducted with a library of known bioactive compounds identified tannic acid and cisplatin as inhibitors of the PA-CMG2 interaction. We have confirmed that tannic acid both binds CMG2 and has anti-endothelial properties. In contrast, cisplatin appears to inhibit PA-CMG2 interaction by binding both PA and CMG2, and observed cisplatin anti-angiogenic effects are not mediated by interaction with CMG2. This work represents the first reported high throughput screening assay targeting CMG2 to identify possible inhibitors of both angiogenesis and anthrax intoxication.
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Affiliation(s)
- Michael S. Rogers
- Department of Surgery, Vascular Biology Program, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lorna M. Cryan
- Department of Surgery, Vascular Biology Program, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Kaiane A. Habeshian
- Department of Surgery, Vascular Biology Program, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lauren Bazinet
- Department of Surgery, Vascular Biology Program, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Thomas P. Caldwell
- Department of Chemistry, Clemson University, Clemson, South Carolina, United States of America
| | - P. Christine Ackroyd
- Department of Chemistry, Clemson University, Clemson, South Carolina, United States of America
| | - Kenneth A. Christensen
- Department of Chemistry, Clemson University, Clemson, South Carolina, United States of America
- * E-mail:
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8
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The genomic basis for the evolution of a novel form of cellular reproduction in the bacterium Epulopiscium. BMC Genomics 2012; 13:265. [PMID: 22721417 PMCID: PMC3416734 DOI: 10.1186/1471-2164-13-265] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2011] [Accepted: 06/21/2012] [Indexed: 11/23/2022] Open
Abstract
Background Epulopiscium sp. type B, a large intestinal bacterial symbiont of the surgeonfish Naso tonganus, does not reproduce by binary fission. Instead, it forms multiple intracellular offspring using a process with morphological features similar to the survival strategy of endospore formation in other Firmicutes. We hypothesize that intracellular offspring formation in Epulopiscium evolved from endospore formation and these two developmental programs share molecular mechanisms that are responsible for the observed morphological similarities. Results To test this, we sequenced the genome of Epulopiscium sp. type B to draft quality. Comparative analysis with the complete genome of its close, endospore-forming relative, Cellulosilyticum lentocellum, identified homologs of well-known sporulation genes characterized in Bacillus subtilis. Of the 147 highly conserved B. subtilis sporulation genes used in this analysis, we found 57 homologs in the Epulopiscium genome and 87 homologs in the C. lentocellum genome. Conclusions Genes coding for components of the central regulatory network which govern the expression of forespore and mother-cell-specific sporulation genes and the machinery used for engulfment appear best conserved. Low conservation of genes expressed late in endospore formation, particularly those that confer resistance properties and encode germinant receptors, suggest that Epulopiscium has lost the ability to form a mature spore. Our findings provide a framework for understanding the evolution of a novel form of cellular reproduction.
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Current Status of Nonantibiotic and Adjunct Therapies for Clostridium difficile Infection. Curr Infect Dis Rep 2011; 13:21-7. [PMID: 21308451 DOI: 10.1007/s11908-010-0155-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Clostridium difficile infection (CDI) is a leading cause of nosocomial infections and the most important cause of health care-associated diarrhea worldwide. Standard treatment of CDI consists of modifying underlying antibiotic exposure, aggressive supportive measures, and therapy with specific antibiotics, most commonly metronidazole or vancomycin. This general approach to CDI has remained largely unchanged for decades. In an effort to improve outcomes and reduce recurrences of CDI, interest has been renewed in the development of nonantibiotic and adjunct approaches to therapy. In this review, we highlight some of these recent, resurrected, and novel nonantibiotic treatments.
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10
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Cooperativity and interference of germination pathways in Bacillus anthracis spores. J Bacteriol 2011; 193:4192-8. [PMID: 21685276 DOI: 10.1128/jb.05126-11] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Spore germination is the first step to Bacillus anthracis pathogenicity. Previous work has shown that B. anthracis spores use germination (Ger) receptors to recognize amino acids and nucleosides as germinants. Genetic analysis has putatively paired each individual Ger receptor with a specific germinant. However, Ger receptors seem to be able to partially compensate for each other and recognize alternative germinants. Using kinetic analysis of B. anthracis spores germinated with inosine and L-alanine, we previously determined kinetic parameters for this germination process and showed binding synergy between the cogerminants. In this work, we expanded our kinetic analysis to determine kinetic parameters and binding order for every B. anthracis spore germinant pair. Our results show that germinant binding can exhibit positive, neutral, or negative cooperativity. Furthermore, different germinants can bind spores by either a random or an ordered mechanism. Finally, simultaneous triggering of multiple germination pathways shows that germinants can either cooperate or interfere with each other during the spore germination process. We postulate that the complexity of germination responses may allow B. anthracis spores to respond to different environments by activating different germination pathways.
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11
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Testing nucleoside analogues as inhibitors of Bacillus anthracis spore germination in vitro and in macrophage cell culture. Antimicrob Agents Chemother 2010; 54:5329-36. [PMID: 20921305 DOI: 10.1128/aac.01029-10] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Bacillus anthracis, the etiological agent of anthrax, has a dormant stage in its life cycle known as the endospore. When conditions become favorable, spores germinate and transform into vegetative bacteria. In inhalational anthrax, the most fatal manifestation of the disease, spores enter the organism through the respiratory tract and germinate in phagosomes of alveolar macrophages. Germinated cells can then produce toxins and establish infection. Thus, germination is a crucial step for the initiation of pathogenesis. B. anthracis spore germination is activated by a wide variety of amino acids and purine nucleosides. Inosine and l-alanine are the two most potent nutrient germinants in vitro. Recent studies have shown that germination can be hindered by isomers or structural analogues of germinants. 6-Thioguanosine (6-TG), a guanosine analogue, is able to inhibit germination and prevent B. anthracis toxin-mediated necrosis in murine macrophages. In this study, we screened 46 different nucleoside analogues as activators or inhibitors of B. anthracis spore germination in vitro. These compounds were also tested for their ability to protect the macrophage cell line J774a.1 from B. anthracis cytotoxicity. Structure-activity relationship analysis of activators and inhibitors clarified the binding mechanisms of nucleosides to B. anthracis spores. In contrast, no structure-activity relationships were apparent for compounds that protected macrophages from B. anthracis-mediated killing. However, multiple inhibitors additively protected macrophages from B. anthracis.
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Mallozzi M, Viswanathan VK, Vedantam G. Spore-forming Bacilli and Clostridia in human disease. Future Microbiol 2010; 5:1109-23. [DOI: 10.2217/fmb.10.60] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Many Gram-positive spore-forming bacteria in the Firmicute phylum are important members of the human commensal microbiota, which, in rare cases, cause opportunistic infections. Other spore-formers, however, have evolved to become dedicated pathogens that can cause a striking variety of diseases. Despite variations in disease presentation, the etiologic agent is often the spore, with bacterially produced toxins playing a central role in the pathophysiology of infection. This review will focus on the specific diseases caused by spores of the Clostridia and Bacilli.
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Affiliation(s)
- Michael Mallozzi
- Department of Veterinary Science and Microbiology, University of Arizona, 1117, East Lowell St., Building 90, Room 303, Tucson, AZ 85721, USA
| | - VK Viswanathan
- Department of Veterinary Science and Microbiology, University of Arizona, 1117, East Lowell St., Building 90, Room 303, Tucson, AZ 85721, USA
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Cote CK, Bozue J, Twenhafel N, Welkos SL. Effects of altering the germination potential of Bacillus anthracis spores by exogenous means in a mouse model. J Med Microbiol 2009; 58:816-825. [DOI: 10.1099/jmm.0.008656-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Inhalational anthrax is the most severe form of anthrax. It has been shown in small-animal and non-human primate models that relatively large pools of ungerminated Bacillus anthracis spores can remain within the alveolar spaces for days to weeks post-inhalation or until transported to areas more favourable for germination and bacillary outgrowth. In this study, spores of the Ames strain that were exposed to germination-inducing media prior to intranasal delivery were significantly less infectious than spores delivered in either water or germination-inhibitory medium. The effect of manipulating the germination potential of these spores within the lungs of infected mice by exogenous germination-altering media was examined. The data suggested that neither inducing germination nor inhibiting germination of spores within the lungs protected mice from the ensuing infection. Germination-altering strategies could, instead, significantly increase the severity of disease in a mouse model of inhalational anthrax when implemented in vivo. It was shown that germination-altering strategies, in this study, were not beneficial to the infected host and are impractical as in vivo countermeasures.
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Affiliation(s)
- C. K. Cote
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD, USA
| | - J. Bozue
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD, USA
| | - N. Twenhafel
- Pathology Division, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD, USA
| | - S. L. Welkos
- Bacteriology Division, US Army Medical Research Institute of Infectious Diseases, 1425 Porter Street, Fort Detrick, Frederick, MD, USA
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14
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Antimicrobial effects of interferon-inducible CXC chemokines against Bacillus anthracis spores and bacilli. Infect Immun 2009; 77:1664-78. [PMID: 19179419 DOI: 10.1128/iai.01208-08] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Based on previous studies showing that host chemokines exert antimicrobial activities against bacteria, we sought to determine whether the interferon-inducible Glu-Leu-Arg-negative CXC chemokines CXCL9, CXCL10, and CXCL11 exhibit antimicrobial activities against Bacillus anthracis. In vitro analysis demonstrated that all three CXC chemokines exerted direct antimicrobial effects against B. anthracis spores and bacilli including marked reductions in spore and bacillus viability as determined using a fluorometric assay of bacterial viability and CFU determinations. Electron microscopy studies revealed that CXCL10-treated spores failed to undergo germination as judged by an absence of cytological changes in spore structure that occur during the process of germination. Immunogold labeling of CXCL10-treated spores demonstrated that the chemokine was located internal to the exosporium in association primarily with the spore coat and its interface with the cortex. To begin examining the potential biological relevance of chemokine-mediated antimicrobial activity, we used a murine model of inhalational anthrax. Upon spore challenge, the lungs of C57BL/6 mice (resistant to inhalational B. anthracis infection) had significantly higher levels of CXCL9, CXCL10, and CXCL11 than did the lungs of A/J mice (highly susceptible to infection). Increased CXC chemokine levels were associated with significantly reduced levels of spore germination within the lungs as determined by in vivo imaging. Taken together, our data demonstrate a novel antimicrobial role for host chemokines against B. anthracis that provides unique insight into host defense against inhalational anthrax; these data also support the notion for an innovative approach in treating B. anthracis infection as well as infections caused by other spore-forming organisms.
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15
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Wheeldon L, Worthington T, Hilton A, Elliott T, Lambert P. Physical and chemical factors influencing the germination ofClostridium difficilespores. J Appl Microbiol 2008; 105:2223-30. [DOI: 10.1111/j.1365-2672.2008.03965.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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16
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Rosch JW, Sublett J, Gao G, Wang YD, Tuomanen EI. Calcium efflux is essential for bacterial survival in the eukaryotic host. Mol Microbiol 2008; 70:435-44. [PMID: 18761687 DOI: 10.1111/j.1365-2958.2008.06425.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In dynamic environments, intracellular homeostasis is maintained by transport systems found in all cells. While bacterial influx systems for essential trace cations are known to contribute to pathogenesis, efflux systems have been characterized mainly in contaminated environmental sites. We describe that the high calcium concentrations in the normal human host were toxic to pneumococci and that bacterial survival in vivo depended on CaxP, the first Ca2+ exporter reported in bacteria. CaxP homologues were found in the eukaryotic sacroplasmic reticulum and in many bacterial genomes. A caxP- mutant accumulated intracellular calcium, a state that was used to reveal signalling networks responsive to changes in intracellular calcium concentration. Chemical inhibition of CaxP was bacteriostatic in physiological calcium concentrations, suggesting a new antibiotic target uncovered under conditions in the eukaryotic host.
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Affiliation(s)
- Jason W Rosch
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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