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Anumudu C, Hart A, Miri T, Onyeaka H. Recent Advances in the Application of the Antimicrobial Peptide Nisin in the Inactivation of Spore-Forming Bacteria in Foods. Molecules 2021; 26:5552. [PMID: 34577022 PMCID: PMC8469619 DOI: 10.3390/molecules26185552] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/01/2021] [Accepted: 09/09/2021] [Indexed: 11/16/2022] Open
Abstract
Conventional thermal and chemical treatments used in food preservation have come under scrutiny by consumers who demand minimally processed foods free from chemical agents but microbiologically safe. As a result, antimicrobial peptides (AMPs) such as bacteriocins and nisin that are ribosomally synthesised by bacteria, more prominently by the lactic acid bacteria (LAB) have appeared as a potent alternative due to their multiple biological activities. They represent a powerful strategy to prevent the development of spore-forming microorganisms in foods. Unlike thermal methods, they are natural without an adverse impact on food organoleptic and nutritional attributes. AMPs such as nisin and bacteriocins are generally effective in eliminating the vegetative forms of spore-forming bacteria compared to the more resilient spore forms. However, in combination with other non-thermal treatments, such as high pressure, supercritical carbon dioxide, electric pulses, a synergistic effect with AMPs such as nisin exists and has been proven to be effective in the inactivation of microbial spores through the disruption of the spore structure and prevention of spore outgrowth. The control of microbial spores in foods is essential in maintaining food safety and extension of shelf-life. Thus, exploration of the mechanisms of action of AMPs such as nisin is critical for their design and effective application in the food industry. This review harmonises information on the mechanisms of bacteria inactivation from published literature and the utilisation of AMPs in the control of microbial spores in food. It highlights future perspectives in research and application in food processing.
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Affiliation(s)
- Christian Anumudu
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (C.A.); (T.M.)
| | - Abarasi Hart
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK;
| | - Taghi Miri
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (C.A.); (T.M.)
| | - Helen Onyeaka
- School of Chemical Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (C.A.); (T.M.)
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What's new and notable in bacterial spore killing! World J Microbiol Biotechnol 2021; 37:144. [PMID: 34351499 PMCID: PMC8342367 DOI: 10.1007/s11274-021-03108-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Accepted: 07/05/2021] [Indexed: 02/08/2023]
Abstract
Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called “germinate to eradicate” strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable.
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Opportunities for Nanomedicine in Clostridioides difficile Infection. Antibiotics (Basel) 2021; 10:antibiotics10080948. [PMID: 34438998 PMCID: PMC8388953 DOI: 10.3390/antibiotics10080948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 12/19/2022] Open
Abstract
Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.
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Production and quality improvement of Indian cottage cheese (Paneer) using high pressure processing. INNOV FOOD SCI EMERG 2021. [DOI: 10.1016/j.ifset.2021.102746] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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Li J, Sun Y, Chen F, Hu X, Dong L. Pressure and Temperature Combined With Microbial Supernatant Effectively Inactivate Bacillus subtilis Spores. Front Microbiol 2021; 12:642501. [PMID: 34093462 PMCID: PMC8169991 DOI: 10.3389/fmicb.2021.642501] [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] [Received: 12/16/2020] [Accepted: 03/22/2021] [Indexed: 11/13/2022] Open
Abstract
Spores from the Bacillus species pose a challenge to the food industry because of their ubiquitous nature and extreme resistance. Accumulated evidence indicates that it is effective to induce spore germination homogenously before killing them. However, it is difficult to obtain and apply exogenous germination factors, which will affect food composition. Therefore, this study screened endogenous germinants from microorganisms by assessing the effect of Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae, Lactiplantibacillus plantarum, and Streptococcus thermophilus cultures (cell-free) on B. subtilis spore germination. The results showed that the supernatants from these five microorganisms induced spore germination instead of sediments. Moreover, the supernatants of E. coli, B. subtilis, and S. cerevisiae exhibited higher germination rates than L. plantarum and S. thermophilus, and the induction effects were concentration-dependent. Furthermore, plate counting confirmed that the microbial supernatants induced the lowest spore germination ratio on strains B. subtilis FB85 [germination receptors (GRs) mutant] but not strains B. subtilis PB705 (PrkC mutant). In addition, B. subtilis and S. cerevisiae supernatants, combined with pressure and temperature, were effective in spore inactivation. The findings suggested that microbial supernatants may include agents that induce spore germination and may be used for spore inactivation.
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Affiliation(s)
- Jingyu Li
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing, China
| | - Yaxin Sun
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing, China
| | - Fang Chen
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing, China
| | - Xiaosong Hu
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing, China
| | - Li Dong
- College of Food Science and Nutritional Engineering, National Engineering Research Center for Fruit and Vegetable Processing, Key Laboratory of Fruits and Vegetables Processing, Ministry of Agriculture, Engineering Research Centre for Fruits and Vegetables Processing, Ministry of Education, China Agricultural University, Beijing, China
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Hassan H, St-Gelais D, Gomaa A, Fliss I. Impact of Nisin and Nisin-Producing Lactococcus lactis ssp. lactis on Clostridium tyrobutyricum and Bacterial Ecosystem of Cheese Matrices. Foods 2021; 10:898. [PMID: 33921812 PMCID: PMC8073774 DOI: 10.3390/foods10040898] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/12/2021] [Accepted: 04/15/2021] [Indexed: 11/30/2022] Open
Abstract
Clostridium tyrobutyricum spores survive milk pasteurization and cause late blowing of cheeses and significant economic loss. The effectiveness of nisin-producing Lactococcus lactis ssp. lactis 32 as a protective strain for control the C. tyrobutyricum growth in Cheddar cheese slurry was compared to that of encapsulated nisin-A. The encapsulated nisin was more effective, with 1.0 log10 reductions of viable spores after one week at 30 °C and 4 °C. Spores were not detected for three weeks at 4 °C in cheese slurry made with 1.3% salt, or during week 2 with 2% salt. Gas production was observed after one week at 30 °C only in the control slurry made with 1.3% salt. In slurry made with the protective strain, the reduction in C. tyrobutyricum count was 0.6 log10 in the second week at 4 °C with both salt concentration. At 4 °C, nisin production started in week 2 and reached 97 µg/g after four weeks. Metabarcoding analysis targeting the sequencing of 16S rRNA revealed that the genus Lactococcus dominated for four weeks at 4 °C. In cheese slurry made with 2% salt, the relative abundance of the genus Clostridium decreased significantly in the presence of nisin or the protective strain. The results indicated that both strategies are able to control the growth of Clostridium development in Cheddar cheese slurries.
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Affiliation(s)
- Hebatoallah Hassan
- STELA Dairy Research Center, Institute of Nutrition and Functional Foods, Université Laval, Québec, QC G1V 0A6, Canada;
- Institute of Graduate Studies and Research, Alexandria University, Alexandria 21526, Egypt
| | - Daniel St-Gelais
- Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, QC J2S 8E3, Canada;
| | - Ahmed Gomaa
- National Research Center, Nutrition and Food Science Department, Cairo 12622, Egypt;
| | - Ismail Fliss
- STELA Dairy Research Center, Institute of Nutrition and Functional Foods, Université Laval, Québec, QC G1V 0A6, Canada;
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Aldrete-Tapia JA, Torres JA. Enhancing the Inactivation of Bacterial Spores during Pressure-Assisted Thermal Processing. FOOD ENGINEERING REVIEWS 2020. [DOI: 10.1007/s12393-020-09252-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Castro-Córdova P, Díaz-Yáñez F, Muñoz-Miralles J, Gil F, Paredes-Sabja D. Effect of antibiotic to induce Clostridioides difficile-susceptibility and infectious strain in a mouse model of Clostridioides difficile infection and recurrence. Anaerobe 2020; 62:102149. [PMID: 31940467 DOI: 10.1016/j.anaerobe.2020.102149] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 12/16/2019] [Accepted: 01/09/2020] [Indexed: 02/08/2023]
Abstract
The anaerobic bacterium Clostridioides difficile is the leading cause of antibiotic-associated diarrhea that can culminate in life-threating colitis. During the C. difficile infection (CDI), C. difficile produces toxins that generate the clinical symptoms of the disease, and produce spores, which persist in the host during antibiotic treatment and can cause recurrent CDI (R-CDI). In this work, we aimed to compare three antibiotic regimens in the susceptibility of mice to CDI and R-CDI (i.e., antibiotic cocktail followed by clindamycin, 5 days of cefoperazone and 10 days of cefoperazone) with three different C. difficile isolates (i.e., strains 630; R20291, and VPI 10463). We observed that the severity of the clinical symptoms of CDI and R-CDI was dependent on the antibiotic treatment used to induce C. difficile-susceptibility, and that the three strains generated a different onset to diarrhea and weight loss in mice that were administrated with the same antibiotic treatment and which differed in comparison to the effect previously reported by other research groups. Our results suggest that, in our experimental conditions, in those animals treated with antibiotic cocktail followed by clindamycin, infection with strain R20291 had the highest diarrhea manifestation in comparison to strains 630 and VPI 10463. In animals treated with cefoperazone for 5 days, infection with strains R20291 or 630 had the highest diarrhea manifestation in comparison to VPI 10463, while in animals treated with cefoperazone for 10 days, infection with strain R20291 or VPI 10463, but not 630, had the highest diarrhea manifestation.
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Affiliation(s)
- Pablo Castro-Córdova
- Millennium Nucleus in the Biology of Intestinal Microbiota, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile; Microbiota-Host Interactions & Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Fernando Díaz-Yáñez
- Millennium Nucleus in the Biology of Intestinal Microbiota, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile; Microbiota-Host Interactions & Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Juan Muñoz-Miralles
- Microbiota-Host Interactions & Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Fernando Gil
- Millennium Nucleus in the Biology of Intestinal Microbiota, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile; Microbiota-Host Interactions & Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile
| | - Daniel Paredes-Sabja
- Millennium Nucleus in the Biology of Intestinal Microbiota, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile; Microbiota-Host Interactions & Clostridia Research Group, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago, Chile.
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Shen A. Clostridioides difficile Spores: Bile Acid Sensors and Trojan Horses of Transmission. Clin Colon Rectal Surg 2020; 33:58-66. [PMID: 32104157 DOI: 10.1055/s-0040-1701230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Gram-positive, spore-forming bacterium, Clostridioides difficile is the leading cause of healthcare-associated infections in the United States, although it also causes a significant number of community-acquired infections. C. difficile infections, which range in severity from mild diarrhea to toxic megacolon, cost more to treat than matched infections, with an annual treatment cost of approximately $6 billion for almost half-a-million infections. These high-treatment costs are due to the high rates of C. difficile disease recurrence (>20%) and necessity for special disinfection measures. These complications arise in part because C. difficile makes metabolically dormant spores, which are the major infectious particle of this obligate anaerobe. These seemingly inanimate life forms are inert to antibiotics, resistant to commonly used disinfectants, readily disseminated, and capable of surviving in the environment for a long period of time. However, upon sensing specific bile salts in the vertebrate gut, C. difficile spores transform back into the vegetative cells that are responsible for causing disease. This review discusses how spores are ideal vectors for disease transmission and how antibiotics modulate this process. We also describe the resistance properties of spores and how they create challenges eradicating spores, as well as promote their spread. Lastly, environmental reservoirs of C. difficile spores and strategies for destroying them particularly in health care environments will be discussed.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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10
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Pickering DS, Vernon JJ, Freeman J, Wilcox MH, Chilton CH. Investigating the transient and persistent effects of heat on Clostridium difficile spores. J Med Microbiol 2019; 68:1445-1454. [PMID: 31429817 DOI: 10.1099/jmm.0.001048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Purpose. Clostridium difficile spores are extremely resilient to high temperatures. Sublethal temperatures are associated with the 'reactivation' of dormant spores, and are utilized to maximize C. difficile spore recovery. Spore eradication is of vital importance to the food industry. The current study seeks to elucidate the transient and persisting effects of heating C. difficile spores at various temperatures.Methods. Spores of five C. difficile strains of different ribotypes (001, 015, 020, 027 and 078) were heated at 50, 60 and 70-80 °C for 60 min in phosphate-buffered saline (PBS) and enumerated at 0, 15, 30, 45 and 60 min. GInaFiT was used to model the kinetics of spore inactivation. In subsequent experiments, spores were transferred to enriched brain heart infusion (BHI) broths after 10 min of 80 °C heat treatment in PBS; samples were enumerated at 90 min and 24 h.Results. The spores of all strains demonstrated log-linear inactivation with tailing when heated for 60 min at 80 °C [(x̄=7.54±0.04 log10 vs 4.72±0.09 log10 colony-forming units (c.f.u.) ml- 1; P<0.001]. At 70 °C, all strains except 078 exhibited substantial decline in recovery over 60 min. Interestingly, 50 °C heat treatment had an inhibitory effect on 078 spore recovery at 0 vs 60 min (7.61±0.06 log10 c.f.u. ml- 1 vs 6.13±0.05 log10 c.f.u. ml- 1; P<0.001). Heating at 70/80 °C inhibited the initial germination and outgrowth of both newly produced and aged spores in enriched broths. This inhibition appeared to be transient; after 24 h vegetative counts were higher in heat-treated vs non-heat-treated spores (x̄=7.65±0.04 log10 c.f.u. ml- 1 vs 6.79±0.06 log10 c.f.u. ml- 1; P<0.001).Conclusions. The 078 spores were more resistant to the inhibitory effects of higher temperatures. Heat initially inhibits spore germination, but the subsequent outgrowth of vegetative populations accelerates after the initial inhibitory period.
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Affiliation(s)
- D S Pickering
- Healthcare Associated Infections Research Group, Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, West Yorkshire, UK
| | - J J Vernon
- Healthcare Associated Infections Research Group, Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, West Yorkshire, UK
| | - J Freeman
- Microbiology, Leeds Teaching Hospitals Trust, Leeds, UK
| | - M H Wilcox
- Microbiology, Leeds Teaching Hospitals Trust, Leeds, UK.,Healthcare Associated Infections Research Group, Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, West Yorkshire, UK
| | - C H Chilton
- Healthcare Associated Infections Research Group, Leeds Institute for Biomedical and Clinical Sciences, University of Leeds, West Yorkshire, UK
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12
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Spore Production of Toxigenic and Non-toxigenic Clostridium difficile Isolates in Sub-MIC of Vancomycin, Clindamycin, and Ceftazidime. Jundishapur J Microbiol 2019. [DOI: 10.5812/jjm.57905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Zhang Y, Mathys A. Superdormant Spores as a Hurdle for Gentle Germination-Inactivation Based Spore Control Strategies. Front Microbiol 2019; 9:3163. [PMID: 30662433 PMCID: PMC6328458 DOI: 10.3389/fmicb.2018.03163] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 12/06/2018] [Indexed: 02/04/2023] Open
Abstract
Bacterial spore control strategies based on the germination-inactivation principle can lower the thermal load needed to inactivate bacterial spores and thus preserve food quality better. However, the success of this strategy highly depends on the germination of spores, and a subpopulation of spores that fail to germinate or germinate extremely slowly hinders the application of this strategy. This subpopulation of spores is termed 'superdormant (SD) spores.' Depending on the source of the germination stimulus, SD spores are categorized as nutrient-SD spores, Ca2+-dipicolinic acid SD spores, dodecylamine-SD spores, and high pressure SD spores. In recent decades, research has been done to isolate these different groups of SD spores and unravel the cause of their germination deficiency as well as their germination capacities. This review summarizes the challenges caused by SD spores, their isolation and characterization, the underlying mechanisms of their germination deficiency, and the future research directions needed to tackle this topic in further depth.
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Affiliation(s)
| | - Alexander Mathys
- Sustainable Food Processing Laboratory, Institute of Food, Nutrition and Health, Department of Health Science and Technology, ETH Zurich, Zurich, Switzerland
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Zhu D, Sorg JA, Sun X. Clostridioides difficile Biology: Sporulation, Germination, and Corresponding Therapies for C. difficile Infection. Front Cell Infect Microbiol 2018; 8:29. [PMID: 29473021 PMCID: PMC5809512 DOI: 10.3389/fcimb.2018.00029] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/23/2018] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is a Gram-positive, spore-forming, toxin-producing anaerobe, and an important nosocomial pathogen. Due to the strictly anaerobic nature of the vegetative form, spores are the main morphotype of infection and transmission of the disease. Spore formation and their subsequent germination play critical roles in C. difficile infection (CDI) progress. Under suitable conditions, C. difficile spores will germinate and outgrow to produce the pathogenic vegetative form. During CDI, C. difficile produces toxins (TcdA and TcdB) that are required to initiate the disease. Meanwhile, it also produces spores that are responsible for the persistence and recurrence of C. difficile in patients. Recent studies have shed light on the regulatory mechanisms of C. difficile sporulation and germination. This review is to summarize recent advances on the regulation of sporulation/germination in C. difficile and the corresponding therapeutic strategies that are aimed at these important processes.
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Affiliation(s)
- Duolong Zhu
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
| | - Joseph A Sorg
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Xingmin Sun
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, United States
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15
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Roshan N, Hammer KA, Riley TV. Non-conventional antimicrobial and alternative therapies for the treatment of Clostridium difficile infection. Anaerobe 2018; 49:103-111. [DOI: 10.1016/j.anaerobe.2018.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/19/2017] [Accepted: 01/05/2018] [Indexed: 02/08/2023]
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16
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Chai C, Lee KS, Imm GS, Kim YS, Oh SW. Inactivation of Clostridium difficile spore outgrowth by synergistic effects of nisin and lysozyme. Can J Microbiol 2017; 63:638-643. [PMID: 28346844 DOI: 10.1139/cjm-2016-0550] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inactivating Clostridium difficile spores is difficult, as they are resistant to heat, chemicals, and antimicrobials. However, this note describes inactivation of C. difficile spore outgrowth by incubation in a solution containing a germinant (1% (m/v) sodium taurocholate), co-germinants (1% (m/v) tryptose and 1% (m/v) NaCl), and natural antimicrobials (20 nmol·L-1 nisin and 0.2 mmol·L-1 lysozyme). Clostridium difficile spores were resistant to nisin and lysozyme but became susceptible during germination and outgrowth triggered and promoted by sodium taurocholate, tryptose, and NaCl. The degree of inactivation of germinated and outgrowing C. difficile spores by both nisin and lysozyme was greater than the sum of that by nisin and lysozyme individually, suggesting synergistic inactivation of C. difficile spores. The germinant, co-germinants, and natural antimicrobials used in this study are safe for human contact and consumption. Therefore, these findings will facilitate the development of a safe and effective method to inactivate C. difficile spore.
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Affiliation(s)
- Changhoon Chai
- a Division of Applied Animal Science, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Kyung-Soo Lee
- b Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea
| | - Goo-Sang Imm
- b Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea
| | - Young Soon Kim
- c Department of Food and Nutrition, Korea University, Seoul 02841, Republic of Korea
| | - Se-Wook Oh
- b Department of Food and Nutrition, Kookmin University, Seoul 02707, Republic of Korea
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Talukdar PK, Udompijitkul P, Hossain A, Sarker MR. Inactivation Strategies for Clostridium perfringens Spores and Vegetative Cells. Appl Environ Microbiol 2017; 83:e02731-16. [PMID: 27795314 PMCID: PMC5165105 DOI: 10.1128/aem.02731-16] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Clostridium perfringens is an important pathogen to human and animals and causes a wide array of diseases, including histotoxic and gastrointestinal illnesses. C. perfringens spores are crucial in terms of the pathogenicity of this bacterium because they can survive in a dormant state in the environment and return to being live bacteria when they come in contact with nutrients in food or the human body. Although the strategies to inactivate C. perfringens vegetative cells are effective, the inactivation of C. perfringens spores is still a great challenge. A number of studies have been conducted in the past decade or so toward developing efficient inactivation strategies for C. perfringens spores and vegetative cells, which include physical approaches and the use of chemical preservatives and naturally derived antimicrobial agents. In this review, different inactivation strategies applied to control C. perfringens cells and spores are summarized, and the potential limitations and challenges of these strategies are discussed.
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Affiliation(s)
- Prabhat K Talukdar
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
- Department of Microbiology, College of Science, Oregon State University, Corvallis, Oregon, USA
| | - Pathima Udompijitkul
- Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Bangkok, Thailand
| | - Ashfaque Hossain
- Department of Medical Microbiology and Immunology, Ras Al Khaimah Medical and Health Sciences University, Ras Al Khaimah, United Arab Emirates
| | - Mahfuzur R Sarker
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, Oregon, USA
- Department of Microbiology, College of Science, Oregon State University, Corvallis, Oregon, USA
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Krawczyk AO, Berendsen EM, de Jong A, Boekhorst J, Wells-Bennik MHJ, Kuipers OP, Eijlander RT. A transposon present in specific strains ofBacillus subtilisnegatively affects nutrient- and dodecylamine-induced spore germination. Environ Microbiol 2016; 18:4830-4846. [DOI: 10.1111/1462-2920.13386] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 05/20/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Antonina O. Krawczyk
- Laboratory of Molecular Genetics; University of Groningen; Nijenborgh 7 9747 AG Groningen the Netherlands
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
| | - Erwin M. Berendsen
- Laboratory of Molecular Genetics; University of Groningen; Nijenborgh 7 9747 AG Groningen the Netherlands
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
- NIZO Food Research B.V; Kernhemseweg 2 6718 ZB Ede the Netherlands
| | - Anne de Jong
- Laboratory of Molecular Genetics; University of Groningen; Nijenborgh 7 9747 AG Groningen the Netherlands
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
| | - Jos Boekhorst
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
- NIZO Food Research B.V; Kernhemseweg 2 6718 ZB Ede the Netherlands
| | - Marjon H. J. Wells-Bennik
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
- NIZO Food Research B.V; Kernhemseweg 2 6718 ZB Ede the Netherlands
| | - Oscar P. Kuipers
- Laboratory of Molecular Genetics; University of Groningen; Nijenborgh 7 9747 AG Groningen the Netherlands
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
| | - Robyn T. Eijlander
- Laboratory of Molecular Genetics; University of Groningen; Nijenborgh 7 9747 AG Groningen the Netherlands
- Top Institute Food and Nutrition (TIFN); Nieuwe Kanaal 9A 6709 PA Wageningen the Netherlands
- NIZO Food Research B.V; Kernhemseweg 2 6718 ZB Ede the Netherlands
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Egan K, Field D, Rea MC, Ross RP, Hill C, Cotter PD. Bacteriocins: Novel Solutions to Age Old Spore-Related Problems? Front Microbiol 2016; 7:461. [PMID: 27092121 PMCID: PMC4824776 DOI: 10.3389/fmicb.2016.00461] [Citation(s) in RCA: 72] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 03/21/2016] [Indexed: 02/01/2023] Open
Abstract
Bacteriocins are ribosomally synthesized antimicrobial peptides produced by bacteria, which have the ability to kill or inhibit other bacteria. Many bacteriocins are produced by food grade lactic acid bacteria (LAB). Indeed, the prototypic bacteriocin, nisin, is produced by Lactococcus lactis, and is licensed in over 50 countries. With consumers becoming more concerned about the levels of chemical preservatives present in food, bacteriocins offer an alternative, more natural approach, while ensuring both food safety and product shelf life. Bacteriocins also show additive/synergistic effects when used in combination with other treatments, such as heating, high pressure, organic compounds, and as part of food packaging. These features are particularly attractive from the perspective of controlling sporeforming bacteria. Bacterial spores are common contaminants of food products, and their outgrowth may cause food spoilage or food-borne illness. They are of particular concern to the food industry due to their thermal and chemical resistance in their dormant state. However, when spores germinate they lose the majority of their resistance traits, making them susceptible to a variety of food processing treatments. Bacteriocins represent one potential treatment as they may inhibit spores in the post-germination/outgrowth phase of the spore cycle. Spore eradication and control in food is critical, as they are able to spoil and in certain cases compromise the safety of food by producing dangerous toxins. Thus, understanding the mechanisms by which bacteriocins exert their sporostatic/sporicidal activity against bacterial spores will ultimately facilitate their optimal use in food. This review will focus on the use of bacteriocins alone, or in combination with other innovative processing methods to control spores in food, the current knowledge and gaps therein with regard to bacteriocin-spore interactions and discuss future research approaches to enable spores to be more effectively targeted by bacteriocins in food settings.
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Affiliation(s)
- Kevin Egan
- School of Microbiology, University College Cork Cork, Ireland
| | - Des Field
- School of Microbiology, University College Cork Cork, Ireland
| | - Mary C Rea
- Teagasc Food Research Centre, MooreparkFermoy, Ireland; APC Microbiome InstituteUniversity College Cork, Ireland
| | - R Paul Ross
- APC Microbiome InstituteUniversity College Cork, Ireland; College of Science, Engineering and Food Science, University College CorkCork, Ireland
| | - Colin Hill
- School of Microbiology, University College CorkCork, Ireland; APC Microbiome InstituteUniversity College Cork, Ireland
| | - Paul D Cotter
- Teagasc Food Research Centre, MooreparkFermoy, Ireland; APC Microbiome InstituteUniversity College Cork, Ireland
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Uptake and levels of the antibiotic berberine in individual dormant and germinatingClostridium difficileandBacillus cereusspores as measured by laser tweezers Raman spectroscopy. J Antimicrob Chemother 2016; 71:1540-6. [DOI: 10.1093/jac/dkv504] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 12/29/2015] [Indexed: 12/19/2022] Open
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Lay CL, Dridi L, Bergeron MG, Ouellette M, Fliss I. Nisin is an effective inhibitor of Clostridium difficile vegetative cells and spore germination. J Med Microbiol 2016; 65:169-175. [DOI: 10.1099/jmm.0.000202] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Affiliation(s)
- Christophe Le Lay
- STELA Dairy Research Centre, Institute of Nutrition and Functional Foods, Université Laval, Québec City, QC, Canada
- Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, QC, Canada
- Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec City, QC, Canada
| | - Larbi Dridi
- Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, QC, Canada
- Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec City, QC, Canada
| | - Michel G. Bergeron
- Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, QC, Canada
- Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec City, QC, Canada
| | - Marc Ouellette
- Centre de recherche en infectiologie de l'Université Laval, Axe Maladies infectieuses et immunitaires, Centre de recherche du CHU de Québec, Québec City, QC, Canada
- Département de microbiologie-infectiologie et d'immunologie, Faculté de médecine, Université Laval, Québec City, QC, Canada
| | - Ismaı¨l Fliss
- STELA Dairy Research Centre, Institute of Nutrition and Functional Foods, Université Laval, Québec City, QC, Canada
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Effect of Variation in Test Methods on Performance of Ultraviolet-C Radiation Room Decontamination. Infect Control Hosp Epidemiol 2016; 37:555-60. [DOI: 10.1017/ice.2015.349] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVETo determine the effect of variation in test methods on performance of an ultraviolet-C (UV-C) room decontamination device.DESIGNLaboratory evaluation.METHODSWe compared the efficacy of 2 UV-C room decontamination devices with low pressure mercury gas bulbs. For 1 of the devices, we evaluated the effect of variation in spreading of the inoculum, carrier orientation relative to the device, type of organic load, type of carrier, height of carrier, and uninterrupted versus interrupted exposures on measured UV-C killing of methicillin-resistant Staphylococcus aureus and Clostridium difficile spores.RESULTSThe 2 UV-C room decontamination devices achieved similar log10 colony-forming unit reductions in the pathogens with exposure times ranging from 5 to 40 minutes. On steel carriers, spreading of the inoculum over a larger surface area significantly enhanced killing of both pathogens, such that a 10-minute exposure on a 22-mm2 disk resulted in greater than 2 log reduction in C. difficile spores. Orientation of carriers in parallel rather than perpendicular with the UV-C lamps significantly enhanced killing of both pathogens. Different types of organic load also significantly affected measured organism reductions, whereas type of carrier, variation in carrier height, and interrupted exposure cycles did not.CONCLUSIONSVariation in test methods can significantly impact measured reductions in pathogens by UV-C devices during experimental testing. Our findings highlight the need for standardized laboratory methods for testing the efficacy of UV-C devices and for evaluations of the efficacy of short UV-C exposure times in real-world settings.Infect Control Hosp Epidemiol 2016;37:555–560
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Xu C, Salsali H, Weese S, Warriner K. Inactivation of Clostridium difficile in sewage sludge by anaerobic thermophilic digestion. Can J Microbiol 2015; 62:16-23. [PMID: 26564276 DOI: 10.1139/cjm-2015-0511] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There has been an increase in community-associated Clostridium difficile infections with biosolids derived from wastewater treatment being identified as one potential source. The current study evaluated the efficacy of thermophilic digestion in decreasing levels of C. difficile ribotype 078 associated with sewage sludge. Five isolates of C. difficile 078 were introduced (final density of 5 log CFU/g) into digested sludge and subjected to anaerobic digestion at mesophilic (36 or 42 °C) or thermophilic (55 °C) temperatures for up to 60 days. It was found that mesophilic digestion at 36 °C did not result in a significant reduction in C. difficile spore levels. In contrast, thermophilic sludge digestion reduced endospore levels at a rate of 0.19-2.68 log CFU/day, depending on the strain tested. The mechanism of lethality was indirect - by stimulating germination then inactivating the resultant vegetative cells. Acidification of sludge by adding acetic acid (6 g/L) inhibited the germination of spores regardless of the sludge digestion temperature. In conclusion, thermophilic digestion can be applied to reduce C. difficile in biosolids, thereby reducing the environmental burden of the enteric pathogen.
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Affiliation(s)
- Changyun Xu
- a Department of Food Science, University of Guelph, ON N1G 2W1, Canada
| | | | - Scott Weese
- c Department of Pathobiology, Ontario Veterinary College, University of Guelph, ON N1G 2W1, Canada
| | - Keith Warriner
- a Department of Food Science, University of Guelph, ON N1G 2W1, Canada
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Jarrad A, Karoli T, Blaskovich MAT, Lyras D, Cooper MA. Clostridium difficile drug pipeline: challenges in discovery and development of new agents. J Med Chem 2015; 58:5164-85. [PMID: 25760275 PMCID: PMC4500462 DOI: 10.1021/jm5016846] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Indexed: 12/17/2022]
Abstract
In the past decade Clostridium difficile has become a bacterial pathogen of global significance. Epidemic strains have spread throughout hospitals, while community acquired infections and other sources ensure a constant inoculation of spores into hospitals. In response to the increasing medical burden, a new C. difficile antibiotic, fidaxomicin, was approved in 2011 for the treatment of C. difficile-associated diarrhea. Rudimentary fecal transplants are also being trialed as effective treatments. Despite these advances, therapies that are more effective against C. difficile spores and less damaging to the resident gastrointestinal microbiome and that reduce recurrent disease are still desperately needed. However, bringing a new treatment for C. difficile infection to market involves particular challenges. This review covers the current drug discovery pipeline, including both small molecule and biologic therapies, and highlights the challenges associated with in vitro and in vivo models of C. difficile infection for drug screening and lead optimization.
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Affiliation(s)
- Angie
M. Jarrad
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Tomislav Karoli
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Mark A. T. Blaskovich
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
| | - Dena Lyras
- School
of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia
| | - Matthew A. Cooper
- The
Institute for Molecular Bioscience, University
of Queensland, St. Lucia, Queensland 4072, Australia
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Characterization of the Dynamic Germination of Individual Clostridium difficile Spores Using Raman Spectroscopy and Differential Interference Contrast Microscopy. J Bacteriol 2015; 197:2361-73. [PMID: 25939833 DOI: 10.1128/jb.00200-15] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Accepted: 04/27/2015] [Indexed: 12/18/2022] Open
Abstract
UNLABELLED The Gram-positive spore-forming anaerobe Clostridium difficile is a leading cause of nosocomial diarrhea. Spores of C. difficile initiate infection when triggered to germinate by bile salts in the gastrointestinal tract. We analyzed germination kinetics of individual C. difficile spores using Raman spectroscopy and differential interference contrast (DIC) microscopy. Similar to Bacillus spores, individual C. difficile spores germinating with taurocholate plus glycine began slow leakage of a ∼15% concentration of a chelate of Ca(2+) and dipicolinic acid (CaDPA) at a heterogeneous time T1, rapidly released CaDPA at Tlag, completed CaDPA release at Trelease, and finished peptidoglycan cortex hydrolysis at Tlysis. T1 and Tlag values for individual spores were heterogeneous, but ΔTrelease periods (Trelease - Tlag) were relatively constant. In contrast to Bacillus spores, heat treatment did not stimulate spore germination in the two C. difficile strains tested. C. difficile spores did not germinate with taurocholate or glycine alone, and different bile salts differentially promoted spore germination, with taurocholate and taurodeoxycholate being best. Transient exposure of spores to taurocholate plus glycine was sufficient to commit individual spores to germinate. C. difficile spores did not germinate with CaDPA, in contrast to B. subtilis and C. perfringens spores. However, the detergent dodecylamine induced C. difficile spore germination, and rates were increased by spore coat removal although cortex hydrolysis did not follow Trelease, in contrast with B. subtilis. C. difficile spores lacking the cortex-lytic enzyme, SleC, germinated extremely poorly, and cortex hydrolysis was not observed in the few sleC spores that partially germinated. Overall, these findings indicate that C. difficile and B. subtilis spore germination exhibit key differences. IMPORTANCE Spores of the Gram-positive anaerobe Clostridium difficile are responsible for initiating infection by this important nosocomial pathogen. When exposed to germinants such as bile salts, C. difficile spores return to life through germination in the gastrointestinal tract and cause disease, but their germination has been studied only with population-wide measurements. In this work we used Raman spectroscopy and DIC microscopy to monitor the kinetics of germination of individual C. difficile spores, the commitment of spores to germination, and the effect of germinant type and concentration, sublethal heat shock, and spore decoating on germination. Our data suggest that the order of germination events in C. difficile spores differs from that in Bacillus spores and provide new insights into C. difficile spore germination.
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Geobacillus stearothermophilus ATCC 7953 spore chemical germination mechanisms in model systems. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.08.044] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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The effects of heat activation on Bacillus spore germination, with nutrients or under high pressure, with or without various germination proteins. Appl Environ Microbiol 2015; 81:2927-38. [PMID: 25681191 DOI: 10.1128/aem.00193-15] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Nutrient germination of spores of Bacillus species occurs through germinant receptors (GRs) in spores' inner membrane (IM) in a process stimulated by sublethal heat activation. Bacillus subtilis spores maximum germination rates via different GRs required different 75 °C heat activation times: 15 min for l-valine germination via the GerA GR and 4 h for germination with the L-asparagine-glucose-fructose-K(+) mixture via the GerB and GerK GRs, with GerK requiring the most heat activation. In some cases, optimal heat activation decreased nutrient concentrations for half-maximal germination rates. Germination of spores via various GRs by high pressure (HP) of 150 MPa exhibited heat activation requirements similar to those of nutrient germination, and the loss of the GerD protein, required for optimal GR function, did not eliminate heat activation requirements for maximal germination rates. These results are consistent with heat activation acting primarily on GRs. However, (i) heat activation had no effects on GR or GerD protein conformation, as probed by biotinylation by an external reagent; (ii) spores prepared at low and high temperatures that affect spores' IM properties exhibited large differences in heat activation requirements for nutrient germination; and (iii) spore germination by 550 MPa of HP was also affected by heat activation, but the effects were relatively GR independent. The last results are consistent with heat activation affecting spores' IM and only indirectly affecting GRs. The 150- and 550-MPa HP germinations of Bacillus amyloliquefaciens spores, a potential surrogate for Clostridium botulinum spores in HP treatments of foods, were also stimulated by heat activation.
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Barra-Carrasco J, Paredes-Sabja D. Clostridium difficile spores: a major threat to the hospital environment. Future Microbiol 2014; 9:475-86. [PMID: 24810347 DOI: 10.2217/fmb.14.2] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Clostridium difficile is a Gram-positive, anaerobic spore former and is an important nosocomial and community-acquired pathogenic bacterium. C. difficile infections (CDI) are a leading cause of infections worldwide with elevated rates of morbidity. Despite the fact that two major virulence factors, the enterotoxin TcdA and the cytotoxin TcdB, are essential in the development of CDI, C. difficile spores are the main vehicle of infection, and persistence and transmission of CDI and are thought to play an essential role in episodes of CDI recurrence and horizontal transmission. Recent research has unmasked several properties of C. difficile's unique strategy to form highly transmissible spores and to persist in the colonic environment. Therefore, the aim of this article is to summarize recent advances in the biological properties of C. difficile spores, which might be clinically relevant to improve the management of CDI in hospital environments.
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Affiliation(s)
- Jonathan Barra-Carrasco
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, República 217, Santiago, Chile
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Olguín-Araneda V, Banawas S, Sarker MR, Paredes-Sabja D. Recent advances in germination of Clostridium spores. Res Microbiol 2014; 166:236-43. [PMID: 25132133 DOI: 10.1016/j.resmic.2014.07.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/30/2014] [Accepted: 07/31/2014] [Indexed: 12/23/2022]
Abstract
Members of Clostridium genus are a diverse group of anaerobic spore-formers that includes several pathogenic species. Their anaerobic requirement enhances the importance of the dormant spore morphotype during infection, persistence and transmission. Bacterial spores are metabolically inactive and may survive for long times in the environment and germinate in presence of nutrients termed germinants. Recent progress with spores of several Clostridium species has identified the germinant receptors (GRs) involved in nutrient germinant recognition and initiation of spore germination. Signal transduction from GRs to the downstream effectors remains poorly understood but involves the release of dipicolinic acid. Two mechanistically different cortex hydrolytic machineries are present in Clostridium spores. Recent studies have also shed light into novel biological events that occur during spore formation (accumulation of transcriptional units) and transcription during early spore outgrowth. In summary, this review will cover all of the recent advances in Clostridium spore germination.
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Affiliation(s)
- Valeria Olguín-Araneda
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile
| | - Saeed Banawas
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, USA; Medical Laboratories Department, College of Science Al-Zulfi, Majmaah University, Saudi Arabia
| | - Mahfuzur R Sarker
- Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA; Department of Microbiology, College of Science, Oregon State University, Corvallis, OR, USA
| | - Daniel Paredes-Sabja
- Laboratorio de Mecanismos de Patogénesis Bacteriana, Departamento de Ciencias Biológicas, Facultad de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile; Department of Biomedical Sciences, College of Veterinary Medicine, Corvallis, OR, USA.
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Sensitive and selective culture medium for detection of environmental Clostridium difficile isolates without requirement for anaerobic culture conditions. J Clin Microbiol 2014; 52:3259-63. [PMID: 24958803 DOI: 10.1128/jcm.00793-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Effective and easy-to-use methods for detecting Clostridium difficile spore contamination would be useful for identifying environmental reservoirs and monitoring the effectiveness of room disinfection. Culture-based detection methods are sensitive for detecting C. difficile, but their utility is limited due to the requirement of anaerobic culture conditions and microbiological expertise. We developed a low-cost selective broth medium containing thioglycolic acid and l-cystine, termed C. difficile brucella broth with thioglycolic acid and l-cystine (CDBB-TC), for the detection of C. difficile from environmental specimens under aerobic culture conditions. The sensitivity and specificity of CDBB-TC (under aerobic culture conditions) were compared to those of CDBB (under anaerobic culture conditions) for the recovery of C. difficile from swabs collected from hospital room surfaces. CDBB-TC was significantly more sensitive than CDBB for recovering environmental C. difficile (36/41 [88%] versus 21/41 [51%], respectively; P = 0.006). C. difficile latex agglutination, an enzyme immunoassay for toxins A and B or glutamate dehydrogenase, and a PCR for toxin B genes were all effective as confirmatory tests. For 477 total environmental cultures, the specificity of CDBB-TC versus that of CDBB based upon false-positive yellow-color development of the medium without recovery of C. difficile was 100% (0 false-positive results) versus 96% (18 false-positive results), respectively. False-positive cultures for CDBB were attributable to the growth of anaerobic non-C. difficile organisms that did not grow in CDBB-TC. Our results suggest that CDBB-TC provides a sensitive and selective medium for the recovery of C. difficile organisms from environmental samples, without the need for anaerobic culture conditions.
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Abstract
Spores of Bacillus species can remain in their dormant and resistant states for years, but exposure to agents such as specific nutrients can cause spores' return to life within minutes in the process of germination. This process requires a number of spore-specific proteins, most of which are in or associated with the inner spore membrane (IM). These proteins include the (i) germinant receptors (GRs) that respond to nutrient germinants, (ii) GerD protein, which is essential for GR-dependent germination, (iii) SpoVA proteins that form a channel in spores' IM through which the spore core's huge depot of dipicolinic acid is released during germination, and (iv) cortex-lytic enzymes (CLEs) that degrade the large peptidoglycan cortex layer, allowing the spore core to take up much water and swell, thus completing spore germination. While much has been learned about nutrient germination, major questions remain unanswered, including the following. (i) How do nutrient germinants penetrate through spores' outer layers to access GRs in the IM? (ii) What happens during the highly variable and often long lag period between the exposure of spores to nutrient germinants and the commitment of spores to germinate? (iii) What do GRs and GerD do, and how do these proteins interact? (iv) What is the structure of the SpoVA channel in spores' IM, and how is this channel gated? (v) What is the precise state of the spore IM, which has a number of novel properties even though its lipid composition is very similar to that of growing cells? (vi) How is CLE activity regulated such that these enzymes act only when germination has been initiated? (vii) And finally, how does the germination of spores of clostridia compare with that of spores of bacilli?
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