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Jia T, Xu T, Xia J, Liu S, Li W, Xu R, Kong J, Zhang Q. Clinical protective effects of polyhexamethylene biguanide hydrochloride (PHMB) against Vibrio parahaemolyticus causing translucent post-larvae disease (V pTPD) in Penaeus vannamei. J Invertebr Pathol 2023; 201:108002. [PMID: 37838066 DOI: 10.1016/j.jip.2023.108002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 09/29/2023] [Accepted: 10/11/2023] [Indexed: 10/16/2023]
Abstract
A new emerging disease called "translucent post-larvae disease" (TPD) in Penaeus vannamei, caused by a novel type of highly lethal Vibro parahaemolyticus (VpTPD), has become an urgent threat to the shrimp farming industry in China. In order to develop an effective disinfectant for the prevention and control of the VpTPD, the clinical protective effects of polyhexamethylene biguanide hydrochloride (PHMB) against VpTPD in Penaeus vannamei were investigated by carrying out an acute toxicity test of PHMB on post-larvae of P. vannamei and its effect of treatment test on VpTPD infection. The results showed that the median lethal concentration of disinfectant (LC50) values of PHMB to post-larvae of P. vannamei after treatment for 24 h, 48 h, 72 h, 96 h were 16.13 mg/L (14.18-18.57), 10.77 mg/L (9.93-11.72), 9.68 mg/L (8.53-11.64), 9.14 mg/L (7.70-10.99), respectively. In addition, a clinical trial showed that 1 mg/L PHMB showed a strong protective effect on the post-larvae of shrimp challenged with 101-104 CFU/ml of VpTPD. The relative percentage survival (RPS) of 1 mg/L PHMB on post-larvae of P. vannamei challenged with VpTPD at 101, 102, 103 and 104 CFU/ml were 63.65 %±6.81, 62.96 %±5.56, 60.00 %±3.75 and 66.67 %±3.75 at 96 hours post infection. The results highlight the clinical protective effects of the PHMB and therefor PHMB can be used as a preventive measure to control early TPD infection in shrimp culture. This study also provides valuable information for the prevention of other bacterial diseases in shrimp culture.
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Affiliation(s)
- Tianchang Jia
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Tingting Xu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Jitao Xia
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China
| | - Shuang Liu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Wenqiang Li
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China
| | - Ruidong Xu
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China
| | - Jie Kong
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China
| | - Qingli Zhang
- State Key Laboratory of Mariculture Biobreeding and Sustainable Goods; Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture; Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity; Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, Shandong 266071, China; Laboratory for Marine Fisheries Science and Food Production Processes, Laoshan Laboratory, Qingdao, Shandong 266237, China.
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2
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Kapinusova G, Lopez Marin MA, Uhlik O. Reaching unreachables: Obstacles and successes of microbial cultivation and their reasons. Front Microbiol 2023; 14:1089630. [PMID: 36960281 PMCID: PMC10027941 DOI: 10.3389/fmicb.2023.1089630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 02/10/2023] [Indexed: 03/09/2023] Open
Abstract
In terms of the number and diversity of living units, the prokaryotic empire is the most represented form of life on Earth, and yet it is still to a significant degree shrouded in darkness. This microbial "dark matter" hides a great deal of potential in terms of phylogenetically or metabolically diverse microorganisms, and thus it is important to acquire them in pure culture. However, do we know what microorganisms really need for their growth, and what the obstacles are to the cultivation of previously unidentified taxa? Here we review common and sometimes unexpected requirements of environmental microorganisms, especially soil-harbored bacteria, needed for their replication and cultivation. These requirements include resuscitation stimuli, physical and chemical factors aiding cultivation, growth factors, and co-cultivation in a laboratory and natural microbial neighborhood.
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Affiliation(s)
| | | | - Ondrej Uhlik
- Department of Biochemistry and Microbiology, Faculty of Food and Biochemical Technology, University of Chemistry and Technology, Prague, Czechia
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3
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Wake Up! Resuscitation of Viable but Nonculturable Bacteria: Mechanism and Potential Application. Foods 2022; 12:foods12010082. [PMID: 36613298 PMCID: PMC9818539 DOI: 10.3390/foods12010082] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/12/2022] [Accepted: 12/16/2022] [Indexed: 12/29/2022] Open
Abstract
The viable but nonculturable (VBNC) state is a survival strategy for bacteria when encountered with unfavorable conditions. Under favorable environments such as nutrient supplementation, external stress elimination, or supplementation with resuscitation-promoting substances, bacteria will recover from the VBNC state, which is termed "resuscitation". The resuscitation phenomenon is necessary for proof of VBNC existence, which has been confirmed in different ways to exclude the possibility of culturable-cell regrowth. The resuscitation of VBNC cells has been widely studied for the purpose of risk control of recovered pathogenic or spoilage bacteria. From another aspect, the resuscitation of functional bacteria can also be considered a promising field to explore. To support this point, the resuscitation mechanisms were comprehensively reviewed, which could provide the theoretical foundations for the application of resuscitated VBNC cells. In addition, the proposed applications, as well as the prospects for further applications of resuscitated VBNC bacteria in the food industry are discussed in this review.
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4
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A double layer agar plate method results in an improvement for enumerating Vibrio vulnificus and Vibrio parahaemolyticus exposed to nutrient deficiency and refrigeration temperature. Food Microbiol 2022; 107:104085. [DOI: 10.1016/j.fm.2022.104085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/15/2022] [Accepted: 06/17/2022] [Indexed: 11/22/2022]
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CAMPYAIR, a New Selective, Differential Medium for Campylobacter spp. Isolation without the Need for Microaerobic Atmosphere. Microorganisms 2022; 10:microorganisms10071403. [PMID: 35889122 PMCID: PMC9318433 DOI: 10.3390/microorganisms10071403] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 02/01/2023] Open
Abstract
Campylobacter spp. are considered the most frequent bacterial cause of acute gastroenteritis worldwide. Although the diarrhea produced by these bacteria is self-limiting, the pathogen has been associated with severe long-term sequelae following acute signs and symptoms of the illness. However, research on Campylobacter is hampered by costs and technical requirements for isolating and culturing the bacterium, especially in low and middle-income countries. Therefore, attempts have been made to simplify these culture methods and to reduce costs associated with conducting research on Campylobacter. Recently, a liquid medium which allows selective enrichment of Campylobacter using aerobic incubation has been described. However, a solid medium is also needed for the isolation of pure colonies, enumeration of bacterial populations, and other studies on the pathogen. Therefore, a new medium (CAMPYAIR) was developed, based on the formulation of the liquid medium. CAMPYAIR is a solid chromogenic medium that supports the growth of Campylobacter isolates within 48 h of incubation in aerobic atmospheres. Moreover, CAMPYAIR contains antibiotic supplements with an enhanced ability to recover Campylobacter from environmental samples that may also contain non-campylobacter bacteria. The addition of the indicator 2,3,5-triphenyltetrazolium (TTC) to the medium differentiates Campylobacter from other bacteria growing on the media. The findings from studies on CAMPYAIR suggest that the utilization of the new selective, differential medium could help to reduce the costs, equipment, and technical training required for Campylobacter isolation from clinical and environmental samples.
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Auty JM, Jenkins CH, Hincks J, Straatman-Iwanowska AA, Allcock N, Turapov O, Galyov EE, Harding SV, Mukamolova GV. Generation of Distinct Differentially Culturable Forms of Burkholderia following Starvation at Low Temperature. Microbiol Spectr 2022; 10:e0211021. [PMID: 34985335 PMCID: PMC8729786 DOI: 10.1128/spectrum.02110-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 12/04/2021] [Indexed: 11/20/2022] Open
Abstract
Bacteria have developed unique mechanisms to adapt to environmental stresses and challenges of the immune system. Here, we report that Burkholderia pseudomallei, the causative agent of melioidosis, and its laboratory surrogate, Burkholderia thailandensis, utilize distinct mechanisms for surviving starvation at different incubation temperatures. At 21°C, Burkholderia are present as short rods which can rapidly reactivate and form colonies on solid media. At 4°C, Burkholderia convert into coccoid forms that cannot be cultured on solid agar but can be resuscitated in liquid media supplemented with supernatant obtained from logarithmic phase cultures of B. thailandensis, or catalase and Tween 80, thus displaying characteristics of differentially culturable bacteria (DCB). These DCB have low intensity fluorescence when stained with SYTO 9, have an intact cell membrane (propidium iodide negative), and contain 16S rRNA at levels comparable with growing cells. We also present evidence that lytic transglycosylases, a family of peptidoglycan-remodeling enzymes, are involved in the generation of coccoid forms and their resuscitation to actively growing cells. A B. pseudomallei ΔltgGCFD mutant with four ltg genes deleted did not produce coccoid forms at 4°C and could not be resuscitated in the liquid media evaluated. Our findings provide insights into the adaptation of Burkholderia to nutrient limitation and the generation of differentially culturable bacteria. IMPORTANCE Bacterial pathogens exhibit physiologically distinct forms that enable their survival in an infected host, the environment and following exposure to antimicrobial agents. B. pseudomallei causes the disease melioidosis, which has a high mortality rate and is difficult to treat with antibiotics. The bacterium is endemic to several countries and detected in high abundance in the environment. Here, we report that during starvation at low temperature, B. pseudomallei produces coccoid forms that cannot grow in standard media and which, therefore, can be challenging to detect using common tools. We provide evidence that the formation of these cocci is mediated by cell wall-specialized enzymes and lytic transglycosylases, and that resuscitation of these forms occurs following the addition of catalase and Tween 80. Our findings have important implications for the disease control and detection of B. pseudomallei, an agent of both public health and defense interest.
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Affiliation(s)
- Joss M. Auty
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Christopher H. Jenkins
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Jennifer Hincks
- FACS Facility Core Biotechnology Services, University of Leicester, Leicester, United Kingdom
| | - Anna A. Straatman-Iwanowska
- Electron Microscopy Facility, Core Biotechnology Services, University of Leicester, Leicester, United Kingdom
| | - Natalie Allcock
- Electron Microscopy Facility, Core Biotechnology Services, University of Leicester, Leicester, United Kingdom
| | - Obolbek Turapov
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
| | - Edouard E. Galyov
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
| | - Sarah V. Harding
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
- Defence Science and Technology Laboratory, Chemical, Biological and Radiological Division, Porton Down, Salisbury, Wiltshire, United Kingdom
| | - Galina V. Mukamolova
- Department of Respiratory Sciences, University of Leicester, Leicester, United Kingdom
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7
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Wendel U. Assessing Viability and Stress Tolerance of Probiotics—A Review. Front Microbiol 2022; 12:818468. [PMID: 35154042 PMCID: PMC8829321 DOI: 10.3389/fmicb.2021.818468] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/27/2021] [Indexed: 11/26/2022] Open
Abstract
The interest in probiotics has increased rapidly the latest years together with the global market for probiotic products. Consequently, establishing reliable microbiological methods for assuring the presence of a certain number of viable microorganisms in probiotic products has become increasingly important. To assure adequate numbers of viable cells, authorities are enquiring for information on viability rates within a certain shelf-life in colony forming units (CFU). This information is obtained from plate count enumeration, a method that enables detection of bacterial cells based on their ability to replicate. Although performing plate count enumeration is one manner of assessing viability, cells can still be viable without possessing the ability to replicate. Thus, to properly assess probiotic viability, further analysis of a broader group of characteristics using several types of methods is proposed. In addition to viability, it is crucial to identify how well the cells in a probiotic product can survive in the gastrointestinal tract (GIT) and thus be able to mediate the desired health benefit while passing through the human body. A broad spectrum of different assay designs for assessing probiotic gastric tolerance have been used in research and quality control. However, the absence of any consensus on how to assess these qualities makes it difficult to compare between laboratories and to translate the results into in vivo tolerance. This review presents and discusses the complexity of assuring that a probiotic is suitable for beneficial consumption. It summarizes the information that can be subtracted from the currently available methods for assessment of viability and stress tolerance of a probiotic, hereby altogether defined as “activity.” Strengths and limitations of the different methods are presented together with favorable method combinations. Finally, the importance of choosing a set of analyses that reveals the necessary aspects of probiotic activity for a certain product or application is emphasized.
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8
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Song S, Wood TK. 'Viable but non-culturable cells' are dead. Environ Microbiol 2021; 23:2335-2338. [PMID: 33723898 DOI: 10.1111/1462-2920.15463] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 03/12/2021] [Indexed: 12/23/2022]
Abstract
Most bacteria lead lives of quiet desperation, so they sleep. By sleeping, bacteria survive ubiquitous stress, such as antibiotics, and can resuscitate to reconstitute infections. As for other nearly universal and highly regulated processes such as biofilm formation, in persistence, a small population of cells have an elegantly-regulated pathway to become dormant. By inactivating their ribosomes, persister cells sleep through stress and resuscitate once (i) the stress is removed, (ii) nutrients are presented and (iii) ribosome content reaches a threshold. During stress, cells often become spheroid and die, becoming hollow, membrane-enclosed vessels. How cellular content is lost is unclear, but it is obvious that these 'cell shells' are dead; i.e., 'There's no there there'. Critically, due to their intact membranes, the shells appear with membrane-impenetrant stains as 'viable' particles. Unfortunately, the microbiology field of 'viable but non-culturable cells' (VBNCs), though important for demonstrating the existence of dormant bacteria as a result of myriad stress states, has often mistaken these non-viable shells as viable particles that mysteriously may be reborn, when an appropriate incantation is made. We argue here, based on experimental data, that if resuscitation occurs, it is the persister (always-viable) cell population that revives, rather than the cell husks, which are dead.
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Affiliation(s)
- Sooyeon Song
- Department of Animal Science, Jeonbuk National University, Jeonju-si, Jeollabuk-do, 54896, South Korea
| | - Thomas K Wood
- Department of Chemical Engineering, Pennsylvania State University, University Park, PA, 16802-4400, USA
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9
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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10
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Hahn MW, Koll U, Schmidt J. Isolation and Cultivation of Bacteria. ADVANCES IN ENVIRONMENTAL MICROBIOLOGY 2019. [DOI: 10.1007/978-3-030-16775-2_10] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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11
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Chen S, Li X, Wang Y, Zeng J, Ye C, Li X, Guo L, Zhang S, Yu X. Induction of Escherichia coli into a VBNC state through chlorination/chloramination and differences in characteristics of the bacterium between states. WATER RESEARCH 2018; 142:279-288. [PMID: 29890476 DOI: 10.1016/j.watres.2018.05.055] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 05/22/2018] [Accepted: 05/29/2018] [Indexed: 05/22/2023]
Abstract
Many pathogens can enter into a viable but nonculturable (VBNC) state in response to harsh environmental stresses. Bacteria in this state can retain certain features of viable cells, such as cellular integrity, metabolic activity, or virulence and may present health risks associated with drinking water. In this study, we investigated the ability of chlorination and chloramination, which are widely used methods to disinfect drinking water, to induce Escherichia coli into a VBNC state. After treatment with chlorine and chloramine at concentrations of 1, 2, 3, and 4 mg/L, the counts of culturable E. coli cells decreased from 106 CFU/mL to 0 CFU/mL at 5-60 min post treatment. Meanwhile, viable cell counts were still approximately 103-105 cells/mL. These viable E. coli cells may be induced into a VBNC state by chlorination and chloramination. Scanning electron microscopy and laser confocal microscopy showed that some bacteria maintained cellular integrity, but the average length of VBNC cells was less than that of culturable cells. Respiratory activity of VBNC cells decreased approximately 50% relative to that of culturable cells. We also used heavy water (D2O) combined with Raman microspectroscopy to show that E. coli in a VBNC state retained metabolic activity involving water (e.g. condensation reactions) at the single-cell level. Furthermore, soxR, gadA, and katG genes remained highly expressed, suggesting that VBNC cells were physiologically active. Finally, resuscitation of VBNC cells induced by chlorine in Luria-Bertani (LB) broth was identified by calculating the generation time. Results of this study will facilitate a better understanding of the health risks associated with VBNC bacteria and the development of more effective strategies for drinking water disinfection.
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Affiliation(s)
- Sheng Chen
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Xi Li
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Yahong Wang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Jie Zeng
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Chengsong Ye
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China
| | - Xianping Li
- College of Environment & Ecology, Xiamen University, Xiamen 361021, PR China
| | - Lizheng Guo
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China
| | - Shenghua Zhang
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
| | - Xin Yu
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, PR China.
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12
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Mendis N, Trigui H, Saad M, Tsang A, Faucher SP. Deletion of oxyR in Legionella pneumophila causes growth defect on agar. Can J Microbiol 2018; 64:1030-1041. [PMID: 30212639 DOI: 10.1139/cjm-2018-0129] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The intracellular pathogen Legionella pneumophila (Lp) is a strict aerobe, surviving and replicating in environments where it frequently encounters reactive oxygen species (ROS), such as the nutrient-poor water environment and its replicative niche inside host cells. In many proteobacteria, the LysR-type regulator OxyR controls the oxidative stress response; however, the importance of the OxyR homologue in Lp is still unclear. Therefore, we undertook the characterization of phenotypes associated with the deletion of oxyR in Lp. Contrary to the wild type, the oxyR deletion mutant exhibits a severe growth defect on charcoal - yeast extract (CYE) agar lacking α-ketoglutarate supplementation. Growth in AYE broth (CYE without agar and charcoal), in amoeba and in human cultured macrophages, and survival in water is unaffected by the deletion. Supplementing CYE agar with antioxidants that neutralize ROS or introducing the oxyR gene in trans rescues the observed growth defect. Moreover, the mutant grows as well as the wild type on CYE plates made with agarose instead of agar, suggesting that a compound present in the latter is responsible for the growth defect phenotype.
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Affiliation(s)
- Nilmini Mendis
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Hana Trigui
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Mariam Saad
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Adrianna Tsang
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
| | - Sébastien P Faucher
- Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada.,Department of Natural Resource Sciences, McGill University, Sainte-Anne-de-Bellevue, QC H9X 3V9, Canada
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13
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Role of food sanitising treatments in inducing the ‘viable but nonculturable’ state of microorganisms. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.04.016] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Kim HM, Yoon CK, Ham HI, Seok YJ, Park YH. Stimulation of Vibrio vulnificus Pyruvate Kinase in the Presence of Glucose to Cope With H 2O 2 Stress Generated by Its Competitors. Front Microbiol 2018; 9:1112. [PMID: 29896177 PMCID: PMC5987630 DOI: 10.3389/fmicb.2018.01112] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 05/11/2018] [Indexed: 01/29/2023] Open
Abstract
The bacterial phosphoenolpyruvate (PEP):carbohydrate phosphotransferase system (PTS) regulates a variety of cellular processes in addition to catalyzing the coupled transport and phosphorylation of carbohydrates. We recently reported that, in the presence of glucose, HPr of the PTS is dephosphorylated and interacts with pyruvate kinase A (PykA) catalyzing the conversion of PEP to pyruvate in Vibrio vulnificus. Here, we show that this interaction enables V. vulnificus to survive H2O2 stress by increasing pyruvate production. A pykA deletion mutant was more susceptible to H2O2 stress than wild-type V. vulnificus without any decrease in the expression level of catalase, and this sensitivity was rescued by the addition of pyruvate. The H2O2 sensitivity difference between wild-type and pykA mutant strains becomes more apparent in the presence of glucose. Fungi isolated from the natural habitat of V. vulnificus retarded the growth of the pykA mutant more severely than the wild-type strain in the presence of glucose by glucose oxidase-dependent generation of H2O2. These data suggest that V. vulnificus has evolved to resist the killing action of its fungal competitors by increasing pyruvate production in the presence of glucose.
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Affiliation(s)
- Hey-Min Kim
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, South Korea
| | - Chang-Kyu Yoon
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, South Korea
| | - Hyeong-In Ham
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, South Korea
| | - Yeong-Jae Seok
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, South Korea
| | - Young-Ha Park
- School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, South Korea
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15
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Li X, Imlay JA. Improved measurements of scant hydrogen peroxide enable experiments that define its threshold of toxicity for Escherichia coli. Free Radic Biol Med 2018; 120:217-227. [PMID: 29550333 PMCID: PMC5940505 DOI: 10.1016/j.freeradbiomed.2018.03.025] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/12/2018] [Accepted: 03/13/2018] [Indexed: 01/06/2023]
Abstract
Escherichia coli is a model organism that has been exploited to reveal key details of hydrogen peroxide stress: the biomolecules that H2O2 most rapidly damages and the defensive tactics that organisms use to fend it off. Much less clear is the amount of exogenous H2O2 that is sufficient to injure the bacterium and/or to trigger its stress response. To fill this gap, we need to study the behavior of cells when they are exposed to defined amounts of H2O2 on an hours-long time scale. Such experiments are difficult because bacteria rapidly consume H2O2 that is added to test cultures. Further, lab media itself can generate H2O2, and media components interfere with the quantification of H2O2 levels. In this study we describe mechanisms by which media components interfere with H2O2 determinations, and we identify simple ways to minimize and correct for this interference. Using these techniques, it was shown that standard media generate so much H2O2 that most intracellular H2O2 derives from the medium rather than from endogenous metabolism. Indeed, bacteria spread on plates must induce their stress response or else perish. Finally, two straightforward methods were used to sustain low-micromolar steady-state concentrations of H2O2. In this way we determined that > 2 μM extracellular H2O2 is sufficient to trigger the intracellular OxyR stress response, and > 5 μM begins to impair cell growth in a minimal medium. These concentrations are orders of magnitude lower than the doses that have typically been used in lab experiments. The new approaches should enable workers to study how various organisms cope with natural levels of H2O2 stress.
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Affiliation(s)
- Xin Li
- College of Food and Bioengineering, Henan University of Science and Technology, No. 263, Kaiyuan Ave., Luoyang, Henan 471023, China.
| | - James A Imlay
- Department of Microbiology, University of Illinois, 601 S. Goodwin Ave., Urbana, IL 61801, USA.
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16
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Gordeev AA, Chetverin AB. Methods for Screening Live Cells. BIOCHEMISTRY (MOSCOW) 2018; 83:S81-S102. [DOI: 10.1134/s0006297918140080] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Ochiai Y, Yamada F, Yoshikawa Y, Mochizuki M, Takano T, Hondo R, Ueda F. Sequential transition of the injury phenotype, temperature-dependent survival and transcriptional response in Listeria monocytogenes following lethal H 2 O 2 exposure. Int J Food Microbiol 2017; 259:52-58. [DOI: 10.1016/j.ijfoodmicro.2017.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 07/29/2017] [Accepted: 08/01/2017] [Indexed: 11/29/2022]
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18
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Li T, Li CT, Butler K, Hays SG, Guarnieri MT, Oyler GA, Betenbaugh MJ. Mimicking lichens: incorporation of yeast strains together with sucrose-secreting cyanobacteria improves survival, growth, ROS removal, and lipid production in a stable mutualistic co-culture production platform. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:55. [PMID: 28344645 PMCID: PMC5360037 DOI: 10.1186/s13068-017-0736-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 02/17/2017] [Indexed: 05/04/2023]
Abstract
BACKGROUND The feasibility of heterotrophic-phototrophic symbioses was tested via pairing of yeast strains Cryptococcus curvatus, Rhodotorula glutinis, or Saccharomyces cerevisiae with a sucrose-secreting cyanobacterium Synechococcus elongatus. RESULTS The phototroph S. elongatus showed no growth in standard BG-11 medium with yeast extract, but grew well in BG-11 medium alone or supplemented with yeast nitrogen base without amino acids (YNB w/o aa). Among three yeast species, C. curvatus and R. glutinis adapted well to the BG-11 medium supplemented with YNB w/o aa, sucrose, and various concentrations of NaCl needed to maintain sucrose secretion from S. elongatus, while growth of S. cerevisiae was highly dependent on sucrose levels. R. glutinis and C. curvatus grew efficiently and utilized sucrose produced by the partner in co-culture. Co-cultures of S. elongatus and R. glutinis were sustained over 1 month in both batch and in semi-continuous culture, with the final biomass and overall lipid yields in the batch co-culture 40 to 60% higher compared to batch mono-cultures of S. elongatus. The co-cultures showed enhanced levels of palmitoleic and linoleic acids. Furthermore, cyanobacterial growth in co-culture with R. glutinis was significantly superior to axenic growth, as S. elongatus was unable to grow in the absence of the yeast partner when cultivated at lower densities in liquid medium. Accumulated reactive oxygen species was observed to severely inhibit axenic growth of cyanobacteria, which was efficiently alleviated through catalase supply and even more effectively with co-cultures of R. glutinis. CONCLUSIONS The pairing of a cyanobacterium and eukaryotic heterotroph in the artificial lichen of this study demonstrates the importance of mutual interactions between phototrophs and heterotrophs, e.g., phototrophs provide a carbon source to heterotrophs, and heterotrophs assist phototrophic growth and survival by removing/eliminating oxidative stress. Our results establish a potential stable production platform that combines the metabolic capability of photoautotrophs to capture inorganic carbon with the channeling of the resulting organic carbon directly to a robust heterotroph partner for producing biofuel and other chemical precursors.
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Affiliation(s)
- Tingting Li
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Chien-Ting Li
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Kirk Butler
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Stephanie G. Hays
- Department of Systems Biology, Harvard Medical School, Boston, MA 02115 USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115 USA
| | - Michael T. Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401 USA
| | - George A. Oyler
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
| | - Michael J. Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218 USA
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19
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Li H, Gänzle M. Some Like It Hot: Heat Resistance of Escherichia coli in Food. Front Microbiol 2016; 7:1763. [PMID: 27857712 PMCID: PMC5093140 DOI: 10.3389/fmicb.2016.01763] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/20/2016] [Indexed: 11/13/2022] Open
Abstract
Heat treatment and cooking are common interventions for reducing the numbers of vegetative cells and eliminating pathogenic microorganisms in food. Current cooking method requires the internal temperature of beef patties to reach 71°C. However, some pathogenic Escherichia coli such as the beef isolate E. coli AW 1.7 are extremely heat resistant, questioning its inactivation by current heat interventions in beef processing. To optimize the conditions of heat treatment for effective decontaminations of pathogenic E. coli strains, sufficient estimations, and explanations are necessary on mechanisms of heat resistance of target strains. The heat resistance of E. coli depends on the variability of strains and properties of food formulations including salt and water activity. Heat induces alterations of E. coli cells including membrane, cytoplasm, ribosome and DNA, particularly on proteins including protein misfolding and aggregations. Resistant systems of E. coli act against these alterations, mainly through gene regulations of heat response including EvgA, heat shock proteins, σE and σS, to re-fold of misfolded proteins, and achieve antagonism to heat stress. Heat resistance can also be increased by expression of key proteins of membrane and stabilization of membrane fluidity. In addition to the contributions of the outer membrane porin NmpC and overcome of osmotic stress from compatible solutes, the new identified genomic island locus of heat resistant performs a critical role to these highly heat resistant strains. This review aims to provide an overview of current knowledge on heat resistance of E. coli, to better understand its related mechanisms and explore more effective applications of heat interventions in food industry.
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Affiliation(s)
- Hui Li
- Department of Agricultural, Food and Nutritional Science, University of Alberta, EdmontonAB, Canada
| | - Michael Gänzle
- Department of Agricultural, Food and Nutritional Science, University of Alberta, EdmontonAB, Canada
- College of Bioengineering and Food Science, Hubei University of TechnologyHubei, China
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20
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Kobayashi N, Yamazaki T, Maesaki S. Bacteriological Monitoring of Water Reservoirs in Oxygen Humidifiers: Safety of Prolonged and Multipatient Use of Prefilled Disposable Oxygen Humidifier Bottles. Infect Control Hosp Epidemiol 2016; 27:320-2. [PMID: 16532426 DOI: 10.1086/503300] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2003] [Accepted: 02/11/2004] [Indexed: 11/04/2022]
Abstract
Bacterial colony counts in water specimens from oxygen humidifiers that used reusable water reservoirs were compared with counts in water specimens from humidifiers that used prefilled disposable reservoir bottles to evaluate the effects of prolonged and multipatient use of humidifiers. Bacteria were detected after 1 week of operation in water specimens collected from many humidifiers with reusable reservoirs, but no bacteria were detected in water specimens from disposable bottles for up to 12 weeks during use of the humidifier by multiple patients.
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Affiliation(s)
- Nobuharu Kobayashi
- Department of Microbiology, Saitama Medical School, Moroyama, Iruma-gun, Saitama, Japan
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21
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Imamura D, Mizuno T, Miyoshi SI, Shinoda S. Stepwise changes in viable but nonculturable Vibrio cholerae cells. Microbiol Immunol 2016; 59:305-10. [PMID: 25664673 DOI: 10.1111/1348-0421.12246] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 02/03/2015] [Accepted: 02/06/2015] [Indexed: 11/26/2022]
Abstract
Many bacterial species are known to become viable but nonculturable (VBNC) under conditions that are unsuitable for growth. In this study, the requirements for resuscitation of VBNC-state Vibrio cholerae cells were found to change over time. Although VBNC cells could initially be converted to culturable by treatment with catalase or HT-29 cell extract, they subsequently entered a state that was not convertible to culturable by these factors. However, fluorescence microscopy revealed the presence of live cells in this state, from which VBNC cells were resuscitated by co-cultivation with HT-29 human colon adenocarcinoma cells. Ultimately, all cells entered a state from which they could not be resuscitated, even by co-cultivation with HT-29. These characteristic changes in VBNC-state cells were a common feature of strains in both V. cholerae O1 and O139 serogroups. Thus, the VBNC state of V. cholerae is not a single property but continues to change over time.
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Affiliation(s)
- Daisuke Imamura
- Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, First Floor ID Hospital Campus, 57 Dr. S. C. Banerjee Road, Beliaghata, Kolkata, 700010, India
| | - Tamaki Mizuno
- Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, First Floor ID Hospital Campus, 57 Dr. S. C. Banerjee Road, Beliaghata, Kolkata, 700010, India
| | - Shin-ichi Miyoshi
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 1-1-1 Tsushima-naka, Kita-ku, Okayama, 700-8530, Japan
| | - Sumio Shinoda
- Collaborative Research Center of Okayama University for Infectious Diseases in India, National Institute of Cholera and Enteric Diseases, First Floor ID Hospital Campus, 57 Dr. S. C. Banerjee Road, Beliaghata, Kolkata, 700010, India
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22
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Combined effect of chilling and desiccation on survival of Escherichia coli suggests a transient loss of culturability. Int J Food Microbiol 2015; 208:1-10. [DOI: 10.1016/j.ijfoodmicro.2015.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Revised: 04/14/2015] [Accepted: 04/18/2015] [Indexed: 11/23/2022]
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23
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Kim JC, Oh E, Kim J, Jeon B. Regulation of oxidative stress resistance in Campylobacter jejuni, a microaerophilic foodborne pathogen. Front Microbiol 2015; 6:751. [PMID: 26284041 PMCID: PMC4518328 DOI: 10.3389/fmicb.2015.00751] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/08/2015] [Indexed: 12/31/2022] Open
Abstract
Campylobacter jejuni is one of the leading bacterial causes of human gastroenteritis. Due to the increasing rates of human campylobacteriosis, C. jejuni is considered as a serious public health concern worldwide. C. jejuni is a microaerophilic, fastidious bacterium. C. jejuni must overcome a wide range of stress conditions during foodborne transmission to humans, such as food preservation and processing conditions, and even in infection of the gastrointestinal tracts of humans. Particularly, this microaerophilic foodborne pathogen must survive in the atmospheric conditions prior to the initiation of infection. C. jejuni possesses unique regulatory mechanisms for oxidative stress resistance. Lacking OxyR and SoxRS that are highly conserved in other Gram-negative foodborne pathogens, C. jejuni modulates the expression of genes involved in oxidative stress resistance mainly via the peroxide resistance regulator and Campylobacter oxidative stress regulator. Based on recent findings of ours and others, in this review, we described how C. jejuni regulates the expression of oxidative stress defense.
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Affiliation(s)
| | | | | | - Byeonghwa Jeon
- School of Public Health, University of Alberta, EdmontonAB, Canada
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24
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Fernández-Delgado M, García-Amado MA, Contreras M, Incani RN, Chirinos H, Rojas H, Suárez P. Survival, induction and resuscitation of Vibrio cholerae from the viable but non-culturable state in the Southern Caribbean Sea. Rev Inst Med Trop Sao Paulo 2015; 57:21-6. [PMID: 25651322 PMCID: PMC4325519 DOI: 10.1590/s0036-46652015000100003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 05/28/2014] [Indexed: 12/21/2022] Open
Abstract
The causative agent of cholera, Vibrio cholerae, can enter into a viable but non-culturable (VBNC) state in response to unfavorable conditions. The aim of this study was to evaluate the in situ survival of V. cholerae in an aquatic environment of the Southern Caribbean Sea, and its induction and resuscitation from the VBNC state. V. cholerae non-O1, non-O139 was inoculated into diffusion chambers placed at the Cuare Wildlife Refuge, Venezuela, and monitored for plate, total and viable cells counts. At 119 days of exposure to the environment, the colony count was < 10 CFU/mL and a portion of the bacterial population entered the VBNC state. Additionally, the viability decreased two orders of magnitude and morphological changes occurred from rod to coccoid cells. Among the aquatic environmental variables, the salinity had negative correlation with the colony counts in the dry season. Resuscitation studies showed significant recovery of cell cultivability with spent media addition (p < 0.05). These results suggest that V. cholerae can persist in the VBNC state in this Caribbean environment and revert to a cultivable form under favorable conditions. The VBNC state might represent a critical step in cholera transmission in susceptible areas.
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Affiliation(s)
| | - María Alexandra García-Amado
- Centro de Biofísica y Bioquímica, Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas, Altos de Pipe, Edo. Miranda, Venezuela
| | - Monica Contreras
- Centro de Biofísica y Bioquímica, Laboratorio de Fisiología Gastrointestinal, Instituto Venezolano de Investigaciones Científicas, Altos de Pipe, Edo. Miranda, Venezuela
| | - Renzo Nino Incani
- Departamento de Parasitología, Universidad de Carabobo, Valencia, Edo. Carabobo, Venezuela
| | | | - Héctor Rojas
- Instituto de Inmunología, Universidad Central de Venezuela, Caracas, Venezuela
| | - Paula Suárez
- Departamento de Biología de Organismos, Universidad Simón Bolívar, Caracas, Venezuela
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25
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A hidden pitfall in the preparation of agar media undermines microorganism cultivability. Appl Environ Microbiol 2014; 80:7659-66. [PMID: 25281372 DOI: 10.1128/aem.02741-14] [Citation(s) in RCA: 134] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Microbiologists have been using agar growth medium for over 120 years. It revolutionized microbiology in the 1890s when microbiologists were seeking effective methods to isolate microorganisms, which led to the successful cultivation of microorganisms as single clones. But there has been a disparity between total cell counts and cultivable cell counts on plates, often referred to as the "great plate count anomaly," that has long been a phenomenon that still remains unsolved. Here, we report that a common practice microbiologists have employed to prepare agar medium has a hidden pitfall: when phosphate was autoclaved together with agar to prepare solid growth media (PT medium), total colony counts were remarkably lower than those grown on agar plates in which phosphate and agar were separately autoclaved and mixed right before solidification (PS medium). We used a pure culture of Gemmatimonas aurantiaca T-27(T) and three representative sources of environmental samples, soil, sediment, and water, as inocula and compared colony counts between PT and PS agar plates. There were higher numbers of CFU on PS medium than on PT medium using G. aurantiaca or any of the environmental samples. Chemical analysis of PT agar plates suggested that hydrogen peroxide was contributing to growth inhibition. Comparison of 454 pyrosequences of the environmental samples to the isolates revealed that taxa grown on PS medium were more reflective of the original community structure than those grown on PT medium. Moreover, more hitherto-uncultivated microbes grew on PS than on PT medium.
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26
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Salam KW, El-Fadel M, Barbour EK, Saikaly PE. A propidium monoazide–quantitative PCR method for the detection and quantification of viable Enterococcus faecalis in large-volume samples of marine waters. Appl Microbiol Biotechnol 2014; 98:8707-18. [DOI: 10.1007/s00253-014-6023-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/05/2014] [Accepted: 08/07/2014] [Indexed: 11/30/2022]
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27
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Li L, Mendis N, Trigui H, Oliver JD, Faucher SP. The importance of the viable but non-culturable state in human bacterial pathogens. Front Microbiol 2014; 5:258. [PMID: 24917854 PMCID: PMC4040921 DOI: 10.3389/fmicb.2014.00258] [Citation(s) in RCA: 546] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/12/2014] [Indexed: 12/12/2022] Open
Abstract
Many bacterial species have been found to exist in a viable but non-culturable (VBNC) state since its discovery in 1982. VBNC cells are characterized by a loss of culturability on routine agar, which impairs their detection by conventional plate count techniques. This leads to an underestimation of total viable cells in environmental or clinical samples, and thus poses a risk to public health. In this review, we present recent findings on the VBNC state of human bacterial pathogens. The characteristics of VBNC cells, including the similarities and differences to viable, culturable cells and dead cells, and different detection methods are discussed. Exposure to various stresses can induce the VBNC state, and VBNC cells may be resuscitated back to culturable cells under suitable stimuli. The conditions that trigger the induction of the VBNC state and resuscitation from it are summarized and the mechanisms underlying these two processes are discussed. Last but not least, the significance of VBNC cells and their potential influence on human health are also reviewed.
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Affiliation(s)
- Laam Li
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - Nilmini Mendis
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - Hana Trigui
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
| | - James D Oliver
- Department of Biology, University of North Carolina at Charlotte Charlotte, NC, USA
| | - Sebastien P Faucher
- Department of Natural Resource Sciences, Faculty of Agricultural and Environmental Sciences, McGill University Ste-Anne-de-Bellevue, QC, Canada
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28
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Jeffrey Morris J, Zinser ER. Continuous hydrogen peroxide production by organic buffers in phytoplankton culture media. JOURNAL OF PHYCOLOGY 2013; 49:1223-8. [PMID: 27007639 DOI: 10.1111/jpy.12123] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/15/2013] [Indexed: 05/08/2023]
Abstract
We investigated the production of hydrogen peroxide (HOOH) in illuminated seawater media containing a variety of zwitterionic buffers. Production rates varied extensively among buffers, with 4-(2-hydroxyethyl)1-piperazineethanesulfonic acid (HEPES) highest and N-Tris(hydroxymethyl)methyl-3-aminopropanesulfonic acid (TAPS) among the lowest. The rate of HOOH accumulation was remarkably consistent over many days, and increased linearly with buffer concentration, natural seawater concentration, and light level. Concentrations of HEPES commonly used in culture media (1-10 mM) generated enough HOOH to kill the axenic Prochlorococcus strain VOL1 during growth in enriched seawater media at lower, environmentally realistic cell concentrations and/or under high light exposure. We also demonstrated that HEPES can be used experimentally to study the biological effects of chronic exposure to sublethal levels of HOOH such as may be experienced by light-exposed microorganisms.
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Affiliation(s)
- J Jeffrey Morris
- Department of Microbiology and Molecular Genetics, Michigan State University, 567 Wilson Road #6140, East Lansing, Michigan, 48824, USA
| | - Erik R Zinser
- Department of Microbiology, University of Tennessee Knoxville, M409 Walters Life Sciences, Knoxville, Tennesse, 37996, USA
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29
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Pinto D, Santos MA, Chambel L. Thirty years of viable but nonculturable state research: unsolved molecular mechanisms. Crit Rev Microbiol 2013; 41:61-76. [PMID: 23848175 DOI: 10.3109/1040841x.2013.794127] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Viable but nonculturable (VBNC) cells were recognized 30 years ago; and despite decades of research on the topic, most results are disperse and apparently incongruous. Since its description, a huge controversy arose regarding the ecological significance of this state: is it a degradation process without real significance for bacterial life cycles or is it an adaptive strategy of bacteria to cope with stressful conditions? In order to solve the molecular mechanisms of VBNC state induction and resuscitation, researchers in the field must be aware and overcome common issues delaying research progress. In this review, we discuss the intrinsic characteristic features of VBNC cells, the first clues on what is behind the VBNC state's induction, the models proposed for their resuscitation and the current methods to prove not only that cells are in VBNC state but also that they are able to resuscitate.
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Affiliation(s)
- Daniela Pinto
- Center for Biodiversity, Functional and Integrative Genomics (BioFIG), Faculty of Sciences, University of Lisbon , Lisbon , Portugal
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30
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Wang HW, Chung CH, Ma TY, Wong HC. Roles of alkyl hydroperoxide reductase subunit C (AhpC) in viable but nonculturable Vibrio parahaemolyticus. Appl Environ Microbiol 2013; 79:3734-43. [PMID: 23563952 PMCID: PMC3675929 DOI: 10.1128/aem.00560-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 04/03/2013] [Indexed: 11/20/2022] Open
Abstract
Alkyl hydroperoxide reductase subunit C (AhpC) is the catalytic subunit responsible for the detoxification of reactive oxygen species that form in bacterial cells or are derived from the host; thus, AhpC facilitates the survival of pathogenic bacteria under environmental stresses or during infection. This study investigates the role of AhpC in the induction and maintenance of a viable but nonculturable (VBNC) state in Vibrio parahaemolyticus. In this investigation, ahpC1 (VPA1683) and ahpC2 (VP0580) were identified in chromosomes II and I of this pathogen, respectively. Mutants with deletions of these two ahpC genes and their complementary strains were constructed from the parent strain KX-V231. The growth of these strains was monitored on tryptic soy agar-3% NaCl in the presence of the extrinsic peroxides H(2)O(2) and tert-butyl hydroperoxide (t-BOOH) at different incubation temperatures. The results revealed that both ahpC genes were protective against t-BOOH, while ahpC1 was protective against H(2)O(2). The protective function of ahpC2 at 4°C was higher than that of ahpC1. The times required to induce the VBNC state (4.7 weeks) at 4°C in a modified Morita mineral salt solution with 0.5% NaCl and then to maintain the VBNC state (4.7 weeks) in an ahpC2 mutant and an ahpC1 ahpC2 double mutant were significantly shorter than those for the parent strain (for induction, 6.2 weeks; for maintenance, 7.8 weeks) and the ahpC1 mutant (for induction, 6.0 weeks; for maintenance, 8.0 weeks) (P < 0.03). Complementation with an ahpC2 gene reversed the effects of the ahpC2 mutation in shortening the times for induction and maintenance of the VBNC state. This investigation identified the different functions of the two ahpC genes and confirmed the particular role of ahpC2 in the VBNC state of V. parahaemolyticus.
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Affiliation(s)
- Hen-Wei Wang
- Department of Microbiology, Soochow University, Taipei, Taiwan, Republic of China
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Zhao F, Bi X, Hao Y, Liao X. Induction of viable but nonculturable Escherichia coli O157:H7 by high pressure CO2 and its characteristics. PLoS One 2013; 8:e62388. [PMID: 23626816 PMCID: PMC3633907 DOI: 10.1371/journal.pone.0062388] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 03/21/2013] [Indexed: 11/18/2022] Open
Abstract
The viable but nonculturable (VBNC) state is a survival strategy adopted by many pathogens when exposed to harsh environmental stresses. In this study, we investigated for the first time that whether high pressure CO2 (HPCD), one of the nonthermal pasteurization techniques, can induce Escherichia coli O157:H7 into the VBNC state. By measuring plate counts, viable cell counts and total cell counts, E. coli O157:H7 in 0.85% NaCl solution (pH 7.0) was able to enter the VBNC state by HPCD treatment at 5 MPa and four temperatures (25°C, 31°C, 34°C and 37°C). Meanwhile, with the improvement of treatment temperature, the time required for E. coli O157:H7 to enter VBNC state would shorten. Enzymatic activities in these VBNC cells were lower than those in the exponential-phase cells by using API ZYM kit, which were also reduced with increasing the treatment temperature, but the mechanical resistance of the VBNC cells to sonication was enhanced. These results further confirmed VBNC state was a self-protection mechanism for some bacteria, which minimized cellular energetic requirements and increased the cell resistance. When incubated in tryptic soy broth at 37°C, the VBNC cells induced by HPCD treatment at 25°C, 31°C and 34°C achieved resuscitation, but their resuscitation capabilities decreased with increasing the treatment temperature. Furthermore, electron microscopy revealed changes in the morphology and interior structure of the VBNC cells and the resuscitated cells. These results demonstrated that HPCD could induce E. coli O157:H7 into the VBNC state. Therefore, it is necessary to detect if there exist VBNC microorganisms in HPCD-treated products by molecular-based methods for food safety.
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Affiliation(s)
- Feng Zhao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Chinese National Engineering Research Centre for Fruit and Vegetable Processing, Beijing, China
- Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China
| | - Xiufang Bi
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Chinese National Engineering Research Centre for Fruit and Vegetable Processing, Beijing, China
- Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China
| | - Yanling Hao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Chinese National Engineering Research Centre for Fruit and Vegetable Processing, Beijing, China
- Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China
- * E-mail: (XJL); (YLH)
| | - Xiaojun Liao
- College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China
- Chinese National Engineering Research Centre for Fruit and Vegetable Processing, Beijing, China
- Key Lab of Fruit and Vegetable Processing, Ministry of Agriculture, Beijing, China
- * E-mail: (XJL); (YLH)
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Riggins DP, Narvaez MJ, Martinez KA, Harden MM, Slonczewski JL. Escherichia coli K-12 survives anaerobic exposure at pH 2 without RpoS, Gad, or hydrogenases, but shows sensitivity to autoclaved broth products. PLoS One 2013; 8:e56796. [PMID: 23520457 PMCID: PMC3592846 DOI: 10.1371/journal.pone.0056796] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/14/2013] [Indexed: 12/15/2022] Open
Abstract
Escherichia coli and other enteric bacteria survive exposure to extreme acid (pH 2 or lower) in gastric fluid. Aerated cultures survive via regulons expressing glutamate decarboxylase (Gad, activated by RpoS), cyclopropane fatty acid synthase (Cfa) and others. But extreme-acid survival is rarely tested under low oxygen, a condition found in the stomach and the intestinal tract. We observed survival of E. coli K-12 W3110 at pH 1.2–pH 2.0, conducting all manipulations (overnight culture at pH 5.5, extreme-acid exposure, dilution and plating) in a glove box excluding oxygen (10% H2, 5% CO2, balance N2). With dissolved O2 concentrations maintained below 6 µM, survival at pH 2 required Cfa but did not require GadC, RpoS, or hydrogenases. Extreme-acid survival in broth (containing tryptone and yeast extract) was diminished in media that had been autoclaved compared to media that had been filtered. The effect of autoclaved media on extreme-acid survival was most pronounced when oxygen was excluded. Exposure to H2O2 during extreme-acid treatment increased the death rate slightly for W3110 and to a greater extent for the rpoS deletion strain. Survival at pH 2 was increased in strains lacking the anaerobic regulator fnr. During anaerobic growth at pH 5.5, strains deleted for fnr showed enhanced transcription of acid-survival genes gadB, cfa, and hdeA, as well as catalase (katE). We show that E. coli cultured under oxygen exclusion (<6 µM O2) requires mechanisms different from those of aerated cultures. Extreme acid survival is more sensitive to autoclave products under oxygen exclusion.
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Affiliation(s)
- Daniel P. Riggins
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
| | - Maria J. Narvaez
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
| | - Keith A. Martinez
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
| | - Mark M. Harden
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
| | - Joan L. Slonczewski
- Department of Biology, Kenyon College, Gambier, Ohio, United States of America
- * E-mail:
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Lin M, Schwarz JR. Seasonal shifts in population structure of Vibrio vulnificus in an estuarine environment as revealed by partial 16S ribosomal DNA sequencing. FEMS Microbiol Ecol 2012; 45:23-7. [PMID: 19719603 DOI: 10.1016/s0168-6496(03)00091-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Abstract The partial sequence (600 bp) containing the most variable region of Vibrio vulnificus 16S ribosomal DNA (rDNA) was determined for 208 randomly selected V. vulnificus strains isolated from Galveston Bay, TX, USA between June 2000 and June 2001. A comparative analysis of the determined partial 16S rDNA sequences revealed the existence of two different partial 16S rDNA sequences (type A and type B, 1.3% base substitutions) among the 208 V. vulnificus isolates. A higher proportion of 16S rDNA type A strains was isolated in June and July while a considerably higher proportion of type B strains was isolated in September. In addition, after no V. vulnificus strains were detected during the winter months (December-February), only type A strains were isolated during the following months (March-May). The results suggest that the relative abundance of type A and type B V. vulnificus strains in Galveston Bay varies with the season and that the differences between the two 16S rDNA types may affect the viability of these organisms in the natural environment.
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Affiliation(s)
- Meilan Lin
- Department of Marine Biology, Texas A&M University at Galveston, 5007 Avenue U, Galveston, TX 77551, USA
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Mechanisms for photoinactivation of Enterococcus faecalis in seawater. Appl Environ Microbiol 2012; 78:7776-85. [PMID: 22941072 DOI: 10.1128/aem.02375-12] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Field studies in fresh and marine waters consistently show diel fluctuations in concentrations of enterococci, indicators of water quality. We investigated sunlight inactivation of Enterococcus faecalis to gain insight into photoinactivation mechanisms and cellular responses to photostress. E. faecalis bacteria were exposed to natural sunlight in clear, filtered seawater under both oxic and anoxic conditions to test the relative importance of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. Multiple methods were used to assess changes in bacterial concentration, including cultivation, quantitative PCR (qPCR), propidium monoazide (PMA)-qPCR, LIVE/DEAD staining using propidium iodide (PI), and cellular activity, including ATP concentrations and expression of the superoxide dismutase-encoding gene, sodA. Photoinactivation, based on numbers of cultivable cells, was faster in oxic than in anoxic microcosms exposed to sunlight, suggesting that oxygen-mediated photoinactivation dominated. There was little change in qPCR signal over the course of the experiment, demonstrating that the nucleic acid targets were not damaged to a significant extent. The PMA-qPCR signal was also fairly stable, consistent with the observation that the fraction of PI-permeable cells was constant. Thus, damage to the membrane was minimal. Microbial ATP concentrations decreased in all microcosms, particularly the sunlit oxic microcosms. The increase in relative expression of the sodA gene in the sunlit oxic microcosms suggests that cells were actively responding to oxidative stress. Dark repair was not observed. This research furthers our understanding of photoinactivation mechanisms and the conditions under which diel fluctuations in enterococci can be expected in natural and engineered systems.
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Kryazhevskikh NA, Demkina EV, Manucharova NA, Soina VS, Gal’chenko VF, El’-Registan GI. Reactivation of dormant and nonculturable bacterial forms from paleosoils and subsoil permafrost. Microbiology (Reading) 2012. [DOI: 10.1134/s0026261712040108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Mishra A, Taneja N, Sharma M. Viability kinetics, induction, resuscitation and quantitative real-time polymerase chain reaction analyses of viable but nonculturable Vibrio cholerae O1 in freshwater microcosm. J Appl Microbiol 2012; 112:945-53. [PMID: 22324483 DOI: 10.1111/j.1365-2672.2012.05255.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
AIM To study the induction of a viable but nonculturable (VBNC) state in Vibrio cholerae O1 in freshwater, in response to cold temperatures (4°C) and starvation. METHODS AND RESULTS Vibrio cholerae O1 cells were inoculated in freshwater microcosm and incubated at 4°C. The cells became coccoid, rugose and subsequently nonculturable by day 16 on tryptic soy agar (TSA) and by day 23 on TSA-SP, while 87 and 65% of the cells retained their membrane integrity, respectively. Viable cells were observed until day 30 using direct fluorescent antibody-direct viable count method. In vitro resuscitation was demonstrated by temperature upshift. Utilizing 16S rRNA as an endogenous control, the DNA pol II (27·43-fold), fliG (12·44-fold), ABC transporter (27·11-fold), relA (60·76-fold) and flaC (15·29-fold) were significantly up-regulated in VBNC cells, while the expression of fadL-3 was comparable. The expression of DNA pol II, fliG, ABC transporter, relA and flaC was 3·3, 1·1, 5·9, 5·8 and 1·2-fold, respectively, for resuscitated cells. VBNC cells were found to be virulent, as ctxA and tcpA were expressed. CONCLUSIONS Vibrio cholerae undergoes both phenotypic alteration and genotypic modulation to protect itself from stress in freshwater. SIGNIFICANCE AND IMPACT OF THE STUDY Induction and resuscitation of the VBNC state in freshwater is important for an understanding of the epidemiology of cholera in the freshwater environment.
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Affiliation(s)
- A Mishra
- Department of Medical Microbiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
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Franco SLM, Swenson GJ, Long RA. Year round patchiness of Vibrio vulnificus within a temperate Texas bay. J Appl Microbiol 2012; 112:593-604. [PMID: 22212214 DOI: 10.1111/j.1365-2672.2011.05229.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
AIMS To investigate with high geographical resolution the small-scale spatial and temporal distribution of the pathogen Vibrio vulnificus throughout the water column in a temperate Texas bay where numerous V. vulnificus infections had been reported by the regional media the previous summer. METHODS AND RESULTS Surface and bottom water samples were collected from 19 sites between April 2005 and October 2006 from Matagorda Bay, TX. Physicochemical parameters were measured and V. vulnificus were analysed using quantitative polymerase chain reaction (Q-PCR) as a means of overcoming constraints of traditional culturing techniques. V. vulnificus was detected through out the year, although its temporal and spatial distribution was patchy. V. vulnificus abundances at individual sites ranged from <10 to >1·1×10(3)cellsml(-1) . No statistically reliable predictive model related to the physicochemical parameters could be developed for this pathogen. CONCLUSIONS This study demonstrates that year round detection of V. vulnificus while likely in the viable but nonculturable (VBNC) state during the winter months and emphasizes why physicochemical factors are insufficient metrics for robust regression modelling of this pathogen. SIGNIFICANCE AND IMPACT OF THE STUDY This study provides an effective new tool, Q-PCR, to study environmental distribution of V. vulnificus and that in the light of the patchy distribution observed, new reliable approaches and a mechanistic understanding of pathogen ecology need to be considered to effectively model the aquatic distribution of V. vulnificus.
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Affiliation(s)
- S L M Franco
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Serpaggi V, Remize F, Recorbet G, Gaudot-Dumas E, Sequeira-Le Grand A, Alexandre H. Characterization of the "viable but nonculturable" (VBNC) state in the wine spoilage yeast Brettanomyces. Food Microbiol 2012; 30:438-47. [PMID: 22365358 DOI: 10.1016/j.fm.2011.12.020] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 12/22/2011] [Accepted: 12/23/2011] [Indexed: 11/28/2022]
Abstract
Although the viable but not culturable (VBNC) state has been studied in detail in bacteria, it has been suggested that maintenance of viability with loss of culturability also exists in eukaryotic cells, such as in the wine spoilage yeast Brettanomyces. To provide conclusive evidence for the existence of a VBNC state in this yeast, we investigated its capacity to become viable and nonculturable after sulfite stress, and its ability to recover culturability after stressor removal. Sulfite addition induced loss of culturability but maintenance of viability. Increasing the medium pH to decrease the concentration of toxic SO(2) allowed yeast cells to become culturable again, thus demonstrating the occurrence of a VBNC state in Brettanomyces upon SO(2) exposure. Relative to culturable Brettanomyces, VBNC yeast cells were found to display a 22% decrease in size on the basis of laser granulometry. Assays for 4-ethylguaiacol and 4-ethylphenol, volatile phenols produced by Brettanomyces, indicated that spoilage compound production could persist in VBNC cells. These morphological and physiological changes in VBNC Brettanomyces were coupled to extensive protein pattern modifications, as inferred by comparative two-dimensional electrophoresis and mass spectrometric analyses. Upon identification of 53 proteins out of the 168 spots whose abundance was significantly modified in treated cells relative to control, we propose that the SO(2)-induced VBNC state in Brettanomyces is characterized by a reduced glycolytic flux coupled to changes in redox homeostatis/protein turnover-related processes. This study points out the existence of common mechanisms between yeast and bacteria upon entry to the VBNC state.
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Affiliation(s)
- Virginie Serpaggi
- Institut Universitaire de la Vigne et du Vin Jules Guyot, Université de Bourgogne, Rue Claude Ladrey, BP 27877, F-21078 Dijon Cedex, France
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Sharan R, Chhibber S, Reed RH. Inactivation and sub-lethal injury of salmonella typhi, salmonella typhimurium and vibrio cholerae in copper water storage vessels. BMC Infect Dis 2011; 11:204. [PMID: 21794163 PMCID: PMC3160999 DOI: 10.1186/1471-2334-11-204] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 07/27/2011] [Indexed: 01/11/2023] Open
Abstract
Background This study provides information on the antibacterial effect of copper against the water-borne pathogens Salmonella Typhi, Salmonella Typhimurium and Vibrio cholerae. Methods Suspensions of each pathogen were kept in water within a traditional copper vessel at 30°C for 24 h. Samples were withdrawn, diluted and plated onto suitable growth media. Conventional enumeration of healthy (uninjured) bacteria was carried out using standard aerobic incubation conditions. Additionally, reactive oxygen species-neutralised (ROS-n) conditions were achieved by adding the peroxide scavenger sodium pyruvate to the medium with anaerobic incubation, to enumerate uninjured (ROS-insensitive) and injured (ROS-sensitive) bacteria. Differences between log-transformed means of conventional (aerobic) and ROS-n counts were statistically evaluated using t tests. Results Overall, all three pathogens were inactivated by storage in copper vessels for 24 h. However, for shorter-term incubation (4-12 h), higher counts were observed under ROS-n conditions than under aerobic conditions, which demonstrate the presence of substantial numbers of sub-lethally injured cells prior to their complete inactivation. Conclusions The present study has for the first time confirmed that these bacterial pathogens are inactivated by storage in a copper vessel within 24 h. However, it has also demonstrated that it is necessary to account for short-term sub-lethal injury, manifest as ROS-sensitivity, in order to more fully understand the process. This has important practical implications in terms of the time required to store water within a copper vessel to completely inactivate these bacteria and thereby remove the risk of water-borne disease transmission by this route.
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Affiliation(s)
- Riti Sharan
- Centre for Plant and Water Science, Faculty of Sciences, Engineering and Health, CQUniversity, Rockhampton, Queensland 4702, Australia
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Ye M, Huang Y, Neetoo H, Shearer AEH, Chen H. Influence of growth conditions on pressure resistance of Vibrio parahaemolyticus in oysters and the optimization of postpressure treatment recovery conditions. J Food Prot 2011; 74:751-8. [PMID: 21549045 DOI: 10.4315/0362-028x.jfp-10-521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Vibrio parahaemolyticus ATCC 43996 was grown at 15°C for 53 h, 20°C for 24 h, 25°C for 12 h, 30°C for 9 h, 35°C for 9 h, or 40°C for 6 h to early stationary phase. Oyster meats were blended, autoclaved at 121°C for 15 min, inoculated with V. parahaemolyticus, and pressure treated at 250 MPa for 2 and 3 min and at 300 MPa for 1 and 2 min at 21°C. Overall, growth temperatures of 20 and 40°C yielded the greatest pressure resistance in V. parahaemolyticus. The effects of salt concentration and H(2)O(2)-degrading compounds on the recovery of V. parahaemolyticus also were investigated. Sterile oyster meats were inoculated with V. parahaemolyticus and treated at 250 MPa for 1, 2, or 3 min at 21°C. These meats were then blended with 0.1% peptone water supplemented with 0.5 to 1.5% NaCl and plated on tryptic soy agar (TSA) supplemented with 0 to 3.5% NaCl. For recovery of pressure-injured cells, peptone water with 1% NaCl and TSA with 0.5% NaCl were the best diluent and plating medium, respectively. Addition of sodium pyruvate (0.05 to 0.2%) or catalase (8 to 32 U/ml) did not increase the recovery of V. parahaemolyticus after pressure treatment. The effect of incubation temperature and gas atmosphere on the recovery of V. parahaemolyticus after pressure treatment also was determined. Aerobic incubation at 30°C resulted in the highest recovery of V. parahaemolyticus in sterile oyster meats. The 30°C incubation temperature was also the optimum temperature for recovery of V. parahaemolyticus in pressure-treated live oysters. The results of this study indicate that the growth conditions for V. parahaemolyticus before and after high hydrostatic pressure treatment should be taken into consideration when assessing the efficacy of pressure inactivation.
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Affiliation(s)
- Mu Ye
- Department of Animal and Food Sciences, University of Delaware, Newark, Delaware 19716-2150, USA
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Pinto D, Almeida V, Almeida Santos M, Chambel L. Resuscitation of Escherichia coli VBNC cells depends on a variety of environmental or chemical stimuli. J Appl Microbiol 2011; 110:1601-11. [DOI: 10.1111/j.1365-2672.2011.05016.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Pawlowski DR, Metzger DJ, Raslawsky A, Howlett A, Siebert G, Karalus RJ, Garrett S, Whitehouse CA. Entry of Yersinia pestis into the viable but nonculturable state in a low-temperature tap water microcosm. PLoS One 2011; 6:e17585. [PMID: 21436885 PMCID: PMC3059211 DOI: 10.1371/journal.pone.0017585] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 01/24/2011] [Indexed: 01/14/2023] Open
Abstract
Yersinia pestis, the causative agent of plague, has caused several pandemics throughout history and remains endemic in the rodent populations of the western United States. More recently, Y. pestis is one of several bacterial pathogens considered to be a potential agent of bioterrorism. Thus, elucidating potential mechanisms of survival and persistence in the environment would be important in the event of an intentional release of the organism. One such mechanism is entry into the viable but non-culturable (VBNC) state, as has been demonstrated for several other bacterial pathogens. In this study, we showed that Y. pestis became nonculturable by normal laboratory methods after 21 days in a low-temperature tap water microcosm. We further show evidence that, after the loss of culturability, the cells remained viable by using a variety of criteria, including cellular membrane integrity, uptake and incorporation of radiolabeled amino acids, and protection of genomic DNA from DNase I digestion. Additionally, we identified morphological and ultrastructural characteristics of Y. pestis VBNC cells, such as cell rounding and large periplasmic spaces, by electron microscopy, which are consistent with entry into the VBNC state in other bacteria. Finally, we demonstrated resuscitation of a small number of the non-culturable cells. This study provides compelling evidence that Y. pestis persists in a low-temperature tap water microcosm in a viable state yet is unable to be cultured under normal laboratory conditions, which may prove useful in risk assessment and remediation efforts, particularly in the event of an intentional release of this organism.
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The cell membrane as a major site of damage during aerosolization of Escherichia coli. Appl Environ Microbiol 2010; 77:920-5. [PMID: 21148696 DOI: 10.1128/aem.01116-10] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
This study aimed to provide data on the survival and site of damage of Escherichia coli cells following aerosolization using two different techniques, nebulization and flow focusing. Four metabolic stains were assessed for their ability to detect respiratory activities and membrane homeostasis in aerosolized E. coli cells. The degree of sublethal injury increased significantly over the 10-min period of aerosolization in E. coli cells aerosolized by using the Collison nebulizer, reaching up to 99.9% of the population. In contrast, a significantly lower proportion of the population was sublethally damaged during aerosolization using the flow-focusing aerosol generator (FFAG). Concomitantly, loss of membrane homeostasis increased at a higher rate in nebulized cells (68 to 71%) than in those aerosolized by using the FFAG (32 to 34%). The activities of respiratory enzymes decreased at increased rates in nebulized cells (27 to 37%) compared to the rates of decrease in cells aerosolized by using the FFAG (59 to 61%). The results indicate that the physiology of an aerosolized bacterium is linked to the method of aerosol generation and may affect the interpretation of a range of aerobiological phenomenon.
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Masmoudi S, Denis M, Maalej S. Inactivation of the gene katA or sodA affects the transient entry into the viable but non-culturable response of Staphylococcus aureus in natural seawater at low temperature. MARINE POLLUTION BULLETIN 2010; 60:2209-2214. [PMID: 20833402 DOI: 10.1016/j.marpolbul.2010.08.017] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 08/06/2010] [Accepted: 08/19/2010] [Indexed: 05/29/2023]
Abstract
We have investigated the fate of Staphylococcus aureus by starving the cells and maintaining them in natural seawater at 22 and 4 °C. At 22 °C, cells developed a long-term survival state where about 0.037% of the initial population remained culturable over more than 7 months, whereas at 4 °C, bacteria lost culturability and transiently entered into the viable but non-culturable state (VBNC). However, after 22 days of entry into the VBNC state, the number of viable cells detected via the direct viable count method decreased significantly. We show here that mutational inactivation of catalase (KatA) or superoxide dismutase (SodA) rendered strains hypersensitive to seawater stress at 4 °C and consequently, part of the seawater lethality on S. aureus at low temperature is mediated by reactive oxygen species (ROS) during microcosm-survival process. Shifting the temperature from 4 to 22 °C of totally non-culturable wild-type cells induced a partial recovery of the population. However, deficiencies in catalase or superoxide dismutase prevent resuscitation ability.
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Affiliation(s)
- Salma Masmoudi
- Laboratoire de Microbiologie, Faculté des Sciences de Sfax, B.P. 1171, 3000 Sfax, Tunisia
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Nakashima T, Seki T, Matsumoto A, Miura H, Sato E, Niwano Y, Kohno M, Ōmura S, Takahashi Y. Generation of reactive oxygen species from conventional laboratory media. J Biosci Bioeng 2010; 110:304-7. [DOI: 10.1016/j.jbiosc.2010.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 03/05/2010] [Accepted: 03/08/2010] [Indexed: 11/16/2022]
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Chihib NE, Mary P, Federighi M, Hornez JP. The effect of preculture conditions on the culturability and viability of Aeromonas hydrophila when exposed to oligotrophic and cold stresses. World J Microbiol Biotechnol 2010. [DOI: 10.1007/s11274-010-0473-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Jallouli W, Zouari N, Jaoua S. Involvement of oxidative stress and growth at high cell density in the viable but nonculturable state of Photorhabdus temperata ssp. temperata strain K122. Process Biochem 2010. [DOI: 10.1016/j.procbio.2010.01.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Limthammahisorn S, Brady YJ, Arias CR. In vivo gene expression of cold shock and other stress-related genes in Vibrio vulnificus during shellstock temperature control conditions in oysters. J Appl Microbiol 2010; 106:642-50. [PMID: 19200328 DOI: 10.1111/j.1365-2672.2008.04038.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS To determine Vibrio vulnificus response to shellstock refrigeration conditions while the bacterium was embedded in oysters (in vivo). METHODS AND RESULTS Depurated oysters were artificially inoculated with V. vulnificus. Several cold-shock conditions were examined according to the National Sanitation Shellfish Program guidelines. Culturability of cells along the refrigeration period was measured using specific colony dot-blot. Gene expression of putative cold-shock genes (csp1, csp3, csp4 and csp5) as well as three stress-related genes (rpoS, oxyR and katG) was determined by reverse transcriptase polymerase chain reaction. Vibrio vulnificus exhibited a decline in cell viability after cold shock but a cold adaptation response was observed when oysters were kept at suboptimal (15 degrees C) temperatures. 16SrRNA, and rpoS genes were constitutively expressed while expression of csp genes varied among strains and time points. CONCLUSIONS Vibrio vulnificus culturability was reduced after oysters were subjected to shellstock refrigeration conditions. When V. vulnificus was allowed to acclimate to cold temperatures, its survival after cold shock was higher. None of the cold shock genes analysed behaved as csp type I genes. SIGNIFICANCE AND IMPACT OF THE STUDY A model for artificially inoculated specific strains of V. vulnificus into oysters has been established. For the first time, V. vulnficus gene expression was assessed with the pathogen embedded in oysters.
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Affiliation(s)
- S Limthammahisorn
- Department of Fisheries and Allied Aquacultures, Auburn University, Auburn, AL, USA
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Mulyukin AL, Demkina EV, Kryazhevskikh NA, Suzina NE, Vorob’eva LI, Duda VI, Galchenko VF, El-Registan GI. Dormant forms of Micrococcus luteus and Arthrobacter globiformis not platable on standard media. Microbiology (Reading) 2009. [DOI: 10.1134/s0026261709040031] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Burnham V, Janes M, Jakus L, Supan J, DePaola A, Bell J. Growth and Survival Differences of Vibrio vulnificus and Vibrio parahaemolyticus Strains during Cold Storage. J Food Sci 2009; 74:M314-8. [DOI: 10.1111/j.1750-3841.2009.01227.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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