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Zhang X, Zhou D, Bai H, Liu Q, Xiao XL, Yu YG. Comparative transcriptome analysis of virulence genes of enterohemorrhagic Escherichia coli O157:H7 to acid stress. FOOD BIOTECHNOL 2021. [DOI: 10.1080/08905436.2021.1908345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xiaowei Zhang
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Donggen Zhou
- Ningbo International Travel Healthcare Center, Ningbo City, Haishu District, China
| | - Hong Bai
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Qijun Liu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Xing-Long Xiao
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
| | - Yi-Gang Yu
- School of Food Science and Engineering, South China University of Technology, Guangzhou City, Guangdong Province, China
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2
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Zheng Z, Xie Y, Ma S, Tu J, Li J, Liang S, Xu Y, Shi C. Effect of 405-nm light-emitting diode on environmental tolerance of Cronobacter sakazakii in powdered infant formula. Food Res Int 2021; 144:110343. [PMID: 34053539 DOI: 10.1016/j.foodres.2021.110343] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 02/05/2023]
Abstract
Cronobacter sakazakii is an opportunistic pathogen that can survive extreme desiccation, heat, acid, and osmotic stress. This can increase the risk of infection, resulting in severe diseases, mainly in neonates. The inactivation effect of 405 ± 5-nm light-emitting diode (LED) illumination on C. sakazakii with different initial concentrations and C. sakazakii strains isolated from powdered infant formula (PIF) and baby rice cereal (BRC) were firstly evaluated. Then, the effect of 405 ± 5-nm LED on the tolerance of diverse environmental conditions of C. sakazakii in PIF was investigated. Conditions involving desiccation [PIF, Water activity (aw): 0.2-0.5], heat (45, 50, and 55 °C), acid (simulated gastric fluid: SGF, pH 4.75 ± 0.25), and bile salt (0.2%, bile salt solution) were used to study the effects of 405-nm LED on C. sakazakii resistance. The transcription levels of ten tolerance-associated genes and changes in bacterial cell membrane were examined to understand the response of C. sakazakii to LED illumination. The results showed that 405-nm LED effectively inactivated C. sakazakii ATCC 29544 with initial concentration from 8 to 1 log CFU/g in PIF and strains isolated from PIF and BRC. Moreover, 405-nm LED could decrease the tolerance of C. sakazakii in PIF to desiccation, heat treatment at 50 and 55 °C, SGF, and bile salt to different degrees, but the resistance to the heat treatment at 45 °C was not influenced by LED illumination. In addition, the transcription levels of the ten tolerance-associated genes measured in the LED-illuminated C. sakazakii cells were significantly downregulated compared with those in unilluminated controls. The damage on cell membrane was confirmed for LED-treated cells by LIVE/DEAD® assay. These results indicate that 405-nm LED illumination may be effective at reducing the environmental resistance of C. sakazakii in PIF. Furthermore, this study suggests the potential for applying 405-nm LED technology in the prevention and control of pathogens in food processing, production, and storage environments.
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Affiliation(s)
- Zhanwen Zheng
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yawen Xie
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Sheng Ma
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Junhong Tu
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiahui Li
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Sen Liang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology and Business University, Beijing 100048, China
| | - Yunfeng Xu
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, Henan 471023, China
| | - Chao Shi
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China.
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3
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Uriot O, Chalancon S, Mazal C, Etienne-Mesmin L, Denis S, Blanquet-Diot S. Use of the Dynamic TIM-1 Model for an In-Depth Understanding of the Survival and Virulence Gene Expression of Shiga Toxin-Producing Escherichia coli in the Human Stomach and Small Intestine. Methods Mol Biol 2021; 2291:297-315. [PMID: 33704760 DOI: 10.1007/978-1-0716-1339-9_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Due to obvious ethical and technical reasons, it remains very difficult to evaluate the survival and expression of virulence genes of food-borne pathogens, such as Shiga toxin-producing Escherichia coli (STEC) in the human gastrointestinal tract. Here, we describe the use of the dynamic TNO (Toegepast Natuurwetenschappelijk Onderzoek) gastrointestinal model (TIM-1) as a powerful in vitro tool to obtain the kinetics of STEC survival by plate counting, the regulation of major virulence genes by RT-qPCR, and the production of Shiga toxins by ELISA, in the human stomach and small intestine. The gut model was adapted in order that in vitro digestions were performed both under adult and child digestive conditions, specific at risk populations for STEC infections.
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Affiliation(s)
- Ophélie Uriot
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Sandrine Chalancon
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Carine Mazal
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Lucie Etienne-Mesmin
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Sylvain Denis
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France
| | - Stéphanie Blanquet-Diot
- Microbiology Digestive Environment and Health, UMR UCA-INRA 454 MEDIS, Université Clermont Auvergne, Clermont-Ferrand, France.
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4
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Yu L, Ji S, Yu J, Fu W, Zhang L, Li J, Gao F, Jiang Y. Effects of lactic acid stress with lactic acid adaptation on the survival and expression of virulence‐related genes inEscherichia coliO157:H7. J Food Saf 2019. [DOI: 10.1111/jfs.12701] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Lanlin Yu
- College of Animal Science and TechnologyNanjing Agricultural University Nanjing China
- Jiangsu Key Laboratory of Animal Origin Food Production and Safety GuaranteeNanjing Agricultural University Nanjing China
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety ControlNanjing Agricultural University Nanjing China
| | - Saisai Ji
- School of Food Science and Pharmaceutical EngineeringNanjing Normal University Nanjing China
| | - Jinlong Yu
- School of Food Science and Pharmaceutical EngineeringNanjing Normal University Nanjing China
| | - Wenjing Fu
- School of Food Science and Pharmaceutical EngineeringNanjing Normal University Nanjing China
| | - Lin Zhang
- College of Animal Science and TechnologyNanjing Agricultural University Nanjing China
- Jiangsu Key Laboratory of Animal Origin Food Production and Safety GuaranteeNanjing Agricultural University Nanjing China
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety ControlNanjing Agricultural University Nanjing China
| | - Jiaolong Li
- College of Animal Science and TechnologyNanjing Agricultural University Nanjing China
- Jiangsu Key Laboratory of Animal Origin Food Production and Safety GuaranteeNanjing Agricultural University Nanjing China
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety ControlNanjing Agricultural University Nanjing China
| | - Feng Gao
- College of Animal Science and TechnologyNanjing Agricultural University Nanjing China
- Jiangsu Key Laboratory of Animal Origin Food Production and Safety GuaranteeNanjing Agricultural University Nanjing China
- Jiangsu Collaborative Innovation Center of Meat Production and Processing, Quality and Safety ControlNanjing Agricultural University Nanjing China
| | - Yun Jiang
- School of Food Science and Pharmaceutical EngineeringNanjing Normal University Nanjing China
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Zhou M, Ding X, Ma F, Xu Y, Zhang J, Zhu G, Lu Y. Long polar fimbriae contribute to pathogenic Escherichia coli infection to host cells. Appl Microbiol Biotechnol 2019; 103:7317-7324. [PMID: 31359104 DOI: 10.1007/s00253-019-10014-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 07/07/2019] [Accepted: 07/11/2019] [Indexed: 01/01/2023]
Abstract
Long polar fimbria (LPF) is one of the few fimbrial adhesins of enterohemorrhagic Escherichia coli (E. coli) O157:H7 associated with colonization on host intestine, and both two types of LPF (including LPF1 and LPF2) play essential roles during the bacterial infection process. Though the fimbriae had been well studied in intestinal pathogenic E. coli strains, new evidences from our research revealed that it might be the key virulence for bovine mastitis pathogenic E. coli (MPEC) as well. This article summarizes the current knowledge on the LPF in E. coli, focusing on its genetic characteristics, prevalence, expression regulation, and adherence mechanism in different pathotypes of E. coli strains.
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Affiliation(s)
- Mingxu Zhou
- Institute of Veterinary Immunology &Engineering, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, 210014, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, China
| | - Xueyan Ding
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, China.,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, 50 Zhongling Street, Nanjing, 210014, China
| | - Fang Ma
- Institute of Veterinary Immunology &Engineering, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, 210014, China
| | - Yue Xu
- Institute of Veterinary Immunology &Engineering, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, 210014, China
| | - Jinqiu Zhang
- Institute of Veterinary Immunology &Engineering, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, 210014, China
| | - Guoqiang Zhu
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, College of Veterinary Medicine, Yangzhou University, 12 East Wenhui Road, Yangzhou, 225009, China. .,Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, 50 Zhongling Street, Nanjing, 210014, China.
| | - Yu Lu
- Institute of Veterinary Immunology &Engineering, Jiangsu Academy of Agricultural Sciences, 50 Zhongling Street, Nanjing, 210014, China.
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Haiwen Z, Rui H, Bingxi Z, Qingfeng G, Jifeng Z, Xuemei W, Beibei W. Oral Administration of Bovine Lactoferrin-Derived Lactoferricin (Lfcin) B Could Attenuate Enterohemorrhagic Escherichia coli O157:H7 Induced Intestinal Disease through Improving Intestinal Barrier Function and Microbiota. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:3932-3945. [PMID: 30892034 DOI: 10.1021/acs.jafc.9b00861] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lactoferricin (Lfcin) B, derived from lactoferrin in whey, has attracted considerable attention because of its multiple biological functions. Zoonotic enterohemorrhagic Escherichia coli (EHEC) O157:H7 has adverse effects on intestinal epithelial barrier function, leading to serious intestinal disease. In this study, the EHEC O157:H7-induced intestinal dysfunction model was developed to investigate the effects of Lfcin B on EHEC O157:H7-induced epithelial barrier disruption and microbiota dysbiosis. Results showed that the inflammatory infiltration indexes in the jejunum of Lfcin B-treated animals were significantly decreased. Lfcin B administration also significantly improved ZO-1 and occludin expression following O157:H7-induced injury. Finally, microbiota analysis of the cecal samples revealed that Lfcin B inhibited the O157:H7-induced abnormal increase in Bacteroides. Therefore, Lfcin B efficiently attenuated O157:H7-induced epithelial barrier damage and dysregulation of inflammation status, while maintaining microbiota homeostasis in the intestine, indicating that it may be an excellent food source for prevention and therapy of EHEC O157:H7-related intestinal dysfunction.
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Affiliation(s)
- Zhang Haiwen
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
- Key Laboratory of Tropical Biological Resources of Ministry of Education , Haikou , Hainan 570228 , People's Republic of China
| | - Hua Rui
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Zhang Bingxi
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
| | - Guan Qingfeng
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
- Key Laboratory of Tropical Biological Resources of Ministry of Education , Haikou , Hainan 570228 , People's Republic of China
| | - Zeng Jifeng
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
- Key Laboratory of Tropical Biological Resources of Ministry of Education , Haikou , Hainan 570228 , People's Republic of China
| | - Wang Xuemei
- Key Laboratory of Tropical Animal Breeding and Epidemic Disease Research of Hainan Province , Hainan University , Haikou , Hainan 570228 , People's Republic of China
- Key Laboratory of Tropical Biological Resources of Ministry of Education , Haikou , Hainan 570228 , People's Republic of China
| | - Wang Beibei
- Key Laboratory of Tropical Biological Resources of Ministry of Education , Haikou , Hainan 570228 , People's Republic of China
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7
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Enterohemorrhagic Escherichia coli pathogenesis: role of Long polar fimbriae in Peyer's patches interactions. Sci Rep 2017; 7:44655. [PMID: 28317910 PMCID: PMC5357955 DOI: 10.1038/srep44655] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/13/2017] [Indexed: 11/14/2022] Open
Abstract
Enterohemorrhagic Escherichia coli (EHEC) are major food-borne pathogens whose survival and virulence in the human digestive tract remain unclear owing to paucity of relevant models. EHEC interact with the follicle-associated epithelium of Peyer’s patches of the distal ileum and translocate across the intestinal epithelium via M-cells, but the underlying molecular mechanisms are still unknown. Here, we investigated the involvement of Long polar fimbriae (Lpf) in EHEC pathogenesis. Of the 236 strains tested, a significant association was observed between the presence of lpf operons and pathogenicity. In sophisticated in vitro models of the human gastro-intestinal tract, lpf expression was induced during transit through the simulated stomach and small intestine, but not in the colonic compartment. To investigate the involvement of Lpf in EHEC pathogenesis, lpf isogenic mutants and their relative trans-complemented strains were generated. Translocation across M-cells, interactions with murine ileal biopsies containing Peyer’s patches and the number of hemorrhagic lesions were significantly reduced with the lpf mutants compared to the wild-type strain. Complementation of lpf mutants fully restored the wild-type phenotypes. Our results indicate that (i) EHEC might colonize the terminal ileum at the early stages of infection, (ii) Lpf are an important player in the interactions with Peyer’s patches and M-cells, and could contribute to intestinal colonization.
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Roussel C, Cordonnier C, Galia W, Le Goff O, Thévenot J, Chalancon S, Alric M, Thevenot-Sergentet D, Leriche F, Van de Wiele T, Livrelli V, Blanquet-Diot S. Increased EHEC survival and virulence gene expression indicate an enhanced pathogenicity upon simulated pediatric gastrointestinal conditions. Pediatr Res 2016; 80:734-743. [PMID: 27429202 DOI: 10.1038/pr.2016.144] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/15/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND Enterohemorrhagic Escherichia coli (EHEC) are major foodborne pathogens that constitute a serious public health threat, mainly in young children. Shiga toxins (Stx) are the main virulence determinants of EHEC pathogenesis but adhesins like intimin (eae) and Long polar fimbriae (Lpf) also contribute to infection. The TNO GastroIntestinal Model (TIM) was used for a comparative study of EHEC O157:H7 survival and virulence under adult and child digestive conditions. METHODS Survival kinetics in the in vitro digestive tract were determined by plating while bacterial viability was assessed by flow cytometry analysis. Expression of stx, eae, and lpf genes was followed by reverse transcriptase-quantitative PCR (RT-qPCR) and Stx production was measured by ELISA (enzyme-linked immunosorbent assay). RESULTS Upon gastrointestinal passage, a higher amount of viable cells was found in the simulated ileal effluents of children compared to that of adults (with 34 and 6% of viable cells, respectively). Expression levels of virulence genes were up to 125-fold higher in children. Stx was detected only in child ileal effluents. CONCLUSION Differences in digestive physicochemical parameters may partially explain why children are more susceptible to EHEC infection than adults. Such data are essential for a full understanding of EHEC pathogenesis and would help in designing novel therapeutic approaches.
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Affiliation(s)
- Charlène Roussel
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Charlotte Cordonnier
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France
| | - Wessam Galia
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.,Unité CALYTISS, VetAgro Sup, Lempdes, France
| | - Olivier Le Goff
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Jonathan Thévenot
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France.,M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France
| | - Sandrine Chalancon
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Monique Alric
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
| | - Delphine Thevenot-Sergentet
- UMR 5557 Ecologie Microbienne, Research Group on Bacterial Opportunistic Pathogens and Environment, CNRS, VetAgro Sup and Université de Lyon, Lyon, France.,Laboratoire d'Etude des Microorganismes Alimentaires Pathogènes, French National Reference Laboratory for Escherichia coli including Shiga Toxin-Producing E. coli, VetAgro Sup, Université de Lyon, Marcy l'Etoile, France
| | | | - Tom Van de Wiele
- CMet, Center for Microbial Ecology and Technology, Ghent University, Ghent, Belgium
| | - Valérie Livrelli
- M2iSH, Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte UMR INSERM/Université d'Auvergne, Université d'Auvergne, Clermont-Ferrand, France.,Service de Bactériologie, CHU de Clermont-Ferrand, Clermont-Ferrand, France
| | - Stéphanie Blanquet-Diot
- EA 4678 CIDAM, Conception Ingénierie et Développement de l'Aliment et du Médicament, Université d'Auvergne, Clermont-Ferrand, France
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Effect of Temperature on Fimbrial Gene Expression and Adherence of Enteroaggregative Escherichia coli. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015. [PMID: 26213951 PMCID: PMC4555238 DOI: 10.3390/ijerph120808631] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The influence of temperature on bacterial virulence has been studied worldwide from the viewpoint of climate change and global warming. The bacterium enteroaggregative Escherichia coli (EAEC) is the causative agent of watery diarrhea and shows an increasing incidence worldwide. Its pathogenicity is associated with the virulence factors aggregative adherence fimbria type I and II (AAFI and AAFII), encoded by aggA and aafA in EAEC strains 17-2 and 042, respectively. This study focused on the effect of temperature increases from 29 °C to 40 °C on fimbrial gene expression using real-time PCR, and on its virulence using an aggregative adherence assay and biofilm formation assay. Incubation at 32 °C caused an up-regulation in both EAEC strains 17-2 and strain 042 virulence gene expression. EAEC strain 042 cultured at temperature above 32 °C showed down-regulation of aafA expression except at 38 °C. Interestingly, EAEC cultured at a high temperature showed a reduced adherence to cells and an uneven biofilm formation. These results provide evidence that increases in temperature potentially affect the virulence of pathogenic EAEC, although the response varies in each strain.
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Yang G, Wang L, Wang Y, Li P, Zhu J, Qiu S, Hao R, Wu Z, Li W, Song H. hfq regulates acid tolerance and virulence by responding to acid stress in Shigella flexneri. Res Microbiol 2015; 166:476-85. [DOI: 10.1016/j.resmic.2015.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 06/13/2015] [Accepted: 06/17/2015] [Indexed: 11/28/2022]
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11
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Alteration of the Microbiota and Virulence Gene Expression in E. coli O157:H7 in Pig Ligated Intestine with and without AE Lesions. PLoS One 2015; 10:e0130272. [PMID: 26090813 PMCID: PMC4474639 DOI: 10.1371/journal.pone.0130272] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 05/19/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Previously we found that E. coli O157:H7 inoculated into ligated pig intestine formed attaching and effacing (AE) lesions in some pigs but not in others. The present study evaluated changes in the microbial community and in virulence gene expression in E. coli O157:H7 in ligated pig intestine in which the bacteria formed AE lesions or failed to form AE lesions. METHODOLOGY/PRINCIPAL FINDINGS The intestinal microbiota was assessed by RNA-based denaturing gradient gel electrophoresis (DGGE) analysis. The DGGE banding patterns showed distinct differences involving two bands which had increased intensity specifically in AE-negative pigs (AE- bands) and several bands which were more abundant in AE-positive pigs. Sequence analysis revealed that the two AE- bands belonged to Veillonella caviae, a species with probiotic properties, and Bacteroides sp. Concurrent with the differences in microbiota, gene expression analysis by quantitative PCR showed that, compared with AE negative pigs, E. coli O157:H7 in AE positive pigs had upregulated genes for putative adhesins, non-LEE encoded nleA and quorum sensing qseF, acid resistance gene ureD, and genes from the locus of enterocyte effacement (LEE). CONCLUSIONS/SIGNIFICANCE The present study demonstrated that AE-positive pigs had reduced activities or populations of Veillonella caviae and Bacterioides sp. compared with AE-negative pigs. Further studies are required to understand how the microbiota was changed and the role of these organisms in the control of E. coli O157:H7.
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12
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Arenas-Hernández MM, Rojas-López M, Medrano-López A, Nuñez-Reza KJ, Puente JL, Martínez-Laguna Y, Torres AG. Environmental regulation of the long polar fimbriae 2 of enterohemorrhagic Escherichia coli O157:H7. FEMS Microbiol Lett 2014; 357:105-14. [PMID: 24966050 DOI: 10.1111/1574-6968.12513] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Revised: 06/12/2014] [Accepted: 06/13/2014] [Indexed: 11/27/2022] Open
Abstract
The molecular mechanisms controlling expression of the long polar fimbriae 2 (Lpf2) of enterohemorrhagic Escherichia coli (EHEC) O157:H7 were evaluated. Primer extension was used to locate the lpfA2 transcriptional start site in EHEC strain EDL933 at 171 bp upstream of the lpfA2 start codon. Semi-quantitative RT-PCR demonstrated that the highest lpfA2 expression occurs between an OD600 of 1.0 and 1.2 in DMEM at pH 6.5 and 37 °C. The level of lpfA2 transcription at OD600 1.2 and pH 6.5 was four times greater than that at pH 7.2. Although lpfA2 expression was decreased under iron-depleted conditions, its expression was increased in a ferric-uptake-regulator (Fur) mutant strain. The lpfA2 transcript was 0.7 and 2 times more abundant in wt EHEC grown in DMEM pH 6.5 plus iron and MacConkey broth at 25 °C, respectively, than in DMEM at pH 6.5. The lpf2 expression in DMEM pH 6.5 plus iron and bile salts was 2.7 times more abundant than baseline conditions. Further, transcription in the EDL933∆fur was 0.6 and 0.8 times higher as compared with the wt strain grown in DMEM pH 6.5 plus iron and MacConkey broth, respectively. Electrophoretic mobility shift assays showed that purified Fur interacts with the lpf2 regulatory region, indicating that Fur repression is exerted by direct binding to the promoter region. In summary, we demonstrated that the EHEC lpf2 operon is regulated in response to temperature, pH, bile salts and iron, during the exponential phase of growth, and is controlled by Fur.
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Affiliation(s)
- Margarita M Arenas-Hernández
- Posgrado en Microbiología, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico; Licenciatura en Biomedicina, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico; Centro de Investigaciones en Ciencias Microbiológicas, Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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Yin X, Zhou H, Gong J. Effects of culture conditions and tomato, spinach and lettuce lysates on adherence to intestinal epithelial cells of Salmonella Typhimurium PT 193. Food Res Int 2013. [DOI: 10.1016/j.foodres.2012.10.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Klitgaard K, Friis C, Jensen TK, Angen Ø, Boye M. Transcriptional portrait of Actinobacillus pleuropneumoniae during acute disease--potential strategies for survival and persistence in the host. PLoS One 2012; 7:e35549. [PMID: 22530048 PMCID: PMC3328466 DOI: 10.1371/journal.pone.0035549] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/21/2012] [Indexed: 11/24/2022] Open
Abstract
Background Gene expression profiles of bacteria in their natural hosts can provide novel insight into the host-pathogen interactions and molecular determinants of bacterial infections. In the present study, the transcriptional profile of the porcine lung pathogen Actinobacillus pleuropneumoniae was monitored during the acute phase of infection in its natural host. Methodology/Principal Findings Bacterial expression profiles of A. pleuropneumoniae isolated from lung lesions of 25 infected pigs were compared in samples taken 6, 12, 24 and 48 hours post experimental challenge. Within 6 hours, focal, fibrino hemorrhagic lesions could be observed in the pig lungs, indicating that A. pleuropneumoniae had managed to establish itself successfully in the host. We identified 237 differentially regulated genes likely to encode functions required by the bacteria for colonization and survival in the host. This group was dominated by genes involved in various aspects of energy metabolism, especially anaerobic respiration and carbohydrate metabolism. Remodeling of the bacterial envelope and modifications of posttranslational processing of proteins also appeared to be of importance during early infection. The results suggested that A. pleuropneumoniae is using various strategies to increase its fitness, such as applying Na+ pumps as an alternative way of gaining energy. Furthermore, the transcriptional data provided potential clues as to how A. pleuropneumoniae is able to circumvent host immune factors and survive within the hostile environment of host macrophages. This persistence within macrophages may be related to urease activity, mobilization of various stress responses and active evasion of the host defenses by cell surface sialylation. Conclusions/Significance The data presented here highlight the importance of metabolic adjustments to host conditions as virulence factors of infecting microorganisms and help to provide insight into the mechanisms behind the efficient colonization and persistence of A. pleuropneumoniae during acute disease.
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Affiliation(s)
- Kirstine Klitgaard
- National Veterinary Institute, Technical University of Denmark, Frederiksberg C, Denmark.
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