1
|
Zhang T, Yang Y, Zeng X, Wu Z, Pan D, Luo H, Tao M, Guo Y. Protective mechanism of milk fat globule membrane proteins on Lactobacillus acidophilus CICC 6074 under acid stress based on proteomic analysis. Food Chem 2024; 434:137297. [PMID: 37741242 DOI: 10.1016/j.foodchem.2023.137297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 08/18/2023] [Accepted: 08/24/2023] [Indexed: 09/25/2023]
Abstract
The prerequisite for lactic acid bacteria to perform their probiotic function is that they could survive the acid-stressed environment of production and application. In this experiment, the protective mechanism of milk fat globule membrane (MFGM) proteins on lactic acid bacteria under acid stress was investigated. Scanning electron microscopy and fluorescence probe were used to analyze the condition of the acid-treated bacteria, which showed that MFGM proteins could enhance the survival ability of Lactobacillus acidophilus CICC 6074 under acid stress by maintaining cell morphology, elevating intracellular pH and H+-ATPase activity. Furthermore, Tandem Mass Tags (TMT) proteomic analysis revealed that MFGM protein could exert protective effects on L. acidophilus CICC 6074 by regulating amino acid metabolism, ATPase activity, peptidoglycan synthesis, gene repair and heritage, etc. The results will provide a new approach for the protection and development of functional lactic acid bacteria.
Collapse
Affiliation(s)
- Tao Zhang
- Department of Food Science and Technology, School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, Jiangsu, PR China; State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, Zhejiang, PR China
| | - Yujie Yang
- Department of Food Science and Technology, School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, Jiangsu, PR China
| | - Xiaoqun Zeng
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, Zhejiang, PR China
| | - Zhen Wu
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, Zhejiang, PR China
| | - Daodong Pan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, Zhejiang, PR China
| | - Haibo Luo
- Department of Food Science and Technology, School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, Jiangsu, PR China
| | - Mingxuan Tao
- Department of Food Science and Technology, School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, Jiangsu, PR China
| | - Yuxing Guo
- Department of Food Science and Technology, School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, Jiangsu, PR China.
| |
Collapse
|
2
|
Pilliol V, Morsli M, Terlier L, Hassani Y, Malat I, Guindo CO, Davoust B, Lamglait B, Drancourt M, Aboudharam G, Grine G, Terrer E. Candidatus Methanosphaera massiliense sp. nov., a methanogenic archaeal species found in a human fecal sample and prevalent in pigs and red kangaroos. Microbiol Spectr 2024; 12:e0514122. [PMID: 38189277 PMCID: PMC10845953 DOI: 10.1128/spectrum.05141-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 11/24/2023] [Indexed: 01/09/2024] Open
Abstract
Methanosphaera stadtmanae was the sole Methanosphaera representative to be cultured and detected by molecular methods in the human gut microbiota, further associated with digestive and respiratory diseases, leaving unknown the actual diversity of human-associated Methanosphaera species. Here, a novel Methanosphaera species, Candidatus Methanosphaera massiliense (Ca. M. massiliense) sp. nov. was isolated by culture using a hydrogen- and carbon dioxide-free medium from one human feces sample. Ca. M. massiliense is a non-motile, 850 nm Gram-positive coccus autofluorescent at 420 nm. Whole-genome sequencing yielded a 29.7% GC content, gapless 1,785,773 bp genome sequence with an 84.5% coding ratio, encoding for alcohol and aldehyde dehydrogenases promoting the growth of Ca. M. massiliense without hydrogen. Screening additional mammal and human feces using a specific genome sequence-derived DNA-polymerase RT-PCR system yielded a prevalence of 22% in pigs, 12% in red kangaroos, and no detection in 149 other human samples. This study, extending the diversity of Methanosphaera in human microbiota, questions the zoonotic sources of Ca. M. massiliense and possible transfer between hosts.IMPORTANCEMethanogens are constant inhabitants in the human gut microbiota in which Methanosphaera stadtmanae was the only cultivated Methanosphaera representative. We grew Candidatus Methanosphaera massiliense sp. nov. from one human feces sample in a novel culture medium under a nitrogen atmosphere. Systematic research for methanogens in human and animal fecal samples detected Ca. M. massiliense in pig and red kangaroo feces, raising the possibility of its zoonotic acquisition. Host specificity, source of acquisition, and adaptation of methanogens should be further investigated.
Collapse
Affiliation(s)
- Virginie Pilliol
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Ecole de Médecine Dentaire, Marseille, France
| | - Madjid Morsli
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | - Laureline Terlier
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
| | - Yasmine Hassani
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | - Ihab Malat
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | - Cheick Oumar Guindo
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | - Bernard Davoust
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | | | - Michel Drancourt
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| | - Gérard Aboudharam
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- Aix-Marseille Université, Ecole de Médecine Dentaire, Marseille, France
| | | | - Elodie Terrer
- Aix-Marseille Université, IRD, MEPHI, IHU Méditerranée Infection, Marseille, France
- IHU Méditerranée Infection, Marseille, France
| |
Collapse
|
3
|
Zhang T, Guo Y, Fan X, Liu M, Xu J, Zeng X, Sun Y, Wu Z, Pan D. Protection Mechanism of Metal Ion Pre-Stress on Lactobacillus acidophilus CICC 6074 under Acid Tolerance. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:13304-13315. [PMID: 37639527 DOI: 10.1021/acs.jafc.3c01970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
The prerequisite for the probiotic effect of lactic acid bacteria is that they could survive the acid stress environment of production and application. In this experiment, the mechanism for the effect of different metal ion pre-stress on the acid-tolerant survival of Lactobacillus was investigated. Scanning electron microscopy, Fourier infrared spectroscopy, and flow cytometry were used to analyze the condition of bacteria after acid treatment, which revealed that different metal ion pre-stress could improve the survival ability of Lactobacillus acidophilus CICC 6074 under low acid conditions by improving cell morphology, mitigating cell membrane damage, and regulating surface protein expression. Furthermore, Tandem Mass Tags (TMT) proteomic analysis revealed that Mn2+ pre-stress showed relatively more superior protective effects on acid tolerance in L. acidophilus CICC 6074 through activation of DNA replication, RNA synthesis, S-layer protein secretion, H+-ATPase enzyme activity, etc. This study will provide new ideas and a theoretical basis for the development and application of lactic acid bacteria.
Collapse
Affiliation(s)
- Tao Zhang
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Yuxing Guo
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing 210023, China
| | - Xiankang Fan
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Mingzhen Liu
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Jue Xu
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Xiaoqun Zeng
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Yangying Sun
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Zhen Wu
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| | - Daodong Pan
- Key Laboratory of Animal Protein Food Processing Technology of Zhejiang Province, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo 315211, China
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo 315211, China
| |
Collapse
|
4
|
Wu HY, Wei ZL, Shi DY, Li HB, Li XM, Yang D, Zhou SQ, Peng XX, Yang ZW, Yin J, Chen TJ, Li JW, Jin M. Simulated Gastric Acid Promotes the Horizontal Transfer of Multidrug Resistance Genes across Bacteria in the Gastrointestinal Tract at Elevated pH Levels. Microbiol Spectr 2023; 11:e0482022. [PMID: 37070984 PMCID: PMC10269839 DOI: 10.1128/spectrum.04820-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 03/31/2023] [Indexed: 04/19/2023] Open
Abstract
The assessment of factors that can promote the transmission of antibiotic resistance genes (ARGs) across bacteria in the gastrointestinal tract is in great demand to understand the occurrence of infections related to antibiotic-resistant bacteria (ARB) in humans. However, whether acid-resistant enteric bacteria can promote ARG transmission in gastric fluid under high-pH conditions remains unknown. This study assessed the effects of simulated gastric fluid (SGF) at different pH levels on the RP4 plasmid-mediated conjugative transfer of ARGs. Moreover, transcriptomic analysis, measurement of reactive oxygen species (ROS) levels, assessment of cell membrane permeability, and real-time quantitative assessment of the expression of key genes were performed to identify the underlying mechanisms. The frequency of conjugative transfer was the highest in SGF at pH 4.5. Antidepressant consumption and certain dietary factors further negatively impacted this situation, with 5.66-fold and 4.26-fold increases in the conjugative transfer frequency being noted upon the addition of sertraline and 10% glucose, respectively, compared with that in the control group without any additives. The induction of ROS generation, the activation of cellular antioxidant systems, increases in cell membrane permeability, and the promotion of adhesive pilus formation were factors potentially contributing to the increased transfer frequency. These findings indicate that conjugative transfer could be enhanced under certain circumstances in SGF at elevated pH levels, thereby facilitating ARG transmission in the gastrointestinal tract. IMPORTANCE The low pH of gastric acid kills unwanted microorganisms, in turn affecting their inhabitation in the intestine. Hence, studies on the factors that influence antibiotic resistance gene (ARG) propagation in the gastrointestinal tract and on the underlying mechanisms are limited. In this study, we constructed a conjugative transfer model in the presence of simulated gastric fluid (SGF) and found that SGF could promote the dissemination of ARGs under high-pH conditions. Furthermore, antidepressant consumption and certain dietary factors could negatively impact this situation. Transcriptomic analysis and a reactive oxygen species assay revealed the overproduction of reactive oxygen species as a potential mechanism by which SGF could promote conjugative transfer. This finding can help provide a comprehensive understanding of the bloom of antibiotic-resistant bacteria in the body and create awareness regarding the risk of ARG transmission due to certain diseases or an improper diet and the subsequent decrease in gastric acid levels.
Collapse
Affiliation(s)
- Hai-yan Wu
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Zi-lin Wei
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Dan-yang Shi
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Hai-bei Li
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Xin-mei Li
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Dong Yang
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Shu-qing Zhou
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Xue-xia Peng
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Zhong-wei Yang
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Jing Yin
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Tian-jiao Chen
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Jun-wen Li
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| | - Min Jin
- Department of Environment and Health, Tianjin Institute of Environmental and Operational Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China
| |
Collapse
|
5
|
Bondegaard PW, Torp AM, Guerra P, Kristensen KA, Christfort JF, Krogfelt KA, Nielsen LH, Zor K, Boisen A, Mortensen MS, Bahl MI, Licht TR. Delivery of E. coli Nissle to the mouse gut by mucoadhesive microcontainers does not improve its competitive ability against strains linked to ulcerative colitis. FEMS Microbiol Lett 2023; 370:fnad110. [PMID: 37863838 PMCID: PMC10612143 DOI: 10.1093/femsle/fnad110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 10/02/2023] [Accepted: 10/19/2023] [Indexed: 10/22/2023] Open
Abstract
For patients with ulcerative colitis (UC), administration of the probiotic E. coli Nissle (EcN) holds promise for alleviation of disease symptoms. The mechanisms are unclear, but it has been hypothesised that a capacity of the probiotic to outcompete potentially detrimental UC-associated E. coli strains plays an important role. However, this could previously not be confirmed in a mouse model of competition between EcN and two UC-associated strains, as reported by Petersen et al. 2011. In the present study, we re-evaluated the idea, hypothesising that delivery of EcN by a micro device dosing system (microcontainers), designed for delivery into the intestinal mucus, could support colonisation and confer a competition advantage compared to classical oral dosing. Six groups of mice were pre-colonised with one of two UC-associated E. coli strains followed by oral delivery of EcN, either in capsules containing microcontainers with freeze-dried EcN powder, capsules containing freeze-dried EcN powder, or as a fresh sucrose suspension. Co-colonisation between the probiotic and the disease-associated strains was observed regardless of dosing method, and no competition advantages linked to microcontainer delivery were identified within this setup. Other approaches are thus needed if the competitive capacity of EcN in the gut should be improved.
Collapse
Affiliation(s)
- Pi Westi Bondegaard
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Anders Meyer Torp
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Priscila Guerra
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Katja Ann Kristensen
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | | | - Karen Angeliki Krogfelt
- Department of Science and Environment, Molecular and Medical Biology, Roskilde University, Roskilde, 4000, Denmark
| | - Line Hagner Nielsen
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Kinga Zor
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Anja Boisen
- Department of Health Technology, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | | | - Martin Iain Bahl
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| | - Tine Rask Licht
- National Food Institute, Technical University of Denmark, Kgs. Lyngby, 2800, Denmark
| |
Collapse
|
6
|
Woodward SE, Vogt SL, Peña-Díaz J, Melnyk RA, Cirstea M, Serapio-Palacios A, Neufeld LMP, Huus KE, Wang MA, Haney CH, Finlay BB. Gastric acid and escape to systemic circulation represent major bottlenecks to host infection by Citrobacter rodentium. THE ISME JOURNAL 2023; 17:36-46. [PMID: 36153406 PMCID: PMC9751147 DOI: 10.1038/s41396-022-01321-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 09/05/2022] [Accepted: 09/08/2022] [Indexed: 11/09/2022]
Abstract
The gastrointestinal (GI) environment plays a critical role in shaping enteric infections. Host environmental factors create bottlenecks, restrictive events that reduce the genetic diversity of invading bacterial populations. However, the identity and impact of bottleneck events on bacterial infection are largely unknown. We used Citrobacter rodentium infection of mice, a model of human pathogenic Escherichia coli infections, to examine bacterial population dynamics and quantify bottlenecks to host colonization. Using Sequence Tag-based Analysis of Microbial Populations (STAMP) we characterized the founding population size (Nb') and relatedness of C. rodentium populations at relevant tissue sites during early- and peak-infection. We demonstrate that the GI environment severely restricts the colonizing population, with an average Nb' of only 12-43 lineages (of 2,000+ inoculated) identified regardless of time or biogeographic location. Passage through gastric acid and escape to the systemic circulation were identified as major bottlenecks during C. rodentium colonization. Manipulating such events by increasing gastric pH dramatically increased intestinal Nb'. Importantly, removal of the stomach acid barrier had downstream consequences on host systemic colonization, morbidity, and mortality. These findings highlight the capability of the host GI environment to limit early pathogen colonization, controlling the population of initial founders with consequences for downstream infection outcomes.
Collapse
Affiliation(s)
- Sarah E Woodward
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Stefanie L Vogt
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Jorge Peña-Díaz
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Ryan A Melnyk
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Mihai Cirstea
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | | | - Laurel M P Neufeld
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
| | - Kelsey E Huus
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Madeline A Wang
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - Cara H Haney
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada
| | - B Brett Finlay
- Department of Microbiology and Immunology, University of British Columbia, Vancouver, BC, Canada.
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, Canada.
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
| |
Collapse
|
7
|
Simulated Colonic Fluid Replicates the In Vivo Growth Capabilities of Citrobacter rodentium cpxRA Mutants and Uncovers Additive Effects of Cpx-Regulated Genes on Fitness. Infect Immun 2022; 90:e0031422. [PMID: 36000875 PMCID: PMC9476912 DOI: 10.1128/iai.00314-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Citrobacter rodentium is an attaching and effacing (A/E) pathogen used to model enteropathogenic and enterohemorrhagic Escherichia coli infections in mice. During colonization, C. rodentium must adapt to stresses in the gastrointestinal tract, such as antimicrobial peptides, pH changes, and bile salts. The Cpx envelope stress response (ESR) is a two-component system used by some bacteria to remediate stress by modulating gene expression, and it is necessary for C. rodentium pathogenesis in mice. Here, we utilized simulated colonic fluid (SCF) to mimic the gastrointestinal environment, which we show strongly induces the Cpx ESR and highlights a fitness defect specific to the ΔcpxRA mutant. While investigating genes in the Cpx regulon that may contribute to C. rodentium pathogenesis, we found that the absence of the Cpx ESR resulted in higher expression of the locus of enterocyte effacement (LEE) master regulator, ler, and that the genes yebE, ygiB, bssR, and htpX relied on CpxRA for proper expression. We then determined that CpxRA and select gene mutants were essential for proper growth in SCF when in the presence of extraneous stressors and in competition. Although none of the Cpx-regulated gene mutants exhibited marked virulence phenotypes in vivo, the ΔcpxRA mutant had reduced colonization and attenuated virulence, as previously determined, which replicated the in vitro growth phenotypes specific to SCF. Overall, these results indicate that the ΔcpxRA virulence defect is not due to any single Cpx regulon gene examined. Instead, attenuation may be the result of defective growth in the colonic environment resulting from the collective impact of multiple Cpx-regulated genes.
Collapse
|
8
|
Biosensors based on zinc oxide thin-film transistors using recyclable plastic substrates as an alternative for real-time pathogen detection. Talanta 2022; 237:122970. [PMID: 34736694 DOI: 10.1016/j.talanta.2021.122970] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 11/22/2022]
Abstract
The fabrication of biosensors has different future applications mainly from the perspective of eco-friendly technologies. Label-free strategies, recyclable materials and low-temperature processing are parameters to consider for the development of a new generation of biosensor devices. In this work, Zinc oxide (ZnO) Thin-film Transistors (TFTs) using recyclable plastic substrates were used for real-time enteropathogenic Escherichia coli detection as an approach for biosensing (bio-TFTs). Fourier Transform Infrared Spectroscopy was used to verify the characteristic absorption peaks at the different steps of the bio-TFT assembly process. The bio-TFTs are ready to observe the bacterial detection by electrical characterization. Finally, detection was validated by a coupled strategy that fuses the genomic DNA extraction from bacteria attached in situ over bio-TFTs surface and, the development of the Polymerase Chain Reaction to amplify specific genes from enteropathogenic Escherichia coli.
Collapse
|
9
|
Lee JB, Kim SK, Yoon JW. Pathophysiology of enteropathogenic Escherichia coli during a host infection. J Vet Sci 2022; 23:e28. [PMID: 35187883 PMCID: PMC8977535 DOI: 10.4142/jvs.21160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 12/04/2021] [Accepted: 12/07/2021] [Indexed: 11/20/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) is a major cause of infantile diarrhea in developing countries. However, sporadic outbreaks caused by this microorganism in developed countries are frequently reported recently. As an important zoonotic pathogen, EPEC is being monitored annually in several countries. Hallmark of EPEC infection is formation of attaching and effacing (A/E) lesions on the small intestine. To establish A/E lesions during a gastrointestinal tract (GIT) infeciton, EPEC must thrive in diverse GIT environments. A variety of stress responses by EPEC have been reported. These responses play significant roles in helping E. coli pass through GIT environments and establishing E. coli infection. Stringent response is one of those responses. It is mediated by guanosine tetraphosphate. Interestingly, previous studies have demonstrated that stringent response is a universal virulence regulatory mechanism present in many bacterial pathogens including EPEC. However, biological signficance of a bacterial stringent response in both EPEC and its interaction with the host during a GIT infection is unclear. It needs to be elucidated to broaden our insight to EPEC pathogenesis. In this review, diverse responses, including stringent response, of EPEC during a GIT infection are discussed to provide a new insight into EPEC pathophysiology in the GIT.
Collapse
Affiliation(s)
- Jun Bong Lee
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Se Kye Kim
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| | - Jang Won Yoon
- College of Veterinary Medicine & Institute of Veterinary Science, Kangwon National University, Chuncheon 24341, Korea
| |
Collapse
|
10
|
Alfinete N, Bolukaoto JY, Heine L, Potgieter N, Barnard TG. Virulence and phylogenetic analysis of enteric pathogenic Escherichia coli isolated from children with diarrhoea in South Africa. Int J Infect Dis 2021; 114:226-232. [PMID: 34775113 DOI: 10.1016/j.ijid.2021.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 10/22/2021] [Accepted: 11/06/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Diarrhoeagenic E. coli pose a significant risk to human health. As such, determining the source(s) of these bacteria when isolated from patients with diarrhoea is an important step in disease prevention. OBJECTIVES This study aimed to identify the presence of genes coding for virulence and phylogroups among E. coli isolated from children hospitalised due to diarrhoea in Limpopo, South Africa. METHODS E. coli isolates were identified by VITEK®-2 automated system. An 11-gene multiplex PCR was used to differentiate five pathogenic types of E. coli: enteroaggregative (EAEC), enteroinvasive (EIEC), enterohaemorrhagic (EHEC), enteropathogenic (EPEC) and enterotoxigenic (ETEC). Clermont quadruplex PCR method was used to identify phylogroups of isolates. RESULTS From the 133 isolates tested, 79 were confirmed as E. coli of which (19.0%, 15/79) were commensals and 81.0% (64/79) isolates were positive for at least one pathotype of which ETEC was predominant (16.5%, 13/79), followed by EAEC (10.1%, 8/79), EPEC (7.6%, 6/79) and EHEC (2.5%, 2/79). Hybrid pathotypes were also detected and EAEC/ETEC was predominant (25.3%, 20/79). Phylogroup B2 was predominant (30.4%, 24/79), followed by group B1 (22.8%, 18/79), phylogroup C and E both had (12.7%, 10/79) each. Just over six percent (5/79) of isolates were non-typable. CONCLUSION There was a high distribution of diarrhoeagenic E. coli associated with different phylogroups among children living in Limpopo province, South Africa. This emphasises the importance of future monitoring of virulence and phylogroup distribution of E. coli isolates in this province in particular and South Africa as a whole.
Collapse
Affiliation(s)
- Ntando Alfinete
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - John Y Bolukaoto
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - Lee Heine
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - Natasha Potgieter
- School of Mathematical and Natural Sciences, University of Venda, Limpopo Province, South Africa
| | - Tobias G Barnard
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa.
| |
Collapse
|
11
|
Bolukaoto JY, Singh A, Alfinete N, Barnard TG. Occurrence of Hybrid Diarrhoeagenic Escherichia coli Associated with Multidrug Resistance in Environmental Water, Johannesburg, South Africa. Microorganisms 2021; 9:2163. [PMID: 34683484 PMCID: PMC8538365 DOI: 10.3390/microorganisms9102163] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/25/2021] [Accepted: 09/27/2021] [Indexed: 12/20/2022] Open
Abstract
This study was undertaken to determine the virulence and antibiotic resistance profiles of diarrhoeagenic Escherichia coli (DEC) in environmental waters of Johannesburg, South Africa. Samples were collected and cultured on selective media. An 11-plex PCR assay was used to differentiate five DEC, namely: enteroaggregative (EAEC), enterohaemorrhagic (EHEC), enteroinvasive (EIEC), enteropathogenic (EPEC) and enterotoxigenic (ETEC). The antibiotic resistance profile of isolates was determined using the VITEK®-2 automated system. The virulence profiles of 170 E. coli tested showed that 40% (68/170) were commensals and 60% (102/170) were pathogenic. EPEC had a prevalence of 19.2% (32/170), followed by ETEC 11.4% (19/170), EAEC 6% (10/170) and EHEC 3% (5/170). Hybrid DEC carrying a combination of simultaneously two and three pathogenic types was detected in twenty-eight and nine isolates, respectively. The antibiotic susceptibility testing showed isolates with multidrug resistance, including cefuroxime (100%), ceftazidime (86%), cefotaxime (81%) and cefepime (79%). This study highlighted the widespread occurrence of DEC and antibiotic resistance strains in the aquatic ecosystem of Johannesburg. The presence of hybrid pathotypes detected in this study is alarming and might lead to more severe diseases. There is a necessity to enhance surveillance in reducing the propagation of pathogenic and antibiotic-resistant strains in this area.
Collapse
Affiliation(s)
| | | | | | - Tobias G. Barnard
- Water and Health Research Centre, University of Johannesburg, Doornfontein 2092, South Africa; (J.Y.B.); (A.S.); (N.A.)
| |
Collapse
|
12
|
A Possible Flow Cytometry-Based Viability and Vitality Assessment Protocol for Pathogenic Vibrio cholerae O1 and O139 Postexposure to Simulated Gastric Fluid. BIOMED RESEARCH INTERNATIONAL 2021; 2021:5551845. [PMID: 34212032 PMCID: PMC8208853 DOI: 10.1155/2021/5551845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 05/21/2021] [Accepted: 05/27/2021] [Indexed: 12/26/2022]
Abstract
During the intake of contaminated water, for diarrheal disease to occur, Vibrio cholerae must survive through the bactericidal digestive secretion of gastric fluid during passage through the stomach. Determining the viability of these bacteria is challenging, with the standard cultivation methods for viability being time-consuming and unable to culture cells that may still function accordingly. This study assessed the use of enzyme action and membrane integrity as alternatives for determining vitality and viability, respectively, in gastric acid-stressed pathogenic Vibrio cholerae O1 and O139, using fluorescent probes thiazole orange (TO) for viability based on membrane integrity, carboxyfluorescein diacetate (CFDA) with acetoxymethyl ester (AM) for vitality based on metabolic activity, and propidium iodide (PI) for cell death/damage due to loss of membrane integrity, with flow cytometry. Simulated gastric fluid-treated bacterial cells were labelled with blends of TO+PI and CFDA-AM+PI, and these stained cells were separated into heterologous populations based on their fluorescence signal. The gastric acid exposed cells presented with high green fluorescence signals after staining with the metabolic probe CFDA-AM, which indicated intact (live) cells due to being metabolically active, whereas when the same cells were stained with the DNA probe (TO), these appeared to be in a “stressed state” due to loss of membrane integrity. Damaged cells (dead cells) showed high red fluorescence levels after staining with PI probe. The use of flow cytometry with fluorescent probes is a favorable method for evaluating the vitality and viability of bacteria when cells are labelled with a combination of CFDA-AM+PI.
Collapse
|
13
|
Sheikh SW, Ali A, Ahsan A, Shakoor S, Shang F, Xue T. Insights into Emergence of Antibiotic Resistance in Acid-Adapted Enterohaemorrhagic Escherichia coli. Antibiotics (Basel) 2021; 10:antibiotics10050522. [PMID: 34063307 PMCID: PMC8147483 DOI: 10.3390/antibiotics10050522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/15/2021] [Accepted: 04/29/2021] [Indexed: 12/17/2022] Open
Abstract
The emergence of multidrug-resistant pathogens presents a global challenge for treating and preventing disease spread through zoonotic transmission. The water and foodborne Enterohaemorrhagic Escherichia coli (EHEC) are capable of causing intestinal and systemic diseases. The root cause of the emergence of these strains is their metabolic adaptation to environmental stressors, especially acidic pH. Acid treatment is desired to kill pathogens, but the protective mechanisms employed by EHECs cross-protect against antimicrobial peptides and thus facilitate opportunities for survival and pathogenesis. In this review, we have discussed the correlation between acid tolerance and antibiotic resistance, highlighting the identification of novel targets for potential production of antimicrobial therapeutics. We have also summarized the molecular mechanisms used by acid-adapted EHECs, such as the two-component response systems mediating structural modifications, competitive inhibition, and efflux activation that facilitate cross-protection against antimicrobial compounds. Moving beyond the descriptive studies, this review highlights low pH stress as an emerging player in the development of cross-protection against antimicrobial agents. We have also described potential gene targets for innovative therapeutic approaches to overcome the risk of multidrug-resistant diseases in healthcare and industry.
Collapse
Affiliation(s)
- Salma Waheed Sheikh
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
| | - Ahmad Ali
- School of Agronomy, Anhui Agricultural University, Hefei 230036, China;
| | - Asma Ahsan
- Faculty of Life Sciences, University of Central Punjab, Lahore 54000, Punjab, Pakistan;
| | - Sidra Shakoor
- Station de Neucfchateau, CIRAD, 97130 Sainte-Marie, Capesterre Belle Eau, Guadeloupe, France;
| | - Fei Shang
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
| | - Ting Xue
- School of Life Sciences, Anhui Agricultural University, Hefei 230036, China;
- Correspondence: (F.S.); (T.X.); Tel.: +86-551-657-87380 (F.S.); +86-551-657-80690 (T.X.)
| |
Collapse
|
14
|
Chen X, Liu Y, Pan D, Cao M, Wang X, Wang L, Xu Y, Wang Y, Yan J, Liu J, Yang M. 68Ga-NOTA PET imaging for gastric emptying assessment in mice. BMC Gastroenterol 2021; 21:69. [PMID: 33581729 PMCID: PMC7881688 DOI: 10.1186/s12876-021-01642-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 02/03/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Positron emission tomography (PET) has the potential for visualization and quantification of gastric emptying (GE). The traditional Chinese medicine (TCM) has been recognized promising for constipation. This study aimed to establish a PET imaging method for noninvasive GE measurement and to evaluate the efficacy of a TCM on delayed GE caused by constipation using PET imaging. METHODS [68Ga]Ga-NOTA was synthesized as the tracer and sesame paste with different viscosity were selected as test meals. The dynamic PET scans were performed after [68Ga]Ga-NOTA mixed with test meals were administered to normal mice. Two methods were utilized for the quantification of PET imaging. A constipation mouse model was treated with maren chengqi decoction (MCD), and the established PET imaging scans were performed after the treatment. RESULTS [68Ga]Ga-NOTA was synthesized within 20 min, and its radiochemical purity was > 95%. PET images showed the dynamic process of GE. %ID/g, volume, and total activity correlated well with each other. Among which, the half of GE time derived from %ID/g for 4 test meals were 3.92 ± 0.87 min, 13.1 ± 1.25 min, 17.8 ± 1.31 min, and 59.7 ± 3.11 min, respectively. Constipation mice treated with MCD showed improved body weight and fecal conditions as well as ameliorated GE measured by [68Ga]Ga-NOTA PET. CONCLUSIONS A PET imaging method for noninvasive GE measurement was established with stable radiotracer, high image quality, and reliable quantification methods. The efficacy of MCD on delayed GE was demonstrated using PET.
Collapse
Affiliation(s)
- Xueyan Chen
- Department of Veterinary Medicine, Southwest University, Rongchang, Chongqing, 402460, China
| | - Yu Liu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Donghui Pan
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Maoyu Cao
- Department of Veterinary Medicine, Southwest University, Rongchang, Chongqing, 402460, China
| | - Xinyu Wang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Lizhen Wang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Yuping Xu
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Yan Wang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Junjie Yan
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China
| | - Juan Liu
- Department of Veterinary Medicine, Southwest University, Rongchang, Chongqing, 402460, China. .,Immunology Center, Medical Research Institute of Southwest University, Rongchang, Chongqing, 402460, China.
| | - Min Yang
- NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, 214063, Jiangsu, China.
| |
Collapse
|
15
|
Salinas Domínguez R, Domínguez Jiménez MÁ, Orduña Díaz A. Antibody Immobilization in Zinc Oxide Thin Films as an Easy-Handle Strategy for Escherichia coli Detection. ACS OMEGA 2020; 5:20473-20480. [PMID: 32832800 PMCID: PMC7439397 DOI: 10.1021/acsomega.0c02583] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/14/2020] [Indexed: 06/01/2023]
Abstract
The antibody immobilization compatible with low-cost materials and label-free strategies is a challenge for biosensor device fabrication. In this study, ZnO thin film deposition was carried out on corning glass substrates by ultrasonic spray pyrolysis at 200 °C. The thin films were analyzed as platforms for enteropathogenic Escherichia coli (E. coli EPEC) antibody immobilization. The modification of thin films from the functionalization and antibody immobilization steps was visualized using Fourier transform infrared spectroscopy (FTIR) spectroscopy, and surface changes were observed by atomic force microscopy. The obtained FTIR spectra after functionalization showed a contribution of the amino group (NH2) derived from silane (3-aminopropyltrimethoxysilane). The antibody immobilization showed an amide I conserved signal corresponding to the C=O stretching vibrations and the amide II signal related to the N-H scissor vibration mode. In this way, the signals observed are correlated with the presence of antibody immobilized on the film. The ZnO film morphology changes after every stage of the process and allows observing the antibody distribution on the immobilized surface. In order to validate the antibody recognition capability as well as the E. coli EPEC detection in situ, polymerase chain reaction was used.
Collapse
Affiliation(s)
| | - Miguel Ángel Domínguez Jiménez
- Centro
de Investigaciones en Dispositivos Semiconductores, Instituto de Ciencias, Benemérita Universidad Autónoma de Puebla
(BUAP), Puebla 72570, Mexico
| | - Abdú Orduña Díaz
- Centro
de Investigación en Biotecnología Aplicada del Instituto Politécnico
Nacional (CIBA-IPN), Tlaxcala 72197, Mexico
| |
Collapse
|
16
|
Nové M, Kincses A, Molnár J, Amaral L, Spengler G. The Role of Efflux Pumps and Environmental pH in Bacterial Multidrug Resistance. In Vivo 2020; 34:65-71. [PMID: 31882464 DOI: 10.21873/invivo.11746] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 10/03/2019] [Accepted: 10/11/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND/AIM One of the most studied bacterial resistance mechanisms is the resistance related to multidrug efflux pumps. In our study the pump activity of the Escherichia coli K-12 AG100 strain expressing the AcrAB-TolC pump system was investigated at pH 7 and pH 5 in the presence of the efflux pump inhibitor (EPI) promethazine (PMZ). MATERIALS AND METHODS The EPI activity was assessed by real-time fluorimetry. The influence of PMZ treatment on the relative expression of the pump genes acrA, acrB and their regulators marA, marB, marR, the stress genes soxS, rob, as well as the bacterial growth control genes ftsI, and sdiA were determined by RT-qPCR. RESULTS The EPI activity of PMZ was more effective at neutral pH. The PMZ treatment induced a significant stress response in the bacterium at acidic pH by the up-regulation of genes. CONCLUSION The genetic system that regulates the activity of the main efflux pump is pH-dependent.
Collapse
Affiliation(s)
- Márta Nové
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Annamária Kincses
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - József Molnár
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Leonard Amaral
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary.,Travel Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Gabriella Spengler
- Department of Medical Microbiology and Immunobiology, Faculty of Medicine, University of Szeged, Szeged, Hungary
| |
Collapse
|
17
|
Salive AFV, Prudêncio CV, Baglinière F, Oliveira LL, Ferreira SO, Vanetti MCD. Comparison of stress conditions to induce viable but non-cultivable state in Salmonella. Braz J Microbiol 2020; 51:1269-1277. [PMID: 32291740 DOI: 10.1007/s42770-020-00261-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 03/10/2020] [Indexed: 12/18/2022] Open
Abstract
Salmonella can enter on the viable but non-culturable state (VBNC), characterized by the loss of ability to grow in routine culture media hindering detection by conventional methods and underestimation of the pathogen. Despite advances in research done so far, studies comparing conditions that lead Salmonella into the VBNC state are scarce. The main objective of this study was to evaluate different stresses to induce Salmonella to the VNBC state. Osmotic (1.2 M NaCl), acid (peracetic acid, 5.66 mg/mL) and oxidative (hydrogen peroxide, 1.20 mg/mL) stress were used at 4 °C to induce Salmonella enterica serovars Enteritidis and Typhimurium to the VBNC state. The culturability loss was monitored in the brain heart infusion (BHI) broth and agar, and the viability was determined by fluorescence microscopy, using the Live/Dead® kit, and by flow cytometry. Besides, the morphological characterization by atomic force microscopy (AFM) was performed. Storage in 1.2 M NaCl at 4 °C induced the VBNC state in Salmonella cells for periods longer than 121 days, and the percentage of viable cells has reached above 80.9%. More aggressive stress conditions promoted by peracetic acid and hydrogen peroxide induced the VBNC state in periods of, at most 0.14 day, and resulted in percentages of 8.5% to 45.5% viable cells, respectively. The counts of viable cells in the flow cytometer corroborate the results obtained by microscopic counts. The VBNC cells obtained in 1.2 M NaCl at 4 °C showed morphological changes, reducing the size and changing the morphology from bacillary to coccoid. No morphological change was observed on the cells stressed by acid or oxidant compounds.
Collapse
Affiliation(s)
| | - Cláudia Vieira Prudêncio
- Center of Biological and Health Sciences, Federal University of Western of Bahia, Barreiras, Bahia, Brazil
| | - François Baglinière
- Department of Microbiology, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil
| | | | | | | |
Collapse
|
18
|
Pienaar JA, Singh A, Barnard TG. Membrane modification as a survival mechanism through gastric fluid in non-acid adapted enteropathogenic Escherichia coli (EPEC). Microb Pathog 2020; 144:104180. [PMID: 32240767 DOI: 10.1016/j.micpath.2020.104180] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/26/2020] [Accepted: 03/27/2020] [Indexed: 01/04/2023]
Abstract
In bacterial cells, the cytoplasmic membrane forms a barrier between the environment and the cell's cytoplasm. This barrier regulates which substances (and the amount) that leave and enter the cell, to maintain homeostasis between the cytoplasm and the external environment. One of the mechanisms employed to maintain structure and functionality during exposure to environmental stress is adaptation of the membrane lipids. The aim of this study was to investigate membrane alteration as a possible survival method of non-acid adapted enteropathogenic Escherichia coli (E. coli) (EPEC) (as could be found in contaminated water or unprocessed food) through simulated gastric fluid (SGF). Enteropathogenic E. coli was grown in nutrient-rich media and then exposed to SGF of various pH (1.5, 2.5, 3.5, or 4.5) for 180 min. Flow cytometry was utilised to examine membrane integrity; and morphological changes were investigated using transmission electron microscopy (TEM). Gas chromatography-mass spectrometry (GC-MS) was used to assess the membrane lipid composition. The results of this study showed that SGF treatment caused membrane damage, as well as cell wall thickening and irregular plasma membranes. The morphological changes were accompanied by membrane lipid changes indicative of decreased membrane fluidity and increased rigidity. The findings suggest that non-acid adapted EPEC can perceive pH change in the environment and adapt accordingly.
Collapse
Affiliation(s)
- Jennifer Anne Pienaar
- Department of Biomedical Technology, University of Johannesburg, Doornfontein, South Africa; Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa
| | - Atheesha Singh
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa.
| | - Tobias George Barnard
- Water and Health Research Centre, University of Johannesburg, Doornfontein, South Africa
| |
Collapse
|
19
|
An acid-tolerance response system protecting exponentially growing Escherichia coli. Nat Commun 2020; 11:1496. [PMID: 32198415 PMCID: PMC7083825 DOI: 10.1038/s41467-020-15350-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/05/2020] [Indexed: 01/05/2023] Open
Abstract
The ability to grow at moderate acidic conditions (pH 4.0–5.0) is important to Escherichia coli colonization of the host’s intestine. Several regulatory systems are known to control acid resistance in E. coli, enabling the bacteria to survive under acidic conditions without growth. Here, we characterize an acid-tolerance response (ATR) system and its regulatory circuit, required for E. coli exponential growth at pH 4.2. A two-component system CpxRA directly senses acidification through protonation of CpxA periplasmic histidine residues, and upregulates the fabA and fabB genes, leading to increased production of unsaturated fatty acids. Changes in lipid composition decrease membrane fluidity, F0F1-ATPase activity, and improve intracellular pH homeostasis. The ATR system is important for E. coli survival in the mouse intestine and for production of higher level of 3-hydroxypropionate during fermentation. Furthermore, this ATR system appears to be conserved in other Gram-negative bacteria. The ability to grow at acidic pH is crucial for E. coli colonization of the host’s intestine. Here, the authors identify an acid-tolerance response system that is important for E. coli exponential growth at pH 4.2, survival in the mouse intestine, and production of 3-hydroxypropionate during fermentation.
Collapse
|
20
|
Woodward SE, Krekhno Z, Finlay BB. Here, there, and everywhere: How pathogenicEscherichia colisense and respond to gastrointestinal biogeography. Cell Microbiol 2019; 21:e13107. [DOI: 10.1111/cmi.13107] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/22/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022]
Affiliation(s)
- Sarah E. Woodward
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
| | - Zakhar Krekhno
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
| | - B. Brett Finlay
- Department of Microbiology and ImmunologyUniversity of British Columbia Vancouver British Columbia Canada
- Michael Smith LaboratoriesUniversity of British Columbia Vancouver British Columbia Canada
- Department of Biochemistry and Molecular BiologyUniversity of British Columbia Vancouver British Columbia Canada
| |
Collapse
|