1
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Santos LS, Rossi DA, Braz RF, Fonseca BB, Guidotti–Takeuchi M, Alves RN, Beletti ME, Almeida-Souza HO, Maia LP, Santos PDS, de Souza JB, de Melo RT. Roles of viable but non-culturable state in the survival of Campylobacter jejuni. Front Cell Infect Microbiol 2023; 13:1122450. [PMID: 37056707 PMCID: PMC10086134 DOI: 10.3389/fcimb.2023.1122450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 03/09/2023] [Indexed: 03/30/2023] Open
Abstract
Despite being considered fragile and fastidious, Campylobacter jejuni is the most prevalent cause of foodborne bacterial gastroenteritis, and chicken meat is considered the main vehicle of transmission to humans. This agent can survive adverse conditions in the form of biofilms, but extreme stress (nutritional, oxidative and thermal) promotes the acquisition of a state called viable but not culturable (VBNC). The emergence of this pathogen worldwide and the recent international requirements in its control instigated us to qualitatively and quantitatively estimate the time required for the acquisition of the VBNC form in 27 strains of C. jejuni, characterize morphological aspects, determine its adaptive and invasive potential and perform comparative metabolomic evaluation. Extreme stress promoted the complete acquisition of the VBNC form in a mean time of 26 days. Starting from an average initial count of 7.8 log CFU/mL, the first four days determined the greatest average reduction of the culturable form of 3.2 log CFU/mL. The scanning and transmission image analyses showed a transition from the typical viable form (VT) to the VBNC form, with initial acquisition of the straight rod shape, followed by loss of the flagella and subdivision into two to 11 imperfect cocci arranged in a chain and rich in cellular content, until their individual release. RT-PCR identified the presence of ciaB and p19 transcripts in the 27 cultivable C. jejuni strains, a character maintained in the VBNC form only for p19 and in 59.3% (16/27) of the VBNC strains for the ciaB gene. The average inoculation of 1.8 log CFU/mL of C. jejuni VBNC into primary chicken embryo hepatocyte cells promoted the occurrence of apoptosis processes significantly after 24 hours of contact by one of the strains tested. In C. jejuni VBNC, we detected higher expression of metabolites linked to protective and adaptation mechanisms and of volatile organic precursor compounds indicative of metabolism interruption. The oscillations in the time of acquisition of the VBNC form together with the presence of transcripts for ciaB and p19, the identification of cell lysis and metabolites that ensure the maintenance of the pathogen alert to the fact that C. jejuni VBNC remains virulent and adapted to stress, which makes evident the potential danger of this latent form, which is not detectable by official methodologies.
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Affiliation(s)
- Leticia Silva Santos
- Laboratory of Molecular Epidemiology, Federal University of Uberlandia, Uberlandia, Brazil
| | - Daise Aparecida Rossi
- Laboratory of Molecular Epidemiology, Federal University of Uberlandia, Uberlandia, Brazil
| | | | | | | | | | | | | | - Larissa Prado Maia
- Biotechnology Institute, Federal University of Uberlandia, Uberlandia, Brazil
| | | | | | - Roberta Torres de Melo
- Laboratory of Molecular Epidemiology, Federal University of Uberlandia, Uberlandia, Brazil
- *Correspondence: Roberta Torres de Melo,
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2
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İzgördü ÖK, Darcan C, Kariptaş E. Overview of VBNC, a survival strategy for microorganisms. 3 Biotech 2022; 12:307. [PMID: 36276476 PMCID: PMC9526772 DOI: 10.1007/s13205-022-03371-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/20/2022] [Indexed: 11/01/2022] Open
Abstract
Microorganisms are exposed to a wide variety of stress factors in their natural environments. Under that stressful conditions, they move into a viable but nonculturable (VBNC) state to survive and maintain the vitality. At VBNC state, microorganisms cannot be detected by traditional laboratory methods, but they can be revived under appropriate conditions. Therefore, VBNC organisms cause serious food safety and public health problems. To date, it has been determined that more than 100 microorganism species have entered the VBNC state through many chemical and physical factors. During the last four decades, dating from the initial detection of the VBNC condition, new approaches have been developed for the induction, detection, molecular mechanisms, and resuscitation of VBNC cells. This review evaluates the current data of recent years on the inducing conditions and detection methods of the VBNC state, including with microorganisms on the VBNC state, their virulence, pathogenicity, and molecular mechanisms.
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Affiliation(s)
- Özge Kaygusuz İzgördü
- Biotechnology Application and Research Center, Bilecik Şeyh Edebali University, Bilecik, Turkey
| | - Cihan Darcan
- Department of Molecular Biology and Genetics, Bilecik Şeyh Edebali University, Bilecik, Turkey
| | - Ergin Kariptaş
- Department of Microbiology, Faculty of Medicine, Samsun University, Samsun, Turkey
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3
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Pokhrel D, Thames HT, Zhang L, Dinh TTN, Schilling W, White SB, Ramachandran R, Theradiyil Sukumaran A. Roles of Aerotolerance, Biofilm Formation, and Viable but Non-Culturable State in the Survival of Campylobacter jejuni in Poultry Processing Environments. Microorganisms 2022; 10:2165. [PMID: 36363757 PMCID: PMC9699079 DOI: 10.3390/microorganisms10112165] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/21/2022] [Accepted: 10/23/2022] [Indexed: 08/11/2023] Open
Abstract
Campylobacter jejuni is one of the most common causes of foodborne human gastroenteritis in the developed world. This bacterium colonizes in the ceca of chickens, spreads throughout the poultry production chain, and contaminates poultry products. Despite numerous on farm intervention strategies and developments in post-harvest antimicrobial treatments, C. jejuni is frequently detected on broiler meat products. This indicates that C. jejuni is evolving over time to overcome the stresses/interventions that are present throughout poultry production and processing. The development of aerotolerance has been reported to be a major survival strategy used by C. jejuni in high oxygen environments. Recent studies have indicated that C. jejuni can enter a viable but non-culturable (VBNC) state or develop biofilm in response to environmental stressors such as refrigeration and freezing stress and aerobic stress. This review provides an overview of different stressors that C. jejuni are exposed to throughout the poultry production chain and the genotypic and phenotypic survival mechanisms, with special attention to aerotolerance, biofilm formation, and development of the VBNC state.
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Affiliation(s)
- Diksha Pokhrel
- Department of Poultry Science, Mississippi State University, Mississippi, MS 39762, USA
| | - Hudson T. Thames
- Department of Poultry Science, Mississippi State University, Mississippi, MS 39762, USA
| | - Li Zhang
- Department of Poultry Science, Mississippi State University, Mississippi, MS 39762, USA
| | - Thu T. N. Dinh
- Tyson Foods, 2200 W. Don Tyson Parkway, Springdale, AR 72762, USA
| | - Wes Schilling
- Department of Poultry Science, Mississippi State University, Mississippi, MS 39762, USA
| | - Shecoya B. White
- Department of Food Science, Nutrition, and Health Promotion, Mississippi State University, Starkville, MS 39762, USA
| | - Reshma Ramachandran
- Department of Poultry Science, Mississippi State University, Mississippi, MS 39762, USA
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4
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Liu B, Lai J, Wu S, Jiang J, Kuang W. Endophytic bacterial community diversity in two citrus cultivars with different citrus canker disease resistance. Arch Microbiol 2021; 203:5453-5462. [PMID: 34406444 DOI: 10.1007/s00203-021-02530-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/26/2021] [Accepted: 08/13/2021] [Indexed: 12/29/2022]
Abstract
The selective infection of Xanthomonas citri pv. citri (Xcc) to citrus cultivars is universally known, but the relationship between endophytic bacteria and the resistance of host variety to canker disease remains unclear. In this study, endophytic bacterial populations of two citrus cultivars-the resistant satsuma mandarin and the susceptible Newhall navel orange-were analyzed through high-throughput sequencing. The results showed that endophytic bacterial community of satsuma mandarin was more abundant than that of Newhall navel orange. In addition, bacterial abundance was the highest in the spring samples, followed by that in summer and winter samples, in both the varieties. In all samples, the predominant phyla were Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes; the major genera were Bacillus and Stenotrophomonas, and the main species was Bacillus subtilis. According to the analysis of the predominant bacteria in the two citrus cultivars, B. subtilis with potential antagonistic characteristics against Xcc existed universally in all samples. However, the susceptible Newhall navel oranges were abundant in Bacillus subtilis and had a relatively large number of canker-causing cooperative bacteria such as Stenotrophomonas. The results suggested that endophytic bacterial community of the two citrus cultivars had some differences based on the season or plant tissue, and these differences were mainly in the quantity of bacteria, affecting citrus canker disease occurrence. In conclusion, the differences in endophytic bacteria on citrus cultivars might be related to host resistance or susceptibility to citrus canker disease.
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Affiliation(s)
- Bing Liu
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China.
| | - Jiahao Lai
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China
| | - Simeng Wu
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China
| | - Junxi Jiang
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China
| | - Weigang Kuang
- College of Agronomy, Jiangxi Agricultural University, Nanchang, 330045, Jiangxi, China.
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5
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Rosigkeit H, Kneißle L, Obruča S, Jendrossek D. The Multiple Roles of Polyphosphate in Ralstonia eutropha and Other Bacteria. Microb Physiol 2021; 31:163-177. [PMID: 34015783 DOI: 10.1159/000515741] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 03/06/2021] [Indexed: 11/19/2022]
Abstract
An astonishing variety of functions has been attributed to polyphosphate (polyP) in prokaryotes. Besides being a reservoir of phosphorus, functions in exopolysaccharide formation, motility, virulence and in surviving various forms of stresses such as exposure to heat, extreme pH, oxidative agents, high osmolarity, heavy metals and others have been ascribed to polyP. In this contribution, we will provide a historical overview on polyP, will then describe the key proteins of polyP synthesis, the polyP kinases, before we will critically assess of the underlying data on the multiple functions of polyP and provide evidence that - with the exception of a P-storage-function - most other functions of polyP are not relevant for survival of Ralstonia eutropha, a biotechnologically important beta-proteobacterial species.
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Affiliation(s)
- Hanna Rosigkeit
- Institute of Microbiology, University of Stuttgart, Stuttgart, Germany
| | - Lea Kneißle
- Institute of Microbiology, University of Stuttgart, Stuttgart, Germany
| | - Stanislav Obruča
- Faculty of Chemistry, Brno University of Technology, Brno, Czechia
| | - Dieter Jendrossek
- Institute of Microbiology, University of Stuttgart, Stuttgart, Germany
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6
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Shropshire H, Jones RA, Aguilo-Ferretjans MM, Scanlan DJ, Chen Y. Proteomics insights into the Burkholderia cenocepacia phosphorus stress response. Environ Microbiol 2021; 23:5069-5086. [PMID: 33684254 DOI: 10.1111/1462-2920.15451] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 03/02/2021] [Indexed: 11/26/2022]
Abstract
The Burkholderia cepacia complex is a group of Burkholderia species that are opportunistic pathogens causing high mortality rates in patients with cystic fibrosis. An environmental stress often encountered by these soil-dwelling and pathogenic bacteria is phosphorus limitation, an essential element for cellular processes. Here, we describe cellular and extracellular proteins differentially regulated between phosphate-deplete (0 mM, no added phosphate) and phosphate-replete (1 mM) growth conditions using a comparative proteomics (LC-MS/MS) approach. We observed a total of 128 and 65 unique proteins were downregulated and upregulated respectively, in the B. cenocepacia proteome. Of those downregulated proteins, many have functions in amino acid transport/metabolism. We have identified 24 upregulated proteins that are directly/indirectly involved in inorganic phosphate or organic phosphorus acquisition. Also, proteins involved in virulence and antimicrobial resistance were differentially regulated, suggesting B. cenocepacia experiences a dramatic shift in metabolism under these stress conditions. Overall, this study provides a baseline for further research into the biology of Burkholderia in response to phosphorus stress.
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Affiliation(s)
- Holly Shropshire
- BBSRC Midlands Integrative Biosciences Training Partnership, University of Warwick, Coventry, CV4 7AL, UK.,School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Rebekah A Jones
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | | | - David J Scanlan
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
| | - Yin Chen
- School of Life Sciences, University of Warwick, Coventry, CV4 7AL, UK
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7
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Molecular Mechanisms of Campylobacter Biofilm Formation and Quorum Sensing. Curr Top Microbiol Immunol 2021. [PMID: 33620656 DOI: 10.1007/978-3-030-65481-8_11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023]
Abstract
Even though Campylobacter spp. are known to be fastidious organisms, they can survive within the natural environment. One mechanism to withstand unfavourable conditions is the formation of biofilms, a multicellular structure composed of different bacterial and other microbial species which are embedded in an extracellular matrix. High oxygen levels, low substrate concentrations and the presence of external DNA stimulate the biofilm formation by C. jejuni. These external factors trigger internal adaptation processes, e.g. via regulating the expression of genes encoding proteins required for surface structure formation, as well as motility, stress response and antimicrobial resistance. Known genes impacting biofilm formation will be summarized in this review. The formation of biofilms as well as the expression of virulence genes is often regulated in a cell density depending manner by quorum sensing, which is mediated via small signalling molecules termed autoinducers. Even though quorum sensing mechanisms of other bacteria are well understood, knowledge on the role of these mechanisms in C. jejuni biofilm formation is still scarce. The LuxS enzyme involved in generation of autoinducer-2 is present in C. jejuni, but autoinducer receptors have not been identified so far. Phenotypes of C. jejuni strains lacking a functional luxS like reduced growth, motility, oxygen stress tolerance, biofilm formation, adhesion, invasion and colonization are also summarized within this chapter. However, these phenotypes are highly variable in distinct C. jejuni strains and depend on the culture conditions applied.
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8
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Gao R, Liao X, Zhao X, Liu D, Ding T. The diagnostic tools for viable but nonculturable pathogens in the food industry: Current status and future prospects. Compr Rev Food Sci Food Saf 2021; 20:2146-2175. [PMID: 33484068 DOI: 10.1111/1541-4337.12695] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/21/2020] [Accepted: 12/28/2020] [Indexed: 12/21/2022]
Abstract
Viable but nonculturable (VBNC) microorganisms have been recognized as pathogenic contaminants in foods and environments. The failure of VBNC cells to form the visible colonies hinders the ability to use conventional media for their detection. Efficient and rapid detection of pathogens in the VBNC state is a prerequisite to ensure the food safety and public health. Despite their nonculturability, VBNC cells have distinct characteristics, such as morphology, metabolism, chemical composition, and gene and protein expression, that have been used as the basis for the development of abundant diagnostic tools. This review covers the current status and advances in various approaches for examining microorganisms in the VBNC state, including but not limited to the methodological aspects, advantages, and drawbacks of each technique. Existing methods, such as direct viable count, SYTO/PI dual staining, and propidium monoazide quantitative polymerase chain reaction (PCR), as well as some techniques with potential to be applied in the future, such as digital PCR, enhanced-surface Raman spectroscopy, and impedance-based techniques, are summarized in depth. Finally, future prospects for the one-step detection of VBNC bacteria are proposed and discussed. We believe that this review can provide more optional methods for researchers and promote the development of rapid, accurate detecting methods, and for inspectors, the diagnostic tools can provide data to undertake risk analysis of VBNC cells.
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Affiliation(s)
- Rui Gao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xinyu Liao
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xihong Zhao
- Research Center for Environmental Ecology and Engineering, Key Laboratory for Green Chemical Process of Ministry of Education, Hubei Key Laboratory of Novel Reactor and Green Chemical Technology, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan, China
| | - Donghong Liu
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
| | - Tian Ding
- Key Laboratory for Agro-Products Postharvest Handling of Ministry of Agriculture, Zhejiang Key Laboratory for Agro-Food Processing, Department of Food Science and Nutrition, Zhejiang University, Hangzhou, Zhejiang, China
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9
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Zhang J, Wang L, Shi L, Chen X, Chen C, Hong Z, Cao Y, Zhao L. Survival strategy of Cronobacter sakazakii against ampicillin pressure: Induction of the viable but nonculturable state. Int J Food Microbiol 2020; 334:108819. [DOI: 10.1016/j.ijfoodmicro.2020.108819] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 07/27/2020] [Accepted: 08/05/2020] [Indexed: 12/18/2022]
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10
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Gautam LK, Sharma P, Capalash N. Attenuation of Acinetobacter baumannii virulence by inhibition of polyphosphate kinase 1 with repurposed drugs. Microbiol Res 2020; 242:126627. [PMID: 33131985 DOI: 10.1016/j.micres.2020.126627] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/27/2020] [Accepted: 10/14/2020] [Indexed: 12/28/2022]
Abstract
Acinetobacter baumannii is clinically one of the most significant pathogens, especially in intensive care settings, because of its multidrug-resistance (MDR). Repurposing of high-affinity drugs is a faster and more plausible approach for combating the emergence of MDR and to tackle bacterial infections. This study was aimed to evaluate the approved drugs potentially inhibiting A. baumannii PPK1 (AbPPK1) mediated synthesis of polyphosphates (polyP). Based on virtual screening, molecular dynamic simulation, and CD spectroscopy for thermal stability, two stable ligands, etoposide and genistein, were found with promising contours for further investigation. Following in vitro inhibition of AbPPK1, the efficacy of selected drugs was further tested against virulence traits of A. baumannii. These drugs significantly reduced the biofilm formation, surface motility in A. baumannii and led to decreased survival under desiccation. In addition to inhibition of PPK1, both drugs increased the expression of polyP degrading enzyme, exopolyphosphatase (PPX), that might be responsible for the decrease in the total cellular polyP. Since polyP modulates the virulence factors in bacteria, destabilization of the polyP pool by these drugs seems particularly striking for their therapeutic applications against A. baumannii.
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Affiliation(s)
- Lalit Kumar Gautam
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Prince Sharma
- Department of Microbiology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India.
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11
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The impact of metal pipe materials, corrosion products, and corrosion inhibitors on antibiotic resistance in drinking water distribution systems. Appl Microbiol Biotechnol 2020; 104:7673-7688. [DOI: 10.1007/s00253-020-10777-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/29/2020] [Accepted: 07/05/2020] [Indexed: 02/07/2023]
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12
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Quantitative detection of viable but nonculturable state Escherichia coli O157:H7 by ddPCR combined with propidium monoazide. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107140] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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13
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Wasfi R, Abdellatif GR, Elshishtawy HM, Ashour HM. First-time characterization of viable but non-culturable Proteus mirabilis: Induction and resuscitation. J Cell Mol Med 2020; 24:2791-2801. [PMID: 32030883 PMCID: PMC7077546 DOI: 10.1111/jcmm.15031] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 11/12/2019] [Accepted: 12/22/2019] [Indexed: 12/11/2022] Open
Abstract
Pathogenic bacteria can enter into a viable but non‐culturable (VBNC) state under unfavourable conditions. Proteus mirabilis is responsible for dire clinical consequences including septicaemia, urinary tract infections and pneumonia, but is not a species previously known to enter VBNC state. We suggested that stress‐induced P. mirabilis can enter a VBNC state in which it retains virulence. P. mirabilis isolates were incubated in extreme osmotic pressure, starvation, low temperature and low pH to induce a VBNC state. Resuscitation was induced by temperature upshift and inoculation in tryptone soy broth with Tween 20 and brain heart infusion broth. Cellular ultrastructure and gene expression were examined using transmission electron microscopy (TEM) and quantitative real‐time polymerase chain reaction (qPCR), respectively. High osmotic pressure and low acidity caused rapid entry into VBNC state. Temperature upshift caused the highest percentage of resuscitation (93%) under different induction conditions. In the VBNC state, cells showed aberrant and dwarf morphology, virulence genes and stress response genes (envZ and rpoS) were expressed (levels varied depending on strain and inducing factors). This is the first‐time characterization of VBNC P. mirabilis. The ability of P. mirabilis pathogenic strains to enter a stress‐induced VBNC state can be a serious public health threat.
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Affiliation(s)
- Reham Wasfi
- Department of Microbiology and Immunology, Faculty of Pharmacy, October University for Modern Sciences and Arts (MSA), Giza, Egypt
| | - Ghada Refaat Abdellatif
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ahram Canadian University (ACU), Giza, Egypt
| | - Hisham Mohamed Elshishtawy
- Microbial Genetics Laboratory, Agricultural Genetic Engineering Research Institute (AGERI), Agricultural Research Center (ARC), Giza, Egypt
| | - Hossam M Ashour
- Department of Biological Sciences, College of Arts and Sciences, University of South Florida St. Petersburg, St. Petersburg, Florida.,Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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14
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Dong K, Pan H, Yang D, Rao L, Zhao L, Wang Y, Liao X. Induction, detection, formation, and resuscitation of viable but non‐culturable state microorganisms. Compr Rev Food Sci Food Saf 2019; 19:149-183. [DOI: 10.1111/1541-4337.12513] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 01/05/2023]
Affiliation(s)
- Kai Dong
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Hanxu Pan
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Dong Yang
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Lei Rao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Liang Zhao
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Yongtao Wang
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
| | - Xiaojun Liao
- Beijing Advanced Innovation Center for Food Nutrition and Human HealthCollege of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- College of Food Science and Nutritional EngineeringChina Agricultural University Beijing China
- Key Lab of Fruit and Vegetable ProcessingMinistry of Agriculture and Rural Affairs Beijing China
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15
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Gautam LK, Sharma P, Capalash N. Bacterial Polyphosphate Kinases Revisited: Role in Pathogenesis and Therapeutic Potential. Curr Drug Targets 2019; 20:292-301. [DOI: 10.2174/1389450119666180801120231] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/02/2018] [Accepted: 07/31/2018] [Indexed: 11/22/2022]
Abstract
Bacterial infections have always been an unrestrained challenge to the medical community due to the rise of multi-drug tolerant and resistant strains. Pioneering work on Escherichia coli polyphosphate kinase (PPK) by Arthur Kornberg has generated great interest in this polyphosphate (PolyP) synthesizing enzyme. PPK has wide distribution among pathogens and is involved in promoting pathogenesis, stress management and susceptibility to antibiotics. Further, the absence of a PPK orthologue in humans makes it a potential drug target. This review covers the functional and structural aspects of polyphosphate kinases in bacterial pathogens. A description of molecules being designed against PPKs has been provided, challenges associated with PPK inhibitor design are highlighted and the strategies to enable development of efficient drug against this enzyme have also been discussed.
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Affiliation(s)
- Lalit Kumar Gautam
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Prince Sharma
- Department of Microbiology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
| | - Neena Capalash
- Department of Biotechnology, Panjab University, BMS Block-I, Sector- 25, Chandigarh, 160014, India
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16
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Ultee E, Ramijan K, Dame RT, Briegel A, Claessen D. Stress-induced adaptive morphogenesis in bacteria. Adv Microb Physiol 2019; 74:97-141. [PMID: 31126537 DOI: 10.1016/bs.ampbs.2019.02.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacteria thrive in virtually all environments. Like all other living organisms, bacteria may encounter various types of stresses, to which cells need to adapt. In this chapter, we describe how cells cope with stressful conditions and how this may lead to dramatic morphological changes. These changes may not only allow harmless cells to withstand environmental insults but can also benefit pathogenic bacteria by enabling them to escape from the immune system and the activity of antibiotics. A better understanding of stress-induced morphogenesis will help us to develop new approaches to combat such harmful pathogens.
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Affiliation(s)
- Eveline Ultee
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Karina Ramijan
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Remus T Dame
- Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands; Macromolecular Biochemistry, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CE Leiden, the Netherlands
| | - Ariane Briegel
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
| | - Dennis Claessen
- Molecular Biotechnology, Institute of Biology, Leiden University, Sylviusweg 72, 2333 BE Leiden, the Netherlands; Centre for Microbial Cell Biology, Leiden University, Leiden, the Netherlands
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17
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Chandrashekhar K, Srivastava V, Hwang S, Jeon B, Ryu S, Rajashekara G. Transducer-Like Protein in Campylobacter jejuni With a Role in Mediating Chemotaxis to Iron and Phosphate. Front Microbiol 2018; 9:2674. [PMID: 30505293 PMCID: PMC6250842 DOI: 10.3389/fmicb.2018.02674] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/19/2018] [Indexed: 01/20/2023] Open
Abstract
Chemotaxis-mediated motility enables Campylobacter jejuni to navigate through complex environmental gradients and colonize diverse niches. C. jejuni is known to possess several methyl accepting chemotaxis proteins (MCPs), also called transducer-like proteins (Tlps). While the role of some of the Tlps in chemotaxis has been identified, their regulation and role in virulence is still not very clear. Here, we investigated the contribution of Tlp2 to C. jejuni chemotaxis, stress survival and colonization of the chicken gastrointestinal tract. The Δtlp2 deletion mutant showed decreased chemotaxis toward aspartate, pyruvate, inorganic phosphate (Pi), and iron (FeSO4). Transcriptional analysis of tlp2 with a promoter fusion reporter assay revealed that the tlp2 promoter (P tlp2 ) was induced by Pi and iron, both in the ferrous (Fe2+) and ferric form (Fe3+). RT-PCR analysis using overlapping primers indicated that the phoX gene, located immediately downstream of tlp2, is co-transcribed with tlp2. A transcription start site was identified at 53 bp upstream of the tlp2 start codon. The Δtlp2 mutant showed decreased colonization of the chicken gastrointestinal tract. Collectively, our findings revealed that the tlp2 plays a role in C. jejuni pathogenesis and colonization in the chicken host and its expression is regulated by iron.
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Affiliation(s)
- Kshipra Chandrashekhar
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, United States
| | - Vishal Srivastava
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, United States
| | - Sunyoung Hwang
- Department of Food and Animal Biotechnology – Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Seoul National University, Seoul, South Korea
| | - Byeonghwa Jeon
- School of Public Health, University of Alberta, Edmonton, AB, Canada
| | - Sangryeol Ryu
- Department of Food and Animal Biotechnology – Department of Agricultural Biotechnology, Center for Agricultural Biomaterials, Seoul National University, Seoul, South Korea
| | - Gireesh Rajashekara
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH, United States
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18
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Relationship between the Viable but Nonculturable State and Antibiotic Persister Cells. J Bacteriol 2018; 200:JB.00249-18. [PMID: 30082460 DOI: 10.1128/jb.00249-18] [Citation(s) in RCA: 143] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacteria have evolved numerous means of survival in adverse environments with dormancy, as represented by "persistence" and the "viable but nonculturable" (VBNC) state, now recognized to be common modes for such survival. VBNC cells have been defined as cells which, induced by some stress, become nonculturable on media that would normally support their growth but which can be demonstrated by various methods to be alive and capable of returning to a metabolically active and culturable state. Persister cells have been described as a population of cells which, while not being antibiotic resistant, are antibiotic tolerant. This drug-tolerant phenotype is thought to be a result of stress-induced and stochastic physiological changes as opposed to mutational events leading to true resistance. In this review, we describe these two dormancy strategies, characterize the molecular underpinnings of each state, and highlight the similarities and differences between them. We believe these survival modes represent a continuum between actively growing and dead cells, with VBNC cells being in a deeper state of dormancy than persister cells.
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19
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Shen Y, Huang PC, Huang C, Sun P, Monroy GL, Wu W, Lin J, Espinosa-Marzal RM, Boppart SA, Liu WT, Nguyen TH. Effect of divalent ions and a polyphosphate on composition, structure, and stiffness of simulated drinking water biofilms. NPJ Biofilms Microbiomes 2018; 4:15. [PMID: 30038792 PMCID: PMC6052100 DOI: 10.1038/s41522-018-0058-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Revised: 05/24/2018] [Accepted: 06/01/2018] [Indexed: 02/04/2023] Open
Abstract
The biofilm chemical and physical properties in engineered systems play an important role in governing pathogen transmission, fouling facilities, and corroding metal surfaces. Here, we investigated how simulated drinking water biofilm chemical composition, structure, and stiffness responded to the common scale control practice of adjusting divalent ions and adding polyphosphate. Magnetomotive optical coherence elastography (MM-OCE), a tool developed for diagnosing diseased tissues, was used to determine biofilm stiffness in this study. MM-OCE, together with atomic force microscopy (AFM), revealed that the biofilms developed from a drinking water source with high divalent ions were stiffer compared to biofilms developed either from the drinking water source with low divalent ions or the water containing a scale inhibitor (a polyphosphate). The higher stiffness of biofilms developed from the water containing high divalent ions was attributed to the high content of calcium carbonate, suggested by biofilm composition examination. In addition, by examining the biofilm structure using optical coherence tomography (OCT), the highest biofilm thickness was found for biofilms developed from the water containing the polyphosphate. Compared to the stiff biofilms developed from the water containing high divalent ions, the soft and thick biofilms developed from the water containing polyphosphate will be expected to have higher detachment under drinking water flow. This study suggested that water chemistry could be used to predict the biofilm properties and subsequently design the microbial safety control strategies. A variety of analytical techniques are revealing the complex influences of ions in drinking water supplies on the structure of biofilms. Such biofilms often contaminate water supply pipes and machinery. Yun Shen and colleagues at the University of Illinois at Urbana-Champaign in the USA investigated the effects of ions with a double positive charge – ‘divalent cations’ – and polyphosphate ions. Divalent cations, especially calcium and magnesium ions, are abundant in drinking water in many regions, promoting the formation of limescale deposits. Polyphosphates are commonly added to water supplies to reduce limescale formation, inhibit corrosion and discourage biofilm formation. The research revealed that divalent cations increase biofilm stiffness, while polyphosphates promote softer but thicker biofilms that are more easily removed. The results will help optimize water treatment procedures to control both microbial contamination and limescale problems.
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Affiliation(s)
- Yun Shen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,4Present Address: University of Michigan, 1351 Beal Ave., 219 EWRE Bldg, Ann Arbor, MI 48109-2125 USA
| | - Pin Chieh Huang
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Conghui Huang
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Peng Sun
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Guillermo L Monroy
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wenjing Wu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Jie Lin
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Rosa M Espinosa-Marzal
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Stephen A Boppart
- 2Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL USA.,3Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Wen-Tso Liu
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Thanh H Nguyen
- 1Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL USA
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20
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Polyphosphate-Accumulating Bacteria: Potential Contributors to Mineral Dissolution in the Oral Cavity. Appl Environ Microbiol 2018; 84:AEM.02440-17. [PMID: 29352083 PMCID: PMC5861820 DOI: 10.1128/aem.02440-17] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/11/2018] [Indexed: 01/08/2023] Open
Abstract
Bacteria that accumulate polyphosphates have previously been shown to dynamically influence the solubility of phosphatic minerals in marine settings and wastewater. Here, we show that dental plaque, saliva, and carious lesions all contain abundant polyphosphate-accumulating bacteria. Saturation state modeling results, informed by phosphate uptake experiments using the model organism Lactobacillus rhamnosus, which is known to inhabit advanced carious lesions, suggest that polyphosphate accumulation can lead to undersaturated conditions with respect to hydroxyapatite under some oral cavity conditions. The cell densities of polyphosphate-accumulating bacteria we observed in some regions of oral biofilms are comparable to those that produce undersaturated conditions (i.e., those that thermodynamically favor mineral dissolution) in our phosphate uptake experiments with L. rhamnosus These results suggest that the localized generation of undersaturated conditions by polyphosphate-accumulating bacteria constitutes a new potential mechanism of tooth dissolution that may augment the effects of metabolic acid production.IMPORTANCE Dental caries is a serious public health issue that can have negative impacts on overall quality of life and oral health. The role of oral bacteria in the dissolution of dental enamel and dentin that can result in carious lesions has long been solely ascribed to metabolic acid production. Here, we show that certain oral bacteria may act as a dynamic shunt for phosphate in dental biofilms via the accumulation of a polymer known as polyphosphate-potentially mediating phosphate-dependent conditions such as caries (dental decay).
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21
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Studying the Phenotypic and Genotypic Expression of Antibiotic Resistance in Campylobacter jejuni under Stress Conditions. Bull Exp Biol Med 2018; 164:466-472. [PMID: 29504101 DOI: 10.1007/s10517-018-4014-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Indexed: 10/17/2022]
Abstract
Specific features for the development of resistance in Campylobacter jejuni strains were studied after treatment with antibiotics of 6 pharmacological groups. Populations of 18 native strains of C. jejuni (isolated from raw poultry products) and their subcultures (obtained after 2-3-fold stress exposures to antimicrobial agents in subinhibitory doses) were examined to evaluate the expression of phenotypic antibiotic resistance. Genotypic properties of strains were studied by the PCR with primers that detect the presence of genes for resistance to aminoglycosides (aphA-1, aphA-3, and aphA-7), tetracyclines (tetO), and quinolones (GZgyrA). The majority of test strains of C. jejuni exhibited a high resistance to nalidixic acid, ciprofloxacin, and tetracycline, which reached the maximum value after numerous passages. The expression of antibiotic resistance was greatest in the presence of nalidixic acid and tetracycline. Ciprofloxacin resistance of 33% strains, which were initially resistant to this antibiotic, was increased after 2-3-fold treatment. We revealed a high degree of correspondence between phenotypic and genotypic profiles of antibiotic resistance in food isolates of Campylobacter. One, two, or more genes of aphA were identified in 85% strains phenotypically resistant to aminoglycosides. The tetO gene was found nearly in all strains resistant to tetracycline. Studying the biofilm matrix in C. jejuni after culturing with antibiotics in subinhibitory doses showed that quinolones (particularly nalidixic acid) and tetracyclines potentiate the formation of biofilms and increase the tolerance of Campylobacter to stress exposures. The intensity of biofilm growth was shown to depend little on the effect of macrolides and aminoglycosides. Therefore, the presence of these agents in residual concentrations is associated with a lower risk for the development of antibiotic resistance in C. jejuni populations.
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22
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Nosho K, Fukushima H, Asai T, Nishio M, Takamaru R, Kobayashi-Kirschvink KJ, Ogawa T, Hidaka M, Masaki H. cAMP-CRP acts as a key regulator for the viable but non-culturable state in Escherichia coli. MICROBIOLOGY-SGM 2018; 164:410-419. [PMID: 29458560 DOI: 10.1099/mic.0.000618] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
A variety of bacteria, including Escherichia coli, are known to enter the viable but non-culturable (VBNC) state under various stress conditions. During this state, cells lose colony-forming activities on conventional agar plates while retaining signs of viability. Diverse environmental stresses including starvation induce the VBNC state. However, little is known about the genetic mechanism inducing this state. Here, we aimed to reveal the genetic determinants of the VBNC state of E. coli. We hypothesized that the VBNC state is a process wherein specific gene products important for colony formation are depleted during the extended period of stress conditions. If so, higher expression of these genes would maintain colony-forming activities, thereby restraining cells from entering the VBNC state. From an E. coli plasmid-encoded ORF library, we identified genes that were responsible for maintaining high colony-forming activities after exposure to starvation condition. Among these, cpdA encoding cAMP phosphodiesterase exhibited higher performance in the maintenance of colony-forming activities. As cpdA overexpression decreases intracellular cAMP, cAMP or its complex with cAMP-receptor protein (CRP) may negatively regulate colony-forming activities under stress conditions. We confirmed this using deletion mutants lacking adenylate cyclase or CRP. These mutants fully maintained colony-forming activities even after a long period of starvation, while wild-type cells lost most of this activity. Thus, we concluded that the lack of cAMP-CRP effectively retains high colony-forming activities, indicating that cAMP-CRP acts as a positive regulator necessary for the induction of the VBNC state in E. coli.
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Affiliation(s)
- Kazuki Nosho
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Hiroko Fukushima
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Takehiro Asai
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Masahiro Nishio
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Reiko Takamaru
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | | | - Tetsuhiro Ogawa
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Makoto Hidaka
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
| | - Haruhiko Masaki
- Department of Biotechnology, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo, Japan
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23
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Bronowski C, Mustafa K, Goodhead I, James CE, Nelson C, Lucaci A, Wigley P, Humphrey TJ, Williams NJ, Winstanley C. Campylobacter jejuni transcriptome changes during loss of culturability in water. PLoS One 2017; 12:e0188936. [PMID: 29190673 PMCID: PMC5708674 DOI: 10.1371/journal.pone.0188936] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 11/15/2017] [Indexed: 12/21/2022] Open
Abstract
Background Water serves as a potential reservoir for Campylobacter, the leading cause of bacterial gastroenteritis in humans. However, little is understood about the mechanisms underlying variations in survival characteristics between different strains of C. jejuni in natural environments, including water. Results We identified three Campylobacter jejuni strains that exhibited variability in their ability to retain culturability after suspension in tap water at two different temperatures (4°C and 25°C). Of the three, strains C. jejuni M1 exhibited the most rapid loss of culturability whilst retaining viability. Using RNAseq transcriptomics, we characterised C. jejuni M1 gene expression in response to suspension in water by analyzing bacterial suspensions recovered immediately after introduction into water (Time 0), and from two sampling time/temperature combinations where considerable loss of culturability was evident, namely (i) after 24 h at 25°C, and (ii) after 72 h at 4°C. Transcript data were compared with a culture-grown control. Some gene expression characteristics were shared amongst the three populations recovered from water, with more genes being up-regulated than down. Many of the up-regulated genes were identified in the Time 0 sample, whereas the majority of down-regulated genes occurred in the 25°C (24 h) sample. Conclusions Variations in expression were found amongst genes associated with oxygen tolerance, starvation and osmotic stress. However, we also found upregulation of flagellar assembly genes, accompanied by down-regulation of genes involved in chemotaxis. Our data also suggested a switch from secretion via the sec system to via the tat system, and that the quorum sensing gene luxS may be implicated in the survival of strain M1 in water. Variations in gene expression also occurred in accessory genome regions. Our data suggest that despite the loss of culturability, C. jejuni M1 remains viable and adapts via specific changes in gene expression.
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Affiliation(s)
- Christina Bronowski
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Kasem Mustafa
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Ian Goodhead
- School of Environment and Life Sciences, University of Salford, Salford, United Kingdom
| | - Chloe E. James
- School of Environment and Life Sciences, University of Salford, Salford, United Kingdom
| | - Charlotte Nelson
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Anita Lucaci
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Paul Wigley
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Tom J. Humphrey
- Medical Microbiology and Infectious Diseases, School of Medicine, Swansea University, Swansea, United Kingdom
| | - Nicola J. Williams
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
| | - Craig Winstanley
- Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom
- * E-mail:
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24
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Nev OA, Van Den Berg HA. Mathematical models of microbial growth and metabolism: a whole-organism perspective. Sci Prog 2017; 100:343-362. [PMID: 29113620 PMCID: PMC10365175 DOI: 10.3184/003685017x15063357842583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We review the principles underpinning the development of mathematical models of the metabolic activities of micro-organisms. Such models are important to understand and chart the substantial contributions made by micro-organisms to geochemical cycles, and also to optimise the performance of bioreactors that exploit the biochemical capabilities of these organisms. We advocate an approach based on the principle of dynamic allocation. We survey the biological background that motivates this approach, including nutrient assimilation, the regulation of gene expression, and the principles of microbial growth. In addition, we discuss the classic models of microbial growth as well as contemporary approaches. The dynamic allocation theory generalises these classic models in a natural manner and is readily amenable to the additional information provided by transcriptomics and proteomics approaches. Finally, we touch upon these organising principles in the context of the transition from the free-living unicellular mode of life to multicellularity.
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25
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Kassem II, Helmy YA, Kathayat D, Candelero-Rueda RA, Kumar A, Deblais L, Huang HC, Sahin O, Zhang Q, Rajashekara G. Nonculturability Might Underestimate the Occurrence of Campylobacter in Broiler Litter. Foodborne Pathog Dis 2017. [PMID: 28622473 DOI: 10.1089/fpd.2017.2279] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
We investigated the contribution of litter to the occurrence of Campylobacter on three broiler farms, which were known to have low (LO) and high (HI-A and HI-B) Campylobacter prevalence. For this purpose, we collected litter samples (n = 288) during and after two rearing cycles from each farm. We evaluated the occurrence of Campylobacter (using selective enrichment and quantitative real-time polymerase chain reaction [q-PCR] analysis) in the litter samples as well as the litter's pH and moisture content. Ceca from each flock (n = 144) were harvested at slaughter age and used to quantify Campylobacter colony-forming units (CFUs). Campylobacter was only retrieved from 7 litter samples that were collected from HI-A and HI-B during the growing period, but no Campylobacter was isolated from LO farms. The q-PCR analysis detected Campylobacter in pooled litter samples from all three farms. However, in litter collected during the same rotation, Campylobacter levels were significantly higher (p < 0.05) in HI-A and HI-B litter samples in comparison to those in LO. Cecal samples from HI-A and HI-B yielded relatively high numbers of Campylobacter CFUs, which were undetectable in LO samples. Litter's pH and moisture did not affect the overall occurrence of Campylobacter in litter and ceca on any of the farms. Our data suggest that Campylobacter was generally more abundant in litter that was collected from farms with highly colonized flocks. Therefore, better approaches for assessing the occurrence of Campylobacter in litter might be warranted in order to reduce the dissemination of these pathogens on and off poultry farms.
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Affiliation(s)
- Issmat I Kassem
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio.,2 Department of Nutrition and Food Sciences, Faculty of Agricultural and Food Sciences, American University of Beirut , Beirut, Lebanon
| | - Yosra A Helmy
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Dipak Kathayat
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Rosario A Candelero-Rueda
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Anand Kumar
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Loic Deblais
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Huang-Chi Huang
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
| | - Orhan Sahin
- 3 Department of Veterinary Microbiology, Iowa State University , VMPM/1130 Veterinary Medicine, Ames, Iowa
| | - Qijing Zhang
- 3 Department of Veterinary Microbiology, Iowa State University , VMPM/1130 Veterinary Medicine, Ames, Iowa
| | - Gireesh Rajashekara
- 1 Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University , Wooster, Ohio
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26
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Kassem II, Candelero-Rueda RA, Esseili KA, Rajashekara G. Formate simultaneously reduces oxidase activity and enhances respiration in Campylobacter jejuni. Sci Rep 2017; 7:40117. [PMID: 28091524 PMCID: PMC5238407 DOI: 10.1038/srep40117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2016] [Accepted: 12/02/2016] [Indexed: 02/06/2023] Open
Abstract
The foodborne microaerophilic pathogen, Campylobacter jejuni, possesses a periplasmic formate dehydrogenase and two terminal oxidases, which serve to metabolize formate and facilitate the use of oxygen as a terminal electron acceptor, respectively. Formate, a primary energy source for C. jejuni, inhibits oxidase activity in other bacteria. Here, we hypothesized that formate might affect both energy metabolism and microaerobic survival in C. jejuni. Subsequently, we showed that C. jejuni 81–176 (wildtype) exhibited enhanced chemoattraction to and respiration of formate in comparison to other organic acids. Formate also significantly increased C. jejuni’s growth, motility, and biofilm formation under microaerobic (5% O2) conditions. However, formate reduced oxidase activity under microaerobic conditions as well as aerotolerance and biofilm formation under ambient oxygen conditions. The expression of genes encoding the ribonucleotide reductase (RNR) and proteins that facilitate the use of alternative electron acceptors generally increased in the presence of formate. Taken together, formate might play a role in optimizing C. jejuni’s adaptation to the oxygen-limited gastrointestinal tract of the host. By affecting oxidase activity, formate possibly facilitates shuttling electrons to alternative acceptors, while likely conserving limited oxygen concentrations for other essential functions such as DNA synthesis via RNR which is required for C. jejuni’s growth.
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Affiliation(s)
- Issmat I Kassem
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
| | - Rosario A Candelero-Rueda
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
| | - Kawthar A Esseili
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
| | - Gireesh Rajashekara
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
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Kumar A, Gangaiah D, Torrelles JB, Rajashekara G. Polyphosphate and associated enzymes as global regulators of stress response and virulence in Campylobacter jejuni. World J Gastroenterol 2016; 22:7402-7414. [PMID: 27672264 PMCID: PMC5011657 DOI: 10.3748/wjg.v22.i33.7402] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 06/03/2016] [Accepted: 07/21/2016] [Indexed: 02/06/2023] Open
Abstract
Campylobacter jejuni (C. jejuni), a Gram-negative microaerophilic bacterium, is a predominant cause of bacterial foodborne gastroenteritis in humans worldwide. Despite its importance as a major foodborne pathogen, our understanding of the molecular mechanisms underlying C. jejuni stress survival and pathogenesis is limited. Inorganic polyphosphate (poly P) has been shown to play significant roles in bacterial resistance to stress and virulence in many pathogenic bacteria. C. jejuni contains the complete repertoire of enzymes required for poly P metabolism. Recent work in our laboratory and others have demonstrated that poly P controls a plethora of C. jejuni properties that impact its ability to survive in the environment as well as to colonize/infect mammalian hosts. This review article summarizes the current literature on the role of poly P in C. jejuni stress survival and virulence and discusses on how poly P-related enzymes can be exploited for therapeutic/prevention purposes. Additionally, the review article identifies potential areas for future investigation that would enhance our understanding of the role of poly P in C. jejuni and other bacteria, which ultimately would facilitate design of effective therapeutic/preventive strategies to reduce not only the burden of C. jejuni-caused foodborne infections but also of other bacterial infections in humans.
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28
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Polyphosphate kinases modulate Campylobacter jejuni outer membrane constituents and alter its capacity to invade and survive in intestinal epithelial cells in vitro. Emerg Microbes Infect 2015; 4:e77. [PMID: 26714783 PMCID: PMC4715166 DOI: 10.1038/emi.2015.77] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 09/28/2015] [Accepted: 10/01/2015] [Indexed: 12/12/2022]
Abstract
Campylobacter jejuni is the most prevalent cause of bacterial gastroenteritis worldwide. Polyphosphate kinases 1 and 2 (PPK1 and PPK2) regulate several cellular processes, including the biosynthesis of the bacterial cell wall. Despite their importance, whether PPK1 and PPK2 modulate the composition of C. jejuni outer membrane constituents (OMCs) and consequently impact its interaction with host cells remains unknown. Our comparative analysis between C. jejuni wild type, Δppk1, and Δppk2 strains showed qualitative and quantitative differences in the total OMC composition among these strains. Importantly, these OMC variations observed on the C. jejuni polyphosphate kinase mutants are directly related to their capacity to invade, survive, and alter the immune response of intestinal epithelial cells in vitro. Specifically, sub-fractionation of the C. jejuni OMC indicated that OMC proteins are uniquely associated with bacterial invasion, whereas C. jejuni OMC proteins, lipids, and lipoglycans are all associated with C. jejuni intracellular survival. This study provides new insights regarding the function of polyphosphate kinases and their role in C. jejuni infection.
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Chandrashekhar K, Kassem II, Nislow C, Gangaiah D, Candelero-Rueda RA, Rajashekara G. Transcriptome analysis of Campylobacter jejuni polyphosphate kinase (ppk1 and ppk2) mutants. Virulence 2015; 6:814-8. [PMID: 26537695 DOI: 10.1080/21505594.2015.1104449] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Affiliation(s)
- Kshipra Chandrashekhar
- a Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine ; The Ohio State University ; Wooster , OH , USA
| | - Issmat I Kassem
- a Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine ; The Ohio State University ; Wooster , OH , USA
| | - Corey Nislow
- b Department of Pharmaceutical Sciences ; University of British Columbia ; Vancouver , BC Canada
| | - Dharanesh Gangaiah
- a Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine ; The Ohio State University ; Wooster , OH , USA
| | - Rosario A Candelero-Rueda
- a Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine ; The Ohio State University ; Wooster , OH , USA
| | - Gireesh Rajashekara
- a Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine ; The Ohio State University ; Wooster , OH , USA
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Chandrashekhar K, Gangaiah D, Pina-Mimbela R, Kassem II, Jeon BH, Rajashekara G. Transducer like proteins of Campylobacter jejuni 81-176: role in chemotaxis and colonization of the chicken gastrointestinal tract. Front Cell Infect Microbiol 2015; 5:46. [PMID: 26075188 PMCID: PMC4444964 DOI: 10.3389/fcimb.2015.00046] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 05/11/2015] [Indexed: 01/06/2023] Open
Abstract
Transducer Like Proteins (Tlps), also known as methyl accepting chemotaxis proteins (MCP), enable enteric pathogens to respond to changing nutrient levels in the environment by mediating taxis toward or away from specific chemoeffector molecules. Despite recent advances in the characterization of chemotaxis responses in Campylobacter jejuni, the impact of Tlps on the adaptation of this pathogen to disparate niches and hosts is not fully characterized. The latter is particularly evident in the case of C. jejuni 81-176, a strain that is known to be highly invasive. Furthermore, the cytoplasmic group C Tlps (Tlp5, 6, and 8) were not extensively evaluated. Here, we investigated the role of C. jejuni 81-176 Tlps in chemotaxis toward various substrates, biofilm formation, in vitro interaction with human intestinal cells, and chicken colonization. We found that the Δtlp6 and Δtlp10 mutants exhibited decreased chemotaxis toward aspartate, whereas the Δtlp6 mutant displayed a decreased chemotaxis toward Tri-Carboxylic Acid (TCA) cycle intermediates such as pyruvate, isocitrate, and succinate. Our findings also corroborated that more than one Tlp is involved in mediating chemotaxis toward the same nutrient. The deletion of tlps affected important phenotypes such as motility, biofilm formation, and invasion of human intestinal epithelial cells (INT-407). The Δtlp8 mutant displayed increased motility in soft agar and showed decreased biofilm formation. The Δtlp8 and Δtlp9 mutants were significantly defective in invasion in INT-407 cells. The Δtlp10 mutant was defective in colonization of the chicken proximal and distal gastrointestinal tract, while the Δtlp6 and Δtlp8 mutants showed reduced colonization of the duodenum and jejunum. Our results highlight the importance of Tlps in C. jejuni's adaptation and pathobiology.
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Affiliation(s)
- Kshipra Chandrashekhar
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA
| | - Dharanesh Gangaiah
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA
| | - Ruby Pina-Mimbela
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA
| | - Issmat I Kassem
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA
| | - Byeong H Jeon
- Department of Environmental Health Sciences, School of Public Health, University of Alberta Edmonton, AB, Canada
| | - Gireesh Rajashekara
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research Development Center, The Ohio State University Wooster, OH, USA
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Oh E, McMullen L, Jeon B. Impact of oxidative stress defense on bacterial survival and morphological change in Campylobacter jejuni under aerobic conditions. Front Microbiol 2015; 6:295. [PMID: 25914692 PMCID: PMC4392298 DOI: 10.3389/fmicb.2015.00295] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Accepted: 03/25/2015] [Indexed: 11/30/2022] Open
Abstract
Campylobacter jejuni, a microaerophilic foodborne pathogen, inescapably faces high oxygen tension during its transmission to humans. Thus, the ability of C. jejuni to survive under oxygen-rich conditions may significantly impact C. jejuni viability in food and food safety as well. In this study, we investigated the impact of oxidative stress resistance on the survival of C. jejuni under aerobic conditions by examining three mutants defective in key antioxidant genes, including ahpC, katA, and sodB. All the three mutants exhibited growth reduction under aerobic conditions compared to the wild-type (WT), and the ahpC mutant showed the most significant growth defect. The CFU reduction in the mutants was recovered to the WT level by complementation. Higher levels of reactive oxygen species were accumulated in C. jejuni under aerobic conditions than microaerobic conditions, and supplementation of culture media with an antioxidant recovered the growth of C. jejuni. The levels of lipid peroxidation and protein oxidation were significantly increased in the mutants compared to WT. Additionally, the mutants exhibited different morphological changes under aerobic conditions. The ahpC and katA mutants developed coccoid morphology by aeration, whereas the sodB mutant established elongated cellular morphology. Compared to microaerobic conditions, interestingly, aerobic culture conditions substantially induced the formation of coccoidal cells, and antioxidant treatment reduced the emergence of coccoid forms under aerobic conditions. The ATP concentrations and PMA–qPCR analysis supported that oxidative stress is a factor that induces the development of a viable-but-non-culturable state in C. jejuni. The findings in this study clearly demonstrated that oxidative stress resistance plays an important role in the survival and morphological changes of C. jejuni under aerobic conditions.
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Affiliation(s)
- Euna Oh
- School of Public Health, University of Alberta, Edmonton, AB Canada
| | - Lynn McMullen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB Canada
| | - Byeonghwa Jeon
- School of Public Health, University of Alberta, Edmonton, AB Canada
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Campylobacter jejuni biofilm cells become viable but non-culturable (VBNC) in low nutrient conditions at 4 °C more quickly than their planktonic counterparts. Food Control 2015. [DOI: 10.1016/j.foodcont.2014.08.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Drozd M, Chandrashekhar K, Rajashekara G. Polyphosphate-mediated modulation of Campylobacter jejuni biofilm growth and stability. Virulence 2015; 5:680-90. [PMID: 25127528 DOI: 10.4161/viru.34348] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Biofilms increase C. jejuni's resilience to detergents, antibiotics, and environmental stressors. In these investigations, we studied the modulation of biofilm in response to phosphate related stressors. We found that the deletion of ppk1, phoX, and ppk2 (polyphosphate associated [poly P] genes) in C. jejuni modulated different stages of biofilm formation such as attached microcolonies, air-liquid biofilms, and biofilm shedding. Additionally, inorganic phosphate also modulated attached microcolonies, air-liquid biofilms, and biofilm shedding both independently of and additively in the poly P associated mutants. Furthermore, we observed that these different biofilm stages were affected by biofilm age: for example, the adherent microcolonies were maximum on day 2, while biofilm growth at the air-liquid interface and shedding was highest on day 3. Also, we observed altered calcofluor white reactive polysaccharides in poly P-associated mutants, as well as increased secretion of autoinducer-2 (AI-2) quorum sensing molecules in the ∆ppk2 mutant. Further, the polysaccharide and flagellar biosynthesis genes, that are associated with biofilm formation, were altered in these poly P-associated mutants. We conclude that the phosphate limiting condition modulates C. jejuni biofilm formation.
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Affiliation(s)
- Mary Drozd
- Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine; The Ohio State University; Wooster, OH USA
| | - Kshipra Chandrashekhar
- Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine; The Ohio State University; Wooster, OH USA
| | - Gireesh Rajashekara
- Food Animal Health Research Program; Ohio Agricultural Research and Development Center; Department of Veterinary Preventive Medicine; The Ohio State University; Wooster, OH USA
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Ayrapetyan M, Williams TC, Oliver JD. Bridging the gap between viable but non-culturable and antibiotic persistent bacteria. Trends Microbiol 2014; 23:7-13. [PMID: 25449050 DOI: 10.1016/j.tim.2014.09.004] [Citation(s) in RCA: 186] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/17/2014] [Accepted: 09/19/2014] [Indexed: 11/25/2022]
Abstract
Microbial dormancy is a widespread phenomenon employed by bacteria to evade environmental threats including antibiotics. This intrinsic mechanism of antibiotic tolerance has drawn special attention to the role of dormancy in human disease, particularly in regards to recurrent infections. Two dormancy states, the viable but non-culturable state and bacterial persistence, both produce antibiotic-tolerant populations capable of withstanding prolonged lethal treatment. Currently described as two distinct forms of dormancy, they are rarely discussed in the same context. We argue here that these two dormant states are closely related phenomena which are part of a shared 'dormancy continuum'. This discussion is intended to stimulate discourse about these seemingly different but very similar dormant states.
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Affiliation(s)
- Mesrop Ayrapetyan
- Department of Biological Sciences, The University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
| | - Tiffany C Williams
- Department of Biological Sciences, The University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
| | - James D Oliver
- Department of Biological Sciences, The University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA.
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Müller A, Beeby M, McDowall AW, Chow J, Jensen GJ, Clemons WM. Ultrastructure and complex polar architecture of the human pathogen Campylobacter jejuni. Microbiologyopen 2014; 3:702-10. [PMID: 25065852 PMCID: PMC4234261 DOI: 10.1002/mbo3.200] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Revised: 06/17/2014] [Accepted: 06/27/2014] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni is one of the most successful food-borne human pathogens. Here we use electron cryotomography to explore the ultrastructure of C. jejuni cells in logarithmically growing cultures. This provides the first look at this pathogen in a near-native state at macromolecular resolution (~5 nm). We find a surprisingly complex polar architecture that includes ribosome exclusion zones, polyphosphate storage granules, extensive collar-shaped chemoreceptor arrays, and elaborate flagellar motors.
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Affiliation(s)
- Axel Müller
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 E. California Blvd., Pasadena, California, 91125
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36
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Bronowski C, James CE, Winstanley C. Role of environmental survival in transmission of Campylobacter jejuni. FEMS Microbiol Lett 2014; 356:8-19. [PMID: 24888326 DOI: 10.1111/1574-6968.12488] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/20/2014] [Accepted: 05/24/2014] [Indexed: 11/29/2022] Open
Abstract
Campylobacter species are the most common cause of bacterial gastroenteritis, with C. jejuni responsible for the majority of these cases. Although it is clear that livestock, and particularly poultry, are the most common source, it is likely that the natural environment (soil and water) plays a key role in transmission, either directly to humans or indirectly via farm animals. It has been shown using multilocus sequence typing that some clonal complexes (such as ST-45) are more frequently isolated from environmental sources such as water, suggesting that strains vary in their ability to survive in the environment. Although C. jejuni are fastidious microaerophiles generally unable to grow in atmospheric levels of oxygen, C. jejuni can adapt to survival in the environment, exhibiting aerotolerance and starvation survival. Biofilm formation, the viable but nonculturable state, and interactions with other microorganisms can all contribute to survival outside the host. By exploiting high-throughput technologies such as genome sequencing and RNA Seq, we are well placed to decipher the mechanisms underlying the variations in survival between strains in environments such as soil and water and to better understand the role of environmental persistence in the transmission of C. jejuni directly or indirectly to humans.
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Affiliation(s)
- Christina Bronowski
- Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
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37
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Malde A, Gangaiah D, Chandrashekhar K, Pina-Mimbela R, Torrelles JB, Rajashekara G. Functional characterization of exopolyphosphatase/guanosine pentaphosphate phosphohydrolase (PPX/GPPA) of Campylobacter jejuni. Virulence 2014; 5:521-33. [PMID: 24569519 DOI: 10.4161/viru.28311] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The inorganic polyphosphate (poly-P) is a key regulator of stress responses and virulence in many bacterial pathogens including Campylobacter jejuni. The role of exopolyphosphatases/guanosine pentaphosphate (pppGpp) phosphohydrolases (PPX/GPPA) in poly-P homeostasis and C. jejuni pathobiology remains unexplored. Here, we analyzed deletion mutants (∆ppx1, ∆ppx2) and the double knockout mutant (dkppx), all ∆ppx mutants exhibited increased capacity to accumulate poly-P; however only ∆ppx1 and dkppx mutants showed decreased accumulation of ppGpp, an alarmone molecule that regulates stringent response in bacteria, suggesting potential dual role for PPX1/GPPA. Nutrient survival defect of ∆ppx mutants was rescued by the supplementation of specific amino acids implying that survival defect may be associated with decreased ppGpp and/ or increased poly-P in ∆ppx mutants. The ppk1 and spoT were upregulated in both ∆ppx1 and ∆ppx2 suggesting a compensatory role for SpoT and Ppk1 in poly-P and ppGpp homeostasis. The lack of ppx genes resulted in defects in motility, biofilm formation, nutrient stress survival, invasion and intracellular survival indicating that maintaining a certain level of poly-P is critical for ppx genes in C. jejuni pathophysiology. Both ppx1 and ppx2 mutants were resistant to human complement-mediated killing; however, the dkppx mutant was sensitive. The serum susceptibility did not occur in the presence of MgCl 2 and EGTA suggesting an involvement of the classical or lectin pathway of complement mediated killing. Interestingly, the chicken serum did not have any effect on the ∆ppx mutants' survival. The observed serum susceptibility was not related to C. jejuni surface capsule and lipooligosaccharide structures. Our study underscores the importance of PPX/GPPA proteins in poly-P and ppGpp homeostasis, two critical molecules that modulate environmental stress responses and virulence in C. jejuni.
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Affiliation(s)
- Anandkumar Malde
- Food Animal Health Research Program; Department of Veterinary Preventive Medicine; College of Veterinary Medicine; The Ohio State University; Wooster, OH USA
| | - Dharanesh Gangaiah
- Food Animal Health Research Program; Department of Veterinary Preventive Medicine; College of Veterinary Medicine; The Ohio State University; Wooster, OH USA
| | - Kshipra Chandrashekhar
- Food Animal Health Research Program; Department of Veterinary Preventive Medicine; College of Veterinary Medicine; The Ohio State University; Wooster, OH USA
| | - Ruby Pina-Mimbela
- Food Animal Health Research Program; Department of Veterinary Preventive Medicine; College of Veterinary Medicine; The Ohio State University; Wooster, OH USA
| | - Jordi B Torrelles
- Department of Microbial Infection and Immunity; Center for Microbial Interface Biology; The Ohio State University; Columbus, OH USA
| | - Gireesh Rajashekara
- Food Animal Health Research Program; Department of Veterinary Preventive Medicine; College of Veterinary Medicine; The Ohio State University; Wooster, OH USA
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Pinto D, Santos MA, Chambel L. Thirty years of viable but nonculturable state research: unsolved molecular mechanisms. Crit Rev Microbiol 2013; 41:61-76. [PMID: 23848175 DOI: 10.3109/1040841x.2013.794127] [Citation(s) in RCA: 200] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Viable but nonculturable (VBNC) cells were recognized 30 years ago; and despite decades of research on the topic, most results are disperse and apparently incongruous. Since its description, a huge controversy arose regarding the ecological significance of this state: is it a degradation process without real significance for bacterial life cycles or is it an adaptive strategy of bacteria to cope with stressful conditions? In order to solve the molecular mechanisms of VBNC state induction and resuscitation, researchers in the field must be aware and overcome common issues delaying research progress. In this review, we discuss the intrinsic characteristic features of VBNC cells, the first clues on what is behind the VBNC state's induction, the models proposed for their resuscitation and the current methods to prove not only that cells are in VBNC state but also that they are able to resuscitate.
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Affiliation(s)
- Daniela Pinto
- Center for Biodiversity, Functional and Integrative Genomics (BioFIG), Faculty of Sciences, University of Lisbon , Lisbon , Portugal
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Kassem II, Chandrashekhar K, Rajashekara G. Of energy and survival incognito: a relationship between viable but non-culturable cells formation and inorganic polyphosphate and formate metabolism in Campylobacter jejuni. Front Microbiol 2013; 4:183. [PMID: 23847606 PMCID: PMC3705167 DOI: 10.3389/fmicb.2013.00183] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/18/2013] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni is a Gram-negative food-borne bacterium that can cause mild to serious diseases in humans. A variety of stress conditions including exposure to formic acid, a weak organic acid, can cause C. jejuni to form viable but non-culturable cells (VBNC), which was proposed as a potential survival mechanism. The inability to detect C. jejuni VBNC using standard culturing techniques may increase the risk of exposure to foods contaminated with this pathogen. However, little is known about the cellular mechanisms and triggers governing VBNC formation. Here, we discuss novel mechanisms that potentially affect VBNC formation in C. jejuni and emphasize the impact of formic acid on this process. Specifically, we highlight findings that show that impairing inorganic polyphosphate (poly-P) metabolism reduces the ability of C. jejuni to form VBNC in a medium containing formic acid. We also discuss the potential effect of poly-P and formate metabolism on energy homeostasis and cognate VBNC formation. The relationship between poly-P metabolism and VBNC formation under acid stress has only recently been identified and may represent a breakthrough in understanding this phenomenon and its impact on food safety.
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Affiliation(s)
- Issmat I Kassem
- Food Animal Health Research Program, Ohio Agricultural Research and Development Center, Department of Veterinary Preventive Medicine, The Ohio State University Wooster, OH, USA
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Chopra S, Ramkissoon K, Anderson DC. A systematic quantitative proteomic examination of multidrug resistance in Acinetobacter baumannii. J Proteomics 2013; 84:17-39. [PMID: 23542354 DOI: 10.1016/j.jprot.2013.03.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 02/18/2013] [Accepted: 03/17/2013] [Indexed: 12/29/2022]
Abstract
UNLABELLED Multidrug-resistant Acinetobacter baumannii strains have been examined at the DNA sequence level, but seldom using large-scale quantitative proteomics. We have compared the proteome of the multidrug resistant strain BAA-1605, with the proteome of the drug-sensitive strain ATCC 17978, using iTRAQ labeling and online 2D LC/MS/MS for peptide/protein identification. Of 1484 proteins present in at least 2 of 4 independent experiments, 114 are 2-fold to 66-fold more abundant in BAA-1605, and 99 are 2-fold to 50-fold less abundant. Proteins with 2-fold or greater abundance in the multidrug resistant strain include drug-, antibiotic-, and heavy metal-resistance proteins, stress-related proteins, porins, membrane transporters, proteins important for acquisition of foreign DNA, biofilm-related proteins, cell-wall and exopolysaccharide-related proteins, lipoproteins, metabolic proteins, and many with no annotated function. The porin CarO, inactivated in carbapenem-resistant strains, is 2.3-fold more abundant in BAA-1605. Likewise, the porin OmpW, less abundant in carbapenem- and colistin-resistant A. baumannii strains, is 3-fold more abundant in BAA-1605. Nine proteins, all present in the drug-sensitive strain but from 2.2-fold to 16-fold more abundant in the MDR strain, can potentially account for the observed resistance of BAA-1605 to 18 antibiotics. BIOLOGICAL SIGNIFICANCE Multidrug resistant (MDR) strains of the pathogen Acinetobacter baumannii are a significant cause of hospital-acquired infections, are associated with increased mortality and length of stay, and may be a major factor underlying the spread of this pathogen, which is difficult to eradicate from clinical settings. To obtain a better understanding of antimicrobial resistance mechanisms in MDR A. baumannii, we report the first large scale 2D LC/MS/MS-based quantitative proteomics comparison of a drug-sensitive strain and an MDR strain of this pathogen. Ca. 20% of the expressed proteome changes 2-fold or more between the compared strains, including 42 proteins with literature or informatics annotations related to resistance mechanisms, modification of xenobiotics, or drug transport. Other categories of proteins differing 2-fold or more between strains include stress-response related proteins, porins, OMPs, transporters and secretion-related proteins, cell wall- and expolysaccharide-related proteins, lipoproteins, and DNA- and plasmid-related proteins. While the compared strains also differ in other aspects than multi-drug resistance, the observed differences, combined with protein functional annotation, suggest that complex protein expression changes may accompany the MDR phenotype. Expression changes of nine proteins in the MDR strain can potentially account for the observed resistance to 18 antibiotics.
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Affiliation(s)
- Sidharth Chopra
- Center for Infectious Disease and Biodefense Research, SRI International, 333 Ravenswood, Avenue, Menlo Park, CA 94025, USA
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Huang J, Jiang F, Hu Y, Zhou X, Gu S, Jiao XA. An Inactivation Kinetics Model for Campylobacter jejuni on Chicken Meat Under Low-Temperature Storage. Foodborne Pathog Dis 2012; 9:513-6. [DOI: 10.1089/fpd.2011.1070] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Jinlin Huang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, P.R. China
| | - Feng Jiang
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, P.R. China
| | - Yuanqing Hu
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, P.R. China
| | - Xiaohui Zhou
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, P.R. China
| | - Shiliang Gu
- Agricultural College of Yangzhou University, Yangzhou, Jiangsu, P.R. China
| | - Xin-an Jiao
- Jiangsu Key Laboratory of Zoonosis, Yangzhou University, Yangzhou, Jiangsu, P.R. China
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Kassem II, Zhang Q, Rajashekara G. The twin-arginine translocation system: contributions to the pathobiology of Campylobacter jejuni. Future Microbiol 2012; 6:1315-27. [PMID: 22082291 DOI: 10.2217/fmb.11.107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The twin-arginine translocation (Tat) system is specialized in the transport of folded proteins across the cytoplasmic membrane. Although the mechanisms that govern the Tat transport and its scope are not well understood, this system and its cognate substrates are involved in important functions that facilitate the adaptation and survival of bacteria. Evidence also exists that connects the Tat system to virulent traits of clinically relevant pathogens. Of interest is Campylobacter jejuni, an important foodborne pathogen that is capable of surviving in different hosts and environmental niches. Recent studies have shown that the Tat system in this bacterium mediates key metabolic and stress resistance traits. Furthermore, the majority of the identified Tat substrates in C. jejuni are cofactor-containing redox proteins that contribute to the bacterium?s branched electron transport chain, a component essential for survival under differing conditions. These studies as well as the absence of Tat homologs in the sequenced genomes of animals suggest that the Tat system might pose an attractive target for therapeutics against C. jejuni.
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Affiliation(s)
- Issmat I Kassem
- Food Animal Health Research Program, Ohio Agricultural Research & Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, OH 44691, USA
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Kassem II, Rajashekara G. An ancient molecule in a recalcitrant pathogen: the contributions of poly-P to the pathogenesis and stress responses of Campylobacter jejuni. Future Microbiol 2012; 6:1117-20. [PMID: 22004028 DOI: 10.2217/fmb.11.94] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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44
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Drozd M, Gangaiah D, Liu Z, Rajashekara G. Contribution of TAT system translocated PhoX to Campylobacter jejuni phosphate metabolism and resilience to environmental stresses. PLoS One 2011; 6:e26336. [PMID: 22028859 PMCID: PMC3197622 DOI: 10.1371/journal.pone.0026336] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 09/25/2011] [Indexed: 12/12/2022] Open
Abstract
Campylobacter jejuni is a common gastrointestinal pathogen that colonizes food animals; it is transmitted via fecal contamination of food, and infections in immune-compromised people are more likely to result in serious long-term illness. Environmental phosphate is likely an important sensor of environmental fitness and the ability to obtain extracellular phosphate is central to the bacteria's core metabolic responses. PhoX is the sole alkaline phosphatase in C. jejuni, a substrate of the TAT transport system. Alkaline phosphatases mediate the hydrolytic removal of inorganic phosphate (Pi) from phospho-organic compounds and thereby contribute significantly to the polyphosphate kinase 1 (ppk1) mediated formation of poly P, a molecule that regulates bacterial response to stresses and virulence. Similarly, deletion of the tatC gene, a key component of the TAT system, results in diverse phenotypes in C. jejuni including reduced stress tolerance and in vivo colonization. Therefore, here we investigated the contribution of phoX in poly P synthesis and in TAT-system mediated responses. The phoX deletion mutant showed significant decrease (P<0.05) in poly P accumulation in stationary phase compared to the wild-type, suggesting that PhoX is a major contributor to the inorganic phosphate pool in the cell which is essential for poly P synthesis. The phoX deletion is sufficient for a nutrient stress defect similar to the defect previously described for the ΔtatC mutant. Additionally, the phoX deletion mutant has increased resistance to certain antimicrobials. The ΔphoX mutant was also moderately defective in invasion and intracellular survival within human intestinal epithelial cells as well as in chicken colonization. Further, the ΔphoX mutant produced increased biofilm that can be rescued with 1 mM inorganic phosphate. The qRT-PCR of the ΔphoX mutant revealed transcriptional changes that suggest potential mechanisms for the increased biofilm phenotype.
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Affiliation(s)
- Mary Drozd
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, United States of America
| | - Dharanesh Gangaiah
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, United States of America
| | - Zhe Liu
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, United States of America
| | - Gireesh Rajashekara
- Food Animal Health Research Program, Department of Veterinary Preventive Medicine, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, Ohio, United States of America
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Gangaiah D, Liu Z, Arcos J, Kassem II, Sanad Y, Torrelles JB, Rajashekara G. Polyphosphate kinase 2: a novel determinant of stress responses and pathogenesis in Campylobacter jejuni. PLoS One 2010; 5:e12142. [PMID: 20808906 PMCID: PMC2923150 DOI: 10.1371/journal.pone.0012142] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Accepted: 07/21/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND Inorganic polyphosphate (poly P) plays an important role in stress tolerance and virulence in many bacteria. PPK1 is the principal enzyme involved in poly P synthesis, while PPK2 uses poly P to generate GTP, a signaling molecule that serves as an alternative energy source and a precursor for various physiological processes. Campylobacter jejuni, an important cause of foodborne gastroenteritis in humans, possesses homologs of both ppk1 and ppk2. ppk1 has been previously shown to impact the pathobiology of C. jejuni. METHODOLOGY/PRINCIPAL FINDINGS Here, we demonstrate for the first time that the deletion of ppk2 in C. jejuni resulted in a significant decrease in poly P-dependent GTP synthesis, while displaying an increased intracellular ATP:GTP ratio. The Deltappk2 mutant exhibited a significant survival defect under osmotic, nutrient, aerobic, and antimicrobial stresses and displayed an enhanced ability to form static biofilms. However, the Deltappk2 mutant was not defective in poly P and ppGpp synthesis suggesting that PPK2-mediated stress tolerance is not ppGpp-mediated. Importantly, the Deltappk2 mutant was significantly attenuated in invasion and intracellular survival within human intestinal epithelial cells as well as in chicken colonization. CONCLUSIONS/SIGNIFICANCE Taken together, we have highlighted the role of PPK2 as a novel pathogenicity determinant that is critical for C. jejuni survival, adaptation, and persistence in the host environments. PPK2 is absent in humans and animals; therefore, can serve as a novel target for therapeutic intervention of C. jejuni infections.
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Affiliation(s)
- Dharanesh Gangaiah
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio, United States of America
| | - Zhe Liu
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio, United States of America
| | - Jesús Arcos
- Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Issmat I. Kassem
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio, United States of America
| | - Yasser Sanad
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio, United States of America
| | - Jordi B. Torrelles
- Center for Microbial Interface Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Gireesh Rajashekara
- Food Animal Health Research Program, Ohio Agricultural Research Development Center, Department of Veterinary Preventive Medicine, The Ohio State University, Wooster, Ohio, United States of America
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Siddiqui R, Siti AH. Use of reducing agents for the aerobic growth of Campylobacter jejuni. ASIAN PAC J TROP MED 2010. [DOI: 10.1016/s1995-7645(10)60016-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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