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González-López I, Medrano-Félix JA, Castro-Del Campo N, López-Cuevas O, Ibarra Rodríguez JR, Martinez-Rodríguez C, Valdez-Torres JB, Chaidez C. Metabolic plasticity of Salmonella enterica as adaptation strategy in river water. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2022; 32:1529-1541. [PMID: 33706620 DOI: 10.1080/09603123.2021.1896682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 02/24/2021] [Indexed: 06/12/2023]
Abstract
The survival of Salmonella in subtropical river water depends on genetic and metabolic reorganization for the expression of alternative metabolic pathways in response to starvation, which allows Salmonella to use environmental carbon sources (C-sources). However, knowledge regarding the metabolic plasticity of Salmonella serotypes for C-source utilization when exposed to these conditions remains unclear. The aim of this study was to evaluate the metabolic response and level of environmental C-source consumption by environmental Salmonella (Oranienburg and Saintpaul) and clinical Salmonella (Typhi) serotypes by comparing laboratory growth against exposure to river water conditions. Metabolic characterization was performed using a Biolog® EcoPlateTM containing 31 C-sources. The results obtained under laboratory growth conditions showed that environmental serotypes used 74.1% of the C-sources, whereas the clinical serotype used 45.1%. In contrast, in river water, all strains used up to 96.7% of the C-sources. Salmonella exposure to river water increases its capacity to use environmental C-sources.
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Affiliation(s)
- Irvin González-López
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | - José Andrés Medrano-Félix
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, CONACYT-Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | - Nohelia Castro-Del Campo
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | - Osvaldo López-Cuevas
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | | | - Celida Martinez-Rodríguez
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | - José Benigno Valdez-Torres
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
| | - Cristóbal Chaidez
- Environmental Microbiology, Laboratorio Nacional Para La Investigación En Inocuidad Alimentaria, Centro De Investigación En Alimentación Y Desarrollo A.C, Culiacán, Sinaloa, México
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Chaidez C, Peraza-Garay FDJ, Medrano-Félix JA, Castro-Del Campo N, López-Cuevas O. Phenotypic traits of carbon source utilization in environmental Salmonella strains isolated from river water. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2022; 32:1155-1163. [PMID: 33251827 DOI: 10.1080/09603123.2020.1849578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Salmonella in the environment have evolved genetically to maintain a stable cell metabolism. Nevertheless, a lack of common nutrients (such as glucose) causes these strains to metabolize alternative carbon sources. In this study, 21 strains of Salmonella Oranienburg isolated from subtropical river water were evaluated to compare their adaptation and preconditioning abilities for the consumption of environmental carbon sources (ECS). The results obtained in this study attributed important biological characteristics to the adaptation of the metabolism of Salmonella strains to diverse ECS; these characteristics include but are not limited to variations in plasticity and natural preconditioning in closely related microorganisms, such as environmental isolates belonging to the serotype Oranienburg.
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Affiliation(s)
- Cristóbal Chaidez
- The department is Environmental microbiology, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (LANIIA, Centro de Investigación en Alimentación y Desarrollo, A.C. Carretera a Eldorado, Culiacán, México
| | | | | | - Nohelia Castro-Del Campo
- The department is Environmental microbiology, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (LANIIA, Centro de Investigación en Alimentación y Desarrollo, A.C. Carretera a Eldorado, Culiacán, México
| | - Osvaldo López-Cuevas
- The department is Environmental microbiology, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria (LANIIA, Centro de Investigación en Alimentación y Desarrollo, A.C. Carretera a Eldorado, Culiacán, México
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3
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Zulkefli NJ, Teh CSJ, Mariappan V, Ngoi ST, Vadivelu J, Ponnampalavanar S, Chai LC, Chong CW, Yap IKS, Vellasamy KM. Genomic comparison and phenotypic profiling of small colony variants of Burkholderia pseudomallei. PLoS One 2021; 16:e0261382. [PMID: 34910764 PMCID: PMC8673655 DOI: 10.1371/journal.pone.0261382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 11/30/2021] [Indexed: 11/18/2022] Open
Abstract
Burkholderia pseudomallei (B. pseudomallei) is an intracellular pathogen that causes melioidosis, a life-threatening infection in humans. The bacterium is able to form small colony variants (SCVs) as part of the adaptive features in response to environmental stress. In this study, we characterize the genomic characteristics, antimicrobial resistance (AMR), and metabolic phenotypes of B. pseudomallei SCV and wild type (WT) strains. Whole-genome sequence analysis was performed to characterize the genomic features of two SCVs (CS and OS) and their respective parental WT strains (CB and OB). Phylogenetic relationship between the four draft genomes in this study and 19 publicly available genomes from various countries was determined. The four draft genomes showed a close phylogenetic relationship with other genomes from Southeast Asia. Broth microdilution and phenotype microarray were conducted to determine the AMR profiles and metabolic features (carbon utilization, osmolytes sensitivity, and pH conditions) of all strains. The SCV strains exhibited identical AMR phenotype with their parental WT strains. A limited number of AMR-conferring genes were identified in the B. pseudomallei genomes. The SCVs and their respective parental WT strains generally shared similar carbon-utilization profiles, except for D,L-carnitine (CS), g-hydroxybutyric acid (OS), and succinamic acid (OS) which were utilized by the SCVs only. No difference was observed in the osmolytes sensitivity of all strains. In comparison, WT strains were more resistant to alkaline condition, while SCVs showed variable growth responses at higher acidity. Overall, the genomes of the colony morphology variants of B. pseudomallei were largely identical, and the phenotypic variations observed among the different morphotypes were strain-specific.
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Affiliation(s)
- Noorfatin Jihan Zulkefli
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cindy Shuan Ju Teh
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
- * E-mail: (CSJT); (KMV)
| | - Vanitha Mariappan
- Faculty of Health Sciences, Centre of Toxicology and Health Risk Studies (CORE), Universiti Kebangsaan Malaysia, Kuala Lumpur, Malaysia
| | - Soo Tein Ngoi
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Jamuna Vadivelu
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
| | | | - Lay Ching Chai
- Faculty of Science, Institute of Biological Sciences, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Chun Wie Chong
- School of Pharmacy, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia
- Institute for Research, Development & Innovation, International Medical University, Kuala Lumpur, Malaysia
| | - Ivan Kok Seng Yap
- Sarawak Research and Development Council, Kuching, Sarawak, Malaysia
| | - Kumutha Malar Vellasamy
- Faculty of Medicine, Department of Medical Microbiology, Universiti Malaya, Kuala Lumpur, Malaysia
- * E-mail: (CSJT); (KMV)
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Seif Y, Kavvas E, Lachance JC, Yurkovich JT, Nuccio SP, Fang X, Catoiu E, Raffatellu M, Palsson BO, Monk JM. Genome-scale metabolic reconstructions of multiple Salmonella strains reveal serovar-specific metabolic traits. Nat Commun 2018; 9:3771. [PMID: 30218022 PMCID: PMC6138749 DOI: 10.1038/s41467-018-06112-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 08/17/2018] [Indexed: 01/08/2023] Open
Abstract
Salmonella strains are traditionally classified into serovars based on their surface antigens. While increasing availability of whole-genome sequences has allowed for more detailed subtyping of strains, links between genotype, serovar, and host remain elusive. Here we reconstruct genome-scale metabolic models for 410 Salmonella strains spanning 64 serovars. Model-predicted growth capabilities in over 530 different environments demonstrate that: (1) the Salmonella accessory metabolic network includes alternative carbon metabolism, and cell wall biosynthesis; (2) metabolic capabilities correspond to each strain's serovar and isolation host; (3) growth predictions agree with 83.1% of experimental outcomes for 12 strains (690 out of 858); (4) 27 strains are auxotrophic for at least one compound, including L-tryptophan, niacin, L-histidine, L-cysteine, and p-aminobenzoate; and (5) the catabolic pathways that are important for fitness in the gastrointestinal environment are lost amongst extraintestinal serovars. Our results reveal growth differences that may reflect adaptation to particular colonization sites.
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Affiliation(s)
- Yara Seif
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Erol Kavvas
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | | | - James T Yurkovich
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
- Bioinformatics and Systems Biology Program, University of California, San Diego, La Jolla, USA
| | - Sean-Paul Nuccio
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Xin Fang
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Edward Catoiu
- Department of Bioengineering, University of California, San Diego, La Jolla, USA
| | - Manuela Raffatellu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Bernhard O Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, USA.
- Bioinformatics and Systems Biology Program, University of California, San Diego, La Jolla, USA.
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA.
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800, Kongens, Lyngby, Denmark.
| | - Jonathan M Monk
- Department of Bioengineering, University of California, San Diego, La Jolla, USA.
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Medrano-Félix A, Estrada-Acosta M, Peraza-Garay F, Castro-Del Campo N, Martínez-Urtaza J, Chaidez C. Differences in carbon source utilization of Salmonella Oranienburg and Saintpaul isolated from river water. INTERNATIONAL JOURNAL OF ENVIRONMENTAL HEALTH RESEARCH 2017; 27:252-263. [PMID: 28565917 DOI: 10.1080/09603123.2017.1332349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Accepted: 05/15/2017] [Indexed: 06/07/2023]
Abstract
Long-term exposure to river water by non-indigenous micro-organisms such as Salmonella may affect metabolic adaptation to carbon sources. This study was conducted to determine differences in carbon source utilization of Salmonella Oranienburg and Salmonella Saintpaul (isolated from tropical river water) as well as the control strain Salmonella Typhimurium exposed to laboratory, river water, and host cells (Hep-2 cell line) growth conditions. Results showed that Salmonella Oranienburg and Salmonella Saintpaul showed better ability for carbon source utilization under the three growth conditions evaluated; however, S. Oranienburg showed the fastest and highest utilization on different carbon sources, including D-Glucosaminic acid, N-acetyl-D-Glucosamine, Glucose-1-phosphate, and D-Galactonic acid, while Salmonella Saintpaul and S. Typhimurium showed a limited utilization of carbon sources. In conclusion, this study suggests that environmental Salmonella strains show better survival and preconditioning abilities to external environments than the control strain based on their plasticity on diverse carbon sources use.
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Affiliation(s)
- Andrés Medrano-Félix
- a CONACYT-Centro de Investigación en Alimentación y Desarrollo A.C. , Coordinación Regional Culiacán, Laboratorio Nacional para la Investigación en Inocuidad Alimentaria. Culiacán , Sinaloa , México
| | | | - Felipe Peraza-Garay
- c Centro de Investigación y Docencia en Ciencias de la Salud , Universidad Autónoma de Sinaloa , Sinaloa , México
| | - Nohelia Castro-Del Campo
- d Centro de Investigación en Alimentación y Desarrollo A.C. , Coordinación Regional Culiacán Laboratorio Nacional para la Investigación en Inocuidad Alimentaria. Culiacán , Sinaloa , México
| | | | - Cristóbal Chaidez
- d Centro de Investigación en Alimentación y Desarrollo A.C. , Coordinación Regional Culiacán Laboratorio Nacional para la Investigación en Inocuidad Alimentaria. Culiacán , Sinaloa , México
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Lactate oxidation facilitates growth of Mycobacterium tuberculosis in human macrophages. Sci Rep 2017; 7:6484. [PMID: 28744015 PMCID: PMC5526930 DOI: 10.1038/s41598-017-05916-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 06/06/2017] [Indexed: 11/09/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) uses alveolar macrophages as primary host cells during infection. In response to an infection, macrophages switch from pyruvate oxidation to reduction of pyruvate into lactate. Lactate might present an additional carbon substrate for Mtb. Here, we demonstrate that Mtb can utilize L-lactate as sole carbon source for in vitro growth. Lactate conversion is strictly dependent on one of two potential L-lactate dehydrogenases. A knock-out mutant lacking lldD2 (Rv1872c) was unable to utilize L-lactate. In contrast, the lldD1 (Rv0694) knock-out strain was not affected in growth on lactate and retained full enzymatic activity. On the basis of labelling experiments using [U-13C3]-L-lactate as a tracer the efficient uptake of lactate by Mtb and its conversion into pyruvate could be demonstrated. Moreover, carbon flux from lactate into the TCA cycle, and through gluconeogenesis was observed. Gluconeogenesis during lactate consumption depended on the phosphoenolpyruvate carboxykinase, a key enzyme for intracellular survival, showing that lactate utilization requires essential metabolic pathways. We observed that the ΔlldD2 mutant was impaired in replication in human macrophages, indicating a critical role for lactate oxidation during intracellular growth.
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Yap KP, Thong KL. Salmonella Typhi genomics: envisaging the future of typhoid eradication. Trop Med Int Health 2017; 22:918-925. [PMID: 28544285 DOI: 10.1111/tmi.12899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Next-generation whole-genome sequencing has revolutionised the study of infectious diseases in recent years. The availability of genome sequences and its understanding have transformed the field of molecular microbiology, epidemiology, infection treatments and vaccine developments. We review the key findings of the publicly accessible genomes of Salmonella enterica serovar Typhi since the first complete genome to the most recent release of thousands of Salmonella Typhi genomes, which remarkably shape the genomic research of S. Typhi and other pathogens. Important new insights acquired from the genome sequencing of S. Typhi, pertaining to genomic variations, evolution, population structure, antibiotic resistance, virulence, pathogenesis, disease surveillance/investigation and disease control are discussed. As the numbers of sequenced genomes are increasing at an unprecedented rate, fine variations in the gene pool of S. Typhi are captured in high resolution, allowing deeper understanding of the pathogen's evolutionary trends and its pathogenesis, paving the way to bringing us closer to eradication of typhoid through effective vaccine/treatment development.
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Affiliation(s)
- Kien-Pong Yap
- Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Institute of Biological Science, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
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Singh V, Finke-Isami J, Hopper-Chidlaw AC, Schwerk P, Thompson A, Tedin K. Salmonella Co-opts Host Cell Chaperone-mediated Autophagy for Intracellular Growth. J Biol Chem 2017; 292:1847-1864. [PMID: 27932462 PMCID: PMC5290957 DOI: 10.1074/jbc.m116.759456] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/01/2016] [Indexed: 01/05/2023] Open
Abstract
Salmonella enterica are invasive intracellular pathogens that replicate within a membrane-bound compartment inside infected host cells known as the Salmonella-containing vacuole. How Salmonella obtains nutrients for growth within this intracellular niche despite the apparent isolation is currently not known. Recent studies have indicated the importance of glucose and related carbon sources for tissue colonization and intracellular proliferation within host cells during Salmonella infections, although none have been found to be essential. We found that wild-type Salmonella are capable of replicating within infected host cells in the absence of both exogenous sugars and/or amino acids. Furthermore, mutants defective in glucose uptake or dependent upon peptides for growth also showed no significant loss in intracellular replication, suggesting host-derived peptides can supply both carbon units and amino acids. Here, we show that intracellular Salmonella recruit the host proteins LAMP-2A and Hsc73, key components of the host protein turnover pathway known as chaperone-mediated autophagy involved in transport of cytosolic proteins to the lysosome for degradation. Host-derived peptides are shown to provide a significant contribution toward the intracellular growth of Salmonella The results reveal a means whereby intracellular Salmonella gain access to the host cell cytosol from within its membrane-bound compartment to acquire nutrients. Furthermore, this study provides an explanation as to how Salmonella evades activation of autophagy mechanisms as part of the innate immune response.
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Affiliation(s)
- Vikash Singh
- From the Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany
| | - Johannes Finke-Isami
- From the Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany
| | | | - Peter Schwerk
- From the Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany
| | - Arthur Thompson
- the Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, United Kingdom
| | - Karsten Tedin
- From the Centre for Infection Medicine, Institute of Microbiology and Epizootics, Freie Universität Berlin, 14163 Berlin, Germany.
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Kalai Chelvam K, Yap KP, Chai LC, Thong KL. Variable Responses to Carbon Utilization between Planktonic and Biofilm Cells of a Human Carrier Strain of Salmonella enterica Serovar Typhi. PLoS One 2015; 10:e0126207. [PMID: 25946205 PMCID: PMC4422432 DOI: 10.1371/journal.pone.0126207] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Accepted: 03/31/2015] [Indexed: 12/29/2022] Open
Abstract
Salmonella enterica serovar Typhi (S. Typhi) is a foodborne pathogen that causes typhoid fever and infects only humans. The ability of S. Typhi to survive outside the human host remains unclear, particularly in human carrier strains. In this study, we have investigated the catabolic activity of a human carrier S. Typhi strain in both planktonic and biofilm cells using the high-throughput Biolog Phenotype MicroArray, Minimum Biofilm Eradication Concentration (MBEC) biofilm inoculator (96-well peg lid) and whole genome sequence data. Additional strains of S. Typhi were tested to further validate the variation of catabolism in selected carbon substrates in the different bacterial growth phases. The analyzes of the carbon utilization data indicated that planktonic cells of the carrier strain, S. Typhi CR0044 could utilize a broader range of carbon substrates compared to biofilm cells. Pyruvic acid and succinic acid which are related to energy metabolism were actively catabolised in the planktonic stage compared to biofilm stage. On the other hand, glycerol, L-fucose, L-rhamnose (carbohydrates) and D-threonine (amino acid) were more actively catabolised by biofilm cells compared to planktonic cells. Notably, dextrin and pectin could induce strong biofilm formation in the human carrier strain of S. Typhi. However, pectin could not induce formation of biofilm in the other S. Typhi strains. Phenome data showed the utilization of certain carbon substrates which was supported by the presence of the catabolism-associated genes in S. Typhi CR0044. In conclusion, the findings showed the differential carbon utilization between planktonic and biofilm cells of a S. Typhi human carrier strain. The differences found in the carbon utilization profiles suggested that S. Typhi uses substrates mainly found in the human biliary mucus glycoprotein, gallbladder, liver and cortex of the kidney of the human host. The observed diversity in the carbon catabolism profiles among different S. Typhi strains has suggested the possible involvement of various metabolic pathways that might be related to the virulence and pathogenesis of this host-restricted human pathogen. The data serve as a caveat for future in-vivo studies to investigate the carbon metabolic activity to the pathogenesis of S. Typhi.
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Affiliation(s)
- Kalaivani Kalai Chelvam
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kien Pong Yap
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Lay Ching Chai
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
| | - Kwai Lin Thong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
- * E-mail:
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Kalai Chelvam K, Chai LC, Thong KL. Variations in motility and biofilm formation of Salmonella enterica serovar Typhi. Gut Pathog 2014; 6:2. [PMID: 24499680 PMCID: PMC3922113 DOI: 10.1186/1757-4749-6-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Accepted: 01/28/2014] [Indexed: 01/02/2023] Open
Abstract
Background Salmonella enterica serovar Typhi (S. Typhi) exhibits unique characteristics as an intracellular human pathogen. It causes both acute and chronic infection with various disease manifestations in the human host only. The principal factors underlying the unique lifestyle of motility and biofilm forming ability of S. Typhi remain largely unknown. The main objective of this study was to explore and investigate the motility and biofilm forming behaviour among S. Typhi strains of diverse background. Results Swim and swarm motility tests were performed with 0.25% and 0.5% agar concentration, respectively; while biofilm formation was determined by growing the bacterial cultures for 48 hrs in 96-well microtitre plate. While all S. Typhi strains demonstrated swarming motility with smooth featureless morphology, 58 out of 60 strains demonstrated swimming motility with featureless or bull’s eye morphology. Interestingly, S. Typhi strains of blood-borne origin exhibited significantly higher swimming motility (P < 0.05) than stool-borne strains suggesting that swimming motility may play a role in the systemic invasion of S. Typhi in the human host. Also, stool-borne S. Typhi displayed a negative relationship between motility and biofilm forming behaviour, which was not observed in the blood-borne strains. Conclusion In summary, both swimming and swarming motility are conserved among S. Typhi strains but there was variation for biofilm forming ability. There was no difference observed in this phenotype for S. Typhi strains from diverse background. These findings serve as caveats for future studies to understand the lifestyle and transmission of this pathogen.
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Affiliation(s)
| | | | - Kwai Lin Thong
- Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
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The genome of Pseudomonas fluorescens strain R124 demonstrates phenotypic adaptation to the mineral environment. J Bacteriol 2013; 195:4793-803. [PMID: 23995634 DOI: 10.1128/jb.00825-13] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microbial adaptation to environmental conditions is a complex process, including acquisition of positive traits through horizontal gene transfer or the modification of existing genes through duplication and/or mutation. In this study, we examined the adaptation of a Pseudomonas fluorescens isolate (R124) from the nutrient-limited mineral environment of a silica cave in comparison with P. fluorescens isolates from surface soil and the rhizosphere. Examination of metal homeostasis gene pathways demonstrated a high degree of conservation, suggesting that such systems remain functionally similar across chemical environments. The examination of genomic islands unique to our strain revealed the presence of genes involved in carbohydrate metabolism, aromatic carbon metabolism, and carbon turnover, confirmed through phenotypic assays, suggesting the acquisition of potentially novel mechanisms for energy metabolism in this strain. We also identified a twitching motility phenotype active at low-nutrient concentrations that may allow alternative exploratory mechanisms for this organism in a geochemical environment. Two sets of candidate twitching motility genes are present within the genome, one on the chromosome and one on a plasmid; however, a plasmid knockout identified the functional gene as being present on the chromosome. This work highlights the plasticity of the Pseudomonas genome, allowing the acquisition of novel nutrient-scavenging pathways across diverse geochemical environments while maintaining a core of functional stress response genes.
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Comparative Virulotyping of Salmonella typhi and Salmonella enteritidis. Indian J Microbiol 2013; 53:410-7. [PMID: 24426144 DOI: 10.1007/s12088-013-0407-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 04/12/2013] [Indexed: 10/26/2022] Open
Abstract
Members of Salmonella enterica are important foodborne pathogens of significant public health concern worldwide. This study aimed to determine a range of virulence genes among typhoidal (S. typhi) and non-typhoidal (S. enteritidis) strains isolated from different geographical regions and different years. A total of 87 S. typhi and 94 S. enteritidis strains were tested for presence of 22 virulence genes by employing multiplex PCR and the genetic relatedness of these strains was further characterized by REP-PCR. In S. typhi, invA, prgH, sifA, spiC, sopB, iroN, sitC, misL, pipD, cdtB, and orfL were present in all the strains, while sopE, agfC, agfA, sefC, mgtC, and sefD were present in 98.8, 97.7, 90.8, 87.4, 87.4 and 17.2 %, of the strains, respectively. No lpfA, lpfC, pefA, spvB, or spvC was detected. Meanwhile, in S. enteritidis, 15 genes, agfA, agfC, invA, lpfA, lpfC, sefD, prgH, spiC, sopB, sopE, iroN, sitC, misL, pipD, and orfL were found in all S. enteritidis strains 100 %, followed by sifA and spvC 98.9 %, pefA, spvB and mgtC 97.8 %, and sefC 90.4 %. cdtB was absent from all S. enteritidis strains tested. REP-PCR subtyped S. typhi strains into 18 REP-types and concurred with the virulotyping results in grouping the strains, while in S. enteritidis, REP-PCR subtyped the strains into eight profiles and they were poorly distinguishable between human and animal origins. The study showed that S. typhi and S. enteritidis contain a range of virulence factors associated with pathogenesis. Virulotyping is a rapid screening method to identify and profile virulence genes in Salmonella strains, and improve an understanding of potential risk for human and animal infections.
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