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Hitomi K, Ishii Y, Ying BW. Experimental evolution for the recovery of growth loss due to genome reduction. eLife 2024; 13:RP93520. [PMID: 38690805 PMCID: PMC11062635 DOI: 10.7554/elife.93520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2024] Open
Abstract
As the genome encodes the information crucial for cell growth, a sizeable genomic deficiency often causes a significant decrease in growth fitness. Whether and how the decreased growth fitness caused by genome reduction could be compensated by evolution was investigated here. Experimental evolution with an Escherichia coli strain carrying a reduced genome was conducted in multiple lineages for approximately 1000 generations. The growth rate, which largely declined due to genome reduction, was considerably recovered, associated with the improved carrying capacity. Genome mutations accumulated during evolution were significantly varied across the evolutionary lineages and were randomly localized on the reduced genome. Transcriptome reorganization showed a common evolutionary direction and conserved the chromosomal periodicity, regardless of highly diversified gene categories, regulons, and pathways enriched in the differentially expressed genes. Genome mutations and transcriptome reorganization caused by evolution, which were found to be dissimilar to those caused by genome reduction, must have followed divergent mechanisms in individual evolutionary lineages. Gene network reconstruction successfully identified three gene modules functionally differentiated, which were responsible for the evolutionary changes of the reduced genome in growth fitness, genome mutation, and gene expression, respectively. The diversity in evolutionary approaches improved the growth fitness associated with the homeostatic transcriptome architecture as if the evolutionary compensation for genome reduction was like all roads leading to Rome.
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Affiliation(s)
- Kenya Hitomi
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
| | - Yoichiro Ishii
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
| | - Bei-Wen Ying
- School of Life and Environmental Sciences, University of TsukubaTsukubaJapan
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2
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Yang X, Narvaez-Bravo C, Zhang P. Driving forces shaping the microbial ecology in meat packing plants. Front Microbiol 2024; 14:1333696. [PMID: 38322759 PMCID: PMC10844536 DOI: 10.3389/fmicb.2023.1333696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Accepted: 12/22/2023] [Indexed: 02/08/2024] Open
Abstract
Meat production is a complex system, continually receiving animals, water, air, and workers, all of which serve as carriers of bacteria. Selective pressures involved in different meat processing stages such as antimicrobial interventions and low temperatures, may promote the accumulation of certain residential microbiota in meat cutting facilities. Bacteria including human pathogens from all these sources can contaminate meat surfaces. While significant advancements have been made in enhancing hygienic standards and pathogen control measures in meat plants, resulting in a notable reduction in STEC recalls and clinical cases, STEC still stands as a predominant contributor to foodborne illnesses associated with beef and occasionally with pork. The second-and third-generation sequencing technology has become popular in microbiota related studies and provided a better image of the microbial community in the meat processing environments. In this article, we reviewed the potential factors influencing the microbial ecology in commercial meat processing facilities and conducted a meta-analysis on the microbiota data published in the last 10 years. In addition, the mechanisms by which bacteria persist in meat production environments have been discussed with a focus on the significant human pathogen E. coli O157:H7 and generic E. coli, an indicator often used for the hygienic condition in food production.
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Affiliation(s)
- Xianqin Yang
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, Canada
| | | | - Peipei Zhang
- Lacombe Research and Development Centre, Agriculture and Agri-Food Canada, Lacombe, AB, Canada
- Department of Animal Sciences, Center for Meat Safety and Quality, Colorado State University, Fort Collins, CO, United States
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3
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Rihacek M, Kosaristanova L, Fialova T, Kuthanova M, Eichmeier A, Hakalova E, Cerny M, Berka M, Palkovicova J, Dolejska M, Svec P, Adam V, Zurek L, Cihalova K. Zinc effects on bacteria: insights from Escherichia coli by multi-omics approach. mSystems 2023; 8:e0073323. [PMID: 37905937 PMCID: PMC10734530 DOI: 10.1128/msystems.00733-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 09/25/2023] [Indexed: 11/02/2023] Open
Abstract
IMPORTANCE A long-term exposure of bacteria to zinc oxide and zinc oxide nanoparticles leads to major alterations in bacterial morphology and physiology. These included biochemical and physiological processes promoting the emergence of strains with multi-drug resistance and virulence traits. After the removal of zinc pressure, bacterial phenotype reversed back to the original state; however, certain changes at the genomic, transcriptomic, and proteomic level remained. Why is this important? The extensive and intensive use of supplements in animal feed effects the intestinal microbiota of livestock and this may negatively impact the health of animals and people. Therefore, it is crucial to understand and monitor the impact of feed supplements on intestinal microorganisms in order to adequately assess and prevent potential health risks.
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Affiliation(s)
- Martin Rihacek
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Ludmila Kosaristanova
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Tatiana Fialova
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Michaela Kuthanova
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Ales Eichmeier
- Faculty of Horticulture, Mendeleum—Institute of Genetics, Mendel University in Brno, Brno, Czechia
| | - Eliska Hakalova
- Faculty of Horticulture, Mendeleum—Institute of Genetics, Mendel University in Brno, Brno, Czechia
| | - Martin Cerny
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences Mendel University in Brno, Brno, Czechia
| | - Miroslav Berka
- Department of Molecular Biology and Radiobiology, Faculty of AgriSciences Mendel University in Brno, Brno, Czechia
| | - Jana Palkovicova
- Faculty of Medicine in Pilsen, Biomedical Center, Charles University, Pilsen, Czechia
- Central European Institute of Technology, University of Veterinary Sciences Brno, Brno, Czechia
| | - Monika Dolejska
- Faculty of Medicine in Pilsen, Biomedical Center, Charles University, Pilsen, Czechia
- Central European Institute of Technology, University of Veterinary Sciences Brno, Brno, Czechia
- Department of Biology and Wildlife Diseases, Faculty of Veterinary Hygiene and Ecology, University of Veterinary Sciences Brno, Brno, Czechia
- Department of Clinical Microbiology and Immunology, Institute of Laboratory Medicine, The University Hospital Brno, Brno, Czechia
| | - Pavel Svec
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Vojtech Adam
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Ludek Zurek
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
| | - Kristyna Cihalova
- Department of Chemistry and Biochemistry, Faculty of AgriSciences, Mendel University in Brno, Brno, Czechia
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Zhang S, Su J, Liu S, Ren Y, Cao S. Regulating mechanism of denitrifier Comamonas sp. YSF15 in response to carbon deficiency: Based on carbon/nitrogen functions and bioaggregation. ENVIRONMENTAL RESEARCH 2023; 235:116661. [PMID: 37451570 DOI: 10.1016/j.envres.2023.116661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/04/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
There is an urgent demand to investigate mechanisms for the improvement of denitrification in carbon-deficient environment, which will effectively reduce the eutrophication in water bodies polluted by nitrate. In this study, denitrifying bacterium Comamonas sp. YSF15 was used to explore the differences in different carbon source concentrations, with the complete genome, metabolomics, and other detecting methods. Results showed that strain YSF15 was able to achieve efficient denitrification, with complete pathways for denitrification and central carbon metabolism. The carbon deficiency prompted the bacteria to use extracellular amino acid-like metabolites initially, to alleviate inhibition and maintain bioactivity, which also facilitated glycogen storage. The biogenic inhibitors (tautomycin, navitoclax, and glufosinate) at extremely low level potentially favored the competitiveness and intraspecific utilization of extracellular polysaccharides (PS). Optimal solutions for bioaggregation in carbon-deficient condition are achieved by regulating the hydrophobicity, and hydrogen bond in extracellular metabolites. The strategy contributes to the maintenance of bioactivity and adaptation to carbon deficiency. Overall, this study provides a new perspective on understanding the denitrification strategies in carbon-deficient environment, and helps to improve the nitrate removal in low-carbon wastewater treatment.
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Affiliation(s)
- Shuai Zhang
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Junfeng Su
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | - Shuyu Liu
- School of Environment and Chemistry Engineering, Shanghai University, Shanghai, 200444, China.
| | - Yi Ren
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
| | - Shumiao Cao
- School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, 710055, China
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Yang X, Tran F, Zhang P. Comparative Genomic Analyses of Escherichia coli from a Meat Processing Environment in Relation to Their Biofilm Formation and Persistence. Microbiol Spectr 2023; 11:e0018323. [PMID: 37184412 PMCID: PMC10269509 DOI: 10.1128/spectrum.00183-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 04/18/2023] [Indexed: 05/16/2023] Open
Abstract
We investigated the phylogeny of biofilm forming (BF) and nonbiofilm forming (NBF) Escherichia coli (n = 114) from a beef processing environment as well as genetic elements in their BF and persistence via a comparative genomic analysis. Phylogroup B1 made up the largest proportion of both the BF (73.8%) and NBF (50.9%) groups. E. coli from all of the sources that were examined had mixed phylogroups, except for those that were recovered from equipment after cleaning, which were exclusively from phylogroup B1. Both the core genome and gene content trees showed a tree-wide spread of BF strains, with clusters, including both BF and NBF strains. Genome-wide association studies (GWAS) via Scoary or Pyseer did not find any genes or mutations that were overrepresented in the BF group. A retrospective analysis of phenotypes found a significant correlation (P < 0.05) between BF ability and curli production, cellulose synthesis, and/or mobility. However, the BF group also included strains that were negative for curli and cellulose and/or missing encoding genes for the two traits. All curli and cellulose encoding genes were present in most genomes, regardless of their BF status. The degree of motility was correlated with both curli and cellulose production, and 80 common genes were overrepresented in all three of the trait-positive groups. A PTS enzyme II, a subsidiary gluconate catabolism pathway, and an iron-dicitrate transport system were more abundant in the persisting E. coli group. These findings suggest gene function redundancy in E. coli for biofilm formation as well as additional substrate utilization and iron acquisition in its persistence. IMPORTANCE The persistence of potentially hazardous bacteria is a major challenge for meat processing environments, which are conducive for biofilm formation. Marker genes/phenotypes are commonly used to differentiate biofilm forming E. coli strains from their nonbiofilm forming counterparts. We took a comparative genomic analysis approach to analyze E. coli strains that were from the same environment but were differentiated by their biofilm forming ability. A diversification of the genes involved in the biofilm formation of E. coli was observed. Even though there is a correlation on the population level between biofilm formation and the expression of curli and cellulose, uncertainties exist on the individual strain level. Novel substrate utilization and iron acquisition could contribute to the persistence of E. coli. These findings not only advance our understanding of the ecology of E. coli with respect to its persistence but also show that a marker gene/phenotype driven approach for the biofilm control of E. coli may not be prudent.
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Affiliation(s)
- Xianqin Yang
- Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada
| | - Frances Tran
- Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada
| | - Peipei Zhang
- Agriculture and Agri-Food Canada, Lacombe, Alberta, Canada
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6
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Migration Rates on Swim Plates Vary between Escherichia coli Soil Isolates: Differences Are Associated with Variants in Metabolic Genes. Appl Environ Microbiol 2023; 89:e0172722. [PMID: 36695629 PMCID: PMC9972950 DOI: 10.1128/aem.01727-22] [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: 01/26/2023] Open
Abstract
This study investigates migration phenotypes of 265 Escherichia coli soil isolates from the Buffalo River basin in Minnesota, USA. Migration rates on semisolid tryptone swim plates ranged from nonmotile to 190% of the migration rate of a highly motile E. coli K-12 strain. The nonmotile isolate, LGE0550, had mutations in flagellar and chemotaxis genes, including two IS3 elements in the flagellin-encoding gene fliC. A genome-wide association study (GWAS), associating the migration rates with genetic variants in specific genes, yielded two metabolic variants (rygD-serA and metR-metE) with previous implications in chemotaxis. As a novel way of confirming GWAS results, we used minimal medium swim plates to confirm the associations. Other variants in metabolic genes and genes that are associated with biofilm were positively or negatively associated with migration rates. A determination of growth phenotypes on Biolog EcoPlates yielded differential growth for the 10 tested isolates on d-malic acid, putrescine, and d-xylose, all of which are important in the soil environment. IMPORTANCE E. coli is a Gram-negative, facultative anaerobic bacterium whose life cycle includes extra host environments in addition to human, animal, and plant hosts. The bacterium has the genomic capability of being motile. In this context, the significance of this study is severalfold: (i) the great diversity of migration phenotypes that we observed within our isolate collection supports previous (G. NandaKafle, A. A. Christie, S. Vilain, and V. S. Brözel, Front Microbiol 9:762, 2018, https://doi.org/10.3389/fmicb.2018.00762; Y. Somorin, F. Abram, F. Brennan, and C. O'Byrne, Appl Environ Microbiol 82:4628-4640, 2016, https://doi.org/10.1128/AEM.01175-16) ideas of soil promoting phenotypic heterogeneity, (ii) such heterogeneity may facilitate bacterial growth in the many different soil niches, and (iii) such heterogeneity may enable the bacteria to interact with human, animal, and plant hosts.
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Bacterial Siderophores: Structure, Functions, and Role in the Pathogenesis of Infections. PROBLEMS OF PARTICULARLY DANGEROUS INFECTIONS 2022. [DOI: 10.21055/0370-1069-2022-3-14-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This review systematizes and analyzes the data published over the past decade, devoted to the study of low-molecular-weight high affinity iron chelators – siderophores. Siderophores, which are found in bacteria, fungi and mammals, are able to extract iron from insoluble inorganic compounds, and in the host organism – from complexes with proteins that perform the function of nonspecific protection of mammals from infections. The extracted iron is delivered to cells through surface protein receptors specific for each siderophore, as well as various protein transport systems that make up membranes. Siderophores play an important role in virulence in pathogenic bacteria, performing many functions in the host organism, in addition to providing microbes with iron and other biological metals. They participate in the storage of excess iron, toxic to cells, protect bacteria from reactive oxygen compounds, compete for iron with phagocytes, and have a harmful effect on host cells, acting as secreted bacterial toxin in some cases. Bacterial siderophores perform a signaling function and regulate both, their own synthesis and the synthesis of other virulence factors. Many pathogenic bacteria produce several siderophores that are active under different conditions, against various sources of iron in the host organism and at different stages of infectious process. The review presents the results of the experimental studies aimed at elucidating the structure and diverse functions of bacterial siderophores, the mechanisms of their biosynthesis and regulation of expression, as well as the role of these molecules in the physiology and virulence of pathogenic bacteria. Special emphasis is put on siderophores of bacteria causing particularly dangerous infections.
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8
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Liu S, Chen L, Wang L, Zhou B, Ye D, Zheng X, Lin Y, Zeng W, Zhou T, Ye J. Cluster Differences in Antibiotic Resistance, Biofilm Formation, Mobility, and Virulence of Clinical Enterobacter cloacae Complex. Front Microbiol 2022; 13:814831. [PMID: 35464993 PMCID: PMC9019753 DOI: 10.3389/fmicb.2022.814831] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Accepted: 02/24/2022] [Indexed: 12/03/2022] Open
Abstract
Due to the lack of research on the characteristics of different clusters of Enterobacter cloacae complex (ECC), this study aimed to characterize and explore the differences among species of the ECC. An analysis based on hsp60 showed that Enterobacter hormaechei was predominant in ECC. Interestingly, the antibiotic resistance rates of clusters were different, among which E. hormaechei subsp. steigerwaltii (cluster VIII) and Enterobacter cloacae IX (cluster IX) possessed high resistant rates to ciprofloxacin and levofloxacin, but cluster II (Enterobacter kobei) had low resistant rates. Cluster II exhibited a strong biofilm formation ability. Different motility and protease production ability were shown for distinct clusters. A PCR analysis showed that clusters I, III, VI, VIII, and IX carried more virulence genes, while cluster II had fewer. Clusters I, VIII, and IX with high pathogenicity were evaluated using the Galleria mellonella infection model. Thus, the characteristics of resistance, biofilm-forming ability, mobility, and virulence differed among the clusters. The strains were divided into 12 subgroups based on hsp60. The main clusters of ECC clinical strains were I, II, III, VI, VIII, and IX, among which IX, VIII, and I were predominant with high resistance and pathogenicity, and cluster II (E. kobei) was a special taxon with a strong biofilm formation ability under nutrient deficiency, but was associated with low resistance, virulence, and pathogenicity. Hence, clinical classification methods to identify ECC subgroups are an urgent requirement to guide the treatment of clinical infections.
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Affiliation(s)
- Shixing Liu
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Liqiong Chen
- School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, China
| | - Lingbo Wang
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Beibei Zhou
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Dandan Ye
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xiangkuo Zheng
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Yishuai Lin
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Weiliang Zeng
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Tieli Zhou
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jianzhong Ye
- Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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Ballén V, Gabasa Y, Ratia C, Sánchez M, Soto S. Correlation Between Antimicrobial Resistance, Virulence Determinants and Biofilm Formation Ability Among Extraintestinal Pathogenic Escherichia coli Strains Isolated in Catalonia, Spain. Front Microbiol 2022; 12:803862. [PMID: 35087504 PMCID: PMC8786794 DOI: 10.3389/fmicb.2021.803862] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 12/09/2021] [Indexed: 01/29/2023] Open
Abstract
Escherichia coli is a well-characterized bacterium highly prevalent in the human intestinal tract and the cause of many important infections. The aim of this study was to characterize 376 extraintestinal pathogenic E. coli strains collected from four hospitals in Catalonia (Spain) between 2016 and 2017 in terms of antimicrobial resistance, siderophore production, phylogroup classification, and the presence of selected virulence and antimicrobial resistance genes. In addition, the association between these characteristics and the ability to form biofilms was also analyzed. The strains studied were classified into four groups according to their biofilm formation ability: non-biofilm formers (15.7%), weak (23.1%), moderate (35.6%), and strong biofilm formers (25.6%). The strains were highly resistant to ciprofloxacin (48.7%), trimethoprim-sulfamethoxazole (47.9%), and ampicillin (38%), showing a correlation between higher resistance to ciprofloxacin and lower biofilm production. Seventy-three strains (19.4%) were ESBL-producers. However, no relationship between the presence of ESBL and biofilm formation was found. The virulence factor genes fimH (92%), pgaA (84.6%), and irp1 (77.1%) were the most prevalent in all the studied strains. A statistically significant correlation was found between biofilm formation and the presence of iroN, papA, fimH, sfa, cnf, hlyA, iutA, and colibactin-encoding genes clbA, clbB, clbN, and clbQ. Interestingly, a high prevalence of colibactin-encoding genes (19.9%) was observed. Colibactin is a virulence factor, which interferes with the eukaryotic cell cycle and has been associated with colorectal cancer in humans. Most colibactin-encoding E. coli isolates belonged to phylogroup B2, exhibited low antimicrobial resistance but moderate or high biofilm-forming ability, and were significantly associated with most of the virulence factor genes tested. Additionally, the analysis of their clonal relatedness by PFGE showed 48 different clusters, indicating a high clonal diversity among the colibactin-positive strains. Several studies have correlated the pathogenicity of E. coli and the presence of virulence factor genes; however, colibactin and its relationship to biofilm formation have been scarcely investigated. The increasing prevalence of colibactin in E. coli and other Enterobacteriaceae and the recently described correlation with biofilm formation, makes colibactin a promising therapeutic target to prevent biofilm formation and its associated adverse effects.
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Affiliation(s)
- Victoria Ballén
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Yaiza Gabasa
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Carlos Ratia
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Melany Sánchez
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Sara Soto
- ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
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Fatima S, Liaqat F, Akbar A, Sahfee M, Samad A, Anwar M, Iqbal S, Khan SA, Sadia H, Makai G, Bahadur A, Naeem W, Khan A. Virulent and multidrug-resistant Klebsiella pneumoniae from clinical samples in Balochistan. Int Wound J 2021; 18:510-518. [PMID: 33480117 PMCID: PMC8273605 DOI: 10.1111/iwj.13550] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 12/20/2020] [Accepted: 01/11/2021] [Indexed: 01/17/2023] Open
Abstract
Klebsiella pneumoniae is an important pathogen causing hospital-acquired infections in human beings. Samples from suspected patients of K pneumoniae associated with respiratory and urinary tract infections were collected at Bolan Medical Complex, Quetta, Balochistan. Clinical samples (n = 107) of urine and sputum were collected and processed for K pneumoniae isolation using selective culture media. Initially, 30 of 107 isolates resembling Klebsiella spp. were processed for biochemical profiling and molecular detection using gyrase A (gyrA) gene for conformation. The K pneumoniae isolates were analysed for the presence of drug resistance and virulence genes in their genomes. The 21 of 107 (19.6%) isolates were finally confirmed as K pneumoniae pathogens. An antibiogram study conducted against 17 different antibiotics showed that a majority of the isolates are multidrug resistant. All the isolates (100%) were resistant to amoxicillin, cefixime, amoxicillin-clavulanic acid, cefotaxime, and ceftriaxone followed by tetracycline (95.2%), ciprofloxacin and gentamicin (76.2%), sulphamethoxazol (66.7%), nalidixic acid (61.9%), norfloxacine (42.9%), piperacillin-tazobactam (23.8%), cefoperazone-sulbactam (19%), and cefotaxime-clavulanic acid (33.3%), whereas all the isolates showed sensitivity to amikacin, chloramphenicol, and imipenem. The presence of tetracycline, sulphamethoxazol-resistant genes, and extended-spectrum beta-lactamase was reconfirmed using different specific genes. The presence of virulence genes fimH1 and EntB responsible for adherence and enterobactin production was confirmed in the isolates. The high virulence and drug resistance potential of these Klebsiella isolates are of high public health concern. Multidrug resistance and virulence potential in K. pneumoniae are converting these nosocomial pathogens into superbugs and making its management harder.
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Affiliation(s)
- Sareeen Fatima
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Faiza Liaqat
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Ali Akbar
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Muhammad Sahfee
- CASVAB, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Abdul Samad
- CASVAB, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Muhammad Anwar
- Institute of Biochemistry, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Shazia Iqbal
- Department of ChemistryBalochistan University of Information Technology Engineering and Management SciencesQuettaPakistan
| | - Shabir Ahmad Khan
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Haleema Sadia
- Department of MicrobiologyBalochistan University of Information Technology Engineering and Management SciencesQuettaPakistan
| | - Gul Makai
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Anila Bahadur
- Department of Environmental ScienceSardar Bahadur Khan Women UniversityQuettaPakistan
| | - Wajeeha Naeem
- Department of Microbiology, Faculty of Life SciencesUniversity of BalochistanQuettaPakistan
| | - Adnan Khan
- Department of MicrobiologyUniversity of KarachiSindhPakistan
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11
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Saha P, Yeoh BS, Xiao X, Golonka RM, Abokor AA, Wenceslau CF, Shah YM, Joe B, Vijay-Kumar M. Enterobactin induces the chemokine, interleukin-8, from intestinal epithelia by chelating intracellular iron. Gut Microbes 2020; 12:1-18. [PMID: 33171063 PMCID: PMC7671005 DOI: 10.1080/19490976.2020.1841548] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Iron is an indispensable nutrient for both mammals and microbes. Bacteria synthesize siderophores to sequester host iron, whereas lipocalin 2 (Lcn2) is the host defense protein that prevent this iron thievery. Enterobactin (Ent) is a catecholate-type siderophore that has one of the strongest known affinities for iron. Intestinal epithelial cells (IECs) are adjacent to large microbial population and are in contact with microbial products, including Ent. We undertook this study to investigate whether a single stimulus of Ent could affect IEC functions. Using three human IEC cell-lines with differential basal levels of Lcn2 (i.e. HT29 < DLD-1 < Caco-2/BBe), we demonstrated that iron-free Ent could induce a dose-dependent secretion of the pro-inflammatory chemokine, interleukin 8 (IL-8), in HT29 and DLD-1 IECs, but not in Caco-2/BBe. Ent-induced IL-8 secretion was dependent on chelation of the labile iron pool and on the levels of intracellular Lcn2. Accordingly, IL-8 secretion by Ent-treated HT29 cells could be substantially inhibited by either saturating Ent with iron or by adding exogenous Lcn2 to the cells. IL-8 production by Ent could be further potentiated when co-stimulated with other microbial products (i.e. flagellin, lipopolysaccharide). Water-soluble microbial siderophores did not induce IL-8 production, which signifies that IECs are specifically responding to the lipid-soluble Ent. Intriguingly, formyl peptide receptor (FPR) antagonists (i.e. Boc2, cyclosporine H) abrogated Ent-induced IL-8, implicating that such IEC response could be, in part, dependent on FPR. Taken together, these results demonstrate that IECs sense Ent as a danger signal, where its recognition results in IL-8 secretion.
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Affiliation(s)
- Piu Saha
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Beng San Yeoh
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xia Xiao
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Rachel M. Golonka
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Ahmed A. Abokor
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Camilla F. Wenceslau
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Yatrik M. Shah
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI, USA,Division of Gastroenterology, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA,Rogel Cancer Center, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Bina Joe
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Matam Vijay-Kumar
- UT Microbiome Consortium, Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA,CONTACT Matam Vijay-Kumar Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH43614, USA
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12
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Estrada-Peña A, Cabezas-Cruz A, Obregón D. Resistance of Tick Gut Microbiome to Anti-Tick Vaccines, Pathogen Infection and Antimicrobial Peptides. Pathogens 2020; 9:E309. [PMID: 32331444 PMCID: PMC7238099 DOI: 10.3390/pathogens9040309] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/16/2020] [Accepted: 04/21/2020] [Indexed: 12/24/2022] Open
Abstract
Ixodes scapularis ticks harbor microbial communities including pathogenic and non-pathogenic microbes. Pathogen infection increases the expression of several tick gut proteins, which disturb the tick gut microbiota and impact bacterial biofilm formation. Anaplasma phagocytophilum induces ticks to express I. scapularis antifreeze glycoprotein (IAFGP), a protein with antimicrobial activity, while Borrelia burgdorferi induces the expression of PIXR. Here, we tested the resistance of I. scapularis microbiome to A. phagocytophilum infection, antimicrobial peptide IAFGP, and anti-tick immunity specific to PIXR. We demonstrate that A. phagocytophilum infection and IAFGP affect the taxonomic composition and taxa co-occurrence networks, but had limited impact on the functional traits of tick microbiome. In contrast, anti-tick immunity disturbed the taxonomic composition and the functional profile of tick microbiome, by increasing both the taxonomic and pathways diversity. Mechanistically, we show that anti-tick immunity increases the representation and importance of the polysaccharide biosynthesis pathways involved in biofilm formation, while these pathways are under-represented in the microbiome of ticks infected by A. phagocytophilum or exposed to IAFGP. These analyses revealed that tick microbiota is highly sensitive to anti-tick immunity, while it is less sensitive to pathogen infection and antimicrobial peptides. Results suggest that biofilm formation may be a defensive response of tick microbiome to anti-tick immunity.
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Affiliation(s)
- Agustín Estrada-Peña
- Faculty of Veterinary Medicine, University of Zaragoza, 50013 Zaragoza, Spain
- Group of Research on Emerging Zoonoses, Instituto Agroalimentario de Aragón (IA2), 50013 Zaragoza, Spain
| | - Alejandro Cabezas-Cruz
- UMR BIPAR, INRAE, ANSES, École Nationale Vétérinaire d’Alfort, Université Paris-Est, 94700 Maisons-Alfort, France
| | - Dasiel Obregón
- Center for Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, São Paulo 13400-970, Brazil
- School of Environmental Sciences, University of Guelph, Guelph, ON N1G 2W1, Canada
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Tan CAZ, Antypas H, Kline KA. Overcoming the challenge of establishing biofilms in vivo: a roadmap for Enterococci. Curr Opin Microbiol 2020; 53:9-18. [PMID: 32062025 DOI: 10.1016/j.mib.2020.01.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 12/28/2022]
Abstract
Enterococcus faecalis forms single and mixed-species biofilms on both tissue and medical devices in the host, often under exposure to fluid flow, giving rise to infections that are recalcitrant to treatment. The factors that drive enterococcal biofilm formation in the host, however, remain unclear. Recent reports in other pathogens show how surface sensing by bacteria can trigger the transition from planktonic to sessile lifestyle. Fluid flow can enhance initial adhesion, but also influence quorum sensing. Biofilm-specific factors, as well as biofilm size and extracellular polymeric substances, can compromise opsonization and phagocytosis. Bacterial interspecies synergy can create favorable conditions in the host for biofilm formation. Through these concepts, we define the knowledge gaps in understanding host-associated E. faecalis biofilm formation and propose a roadmap for future investigations.
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Affiliation(s)
- Casandra Ai Zhu Tan
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Haris Antypas
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore
| | - Kimberly A Kline
- Singapore Centre for Environmental Life Sciences Engineering, School of Biological Sciences, Nanyang Technological University, Singapore.
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Sahoo RK, Das A, Gaur M, Pattanayak A, Sahoo S, Debata NK, Rahman PK, Subudhi E. Genotypic validation of extended-spectrum β-lactamase and virulence factors in multidrug resistance Klebsiella pneumoniae in an Indian hospital. Pathog Glob Health 2019; 113:315-321. [PMID: 31865867 PMCID: PMC7006650 DOI: 10.1080/20477724.2019.1705020] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
The emergence of extended-spectrum β-lactamase (ESBL)-producing Klebsiella pneumoniae has been increasing rapidly across the world. The presence of virulence factors in ESBL producers further adds to the pathogenicity and severity of infection, which often complicate empirical therapy and sometimes result in treatment failures. In the present study, 227 non-repeated clinical isolates of K. pneumoniae obtained from different clinical specimens from a tertiary care hospital in India were analyzed to detect the genes responsible for ESBL production (blaTEM, blaCTX-M, and blaSHV), virulence (fimH-1, mrkD, entB, irp-1), and capsule production (K1-K2). Phenotypically identified 72 ESBL producing K. pneumoniae isolates were further subjected to PCR based genotypic analysis but only 20 were found to have at least one of the ESBL producing genes. blaTEM was the most predominant gene (100%), followed by blaSHV (90%), and blaCTX-M (85%). Similarly, the most common virulence genes were fimH-1 (70%), entB (65%), markD (55%), irp-1 (25%), K1 (25%), and K2 (20%). REP-PCR profile separated them into five major clusters (I-V), indicating the existing heterogeneity among the isolates. The resistance profile data obtained from the present study can serve as the information base to understand the infection pattern prevailing in the hospital and for physicians to recommend suitable antibiotics for the patients.
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Affiliation(s)
- Rajesh Kumar Sahoo
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Aradhana Das
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Mahendra Gaur
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Ankita Pattanayak
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Saubhagini Sahoo
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Nagen Kumar Debata
- Department of Microbiology, Institute of Medical Science and SUM Hospital, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
| | - Pattanathu K.S.M. Rahman
- Centre for Enzyme Innovation, Institute of Biomedical and Biomolecular Sciences, School of Biological Sciences, University of Portsmouth, Portsmouth, UK
| | - Enketeswara Subudhi
- Centre for Biotechnology, Siksha ‘O’ Anusandhan (Deemed to be University), Bhubaneswar, India
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15
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Vargas J, Moreno Mochi M, Nuñez J, Cáceres M, Mochi S, del Campo Moreno R, Jure M. Virulence factors and clinical patterns of multiple-clone hypermucoviscous KPC-2 producing K. pneumoniae. Heliyon 2019; 5:e01829. [PMID: 31286076 PMCID: PMC6587045 DOI: 10.1016/j.heliyon.2019.e01829] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/18/2019] [Accepted: 05/23/2019] [Indexed: 12/21/2022] Open
Abstract
Carbapenemase-producing Klebsiella pneumoniae (CRKP) are increasingly reported worldwide being necessary the local epidemiological monitoring. Our aim was to characterize the hypermucoviscous CRKP isolates collected in our hospital during a 6 months period. Carriage of the carbapenemase genes (bla KPC, bla NDM, bla VIM and bla OXA-48), extended spectrum β-lactamases (bla SHV-2, bla CTX-M) and the virulence genes (magA, k2A, rmpA, wabG, uge, allS, entB, ycfM, kpn, wcaG, fimH, mrkD, iutA, iroN, hly and cnf-1) were determined by multiplex-PCR. Genetic relationship among the isolates was performed by PFGE and MLST. A total of 35 isolates were recovered, being the urinary and respiratory tract the most common infection sites (34.2%). The bla KPC-2 gene was present in all the isolates, coexisting with bla CTX-M-2 (45.7%), bla SHV-2 (28.6%), and bla CTX-M-2/bla SHV-2 (14.3%). The capsular serotype K2 corresponded with 68.6% of the isolates. Virulence factors frequency were variable [adhesins (97.1%), siderophores (94.3%) and phagocytosis resistance (wabG 48.5%, uge 80% and ycfM 57.1%)]. A total of 10 STs were identified although 40% of them clustered on ST25-CC65, and 17% to ST17. The incidence of KPC-2-producing K. pneumoniae reported by the hospital was 0.290 per 1000 admissions. In summary we described an epidemic scenario of multidrug resistant hypermucoviscous KPC-2 producing ST25 K. pneumoniae in our institution.
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Affiliation(s)
- J.M. Vargas
- Universidad Nacional de Tucumán, Facultad de Bioquímica, Química y Farmacia, Instituto de Microbiología Luis C. Verna, Cátedra de Bacteriología, Laboratorio de Antimicrobianos, Ayacucho 471, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
| | - M.P. Moreno Mochi
- Universidad Nacional de Tucumán, Facultad de Bioquímica, Química y Farmacia, Instituto de Microbiología Luis C. Verna, Cátedra de Bacteriología, Laboratorio de Antimicrobianos, Ayacucho 471, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
| | - J.M. Nuñez
- Hospital Ángel C. Padilla, Departamento de Infectología, Alberdi 550, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
| | - M. Cáceres
- Hospital Ángel C. Padilla, Servicio de Bacteriología, Alberdi 550, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
| | - S. Mochi
- Hospital Ángel C. Padilla, Servicio de Bacteriología, Alberdi 550, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
| | - R. del Campo Moreno
- Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Servicio de Microbiología y Parasitología del Hospital Universitario Ramón y Cajal de Madrid, Ctra. Colmenar Viejo, km. 9100, CP 28034, Madrid, Spain
| | - M.A. Jure
- Universidad Nacional de Tucumán, Facultad de Bioquímica, Química y Farmacia, Instituto de Microbiología Luis C. Verna, Cátedra de Bacteriología, Laboratorio de Antimicrobianos, Ayacucho 471, CP:4000, San Miguel de Tucumán, Tucumán, Argentina
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16
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Saha P, Xiao X, Yeoh BS, Chen Q, Katkere B, Kirimanjeswara GS, Vijay-Kumar M. The bacterial siderophore enterobactin confers survival advantage to Salmonella in macrophages. Gut Microbes 2018; 10:412-423. [PMID: 30449241 PMCID: PMC6546333 DOI: 10.1080/19490976.2018.1546519] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 08/31/2018] [Accepted: 10/30/2018] [Indexed: 02/03/2023] Open
Abstract
Enterobactin (Ent), a prototypical bacterial siderophore known for its unparalleled affinity for iron, is widely conserved among members of the Enterobacteriaceae family of Gram-negative bacteria. In this study, we demonstrated that, aside from mediating iron acquisition, Ent also dampened the macrophages (MΦs) antimicrobial responses against intracellular infection by Salmonella enterica serovar Typhimurium. Accordingly, the loss of Ent expression (ΔentB) in Salmonella demoted their survivability against MΦs. Addition of exogenous Ent not only rescued the survival of ΔentB Salmonella, but also augmented WT Salmonella to better withstand the microbicidal activity of MΦs. The protection conferred to WT Salmonella was observed only when Ent was administered as iron-free, thus indicating the requirement of iron chelation in this context. In contrast, the exogenous iron-bound Ent retained its ability to promote the survival of ΔentB Salmonella, albeit modestly. Assessment on MΦs labile iron pool (LIP) revealed that iron-free Ent is able to permeate into MΦs, chelate the intracellular LIP, and regulate the expression of several key iron-regulatory proteins, i.e., divalent metal transporter 1, ferroportin, and hepcidin. Chelation of iron by Ent was also observed to promote the MΦs towards M2 polarization. Collectively, our findings demonstrated that Ent not only facilitates bacterial iron uptake but also disrupts MΦs iron homeostasis and M1/M2 polarization to safeguard intracellular bacteria against the anti-bacterial effects of their host.
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Affiliation(s)
- Piu Saha
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xia Xiao
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Beng San Yeoh
- Graduate Program in Immunology & Infectious Disease, Pennsylvania State University, University Park, PA, USA
| | - Qiuyan Chen
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Bhuvana Katkere
- Department of Veterinary and Biomedical Sciences, The Pennsylvania State University, University Park, PA, USA
| | | | - Matam Vijay-Kumar
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
- Department of Medical Microbiology & Immunology, University of Toledo, Toledo, OH, USA
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17
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Hamzaoui Z, Ocampo-Sosa A, Fernandez Martinez M, Landolsi S, Ferjani S, Maamar E, Saidani M, Slim A, Martinez-Martinez L, Boutiba-Ben Boubaker I. Role of association of OmpK35 and OmpK36 alteration and bla ESBL and/or bla AmpC genes in conferring carbapenem resistance among non-carbapenemase-producing Klebsiella pneumoniae. Int J Antimicrob Agents 2018; 52:898-905. [PMID: 29621592 DOI: 10.1016/j.ijantimicag.2018.03.020] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 03/01/2018] [Accepted: 03/28/2018] [Indexed: 12/16/2022]
Abstract
In Klebsiella pneumoniae, loss of the two major outer membrane porins (OMPs) OmpK35 and OmpK36 confers resistance to carbapenems in strains producing extended-spectrum β-lactamases (ESBLs) or plasmid-mediated AmpC-type β-lactamases. This study investigated mechanisms responsible for carbapenem resistance in non-carbapenemase-producing K. pneumoniae (NCPK). All carbapenem-resistant Enterobacteriaceae (CRE) at Charles Nicolle Hospital (Tunis, Tunisia) were collected over a 6-year period (2010-2015). Among the 334 CRE strains collected, 44 (13.2%) were NCPK. MIC ranges for ertapenem, imipenem and meropenem were 1 to >32 mg/L, 0.125-8 mg/L and 0.125-32 mg/L, respectively. All strains showed a multidrug-resistant (MDR) phenotype and were negative for carbapenemase activity. None of the carbapenemase genes searched for were found. ESBL production was confirmed in all isolates except one [CTX-M-15 (n = 39) and SHV-5 (n = 4)]. Three isolates produce DHA-1 (associated with CTX-M-15 in two strains). Molecular fingerprints grouped the 44 NCPK isolates into seven clusters. In seven representative strains of these clusters, SDS-PAGE results showed that four isolates lacked the OmpK35 porin, one isolate lacked OmpK36 and two isolates lacked both OmpK35 and OmpK36. Sequencing of the corresponding porin genes showed amino acid insertions and deletions leading to early termination of translation, point mutations in the promoter region, or insertion sequences disrupting the gene coding sequence. Loss or deficiency of OMPs, coupled with ESBL and/or AmpC production, plays an important role in conferring carbapenem resistance in K. pneumoniae. Dissemination of these MDR bacteria in our hospital may create serious therapeutic problems in the future.
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Affiliation(s)
- Zaineb Hamzaoui
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia; University of Carthage, Faculty of Sciences of Bizerte, Tunis, Tunisia.
| | - Alain Ocampo-Sosa
- Service of Microbiology, University Hospital Marqués de Valdecilla-IDIVAL, Santander 39008, Spain
| | - Marta Fernandez Martinez
- Service of Microbiology, University Hospital Marqués de Valdecilla-IDIVAL, Santander 39008, Spain
| | - Sarrah Landolsi
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia
| | - Sana Ferjani
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia; University of Carthage, Faculty of Sciences of Bizerte, Tunis, Tunisia
| | - Elaa Maamar
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia
| | - Mabrouka Saidani
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, 1006 Tunis, Tunisia
| | - Amine Slim
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, 1006 Tunis, Tunisia
| | - Luis Martinez-Martinez
- Clinical Unit of Microbiology, University Hospital Reina Sofía, Córdoba, Spain; Department of Microbiology, University of Córdoba, Córdoba, Spain; Instituto Maimónides de Investigación Biomédica de Córdoba (IMIBIC), Córdoba, Spain
| | - Ilhem Boutiba-Ben Boubaker
- University of Tunis El Manar, Faculty of Medicine of Tunis, LR99ES09 Research Laboratory 'Antimicrobial resistance', 1007 Tunis, Tunisia; Charles Nicolle Hospital, Laboratory of Microbiology, 1006 Tunis, Tunisia
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Balikó G, Vernyik V, Karcagi I, Györfy Z, Draskovits G, Fehér T, Pósfai G. Rational Efforts to Streamline the Escherichia coliGenome. Synth Biol (Oxf) 2018. [DOI: 10.1002/9783527688104.ch4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Gabriella Balikó
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Viktor Vernyik
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Ildikó Karcagi
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Zsuzsanna Györfy
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Gábor Draskovits
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - Tamás Fehér
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
| | - György Pósfai
- Biological Research Centre of the Hungarian Academy of Sciences; Institute of Biochemistry, Synthetic and Systems Biology Unit; Temesvari krt. 62 Szeged 6726 Hungary
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Tada T, Uechi K, Nakasone I, Miyazato Z, Shinzato T, Shimada K, Tsuchiya M, Kirikae T, Fujita J. A hemin auxotrophic Enterobacter cloacae clinical isolate with increased resistance to carbapenems and aminoglycosides. J Med Microbiol 2017; 67:29-32. [PMID: 29205135 DOI: 10.1099/jmm.0.000655] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Small-colony variants (SCVs) were obtained from an Enterobacter cloacae clinical isolate in Okinawa, Japan. One variant showed auxotrophy for hemin with a deletion of 20 365 nucleotides, dosC-ydiK-mmuP-mmuM-tauA-tauB-tauC-tauD-hemB-yaiT-yaiV-ampH-yddQ-sbmA-yaiW-yaiY-yaiZ, including hemB, and was more resistant to aminoglycosides and carbapenems, but more susceptible to aztreonam, than the parent strain.
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Affiliation(s)
- Tatsuya Tada
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan.,Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kohei Uechi
- Division of Clinical Laboratory and Blood Transfusion, University Hospital of the Ryukyus, Okinawa, Japan.,Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
| | - Isamu Nakasone
- Control and Prevention of Infectious Disease, University Hospital of the Ryukyus, Okinawa, Japan
| | | | | | - Kayo Shimada
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Mitsuhiro Tsuchiya
- Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Teruo Kirikae
- Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan.,Department of Microbiology, Juntendo University School of Medicine, Tokyo, Japan
| | - Jiro Fujita
- Department of Infectious Diseases, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan
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20
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Biofilm Formation Potential of Heat-Resistant Escherichia coli Dairy Isolates and the Complete Genome of Multidrug-Resistant, Heat-Resistant Strain FAM21845. Appl Environ Microbiol 2017; 83:AEM.00628-17. [PMID: 28550056 PMCID: PMC5514686 DOI: 10.1128/aem.00628-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/18/2017] [Indexed: 02/07/2023] Open
Abstract
We tested the biofilm formation potential of 30 heat-resistant and 6 heat-sensitive Escherichia coli dairy isolates. Production of curli and cellulose, static biofilm formation on polystyrene (PS) and stainless steel surfaces, biofilm formation under dynamic conditions (Bioflux), and initial adhesion rates (IAR) were evaluated. Biofilm formation varied greatly between strains, media, and assays. Our results highlight the importance of the experimental setup in determining biofilm formation under conditions of interest, as correlation between different assays was often not a given. The heat-resistant, multidrug-resistant (MDR) strain FAM21845 showed the strongest biofilm formation on PS and the highest IAR and was the only strain that formed significant biofilms on stainless steel under conditions relevant to the dairy industry, and it was therefore fully sequenced. Its chromosome is 4.9 Mb long, and it harbors a total of five plasmids (147.2, 54.2, 5.8, 2.5, and 1.9 kb). The strain carries a broad range of genes relevant to antimicrobial resistance and biofilm formation, including some on its two large conjugative plasmids, as demonstrated in plate mating assays.IMPORTANCE In biofilms, cells are embedded in an extracellular matrix that protects them from stresses, such as UV radiation, osmotic shock, desiccation, antibiotics, and predation. Biofilm formation is a major bacterial persistence factor of great concern in the clinic and the food industry. Many tested strains formed strong biofilms, and especially strains such as the heat-resistant, MDR strain FAM21845 may pose a serious issue for food production. Strong biofilm formation combined with diverse resistances (some encoded on conjugative plasmids) may allow for increased persistence, coselection, and possible transfer of these resistance factors. Horizontal gene transfer may conceivably occur in the food production setting or the gastrointestinal tract after consumption.
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Saha P, Yeoh BS, Olvera RA, Xiao X, Singh V, Awasthi D, Subramanian BC, Chen Q, Dikshit M, Wang Y, Parent CA, Vijay-Kumar M. Bacterial Siderophores Hijack Neutrophil Functions. THE JOURNAL OF IMMUNOLOGY 2017; 198:4293-4303. [PMID: 28432145 DOI: 10.4049/jimmunol.1700261] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 03/22/2017] [Indexed: 12/21/2022]
Abstract
Neutrophils are the primary immune cells that respond to inflammation and combat microbial transgression. To thrive, the bacteria residing in their mammalian host have to withstand the antibactericidal responses of neutrophils. We report that enterobactin (Ent), a catecholate siderophore expressed by Escherichia coli, inhibited PMA-induced generation of reactive oxygen species (ROS) and neutrophil extracellular traps (NETs) in mouse and human neutrophils. Ent also impaired the degranulation of primary granules and inhibited phagocytosis and bactericidal activity of neutrophils, without affecting their migration and chemotaxis. Molecular analysis revealed that Ent can chelate intracellular labile iron that is required for neutrophil oxidative responses. Other siderophores (pyoverdine, ferrichrome, deferoxamine) likewise inhibited ROS and NETs in neutrophils, thus indicating that the chelation of iron may largely explain their inhibitory effects. To counter iron theft by Ent, neutrophils rely on the siderophore-binding protein lipocalin 2 (Lcn2) in a "tug-of-war" for iron. The inhibition of neutrophil ROS and NETs by Ent was augmented in Lcn2-deficient neutrophils compared with wild-type neutrophils but was rescued by the exogenous addition of recombinant Lcn2. Taken together, our findings illustrate the novel concept that microbial siderophore's iron-scavenging property may serve as an antiradical defense system that neutralizes the immune functions of neutrophils.
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Affiliation(s)
- Piu Saha
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Beng San Yeoh
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Rodrigo A Olvera
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Xia Xiao
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Vishal Singh
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Deepika Awasthi
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Bhagawat C Subramanian
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Qiuyan Chen
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802
| | - Madhu Dikshit
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Yanming Wang
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802; and
| | - Carole A Parent
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Matam Vijay-Kumar
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802; .,Department of Medicine, The Pennsylvania State University Medical Center, Hershey, PA 17033
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Li B, Li N, Yue Y, Liu X, Huang Y, Gu L, Xu S. An unusual crystal structure of ferric-enterobactin bound FepB suggests novel functions of FepB in microbial iron uptake. Biochem Biophys Res Commun 2016; 478:1049-53. [PMID: 27539322 DOI: 10.1016/j.bbrc.2016.08.036] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 08/05/2016] [Indexed: 11/16/2022]
Abstract
Iron acquisition by siderophores is critical for the survival of most bacteria. Enterobactin is a kind of catechol siderophore that exhibits the highest affinity to iron atoms secreted by E. coli and several other species of Enterobacteriaceae. The periplasmic binding protein (PBP) FepB can transport ferric-enterobactin (Fe-Ent) from the outer membrane to the membrane-associated ATP-binding cassette transport system in E. coli. To elucidate this process, we solved the crystal structure of FepB in complex with Fe-Ent at a resolution of 1.8 Å. Consistent with previously reported NMR results, our crystal structure shows that, similar to the other type III PBPs, the FepB structure was folded with separated globular N- and C-termini linked by a long α-helix. Additionally, the structure showed that the Fe-Ent bound to the cleft between the N- and C-terminal domains. Exceptionally, FepB differs from the other known siderophore binding PBPs in that it forms a trimer by capturing four Fe-Ents that can each contribute to FepB trimerization. Dynamic light-scattering experiments are consistent with the structural observations and indicate that FepB forms a trimer in a Fe-Ent-dependent manner.
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Affiliation(s)
- Bingqing Li
- Key Laboratory of Rare and Uncommon Diseases, Department of Microbiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan 250062, China; State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China.
| | - Ning Li
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China
| | - Yingying Yue
- Key Laboratory of Rare and Uncommon Diseases, Department of Microbiology, Institute of Basic Medicine, Shandong Academy of Medical Sciences, Jinan 250062, China
| | - Xiuhua Liu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China
| | - Yan Huang
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China
| | - Lichuan Gu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China
| | - Sujuan Xu
- State Key Laboratory of Microbial Technology, School of Life Sciences, Shandong University, Jinan 250100, China.
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Ahmed AJA, Alaa HAA. Virulence factors and antibiotic susceptibility patterns of multidrug resistance Klebsiella pneumoniae isolated from different clinical infections. ACTA ACUST UNITED AC 2016. [DOI: 10.5897/ajmr2016.8051] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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24
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Branduardi P. Synthetic Biology for Cellular Remodelling to Elicit Industrially Relevant Microbial Phenotypes. Synth Biol (Oxf) 2016. [DOI: 10.1007/978-3-319-22708-5_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Amaya-Gómez CV, Hirsch AM, Soto MJ. Biofilm formation assessment in Sinorhizobium meliloti reveals interlinked control with surface motility. BMC Microbiol 2015; 15:58. [PMID: 25887945 PMCID: PMC4381460 DOI: 10.1186/s12866-015-0390-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 02/18/2015] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Swarming motility and biofilm formation are opposite, but related surface-associated behaviors that allow various pathogenic bacteria to colonize and invade their hosts. In Sinorhizobium meliloti, the alfalfa endosymbiont, these bacterial processes and their relevance for host plant colonization are largely unexplored. Our previous work demonstrated distinct swarming abilities in two S. meliloti strains (Rm1021 and GR4) and revealed that both environmental cues (iron concentration) and bacterial genes (fadD, rhb, rirA) play crucial roles in the control of surface motility in this rhizobial species. In the current study, we investigate whether these factors have an impact on the ability of S. meliloti to establish biofilms and to colonize host roots. RESULTS We found that strain GR4, which is less prone to translocate on solid surfaces than strain Rm1021, is more efficient in developing biofilms on glass and plant root surfaces. High iron conditions, known to prevent surface motility in a wild-type strain of S. meliloti, promote biofilm development in Rm1021 and GR4 strains by inducing the formation of more structured and thicker biofilms than those formed under low iron levels. Moreover, three different S. meliloti mutants (fadD, rhb, and rirA) that exhibit an altered surface translocation behavior compared with the wild-type strain, establish reduced biofilms on both glass and alfalfa root surfaces. Iron-rich conditions neither rescue the defect in biofilm formation shown by the rhb mutant, which is unable to produce the siderophore rhizobactin 1021 (Rhb1021), nor have any impact on biofilms formed by the iron-response regulator rirA mutant. On the other hand, S. meliloti FadD loss-of-function mutants do not establish normal biofilms irrespective of iron levels. CONCLUSIONS Our studies show that siderophore Rhb1021 is not only required for surface translocation, but also for biofilm formation on glass and root surfaces by strain Rm1021. In addition, we present evidence for the existence of control mechanisms that inversely regulate swarming and biofilm formation in S. meliloti, and that contribute to efficient plant root colonization. One of these mechanisms involves iron levels and the iron global regulator RirA. The other mechanism involves the participation of the fatty acid metabolism-related enzyme FadD.
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Affiliation(s)
- Carol V Amaya-Gómez
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Profesor Albareda 1, 18008, Granada, Spain.
| | - Ann M Hirsch
- Department of Molecular, Cell, and Developmental Biology and Molecular Biology Institute, University of California-Los Angeles, Los Angeles, CA, 90095-1606, USA.
| | - María J Soto
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Profesor Albareda 1, 18008, Granada, Spain.
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Virulence profiles and antibiotic susceptibility patterns of Klebsiella pneumoniae strains isolated from different clinical specimens. ACTA ACUST UNITED AC 2013; 61:209-16. [DOI: 10.1016/j.patbio.2012.10.004] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2012] [Accepted: 10/30/2012] [Indexed: 11/20/2022]
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Frangipani E, Visaggio D, Heeb S, Kaever V, Cámara M, Visca P, Imperi F. The Gac/Rsm and cyclic-di-GMP signalling networks coordinately regulate iron uptake in Pseudomonas aeruginosa. Environ Microbiol 2013; 16:676-88. [PMID: 23796404 DOI: 10.1111/1462-2920.12164] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 05/20/2013] [Accepted: 05/25/2013] [Indexed: 01/09/2023]
Abstract
Pseudomonas aeruginosa is a versatile bacterial pathogen capable of occupying diverse ecological niches. To cope with iron limitation, P. aeruginosa secretes two siderophores, pyoverdine and pyochelin, whose ability to deliver iron to the cell is crucial for biofilm formation and pathogenicity. In this study, we describe a link between iron uptake and the Gac/Rsm system, a conserved signal transducing pathway of P. aeruginosa that controls the production of extracellular products and virulence factors, as well as the switch from planktonic to biofilm lifestyle. We have observed that pyoverdine and pyochelin production in P. aeruginosa is strongly dependent on the activation state of the Gac/Rsm pathway, which controls siderophore regulatory and biosynthetic genes at the transcriptional level, in a manner that does not involve regulation of ferric uptake regulator (Fur) expression. Gac/Rsm-mediated regulation of iron uptake genes appears to be conserved in different P. aeruginosa strains. Further experiments led to propose that the Gac/Rsm system regulates siderophore production through modulation of the intracellular levels of the second messenger c-di-GMP, indicating that the c-di-GMP and the Gac/Rsm regulatory networks essential for biofilm formation can also coordinately control iron uptake in P. aeruginosa.
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Leprince A, van Passel MWJ, dos Santos VAPM. Streamlining genomes: toward the generation of simplified and stabilized microbial systems. Curr Opin Biotechnol 2012; 23:651-8. [DOI: 10.1016/j.copbio.2012.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 05/01/2012] [Accepted: 05/02/2012] [Indexed: 02/07/2023]
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