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Schüler MA, Riedel T, Overmann J, Daniel R, Poehlein A. Comparative genome analyses of clinical and non-clinical Clostridioides difficile strains. Front Microbiol 2024; 15:1404491. [PMID: 38993487 PMCID: PMC11238072 DOI: 10.3389/fmicb.2024.1404491] [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: 03/21/2024] [Accepted: 06/05/2024] [Indexed: 07/13/2024] Open
Abstract
The pathogenic bacterium Clostridioides difficile is a worldwide health burden with increasing morbidity, mortality and antibiotic resistances. Therefore, extensive research efforts are made to unravel its virulence and dissemination. One crucial aspect for C. difficile is its mobilome, which for instance allows the spread of antibiotic resistance genes (ARG) or influence strain virulence. As a nosocomial pathogen, the majority of strains analyzed originated from clinical environments and infected individuals. Nevertheless, C. difficile can also be present in human intestines without disease development or occur in diverse environmental habitats such as puddle water and soil, from which several strains could already be isolated. We therefore performed comprehensive genome comparisons of closely related clinical and non-clinical strains to identify the effects of the clinical background. Analyses included the prediction of virulence factors, ARGs, mobile genetic elements (MGEs), and detailed examinations of the pan genome. Clinical-related trends were thereby observed. While no significant differences were identified in fundamental C. difficile virulence factors, the clinical strains carried more ARGs and MGEs, and possessed a larger accessory genome. Detailed inspection of accessory genes revealed higher abundance of genes with unknown function, transcription-associated, or recombination-related activity. Accessory genes of these functions were already highlighted in other studies in association with higher strain virulence. This specific trend might allow the strains to react more efficiently on changing environmental conditions in the human host such as emerging stress factors, and potentially increase strain survival, colonization, and strain virulence. These findings indicated an adaptation of the strains to the clinical environment. Further, implementation of the analysis results in pairwise genome comparisons revealed that the majority of these accessory genes were encoded on predicted MGEs, shedding further light on the mobile genome of C. difficile. We therefore encourage the inclusion of non-clinical strains in comparative analyses.
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Affiliation(s)
- Miriam A. Schüler
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University, Göttingen, Germany
| | - Thomas Riedel
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Braunschweig-Hannover, Braunschweig, Germany
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- German Center for Infection Research (DZIF), Partner Site Braunschweig-Hannover, Braunschweig, Germany
- Institute of Microbiology, Technische Universität Braunschweig, Braunschweig, Germany
| | - Rolf Daniel
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University, Göttingen, Germany
| | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University, Göttingen, Germany
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Alam MZ, Madan R. Clostridioides difficile Toxins: Host Cell Interactions and Their Role in Disease Pathogenesis. Toxins (Basel) 2024; 16:241. [PMID: 38922136 PMCID: PMC11209539 DOI: 10.3390/toxins16060241] [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: 04/17/2024] [Revised: 05/20/2024] [Accepted: 05/22/2024] [Indexed: 06/27/2024] Open
Abstract
Clostridioides difficile, a Gram-positive anaerobic bacterium, is the leading cause of hospital-acquired antibiotic-associated diarrhea worldwide. The severity of C. difficile infection (CDI) varies, ranging from mild diarrhea to life-threatening conditions such as pseudomembranous colitis and toxic megacolon. Central to the pathogenesis of the infection are toxins produced by C. difficile, with toxin A (TcdA) and toxin B (TcdB) as the main virulence factors. Additionally, some strains produce a third toxin known as C. difficile transferase (CDT). Toxins damage the colonic epithelium, initiating a cascade of cellular events that lead to inflammation, fluid secretion, and further tissue damage within the colon. Mechanistically, the toxins bind to cell surface receptors, internalize, and then inactivate GTPase proteins, disrupting the organization of the cytoskeleton and affecting various Rho-dependent cellular processes. This results in a loss of epithelial barrier functions and the induction of cell death. The third toxin, CDT, however, functions as a binary actin-ADP-ribosylating toxin, causing actin depolymerization and inducing the formation of microtubule-based protrusions. In this review, we summarize our current understanding of the interaction between C. difficile toxins and host cells, elucidating the functional consequences of their actions. Furthermore, we will outline how this knowledge forms the basis for developing innovative, toxin-based strategies for treating and preventing CDI.
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Affiliation(s)
- Md Zahidul Alam
- Department of Pathology and Laboratory Medicine, Brody School of Medicine, East Carolina University, 600 Moye Boulevard, Greenville, NC 27858, USA
| | - Rajat Madan
- Division of Infectious Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA;
- Veterans Affairs Medical Center, Cincinnati, OH 45220, USA
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Schüler MA, Daniel R, Poehlein A. Novel insights into phage biology of the pathogen Clostridioides difficile based on the active virome. Front Microbiol 2024; 15:1374708. [PMID: 38577680 PMCID: PMC10993401 DOI: 10.3389/fmicb.2024.1374708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 02/27/2024] [Indexed: 04/06/2024] Open
Abstract
The global pathogen Clostridioides difficile is a well-studied organism, and researchers work on unraveling its fundamental virulence mechanisms and biology. Prophages have been demonstrated to influence C. difficile toxin expression and contribute to the distribution of advantageous genes. All these underline the importance of prophages in C. difficile virulence. Although several C. difficile prophages were sequenced and characterized, investigations on the entire active virome of a strain are still missing. Phages were mainly isolated after mitomycin C-induction, which does not resemble a natural stressor for C. difficile. We examined active prophages from different C. difficile strains after cultivation in the absence of mitomycin C by sequencing and characterization of particle-protected DNA. Phage particles were collected after standard cultivation, or after cultivation in the presence of the secondary bile salt deoxycholate (DCA). DCA is a natural stressor for C. difficile and a potential prophage-inducing agent. We also investigated differences in prophage activity between clinical and non-clinical C. difficile strains. Our experiments demonstrated that spontaneous prophage release is common in C. difficile and that DCA presence induces prophages. Fourteen different, active phages were identified by this experimental procedure. We could not identify a definitive connection between clinical background and phage activity. However, one phage exhibited distinctively higher activity upon DCA induction in the clinical strain than in the corresponding non-clinical strain, although the phage is identical in both strains. We recorded that enveloped DNA mapped to genome regions with characteristics of mobile genetic elements other than prophages. This pointed to mechanisms of DNA mobility that are not well-studied in C. difficile so far. We also detected phage-mediated lateral transduction of bacterial DNA, which is the first described case in C. difficile. This study significantly contributes to our knowledge of prophage activity in C. difficile and reveals novel aspects of C. difficile (phage) biology.
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Affiliation(s)
| | | | - Anja Poehlein
- Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August-University Göttingen, Göttingen, Germany
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Schüler MA, Schneider D, Poehlein A, Daniel R. Culture-independent detection of low-abundant Clostridioides difficile in environmental DNA via PCR. Appl Environ Microbiol 2024; 90:e0127823. [PMID: 38334406 PMCID: PMC10952401 DOI: 10.1128/aem.01278-23] [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: 07/24/2023] [Accepted: 12/21/2023] [Indexed: 02/10/2024] Open
Abstract
Clostridioides difficile represents a major burden to public health. As a well-known nosocomial pathogen whose occurrence is highly associated with antibiotic treatment, most examined C. difficile strains originated from clinical specimen and were isolated under selective conditions employing antibiotics. This suggests a significant bias among analyzed C. difficile strains, which impedes a holistic view on this pathogen. In order to support extensive isolation of C. difficile strains from environmental samples, we designed a detection PCR that targets the hpdBCA-operon and thereby identifies low abundances of C. difficile in environmental samples. This operon encodes the 4-hydroxyphenylacetate decarboxylase, which catalyzes the production of the antimicrobial compound para-cresol. Amplicon-based analyses of diverse environmental samples demonstrated that the designed PCR is highly specific for C. difficile and successfully detected C. difficile despite its absence in general 16S rRNA gene-based detection strategies. Further analyses revealed the potential of the hpdBCA detection PCR sequence for initial phylogenetic classification, which allows assessment of C. difficile diversity in environmental samples via amplicon sequencing. Our findings furthermore showed that C. difficile strains isolated under antibiotic treatment from environmental samples were originally dominated by other strains according to PCR amplicon results. This provided evidence for selective cultivation of under-represented but antibiotic-resistant isolates. Thereby, we revealed a substantial bias in C. difficile isolation and research.IMPORTANCEClostridioides difficile is a main cause of diarrheic infections after antibiotic treatment with serious morbidity and mortality worldwide. Research on this pathogen and its virulence has focused on bacterial isolation from clinical specimens under antibiotic treatment, which implies a substantial bias in isolated strains. Comprehensive studies, however, require an unbiased strain collection, which is accomplished by isolation of C. difficile from diverse environmental samples and avoidance of antibiotic-based enrichment strategies. Thus, isolation can significantly benefit from our C. difficile-specific detection PCR, which rapidly verifies C. difficile presence in environmental samples and further allows estimation of the C. difficile diversity by using next-generation sequencing.
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Affiliation(s)
- Miriam A. Schüler
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Dominik Schneider
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology and Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, University of Göttingen, Göttingen, Germany
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Lin Q, Li Z, Ke H, Fei J, Zhang T, Wang P, Chen Y. Linked mutations within the pathogenicity locus of Clostridioides difficile increase virulence. Infect Dis (Lond) 2023; 55:847-856. [PMID: 37615633 DOI: 10.1080/23744235.2023.2249551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 08/14/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND The clinical manifestations of Clostridioides difficile infections range from diarrhoea to pseudomembranous colitis (PMC) and death. We evaluated the association between gene content in C. difficile clinical isolates and disease severity. METHODS Fifty-three C. difficile isolates were subjected to Sanger sequencing, clinical data were used to analyse the association of gene content with disease severity, and 83 non-duplicate isolates were collected to confirm the results. Virulence was further examined by functional in vitro and in vivo experiments. RESULTS Among the 53 C. difficile isolates, ribotypes 017 (n = 9, 17.0%) and 012 (n = 8, 15.1%) were predominant. Fifteen strains exhibited a correlation between mutations of pathogenicity locus genes (tcdB, tcdC, tcdR, and tcdE) and were named linked-mutation strains. Ribotypes are not associated with clinical PMC and Linked-mutation strains. The proportion of patients with PMC was higher in the group infected with linked-mutation strains than in the non-linked-mutation group (57.14% vs. 0%, p < 0.001). The linked-mutation rate of C. difficile was higher in patients with PMC than in patients without PMC (89.47% vs. 7.8%, p < 0.0001). Linked-mutation strains showed greater cytotoxicity in vitro and caused more severe tissue damage in a mouse model. CONCLUSIONS Linked-mutation strains are associated with high virulence and PMC development. This result will help monitor the clinical prognosis of C. difficile infection and provide key insights for developing therapeutic targets and monoclonal antibodies.
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Affiliation(s)
- Qianyun Lin
- Department of Gastroenterology, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Zitong Li
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Haoran Ke
- Hepatology Unit, Department of Infectious Diseases, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiaxi Fei
- Graceland Medical Center, the, Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Ting Zhang
- Department of Gastroenterology, the Third Affiliated Hospital of Southern Medical University, Guangzhou, China
| | - Pu Wang
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Ye Chen
- Guangdong Provincial Key Laboratory of Gastroenterology, Department of Gastroenterology, Nanfang Hospital, Southern Medical University, Guangzhou, China
- Integrative Microecology Center, Department of Gastroenterology, Shenzhen Hospital, Southern Medical University, Shenzhen, China
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6
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Dong Q, Lin H, Allen MM, Garneau JR, Sia JK, Smith RC, Haro F, McMillen T, Pope RL, Metcalfe C, Burgo V, Woodson C, Dylla N, Kohout C, Sundararajan A, Snitkin ES, Young VB, Fortier LC, Kamboj M, Pamer EG. Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile. Cell Rep 2023; 42:112861. [PMID: 37523264 PMCID: PMC10627504 DOI: 10.1016/j.celrep.2023.112861] [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: 01/23/2023] [Revised: 05/01/2023] [Accepted: 07/07/2023] [Indexed: 08/02/2023] Open
Abstract
Clostridioides difficile produces toxins that damage the colonic epithelium, causing colitis. Variation in disease severity is poorly understood and has been attributed to host factors and virulence differences between C. difficile strains. We test 23 epidemic ST1 C. difficile clinical isolates for their virulence in mice. All isolates encode a complete Tcd pathogenicity locus and achieve similar colonization densities. However, disease severity varies from lethal to avirulent infections. Genomic analysis of avirulent isolates reveals a 69-bp deletion in the cdtR gene, which encodes a response regulator for binary toxin expression. Deleting the 69-bp sequence in virulent R20291 strain renders it avirulent in mice with reduced toxin gene transcription. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile isolates without reducing colonization and persistence. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.
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Affiliation(s)
- Qiwen Dong
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA.
| | - Huaiying Lin
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Marie-Maude Allen
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Julian R Garneau
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Jonathan K Sia
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rita C Smith
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Fidel Haro
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Tracy McMillen
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Rosemary L Pope
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
| | - Carolyn Metcalfe
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Victoria Burgo
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Che Woodson
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Nicholas Dylla
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | - Claire Kohout
- Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA
| | | | - Evan S Snitkin
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vincent B Young
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Mini Kamboj
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Eric G Pamer
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Duchossois Family Institute, University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, University of Chicago, Chicago, IL 60637, USA
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7
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Caballero-Flores G, Pickard JM, Núñez G. Microbiota-mediated colonization resistance: mechanisms and regulation. Nat Rev Microbiol 2023; 21:347-360. [PMID: 36539611 PMCID: PMC10249723 DOI: 10.1038/s41579-022-00833-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 53.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/16/2022] [Indexed: 12/24/2022]
Abstract
A dense and diverse microbial community inhabits the gut and many epithelial surfaces. Referred to as the microbiota, it co-evolved with the host and is beneficial for many host physiological processes. A major function of these symbiotic microorganisms is protection against pathogen colonization and overgrowth of indigenous pathobionts. Dysbiosis of the normal microbial community increases the risk of pathogen infection and overgrowth of harmful pathobionts. The protective mechanisms conferred by the microbiota are complex and include competitive microbial-microbial interactions and induction of host immune responses. Pathogens, in turn, have evolved multiple strategies to subvert colonization resistance conferred by the microbiota. Understanding the mechanisms by which microbial symbionts limit pathogen colonization should guide the development of new therapeutic approaches to prevent or treat disease.
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Affiliation(s)
- Gustavo Caballero-Flores
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI, USA.
| | - Joseph M Pickard
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI, USA
| | - Gabriel Núñez
- Department of Pathology and Rogel Cancer Center, The University of Michigan Medical School, Ann Arbor, MI, USA.
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Williamson CHD, Roe CC, Terriquez J, Hornstra H, Lucero S, Nunnally AE, Vazquez AJ, Vinocur J, Plude C, Nienstadt L, Stone NE, Celona KR, Wagner DM, Keim P, Sahl JW. A local-scale One Health genomic surveillance of Clostridioides difficile demonstrates highly related strains from humans, canines, and the environment. Microb Genom 2023; 9. [PMID: 37347682 DOI: 10.1099/mgen.0.001046] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2023] Open
Abstract
Although infections caused by Clostridioides difficile have historically been attributed to hospital acquisition, growing evidence supports the role of community acquisition in C. difficile infection (CDI). Symptoms of CDI can range from mild, self-resolving diarrhoea to toxic megacolon, pseudomembranous colitis, and death. In this study, we sampled C. difficile from clinical, environmental, and canine reservoirs in Flagstaff, Arizona, USA, to understand the distribution and transmission of the pathogen in a One Health framework; Flagstaff is a medium-sized, geographically isolated city with a single hospital system, making it an ideal site to characterize genomic overlap between sequenced C. difficile isolates across reservoirs. An analysis of 562 genomes from Flagstaff isolates identified 65 sequence types (STs), with eight STs being found across all three reservoirs and another nine found across two reservoirs. A screen of toxin genes in the pathogenicity locus identified nine STs where all isolates lost the toxin genes needed for CDI manifestation (tcdB, tcdA), demonstrating the widespread distribution of non-toxigenic C. difficile (NTCD) isolates in all three reservoirs; 15 NTCD genomes were sequenced from symptomatic, clinical samples, including two from mixed infections that contained both tcdB+ and tcdB- isolates. A comparative single nucleotide polymorphism (SNP) analysis of clinically derived isolates identified 78 genomes falling within clusters separated by ≤2 SNPs, indicating that ~19 % of clinical isolates are associated with potential healthcare-associated transmission clusters; only symptomatic cases were sampled in this study, and we did not sample asymptomatic transmission. Using this same SNP threshold, we identified genomic overlap between canine and soil isolates, as well as putative transmission between environmental and human reservoirs. The core genome of isolates sequenced in this study plus a representative set of public C. difficile genomes (n=136), was 2690 coding region sequences, which constitutes ~70 % of an individual C. difficile genome; this number is significantly higher than has been published in some other studies, suggesting that genome data quality is important in understanding the minimal number of genes needed by C. difficile. This study demonstrates the close genomic overlap among isolates sampled across reservoirs, which was facilitated by maximizing the genomic search space used for comprehensive identification of potential transmission events. Understanding the distribution of toxigenic and non-toxigenic C. difficile across reservoirs has implications for surveillance sampling strategies, characterizing routes of infections, and implementing mitigation measures to limit human infection.
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Affiliation(s)
| | - Chandler C Roe
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | | | - Heidie Hornstra
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Samantha Lucero
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Amalee E Nunnally
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Adam J Vazquez
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | | | | | | | - Nathan E Stone
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Kimberly R Celona
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - David M Wagner
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Paul Keim
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
| | - Jason W Sahl
- The Pathogen and Microbiome Institute, Northern Arizona University, Flagstaff, AZ, USA
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9
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Dong Q, Lin H, Allen MM, Garneau JR, Sia JK, Smith RC, Haro F, McMillen T, Pope RL, Metcalfe C, Burgo V, Woodson C, Dylla N, Kohout C, Sundararajan A, Snitkin ES, Young VB, Fortier LC, Kamboj M, Pamer EG. Virulence and genomic diversity among clinical isolates of ST1 (BI/NAP1/027) Clostridioides difficile. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.12.523823. [PMID: 36711955 PMCID: PMC9882218 DOI: 10.1101/2023.01.12.523823] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Clostridioides difficile (C. difficile) , a leading cause of nosocomial infection, produces toxins that damage the colonic epithelium and results in colitis that varies from mild to fulminant. Variation in disease severity is poorly understood and has been attributed to host factors (age, immune competence and intestinal microbiome composition) and/or virulence differences between C. difficile strains, with some, such as the epidemic BI/NAP1/027 (MLST1) strain, being associated with greater virulence. We tested 23 MLST1(ST1) C. difficile clinical isolates for virulence in antibiotic-treated C57BL/6 mice. All isolates encoded a complete Tcd pathogenicity locus and achieved similar colonization densities in mice. Disease severity varied, however, with 5 isolates causing lethal infections, 16 isolates causing a range of moderate infections and 2 isolates resulting in no detectable disease. The avirulent ST1 isolates did not cause disease in highly susceptible Myd88 -/- or germ-free mice. Genomic analysis of the avirulent isolates revealed a 69 base-pair deletion in the N-terminus of the cdtR gene, which encodes a response regulator for binary toxin (CDT) expression. Genetic deletion of the 69 base-pair cdtR sequence in the highly virulent ST1 R20291 C. difficile strain rendered it avirulent and reduced toxin gene transcription in cecal contents. Our study demonstrates that a natural deletion within cdtR attenuates virulence in the epidemic ST1 C. difficile strain without reducing colonization and persistence in the gut. Distinguishing strains on the basis of cdtR may enhance the specificity of diagnostic tests for C. difficile colitis.
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Affiliation(s)
- Qiwen Dong
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Huaiying Lin
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Marie-Maude Allen
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Julian R. Garneau
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jonathan K. Sia
- Immunology Program, Memorial Sloan Kettering Cancer Center, New York City, New York, USA
| | - Rita C. Smith
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Fidel Haro
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Tracy McMillen
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Rosemary L. Pope
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
- Committee on Immunology, University of Chicago, Chicago, Illinois, USA
| | - Carolyn Metcalfe
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Victoria Burgo
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Che Woodson
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Nicholas Dylla
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | - Claire Kohout
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
| | | | - Evan S Snitkin
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Vincent B. Young
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology & Immunology, University of Michigan, Ann Arbor, MI, USA
| | - Louis-Charles Fortier
- Department of Microbiology and Infectious Diseases, Universite de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Mini Kamboj
- Infection Control, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York, USA
| | - Eric G. Pamer
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Duchossois Family Institute, University of Chicago, Chicago, Illinois, USA
- Committee on Immunology, University of Chicago, Chicago, Illinois, USA
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10
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Mileto SJ, Hutton ML, Walton SL, Das A, Ioannidis LJ, Ketagoda D, Quinn KM, Denton KM, Hansen DS, Lyras D. Bezlotoxumab prevents extraintestinal organ damage induced by Clostridioides difficile infection. Gut Microbes 2022; 14:2117504. [PMID: 36045589 PMCID: PMC9450906 DOI: 10.1080/19490976.2022.2117504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Clostridioides difficile is the most common cause of infectious antibiotic-associated diarrhea, with disease mediated by two major toxins TcdA and TcdB. In severe cases, systemic disease complications may arise, resulting in fatal disease. Systemic disease in animal models has been described, with thymic damage an observable consequence of severe disease in mice. Using a mouse model of C. difficile infection, we examined this disease phenotype, focussing on the thymus and serum markers of systemic disease. The efficacy of bezlotoxumab, a monoclonal TcdB therapeutic, to prevent toxin mediated systemic disease complications was also examined. C. difficile infection causes toxin-dependent thymic damage and CD4+CD8+ thymocyte depletion in mice. These systemic complications coincide with changes in biochemical markers of liver and kidney function, including increased serum urea and creatinine, and hypoglycemia. Administration of bezlotoxumab during C. difficile infection prevents systemic disease and thymic atrophy, without blocking gut damage, suggesting the leakage of gut contents into circulation may influence systemic disease. As the thymus has such a crucial role in T cell production and immune system development, these findings may have important implications in relapse of C. difficile disease and impaired immunity during C. difficile infection. The prevention of thymic atrophy and reduced systemic response following bezlotoxumab treatment, without altering colonic damage, highlights the importance of systemic disease in C. difficile infection, and provides new insights into the mechanism of action for this therapeutic.Abbreviations: Acute kidney injury (AKI); Alanine Transaminase (ALT); Aspartate Aminotransferase (AST); C. difficile infection (CDI); chronic kidney disease (CKD); combined repetitive oligo-peptides (CROPS); cardiovascular disease (CVD); Double positive (DP); hematoxylin and eosin (H&E); immunohistochemical (IHC); multiple organ dysfunction syndrome (MODS); phosphate buffered saline (PBS); standard error of the mean (SEM); surface layer proteins (SLP); Single positive (SP); wild-type (WT).
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Affiliation(s)
- Steven J. Mileto
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Melanie L. Hutton
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Sarah L. Walton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Antariksh Das
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Lisa J. Ioannidis
- Walter and Eliza Hall Insitiute, Infectious Diseases and Immune Defence Division, Parkville, Australia,Department of Medical Biology, the University of Melbourne, Parkville, Australia
| | - Don Ketagoda
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia
| | - Kylie M. Quinn
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia,RMIT University School of Biomedical and Health Sciences, Chronic Inflammatory and Infectious Diseases Program, Bundoora, Australia
| | - Kate M. Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Diana S. Hansen
- Walter and Eliza Hall Insitiute, Infectious Diseases and Immune Defence Division, Parkville, Australia,Department of Medical Biology, the University of Melbourne, Parkville, Australia
| | - Dena Lyras
- Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, Clayton, Australia,CONTACT Dena Lyras Infection and Immunity Program, Monash Biomedicine Discovery Institute and Department of Microbiology, Monash University, 19 Innovation Walk, Clayton, Victoria3800, Australia
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11
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Development of a Dual-Fluorescent-Reporter System in Clostridioides difficile Reveals a Division of Labor between Virulence and Transmission Gene Expression. mSphere 2022; 7:e0013222. [PMID: 35638354 PMCID: PMC9241537 DOI: 10.1128/msphere.00132-22] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The bacterial pathogen Clostridioides difficile causes gastroenteritis by producing toxins and transmits disease by making resistant spores. Toxin and spore production are energy-expensive processes that are regulated by multiple transcription factors in response to many environmental inputs. While toxin and sporulation genes are both induced in only a subset of C. difficile cells, the relationship between these two subpopulations remains unclear. To address whether C. difficile coordinates the generation of these subpopulations, we developed a dual-transcriptional-reporter system that allows toxin and sporulation gene expression to be simultaneously visualized at the single-cell level using chromosomally encoded mScarlet and mNeonGreen fluorescent transcriptional reporters. We then adapted an automated image analysis pipeline to quantify toxin and sporulation gene expression in thousands of individual cells under different medium conditions and in different genetic backgrounds. These analyses revealed that toxin and sporulation gene expression rarely overlap during growth on agar plates, whereas broth culture increases this overlap. Our results suggest that certain growth conditions promote a “division of labor” between transmission and virulence gene expression, highlighting how environmental inputs influence these subpopulations. Our data further suggest that the RstA transcriptional regulator skews the population to activate sporulation genes rather than toxin genes. Given that recent work has revealed population-wide heterogeneity for numerous cellular processes in C. difficile, we anticipate that our dual-reporter system will be broadly useful for determining the overlap between these subpopulations. IMPORTANCEClostridioides difficile is an important nosocomial pathogen that causes severe diarrhea by producing toxins and transmits disease by producing spores. While both processes are crucial for C. difficile disease, only a subset of cells express toxins and/or undergo sporulation. Whether C. difficile coordinates the subset of cells inducing these energy-expensive processes remains unknown. To address this question, we developed a dual-fluorescent-reporter system coupled with an automated image analysis pipeline to rapidly compare the expression of two genes of interest across thousands of cells. Using this system, we discovered that certain growth conditions, particularly growth on agar plates, induce a “division of labor” between toxin and sporulation gene expression. Since C. difficile exhibits phenotypic heterogeneity for numerous vital cellular processes, this novel dual-reporter system will enable future studies aimed at understanding how C. difficile coordinates various subpopulations throughout its infectious disease cycle.
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12
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Systems biology approach to functionally assess the Clostridioides difficile pangenome reveals genetic diversity with discriminatory power. Proc Natl Acad Sci U S A 2022; 119:e2119396119. [PMID: 35476524 PMCID: PMC9170149 DOI: 10.1073/pnas.2119396119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SignificanceClostridioides difficile infections are the most common source of hospital-acquired infections and are responsible for an extensive burden on the health care system. Strains of the C. difficile species comprise diverse lineages and demonstrate genome variability, with advantageous trait acquisition driving the emergence of endemic lineages. Here, we present a systems biology analysis of C. difficile that evaluates strain-specific genotypes and phenotypes to investigate the overall diversity of the species. We develop a strain typing method based on similarity of accessory genomes to identify and contextualize genetic loci capable of discriminating between strain groups.
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13
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An aniline-substituted bile salt analog protects both mice and hamsters from multiple Clostridioides difficile strains. Antimicrob Agents Chemother 2021; 66:e0143521. [PMID: 34780262 DOI: 10.1128/aac.01435-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clostridioides difficile infection (CDI) is the major identifiable cause of antibiotic-associated diarrhea. The emergence of hypervirulent C. difficile strains has led to increases in both hospital- and community-acquired CDI. Furthermore, CDI relapse from hypervirulent strains can reach up to 25%. Thus, standard treatments are rendered less effective, making new methods of prevention and treatment more critical. Previously, the bile salt analog CamSA was shown to inhibit spore germination in vitro and protect mice and hamsters from C. difficile strain 630. Here, we show that CamSA was less active at preventing spore germination of other C. difficile ribotypes, including the hypervirulent strain R20291. Strain-specific in vitro germination activity of CamSA correlated with its ability to prevent CDI in mice. Additional bile salt analogs were screened for in vitro germination inhibition activity against strain R20291, and the most active compounds were tested against other strains. An aniline-substituted bile salt analog, (CaPA), was found to be a better anti-germinant than CamSA against eight different C. difficile strains. In addition, CaPA was capable of reducing, delaying, or preventing murine CDI signs in all strains tested. CaPA-treated mice showed no obvious toxicity and showed minor effects on their gut microbiome. CaPA's efficacy was further confirmed by its ability to prevent CDI in hamsters infected with strain 630. These data suggest that C. difficile spores respond to germination inhibitors in a strain-dependent manner. However, careful screening can identify anti-germinants with broad CDI prophylaxis activity.
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14
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Ressler A, Wang J, Rao K. Defining the black box: a narrative review of factors associated with adverse outcomes from severe Clostridioides difficile infection. Therap Adv Gastroenterol 2021; 14:17562848211048127. [PMID: 34646358 PMCID: PMC8504270 DOI: 10.1177/17562848211048127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/31/2021] [Indexed: 02/04/2023] Open
Abstract
In the United States, Clostridioides difficile infection (CDI) is the leading cause of healthcare-associated infection, affecting nearly half a million people and resulting in more than 20,000 in-hospital deaths every year. It is therefore imperative to better characterize the intricate interplay between C. difficile microbial factors, host immunologic signatures, and clinical features that are associated with adverse outcomes of severe CDI. In this narrative review, we discuss the implications of C. difficile genetics and virulence factors in the molecular epidemiology of CDI, and the utility of early biomarkers in predicting the clinical trajectory of patients at risk of developing severe CDI. Furthermore, we identify associations between host immune factors and CDI outcomes in both animal models and human studies. Next, we highlight clinical factors including renal dysfunction, aging, blood biomarkers, level of care, and chronic illnesses that can affect severe CDI diagnosis and outcome. Finally, we present our perspectives on two specific treatments pertinent to patient outcomes: metronidazole administration and surgery. Together, this review explores the various venues of CDI research and highlights the importance of integrating microbial, host, and clinical data to help clinicians make optimal treatment decisions based on accurate prediction of disease progression.
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Affiliation(s)
- Adam Ressler
- Division of Infectious Diseases, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Joyce Wang
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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15
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Ahn SW, Lee SH, Kim UJ, Jang HC, Choi HJ, Choy HE, Kang SJ, Roh SW. Genomic characterization of nine Clostridioides difficile strains isolated from Korean patients with Clostridioides difficile infection. Gut Pathog 2021; 13:55. [PMID: 34530913 PMCID: PMC8447795 DOI: 10.1186/s13099-021-00451-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/08/2021] [Indexed: 12/14/2022] Open
Abstract
Background Clostridioides difficile infection (CDI) is an infectious nosocomial disease caused by Clostridioides difficile, an opportunistic pathogen that occurs in the intestine after extensive antibiotic regimens. Results Nine C. difficile strains (CBA7201–CBA7209) were isolated from nine patients diagnosed with CDI at the national university hospital in Korea, and the whole genomes of these strains were sequenced to identify their genomic characteristics. Comparative genomic analysis was performed using 51 reference strains and the nine isolated herein. Phylogenetic analysis based on 16S rRNA gene sequences confirmed that all 60 C. difficile strains belong to the genus Clostridioides, while core-genome tree indicated that they were divided into five groups, which was consistent with the results of MLST clade analysis. All strains were confirmed to have a clindamycin antibiotic resistance gene, but the other antibiotic resistance genes differ depending on the MLST clade. Interestingly, the six strains belonging to the sequence type 17 among the nine C. difficile strains isolated here exhibited unique genomic characteristics for PaLoc and CdtLoc, the two toxin gene loci identified in this study, and harbored similar antibiotic resistance genes. Conclusion In this study, we identified the specific genomic characteristics of Korean C. difficile strains, which could serve as basic information for CDI prevention and treatment in Korea. Supplementary Information The online version contains supplementary material available at 10.1186/s13099-021-00451-3.
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Affiliation(s)
- Seung Woo Ahn
- Microbiology and Functionality Research Group, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, 61755, Gwangju, Republic of Korea
| | - Se Hee Lee
- Microbiology and Functionality Research Group, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, 61755, Gwangju, Republic of Korea
| | - Uh Jin Kim
- Department of Infectious Diseases, Chonnam National University Hospital, 61469, Gwangju, Republic of Korea
| | - Hee-Chang Jang
- Department of Infectious Diseases, Chonnam National University Hospital, 61469, Gwangju, Republic of Korea
| | - Hak-Jong Choi
- Microbiology and Functionality Research Group, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, 61755, Gwangju, Republic of Korea
| | - Hyon E Choy
- Department of Microbiology, Chonnam National University Medical School, 61469, Gwangju, Republic of Korea
| | - Seung Ji Kang
- Department of Infectious Diseases, Chonnam National University Hospital, 61469, Gwangju, Republic of Korea.
| | - Seong Woon Roh
- Microbiology and Functionality Research Group, World Institute of Kimchi, 86, Kimchi-ro, Nam-gu, 61755, Gwangju, Republic of Korea.
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16
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Chiu PJ, Rathod J, Hong YP, Tsai PJ, Hung YP, Ko WC, Chen JW, Paredes-Sabja D, Huang IH. Clostridioides difficile spores stimulate inflammatory cytokine responses and induce cytotoxicity in macrophages. Anaerobe 2021; 70:102381. [PMID: 34082120 DOI: 10.1016/j.anaerobe.2021.102381] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 03/30/2021] [Accepted: 05/04/2021] [Indexed: 02/08/2023]
Abstract
Clostridioides difficile is a gram-positive, spore-forming anaerobic bacterium, and the leading cause of antibiotic-associated diarrhea worldwide. During C. difficile infection, spores germinate in the presence of bile acids into vegetative cells that subsequently colonize the large intestine and produce toxins. In this study, we demonstrated that C. difficile spores can universally adhere to, and be phagocytosed by, murine macrophages. Only spores from toxigenic strains were able to significantly stimulate the production of inflammatory cytokines by macrophages and subsequently induce significant cytotoxicity. Spores from the isogenic TcdA and TcdB double mutant induced significantly lower inflammatory cytokines and cytotoxicity in macrophages, and these activities were restored by pre-exposure of the spores to either toxins. These findings suggest that during sporulation, spores might be coated with C. difficile toxins from the environment, which could affect C. difficile pathogenesis in vivo.
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Affiliation(s)
- Po-Jung Chiu
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jagat Rathod
- Department of Earth Sciences National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ping Hong
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Jane Tsai
- Department of Medical Laboratory Science and Biotechnology, National Cheng Kung University, Tainan, Taiwan; Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Yuan-Pin Hung
- Department of Internal Medicine, Tainan Hospital, Ministry of Health and Welfare, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Jenn-Wei Chen
- Department of Microbiology and Immunology, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Daniel Paredes-Sabja
- Department of Biology, Texas A&M University, College Station, TX, 77843, USA; Millennium Nucleus in the Biology of Intestinal Microbiota, Santiago, Chile
| | - I-Hsiu Huang
- Department of Biochemistry and Microbiology, Oklahoma State University Center for Health Sciences, Tulsa, OK, USA; Oklahoma State University College of Osteopathic Medicine at Cherokee Nation, Tahlequah, OK, USA.
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17
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Lan P, Shi Q, Zhang P, Chen Y, Yan R, Hua X, Jiang Y, Zhou J, Yu Y. Core Genome Allelic Profiles of Clinical Klebsiella pneumoniae Strains Using a Random Forest Algorithm Based on Multilocus Sequence Typing Scheme for Hypervirulence Analysis. J Infect Dis 2021; 221:S263-S271. [PMID: 32176785 DOI: 10.1093/infdis/jiz562] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND Hypervirulent Klebsiella pneumoniae (hvKP) infections can have high morbidity and mortality rates owing to their invasiveness and virulence. However, there are no effective tools or biomarkers to discriminate between hvKP and nonhypervirulent K. pneumoniae (nhvKP) strains. We aimed to use a random forest algorithm to predict hvKP based on core-genome data. METHODS In total, 272 K. pneumoniae strains were collected from 20 tertiary hospitals in China and divided into hvKP and nhvKP groups according to clinical criteria. Clinical data comparisons, whole-genome sequencing, virulence profile analysis, and core genome multilocus sequence typing (cgMLST) were performed. We then established a random forest predictive model based on the cgMLST scheme to prospectively identify hvKP. The random forest is an ensemble learning method that generates multiple decision trees during the training process and each decision tree will output its own prediction results corresponding to the input. The predictive ability of the model was assessed by means of area under the receiver operating characteristic curve. RESULTS Patients in the hvKP group were younger than those in the nhvKP group (median age, 58.0 and 68.0 years, respectively; P < .001). More patients in the hvKP group had underlying diabetes mellitus (43.1% vs 20.1%; P < .001). Clinically, carbapenem-resistant K. pneumoniae was less common in the hvKP group (4.1% vs 63.8%; P < .001), whereas the K1/K2 serotype, sequence type (ST) 23, and positive string tests were significantly higher in the hvKP group. A cgMLST-based minimal spanning tree revealed that hvKP strains were scattered sporadically within nhvKP clusters. ST23 showed greater genome diversification than did ST11, according to cgMLST-based allelic differences. Primary virulence factors (rmpA, iucA, positive string test result, and the presence of virulence plasmid pLVPK) were poor predictors of the hypervirulence phenotype. The random forest model based on the core genome allelic profile presented excellent predictive power, both in the training and validating sets (area under receiver operating characteristic curve, 0.987 and 0.999 in the training and validating sets, respectively). CONCLUSIONS A random forest algorithm predictive model based on the core genome allelic profiles of K. pneumoniae was accurate to identify the hypervirulent isolates.
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Affiliation(s)
- Peng Lan
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.,Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiucheng Shi
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Ping Zhang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yan Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Rushuang Yan
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.,Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Yan Jiang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
| | - Jiancang Zhou
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China.,Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, China
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18
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McLean K, Balada-Llasat JM, Waalkes A, Pancholi P, Salipante SJ. Whole-genome sequencing of clinical Clostridioides difficile isolates reveals molecular epidemiology and discrepancies with conventional laboratory diagnostic testing. J Hosp Infect 2020; 108:64-71. [PMID: 33227298 DOI: 10.1016/j.jhin.2020.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 10/06/2020] [Accepted: 11/16/2020] [Indexed: 12/29/2022]
Abstract
BACKGROUND The high clinical burden of Clostridioides difficile infections merits rapid and sensitive identification of affected individuals. However, effective diagnosis remains challenging. Current best practice guidelines recommend molecular and/or direct toxin detection-based screening for symptomatic individuals, but previous work has called into question the concordance and performance of extant clinical assays. AIM To better correlate the genomic and phenotypic properties of clinical C. difficile isolates with laboratory testing outcomes in both C. difficile-infected patients and asymptomatic carriers. METHODS Whole-genome sequencing of clinical C. difficile isolates collected from an inpatient population at a single healthcare institution was performed, enabling examination of their molecular epidemiology and toxigenic gene content. Genomic findings were compared with clinical testing outcomes, identifying multiple diagnostic discrepancies. FINDINGS Toxigenic culture, considered a 'reference standard', provided perfect sensitivity and specificity in predicting toxigenic gene content, whereas reduced performance was observed for Simplexa C. difficile Direct Assay (100% specificity, 88% sensitivity), Gene Xpert CD/Epi Assay (86% specificity, 83% sensitivity), and Quick Check Complete Tox A/B (100% specificity, 30% sensitivity). Genomic analysis additionally revealed variability in toxin gene sequences among C. difficile strains, phylogenomic equivalency between isolates from affected patients and carriers, and patient carriage with uncommon environmentally derived C. difficile lineages, as well as presenting opportunities for tracing pathogen transmission events. CONCLUSION These results highlight the variable performance of clinical stool-based testing approaches as well as the potential diagnostic utility of whole-genome sequencing as an alternative to conventional testing algorithms.
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Affiliation(s)
- K McLean
- University of Washington Department of Laboratory Medicine, Seattle, WA, USA
| | - J-M Balada-Llasat
- Ohio State University Wexner Medical Center, Department of Pathology, Columbus, OH, USA
| | - A Waalkes
- University of Washington Department of Laboratory Medicine, Seattle, WA, USA
| | - P Pancholi
- Ohio State University Wexner Medical Center, Department of Pathology, Columbus, OH, USA.
| | - S J Salipante
- University of Washington Department of Laboratory Medicine, Seattle, WA, USA.
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19
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Quantitative characterization of Clostridioides difficile population in the gut microbiome of patients with C. difficile infection and their association with clinical factors. Sci Rep 2020; 10:17608. [PMID: 33077744 PMCID: PMC7573688 DOI: 10.1038/s41598-020-74090-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022] Open
Abstract
Objective was to analyse bacterial composition and abundance of Clostridioides difficile in gut microbiome of patients with C. difficile infection (CDI) in association with clinical characteristics. Whole metagenome sequencing of gut microbiome of 26 CDI patients was performed, and the relative abundance of C. difficile and its toxin genes was measured. Clinical characteristics of the patients were obtained through medical records. A strong correlation between the abundance of C. difficile and tcdB genes in CDI patients was found. The relative abundance of C. difficile in the gut microbiome ranged from undetectable to 2.8% (median 0.089). Patients with fever exhibited low abundance of C. difficile in their gut, and patients with fewer C. difficile organisms required long-term anti-CDI treatment. Abundance of Bifidobacterium and Bacteroides negatively correlated with that of C. difficile at the genus level. CDI patients were clustered using the bacterial composition of the gut: one with high population of Enterococcus (cluster 1, n = 12) and another of Bacteroides or Lactobacillus (cluster 2, n = 14). Cluster1 showed significantly lower bacterial diversity and clinical cure at the end of treatment. Additionally, patients with CDI exhibited increased ARGs; notably, blaTEM, blaSHV and blaCTX-M were enriched. C. difficile existed in variable proportion of the gut microbiome in CDI patients. CDI patients with Enterococcus-rich microbiome in the gut had lower bacterial diversity and poorer clinical cure.
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20
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Saldanha GZ, Pires RN, Rauber AP, de Lima-Morales D, Falci DR, Caierão J, Pasqualotto AC, Martins AF. Genetic relatedness, Virulence factors and Antimicrobial Resistance of C. difficile strains from hospitalized patients in a multicentric study in Brazil. J Glob Antimicrob Resist 2020; 22:117-121. [DOI: 10.1016/j.jgar.2020.01.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/07/2020] [Accepted: 01/09/2020] [Indexed: 02/07/2023] Open
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21
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Bushman FD, Conrad M, Ren Y, Zhao C, Gu C, Petucci C, Kim MS, Abbas A, Downes KJ, Devas N, Mattei LM, Breton J, Kelsen J, Marakos S, Galgano A, Kachelries K, Erlichman J, Hart JL, Moraskie M, Kim D, Zhang H, Hofstaedter CE, Wu GD, Lewis JD, Zackular JP, Li H, Bittinger K, Baldassano R. Multi-omic Analysis of the Interaction between Clostridioides difficile Infection and Pediatric Inflammatory Bowel Disease. Cell Host Microbe 2020; 28:422-433.e7. [PMID: 32822584 DOI: 10.1016/j.chom.2020.07.020] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 06/09/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022]
Abstract
Children with inflammatory bowel diseases (IBD) are particularly vulnerable to infection with Clostridioides difficile (CDI). IBD and IBD + CDI have overlapping symptoms but respond to distinctive treatments, highlighting the need for diagnostic biomarkers. Here, we studied pediatric patients with IBD and IBD + CDI, comparing longitudinal data on the gut microbiome, metabolome, and other measures. The microbiome is dysbiotic and heterogeneous in both disease states, but the metabolome reveals disease-specific patterns. The IBD group shows increased concentrations of markers of inflammation and tissue damage compared with healthy controls, and metabolic changes associate with susceptibility to CDI. In IBD + CDI, we detect both metabolites associated with inflammation/tissue damage and fermentation products produced by C. difficile. The most discriminating metabolite found is isocaproyltaurine, a covalent conjugate of a distinctive C. difficile fermentation product (isocaproate) and an amino acid associated with tissue damage (taurine), which may be useful as a joint marker of the two disease processes.
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Affiliation(s)
- Frederic D Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Maire Conrad
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Yue Ren
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Chunyu Zhao
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Christopher Gu
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christopher Petucci
- Metabolomics Core, Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Min-Soo Kim
- Metabolomics Core, Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Arwa Abbas
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kevin J Downes
- Division of Infectious Diseases, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Nina Devas
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Lisa M Mattei
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jessica Breton
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Judith Kelsen
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Sarah Marakos
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Alissa Galgano
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Kelly Kachelries
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jessi Erlichman
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jessica L Hart
- Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Michael Moraskie
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Dorothy Kim
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Huanjia Zhang
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Casey E Hofstaedter
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Gary D Wu
- Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James D Lewis
- Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Joseph P Zackular
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Hongzhe Li
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kyle Bittinger
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Robert Baldassano
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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22
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Kc R, Leong KWC, Harkness NM, Lachowicz J, Gautam SS, Cooley LA, McEwan B, Petrovski S, Karupiah G, O'Toole RF. Whole-genome analyses reveal gene content differences between nontypeable Haemophilus influenzae isolates from chronic obstructive pulmonary disease compared to other clinical phenotypes. Microb Genom 2020; 6. [PMID: 32706329 PMCID: PMC7641420 DOI: 10.1099/mgen.0.000405] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) colonizes human upper respiratory airways and plays a key role in the course and pathogenesis of acute exacerbations of chronic obstructive pulmonary disease (COPD). Currently, it is not possible to distinguish COPD isolates of NTHi from other clinical isolates of NTHi using conventional genotyping methods. Here, we analysed the core and accessory genome of 568 NTHi isolates, including 40 newly sequenced isolates, to look for genetic distinctions between NTHi isolates from COPD with respect to other illnesses, including otitis media, meningitis and pneumonia. Phylogenies based on polymorphic sites in the core-genome did not show discrimination between NTHi strains collected from different clinical phenotypes. However, pan-genome-wide association studies identified 79 unique NTHi accessory genes that were significantly associated with COPD. Furthermore, many of the COPD-related NTHi genes have known or predicted roles in virulence, transmembrane transport of metal ions and nutrients, cellular respiration and maintenance of redox homeostasis. This indicates that specific genes may be required by NTHi for its survival or virulence in the COPD lung. These results advance our understanding of the pathogenesis of NTHi infection in COPD lungs.
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Affiliation(s)
- Rajendra Kc
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| | - Kelvin W C Leong
- Department of Pharmacy and Biomedical Sciences, School of Molecular Sciences, College of Science, Health and Engineering, La Trobe University, Victoria, Australia
| | - Nicholas M Harkness
- Department of Respiratory and Sleep Medicine, Royal Hobart Hospital, Tasmania, Australia
| | - Julia Lachowicz
- Department of Respiratory and Sleep Medicine, Royal Hobart Hospital, Tasmania, Australia
| | - Sanjay S Gautam
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| | - Louise A Cooley
- Department of Microbiology and Infectious Diseases, Royal Hobart Hospital, Tasmania, Australia
| | - Belinda McEwan
- Department of Microbiology and Infectious Diseases, Royal Hobart Hospital, Tasmania, Australia
| | - Steve Petrovski
- Department of Physiology, Anatomy and Microbiology, School of Life Sciences, La Trobe University, Victoria, Australia
| | - Gunasegaran Karupiah
- Tasmanian School of Medicine, College of Health and Medicine, University of Tasmania, Tasmania, Australia
| | - Ronan F O'Toole
- Department of Pharmacy and Biomedical Sciences, School of Molecular Sciences, College of Science, Health and Engineering, La Trobe University, Victoria, Australia
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23
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Wang LYR, Jokinen CC, Laing CR, Johnson RP, Ziebell K, Gannon VPJ. Assessing the genomic relatedness and evolutionary rates of persistent verotoxigenic Escherichia coli serotypes within a closed beef herd in Canada. Microb Genom 2020; 6. [PMID: 32496181 PMCID: PMC7371104 DOI: 10.1099/mgen.0.000376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Verotoxigenic Escherichia coli (VTEC) are food- and water-borne pathogens associated with both sporadic illness and outbreaks of enteric disease. While it is known that cattle are reservoirs of VTEC, little is known about the genomic variation of VTEC in cattle, and whether the variation in genomes reported for human outbreak strains is consistent with individual animal or group/herd sources of infection. A previous study of VTEC prevalence identified serotypes carried persistently by three consecutive cohorts of heifers within a closed herd of cattle. This present study aimed to: (i) determine whether the genomic relatedness of bovine isolates is similar to that reported for human strains associated with single source outbreaks, (ii) estimate the rates of genome change among dominant serotypes over time within a cattle herd, and (iii) identify genomic features of serotypes associated with persistence in cattle. Illumina MiSeq genome sequencing and genotyping based on allelic and single nucleotide variations were completed, while genome change over time was measured using Bayesian evolutionary analysis sampling trees. The accessory genome, including the non-protein-encoding intergenic regions (IGRs), virulence factors, antimicrobial-resistance genes and plasmid gene content of representative persistent and sporadic cattle strains were compared using Fisher’s exact test corrected for multiple comparisons. Herd strains from serotypes O6:H34 (n=22), O22:H8 (n=30), O108:H8 (n=39), O139:H19 (n=44) and O157:H7 (n=106) were readily distinguishable from epidemiologically unrelated strains of the same serotype using a similarity threshold of 10 or fewer allele differences between adjacent nodes. Temporal-cohort clustering within each serotype was supported by date randomization analysis. Substitutions per site per year were consistent with previously reported values for E. coli; however, there was low branch support for these values. Acquisition of the phage-encoded Shiga toxin 2 gene in serotype O22:H8 was observed. Pan-genome analyses identified accessory regions that were more prevalent in persistent serotypes (P≤0.05) than in sporadic serotypes. These results suggest that VTEC serotypes from a specific cattle population are highly clonal with a similar level of relatedness as human single-source outbreak-associated strains, but changes in the genome occur gradually over time. Additionally, elements in the accessory genomes may provide a selective advantage for persistence of VTEC within cattle herds.
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Affiliation(s)
- Lu Ya Ruth Wang
- National Microbiology Laboratory, Public Health Agency of Canada, Lethbridge, Alberta, Canada
| | | | - Chad R Laing
- National Centre for Animal Disease, Canadian Food Inspection Agency, Lethbridge, Alberta, Canada
| | - Roger P Johnson
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Kim Ziebell
- National Microbiology Laboratory, Public Health Agency of Canada, Guelph, Ontario, Canada
| | - Victor P J Gannon
- National Microbiology Laboratory, Public Health Agency of Canada, Lethbridge, Alberta, Canada
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24
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Sorbara MT, Littmann ER, Fontana E, Moody TU, Kohout CE, Gjonbalaj M, Eaton V, Seok R, Leiner IM, Pamer EG. Functional and Genomic Variation between Human-Derived Isolates of Lachnospiraceae Reveals Inter- and Intra-Species Diversity. Cell Host Microbe 2020; 28:134-146.e4. [PMID: 32492369 DOI: 10.1016/j.chom.2020.05.005] [Citation(s) in RCA: 193] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/11/2020] [Accepted: 05/06/2020] [Indexed: 02/03/2023]
Abstract
Bacteria belonging to the Lachnospiraceae family are abundant, obligate anaerobic members of the microbiota in healthy humans. Lachnospiraceae impact their hosts by producing short-chain fatty acids, converting primary to secondary bile acids, and facilitating colonization resistance against intestinal pathogens. To increase our understanding of genomic and functional diversity between members of this family, we cultured 273 Lachnospiraceae isolates representing 11 genera and 27 species from human donors and performed whole-genome sequencing assembly and annotation. This analysis revealed substantial inter- and intra-species diversity in pathways that likely influence an isolate's ability to impact host health. These differences are likely to impact colonization resistance through lantibiotic expression or intestinal acidification, influence host mucosal immune cells and enterocytes via butyrate production, or contribute to synergism within a consortium by heterogenous polysaccharide metabolism. Identification of these specific functions could facilitate development of probiotic bacterial consortia that drive and/or restore in vivo microbiome functions.
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Affiliation(s)
- Matthew T Sorbara
- Duchossois Family Institute, The University of Chicago, Chicago, IL 60637, USA; Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA; Department of Medicine, Section of Infectious Diseases and Global Health, The University of Chicago, Chicago, IL 60637, USA.
| | - Eric R Littmann
- Duchossois Family Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Emily Fontana
- Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Thomas U Moody
- Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Claire E Kohout
- Duchossois Family Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Mergim Gjonbalaj
- Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Vincent Eaton
- Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ruth Seok
- Center for Microbes, Inflammation and Cancer, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Ingrid M Leiner
- Duchossois Family Institute, The University of Chicago, Chicago, IL 60637, USA
| | - Eric G Pamer
- Duchossois Family Institute, The University of Chicago, Chicago, IL 60637, USA; Department of Microbiology, The University of Chicago, Chicago, IL 60637, USA; Department of Medicine, Section of Infectious Diseases and Global Health, The University of Chicago, Chicago, IL 60637, USA.
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25
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Ma KGL, Lertpiriyapong K, Piersigilli A, Dobtsis I, Wipf JRK, Littmann ER, Leiner I, Pamer EG, Ricart Arbona RJ, Lipman NS. Outbreaks of Typhlocolitis Caused by Hypervirulent Group ST1 Clostridioides difficile in Highly Immunocompromised Strains of Mice. Comp Med 2020; 70:277-290. [PMID: 32404234 PMCID: PMC7287380 DOI: 10.30802/aalas-cm-19-000109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 12/15/2019] [Accepted: 01/13/2020] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile is an enteric pathogen that can cause significant clinical disease in both humans and animals. However, clinical disease arises most commonly after treatment with broad-spectrum antibiotics. The organism's ability to cause naturally occurring disease in mice is rare, and little is known about its clinical significance in highly immunocompromised mice. We report on 2 outbreaks of diarrhea associated with C. difficile in mice. In outbreak 1, 182 of approximately 2, 400 NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) and related strains of mice became clinically ill after cessation of a 14-d course of 0.12% amoxicillin feed to control an increase in clinical signs associated with Corynebacterium bovis infection. Most mice had been engrafted with human tumors; the remainder were experimentally naïve. Affected animals exhibited 1 of 3 clinical syndromes: 1) peracute death; 2) severe diarrhea leading to euthanasia or death; or 3) mild to moderate diarrhea followed by recovery. A given cage could contain both affected and unaffected mice. Outbreak 2 involved a small breeding colony (approximately 50 mice) of NOD. CB17-Prkdcscid/NCrCrl (NOD-scid) mice that had not received antibiotics or experimental manipulations. In both outbreaks, C. difficile was isolated, and toxins A and B were detected in intestinal content or feces. Histopathologic lesions highly suggestive of C. difficile enterotoxemia included fibrinonecrotizing and neutrophilic typhlocolitis with characteristic 'volcano' erosions or pseudomembrane formation. Genomic analysis of 4 isolates (3 from outbreak 1 and 1 from outbreak 2) revealed that these isolates were closely related to a pathogenic human isolate, CD 196. To our knowledge, this report is the first to describe naturally occurring outbreaks of C. difficile-associated typhlocolitis with significant morbidity and mortality in highly immunocompromised strains of mice.
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Affiliation(s)
- Kathleen G L Ma
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York
| | - Kvin Lertpiriyapong
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medicine, New York, New York
| | - Alessandra Piersigilli
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medicine, New York, New York; Laboratory for Comparative Pathology, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, and The Rockefeller University, New York, New York
| | - Irina Dobtsis
- Laboratory for Comparative Pathology, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, and The Rockefeller University, New York, New York
| | - Juliette R K Wipf
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medicine, New York, New York; Laboratory for Comparative Pathology, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medical College, and The Rockefeller University, New York, New York
| | - Eric R Littmann
- Infectious Diseases Service, Department of Medicine, Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Ingrid Leiner
- Infectious Diseases Service, Department of Medicine, Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Eric G Pamer
- Infectious Diseases Service, Department of Medicine, Immunology Program, Memorial Sloan-Kettering Cancer Center, New York, New York
| | - Rodolfo J Ricart Arbona
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medicine, New York, New York
| | - Neil S Lipman
- Tri-Institutional Training Program in Laboratory Animal Medicine and Science, Memorial Sloan-Kettering Cancer Center, Weill Cornell Medicine, and The Rockefeller University, New York, New York; Center for Comparative Medicine and Pathology, Memorial Sloan-Kettering Cancer Center and Weill Cornell Medicine, New York, New York;,
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26
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Wu Q, Savidge TC. Systems approaches for the clinical diagnosis of Clostridioides difficile infection. Transl Res 2020; 220:57-67. [PMID: 32272094 DOI: 10.1016/j.trsl.2020.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/02/2020] [Accepted: 03/09/2020] [Indexed: 12/18/2022]
Abstract
Clostridioides difficile infection (CDI) is an urgent threat to global public health. Patient susceptibility to C. difficile is highly dependent on host immune status and gut dysbiosis resulting in loss of protective microbiota consortia that prevent spore germination, pathogen colonization, and disease pathogenesis. Recent clinical studies highlight the problems of differentiating symptomatic CDI from asymptomatic C. difficile carriage in patients with diarrhea. In this review, we consider how integration of microbiome and host immune systems biology data may aid in the clinical diagnosis of CDI when validated against gold standard testing and combined with standard microbiology laboratory assays.
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Affiliation(s)
- Qinglong Wu
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas; Texas Children's Microbiome Center, Department of Pathology, Texas Children's Hospital, Houston, Texas
| | - Tor C Savidge
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas; Texas Children's Microbiome Center, Department of Pathology, Texas Children's Hospital, Houston, Texas.
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27
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Reed AD, Nethery MA, Stewart A, Barrangou R, Theriot CM. Strain-Dependent Inhibition of Clostridioides difficile by Commensal Clostridia Carrying the Bile Acid-Inducible ( bai) Operon. J Bacteriol 2020; 202:e00039-20. [PMID: 32179626 PMCID: PMC7221253 DOI: 10.1128/jb.00039-20] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 03/06/2020] [Indexed: 12/18/2022] Open
Abstract
Clostridioides difficile is one of the leading causes of antibiotic-associated diarrhea. Gut microbiota-derived secondary bile acids and commensal Clostridia that carry the bile acid-inducible (bai) operon are associated with protection from C. difficile infection (CDI), although the mechanism is not known. In this study, we hypothesized that commensal Clostridia are important for providing colonization resistance against C. difficile due to their ability to produce secondary bile acids, as well as potentially competing against C. difficile for similar nutrients. To test this hypothesis, we examined the abilities of four commensal Clostridia carrying the bai operon (Clostridium scindens VPI 12708, C. scindens ATCC 35704, Clostridium hiranonis, and Clostridium hylemonae) to convert cholate (CA) to deoxycholate (DCA) in vitro, and we determined whether the amount of DCA produced was sufficient to inhibit the growth of a clinically relevant C. difficile strain. We also investigated the competitive relationships between these commensals and C. difficile using an in vitro coculture system. We found that inhibition of C. difficile growth by commensal Clostridia supplemented with CA was strain dependent, correlated with the production of ∼2 mM DCA, and increased the expression of bai operon genes. We also found that C. difficile was able to outcompete all four commensal Clostridia in an in vitro coculture system. These studies are instrumental in understanding the relationship between commensal Clostridia and C. difficile in the gut, which is vital for designing targeted bacterial therapeutics. Future studies dissecting the regulation of the bai operon in vitro and in vivo and how this affects CDI will be important.IMPORTANCE Commensal Clostridia carrying the bai operon, such as C. scindens, have been associated with protection against CDI; however, the mechanism for this protection is unknown. Herein, we show four commensal Clostridia that carry the bai operon and affect C. difficile growth in a strain-dependent manner, with and without the addition of cholate. Inhibition of C. difficile by commensals correlated with the efficient conversion of cholate to deoxycholate, a secondary bile acid that inhibits C. difficile germination, growth, and toxin production. Competition studies also revealed that C. difficile was able to outcompete the commensals in an in vitro coculture system. These studies are instrumental in understanding the relationship between commensal Clostridia and C. difficile in the gut, which is vital for designing targeted bacterial therapeutics.
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Affiliation(s)
- A D Reed
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
| | - M A Nethery
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - A Stewart
- Molecular Education, Technology and Research Innovation Center, North Carolina State University, Raleigh, North Carolina, USA
| | - R Barrangou
- Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina, USA
| | - C M Theriot
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA
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28
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Rao RT, Sivakumar N, Jayakumar K. Analyses of Livestock-Associated Staphylococcus aureus Pan-Genomes Suggest Virulence Is Not Primary Interest in Evolution of Its Genome. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2020; 23:224-236. [PMID: 31009331 DOI: 10.1089/omi.2019.0005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Staphylococcus aureus is not only part of normal flora but also an opportunistic pathogen relevant to microbial genomics, public health, and veterinary medicine. In addition to being a well-known human pathogen, S. aureus causes various infections in economically important livestock animals such as cows, sheep, goats, and pigs. There are very few studies that have examined the pan-genome of S. aureus or the host-specific strains' pan-genomes. We report on livestock-associated S. aureus' (LA-SA) pan-genome and suggest that virulence is not the primary interest in evolution of its genome. LA-SA' complete genomes were retrieved from the NCBI and pan-genome was constructed by high-speed Roary pipeline. The pan-genome size was 4637 clusters, whereas 42.46% of the pan-genome was associated with the core genome. We found 1268 genes were associated with the strain-unique genome, and the remaining 1432 cluster with the accessory genome. COG (clusters of orthologous group of proteins) analysis of the core genes revealed 34% of clusters related to metabolism responsible for amino acid and inorganic ion transport (COG categories E and P), followed by carbohydrate metabolism (category G). Virulent gene analysis revealed the core genes responsible for antiphagocytosis and iron uptake. The fluidity of pan-genome was calculated as 0.082 ± 0.025. Importantly, the positive selection analysis suggested a slower rate of evolution among the LA-SA genomes. We call for comparative microbial and pan-genome research between human and LA-SA that can help further understand the evolution of virulence and thus inform future microbial diagnostics and drug discovery.
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Affiliation(s)
- Relangi Tulasi Rao
- 1 Department of Animal Behaviour & Physiology, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Natesan Sivakumar
- 2 Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Kannan Jayakumar
- 1 Department of Animal Behaviour & Physiology, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India
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29
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Impact of Antibiotic-Resistant Bacteria on Immune Activation and Clostridioides difficile Infection in the Mouse Intestine. Infect Immun 2020; 88:IAI.00362-19. [PMID: 31907198 DOI: 10.1128/iai.00362-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 12/20/2019] [Indexed: 01/20/2023] Open
Abstract
Antibiotic treatment of patients undergoing complex medical treatments can deplete commensal bacterial strains from the intestinal microbiota, thereby reducing colonization resistance against a wide range of antibiotic-resistant pathogens. Loss of colonization resistance can lead to marked expansion of vancomycin-resistant Enterococcus faecium (VRE), Klebsiella pneumoniae, and Escherichia coli in the intestinal lumen, predisposing patients to bloodstream invasion and sepsis. The impact of intestinal domination by these antibiotic-resistant pathogens on mucosal immune defenses and epithelial and mucin-mediated barrier integrity is unclear. We used a mouse model to study the impact of intestinal domination by antibiotic-resistant bacterial species and strains on the colonic mucosa. Intestinal colonization with K. pneumoniae, Proteus mirabilis, or Enterobacter cloacae promoted greater recruitment of neutrophils to the colonic mucosa. To test the hypothesis that the residual microbiota influences the severity of colitis caused by infection with Clostridioides difficile, we coinfected mice that were colonized with ampicillin-resistant bacteria with a virulent strain of C. difficile and monitored colonization and pathogenesis. Despite the compositional differences in the gut microbiota, the severity of C. difficile infection (CDI) and mortality did not differ significantly between mice colonized with different ampicillin-resistant bacterial species. Our results suggest that the virulence mechanisms enabling CDI and epithelial destruction outweigh the relatively minor impact of less-virulent antibiotic-resistant intestinal bacteria on the outcome of CDI.
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30
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Clostridioides difficile infection damages colonic stem cells via TcdB, impairing epithelial repair and recovery from disease. Proc Natl Acad Sci U S A 2020; 117:8064-8073. [PMID: 32198200 DOI: 10.1073/pnas.1915255117] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Gastrointestinal infections often induce epithelial damage that must be repaired for optimal gut function. While intestinal stem cells are critical for this regeneration process [R. C. van der Wath, B. S. Gardiner, A. W. Burgess, D. W. Smith, PLoS One 8, e73204 (2013); S. Kozar et al., Cell Stem Cell 13, 626-633 (2013)], how they are impacted by enteric infections remains poorly defined. Here, we investigate infection-mediated damage to the colonic stem cell compartment and how this affects epithelial repair and recovery from infection. Using the pathogen Clostridioides difficile, we show that infection disrupts murine intestinal cellular organization and integrity deep into the epithelium, to expose the otherwise protected stem cell compartment, in a TcdB-mediated process. Exposure and susceptibility of colonic stem cells to intoxication compromises their function during infection, which diminishes their ability to repair the injured epithelium, shown by altered stem cell signaling and a reduction in the growth of colonic organoids from stem cells isolated from infected mice. We also show, using both mouse and human colonic organoids, that TcdB from epidemic ribotype 027 strains does not require Frizzled 1/2/7 binding to elicit this dysfunctional stem cell state. This stem cell dysfunction induces a significant delay in recovery and repair of the intestinal epithelium of up to 2 wk post the infection peak. Our results uncover a mechanism by which an enteric pathogen subverts repair processes by targeting stem cells during infection and preventing epithelial regeneration, which prolongs epithelial barrier impairment and creates an environment in which disease recurrence is likely.
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31
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A comparative genomics approach identifies contact-dependent growth inhibition as a virulence determinant. Proc Natl Acad Sci U S A 2020; 117:6811-6821. [PMID: 32156726 DOI: 10.1073/pnas.1919198117] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Emerging evidence suggests the Pseudomonas aeruginosa accessory genome is enriched with uncharacterized virulence genes. Identification and characterization of such genes may reveal novel pathogenic mechanisms used by particularly virulent isolates. Here, we utilized a mouse bacteremia model to quantify the virulence of 100 individual P. aeruginosa bloodstream isolates and performed whole-genome sequencing to identify accessory genomic elements correlated with increased bacterial virulence. From this work, we identified a specific contact-dependent growth inhibition (CDI) system enriched among highly virulent P. aeruginosa isolates. CDI systems contain a large exoprotein (CdiA) with a C-terminal toxin (CT) domain that can vary between different isolates within a species. Prior work has revealed that delivery of a CdiA-CT domain upon direct cell-to-cell contact can inhibit replication of a susceptible target bacterium. Aside from mediating interbacterial competition, we observed our virulence-associated CdiA-CT domain to promote toxicity against mammalian cells in culture and lethality during mouse bacteremia. Structural and functional studies revealed this CdiA-CT domain to have in vitro tRNase activity, and mutations that abrogated this tRNAse activity in vitro also attenuated virulence. Furthermore, CdiA contributed to virulence in mice even in the absence of contact-dependent signaling. Overall, our findings indicate that this P. aeruginosa CDI system functions as both an interbacterial inhibition system and a bacterial virulence factor against a mammalian host. These findings provide an impetus for continued studies into the complex role of CDI systems in P. aeruginosa pathogenesis.
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Shen A. Clostridioides difficile Spores: Bile Acid Sensors and Trojan Horses of Transmission. Clin Colon Rectal Surg 2020; 33:58-66. [PMID: 32104157 DOI: 10.1055/s-0040-1701230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The Gram-positive, spore-forming bacterium, Clostridioides difficile is the leading cause of healthcare-associated infections in the United States, although it also causes a significant number of community-acquired infections. C. difficile infections, which range in severity from mild diarrhea to toxic megacolon, cost more to treat than matched infections, with an annual treatment cost of approximately $6 billion for almost half-a-million infections. These high-treatment costs are due to the high rates of C. difficile disease recurrence (>20%) and necessity for special disinfection measures. These complications arise in part because C. difficile makes metabolically dormant spores, which are the major infectious particle of this obligate anaerobe. These seemingly inanimate life forms are inert to antibiotics, resistant to commonly used disinfectants, readily disseminated, and capable of surviving in the environment for a long period of time. However, upon sensing specific bile salts in the vertebrate gut, C. difficile spores transform back into the vegetative cells that are responsible for causing disease. This review discusses how spores are ideal vectors for disease transmission and how antibiotics modulate this process. We also describe the resistance properties of spores and how they create challenges eradicating spores, as well as promote their spread. Lastly, environmental reservoirs of C. difficile spores and strategies for destroying them particularly in health care environments will be discussed.
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Affiliation(s)
- Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts
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Abstract
The past 10 years have been revolutionary for clostridial genetics. The rise of next-generation sequencing led to the availability of annotated whole-genome sequences of the important pathogenic clostridia: Clostridium perfringens, Clostridioides (Clostridium) difficile, and Clostridium botulinum, but also Paeniclostridium (Clostridium) sordellii and Clostridium tetani. These sequences were a prerequisite for the development of functional, sophisticated genetic tools for the pathogenic clostridia. A breakthrough came in the early 2000s with the development of TargeTron-based technologies specific for the clostridia, such as ClosTron, an insertional gene inactivation tool. The following years saw a plethora of new technologies being developed, mostly for C. difficile, but also for other members of the genus, including C. perfringens. A range of tools is now available, allowing researchers to precisely delete genes, change single nucleotides in the genome, complement deletions, integrate novel DNA into genomes, or overexpress genes. There are tools for forward genetics, including an inducible transposon mutagenesis system for C. difficile. As the latest addition to the tool kit, clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 technologies have also been adopted for the construction of single and multiple gene deletions in C. difficile. This article summarizes the key genetic technologies available to manipulate, study, and understand the pathogenic clostridia.
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Abbas A, Zackular JP. Microbe-microbe interactions during Clostridioides difficile infection. Curr Opin Microbiol 2020; 53:19-25. [PMID: 32088581 DOI: 10.1016/j.mib.2020.01.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 01/15/2020] [Accepted: 01/20/2020] [Indexed: 02/07/2023]
Abstract
Clostridioides difficile is the leading cause of hospital-acquired gastrointestinal infections and a major public health burden in the United States. C. difficile infection causes a spectrum of disease from mild diarrhea to severe complications such as pseudomembranous colitis, toxic megacolon and death. This broad range of disease is only partially explained by bacterial genetic factors, host genetics, comorbidities and previous drug exposures. Another important factor is the gut microbiome, the disruption of which results in a loss of colonization resistance to C. difficile. Here, we review how gut microbiota and their metabolites impact C. difficile virulence and influence disease.
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Affiliation(s)
- Arwa Abbas
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Joseph P Zackular
- Division of Protective Immunity, Department of Pathology and Laboratory Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, 19104, USA; Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Kulaylat AS, Buonomo EL, Scully KW, Hollenbeak CS, Cook H, Petri WA, Stewart DB. Development and Validation of a Prediction Model for Mortality and Adverse Outcomes Among Patients With Peripheral Eosinopenia on Admission for Clostridium difficile Infection. JAMA Surg 2019; 153:1127-1133. [PMID: 30208386 DOI: 10.1001/jamasurg.2018.3174] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Importance Recent evidence from an animal model suggests that peripheral loss of eosinophils in Clostridium difficile infection (CDI) is associated with severe disease. The ability to identify high-risk patients with CDI as early as the time of admission could improve outcomes by guiding management decisions. Objective To construct a model using clinical indices readily available at the time of hospital admission, including peripheral eosinophil counts, to predict inpatient mortality in patients with CDI. Design, Setting, and Participants In a cohort study, a total of 2065 patients admitted for CDI through the emergency department of 2 tertiary referral centers from January 1, 2005, to December 31, 2015, formed a training and a validation cohort. The sample was stratified by admission eosinophil count (0.0 cells/μL or >0.0 cells/μL), and multivariable logistic regression was used to construct a predictive model for inpatient mortality as well as other disease-related outcomes. Main Outcomes and Measures Inpatient mortality was the primary outcome. Secondary outcomes included the need for a monitored care setting, need for vasopressors, and rates of inpatient colectomy. Results Of the 2065 patients in the study, 1092 (52.9%) were women and patients had a mean (SD) age of 63.4 (18.4) years. Those with an undetectable eosinophil count at admission had increased in-hospital mortality in both the training (odds ratio [OR], 2.01; 95% CI, 1.08-3.73; P = .03) and validation (OR, 2.26; 95% CI, 1.33-3.83; P = .002) cohorts in both univariable and multivariable analysis. Undetectable eosinophil counts were also associated with indicators of severe sepsis, such as admission to monitored care settings (OR, 1.40; 95% CI, 1.06-1.86), the need for vasopressors (OR, 2.08; 95% CI, 1.32-3.28), and emergency total colectomy (OR, 2.56; 95% CI, 1.12-5.87). Other significant predictors of mortality at admission included increasing comorbidity burden (for each 1-unit increase: OR, 1.13; 95% CI, 1.05-1.22) and lower systolic blood pressures (for each 1-mm Hg increase: OR, 0.99; 95% CI, 0.98-1.00). In a subgroup analysis of patients presenting without initial tachycardia or hypotension, only patients with undetectable admission eosinophil counts, but not those with an elevated white blood cell count, had significantly increased odds of inpatient mortality (OR, 5.76; 95% CI, 1.99-16.64). Conclusions and Relevance This study describes a simple, widely available, inexpensive model predicting CDI severity and mortality to identify at-risk patients at the time of admission.
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Affiliation(s)
- Audrey S Kulaylat
- Department of Surgery, Pennsylvania State University, College of Medicine, Hershey
| | - Erica L Buonomo
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville
| | - Kenneth W Scully
- Department of Public Health Sciences, University of Virginia, Charlottesville
| | - Christopher S Hollenbeak
- Department of Surgery, Pennsylvania State University, College of Medicine, Hershey.,Department of Public Health Sciences, Pennsylvania State University, College of Medicine, Hershey
| | - Heather Cook
- Department of Statistics, University of Virginia, Charlottesville
| | - William A Petri
- Department of Microbiology, Immunology and Cancer Biology, University of Virginia Health System, Charlottesville.,Department of Medicine, University of Virginia Health System, Charlottesville.,Department of Pathology, University of Virginia Health System, Charlottesville
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Jones JA, Prior AM, Marreddy RKR, Wahrmund RD, Hurdle JG, Sun D, Hevener KE. Small-Molecule Inhibition of the C. difficile FAS-II Enzyme, FabK, Results in Selective Activity. ACS Chem Biol 2019; 14:1528-1535. [PMID: 31184849 DOI: 10.1021/acschembio.9b00293] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Clostridioides difficile infection (CDI) is a leading cause of significant morbidity, mortality, and healthcare-related costs in the United States. After standard therapy, recurrence rates remain high, and multiple recurrences are not uncommon. Causes include treatments employing broad-spectrum agents that disrupt the normal host microbiota, as well as treatment-resistant spore formation by C. difficile. Thus, novel druggable anti-C. difficile targets that promote narrow-spectrum eradication and inhibition of sporulation are desired. As a critical rate-limiting step within the FAS-II bacterial fatty acid synthesis pathway, which supplies precursory component phospholipids found in bacterial cytoplasmic and spore-mediated membranes, enoyl-acyl carrier protein (ACP) reductase II (FabK) represents such a target. FabK is essential in C. difficile (CdFabK) and is structurally and mechanistically distinct from other isozymes found in gut microbiota species, making CdFabK an attractive narrow-spectrum target. We report here the kinetic evaluation of CdFabK, the biochemical activity of a series of phenylimidazole analogues, and microbiological data suggesting these compounds' selective antibacterial activity against C. difficile versus several other prominent gut organisms. The compounds display promising, selective, low micromolar CdFabK inhibitory activity without significantly affecting the growth of other gut organisms, and the series prototype (1b) is shown to be competitive for the CdFabK cofactor and uncompetitive for the substrate. A series analogue (1g) shows maintained inhibitory activity while also possessing increased solubility. These findings represent the basis for future drug discovery efforts by characterizing the CdFabK enzyme while demonstrating its druggability and potential role as a narrow-spectrum antidifficile target.
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Affiliation(s)
- Jesse A. Jones
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee 38163, United States
| | - Allan M. Prior
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, Hawaii, 96720, United States
| | - Ravi K. R. Marreddy
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas 77030, United States
| | - Rebecca D. Wahrmund
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee 38163, United States
| | - Julian G. Hurdle
- Center for Infectious and Inflammatory Diseases, Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, Texas 77030, United States
| | - Dianqing Sun
- Department of Pharmaceutical Sciences, The Daniel K. Inouye College of Pharmacy, University of Hawaii at Hilo, Hilo, Hawaii, 96720, United States
| | - Kirk E. Hevener
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee 38163, United States
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Cao H, Wong SCY, Yam WC, Liu MCJ, Chow KH, Wu AKL, Ho PL. Genomic investigation of a sequence type 67 Clostridium difficile causing community-acquired fulminant colitis in Hong Kong. Int J Med Microbiol 2019; 309:270-273. [DOI: 10.1016/j.ijmm.2019.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/24/2019] [Accepted: 05/10/2019] [Indexed: 12/20/2022] Open
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Yong C, Lim J, Kim B, Park D, Oh S. Suppressive effect ofLactobacillus fermentumLim2 onClostridioides difficile027 toxin production. Lett Appl Microbiol 2019; 68:386-393. [DOI: 10.1111/lam.13124] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/24/2019] [Accepted: 01/28/2019] [Indexed: 01/05/2023]
Affiliation(s)
- C.C. Yong
- Division of Animal Science Chonnam National University Gwangju Korea
| | - J. Lim
- Division of Animal Science Chonnam National University Gwangju Korea
| | - B.‐K. Kim
- Korea Food Research Institute Jeollabuk‐do Korea
| | - D.‐J. Park
- Korea Food Research Institute Jeollabuk‐do Korea
| | - S. Oh
- Division of Animal Science Chonnam National University Gwangju Korea
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Sievers S, Metzendorf NG, Dittmann S, Troitzsch D, Gast V, Tröger SM, Wolff C, Zühlke D, Hirschfeld C, Schlüter R, Riedel K. Differential View on the Bile Acid Stress Response of Clostridioides difficile. Front Microbiol 2019; 10:258. [PMID: 30833939 PMCID: PMC6387971 DOI: 10.3389/fmicb.2019.00258] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/31/2019] [Indexed: 12/16/2022] Open
Abstract
Clostridioides difficile is an intestinal human pathogen that uses the opportunity of a depleted microbiota to cause an infection. It is known, that the composition of the intestinal bile acid cocktail has a great impact on the susceptibility toward a C. difficile infection. However, the specific response of growing C. difficile cells to diverse bile acids on the molecular level has not been described yet. In this study, we recorded proteome signatures of shock and long-term (LT) stress with the four main bile acids cholic acid (CA), chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), and lithocholic acid (LCA). A general overlapping response to all tested bile acids could be determined particularly in shock experiments which appears plausible in the light of their common steroid structure. However, during LT stress several proteins showed an altered abundance in the presence of only a single or a few of the bile acids indicating the existence of specific adaptation mechanisms. Our results point at a differential induction of the groEL and dnaKJgrpE chaperone systems, both belonging to the class I heat shock genes. Additionally, central metabolic pathways involving butyrate fermentation and the reductive Stickland fermentation of leucine were effected, although CA caused a proteome signature different from the other three bile acids. Furthermore, quantitative proteomics revealed a loss of flagellar proteins in LT stress with LCA. The absence of flagella could be substantiated by electron microscopy which also indicated less flagellated cells in the presence of DCA and CDCA and no influence on flagella formation by CA. Our data break down the bile acid stress response of C. difficile into a general and a specific adaptation. The latter cannot simply be divided into a response to primary and secondary bile acids, but rather reflects a complex and variable adaptation process enabling C. difficile to survive and to cause an infection in the intestinal tract.
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Affiliation(s)
- Susanne Sievers
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Nicole G Metzendorf
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Silvia Dittmann
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Daniel Troitzsch
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Viola Gast
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Sophie Marlen Tröger
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Christian Wolff
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Daniela Zühlke
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Claudia Hirschfeld
- Department of Microbial Proteomics, Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
| | - Rabea Schlüter
- Imaging Center of the Department of Biology, University of Greifswald, Greifswald, Germany
| | - Katharina Riedel
- Institute of Microbiology, Center for Functional Genomics of Microbes, University of Greifswald, Greifswald, Germany
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Sanchez DA, Martinez LR. Underscoring interstrain variability and the impact of growth conditions on associated antimicrobial susceptibilities in preclinical testing of novel antimicrobial drugs. Crit Rev Microbiol 2019; 45:51-64. [PMID: 30522365 PMCID: PMC6905375 DOI: 10.1080/1040841x.2018.1538934] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/22/2018] [Accepted: 10/12/2018] [Indexed: 01/12/2023]
Abstract
In the era of multidrug resistant (MDR) organisms, reliable efficacy testing of novel antimicrobials during developmental stages is of paramount concern prior to introduction in clinical trials. Unfortunately, interstrain variability is often underappreciated when appraising the efficacy of innovative antimicrobials as preclinical testing of a limited number of standardized strains in unvarying conditions does not account for the vastness and potential for hyperdiversity among and within microbial populations. In this review, the importance of accounting for interstrain variability's potential to impact breadth of novel drug efficacy evaluation in the early stages of drug development will be discussed. Additionally, testing under varying microenvironmental conditions that may influence drug efficacy will be discussed. Biofilm growth, the influence of polymicrobial growth, mechanisms of antimicrobial resistance, pH, anaerobic conditions, and other virulence factors are some of critical issues that require more attention and standardization during preclinical drug efficacy evaluation. Furthermore, potential solutions for addressing this issue in pre-clinical antimicrobial development are proposed via centralization of microbial characterization and drug target databases, testing of a large number of clinical strains, inclusion of mutator strains in testing and the use of growth parameter mathematical models for testing.
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Affiliation(s)
- David A. Sanchez
- Howard University College of Medicine, Washington, DC, USA
- Brigham and Women’s Hospital, Boston, MA, USA
| | - Luis R. Martinez
- Department of Biological Sciences, The Border Biomedical Research Center, University of Texas at El Paso, TX, USA
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41
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Sorbara MT, Pamer EG. Interbacterial mechanisms of colonization resistance and the strategies pathogens use to overcome them. Mucosal Immunol 2019; 12:1-9. [PMID: 29988120 PMCID: PMC6312114 DOI: 10.1038/s41385-018-0053-0] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/15/2018] [Accepted: 05/27/2018] [Indexed: 02/08/2023]
Abstract
The communities of bacteria that reside in the intestinal tract are in constant competition within this dynamic and densely colonized environment. At homeostasis, the equilibrium that exists between these species and strains is shaped by their metabolism and also by pathways of active antagonism, which drive competition with related and unrelated strains. Importantly, these normal activities contribute to colonization resistance by the healthy microbiota, which includes the ability to prevent the expansion of potential pathogens. Disruption of the microbiota, resulting from, for example, inflammation or antibiotic use, can reduce colonization resistance. Pathogens that engraft following disruption of the microbiota are often adapted to expand into newly created niches and compete in an altered gut environment. In this review, we examine both the interbacterial mechanisms of colonization resistance and the strategies of pathogenic strains to exploit gaps in colonization resistance.
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Affiliation(s)
- Matthew T. Sorbara
- Immunology Program, Sloan Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
| | - Eric G. Pamer
- Immunology Program, Sloan Kettering Institute, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Center for Microbes, Inflammation and Cancer, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
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Aliramezani A, Talebi M, Baghani A, Hajabdolbaghi M, Salehi M, Abdollahi A, Afhami S, Marjani M, Golbabaei F, Boroumand MA, Sarrafnejad A, Yaseri M, Ghourchian S, Douraghi M. Pathogenicity locus determinants and toxinotyping of Clostridioides difficile isolates recovered from Iranian patients. New Microbes New Infect 2018; 25:52-57. [PMID: 30094031 PMCID: PMC6072886 DOI: 10.1016/j.nmni.2018.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 06/25/2018] [Accepted: 07/05/2018] [Indexed: 01/08/2023] Open
Abstract
Little is known about the toxin profiles, toxinotypes and variations of toxin Clostridioides difficile C (tcdC) in Iranian C. difficile isolates. A total of 818 stool specimens were obtained from outpatients (n = 45) and hospitalized patients (n = 773) in Tehran, Iran, from 2011 to 2017. The 44 C. difficile isolates were subjected to PCR of toxin C. difficile A (tcdA), toxin C. difficile B (tcdB), tcdA 3′-end deletion, toxinotyping and sequencing of the tcdC gene. Thirty-eight isolates (86.36%) were identified as tcdA and tcdB positive, and the remaining six isolates (13.63%) were nontoxigenic. All tcdA- and tcdB-positive isolates yielded an amplicon of 2535 bp by PCR for the tcdA 3′ end. Fourteen (36.84%), seventeen (44.73%) and seven (18.43%) isolates belonged to wild-type, toxin C. difficile C subclone3 (tcdC-sc3) and tcdC-A genotype of tcdC, respectively. Thirty-one isolates (81.57%) belonged to toxinotype 0, and seven isolates (18.42%) were classified as toxinotype V. This study provides evidence for the circulation of historical and hypervirulent isolates in the healthcare and community settings. Furthermore, it was also demonstrated that the tcdC-A genotype and toxinotype V are not uncommon among Iranian C. difficile isolates.
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Affiliation(s)
- A Aliramezani
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran, Iran
| | - M Talebi
- Department of Microbiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - A Baghani
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran, Iran
| | - M Hajabdolbaghi
- Department of Infectious Diseases and Tropical Medicine, Faculty of Medicine, Tehran, Iran
| | - M Salehi
- Department of Infectious Diseases and Tropical Medicine, Faculty of Medicine, Tehran, Iran
| | - A Abdollahi
- Department of Pathology, Imam Hospital Complex, Tehran, Iran
| | - S Afhami
- Department of Infectious Diseases, Shariati Hospital, Tehran, Iran
| | - M Marjani
- Clinical Tuberculosis and Epidemiology Research Center, National Research Institute of Tuberculosis and Lung Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - F Golbabaei
- Department of Occupational Health, School of Public Health, Medical Sciences, University of Tehran, Tehran, Iran
| | - M A Boroumand
- Department of Pathology, Tehran Heart Center, Tehran, Iran
| | - A Sarrafnejad
- Department of Immunology, School of Public Health, Tehran, Iran
| | - M Yaseri
- Department of Epidemiology and Biostatistics, School of Public Health, Tehran, Iran
| | - S Ghourchian
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran, Iran
| | - M Douraghi
- Division of Microbiology, Department of Pathobiology, School of Public Health, Tehran, Iran.,Food Microbiology Research Center, Tehran University of Medical Sciences, Tehran, Iran
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Epidemiological aspects of healthcare-associated infections and microbial genomics. Eur J Clin Microbiol Infect Dis 2018; 37:823-831. [PMID: 29340898 DOI: 10.1007/s10096-017-3170-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 12/19/2017] [Indexed: 12/27/2022]
Abstract
Hospital-acquired infections (HAIs) are a cause of continuously increasing morbidity and mortality. Most of these infections are caused by a limited set of bacterial species, which share the capability to efficiently spread from patient to patient and to easily acquire antibiotic resistance determinants. This renders correct and rapid species identification and antibiotic susceptibility testing (AST) important and underscores the relevance of bacterial epidemiological typing. The latter is needed for the sensitive detection and exact tracing of nosocomial spread of these potentially multidrug-resistant microorganisms (MDRO). Many microbial typing technologies have been developed and put to some level of executive practice, but it seems that the continued evolution in methodology has currently reached an apex: there is likely to be scientific and practical consensus on the ultimate typing potential of bacterial whole-genome sequencing (WGS). The possibility to perform pan-genomic nucleotide-to-nucleotide comparisons between strains belonging to a single species and to detect even minute changes in nucleotide order will identify closely related organisms, while upon accumulation of such mutations, independent descend can be assumed. Calibration of difference levels [i.e. number of single nucleotide polymorphisms (SNPs)] into categories of inter-strain relatedness needs to be performed in order to generate robust, portable typing schemes. Here, we will briefly discuss the state of affairs regarding bacterial epidemiology based upon WGS, its relatedness with the nomenclature of former typing approaches and the continuing need for a global typing language.
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