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Naudet J, d'Orbcastel ER, Bouvier T, Godreuil S, Dyall S, Bouvy S, Rieuvilleneuve F, Restrepo-Ortiz CX, Bettarel Y, Auguet JC. Identifying macroplastic pathobiomes and antibiotic resistance in a subtropical fish farm. MARINE POLLUTION BULLETIN 2023; 194:115267. [PMID: 37487429 DOI: 10.1016/j.marpolbul.2023.115267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 06/21/2023] [Accepted: 07/04/2023] [Indexed: 07/26/2023]
Abstract
Macroplastics are ubiquitous in aquaculture ecosystems. However, to date the potential role of plastics as a support for bacterial biofilm that can include potential human pathogenic bacteria (PHPB) and antibiotic-resistant bacteria (ARB) has been largely overlooked. In this study, we used a combination of metabarcoding and standard antibiotic susceptibility testing to study the pathobiome and resistome of macroplastics, fish guts and the environment in a marine aquaculture farm in Mauritius. Aquaculture macroplastics were found to be higher in PHPB, dominated by the Vibrionaceae family (0.34 % of the total community), compared with environmental samples. Moreover, isolates from aquaculture plastics showed higher significant multiple antibiotic resistance (MAR) compared to non-plastic samples of seawater, sediment and fish guts. These results suggest that plastics act as a reservoir and fomite of PHPB and ARB in aquaculture, potentially threatening the health of farmed fish and human consumers.
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Affiliation(s)
- Jeanne Naudet
- UMR MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France.
| | - Emmanuelle Roque d'Orbcastel
- UMR MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Sète, France; IOC, Indian Ocean Commission, Blue Tower, Rue de l'Institut, Ebène, Mauritius
| | - Thierry Bouvier
- UMR MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
| | - Sylvain Godreuil
- UMR MIVEGEC IRD-CNRS-Université de Montpellier, IRD, Montpellier, France
| | - Sabrina Dyall
- Molecular Life Sciences Pole of Research Excellence, Department of Biosciences and Ocean Studies, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius
| | - Simon Bouvy
- Ferme Marine de Mahébourg Ltd. Royal Road, Pointe aux Feuilles, Mauritius
| | | | | | - Yvan Bettarel
- UMR MARBEC, Univ Montpellier, CNRS, Ifremer, IRD, Montpellier, France
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Abstract
Anthrax has been feared for its high mortality in animals and humans for centuries. The etiologic agent is considered a potentially devastating bioweapon, and since 1876―when Robert Koch demonstrated that Bacillus anthracis caused anthrax―it has been considered the sole cause of the disease. Anthrax is, however, a toxin-mediated disease. The toxins edema toxin and lethal toxin are formed from protein components encoded for by the pXO1 virulence plasmid present in pathogenic B. anthracis strains. However, other members of the Bacillus cereus group, to which B. anthracis belongs, have recently been shown to harbor the pXO1 plasmid and produce anthrax toxins. Infection with these Bacillus cereus group organisms produces a disease clinically similar to anthrax. This suggests that anthrax should be defined by the exotoxins encoded for by the pXO1 plasmid rather than the bacterial species it has historically been associated with, and that the definition of anthrax should be expanded to include disease caused by any member of the B. cereus group containing the toxin-producing pXO1 plasmid or anthrax toxin genes specifically.
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Baldwin VM. You Can't B. cereus - A Review of Bacillus cereus Strains That Cause Anthrax-Like Disease. Front Microbiol 2020; 11:1731. [PMID: 32973690 PMCID: PMC7468541 DOI: 10.3389/fmicb.2020.01731] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 07/02/2020] [Indexed: 12/15/2022] Open
Abstract
Emerging strains of Bacillus cereus, traditionally considered a self-limiting foodborne pathogen, have been associated with anthrax-like disease in mammals, including humans. The strains have emerged by divergent evolution and, as exchange of genetic material in the Bacillus genus occurs naturally, it is possible that further isolates will be identified in the future. The strains vary in their genotypes and phenotypes, combining traits of both B. cereus and B. anthracis species. Cases of anthrax-like disease associated with these strains result in similar symptoms and mortality rates as those caused by B. anthracis. The strains are susceptible to frontline antibiotics used in the treatment of anthrax and existing vaccines provide protection in animal models. The emergence of these strains has reignited the debate surrounding classification of the B. cereus sensu lato group and serves as a reminder that the field of medical microbiology is constantly changing and remains an important and ongoing area of research.
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Abstract
The Bacillus cereus group includes several Bacillus species with closely related phylogeny. The most well-studied members of the group, B. anthracis, B. cereus, and B. thuringiensis, are known for their pathogenic potential. Here, we present the historical rationale for speciation and discuss shared and unique features of these bacteria. Aspects of cell morphology and physiology, and genome sequence similarity and gene synteny support close evolutionary relationships for these three species. For many strains, distinct differences in virulence factor synthesis provide facile means for species assignment. B. anthracis is the causative agent of anthrax. Some B. cereus strains are commonly recognized as food poisoning agents, but strains can also cause localized wound and eye infections as well as systemic disease. Certain B. thuringiensis strains are entomopathogens and have been commercialized for use as biopesticides, while some strains have been reported to cause infection in immunocompromised individuals. In this article we compare and contrast B. anthracis, B. cereus, and B. thuringiensis, including ecology, cell structure and development, virulence attributes, gene regulation and genetic exchange systems, and experimental models of disease.
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Blaustein RA, McFarland AG, Ben Maamar S, Lopez A, Castro-Wallace S, Hartmann EM. Pangenomic Approach To Understanding Microbial Adaptations within a Model Built Environment, the International Space Station, Relative to Human Hosts and Soil. mSystems 2019; 4:e00281-18. [PMID: 30637341 PMCID: PMC6325168 DOI: 10.1128/msystems.00281-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/07/2018] [Indexed: 12/11/2022] Open
Abstract
Understanding underlying mechanisms involved in microbial persistence in the built environment (BE) is essential for strategically mitigating potential health risks. To test the hypothesis that BEs impose selective pressures resulting in characteristic adaptive responses, we performed a pangenomics meta-analysis leveraging 189 genomes (accessed from GenBank) of two epidemiologically important taxa, Bacillus cereus and Staphylococcus aureus, isolated from various origins: the International Space Station (ISS; a model BE), Earth-based BEs, soil, and humans. Our objectives were to (i) identify differences in the pangenomic composition of generalist and host-associated organisms, (ii) characterize genes and functions involved in BE-associated selection, and (iii) identify genomic signatures of ISS-derived strains of potential relevance for astronaut health. The pangenome of B. cereus was more expansive than that of S. aureus, which had a dominant core component. Genomic contents of both taxa significantly correlated with isolate origin, demonstrating an importance for biogeography and potential niche adaptations. ISS/BE-enriched functions were often involved in biosynthesis, catabolism, materials transport, metabolism, and stress response. Multiple origin-enriched functions also overlapped across taxa, suggesting conserved adaptive processes. We further characterized two mobile genetic elements with local neighborhood genes encoding biosynthesis and stress response functions that distinctively associated with B. cereus from the ISS. Although antibiotic resistance genes were present in ISS/BE isolates, they were also common in counterparts elsewhere. Overall, despite differences in microbial lifestyle, some functions appear common to remaining viable in the BE, and those functions are not typically associated with direct impacts on human health. IMPORTANCE The built environment contains a variety of microorganisms, some of which pose critical human health risks (e.g., hospital-acquired infection, antibiotic resistance dissemination). We uncovered a combination of complex biological functions that may play a role in bacterial survival under the presumed selective pressures in a model built environment-the International Space Station-by using an approach to compare pangenomes of bacterial strains from two clinically relevant species (B. cereus and S. aureus) isolated from both built environments and humans. Our findings suggest that the most crucial bacterial functions involved in this potential adaptive response are specific to bacterial lifestyle and do not appear to have direct impacts on human health.
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Affiliation(s)
- Ryan A. Blaustein
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| | - Alexander G. McFarland
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| | - Sarah Ben Maamar
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
| | - Alberto Lopez
- Department of Microbiology-Immunology, Northwestern University, Evanston, Illinois, USA
| | - Sarah Castro-Wallace
- Biomedical Research and Environmental Sciences Division, NASA Johnson Space Center, Houston, Texas, USA
| | - Erica M. Hartmann
- Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois, USA
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Scarff JM, Seldina YI, Vergis JM, Ventura CL, O’Brien AD. Expression and contribution to virulence of each polysaccharide capsule of Bacillus cereus strain G9241. PLoS One 2018; 13:e0202701. [PMID: 30133532 PMCID: PMC6105005 DOI: 10.1371/journal.pone.0202701] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 08/06/2018] [Indexed: 12/03/2022] Open
Abstract
Bacillus cereus strain G9241 was isolated from a patient with pneumonia who had an anthrax-like illness. Like Bacillus anthracis, the virulence of G9241 is dependent on two large plasmids. In G9241 those plasmids are pBCXO1 and pBC210. There is a multi-gene capsule locus on each of these virulence plasmids, and both capsules are produced by G9241 in vitro and in mice. The hasACB operon on pBCXO1 is responsible for production of a hyaluronic acid (HA) capsule. The locus on pBC210 encodes a putative tetrasaccharide (TS) capsule that assembles in a Wzy-dependent manner. We found that the pBC210 capsule locus is transcribed as two operons and identified the promoter regions responsible for transcription. We constructed isogenic mutants to assess the role of genes in the two TS capsule operons in production of the capsule. Spores of strains deficient in production of either the HA or TS capsule were inoculated subcutaneously or intranasally into A/J and C57BL/6 mice to determine the lethal dose 50% of each bacterial mutant by each route of infection. The loss of the HA capsule attenuated G9241 more than the loss of the TS capsule for both infection routes in both mouse strains. Overall, our data further characterize the unique TS capsule on pBC210 and demonstrate that the two capsules do not have the same impact on virulence of G9241.
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Affiliation(s)
- Jennifer M. Scarff
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Yuliya I. Seldina
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - James M. Vergis
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Christy L. Ventura
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
| | - Alison D. O’Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States of America
- * E-mail:
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Rapid, High-Throughput Identification of Anthrax-Causing and Emetic Bacillus cereus Group Genome Assemblies via BTyper, a Computational Tool for Virulence-Based Classification of Bacillus cereus Group Isolates by Using Nucleotide Sequencing Data. Appl Environ Microbiol 2017. [PMID: 28625989 PMCID: PMC5561296 DOI: 10.1128/aem.01096-17] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Bacillus cereus group comprises nine species, several of which are pathogenic. Differentiating between isolates that may cause disease and those that do not is a matter of public health and economic importance, but it can be particularly challenging due to the high genomic similarity within the group. To this end, we have developed BTyper, a computational tool that employs a combination of (i) virulence gene-based typing, (ii) multilocus sequence typing (MLST), (iii) panC clade typing, and (iv) rpoB allelic typing to rapidly classify B. cereus group isolates using nucleotide sequencing data. BTyper was applied to a set of 662 B. cereus group genome assemblies to (i) identify anthrax-associated genes in non-B. anthracis members of the B. cereus group, and (ii) identify assemblies from B. cereus group strains with emetic potential. With BTyper, the anthrax toxin genes cya, lef, and pagA were detected in 8 genomes classified by the NCBI as B. cereus that clustered into two distinct groups using k-medoids clustering, while either the B. anthracis poly-γ-d-glutamate capsule biosynthesis genes capABCDE or the hyaluronic acid capsule hasA gene was detected in an additional 16 assemblies classified as either B. cereus or Bacillus thuringiensis isolated from clinical, environmental, and food sources. The emetic toxin genes cesABCD were detected in 24 assemblies belonging to panC clades III and VI that had been isolated from food, clinical, and environmental settings. The command line version of BTyper is available at https://github.com/lmc297/BTyper. In addition, BMiner, a companion application for analyzing multiple BTyper output files in aggregate, can be found at https://github.com/lmc297/BMiner. IMPORTANCEBacillus cereus is a foodborne pathogen that is estimated to cause tens of thousands of illnesses each year in the United States alone. Even with molecular methods, it can be difficult to distinguish nonpathogenic B. cereus group isolates from their pathogenic counterparts, including the human pathogen Bacillus anthracis, which is responsible for anthrax, as well as the insect pathogen B. thuringiensis. By using the variety of typing schemes employed by BTyper, users can rapidly classify, characterize, and assess the virulence potential of any isolate using its nucleotide sequencing data.
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Scarff JM, Raynor MJ, Seldina YI, Ventura CL, Koehler TM, O'Brien AD. The roles of AtxA orthologs in virulence of anthrax-like Bacillus cereus G9241. Mol Microbiol 2016; 102:545-561. [PMID: 27490458 DOI: 10.1111/mmi.13478] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2016] [Indexed: 12/16/2022]
Abstract
AtxA is a critical transcriptional regulator of plasmid-encoded virulence genes in Bacillus anthracis. Bacillus cereus G9241, which caused an anthrax-like infection, has two virulence plasmids, pBCXO1 and pBC210, that each harbor toxin genes and a capsule locus. G9241 also produces two orthologs of AtxA: AtxA1, encoded on pBCXO1, and AtxA2, encoded on pBC210. The amino acid sequence of AtxA1 is identical to that of AtxA from B. anthracis, while the sequences of AtxA1 and AtxA2 are 79% identical and 91% similar to one another. We found by qRT-PCR that AtxA1 and AtxA2 function as positive regulators of toxin (AtxA1) and capsule operon (both) transcription in G9241 and that a ΔatxA1 mutant produced lower levels of the anthrax toxins and no hyaluronic acid capsule. Deletion of atxA1 or atxA2 decreased the virulence of spores administered intranasally or subcutaneously to C57BL/6 mice but not to A/J mice, and deletion of both genes rendered spores avirulent in A/J mice. In addition, unlike AtxA1, AtxA2 did not form stable homomultimers in vitro, although AtxA1 and AtxA2 formed heterodimers. Our data show that AtxA1 is the primary regulator of G9241 virulence factor expression and that AtxA1 and AtxA2 are both required for full virulence.
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Affiliation(s)
- Jennifer M Scarff
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Malik J Raynor
- Department of Microbiology and Molecular Genetics, The University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Yuliya I Seldina
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Christy L Ventura
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
| | - Theresa M Koehler
- Department of Microbiology and Molecular Genetics, The University of Texas Health Sciences Center at Houston, Houston, TX, USA
| | - Alison D O'Brien
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, USA
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Marston CK, Ibrahim H, Lee P, Churchwell G, Gumke M, Stanek D, Gee JE, Boyer AE, Gallegos-Candela M, Barr JR, Li H, Boulay D, Cronin L, Quinn CP, Hoffmaster AR. Anthrax Toxin-Expressing Bacillus cereus Isolated from an Anthrax-Like Eschar. PLoS One 2016; 11:e0156987. [PMID: 27257909 PMCID: PMC4892579 DOI: 10.1371/journal.pone.0156987] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/23/2016] [Indexed: 11/18/2022] Open
Abstract
Bacillus cereus isolates have been described harboring Bacillus anthracis toxin genes, most notably B. cereus G9241, and capable of causing severe and fatal pneumonias. This report describes the characterization of a B. cereus isolate, BcFL2013, associated with a naturally occurring cutaneous lesion resembling an anthrax eschar. Similar to G9241, BcFL2013 is positive for the B. anthracis pXO1 toxin genes, has a multi-locus sequence type of 78, and a pagA sequence type of 9. Whole genome sequencing confirms the similarity to G9241. In addition to the chromosome having an average nucleotide identity of 99.98% when compared to G9241, BcFL2013 harbors three plasmids with varying homology to the G9241 plasmids (pBCXO1, pBC210 and pBFH_1). This is also the first report to include serologic testing of patient specimens associated with this type of B. cereus infection which resulted in the detection of anthrax lethal factor toxemia, a quantifiable serum antibody response to protective antigen (PA), and lethal toxin neutralization activity.
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Affiliation(s)
- Chung K. Marston
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
- * E-mail:
| | - Hisham Ibrahim
- Villages Regional Hospital, Lady Lake, FL, United States of America
| | - Philip Lee
- Bureau of Public Health Laboratories, Florida Department of Health, Jacksonville, FL, United States of America
| | - George Churchwell
- Bureau of Public Health Laboratories, Florida Department of Health, Jacksonville, FL, United States of America
| | - Megan Gumke
- Bureau of Epidemiology, Florida Department of Health, Tallahassee, FL, United States of America
| | - Danielle Stanek
- Bureau of Epidemiology, Florida Department of Health, Tallahassee, FL, United States of America
| | - Jay E. Gee
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Anne E. Boyer
- National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Maribel Gallegos-Candela
- National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - John R. Barr
- National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Han Li
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Darbi Boulay
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Li Cronin
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Conrad P. Quinn
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
| | - Alex R. Hoffmaster
- National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA, United States of America
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