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Burcham ZM, Belk AD, McGivern BB, Bouslimani A, Ghadermazi P, Martino C, Shenhav L, Zhang AR, Shi P, Emmons A, Deel HL, Xu ZZ, Nieciecki V, Zhu Q, Shaffer M, Panitchpakdi M, Weldon KC, Cantrell K, Ben-Hur A, Reed SC, Humphry GC, Ackermann G, McDonald D, Chan SHJ, Connor M, Boyd D, Smith J, Watson JMS, Vidoli G, Steadman D, Lynne AM, Bucheli S, Dorrestein PC, Wrighton KC, Carter DO, Knight R, Metcalf JL. A conserved interdomain microbial network underpins cadaver decomposition despite environmental variables. Nat Microbiol 2024; 9:595-613. [PMID: 38347104 PMCID: PMC10914610 DOI: 10.1038/s41564-023-01580-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/08/2023] [Indexed: 03/07/2024]
Abstract
Microbial breakdown of organic matter is one of the most important processes on Earth, yet the controls of decomposition are poorly understood. Here we track 36 terrestrial human cadavers in three locations and show that a phylogenetically distinct, interdomain microbial network assembles during decomposition despite selection effects of location, climate and season. We generated a metagenome-assembled genome library from cadaver-associated soils and integrated it with metabolomics data to identify links between taxonomy and function. This universal network of microbial decomposers is characterized by cross-feeding to metabolize labile decomposition products. The key bacterial and fungal decomposers are rare across non-decomposition environments and appear unique to the breakdown of terrestrial decaying flesh, including humans, swine, mice and cattle, with insects as likely important vectors for dispersal. The observed lockstep of microbial interactions further underlies a robust microbial forensic tool with the potential to aid predictions of the time since death.
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Affiliation(s)
- Zachary M Burcham
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Microbiology, University of Tennessee, Knoxville, TN, USA
| | - Aeriel D Belk
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA
- Department of Animal Sciences, Auburn University, Auburn, AL, USA
| | - Bridget B McGivern
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Amina Bouslimani
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, CA, USA
| | - Parsa Ghadermazi
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO, USA
| | - Cameron Martino
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Liat Shenhav
- Center for Studies in Physics and Biology, Rockefeller University, New York, NY, USA
- Institute for Systems Genetics, New York Grossman School of Medicine, New York University, New York, NY, USA
- Department of Computer Science, New York University, New York, NY, USA
| | - Anru R Zhang
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
- Department of Computer Science, Duke University, Durham, NC, USA
| | - Pixu Shi
- Department of Biostatistics and Bioinformatics, Duke University, Durham, NC, USA
| | - Alexandra Emmons
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA
| | - Heather L Deel
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Zhenjiang Zech Xu
- School of Food Science and Technology, Nanchang University, Nanchang, Jiangxi, China
| | - Victoria Nieciecki
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, USA
| | - Qiyun Zhu
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- School of Life Sciences, Arizona State University, Tempe, AZ, USA
- Center for Fundamental and Applied Microbiomics, Arizona State University, Tempe, AZ, USA
| | - Michael Shaffer
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - Morgan Panitchpakdi
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, CA, USA
| | - Kelly C Weldon
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, CA, USA
| | - Kalen Cantrell
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
| | - Asa Ben-Hur
- Department of Computer Science, Colorado State University, Fort Collins, CO, USA
| | - Sasha C Reed
- U.S. Geological Survey, Southwest Biological Science Center, Moab, UT, USA
| | - Greg C Humphry
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Gail Ackermann
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Daniel McDonald
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Siu Hung Joshua Chan
- Department of Chemical and Biological Engineering, Colorado State University, Fort Collins, CO, USA
| | - Melissa Connor
- Forensic Investigation Research Station, Colorado Mesa University, Grand Junction, CO, USA
| | - Derek Boyd
- Forensic Anthropology Center, Department of Anthropology, University of Tennessee, Knoxville, TN, USA
- Department of Social, Cultural, and Justice Studies, University of Tennessee at Chattanooga, Chattanooga, TN, USA
| | - Jake Smith
- Forensic Anthropology Center, Department of Anthropology, University of Tennessee, Knoxville, TN, USA
- Mid-America College of Funeral Service, Jeffersonville, IN, USA
| | - Jenna M S Watson
- Forensic Anthropology Center, Department of Anthropology, University of Tennessee, Knoxville, TN, USA
| | - Giovanna Vidoli
- Forensic Anthropology Center, Department of Anthropology, University of Tennessee, Knoxville, TN, USA
| | - Dawnie Steadman
- Forensic Anthropology Center, Department of Anthropology, University of Tennessee, Knoxville, TN, USA
| | - Aaron M Lynne
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Sibyl Bucheli
- Department of Biological Sciences, Sam Houston State University, Huntsville, TX, USA
| | - Pieter C Dorrestein
- Collaborative Mass Spectrometry Innovation Center, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, San Diego, CA, USA
| | - Kelly C Wrighton
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, USA
| | - David O Carter
- Laboratory of Forensic Taphonomy, Forensic Sciences Unit, School of Natural Sciences and Mathematics, Chaminade University of Honolulu, Honolulu, HI, USA
| | - Rob Knight
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- Department of Computer Science and Engineering, University of California San Diego, La Jolla, CA, USA
- Center for Microbiome Innovation, University of California San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Jessica L Metcalf
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, USA.
- Graduate Program in Cell and Molecular Biology, Colorado State University, Fort Collins, CO, USA.
- Humans and the Microbiome Program, Canadian Institute for Advanced Research, Toronto, Ontario, Canada.
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Burcham ZM, Weitzel MA, Hodges LD, Deel HL, Metcalf JL. A pilot study characterizing gravesoil bacterial communities a decade after swine decomposition. Forensic Sci Int 2021; 323:110782. [PMID: 33894685 DOI: 10.1016/j.forsciint.2021.110782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 04/05/2021] [Indexed: 11/29/2022]
Abstract
Vertebrate decomposition leads to an efflux of fluids rich with biochemicals and microbes from the carcass into the surrounding soil affecting the endogenous soil bacterial community. These perturbations are detectable in soils associated with carcasses (gravesoil) and influence soil bacterial ecology for years after the decomposition event, but it is unknown for how long. Measuring these impacts over extended timescales is critical to expanding vertebrate decomposition's role in the ecosystem and may provide useful information to forensic science. Using 16S rRNA gene amplicon data, this study surveyed bacterial composition in terrestrial soils associated with surface-exposed swine decomposition for 10 years after carcass placement. This pilot study utilizes the increased statistical power associated with repeated measure/within-subjects sampling to analyze bacterial diversity trends over time. Our results demonstrate that the soil bacterial diversity was significantly impacted by decomposition, with this impact being localized to the area underneath the carcass. Bacterial community dissimilarity was greatest 12 months postmortem before beginning recovery. Additionally, random forest regressions were utilized to determine 10 important genera for distinguishing decomposition timepoints, an important component of forensic investigations. Of these 10 genera, four were further analyzed for their significant relative abundance shifts underneath the carcass. This pilot study helps expand the current knowledge of long-term effects of carcass decomposition on soil bacterial communities, and is the first to our knowledge to characterize these communities temporally from placement through a decade of decomposition.
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Affiliation(s)
- Zachary M Burcham
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80525, USA.
| | - Misty A Weitzel
- Criminal Justice Department, Western Oregon University, Monmouth, OR 97361, USA.
| | - Larry D Hodges
- Department of Microbiology, Oregon State University, Corvallis, OR 97331, USA.
| | - Heather L Deel
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80525, USA.
| | - Jessica L Metcalf
- Department of Animal Sciences, Colorado State University, Fort Collins, CO 80525, USA.
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Spencer BL, Deng L, Patras KA, Burcham ZM, Sanches GF, Nagao PE, Doran KS. Cas9 Contributes to Group B Streptococcal Colonization and Disease. Front Microbiol 2019; 10:1930. [PMID: 31497003 PMCID: PMC6712506 DOI: 10.3389/fmicb.2019.01930] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 08/05/2019] [Indexed: 12/20/2022] Open
Abstract
Group B Streptococcus (GBS) is a major opportunistic pathogen in certain adult populations, including pregnant women, and remains a leading etiologic agent of newborn disease. During pregnancy, GBS asymptomatically colonizes the vaginal tract of 20-30% of healthy women, but can be transmitted to the neonate in utero or during birth resulting in neonatal pneumonia, sepsis, meningitis, and subsequently 10-15% mortality regardless of antibiotic treatment. While various GBS virulence factors have been implicated in vaginal colonization and invasive disease, the regulation of many of these factors remains unclear. Recently, CRISPR-associated protein-9 (Cas9), an endonuclease known for its role in CRISPR/Cas immunity, has also been observed to modulate virulence in a number of bacterial pathogens. However, the role of Cas9 in GBS colonization and disease pathogenesis has not been well-studied. We performed allelic replacement of cas9 in GBS human clinical isolates of the hypervirulent sequence-type 17 strain lineage to generate isogenic Δcas9 mutants. Compared to parental strains, Δcas9 mutants were attenuated in murine models of hematogenous meningitis and vaginal colonization and exhibited significantly decreased invasion of human brain endothelium and adherence to vaginal epithelium. To determine if Cas9 alters transcription in GBS, we performed RNA-Seq analysis and found that 353 genes (>17% of the GBS genome) were differentially expressed between the parental WT and Δcas9 mutant strain. Significantly dysregulated genes included those encoding predicted virulence factors, metabolic factors, two-component systems (TCS), and factors important for cell wall formation. These findings were confirmed by qRT-PCR and suggest that Cas9 may regulate a significant portion of the GBS genome. We studied one of the TCS regulators, CiaR, that was significantly downregulated in the Δcas9 mutant strain. RNA-Seq analysis of the WT and ΔciaR strains demonstrated that almost all CiaR-regulated genes were also significantly regulated by Cas9, suggesting that Cas9 may modulate GBS gene expression through other regulators. Further we show that CiaR contributes to GBS vaginal colonization and persistence. Altogether, these data highlight the potential complexity and importance of the non-canonical function of Cas9 in GBS colonization and disease.
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Affiliation(s)
- Brady L. Spencer
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Liwen Deng
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Kathryn A. Patras
- Department of Biology, San Diego State University, San Diego, CA, United States
| | - Zachary M. Burcham
- Department of Animal Sciences, Colorado State University, Fort Collins, CO, United States
| | - Glenda F. Sanches
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Roberto Alcântara Gomes Biology Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Prescilla E. Nagao
- Roberto Alcântara Gomes Biology Institute, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | - Kelly S. Doran
- Department of Immunology & Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
- Department of Biology, San Diego State University, San Diego, CA, United States
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Burcham ZM, Pechal JL, Schmidt CJ, Bose JL, Rosch JW, Benbow ME, Jordan HR. Bacterial Community Succession, Transmigration, and Differential Gene Transcription in a Controlled Vertebrate Decomposition Model. Front Microbiol 2019; 10:745. [PMID: 31057499 PMCID: PMC6482229 DOI: 10.3389/fmicb.2019.00745] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/25/2019] [Indexed: 01/26/2023] Open
Abstract
Decomposing remains are a nutrient-rich ecosystem undergoing constant change due to cell breakdown and abiotic fluxes, such as pH level and oxygen availability. These environmental fluxes affect bacterial communities who respond in a predictive manner associated with the time since organismal death, or the postmortem interval (PMI). Profiles of microbial taxonomic turnover and transmigration are currently being studied in decomposition ecology, and in the field of forensic microbiology as indicators of the PMI. We monitored bacterial community structural and functional changes taking place during decomposition of the intestines, bone marrow, lungs, and heart in a highly controlled murine model. We found that organs presumed to be sterile during life are colonized by Clostridium during later decomposition as the fluids from internal organs begin to emulsify within the body cavity. During colonization of previously sterile sites, gene transcripts for multiple metabolism pathways were highly abundant, while transcripts associated with stress response and dormancy increased as decomposition progressed. We found our model strengthens known bacterial taxonomic succession data after host death. This study is one of the first to provide data of expressed bacterial community genes, alongside transmigration and structural changes of microbial species during laboratory controlled vertebrate decomposition. This is an important dataset for studying the effects of the environment on bacterial communities in an effort to determine which bacterial species and which bacterial functional pathways, such as amino acid metabolism, provide key changes during stages of decomposition that relate to the PMI. Finding unique PMI species or functions can be useful for determining time since death in forensic investigations.
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Affiliation(s)
- Zachary M Burcham
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States
| | - Jennifer L Pechal
- Department of Entomology, Michigan State University, East Lansing, MI, United States
| | - Carl J Schmidt
- Department of Pathology, University of Michigan, Ann Arbor, MI, United States
| | - Jeffrey L Bose
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, United States
| | - Jason W Rosch
- Department of Infectious Disease, St. Jude Children's Research Hospital, Memphis, TN, United States
| | - M Eric Benbow
- Department of Entomology, Michigan State University, East Lansing, MI, United States.,Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, United States
| | - Heather R Jordan
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States
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Burcham ZM, Schmidt CJ, Pechal JL, Brooks CP, Rosch JW, Benbow ME, Jordan HR. Detection of critical antibiotic resistance genes through routine microbiome surveillance. PLoS One 2019; 14:e0213280. [PMID: 30870464 PMCID: PMC6417727 DOI: 10.1371/journal.pone.0213280] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 02/18/2019] [Indexed: 12/29/2022] Open
Abstract
Population-based public health data on antibiotic resistance gene carriage is poorly surveyed. Research of the human microbiome as an antibiotic resistance reservoir has primarily focused on gut associated microbial communities, but data have shown more widespread microbial colonization across organs than originally believed, with organs previously considered as sterile being colonized. Our study demonstrates the utility of postmortem microbiome sampling during routine autopsy as a method to survey antibiotic resistance carriage in a general population. Postmortem microbial sampling detected pathogens of public health concern including genes for multidrug efflux pumps, carbapenem, methicillin, vancomycin, and polymixin resistances. Results suggest that postmortem assessments of host-associated microbial communities are useful in acquiring community specific data while reducing selective-participant biases.
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Affiliation(s)
- Zachary M. Burcham
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States of America
| | - Carl J. Schmidt
- Department of Pathology, University of Michigan, Ann Arbor, MI, United States of America
| | - Jennifer L. Pechal
- Department of Entomology, Michigan State University, East Lansing, MI, United States of America
| | - Christopher P. Brooks
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States of America
| | - Jason W. Rosch
- Department of Infectious Disease, St. Jude Children’s Research Hospital, Memphis, TN, United States of America
| | - M. Eric Benbow
- Department of Entomology, Michigan State University, East Lansing, MI, United States of America
- Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, United States of America
| | - Heather R. Jordan
- Department of Biological Sciences, Mississippi State University, Starkville, MS, United States of America
- * E-mail:
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Burcham ZM, Hood JA, Pechal JL, Krausz KL, Bose JL, Schmidt CJ, Benbow ME, Jordan HR. Fluorescently labeled bacteria provide insight on post-mortem microbial transmigration. Forensic Sci Int 2016; 264:63-9. [PMID: 27032615 DOI: 10.1016/j.forsciint.2016.03.019] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 02/24/2016] [Accepted: 03/10/2016] [Indexed: 01/08/2023]
Abstract
Microbially mediated mechanisms of human decomposition begin immediately after death, and are a driving force for the conversion of a once living organism to a resource of energy and nutrients. Little is known about post-mortem microbiology in cadavers, particularly the community structure of microflora residing within the cadaver and the dynamics of these communities during decomposition. Recent work suggests these bacterial communities undergo taxa turnover and shifts in community composition throughout the post-mortem interval. In this paper we describe how the microbiome of a living host changes and transmigrates within the body after death thus linking the microbiome of a living individual to post-mortem microbiome changes. These differences in the human post-mortem from the ante-mortem microbiome have demonstrated promise as evidence in death investigations. We investigated the post-mortem structure and function dynamics of Staphylococcus aureus and Clostridium perfringens after intranasal inoculation in the animal model Mus musculus L. (mouse) to identify how transmigration of bacterial species can potentially aid in post-mortem interval estimations. S. aureus was tracked using in vivo and in vitro imaging to determine colonization routes associated with different physiological events of host decomposition, while C. perfringens was tracked using culture-based techniques. Samples were collected at discrete time intervals associated with various physiological events and host decomposition beginning at 1h and ending at 60 days post-mortem. Results suggest that S. aureus reaches its highest concentration at 5-7 days post-mortem then begins to rapidly decrease and is undetectable by culture on day 30. The ability to track these organisms as they move in to once considered sterile space may be useful for sampling during autopsy to aid in determining post-mortem interval range estimations, cause of death, and origins associated with the geographic location of human remains during death investigations.
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Affiliation(s)
- Z M Burcham
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA.
| | - J A Hood
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA.
| | - J L Pechal
- Department of Entomology, Michigan State University, East Lansing, MI, USA.
| | - K L Krausz
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA.
| | - J L Bose
- Department of Microbiology, Molecular Genetics, and Immunology, University of Kansas Medical Center, Kansas City, KS, USA.
| | - C J Schmidt
- Department of Pathology, University of Michigan, MI, USA.
| | - M E Benbow
- Department of Entomology, Michigan State University, East Lansing, MI, USA; Department of Osteopathic Medical Specialties, Michigan State University, East Lansing, MI, USA.
| | - H R Jordan
- Department of Biological Sciences, Mississippi State University, Starkville, MS, USA.
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