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Cooper AL, Low A, Wong A, Tamber S, Blais BW, Carrillo CD. Modeling the limits of detection for antimicrobial resistance genes in agri-food samples: a comparative analysis of bioinformatics tools. BMC Microbiol 2024; 24:31. [PMID: 38245666 PMCID: PMC10799530 DOI: 10.1186/s12866-023-03148-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 12/07/2023] [Indexed: 01/22/2024] Open
Abstract
BACKGROUND Although the spread of antimicrobial resistance (AMR) through food and its production poses a significant concern, there is limited research on the prevalence of AMR bacteria in various agri-food products. Sequencing technologies are increasingly being used to track the spread of AMR genes (ARGs) in bacteria, and metagenomics has the potential to bypass some of the limitations of single isolate characterization by allowing simultaneous analysis of the agri-food product microbiome and associated resistome. However, metagenomics may still be hindered by methodological biases, presence of eukaryotic DNA, and difficulties in detecting low abundance targets within an attainable sequence coverage. The goal of this study was to assess whether limits of detection of ARGs in agri-food metagenomes were influenced by sample type and bioinformatic approaches. RESULTS We simulated metagenomes containing different proportions of AMR pathogens and analysed them for taxonomic composition and ARGs using several common bioinformatic tools. Kraken2/Bracken estimates of species abundance were closest to expected values. However, analysis by both Kraken2/Bracken indicated presence of organisms not included in the synthetic metagenomes. Metaphlan3/Metaphlan4 analysis of community composition was more specific but with lower sensitivity than the Kraken2/Bracken analysis. Accurate detection of ARGs dropped drastically below 5X isolate genome coverage. However, it was sometimes possible to detect ARGs and closely related alleles at lower coverage levels if using a lower ARG-target coverage cutoff (< 80%). While KMA and CARD-RGI only predicted presence of expected ARG-targets or closely related gene-alleles, SRST2 (which allows read to map to multiple targets) falsely reported presence of distantly related ARGs at all isolate genome coverage levels. The presence of background microbiota in metagenomes influenced the accuracy of ARG detection by KMA, resulting in mcr-1 detection at 0.1X isolate coverage in the lettuce but not in the beef metagenome. CONCLUSIONS This study demonstrates accurate detection of ARGs in synthetic metagenomes using various bioinformatic methods, provided that reads from the ARG-encoding organism exceed approximately 5X isolate coverage (i.e. 0.4% of a 40 million read metagenome). While lowering thresholds for target gene detection improved sensitivity, this led to the identification of alternative ARG-alleles, potentially confounding the identification of critical ARGs in the resistome. Further advancements in sequencing technologies providing increased coverage depth or extended read lengths may improve ARG detection in agri-food metagenomic samples, enabling use of this approach for tracking clinically important ARGs in agri-food samples.
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Affiliation(s)
- Ashley L Cooper
- Research and Development, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, ON, Canada
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Andrew Low
- Research and Development, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, ON, Canada
| | - Alex Wong
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Sandeep Tamber
- Microbiology Research Division, Bureau of Microbial Hazards, Health Canada, Ottawa, ON, Canada
| | - Burton W Blais
- Research and Development, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, ON, Canada
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Catherine D Carrillo
- Research and Development, Ottawa Laboratory (Carling), Canadian Food Inspection Agency, Ottawa, ON, Canada.
- Department of Biology, Carleton University, Ottawa, ON, Canada.
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Hem S, Cummins ML, Wyrsch ER, Drigo B, Hoye BJ, Maute K, Sanderson-Smith M, Gorman J, Bogema DR, Jenkins C, Deutscher AT, Yam J, Hai F, Donner E, Jarocki VM, Djordjevic SP. Genomic analysis of Citrobacter from Australian wastewater and silver gulls reveals novel sequence types carrying critically important antibiotic resistance genes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 909:168608. [PMID: 37977387 DOI: 10.1016/j.scitotenv.2023.168608] [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: 08/17/2023] [Revised: 11/08/2023] [Accepted: 11/14/2023] [Indexed: 11/19/2023]
Abstract
Antimicrobial resistance (AMR) is a major public health concern, and environmental bacteria have been recognized as important reservoirs of antimicrobial resistance genes (ARGs). Citrobacter, a common environmental bacterium and opportunistic pathogen in humans and other animals, has been largely understudied in terms of its diversity and AMR potential. Whole-genome (short-read) sequencing on a total of 77 Citrobacter isolates obtained from Australian silver gull (Chroicocephalus novaehollandiae) (n = 17) and influent wastewater samples (n = 60) was performed, revealing a diverse Citrobacter population, with seven different species and 33 sequence types, 17 of which were novel. From silver gull using non-selective media we isolated a broader range of species with little to no mobilised ARG carriage. Wastewater isolates (selected using Carbapenem- Resistant Enterobacterales (CRE) selective media) carried a heavy burden of ARGs (up to 21 ARGs, conferring resistance to nine classes of antibiotics), with several novel multidrug-resistant (MDR) lineages identified, including C. braakii ST1110, which carried ARGs conferring resistance to eight to nine classes of antibiotics, and C. freundii ST1105, which carried two carbapenemase genes, blaIMP-4 in class 1 integron structure, and blaKPC-2. Additionally, we identified an MDR C. portucalensis isolate carrying blaNDM-1, blaSHV-12, and mcr-9. We identified IncC, IncM2, and IncP6 plasmids as the likely vectors for many of the critically important mobilised ARGs. Phylogenetic analyses were performed to assess any epidemiological linkages between isolation sources, demonstrating low relatedness across sources beyond the ST level. However, these analyses did reveal some closer relationships between strains from disparate wastewater sources despite their collection some 13,000 km apart. These findings support the need for future surveillance of Citrobacter populations in wastewater and wildlife populations to monitor for potential opportunistic human pathogens.
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Affiliation(s)
- Sopheak Hem
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Max L Cummins
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Ethan R Wyrsch
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia
| | - Barbara Drigo
- UniSA STEM, University of South Australia, Adelaide, SA, Australia
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, University of Wollongong NSW, Australia; Environmental Futures Research Centre, University of Wollongong NSW, Australia
| | - Kimberly Maute
- School of Earth, Atmospheric and Life Sciences, University of Wollongong NSW, Australia; Environmental Futures Research Centre, University of Wollongong NSW, Australia
| | - Martina Sanderson-Smith
- School of Chemistry and Molecular Bioscience and Molecular Horizons, University of Wollongong, NSW, Australia
| | - Jody Gorman
- School of Chemistry and Molecular Bioscience and Molecular Horizons, University of Wollongong, NSW, Australia
| | - Daniel R Bogema
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Cheryl Jenkins
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Ania T Deutscher
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Jerald Yam
- Elizabeth Macarthur Agricultural Institute, NSW Department of Primary Industries, Menangle, NSW, Australia
| | - Faisal Hai
- School of Civil, Mining, Environmental and Architectural Engineering, University of Wollongong, NSW, Australia
| | - Erica Donner
- Cooperative Research Centre for Solving Antimicrobial resistance in Agribusiness, Food, and Environments (CRC SAAFE), Adelaide, South Australia, Australia; Future Industries Institute, University of South Australia, Adelaide, South Australia, Australia
| | - Veronica M Jarocki
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia.
| | - Steven P Djordjevic
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Ultimo, Australia; The Australian Centre for Genomic Epidemiological Microbiology, University of Technology Sydney, Ultimo, Australia.
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Pilar AVC, Petronella N, Dussault FM, Verster AJ, Bekal S, Levesque RC, Goodridge L, Tamber S. Similar yet different: phylogenomic analysis to delineate Salmonella and Citrobacter species boundaries. BMC Genomics 2020; 21:377. [PMID: 32471418 PMCID: PMC7257147 DOI: 10.1186/s12864-020-06780-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 05/13/2020] [Indexed: 12/14/2022] Open
Abstract
Background Salmonella enterica is a leading cause of foodborne illness worldwide resulting in considerable public health and economic costs. Testing for the presence of this pathogen in food is often hampered by the presence of background microflora that may present as Salmonella (false positives). False positive isolates belonging to the genus Citrobacter can be difficult to distinguish from Salmonella due to similarities in their genetics, cell surface antigens, and other phenotypes. In order to understand the genetic basis of these similarities, a comparative genomic approach was used to define the pan-, core, accessory, and unique coding sequences of a representative population of Salmonella and Citrobacter strains. Results Analysis of the genomic content of 58 S. enterica strains and 37 Citrobacter strains revealed the presence of 31,130 and 1540 coding sequences within the pan- and core genome of this population. Amino acid sequences unique to either Salmonella (n = 1112) or Citrobacter (n = 195) were identified and revealed potential niche-specific adaptations. Phylogenetic network analysis of the protein families encoded by the pan-genome indicated that genetic exchange between Salmonella and Citrobacter may have led to the acquisition of similar traits and also diversification within the genera. Conclusions Core genome analysis suggests that the Salmonella enterica and Citrobacter populations investigated here share a common evolutionary history. Comparative analysis of the core and pan-genomes was able to define the genetic features that distinguish Salmonella from Citrobacter and highlight niche specific adaptations.
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Affiliation(s)
| | - Nicholas Petronella
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Forest M Dussault
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Adrian J Verster
- Bureau of Food Surveillance and Science Integration, Health Canada, Ottawa, Ontario, Canada
| | - Sadjia Bekal
- Laboratoire de santé publique du Québec, Ste-Anne-de-Bellevue, Quebec, Canada
| | - Roger C Levesque
- Institute for Integrative and Systems Biology (IBIS), Université Laval, Quebec, Quebec, Canada
| | - Lawrence Goodridge
- Department of Food Science and Agricultural Chemistry, Faculty of Agricultural and Environmental Sciences, McGill University, Ste-Anne-de-Bellevue, Quebec, Canada.,Food Science Department, University of Guelph, Guelph, Ontario, Canada
| | - Sandeep Tamber
- Bureau of Microbial Hazards, Health Canada, Ottawa, Ontario, Canada.
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Isolation and molecular characterization of citrobacter species in fruits and vegetables sold for consumption in ILE-IFE, Nigeria. SCIENTIFIC AFRICAN 2019. [DOI: 10.1016/j.sciaf.2019.e00173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Murer L, Didoné S, Freitas A, Lovato M. Investigação de Salmonella spp. em Psittaciformes exóticos e nativos mantidos em cativeiro na região central do Rio Grande do Sul. ARQ BRAS MED VET ZOO 2018. [DOI: 10.1590/1678-4162-9794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
RESUMO As doenças infecciosas são reconhecidamente causadoras de declínios populacionais de animais silvestres e algumas delas podem representar ameaça à saúde pública. O presente estudo objetivou investigar a ocorrência de Salmonella spp. em Psittaciformes exóticos e nativos mantidos em cativeiro na região central do Rio Grande do Sul, além de comparar os resultados obtidos por meio do método bacteriológico convencional e da reação em cadeia da polimerase (PCR), mediante a utilização de material fecal do ambiente, evitando-se o estresse da contenção. Durante os meses de agosto/2016 e setembro/2016 foram coletadas amostras de fezes frescas de 90 gaiolas em dois criatórios, representando 180 aves. Com as duas técnicas empregadas nas análises, as amostras foram negativas para Salmonella spp., contudo foram detectadas bactérias da família Enterobacteriaceae: Escherichia coli, Cedecea sp. e Citrobacter freundii. Considera-se importante a continuidade do monitoramento dos criatórios, já que o patógeno investigado pode estar em aves portadoras e se manifestar em situações de estresse, representando riscos enquanto zoonose e prejuízos à saúde das aves.
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Affiliation(s)
- L. Murer
- Universidade Federal de Santa Maria, Brazil
| | | | | | - M. Lovato
- Universidade Federal de Santa Maria, Brazil
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Molecular characterization and antimicrobial resistance profile of atypical Citrobacter gillenii and Citrobacter sp. isolated from diseased rainbow trout ( Oncorhynchus mykiss ). J Glob Antimicrob Resist 2017; 10:136-142. [DOI: 10.1016/j.jgar.2017.05.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 10/19/2022] Open
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Valdivia-Anistro JA, Eguiarte-Fruns LE, Delgado-Sapién G, Márquez-Zacarías P, Gasca-Pineda J, Learned J, Elser JJ, Olmedo-Alvarez G, Souza V. Variability of rRNA Operon Copy Number and Growth Rate Dynamics of Bacillus Isolated from an Extremely Oligotrophic Aquatic Ecosystem. Front Microbiol 2016; 6:1486. [PMID: 26779143 PMCID: PMC4700252 DOI: 10.3389/fmicb.2015.01486] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 12/09/2015] [Indexed: 12/28/2022] Open
Abstract
The ribosomal RNA (rrn) operon is a key suite of genes related to the production of protein synthesis machinery and thus to bacterial growth physiology. Experimental evidence has suggested an intrinsic relationship between the number of copies of this operon and environmental resource availability, especially the availability of phosphorus (P), because bacteria that live in oligotrophic ecosystems usually have few rrn operons and a slow growth rate. The Cuatro Ciénegas Basin (CCB) is a complex aquatic ecosystem that contains an unusually high microbial diversity that is able to persist under highly oligotrophic conditions. These environmental conditions impose a variety of strong selective pressures that shape the genome dynamics of their inhabitants. The genus Bacillus is one of the most abundant cultivable bacterial groups in the CCB and usually possesses a relatively large number of rrn operon copies (6–15 copies). The main goal of this study was to analyze the variation in the number of rrn operon copies of Bacillus in the CCB and to assess their growth-related properties as well as their stoichiometric balance (N and P content). We defined 18 phylogenetic groups within the Bacilli clade and documented a range of from six to 14 copies of the rrn operon. The growth dynamic of these Bacilli was heterogeneous and did not show a direct relation to the number of operon copies. Physiologically, our results were not consistent with the Growth Rate Hypothesis, since the copies of the rrn operon were decoupled from growth rate. However, we speculate that the diversity of the growth properties of these Bacilli as well as the low P content of their cells in an ample range of rrn copy number is an adaptive response to oligotrophy of the CCB and could represent an ecological mechanism that allows these taxa to coexist. These findings increase the knowledge of the variability in the number of copies of the rrn operon in the genus Bacillus and give insights about the physiology of this bacterial group under extreme oligotrophic conditions.
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Affiliation(s)
- Jorge A Valdivia-Anistro
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Luis E Eguiarte-Fruns
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Gabriela Delgado-Sapién
- Laboratorio de Genómica Bacteriana, Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | | | - Jaime Gasca-Pineda
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
| | - Jennifer Learned
- School of Life Sciences, Arizona State University, Tempe AZ, USA
| | - James J Elser
- School of Life Sciences, Arizona State University, Tempe AZ, USA
| | - Gabriela Olmedo-Alvarez
- Laboratorio de Bacteriología Molecular, Departamento de Ingeniería Genética, CINVESTAV - Unidad Irapuato Irapuato, Mexico
| | - Valeria Souza
- Laboratorio de Evolución Molecular y Experimental, Departamento de Ecología Evolutiva, Instituto de Ecología, Universidad Nacional Autónoma de México Coyoacán, Mexico
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Kolínská R, Spanělová P, Dřevínek M, Hrabák J, Zemličková H. Species identification of strains belonging to genus Citrobacter using the biochemical method and MALDI-TOF mass spectrometry. Folia Microbiol (Praha) 2014; 60:53-9. [PMID: 25113540 DOI: 10.1007/s12223-014-0340-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 07/18/2014] [Indexed: 01/20/2023]
Abstract
Strains of genus Citrobacter (152 isolates from 1950 to 1988 deposited in the Czech National Collection of Type Cultures, Prague) were re-classified using biological and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) methods. One-hundred thirty-six strains (ca. 90 %) were identified to the species level using the biological method with evaluation by Farmer matrix. MALDI-TOF MS exhibited better identification capability, the data being more compact; the method was unambiguously successful in typing 145 (95 %) strains. Comparison of the results of identification by the two methods revealed differences (for 12 samples) in identified species which, considering all biochemical and/or MS characteristics, could be attributed to the natural variability of strains and close relation of the misidentified species (all of them belonged to the Citrobacter freundii complex). Taking into account all the above data, both methods can be considered reliable; however, the MALDI-TOF MS exhibits higher accuracy, efficiency, and rapidity.
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Affiliation(s)
- Renáta Kolínská
- National Institute of Public Health, Šrobárova 48, 100 42, Prague 10, Czech Republic,
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