Interspecies transfer of Vancomycin, Erythromycin and Tetracycline resistance among Enterococcus species recovered from agrarian sources

Michael Conwell, Victoria Daniels, Patrick Naughton, James Dooley

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Background: Enterococci are now well recognised for their ability to transfer antibiotic resistance and for their association with nosocomial infections, but less is known regarding their relevance in the wider environment. Enterococcus faecalis and Enterococcus faecium were isolated from a range of agrarian associated sources (low-flow water, septic tank, poultry litter, high flow water, slurry/soil) and were assessed for latent ability to transfer antimicrobial resistance. Results: The isolates were tested for phenotypic clumping in the presence of cell-free supernatant from other isolates. Some isolates were identified which demonstrated clumping, indicating that they possessed peptide sex pheromone conjugal machinery. All isolates were also tested for antibiotic resistance phenotypes using both disc diffusion and minimum inhibitory concentration (MIC) assays. These tests revealed that the enterococci demonstrated both phenotypic clumping and antibiotic resistance phenotypes. Based on these selection criteria, the isolates were identified as having the potential for horizontal gene transfer and were used to investigate the transfer of multiple antibiotic resistance phenotypes. Conjugal transfer of antibiotic resistance phenotypes was determined using a solid agar mating method followed by a standard antibiotic selection test resulting in different transfer patterns. An interspecies conjugal transfer of vancomycin resistance from E. faecalis to E. faecium was identified while the remaining reactions were within the same species. Transfer efficiencies ranging from 2x10-1 to 2.3x10-5 were determined based on the reactions of three donor isolates (MF06036, MF0410 and MF06035) and two recipient isolates (MW01105Rif and ST01109Rif), with the transfer of vancomycin, erythromycin and tetracycline resistance genes. Conclusions: The conjugation reactions and selection conditions used in this study resulted in a variety of co-transferred resistance phenotypes suggesting the presence of different mobile elements in the set of natural isolates. This study highlights the potential for extensive horizontal gene transfer in a previously neglected reservoir for enterococci.
LanguageEnglish
Number of pages8
JournalBMC Microbiology
Volume17
Issue number19
DOIs
Publication statusPublished - 18 Jan 2017

Fingerprint

Vancomycin Resistance
Tetracycline Resistance
Enterococcus
Erythromycin
Microbial Drug Resistance
Phenotype
Horizontal Gene Transfer
Enterococcus faecium
Enterococcus faecalis
Sex Attractants
Water
Microbial Sensitivity Tests
Poultry
Cross Infection
Patient Selection
Agar
Soil
Anti-Bacterial Agents
Peptides
Genes

Keywords

  • Enterococci – Water – Conjugation – Vancomycin resistance – Erythromycin resistance – Tetracycline resistance

Cite this

@article{44aa9a5f10a14c9aa6c803e97f607a22,
title = "Interspecies transfer of Vancomycin, Erythromycin and Tetracycline resistance among Enterococcus species recovered from agrarian sources",
abstract = "Background: Enterococci are now well recognised for their ability to transfer antibiotic resistance and for their association with nosocomial infections, but less is known regarding their relevance in the wider environment. Enterococcus faecalis and Enterococcus faecium were isolated from a range of agrarian associated sources (low-flow water, septic tank, poultry litter, high flow water, slurry/soil) and were assessed for latent ability to transfer antimicrobial resistance. Results: The isolates were tested for phenotypic clumping in the presence of cell-free supernatant from other isolates. Some isolates were identified which demonstrated clumping, indicating that they possessed peptide sex pheromone conjugal machinery. All isolates were also tested for antibiotic resistance phenotypes using both disc diffusion and minimum inhibitory concentration (MIC) assays. These tests revealed that the enterococci demonstrated both phenotypic clumping and antibiotic resistance phenotypes. Based on these selection criteria, the isolates were identified as having the potential for horizontal gene transfer and were used to investigate the transfer of multiple antibiotic resistance phenotypes. Conjugal transfer of antibiotic resistance phenotypes was determined using a solid agar mating method followed by a standard antibiotic selection test resulting in different transfer patterns. An interspecies conjugal transfer of vancomycin resistance from E. faecalis to E. faecium was identified while the remaining reactions were within the same species. Transfer efficiencies ranging from 2x10-1 to 2.3x10-5 were determined based on the reactions of three donor isolates (MF06036, MF0410 and MF06035) and two recipient isolates (MW01105Rif and ST01109Rif), with the transfer of vancomycin, erythromycin and tetracycline resistance genes. Conclusions: The conjugation reactions and selection conditions used in this study resulted in a variety of co-transferred resistance phenotypes suggesting the presence of different mobile elements in the set of natural isolates. This study highlights the potential for extensive horizontal gene transfer in a previously neglected reservoir for enterococci.",
keywords = "Enterococci – Water – Conjugation – Vancomycin resistance – Erythromycin resistance – Tetracycline resistance",
author = "Michael Conwell and Victoria Daniels and Patrick Naughton and James Dooley",
note = "Compliant in UIR; evidence uploaded to 'Other files'. Also Open Access article (evidence also uploaded to 'Other files'). Reference text: References 1.Van Tyne D, Gilmore MS. Friend turned foe: evolution of enterococcal virulence and antibiotic resistance. Ann Rev Microbiol. 2014;68:337–56. doi:10.1146/annurev-micro-091213-113003. View ArticleGoogle Scholar 2.Domig KJ, Mayer HK, Kneifel W. Methods used for the isolation, enumeration, characterisation and identification of Enterococcus spp. 2. Pheno- and genotypic criteria. Int J Food Microbiol. 2003;88:165–88. View ArticlePubMedGoogle Scholar 3.Byappanahalli MN, Nevers MB, Korajkic A, Staley ZR, Harwood VJ. Enterococci in the environment. Microbiol Mol Biol Rev. 2012;76:685–706. doi:10.1128/MMBR.00023-12. View ArticlePubMedPubMed CentralGoogle Scholar 4.Aarestrup FM, McNicholas PM. Incidence of high-level evernimicin resistance in Enterococcus faecium among food animals and humans. Antimicrob Agents Chemother. 2002;46:3088–90. View ArticlePubMedPubMed CentralGoogle Scholar 5.Cabelli VJ. Health effects criteria for marine recreational waters. Research Triangle Park: U.S. Environmental Protection Agency; 1983. Google Scholar 6.Di Cesare A, Pasquaroli S, Vignaroli C, Paroncini P, Luna GM, Manso E, Biavasco F. The marine environment as a reservoir of enterococci carrying resistance and virulence genes strongly associated with clinical strains. Environ Microbiol Rep. 2014;6:184–90. doi:10.1111/1758-2229.12125. View ArticlePubMedGoogle Scholar 7.EPA 2012. Integrated water quality report Monaghan and Louth: Antimicrobials in agriculture and the environment: reducing unnecessary use and waste. http://www.epa.ie/pubs/reports/water/waterqua/iwqmolou/IWQ_2012_Monaghan_Louth.pdf. Accessed 20 June 2016. 8.Review on Antimicrobial Resistance Report 2015 ‘Antimicrobials in agriculture and the environment: reducing unnecessary use and waste. Wellcome Trust. https://amr-review.org/sites/default/files/Antimicrobials{\%}20in{\%}20agriculture{\%}20and{\%}20the{\%}20environment{\%}20-{\%}20Reducing{\%}20unnecessary{\%}20use{\%}20and{\%}20waste.pdf. Accessed 20 June 2016. 9.Gilmore MS, Lebreton F, van Schaik W. Genomic transition of enterococci from gut commensals to leading causes of multidrug-resistant hospital infection in the antibiotic era. Curr Opin Microbiol. 2013;16:10–6. doi:10.1016/j.mib.2013.01.006. View ArticlePubMedPubMed CentralGoogle Scholar 10.Clewell DB. Movable genetic elements and antibiotic resistance in enterococci. Eur J Clin Microbiol Infect Dis. 1990;9:90–102. View ArticlePubMedGoogle Scholar 11.Manson JM, Hancock LE, Gilmore MS. Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits. Proc Natl Acad Sci U S A. 2010;107:12269–74. doi:10.1073/pnas.1000139107. View ArticlePubMedPubMed CentralGoogle Scholar 12.Guzman Prieto AM, van Schaik W, Rogers MR, Coque TM, Baquero F, Corander J, Willems RJ. Global emergence and dissemination of enterococci as nosocomial pathogens: attack of the clones? Front Microbiol. 2016;7:788. doi:10.3389/fmicb.2016.00788. View ArticlePubMedPubMed CentralGoogle Scholar 13.Cafini F, le Nguyen TT, Higashide M, Rom{\'a}n F, Prieto J, Morikawa K. Horizontal gene transmission of the cfr gene to MRSA and Enterococcus: role of Staphylococcus epidermidis as a reservoir and alternative pathway for the spread of linezolid resistance. J Antimicrob Chemother. 2016;71:587–92. doi:10.1093/jac/dkv391. View ArticlePubMedGoogle Scholar 14.Daniels V. PhD Thesis: antibiotic resistant bacteria in Irish waters: molecular epidemiology and hydrological control. University of Ulster; 2011. Retrieved from http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551508. Assessed 20 June 2016. 15.K{\"u}hn I, Iversen A, Burman LG, Olsson-Liljequist B, Franklin A, Finn M, Aarestrup F, Seyfarth AM, Blanch AR, Taylor H, Caplin J, Moreno MA, Dominguez L, M{\"o}llby R. Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment. Example of an ongoing project within the European research programme. Int J Antimicrob Agents. 2000;14:337–42. View ArticlePubMedGoogle Scholar 16.Ahmed W, Neller R, Katouli M. Host species-specific metabolic fingerprint database for enterococci and Escherichia coli and its application to identify sources of fecal contamination in surface waters. Appl Environ Microbiol. 2005;71:4461–8. View ArticlePubMedPubMed CentralGoogle Scholar 17.European Committee on Antimicrobial Susceptibility Testing. Data from the EUCAST MIC distribution website. https://mic.eucast.org/Eucast2/. Accessed 27 Sept 2016. 18.Wiegand I, Hilpert K, Hancock RE. Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances. Nat Protoc. 2008;3:163–75. doi:10.1038/nprot.2007.521. View ArticlePubMedGoogle Scholar 19.Jahan M, Krause DO, Holley RA. Antimicrobial resistance of Enterococcus species from meat and fermented meat products isolated by a PCR-based rapid screening method. Int J Food Microbiol. 2013;15:89–95. doi:10.1016/j.ijfoodmicro.2013.02.017. View ArticleGoogle Scholar 20.Cook L, Barnes A, Dunny G. Biofilm growth alters regulation of conjugation by a bacterial pheromone. Mol Microbiol. 2011;81(6):1499–510. View ArticlePubMedPubMed CentralGoogle Scholar 21.Tsuchizaki N, Ishikawa J, Hotta K. Colony PCR for rapid detection of antibiotic resistance genes in MRSA and enterococci. Jpn J Antibiot. 2000;53:422–9. View ArticlePubMedGoogle Scholar 22.Palmer KL, Kos VN, Gilmore MS. Horizontal gene transfer and the genomics of enterococcal antibiotic resistance. Curr Opin Microbiol. 2010;13:632–9. doi:10.1016/j.mib.2010.08.004. View ArticlePubMedPubMed CentralGoogle Scholar 23.Dunny GM. Enterococcal sex pheromones: signaling, social behavior, and evolution. Ann Rev Genet. 2013;47:457–82. doi:10.1146/annurev-genet-111212-133449. View ArticlePubMedGoogle Scholar 24.Enne VI, Delsol AA, Roe JM, Bennett PM. Rifampicin resistance and its fitness cost in Enterococcus faecium. J Antimicrob Chemother. 2004;53:203–7. View ArticlePubMedGoogle Scholar 25.Courvalin P. Vancomycin resistance in gram-positive cocci. Clin Infect Dis. 2006;42 Suppl 1:S25–34. View ArticlePubMedGoogle Scholar 26.Donabedian SM, Thal LA, Hershberger E, Perri MB, Chow JW, Bartlett P, Jones R, Joyce K, Rossiter S, Gay K, Johnson J, Mackinson C, Debess E, Madden J, Angulo F, Zervos MJ. Molecular characterization of gentamicin-resistant Enterococci in the United States: evidence of spread from animals to humans through food. J Clin Microbiol. 2003;41:1109–13. View ArticlePubMedPubMed CentralGoogle Scholar 27.Vignaroli C, Zandri G, Aquilanti L, Pasquaroli S, Biavasco F. Multidrug-resistant enterococci in animal meat and faeces and co-transfer of resistance from an Enterococcus durans to a human Enterococcus faecium. Curr Microbiol. 2011;62:1438–47. doi:10.1007/s00284-011-9880-x. View ArticlePubMedGoogle Scholar 28.Werner G, Coque TM, Franz CM, Grohmann E, Hegstad K, Jensen L, van Schaik W, Weaver K. Antibiotic resistant enterococci-tales of a drug resistance gene trafficker. Int J Med Microbiol. 2013;303:360–79. doi:10.1016/j.ijmm.2013.03.001. View ArticlePubMedGoogle Scholar 29.Huys G, D’Haene K, Collard JM, Swings J. Prevalence and molecular characterization of tetracycline resistance in Enterococcus isolates from food. Appl Environ Microbiol. 2004;70:1555–62. View ArticlePubMedPubMed CentralGoogle Scholar 30.Moubareck C, Bourgeois N, Courvalin P, Doucet-Populaire F. Multiple antibiotic resistance gene transfers from animal to human enterococci in the digestive tract of gnotobiotic mice. Antimicrob Agents Chemother. 2003;47:2993–6. View ArticlePubMedPubMed CentralGoogle Scholar 31.Aarestrup FM, Agerso Y, Gerner-Smidt P, Madsen M, Jensen LB. Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers, and pigs in Denmark. Diagn Microbiol Infect Dis. 2000;37:127–37. View ArticlePubMedGoogle Scholar 32.Trzcinski K, Cooper BS, Hryniewicz W, Dowson CG. Expression of resistance to tetracyclines in strains of methicillin-resistant Staphylococcus aureus. J Antimicrob Chemother. 2000;45:763–70. View ArticlePubMedGoogle Scholar 33.Choi JM, Woo GJ. Transfer of tetracycline resistance genes with aggregation substance in food-borne Enterococcus faecalis. Curr Microbiol. 2015;70:476–84. doi:10.1007/s00284-014-0742-1. View ArticlePubMedGoogle Scholar 34.Aminov RI, Garrigues-Jeanjean N, Mackie RI. Molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins. Appl Environ Microbiol. 2001;67:22–32. View ArticlePubMedPubMed CentralGoogle Scholar 35.Leclercq R, Dutka-Malen S, Brisson-No{\"e}l A, Molinas C, Derlot E, Arthur M, Duval J, Courvalin P. Resistance of enterococci to aminoglycosides and glycopeptides. Clin Infect Dis. 1992;15:495–501. doi:10.1093/clind/15.3.495. View ArticlePubMedGoogle Scholar",
year = "2017",
month = "1",
day = "18",
doi = "10.1186/s12866-017-0928-3",
language = "English",
volume = "17",
journal = "BMC Microbiology",
issn = "1471-2180",
publisher = "BioMed Central",
number = "19",

}

Interspecies transfer of Vancomycin, Erythromycin and Tetracycline resistance among Enterococcus species recovered from agrarian sources. / Conwell, Michael; Daniels, Victoria; Naughton, Patrick; Dooley, James.

In: BMC Microbiology, Vol. 17, No. 19, 18.01.2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Interspecies transfer of Vancomycin, Erythromycin and Tetracycline resistance among Enterococcus species recovered from agrarian sources

AU - Conwell, Michael

AU - Daniels, Victoria

AU - Naughton, Patrick

AU - Dooley, James

N1 - Compliant in UIR; evidence uploaded to 'Other files'. Also Open Access article (evidence also uploaded to 'Other files'). Reference text: References 1.Van Tyne D, Gilmore MS. Friend turned foe: evolution of enterococcal virulence and antibiotic resistance. Ann Rev Microbiol. 2014;68:337–56. doi:10.1146/annurev-micro-091213-113003. View ArticleGoogle Scholar 2.Domig KJ, Mayer HK, Kneifel W. Methods used for the isolation, enumeration, characterisation and identification of Enterococcus spp. 2. Pheno- and genotypic criteria. Int J Food Microbiol. 2003;88:165–88. View ArticlePubMedGoogle Scholar 3.Byappanahalli MN, Nevers MB, Korajkic A, Staley ZR, Harwood VJ. Enterococci in the environment. Microbiol Mol Biol Rev. 2012;76:685–706. doi:10.1128/MMBR.00023-12. View ArticlePubMedPubMed CentralGoogle Scholar 4.Aarestrup FM, McNicholas PM. Incidence of high-level evernimicin resistance in Enterococcus faecium among food animals and humans. Antimicrob Agents Chemother. 2002;46:3088–90. View ArticlePubMedPubMed CentralGoogle Scholar 5.Cabelli VJ. Health effects criteria for marine recreational waters. Research Triangle Park: U.S. Environmental Protection Agency; 1983. Google Scholar 6.Di Cesare A, Pasquaroli S, Vignaroli C, Paroncini P, Luna GM, Manso E, Biavasco F. The marine environment as a reservoir of enterococci carrying resistance and virulence genes strongly associated with clinical strains. Environ Microbiol Rep. 2014;6:184–90. doi:10.1111/1758-2229.12125. View ArticlePubMedGoogle Scholar 7.EPA 2012. Integrated water quality report Monaghan and Louth: Antimicrobials in agriculture and the environment: reducing unnecessary use and waste. http://www.epa.ie/pubs/reports/water/waterqua/iwqmolou/IWQ_2012_Monaghan_Louth.pdf. Accessed 20 June 2016. 8.Review on Antimicrobial Resistance Report 2015 ‘Antimicrobials in agriculture and the environment: reducing unnecessary use and waste. Wellcome Trust. https://amr-review.org/sites/default/files/Antimicrobials%20in%20agriculture%20and%20the%20environment%20-%20Reducing%20unnecessary%20use%20and%20waste.pdf. Accessed 20 June 2016. 9.Gilmore MS, Lebreton F, van Schaik W. Genomic transition of enterococci from gut commensals to leading causes of multidrug-resistant hospital infection in the antibiotic era. Curr Opin Microbiol. 2013;16:10–6. doi:10.1016/j.mib.2013.01.006. View ArticlePubMedPubMed CentralGoogle Scholar 10.Clewell DB. Movable genetic elements and antibiotic resistance in enterococci. Eur J Clin Microbiol Infect Dis. 1990;9:90–102. View ArticlePubMedGoogle Scholar 11.Manson JM, Hancock LE, Gilmore MS. Mechanism of chromosomal transfer of Enterococcus faecalis pathogenicity island, capsule, antimicrobial resistance, and other traits. Proc Natl Acad Sci U S A. 2010;107:12269–74. doi:10.1073/pnas.1000139107. View ArticlePubMedPubMed CentralGoogle Scholar 12.Guzman Prieto AM, van Schaik W, Rogers MR, Coque TM, Baquero F, Corander J, Willems RJ. Global emergence and dissemination of enterococci as nosocomial pathogens: attack of the clones? Front Microbiol. 2016;7:788. doi:10.3389/fmicb.2016.00788. View ArticlePubMedPubMed CentralGoogle Scholar 13.Cafini F, le Nguyen TT, Higashide M, Román F, Prieto J, Morikawa K. Horizontal gene transmission of the cfr gene to MRSA and Enterococcus: role of Staphylococcus epidermidis as a reservoir and alternative pathway for the spread of linezolid resistance. J Antimicrob Chemother. 2016;71:587–92. doi:10.1093/jac/dkv391. View ArticlePubMedGoogle Scholar 14.Daniels V. PhD Thesis: antibiotic resistant bacteria in Irish waters: molecular epidemiology and hydrological control. University of Ulster; 2011. Retrieved from http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.551508. Assessed 20 June 2016. 15.Kühn I, Iversen A, Burman LG, Olsson-Liljequist B, Franklin A, Finn M, Aarestrup F, Seyfarth AM, Blanch AR, Taylor H, Caplin J, Moreno MA, Dominguez L, Möllby R. Epidemiology and ecology of enterococci, with special reference to antibiotic resistant strains, in animals, humans and the environment. Example of an ongoing project within the European research programme. Int J Antimicrob Agents. 2000;14:337–42. View ArticlePubMedGoogle Scholar 16.Ahmed W, Neller R, Katouli M. Host species-specific metabolic fingerprint database for enterococci and Escherichia coli and its application to identify sources of fecal contamination in surface waters. Appl Environ Microbiol. 2005;71:4461–8. View ArticlePubMedPubMed CentralGoogle Scholar 17.European Committee on Antimicrobial Susceptibility Testing. Data from the EUCAST MIC distribution website. https://mic.eucast.org/Eucast2/. Accessed 27 Sept 2016. 18.Wiegand I, Hilpert K, Hancock RE. Agar and broth dilution methods to determine the minimal inhibitory concentration (MIC) of antimicrobial substances. Nat Protoc. 2008;3:163–75. doi:10.1038/nprot.2007.521. View ArticlePubMedGoogle Scholar 19.Jahan M, Krause DO, Holley RA. Antimicrobial resistance of Enterococcus species from meat and fermented meat products isolated by a PCR-based rapid screening method. Int J Food Microbiol. 2013;15:89–95. doi:10.1016/j.ijfoodmicro.2013.02.017. View ArticleGoogle Scholar 20.Cook L, Barnes A, Dunny G. Biofilm growth alters regulation of conjugation by a bacterial pheromone. Mol Microbiol. 2011;81(6):1499–510. View ArticlePubMedPubMed CentralGoogle Scholar 21.Tsuchizaki N, Ishikawa J, Hotta K. Colony PCR for rapid detection of antibiotic resistance genes in MRSA and enterococci. Jpn J Antibiot. 2000;53:422–9. View ArticlePubMedGoogle Scholar 22.Palmer KL, Kos VN, Gilmore MS. Horizontal gene transfer and the genomics of enterococcal antibiotic resistance. Curr Opin Microbiol. 2010;13:632–9. doi:10.1016/j.mib.2010.08.004. View ArticlePubMedPubMed CentralGoogle Scholar 23.Dunny GM. Enterococcal sex pheromones: signaling, social behavior, and evolution. Ann Rev Genet. 2013;47:457–82. doi:10.1146/annurev-genet-111212-133449. View ArticlePubMedGoogle Scholar 24.Enne VI, Delsol AA, Roe JM, Bennett PM. Rifampicin resistance and its fitness cost in Enterococcus faecium. J Antimicrob Chemother. 2004;53:203–7. View ArticlePubMedGoogle Scholar 25.Courvalin P. Vancomycin resistance in gram-positive cocci. Clin Infect Dis. 2006;42 Suppl 1:S25–34. View ArticlePubMedGoogle Scholar 26.Donabedian SM, Thal LA, Hershberger E, Perri MB, Chow JW, Bartlett P, Jones R, Joyce K, Rossiter S, Gay K, Johnson J, Mackinson C, Debess E, Madden J, Angulo F, Zervos MJ. Molecular characterization of gentamicin-resistant Enterococci in the United States: evidence of spread from animals to humans through food. J Clin Microbiol. 2003;41:1109–13. View ArticlePubMedPubMed CentralGoogle Scholar 27.Vignaroli C, Zandri G, Aquilanti L, Pasquaroli S, Biavasco F. Multidrug-resistant enterococci in animal meat and faeces and co-transfer of resistance from an Enterococcus durans to a human Enterococcus faecium. Curr Microbiol. 2011;62:1438–47. doi:10.1007/s00284-011-9880-x. View ArticlePubMedGoogle Scholar 28.Werner G, Coque TM, Franz CM, Grohmann E, Hegstad K, Jensen L, van Schaik W, Weaver K. Antibiotic resistant enterococci-tales of a drug resistance gene trafficker. Int J Med Microbiol. 2013;303:360–79. doi:10.1016/j.ijmm.2013.03.001. View ArticlePubMedGoogle Scholar 29.Huys G, D’Haene K, Collard JM, Swings J. Prevalence and molecular characterization of tetracycline resistance in Enterococcus isolates from food. Appl Environ Microbiol. 2004;70:1555–62. View ArticlePubMedPubMed CentralGoogle Scholar 30.Moubareck C, Bourgeois N, Courvalin P, Doucet-Populaire F. Multiple antibiotic resistance gene transfers from animal to human enterococci in the digestive tract of gnotobiotic mice. Antimicrob Agents Chemother. 2003;47:2993–6. View ArticlePubMedPubMed CentralGoogle Scholar 31.Aarestrup FM, Agerso Y, Gerner-Smidt P, Madsen M, Jensen LB. Comparison of antimicrobial resistance phenotypes and resistance genes in Enterococcus faecalis and Enterococcus faecium from humans in the community, broilers, and pigs in Denmark. Diagn Microbiol Infect Dis. 2000;37:127–37. View ArticlePubMedGoogle Scholar 32.Trzcinski K, Cooper BS, Hryniewicz W, Dowson CG. Expression of resistance to tetracyclines in strains of methicillin-resistant Staphylococcus aureus. J Antimicrob Chemother. 2000;45:763–70. View ArticlePubMedGoogle Scholar 33.Choi JM, Woo GJ. Transfer of tetracycline resistance genes with aggregation substance in food-borne Enterococcus faecalis. Curr Microbiol. 2015;70:476–84. doi:10.1007/s00284-014-0742-1. View ArticlePubMedGoogle Scholar 34.Aminov RI, Garrigues-Jeanjean N, Mackie RI. Molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins. Appl Environ Microbiol. 2001;67:22–32. View ArticlePubMedPubMed CentralGoogle Scholar 35.Leclercq R, Dutka-Malen S, Brisson-Noël A, Molinas C, Derlot E, Arthur M, Duval J, Courvalin P. Resistance of enterococci to aminoglycosides and glycopeptides. Clin Infect Dis. 1992;15:495–501. doi:10.1093/clind/15.3.495. View ArticlePubMedGoogle Scholar

PY - 2017/1/18

Y1 - 2017/1/18

N2 - Background: Enterococci are now well recognised for their ability to transfer antibiotic resistance and for their association with nosocomial infections, but less is known regarding their relevance in the wider environment. Enterococcus faecalis and Enterococcus faecium were isolated from a range of agrarian associated sources (low-flow water, septic tank, poultry litter, high flow water, slurry/soil) and were assessed for latent ability to transfer antimicrobial resistance. Results: The isolates were tested for phenotypic clumping in the presence of cell-free supernatant from other isolates. Some isolates were identified which demonstrated clumping, indicating that they possessed peptide sex pheromone conjugal machinery. All isolates were also tested for antibiotic resistance phenotypes using both disc diffusion and minimum inhibitory concentration (MIC) assays. These tests revealed that the enterococci demonstrated both phenotypic clumping and antibiotic resistance phenotypes. Based on these selection criteria, the isolates were identified as having the potential for horizontal gene transfer and were used to investigate the transfer of multiple antibiotic resistance phenotypes. Conjugal transfer of antibiotic resistance phenotypes was determined using a solid agar mating method followed by a standard antibiotic selection test resulting in different transfer patterns. An interspecies conjugal transfer of vancomycin resistance from E. faecalis to E. faecium was identified while the remaining reactions were within the same species. Transfer efficiencies ranging from 2x10-1 to 2.3x10-5 were determined based on the reactions of three donor isolates (MF06036, MF0410 and MF06035) and two recipient isolates (MW01105Rif and ST01109Rif), with the transfer of vancomycin, erythromycin and tetracycline resistance genes. Conclusions: The conjugation reactions and selection conditions used in this study resulted in a variety of co-transferred resistance phenotypes suggesting the presence of different mobile elements in the set of natural isolates. This study highlights the potential for extensive horizontal gene transfer in a previously neglected reservoir for enterococci.

AB - Background: Enterococci are now well recognised for their ability to transfer antibiotic resistance and for their association with nosocomial infections, but less is known regarding their relevance in the wider environment. Enterococcus faecalis and Enterococcus faecium were isolated from a range of agrarian associated sources (low-flow water, septic tank, poultry litter, high flow water, slurry/soil) and were assessed for latent ability to transfer antimicrobial resistance. Results: The isolates were tested for phenotypic clumping in the presence of cell-free supernatant from other isolates. Some isolates were identified which demonstrated clumping, indicating that they possessed peptide sex pheromone conjugal machinery. All isolates were also tested for antibiotic resistance phenotypes using both disc diffusion and minimum inhibitory concentration (MIC) assays. These tests revealed that the enterococci demonstrated both phenotypic clumping and antibiotic resistance phenotypes. Based on these selection criteria, the isolates were identified as having the potential for horizontal gene transfer and were used to investigate the transfer of multiple antibiotic resistance phenotypes. Conjugal transfer of antibiotic resistance phenotypes was determined using a solid agar mating method followed by a standard antibiotic selection test resulting in different transfer patterns. An interspecies conjugal transfer of vancomycin resistance from E. faecalis to E. faecium was identified while the remaining reactions were within the same species. Transfer efficiencies ranging from 2x10-1 to 2.3x10-5 were determined based on the reactions of three donor isolates (MF06036, MF0410 and MF06035) and two recipient isolates (MW01105Rif and ST01109Rif), with the transfer of vancomycin, erythromycin and tetracycline resistance genes. Conclusions: The conjugation reactions and selection conditions used in this study resulted in a variety of co-transferred resistance phenotypes suggesting the presence of different mobile elements in the set of natural isolates. This study highlights the potential for extensive horizontal gene transfer in a previously neglected reservoir for enterococci.

KW - Enterococci – Water – Conjugation – Vancomycin resistance – Erythromycin resistance – Tetracycline resistance

U2 - 10.1186/s12866-017-0928-3

DO - 10.1186/s12866-017-0928-3

M3 - Article

VL - 17

JO - BMC Microbiology

T2 - BMC Microbiology

JF - BMC Microbiology

SN - 1471-2180

IS - 19

ER -