title: Low Temperature and Modified Atmosphere: Hurdles for Antibiotic Resistance Transfer?
abstract: Food is an important dissemination route for antibiotic-resistant bacteria. Factors used during food production and preservation may contribute to the transfer of antibiotic resistance genes, but research on this subject is scarce. In this study, the effect of temperature (7 to 37°C) and modified atmosphere packaging (air, 50% CO2-50% N2, and 100% N2) on antibiotic resistance transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes was evaluated. Filter mating was performed on nonselective agar plates with high-density inocula. A more realistic setup was created by performing modified atmosphere experiments on cooked ham using high-density and low-density inocula. Plasmid transfer was observed between 10 and 37°C, with plasmid transfer also observed at 7°C during a prolonged incubation period. When high-density inocula were used, transconjugants were detected, both on agar plates and cooked ham, under the three atmospheres (air, 50% CO2-50% N2, and 100% N2) at 7°C. This yielded a median transfer ratio (number of transconjugants/number of recipients) with an order of magnitude of 10(-4) to 10(-6). With low-density inocula, transfer was only detected under the 100% N2 atmosphere after 10-day incubation at 7°C, yielding a transfer ratio of 10(-5). Under this condition, the highest bacterial density was obtained. The results indicate that low temperature and modified atmosphere packaging, two important hurdles in the food industry, do not necessarily prevent plasmid transfer from Lactobacillus sakei subsp. sakei to Listeria monocytogenes.
authors.affiliation: Institute for Agricultural and Fisheries Research, Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium; Laboratory of Food Microbiology and Food Preservation, Laboratory of Microbial Ecology and Technology, Ghent University, Coupure Links 653, 9000 Ghent, Belgium. eva.vanmeervenne@ilvo.vlaanderen.be.
authors.forename: Eva
authors.initials: E
authors.lastname: Van Meervenne
authors.affiliation: Institute for Agricultural and Fisheries Research, Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
authors.forename: Els
authors.initials: E
authors.lastname: Van Coillie
authors.affiliation: Institute for Agricultural and Fisheries Research, Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Van Weyenberg
authors.forename: Nico
authors.initials: N
authors.lastname: Boon
authors.affiliation: Institute for Agricultural and Fisheries Research, Technology and Food Science Unit, Brusselsesteenweg 370, 9090 Melle, Belgium.
authors.forename: Lieve
authors.initials: L
authors.lastname: Herman
authors.affiliation: Laboratory of Food Microbiology and Food Preservation.
authors.forename: Frank
authors.initials: F
authors.lastname: Devlieghere
mesh_terms: D000362:Agar / Q000737:chemistry; D000388:Air; D000818:Animals; D002245:Carbon Dioxide; D003080:Cold Temperature; D003296:Cooking; D004352:Drug Resistance, Microbial; D005511:Food Handling; D019649:Food Industry; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus; D008089:Listeria monocytogenes; D008460:Meat; D009584:Nitrogen / Q000737:chemistry; D010957:Plasmids / Q000378:metabolism; D013552:Swine
chemical_list: D002245:Carbon Dioxide; D000362:Agar; D009584:Nitrogen