title: Plasmid-mediated resistance to antimicrobial agents among listeriae.
abstract: The resistance to 14 antiseptic-disinfectant and dye compounds of 208 strains of Listeria (132 L. monocytogenes, 63 L. innocua, 8 L. seeligeri, 1 L. ivanovii, 1 L. welshimeri, and 3 Listeria spp.) was tested by the agar-dilution procedure. The Listeria strains were isolated from different varieties of foods, environments of cheese dairies, humans, and wild birds. A total of 14 (6.7%) Listeria strains (12 L. monocytogenes and 2 L. innocua) were resistant to benzalkonium chloride, hexamidine diisethionate, and ethidium bromide. This multiple resistance was observed more frequently from strains of Listeria spp. detected on carcasses of poultry (47%) than strains isolated from human listeriosis cases or carriers (11.5%), red meats (10%), cheeses (5.4%), wild birds (0.9%), and environments of cheese dairies (0%). Among resistant strains, 10 groups of strains (71.5%) were differentiated by serogroup, phage typing, and sensitivity or resistance to cadmium. Extrachromosomal DNA was found in all resistant strains and was transferred at a high frequency among Listeria spp. (8.7 x 10(-6) to 1 x 10(-3) transconjugant CFUs per one donor CFU). These resistances were also transferable between L. monocytogenes and Staphylococcus aureus with similar transfer frequencies (7.8 x 10(-6) to 1 x 10(-4) and between strains of Staphylococcus aureus with similar transfer frequencies from 8 x 10(-7) to 3.3 x 10(-6). These results suggest that emergence of this multiple resistance in Listeria spp. could be due to acquisition of a replicon originating in staphylocci.
authors.affiliation: Laboratoire de Microbiologie, Faculté de Pharmacie, Université de Bourgogne, Dijon.
authors.forename: J P
authors.initials: JP
authors.lastname: Lemaître
authors.forename: H
authors.initials: H
authors.lastname: Echchannaoui
authors.forename: G
authors.initials: G
authors.lastname: Michaut
authors.forename: C
authors.initials: C
authors.lastname: Divies
authors.forename: A
authors.initials: A
authors.lastname: Rousset
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001434:Bacteriophage Typing; D001717:Birds / Q000382:microbiology; D002104:Cadmium / Q000494:pharmacology; D004396:Coloring Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial / Q000235:genetics*; D018432:Drug Resistance, Multiple / Q000235:genetics; D005516:Food Microbiology; D006801:Humans; D008087:Listeria / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D008088:Listeriosis / Q000382:microbiology; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics*; D012703:Serotyping
chemical_list: D000900:Anti-Bacterial Agents; D004396:Coloring Agents; D002104:Cadmium