title: Antibacterials that are used as growth promoters in animal husbandry can affect the release of Shiga-toxin-2-converting bacteriophages and Shiga toxin 2 from Escherichia coli strains.
abstract: Antibiotics are commonly used as growth promoters in animal husbandry worldwide. This practice has been linked to the emergence of particular antibiotic-resistant bacteria, and is now controversial. In this study, the ability of growth-promoting antibiotics to induce Shiga toxin (Stx)-converting bacteriophages from Stx-producing Escherichia coli (STEC) strains was investigated. Subinhibitory concentrations of the antibacterial growth promoters olaquindox, carbadox, tylosin and monensin were used for induction experiments. The amount of mature Stx-converting phage particles released from induced and non-induced cultures was determined, and the production of Stx was simultaneously measured by ELISA. Whereas the quinoxaline-1,4-dioxide-type antibiotics olaquindox and carbadox enhanced the release of Stx-converting phage particles from STEC cells, tylosin and monensin decreased phage induction. The production of Stx increased or decreased simultaneously with the amount of free phages. The results of this study show that particular antibacterial growth promoters can induce Stx phages. In vivo induction of Stx phages from lysogenic STEC may increase the amount of free phages in the intestine and therefore may contribute to the spread of STEC and development of new STEC pathotypes.
authors.affiliation: Institut für Hygiene und Mikrobiologie der Universität Würzburg, Josef-Schneider-Str. 2, D-97080 Würzburg, Germany1.
authors.forename: Bernd
authors.initials: B
authors.lastname: Köhler
authors.affiliation: Institut für Hygiene und Mikrobiologie der Universität Würzburg, Josef-Schneider-Str. 2, D-97080 Würzburg, Germany1.
authors.forename: Helge
authors.initials: H
authors.lastname: Karch
authors.affiliation: Institut für Hygiene und Mikrobiologie der Universität Würzburg, Josef-Schneider-Str. 2, D-97080 Würzburg, Germany1.
authors.forename: Herbert
authors.initials: H
authors.lastname: Schmidt
mesh_terms: D000822:Animal Husbandry; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000032:analysis / Q000378:metabolism*; D001435:Bacteriophages / Q000187:drug effects* / Q000378:metabolism; D002218:Carbadox / Q000494:pharmacology; D019453:Escherichia coli O157 / Q000187:drug effects* / Q000378:metabolism / Q000821:virology; D006133:Growth Substances / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D008985:Monensin / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D022603:Shiga Toxins; D015645:Tylosin / Q000494:pharmacology; D010948:Viral Plaque Assay
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D001427:Bacterial Toxins; D006133:Growth Substances; D011810:Quinoxalines; D022603:Shiga Toxins; D008985:Monensin; C013168:olaquindox; D002218:Carbadox; D015645:Tylosin