Antimicrobial susceptibility and antibiotic resistance gene transfer analysis of foodborne, clinical, and environmental Listeria spp. isolates including Listeria monocytogenes. Issue 1 (2nd January 2014)

• Record Type: Journal Article
• Authors: Bertsch, David; Muelli, Mirjam; Weller, Monika; Uruty, Anaïs; Lacroix, Christophe; Meile, Leo
• Is Part Of: MicrobiologyOpen. Volume 3:Issue 1(2014:Feb.)
• Page Start: 118
• Page End: 127
• Publication Date: 2014-01-02
• Subjects: Microbiology -- Periodicals; 579
• DOI: 10.1002/mbo3.155
• Languages: English
• ISSNs: 2045-8827

Abstract

<abstract abstract-type="main" id="mbo3155-abs-0001"> <title>Abstract</title> <p>The aims of this study were to assess antibiotic resistance pheno‐ and genotypes in foodborne, clinical, and environmental <italic>Listeria</italic> isolates, as well as to elucidate the horizontal gene transfer potential of detected resistance genes. A small fraction of in total 524 <italic>Listeria</italic> spp. isolates (3.1%) displayed acquired antibiotic resistance mainly to tetracycline (<italic>n </italic>=<italic> </italic>11), but also to clindamycin (<italic>n </italic>=<italic> </italic>4) and trimethoprim (<italic>n</italic> = 3), which was genotypically confirmed. In two cases, a tetracycline resistance phenotype was observed together with a trimethoprim resistance phenotype, namely in a clinical <italic>L. monocytogenes</italic> strain and in a foodborne <italic>L. innocua</italic> isolate. Depending on the applied guidelines, a differing number of isolates (<italic>n </italic>=<italic> </italic>2 or <italic>n </italic>=<italic> </italic>20) showed values for ampicillin that are on the edge between intermediate susceptibility and resistance. Transferability of the antibiotic resistance genes from the <italic>Listeria</italic> donors, elucidated in vitro by filter matings, was demonstrated for genes located on transposons of the Tn<italic>916</italic> family and for an unknown clindamycin resistance determinant. Transfer rates of up to 10<sup>−5</sup> transconjugants per donor were obtained with a <italic>L. monocytogenes</italic> recipient and up to 10<sup>−7</sup> with an <italic>Enterococcus faecalis</italic> recipient, respectively. Although the prevalence of acquired antibiotic resistance in <italic>Listeria</italic> isolates from this study was rather low, the transferability of these resistances enables further spread in the future. This endorses the importance of surveillance of <italic>L. monocytogenes</italic> and other <italic>Listeria</italic> spp. in terms of antibiotic susceptibility.</p> </abstract>