title: Mosaic tetracycline resistance genes and their flanking regions in Bifidobacterium thermophilum and Lactobacillus johnsonii.
abstract: For the first time, mosaic tetracycline resistance genes were identified in Lactobacillus johnsonii and in Bifidobacterium thermophilum strains. The L. johnsonii strain investigated contains a complex hybrid gene, tet(O/W/32/O/W/O), whereas the five bifidobacterial strains possess two different mosaic tet genes: i.e., tet(W/32/O) and tet(O/W). As reported by others, the crossover points of the mosaic tet gene segments were found at similar positions within the genes, suggesting a hot spot for recombination. Analysis of the sequences flanking these genes revealed that the upstream part corresponds to the 5' end of the mosaic open reading frame. In contrast, the downstream region was shown to be more variable. Surprisingly, in one of the B. thermophilum strains a third tet determinant was identified, coding for the efflux pump Tet(L).
authors.affiliation: RIKILT-Institute of Food Safety, Wageningen UR, Bornsesteeg 45, NL-6708PD Wageningen, The Netherlands. angela.vanhoek@wur.nl
authors.forename: Angela H A M
authors.initials: AH
authors.lastname: van Hoek
authors.forename: Sigrid
authors.initials: S
authors.lastname: Mayrhofer
authors.forename: Konrad J
authors.initials: KJ
authors.lastname: Domig
authors.forename: Ana B
authors.initials: AB
authors.lastname: Flórez
authors.forename: Mohammed S
authors.initials: MS
authors.lastname: Ammor
authors.forename: Baltasar
authors.initials: B
authors.lastname: Mayo
authors.forename: Henk J M
authors.initials: HJ
authors.lastname: Aarts
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D001644:Bifidobacterium / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D002352:Carrier Proteins / Q000235:genetics; D004269:DNA, Bacterial / Q000032:analysis; D005243:Feces / Q000382:microbiology; D006801:Humans; D007778:Lactobacillus / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D013552:Swine; D013753:Tetracycline Resistance / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; C083139:Tet O resistance protein, Bacteria