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Genetic transfer systems in Bacteroides : cloning and mapping of the transferable tetracycline‐resistance locus
Author(s) -
Guiney D. G.,
Hasegawa P.,
Bouic K.,
Matthews B.
Publication year - 1989
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1989.tb00147.x
Subject(s) - biology , shuttle vector , locus (genetics) , plasmid , bacteroides fragilis , bacteroides , genetics , tetracycline , gene , molecular cloning , escherichia coli , dna , microbiology and biotechnology , recombinant dna , vector (molecular biology) , bacteria , antibiotics , gene expression
Summary Conjugation systems that transfer antibiotic resistance in the absence of detectable plasmids are common in Bacteroides , but the mechanism of transfer is poorly understood. We found that linked transfer of tetracycline (To R ) and clindamycin (CI R ) resistance by Bacteroides fragilis strain 1126 is induced by growth in either Tc or Cl. We cloned the transferable Tc R locus as a 13 kb fragment on the shuttle vector pPH6 in Escherichia coli and showed that this region expresses Tc R in Bacteroides but not E. coli. The Tc R gene was mapped to a 3 kb region and the CI R gene was shown not to be present in the 13 kb insert. Homologous Tc R genes are found in B. fragilis V479 and 1792. Using pulsed‐field electrophoresis, the transferable Tc R gene was shown to be physically associated with high molecular‐weight DNA, suggesting that it is located on the chromosome. A new Tc R shuttle vector. pPH7δ1.1, was constructed to facilitate use of this selective marker in Bacteroides genetics.