title: Tetracycline resistance in Chlamydia suis mediated by genomic islands inserted into the chlamydial inv-like gene.
abstract: Many strains of Chlamydia suis, a pathogen of pigs, express a stable tetracycline resistance phenotype. We demonstrate that this resistance pattern is associated with a resistance gene, tet(C), in the chlamydial chromosome. Four related genomic islands were identified in seven tetracycline-resistant C. suis strains. All resistant isolates carry the structural gene tet(C) and the tetracycline repressor gene tetR(C). The islands share significant nucleotide sequence identity with resistance plasmids carried by a variety of different bacterial species. Three of the four tet(C) islands also carry a novel insertion sequence that is homologous to the IS605 family of insertion sequences. In each strain, the resistance gene and associated sequences are recombined into an identical position in a gene homologous to the inv gene of the yersiniae. These genomic islands represent the first examples of horizontally acquired DNA integrated into a natural isolate of chlamydiae or within any other obligate intracellular bacterium.
authors.affiliation: Department of Biomedical Sciences, Oregon State University, 106 Dryden Hall, Corvallis, OR 97331-4804, USA. rockeyd@orst.edu
authors.forename: Jae
authors.initials: J
authors.lastname: Dugan
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Rockey
authors.forename: Loren
authors.initials: L
authors.lastname: Jones
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Andersen
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics*; D015139:Blotting, Southern; D002689:Chlamydia / Q000187:drug effects* / Q000235:genetics*; D002522:Chlorocebus aethiops; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D005798:Genes, Bacterial / Q000235:genetics*; D016680:Genome, Bacterial; D006090:Gram-Negative Bacteria / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010957:Plasmids / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D013753:Tetracycline Resistance; D014709:Vero Cells
chemical_list: D001426:Bacterial Proteins; D004251:DNA Transposable Elements; D012097:Repressor Proteins; C107173:TetC protein, Bacteria