| Autor: |
Suchland, R. J., Sandoz, K. M., Jeffrey, B. M., Stamm, W. E., Rockey, D. D. |
| Zdroj: |
Antimicrobial Agents and Chemotherapy; November 2009, Vol. 53 Issue: 11 p4604-4611, 8p |
| Abstrakt: |
ABSTRACTThere are no examples of stable tetracycline resistance in clinical strains of Chlamydia trachomatis. However, the swine pathogen Chlamydia suisis commonly tetracycline resistant, both in America and in Europe. In tested U.S. strains, this resistance is mediated by a genomic island carrying a tet(C) allele. In the present study, the ability of C. suisto mobilize tet(C) into other chlamydial species was examined. Differently antibiotic resistant strains of C. suis, C. trachomatis, and Chlamydia muridarumwere used in coculture experiments to select for multiply antibiotic resistant progeny. Coinfection of mammalian cells with a naturally occurring tetracycline-resistant strain of C. suisand a C. muridarumor C. trachomatisstrain containing selected mutations encoding rifampin (rifampicin) or ofloxacin resistance readily produced doubly resistant recombinant clones that demonstrated the acquisition of tetracycline resistance. The resistance phenotype in the progeny from a C. trachomatisL2/oflR-C. suisR19/tetRcross resulted from integration of a 40-kb fragment into a single ribosomal operon of a recipient, leading to a merodiploid structure containing three rRNA operons. In contrast, a cross between C. suisR19/tetRand C. muridarumMoPn/oflRled to a classical double-crossover event transferring 99 kb of DNA from C. suisR19/tetRinto C. muridarumMoPn/oflR. Tetracycline resistance was also transferred to recent clinical strains of C. trachomatis. Successful crosses were not obtained when a rifampin-resistant Chlamydophila caviaestrain was used as a recipient for crosses with C. suisor C. trachomatis. These findings provide a platform for further exploration of the biology of horizontal gene transfer in Chlamydiawhile bringing to light potential public health concerns generated by the possibility of acquisition of tetracycline resistance by human chlamydial pathogens. |
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