OBJECTIVES: The aim of this study was to investigate the transfer of bacterial doxycycline resistance between oral bacteria in subjects receiving systemic doxycycline for the treatment of periodontitis. PATIENTS AND METHODS: Streptococci were cultured before and after treatment from the subgingival plaque of two patients with periodontitis, genotyped and investigated for the presence of antimicrobial resistance determinants and conjugative transposons. RESULTS: In one subject, a strain of Streptococcus sanguinis resistant to doxycycline was a minor component of the pre-treatment streptococcal flora but dominated post-treatment. In a second subject, a strain of Streptococcus cristatus, which was sensitive to doxycycline before treatment, was found to have acquired a novel conjugative transposon during treatment, rendering it resistant to doxycycline and erythromycin. The novel transposon, named CTn6002, was sequenced and found to be a complex element derived in part from Tn916, and an unknown element which included the erythromycin resistance gene erm(B). A strain of Streptococcus oralis isolated from this subject pre-treatment was found to harbour CTn6002 and was therefore implicated as the donor. CONCLUSIONS: This is the first direct demonstration of transfer of antimicrobial resistance carried on a conjugative transposon between oral bacteria during systemic antimicrobial treatment of periodontitis in humans.
OBJECTIVES: The aim of this study was to investigate the transfer of bacterial doxycycline resistance between oral bacteria in subjects receiving systemic doxycycline for the treatment of periodontitis. PATIENTS AND METHODS: Streptococci were cultured before and after treatment from the subgingival plaque of two patients with periodontitis, genotyped and investigated for the presence of antimicrobial resistance determinants and conjugative transposons. RESULTS: In one subject, a strain of Streptococcus sanguinis resistant to doxycycline was a minor component of the pre-treatment streptococcal flora but dominated post-treatment. In a second subject, a strain of Streptococcus cristatus, which was sensitive to doxycycline before treatment, was found to have acquired a novel conjugative transposon during treatment, rendering it resistant to doxycycline and erythromycin. The novel transposon, named CTn6002, was sequenced and found to be a complex element derived in part from Tn916, and an unknown element which included the erythromycin resistance gene erm(B). A strain of Streptococcus oralis isolated from this subject pre-treatment was found to harbour CTn6002 and was therefore implicated as the donor. CONCLUSIONS: This is the first direct demonstration of transfer of antimicrobial resistance carried on a conjugative transposon between oral bacteria during systemic antimicrobial treatment of periodontitis in humans.
Authors: Paul E Kolenbrander; Robert J Palmer; Saravanan Periasamy; Nicholas S Jakubovics Journal: Nat Rev Microbiol Date: 2010-07 Impact factor: 60.633
Authors: Lisbeth E de Vries; Yvonne Vallès; Yvonne Agersø; Parag A Vaishampayan; Andrea García-Montaner; Jennifer V Kuehl; Henrik Christensen; Miriam Barlow; M Pilar Francino Journal: PLoS One Date: 2011-06-28 Impact factor: 3.240