Warburton Philip J, Palmer Richard M, Munson Mark A, Wade William G
King's College London Dental Institute at Guy's, King's College and St Thomas' Hospitals, Infection Research Group, Guy's Campus, London SE1 9RT, UK.
J Antimicrob Chemother. 2007 Nov;60(5):973-80. doi: 10.1093/jac/dkm331. Epub 2007 Sep 13.
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.
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.
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.
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.
本研究旨在调查在接受全身性强力霉素治疗牙周炎的受试者中，口腔细菌之间强力霉素耐药性的转移情况。
从两名牙周炎患者的龈下菌斑中培养治疗前后的链球菌，进行基因分型，并调查抗菌药物耐药性决定因素和接合转座子的存在情况。
在一名受试者中，一株对强力霉素耐药的血链球菌在治疗前是链球菌菌群的次要成分，但在治疗后占主导地位。在另一名受试者中，一株在治疗前对强力霉素敏感的嵴链球菌在治疗期间获得了一种新的接合转座子，使其对强力霉素和红霉素耐药。对这个名为CTn6002的新转座子进行测序，发现它是一个复杂元件，部分源自Tn916，还有一个未知元件，其中包括红霉素耐药基因erm(B)。从该受试者治疗前分离出的一株口腔链球菌被发现携带CTn6002，因此被认为是供体。
这是首次直接证明在人类牙周炎的全身性抗菌治疗期间，接合转座子携带的抗菌药物耐药性在口腔细菌之间发生转移。
