Research Department of Microbial Diseases, UCL Eastman Dental Institute, 256 Gray's Inn Road, University College London, London WC1X 8LD, UK.
J Antimicrob Chemother. 2013 Jan;68(1):17-22. doi: 10.1093/jac/dks351. Epub 2012 Aug 30.
To identify the genes responsible for tetracycline resistance in a strain of Streptococcus australis isolated from pooled saliva from healthy volunteers in France. S. australis is a viridans Streptococcus, originally isolated from the oral cavity of children in Australia, and subsequently reported in the lungs of cystic fibrosis patients and as a cause of invasive disease in an elderly patient.
Agar containing 2 mg/L tetracycline was used for the isolation of tetracycline-resistant organisms. A genomic library in Escherichia coli was used to isolate the tetracycline resistance determinant. In-frame deletions and chromosomal repair were used to confirm function. Antibiotic susceptibility was determined by agar dilution and disc diffusion assay.
The tetracycline resistance determinant from S. australis FRStet12 was isolated from a genomic library in E. coli and DNA sequencing showed two open reading frames predicted to encode proteins with similarity to multidrug resistance-type ABC transporters. Both genes were required for tetracycline resistance (to both the naturally occurring and semi-synthetic tetracyclines) and they were designated tetAB(46).
This is the first report of a predicted ABC transporter conferring tetracycline resistance in a member of the oral microbiota.
鉴定从法国健康志愿者混合唾液中分离的一株澳大利亚链球菌中负责四环素耐药的基因。澳大利亚链球菌是一种草绿色链球菌，最初从澳大利亚儿童的口腔中分离出来，随后在囊性纤维化患者的肺部和老年患者的侵袭性疾病中被报道。
使用含 2mg/L 四环素的琼脂分离四环素耐药菌。使用大肠杆菌基因组文库分离四环素耐药决定簇。通过框内缺失和染色体修复来确认功能。通过琼脂稀释法和药敏纸片扩散法测定抗生素敏感性。
从澳大利亚链球菌 FRStet12 的基因组文库中分离出的四环素耐药决定簇在大肠杆菌中进行了 DNA 测序，结果显示两个开放阅读框预测编码与多药耐药型 ABC 转运蛋白具有相似性的蛋白质。这两个基因都需要四环素耐药（对天然和半合成四环素都需要），并将其命名为 tetAB(46)。
这是口腔微生物群中一种预测的 ABC 转运蛋白赋予四环素耐药性的首次报道。
