Farrow Kylie A, Lyras Dena, Rood Julian I
Bacterial Pathogenesis Research Group, Department of Microbiology, PO Box 53, Monash University, Victoria 3800, Australia1.
Microbiology (Reading). 2001 Oct;147(Pt 10):2717-2728. doi: 10.1099/00221287-147-10-2717.
Clostridium difficile is a nosocomial pathogen that causes a range of chronic intestinal diseases, usually as a result of antimicrobial therapy. Macrolide-lincosamide-streptogramin B (MLS) resistance in C. difficile is encoded by the Erm B resistance determinant, which is thought to be located on a conjugative transposon, Tn5398. The 9630 bp Tn5398 element has been cloned and completely sequenced and its insertion site determined. Analysis of the resultant data reveals that Tn5398 is not a classical conjugative transposon but appears to be a mobilizable non-conjugative element. It does not carry any transposase or site-specific recombinase genes, nor any genes likely to be involved in conjugation. Furthermore, using PCR analysis it has been shown that isolates of C. difficile obtained from different geographical locations exhibit heterogeneity in the genetic arrangement of both Tn5398 and their Erm B determinants. These results indicate that genetic exchange and recombination between these determinants occurs in the clinical and natural environment.
艰难梭菌是一种医院病原体，通常由于抗菌治疗而导致一系列慢性肠道疾病。艰难梭菌对大环内酯-林可酰胺-链阳菌素B（MLS）的耐药性由Erm B耐药决定簇编码，该决定簇被认为位于接合转座子Tn5398上。9630 bp的Tn5398元件已被克隆并完全测序，其插入位点也已确定。对所得数据的分析表明，Tn5398不是经典的接合转座子，而是一种可移动的非接合元件。它不携带任何转座酶或位点特异性重组酶基因，也不携带任何可能参与接合的基因。此外，通过PCR分析表明，从不同地理位置分离得到的艰难梭菌菌株在Tn5398及其Erm B决定簇的基因排列上表现出异质性。这些结果表明，这些决定簇之间的基因交换和重组发生在临床和自然环境中。
