Genetic analysis of bacteriocin 43 of vancomycin-resistant Enterococcus faecium
Genetic analysis of bacteriocin 43 of vancomycin-resistant Enterococcus faecium
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DOI：
10.1128/aem.00934-06
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发表时间：
2006-11-01
影响因子：
4.4
通讯作者：
Ike, Yasuyoshi
中科院分区：
文献类型：
--
作者：
Todokoro, Daisuke;Tomita, Haruyoshi;Ike, Yasuyoshi
对1994年至1999年间从密歇根大学医学院医院获得的636株耐万古霉素屎肠球菌（VRE）进行了细菌素生产检测。277株（44%）产菌菌株中，有21株对粪肠杆菌、粪肠杆菌、赫拉肠杆菌、杜兰肠杆菌和单核增生李斯特菌有活性。在这21株菌株中，发现菌株VRE82具有代表性的细菌素，命名为细菌素43，编码在可移动质粒pDT1 （6.2 kbp）上。pDT1上显示9个开放阅读框（orf）， ORF1 ~ ORF9，排列方向相同。细菌素43位点（bac43）由细菌素基因bacA （ORFI）和免疫基因bacB （ORF2）组成。推导出的bacA产物长度为74个氨基酸，在N端假定有30个氨基酸的信号肽。bacB基因编码一个没有信号序列的95个氨基酸的蛋白质。预测的成熟BacA蛋白（44个氨基酸）序列与乳酸菌具有膜活性的IIa类细菌素序列同源，与粪肠杆菌YI717的细菌素31同源性为86%，与细菌素RC714同源性为98%。用bac43探针对21株菌株的每个质粒DNA进行Southern分析，发现与6.2 kbp EcoRI片段对应的特定片段杂交，表明菌株含有编码43型细菌素的pdt1样质粒（6.2 kb）。在非vre临床分离株中未发现bac43决定因素。
A total of 636 vancomycin-resistant Enterococcus faecium (VRE) isolates obtained between 1994 and 1999 from the Medical School Hospital of the University of Michigan were tested for bacteriocin production. Of the 277 (44%) bacteriocinogenic strains, 21 were active against E. faecalis, E. faecium, E. hirae, E. durans, and Listeria monocytogenes. Of those 21 strains, a representative bacteriocin of strain VRE82, designated bacteriocin 43, was found to be encoded on mobilizable plasmid pDT1 (6.2 kbp). Nine open reading frames (ORFs), ORF1 to ORF9, were presented on pDT1 and were oriented in the same direction. The bacteriocin 43 locus (bac43) consists of the bacteriocin gene bacA (ORFI) and the immunity gene bacB (ORF2). The deduced bacA product is 74 amino acids in length with a putative signal peptide of 30 amino acids at the N terminus. The bacB gene encodes a deduced 95-amino-acid protein without a signal sequence. The predicted mature BacA protein (44 amino acids) showed sequence homology with the membrane-active class IIa bacteriocins of lactic acid bacteria and showed 86% homology with bacteriocin 31 from E. faecalis YI717 and 98% homology with bacteriocin RC714. Southern analysis with a bac43 probe of each plasmid DNA from the 21 strains showed hybridization to a specific fragment corresponding to the 6.2-kbp EcoRI fragment, suggesting that the strains harbored the pDT1-like plasmid (6.2 kb) which encoded the bacteriocin 43-type bacteriocin. The bac43 determinant was not identified among non-VRE clinical isolates.