Dinu Sorin, Damian Maria, Badell Edgar, Dragomirescu Cristiana Cerasella, Guiso Nicole
"Cantacuzino" National Institute of Research and Development for Microbiology and Immunology, Molecular Epidemiology Laboratory, Bucharest, Romania.
J Basic Microbiol. 2014 Oct;54(10):1136-9. doi: 10.1002/jobm.201300686. Epub 2013 Dec 2.
Corynebacterium diphtheriae is the etiological agent of diphtheria, a potential fatal disease caused by a corynephage toxin. The expression of this diphtheria toxin is controlled via an iron-dependent repressor with various functions (DtxR). Some mutations in the dtxR gene are associated with diminished activity or even with total loss of DtxR function. We conducted a molecular study to characterize the dtxR alleles harbored by 34 isolates of C. diphtheriae recovered from Romanian patients between 1961 and 2007. Three of the seven alleles identified in this study have not previously been described. Two new DtxR types were identified, one of which has an unusual polypeptide length. All the new DtxR types were found in toxigenic isolates, suggesting that they effectively regulate the expression of diphtheria toxin. Furthermore, one of the new DtxR identified was also found in a non-toxigenic isolate, making it a potential source of toxigenic isolates after lysogenic conversion.
白喉棒状杆菌是白喉的病原体，白喉是一种由棒状噬菌体毒素引起的潜在致命疾病。这种白喉毒素的表达通过具有多种功能的铁依赖性阻遏物（DtxR）进行控制。dtxR基因中的一些突变与活性降低甚至DtxR功能完全丧失有关。我们进行了一项分子研究，以表征1961年至2007年间从罗马尼亚患者中分离出的34株白喉棒状杆菌所携带的dtxR等位基因。本研究中鉴定出的七个等位基因中有三个此前未被描述。鉴定出了两种新的DtxR类型，其中一种具有不寻常的多肽长度。所有新的DtxR类型都在产毒菌株中发现，这表明它们有效地调节了白喉毒素的表达。此外，鉴定出的一种新的DtxR也在无毒菌株中发现，这使其成为溶原性转化后产毒菌株的潜在来源。
