Riess Tanja, Raddatz Günter, Linke Dirk, Schäfer Andrea, Kempf Volkhard A J
Institut für Medizinische Mikrobiologie und Hygiene, Elfriede-Aulhorn-Str. 6, D-72076 Tübingen, Germany.
Infect Immun. 2007 Jan;75(1):35-43. doi: 10.1128/IAI.00963-06. Epub 2006 Oct 23.
Bartonella henselae causes cat scratch disease and the vasculoproliferative disorders bacillary angiomatosis and peliosis hepatis in humans. One of the best known pathogenicity factors of B. henselae is Bartonella adhesin A (BadA), which is modularly constructed, consisting of head, neck/stalk, and membrane anchor domains. BadA is important for the adhesion of B. henselae to extracellular-matrix proteins and endothelial cells (ECs). In this study, we analyzed different B. henselae strains for BadA expression, autoagglutination, fibronectin (Fn) binding, and adhesion to ECs. We found that the B. henselae strains Marseille, ATCC 49882, Freiburg 96BK3 (FR96BK3), FR96BK38, and G-5436 express BadA. Remarkably, BadA expression was lacking in a B. henselae ATCC 49882 variant, in strains ATCC 49793 and Berlin-1, and in the majority of bacteria of strain Berlin-2. Adherence of B. henselae to ECs and Fn reliably correlated with BadA expression. badA was present in all tested strains, although the length of the gene varied significantly due to length variations of the stalk region. Sequencing of the promoter, head, and membrane anchor regions revealed only minor differences that did not correlate with BadA expression, apart from strain Berlin-1, in which a 1-bp deletion led to a frameshift in the head region of BadA. Our data suggest that, apart from the identified genetic modifications (frameshift deletion and recombination), other so-far-unknown regulatory mechanisms influence BadA expression. Because of variations between and within different B. henselae isolates, BadA expression should be analyzed before performing infection experiments with B. henselae.
汉赛巴尔通体可引起人类猫抓病以及血管增生性疾病杆菌性血管瘤和肝紫癜。汉赛巴尔通体最著名的致病因素之一是巴尔通体黏附素A（BadA），它由头部、颈部/柄部和膜锚定结构域模块化构建而成。BadA对于汉赛巴尔通体黏附细胞外基质蛋白和内皮细胞（ECs）很重要。在本研究中，我们分析了不同汉赛巴尔通体菌株的BadA表达、自凝、纤连蛋白（Fn）结合以及对ECs的黏附情况。我们发现汉赛巴尔通体菌株马赛、ATCC 49882、弗莱堡96BK3（FR96BK3）、FR96BK38和G - 5436表达BadA。值得注意的是，汉赛巴尔通体ATCC 49882的一个变体、菌株ATCC 49793和柏林 - 1以及柏林 - 2的大多数细菌均缺乏BadA表达。汉赛巴尔通体对ECs和Fn的黏附与BadA表达可靠相关。所有测试菌株中均存在badA基因，尽管由于柄部区域长度的变化，该基因的长度差异显著。对启动子、头部和膜锚定区域的测序仅发现了微小差异，这些差异与BadA表达无关，但柏林 - 1菌株除外，该菌株中一个1碱基缺失导致BadA头部区域出现移码。我们的数据表明，除了已确定的基因修饰（移码缺失和重组）外，其他迄今未知的调控机制也会影响BadA表达。由于不同汉赛巴尔通体分离株之间以及分离株内部存在差异，在进行汉赛巴尔通体感染实验之前，应分析BadA表达情况。
