Huycke M M, Gilmore M S
Department of Veterans Affairs Medical Center, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
Plasmid. 1995 Sep;34(2):152-6. doi: 10.1006/plas.1995.9992.
Enterococcus faecalis blood isolates were probed for the serine protease activator of cytolysin (cylA) and aggregation substance (asa1), traits that generally reside on pheromone-responsive plasmids, to determine how commonly these genotypes were associated with disease. In dot blot assays, no significant difference was found in the frequency of asa1 for blood isolates [55 of 103 (54%)] and isolates recovered from stool [9 of 14 (60%); P > 0.1, chi 2 test]. In contrast, cylA occurred more frequently among bacteremia isolates [34 of 68 (50%)] than endocarditis [4 of 35 (11%)] or stool isolates (0 of 14; P < 0.001; chi 2 test). However, when the clonality of isolates was accounted for, the frequency of asa1 and cylA among unrelated strains was not significantly different among the three sets of strains (P > 0.2, chi 2 test). The lack of enrichment for asa1 or cylA among clonally unrelated E. faecalis bloodstream isolates fails to support a role for plasmid-encoded aggregation substance or cytolysin in the transition from bacteremia to endocarditis. Clonally related, cytolytic strains, however, demonstrated an increased propensity to cause bloodstream infection.
对粪肠球菌血液分离株进行细胞溶素丝氨酸蛋白酶激活剂（cylA）和聚集物质（asa1）检测，这些特性通常存在于信息素反应性质粒上，以确定这些基因型与疾病的关联频率。在斑点印迹分析中，血液分离株[103株中有55株（54%）]和粪便中分离株[14株中有9株（60%）；P>0.1，卡方检验]的asa1频率无显著差异。相比之下，cylA在菌血症分离株[68株中有34株（50%）]中出现的频率高于心内膜炎分离株[35株中有4株（11%）]或粪便分离株（14株中0株；P<0.001；卡方检验）。然而，当考虑分离株的克隆性时，三组菌株中不相关菌株的asa1和cylA频率无显著差异（P>0.2，卡方检验）。在克隆不相关的粪肠球菌血流分离株中，asa1或cylA缺乏富集，这并不支持质粒编码的聚集物质或细胞溶素在从菌血症转变为心内膜炎过程中的作用。然而，克隆相关的溶细胞菌株表现出引起血流感染的倾向增加。
