Studies on <beta> -hemolysin toxin of Streptococcus faecalis

粪链球菌产生的溶血素已被证明有助于小鼠的毒力。对日本97株粪球菌临床分离株的溶血素分泌、凝块（费洛蒙）反应、溶血特性的可转移性、溶血质粒结构及耐药性进行了检测。分离株来自各种来源（即尿液、脓液、阴道、痰液、胆汁和血液），其中约60%为溶血性。与约49%的非溶血菌株相比，约85%的溶血菌株表现出结块反应。超过50%的溶血菌株携带可转移溶血素决定因子，并且在任何情况下都没有耐药性基因相关。溶血性菌株比非溶血性菌株更容易出现多重耐药。与肠外分离株产生溶血素的频率较高相比，来自健康个体粪便标本的菌株产生溶血素的发生率较低（17%）。溶血素-细菌素质粒pAD1（56.7kb）分离于密歇根州安娜堡，是粪球菌中分析较好的结合质粒之一。在本研究中发现11个可转移的cad1响应质粒在结构上类似于pAD1（限制性内切片段）。

Hemolysin produced by Streptococcus faecalis has been shown to contribute to virulence in mice. Hemolysin production, clumping (pheromone) response, transferability of the hemolytic trait, structure of the hemolytic plasmid, and drug resistance were examined in 97 clinical isolates of S.faecalis in Japan.The isolates were derived from various sources (i.e., urine, pus, vaginal, sputum, bile and blood), and approximately 60% were found to be hemolytic. About 85% of the hemolytic strains exhibited a clumping response compared to about 49% of the non-hemolytic strains. Over 50% of the hemolytic strains carried transferable hemolysin determinants, and in no case were drug-resistance genes linked. The hemolytic strains exhibited multiple drug-resistance more frequently than the non-hemolytic strains. In contrast to the high frequency of hemolysin producers among parenteral isolates, strains derived from fecal specimens of healthy individuals exhibited a low (17%) incidence of hemolysin production.Hemolysin-bacteriocin plasmid pAD1(56.7kb), isolated in Ann Arbor, MI, is one of the well analyzed conjugative plasmids in S.faecalis. Eleven transferable cAD1-responding plasmids in the present study were found to structurally resemble (restriction fragments) pAD1.