Aarestrup F M, Larsen H D, Eriksen N H, Elsberg C S, Jensen N E
Danish Veterinary Laboratory, Copenhagen.
APMIS. 1999 Apr;107(4):425-30.
The phenotypic expression of haemolysins and the presence of genes encoding alpha and beta-haemolysin were determined in 105 Staphylococcus aureus isolates from bovine mastitis, 100 isolates from the nostrils of healthy humans, and 60 isolates from septicaemia in humans. Furthermore, the possible change in expression of haemolysins after subcultivation in human and bovine blood and milk was studied in selected isolates. Alpha-haemolysin was expressed phenotypically in 39 (37%) of the bovine isolates, in 59 (59%) of the human carrier isolates, and in 40 (67%) of the isolates from septicaemia. Beta-haemolysin was expressed in 76 (72%) bovine, 11 (11%) carrier, and 8 (13%) septicaemia isolates. Significantly more bovine than human isolates expressed beta-haemolysin and significantly fewer expressed alpha-haemolysin. Genotypically, the gene encoding alpha-haemolysin was detected in all isolates. A significant difference in the prevalence of the gene encoding beta-haemolysin between the bovine (96%), human carrier (56%) and isolates from septicaemia (57%) was found. Of the bovine isolates, 75% of those carrying the gene encoding beta-haemolysin expressed beta-haemolysin phenotypically, whereas only 20% of the carrier isolates and 24% of the septicaemia isolates did so. No change in expression of haemolysins could be observed after subcultivation of bovine isolates in human blood and milk. After 5 to 10 subcultures in bovine blood and 1 to 4 in bovine milk, 9 of 10 human isolates originally phenotypically beta-haemolysin negative initiated the expression of beta-haemolysin. This study showed that a larger proportion of S. aureus of bovine origin carry the beta-haemolysin gene compared to isolates from humans. Furthermore, a larger number of the isolates of bovine origin carrying the beta-haemolysin gene express this gene phenotypically compared to isolates of human origin.
在105株来自牛乳腺炎的金黄色葡萄球菌分离株、100株来自健康人鼻孔的分离株以及60株来自人类败血症的分离株中，测定了溶血素的表型表达以及编码α和β溶血素的基因的存在情况。此外，还对选定的分离株在人血和牛血及牛奶中传代培养后溶血素表达的可能变化进行了研究。α溶血素在39株（37%）牛源分离株、59株（59%）人类携带者分离株以及40株（67%）败血症分离株中表现出表型表达。β溶血素在76株（72%）牛源、11株（11%）携带者和8株（13%）败血症分离株中表达。表达β溶血素的牛源分离株显著多于人类分离株，而表达α溶血素的则显著少于人类分离株。从基因层面看，在所有分离株中均检测到了编码α溶血素的基因。在牛源（96%）、人类携带者（56%）和败血症分离株（57%）中，编码β溶血素的基因的流行率存在显著差异。在携带编码β溶血素基因的牛源分离株中，75%在表型上表达β溶血素，而在携带者分离株和败血症分离株中，只有20%和24%表达该溶血素。牛源分离株在人血和牛奶中传代培养后，未观察到溶血素表达的变化。在牛血中传代5至10次以及在牛奶中传代1至4次后，10株原本表型为β溶血素阴性的人类分离株中有9株开始表达β溶血素。这项研究表明，与人类分离株相比，更大比例的牛源金黄色葡萄球菌携带β溶血素基因。此外，与人类来源的分离株相比，更多携带β溶血素基因的牛源分离株在表型上表达该基因。
