Murray B E, Mederski-Samoraj B, Foster S K, Brunton J L, Harford P
J Clin Invest. 1986 Jan;77(1):289-93. doi: 10.1172/JCI112289.
A strain of Streptococcus faecalis with plasmid-mediated penicillinase production was studied further. Partially purified penicillinase from the S. faecalis strain hydrolyzed penicillin, ampicillin, and ureido-penicillins but not penicillinase-resistant semisynthetic penicillins, cephalosporins, or imipenem; hydrolysis was inhibited by clavulanic acid. Hydrolysis of a given antibiotic correlated with a marked increase in the minimal inhibitory concentration (MIC) of that drug when a high inoculum was used. As with most enterococci, the MICs of cephalosporins and penicillinase-resistant semisynthetic penicillins were too high for clinical usefulness, although these agents did not show an inoculum effect. Based upon hybridization under stringent conditions of plasmid DNA from the S. faecalis strain to cloned penicillinase genes from Staphylococcus aureus, it appears that these resistance determinants are highly homologous and suggests that this enzyme was introduced into streptococci from staphylococci.
对一株产质粒介导青霉素酶的粪肠球菌进行了进一步研究。从该粪肠球菌菌株中部分纯化得到的青霉素酶可水解青霉素、氨苄西林和脲基青霉素，但不能水解耐青霉素酶的半合成青霉素、头孢菌素或亚胺培南；水解作用受到克拉维酸的抑制。当使用高接种量时，特定抗生素的水解与该药物的最低抑菌浓度（MIC）显著增加相关。与大多数肠球菌一样，头孢菌素和耐青霉素酶的半合成青霉素的MIC过高，不具有临床实用性，尽管这些药物未表现出接种量效应。基于在严格条件下将粪肠球菌菌株的质粒DNA与金黄色葡萄球菌的克隆青霉素酶基因进行杂交，这些耐药决定因素似乎高度同源，这表明该酶是从葡萄球菌引入链球菌的。
