Investigation of oxacillin-hydrolyzing beta-lactamase in borderline methicillin-resistant clinical isolates of Staphylococcus aureus
Investigation of oxacillin-hydrolyzing beta-lactamase in borderline methicillin-resistant clinical isolates of Staphylococcus aureus
复制标题
DOI：
10.1159/000048528
复制
发表时间：
2001-07-01
期刊：
影响因子：
3.3
通讯作者：
Szabó, I
中科院分区：
文献类型：
--
作者：
Gál, Z;Kovács, P;Szabó, I
背景：金黄色葡萄球菌对耐青霉菌酶青霉素（PRPs）的临界耐药机制可能包括经典青霉素酶的过量产生和/或β -内酰胺酶水解PRPs的产生。方法：以枯草芽孢杆菌为试验菌株，用分光光度法测定全细胞和纯化酶的β -内酰胺酶活性，并在分离的细胞质膜上进行生物测定。结果：在53株金黄色葡萄球菌的临床分离株中，18株的oxacillin MIC值为0.5 ~ 2马克/毫升，在4株产生大量可诱导的A型β -内酰胺酶的情况下，舒巴坦和/或克拉维酸降低了该值。从这些菌株分离的细胞质膜显示出oxacillin水解活性。其中一种菌株也在球霉素存在下生长，球霉素是一种已知会干扰膜脂蛋白锚定的抗生素；这种处理消除了oxacillin水解活性。结论：这些菌株的耐药性是由一种具有氧西林水解活性的膜结合脂蛋白引起的。版权所有(C) 2001 s.k ager AG，巴塞尔。
Background: Mechanisms of borderline resistance of Staphylococcus aureus to penicillinase-resistant penicillins (PRPs) may include hyperproduction of classical penicillinase and/or production of beta -lactamase hydrolyzing also PRPs, Methods: beta -Lactamase activity of whole cells and purified enzymes was estimated spectrophotometrically and in isolated cytoplasmic membranes by bioassay with Bacillus subtilis as test strain. Results: Out of 53 clinical isolates of S. aureus, 18 showed oxacillin MIC values from 0.5 to 2 mug/ml, which were reduced by sulbactam and/or clavulanic acid in the case of four isolates producing large quantities of inducible, type A beta -lactamase. Cytoplasmic membranes isolated from these strains showed oxacillin-hydrolyzing activity. One of these strains was grown also in the presence of globomycin, an antibiotic known to interfere with the anchorage of membrane lipoproteins; this treatment eliminated the oxacillin-hydrolyzing activity. Conclusions: The resistance in these strains was due to a membrane-bound lipoprotein with oxacillin-hydrolyzing activity. Copyright (C) 2001 S.Karger AG,Basel.