重组人血小板型磷脂酶A_2对耐药菌的杀菌作用与耐药性诱导

Bactericidal Activity and Drug Resistance Induction of Recombinant Human Platelet Phospholipase A_2 on Drug-resistant Bacteria

目的探讨重组人血小板型磷脂酶A2（PLA2）的对临床分离耐药菌株的杀菌作用及其细菌耐药性，为开发新型抗菌蛋白提供重要信息。方法将不同浓度的血小板型PLA2与细菌在37℃共同孵育2h，然后加入营养琼脂平皿中，37℃培养18～20h，计每一琼脂板上的菌落形成数（CFU），计算出血小板型PLA2杀菌率；根据耐药性诱导试验，用PLA2诱导金黄色葡萄球菌，观察细菌耐药性。结果血小板型PLA2对金黄色葡萄球菌、表皮葡萄球菌、粪肠球菌的标准菌株与耐药菌株均同样具有较强的杀灭作用，对3种标准菌株的最低杀菌浓度（MBC）分别为0．81、0．1、0．2μg／ml，对耐药菌株的MBC为0．1～0．3μg／ml；连续三代诱导未见引起金黄色葡萄球菌耐药。结论血小板型PLA2对耐药的革兰阳性菌有较强的杀菌作用，其不易引起金黄色葡萄球菌耐药。

OBJECTIVE To explore the bactericidal activity of recombinant human platelet phospholipase A2 （PLA2） on drug-resistant bacteria and drug resistance of Staphylococcus aureus induced by PLA2. METHODS The bacterial solution with different concentration of the PLA2 was incubated at 37 ℃ for 2 hours in a water bath. Then the reactive solution poured on agar plates and grew the bacteria in 37℃ for 18-20 hours. The colony formed unit （CFU） was counted and the bactericidal rate of PLA2 was calculated. The drug resistance of S. aureus induced by the PLA2 was observed. RESULTS The PLA2 possessed strong bactericidal activity against Gram-positive（G^＋） bacteria and drug-resistant bacteria. The MBC of S. aureus, Staphylococcus epiderrnidis, Enterococcus facecalis were 0. 81, 0. 1 and 0. 2 μg/ml respectively, and the minimal bactericidal concenration （MBC） of their drug-resistant bacteria was 0.1-0.3 μg/ml. The platelet PLA2 could not induce Staphylococcus into drug-resistant bacteria after three passages. CONCLUSIONS The recombinant human platelet PLA2 possesses potent bactericidal activity against drug-resistant G^＋ bacteria. PLA2 is not easy to induce drug resistance for Staphylococcus.