Root R K, Isturiz R, Molavi A, Metcalf J A, Malech H L
J Clin Invest. 1981 Jan;67(1):247-59. doi: 10.1172/JCI110020.
Normal and antibiotic-pretreated staphylococci were incubated with human neutrophils to determine the interactions between cells and antimicrobials in the killing of the organisms. Staphylococcus aureus 502A pretreated during log-phase growth with subinhibitory ((1/4) minimum inhibiting concentration) (MIC) concentrations of penicillin G were more susceptible to killing by normal neutrophils than untreated bacteria (intracellular survival 0.17+/-0.04 vs. 1.5+/-0.38%, mean+/-SEM, respectively, at 35 min in 14 experiments; P < 0.01 by t test). Furthermore, this enhanced susceptibility to killing was observed even when phagosome formation was inhibited by cytochalasin B (65.6+/-4.6% pencillintreated vs. 30.5+/-4.5% untreated killed at 30 min in 14 experiments, P < 0.001). Pretreatment of S. aureus with vancomycin similarly enhanced susceptibility to killing by cytochalasin B-treated polymorphonuclear leukocytes (PMN), whereas pretreatment with gentamicin did not. The enchancement of killing by pretreatment with cell wall-active antibiotics was present in a dose-response fashion to 1/16th the MIC. It required specific antimicrobial activity; i.e., penicillin activity was inhibited by penicillinase or by incubation with bacteria at 4 degrees C. It also required active cellular metabolism and intact neutrophils. For antibiotic-pretreated bacteria to be killed by normal and cytochalasin B-treated cells, phagocytosis or binding to the cells was essential via a serum opsonindependent mechanism. In experiments with the cytochalasin B-treated cells, all bound penicillin-treated bacteria were killed vs. only a fraction (70%) of the bound untreated bacteria. Penicillin in 10 times the MIC had no direct effects on PMN phagocytic, metabolic, or microbicidal functions against a nonsusceptible organism, Candida albicans. The results indicate a cooperative effect between cell wall-active antibiotics at low concentrations and human PMN in the killing of staphylococci. The model establishes conditions for the study of the mechanisms involved in the cooperation of these bactericidal systems.
将正常葡萄球菌和经抗生素预处理的葡萄球菌与人中性粒细胞一起孵育，以确定细胞与抗菌药物在杀灭这些微生物过程中的相互作用。在对数生长期用亚抑制浓度（（1/4）最低抑菌浓度）（MIC）的青霉素G预处理的金黄色葡萄球菌502A比未处理的细菌更易被正常中性粒细胞杀灭（在14次实验中，35分钟时细胞内存活率分别为0.17±0.04%和1.5±0.38%，平均值±标准误；经t检验，P<0.01）。此外，即使细胞松弛素B抑制吞噬体形成，仍观察到这种增强的杀灭敏感性（在14次实验中，30分钟时，经青霉素处理的被杀死率为65.6±4.6%，未处理的为30.5±4.5%，P<0.001）。用万古霉素预处理金黄色葡萄球菌同样增强了经细胞松弛素B处理的多形核白细胞（PMN）的杀灭敏感性，而用庆大霉素预处理则没有。用细胞壁活性抗生素预处理增强杀灭作用呈剂量反应关系，直至1/16 MIC。这需要特定的抗菌活性；即青霉素活性被青霉素酶抑制或在4℃与细菌孵育时被抑制。这也需要活跃的细胞代谢和完整的中性粒细胞。为了使经抗生素预处理的细菌被正常细胞和经细胞松弛素B处理的细胞杀灭，吞噬作用或通过血清调理素非依赖性机制与细胞结合是必不可少的。在用细胞松弛素B处理的细胞进行的实验中，所有结合的经青霉素处理的细菌都被杀死，而结合的未处理细菌只有一部分（70%）被杀死。10倍MIC的青霉素对PMN针对非敏感生物体白色念珠菌的吞噬、代谢或杀菌功能没有直接影响。结果表明低浓度的细胞壁活性抗生素与人PMN在杀灭葡萄球菌方面存在协同作用。该模型为研究这些杀菌系统协同作用的机制建立了条件。
