Gargan R A, Brumfitt W, Hamilton-Miller J M
Department of Medical Microbiology, Royal Free Hospital and School of Medicine, Hampstead, London.
J Med Microbiol. 1991 Jul;35(1):12-7. doi: 10.1099/00222615-35-1-12.
Tests of phagocytosis and killing by polymorphonuclear neutrophil leucocytes (PMNL) are usually done with pre-opsonised organisms. Phagocytosis of 11 strains of Escherichia coli, pre-opsonised, and in the stationary phase, resulted in the killing of only one strain although all the organisms were phagocytosed. However, when the same strains were added unopsonised to a PMNL-serum mixture, eight were killed after phagocytosis. With two of these strains, the amount of killing was inversely proportional to the time of pre-oposonisation. E. coli incubated for 30 min in dilute peptone water in Hanks's Balanced Salts Solution before phagocytosis also became resistant to killing; bacterial division did not occur during this period. Experiments with bacteria in urine confirmed these findings and showed that E. coli exposed to serum or urine before phagocytosis became resistant to killing by PMNL. E. coli rapidly changes its sensitivity to phagolysosome killing during transition from stationary to lag phase in a nutrient medium. This resistance is retained through the exponential phase but is lost during the stationary phase. The killing of Pseudomonas, Enterobacter, and Acinetobacter by PMNL was unaffected by varying the method of opsonisation or the phase of growth. If this phenomenon occurs in vivo it may affect the outcome of infections caused by strains of E. coli that survive killing by PMNL.
多形核中性粒细胞（PMNL）的吞噬作用和杀菌作用测试通常使用预先调理过的微生物进行。对11株处于稳定期且预先调理过的大肠杆菌进行吞噬作用测试，结果发现，尽管所有微生物都被吞噬了，但只有一株被杀死。然而，当将相同的菌株未经调理地添加到PMNL - 血清混合物中时，吞噬作用后有八株被杀死。对于其中两株菌株，杀菌量与预先调理的时间成反比。在吞噬作用前，将大肠杆菌在汉克斯平衡盐溶液中的稀蛋白胨水中孵育30分钟，其也变得对杀菌有抗性；在此期间未发生细菌分裂。对尿液中的细菌进行的实验证实了这些发现，并表明在吞噬作用前暴露于血清或尿液中的大肠杆菌对PMNL的杀菌作用变得有抗性。在营养培养基中，大肠杆菌从稳定期转变为迟缓期时，其对吞噬溶酶体杀菌的敏感性会迅速变化。这种抗性在指数期得以保留，但在稳定期会丧失。PMNL对铜绿假单胞菌、肠杆菌和不动杆菌的杀菌作用不受调理方法或生长阶段变化的影响。如果这种现象发生在体内，它可能会影响由能在PMNL杀菌作用下存活的大肠杆菌菌株引起的感染结果。
