McCutchan J A, Wunderlich A, Braude A I
Infect Immun. 1977 Jan;15(1):149-55. doi: 10.1128/iai.15.1.149-155.1977.
Natural resistance of the male urethra to gonococci has not been explained by classical immune mechanisms but could result from antibacterial properties of urine. Accordingly, we measured survival in midmorning urine of 10(7) F-62 T2 gonococci per ml by serial dilutions and plate counts. Fifteen killer urines from eight people all killed greater than 3 logs (average, 5.3), and 13 of 15 were sterilized. Fourteen nonkiller (inhibitor) urines from seven subjects allowed no growth. Killer urines were more acidic (pH 5.4 versus 6.4) and more concentrated (861 versus 717 mosmol/kg) than nonkillers. Upon addition of hydrogen ion, urea, and sodium chloride to urines and broth, pH proved to be the major killing factor, but urea and NaCl were also bactericidal. Susceptibility to urine bactericidal power did not vary with colony type (T2 versus T4) or strain (F-62 versus two fresh isolates). Killing was rapid (0.5 to 3 h) and not bacteriolytic. Escherichia coli multiplied 10-fold in urines that inhibited growth of gonococci. Thus, the bacteriostatic effect of urine may explain why gonococci do not infect the bladder and kidney during gonorrhea. The bactericidal properties of urine may contribute to resistance against gonococcal urethritis.
男性尿道对淋球菌的天然抵抗力并非由经典免疫机制所解释，而可能源于尿液的抗菌特性。因此，我们通过连续稀释和平板计数来测定每毫升含有10⁷F-62 T2淋球菌的晨尿中的存活率。来自8个人的15份杀菌尿液均杀死了超过3个对数（平均为5.3），且15份中有13份被灭菌。来自7名受试者的14份非杀菌（抑制性）尿液未出现细菌生长。杀菌尿液比非杀菌尿液酸性更强（pH值分别为5.4和6.4）且浓度更高（分别为861和717毫摩尔/千克）。向尿液和肉汤中添加氢离子、尿素和氯化钠后，pH值被证明是主要的杀菌因素，但尿素和氯化钠也具有杀菌作用。淋球菌对尿液杀菌能力的敏感性并不因菌落类型（T2与T4）或菌株（F-62与两个新鲜分离株）而有所不同。杀菌过程迅速（0.5至3小时）且非溶菌性。大肠杆菌在抑制淋球菌生长的尿液中繁殖了10倍。因此，尿液的抑菌作用可能解释了为什么淋病期间淋球菌不会感染膀胱和肾脏。尿液的杀菌特性可能有助于抵抗淋菌性尿道炎。
