Arnold R R, Brewer M, Gauthier J J
Infect Immun. 1980 Jun;28(3):893-8. doi: 10.1128/iai.28.3.893-898.1980.
Lactoferrin is an iron-binding protein that has been detected in secretions that bathe human mucosal tissues. Previous studies have shown that, when this protein is in the iron-free state, it is capable of a direct bactericidal effect on Streptococcus mutans and Vibrio cholerae. The present study demonstrates variable susceptibilities for a variety of different microorganisms. The list of susceptible organisms includes gram-positive and gram-negative microbes, rods and cocci, facultative anaerobes, and aerotolerant anaerobes. Similar morphological and physiological types are represented among the lalctoferrin-resistant bacteria. S. mutans was more resistant to lactoferrin when grown on a sucrose-contaning medium than when it was grown on brain heart infusion broth without added scurose. When a lactoferrin-sensitive, avirulent strain of Streptococcus pneumoniae was passed through mice, the resultant virulent culture became lactoferrin resistant. Since organisms of the same species and even of the same strain (S. pneumoniae) can differ in susceptibility to lactoferrin, it appears that accessibility to the lactoferrin target site may account for differences in susceptibility. It appears that there may be a relation between virulence and resistance to lactoferrin.
乳铁蛋白是一种铁结合蛋白，已在覆盖人体黏膜组织的分泌物中被检测到。先前的研究表明，当这种蛋白处于无铁状态时，它能够对变形链球菌和霍乱弧菌产生直接杀菌作用。本研究证明了多种不同微生物对乳铁蛋白的敏感性存在差异。敏感微生物列表包括革兰氏阳性菌和革兰氏阴性菌、杆菌和球菌、兼性厌氧菌以及耐氧厌氧菌。在对乳铁蛋白耐药的细菌中也存在相似的形态和生理类型。与在未添加蔗糖的脑心浸液肉汤中培养相比，变形链球菌在含蔗糖培养基上生长时对乳铁蛋白的耐药性更强。当对乳铁蛋白敏感的无毒肺炎链球菌菌株通过小鼠传代后，产生的有毒培养物变得对乳铁蛋白耐药。由于同一物种甚至同一菌株（肺炎链球菌）的微生物对乳铁蛋白的敏感性可能不同，因此乳铁蛋白靶位点的可及性似乎可以解释敏感性的差异。毒力与对乳铁蛋白的耐药性之间似乎可能存在关联。
