Pidcock K A, Wooten J A, Daley B A, Stull T L
Department of Pediatrics, Medical College of Pennsylvania, Philadelphia 19129.
Infect Immun. 1988 Apr;56(4):721-5. doi: 10.1128/iai.56.4.721-725.1988.
The mechanisms for acquisition of iron by Haemophilus influenzae and their role in pathogenesis are not known. Heme and nonheme sources of iron were evaluated for their effect on growth of type b and nontypable strains of H. influenzae in an iron-restricted, defined medium. All 13 strains acquired iron from heme, hemoglobin, hemoglobin-haptoglobin, and heme-hemopexin. Among nonheme sources of protein-bound iron, growth of H. influenzae was enhanced by partially saturated human transferrin but not by lactoferrin or ferritin. Purified ferrienterochelin and ferridesferrioxamine failed to provide iron to H. influenzae, and the supernatants of H. influenzae E1a grown in iron-restricted medium failed to enhance iron-restricted growth of siderophore-dependent strains of Escherichia coli, Salmonella typhimurium, and Arthrobacter terregens. Marked alterations in the profile of outer membrane proteins of H. influenzae were observed when the level of free iron was varied between 1 microM and 1 mM. Catechols were not detected in the supernatants of strain E1a; however, iron-related hydroxamate production was detected by two biochemical assays. We conclude that the sources of iron for H. influenzae are diverse. The significance of hydroxamate production and iron-related outer membrane proteins to H. influenzae iron acquisition is not yet clear.
流感嗜血杆菌获取铁的机制及其在发病机制中的作用尚不清楚。在铁限制的限定培养基中，评估了血红素和非血红素铁源对b型和不可分型流感嗜血杆菌菌株生长的影响。所有13株菌株均可从血红素、血红蛋白、血红蛋白-结合珠蛋白和血红素-血红素结合蛋白中获取铁。在非血红素结合铁源中，部分饱和的人转铁蛋白可促进流感嗜血杆菌生长，而乳铁蛋白或铁蛋白则无此作用。纯化的肠螯合铁和去铁胺不能为流感嗜血杆菌提供铁，在铁限制培养基中生长的流感嗜血杆菌E1a的上清液不能促进铁载体依赖性大肠杆菌、鼠伤寒沙门氏菌和土壤节杆菌在铁限制条件下的生长。当游离铁水平在1 microM至1 mM之间变化时，观察到流感嗜血杆菌外膜蛋白谱有明显改变。在菌株E1a的上清液中未检测到儿茶酚；然而，通过两种生化测定法检测到了与铁相关的异羟肟酸产生。我们得出结论，流感嗜血杆菌的铁源多种多样。异羟肟酸产生和与铁相关的外膜蛋白对流感嗜血杆菌获取铁的意义尚不清楚。
