Opal S M, Cross A S, Gemski P, Lyhte L W
Infectious Diseases Division, Memorial Hospital of Rhode Island, Brown University Program in Medicine, Providence, RI 02860.
J Infect Dis. 1990 Apr;161(4):794-6. doi: 10.1093/infdis/161.4.794.
Because iron acquisition is essential to the survival of invasive strains of Escherichia coli, the frequency of two potential iron acquisition systems, aerobactin and hemolysin production, were compared in E. coli isolated from human blood (n = 95), urine (n = 100), and stool (n = 50). By phenotypic and genotypic methods, the prevalence of hemolysin production was 22% in bacteremic, 38% in urinary, and 22% in fecal isolates of E. coli. Aerobactin production was detected in 76% of blood and in 73% of urinary isolates but in only 52% of fecal isolates (P less than .01). A reciprocal relationship was found in blood isolates between aerobactin and hemolysin; the majority of blood isolates (55%) that lacked aerobactin were hemolytic, whereas only 14% of blood isolates that expressed aerobactin were hemolytic (P less than .0001). Aerobactin may be the principal mechanism of iron acquisition in extraintestinal isolates of E. coli, and hemolysin may serve as an alternative mechanism in the absence of aerobactin genes.
由于获取铁对于大肠杆菌侵袭性菌株的生存至关重要，因此对从人血（n = 95）、尿液（n = 100）和粪便（n = 50）中分离出的大肠杆菌中两种潜在的铁获取系统——气杆菌素产生和溶血素产生的频率进行了比较。通过表型和基因型方法，溶血素产生在大肠杆菌的血行感染分离株中的发生率为22%，在尿液分离株中为38%，在粪便分离株中为22%。在76%的血行感染分离株和73%的尿液分离株中检测到气杆菌素产生，但在粪便分离株中仅为52%（P<0.01）。在血行感染分离株中发现气杆菌素和溶血素之间存在反比关系；大多数缺乏气杆菌素的血行感染分离株（55%）具有溶血能力，而表达气杆菌素的血行感染分离株中只有14%具有溶血能力（P<0.0001）。气杆菌素可能是大肠杆菌肠外分离株获取铁的主要机制，而在缺乏气杆菌素基因的情况下，溶血素可能作为一种替代机制。
