ROTHBARD S, WATSON R F
J Exp Med. 1948 Jun 1;87(6):521-33. doi: 10.1084/jem.87.6.521.
A study was made of the variation occurring in group A streptococci during the natural course of infection in man. From 54 patients with 56 different group A streptococcal infections of the upper respiratory tract, 251 strains of streptococci, isolated at weekly intervals following infection, were tested for their capacity to resist the bacteriostatic action of normal human blood. In 52 of the infections the streptococci were of recognized serological types and were also tested for variation in their ability to produce the type-specific M protein antigen. Strains isolated in the 1st week of infection were uniformly highly resistant to bacteriostasis and elaborated large amounts of M substance. In 42 per cent of the 52 infections, strains isolated in the convalescent and carrier stages showed an increasing susceptibility to bacteriostasis correlated with a progressive loss of M substance; whereas in the remaining 58 per cent resistance to bacteriostasis and the capacity to produce M protein were maintained throughout the observation period. In 3 different infections, the streptococci became so degraded that no M protein could be demonstrated in acid extracts of these variants. Concomitantly these strains became highly susceptible to bacteriostasis. Spontaneous reversion did not occur, but serial mouse passage reestablished these functions. These degraded variants had the same T antigen as their respective original strains. No evidence was obtained that variation of group A streptococci in resistance to bacteriostasis or in the ability to produce the type-specific M antigen was associated (a) with the appearance of type-specific bacteriostatic antibodies; (b) with any particular serological type of streptococcus; (c) with the production of streptococcal proteinase which digests the M protein; (d) with the therapeutic administration of sulfadiazine; or (e) with the development of complications. The possible relationship of these observations to the problem of the "dangerous carrier" of group A hemolytic streptococci is discussed.
对A组链球菌在人类自然感染过程中的变异情况进行了研究。从54例患有56种不同的上呼吸道A组链球菌感染的患者中，在感染后每周分离出251株链球菌，检测它们抵抗正常人血液抑菌作用的能力。在52例感染中，链球菌属于已知血清型，还检测了它们产生型特异性M蛋白抗原能力的变异情况。感染第1周分离出的菌株对抑菌作用均具有高度抗性，并产生大量M物质。在52例感染中的42%，恢复期和带菌期分离出的菌株对抑菌作用的敏感性增加，与M物质的逐渐丧失相关；而在其余58%的感染中，在整个观察期内对抑菌作用的抗性和产生M蛋白的能力得以维持。在3例不同的感染中，链球菌发生了严重降解，以至于在这些变异株的酸提取物中无法检测到M蛋白。与此同时，这些菌株对抑菌作用变得高度敏感。自发回复未发生，但经连续小鼠传代后这些功能得以恢复。这些降解变异株与其各自的原始菌株具有相同的T抗原。没有证据表明A组链球菌在抑菌抗性或产生型特异性M抗原能力方面的变异与以下因素有关：(a)型特异性抑菌抗体的出现；(b)任何特定血清型的链球菌；(c)产生消化M蛋白的链球菌蛋白酶；(d)磺胺嘧啶的治疗性给药；或(e)并发症的发生。讨论了这些观察结果与A组溶血性链球菌“危险带菌者”问题的可能关系。
