von Eiff C, Proctor R A, Peters G
Institut für Medizinische Mikrobiologie, Westfälische Wilhelms-Universität, Münster, Germany.
Int J Clin Pract Suppl. 2000 Dec(115):44-9.
S. aureus small-colony variants are a naturally occurring subpopulation which grow slowly and produce small colonies on routine media. They also demonstrate a number of other characteristics that are atypical for S. aureus including reduced alpha-toxin production and delayed coagulase activity. The connection of S. aureus SCVs with persistent and relapsing infections has been defined over the past decade, especially in patients with chronic osteomyelitis and in cystic fibrosis patients as demonstrated by prospective studies. While the studies with clinical isolates of SCVs suggested a link between electron transport-defective strains and persistent infections, a defined hemB mutant with the SCV phenotype provided strong additional evidence for these connections. The hemB mutant was phagocytosed by cultured endothelial cells, but did not lyse these cells, because the mutant produced very little alpha-toxin. The intracellular location may shield the SCVs from host defenses and antibiotics, thus providing one explanation for the difficulty in clearing S. aureus SCVs from host tissues.
金黄色葡萄球菌小菌落变异株是一种自然存在的亚群，其生长缓慢，在常规培养基上形成小菌落。它们还表现出许多其他非典型的金黄色葡萄球菌特征，包括α-毒素产生减少和凝固酶活性延迟。在过去十年中，金黄色葡萄球菌小菌落变异株与持续性和复发性感染之间的联系已得到明确，前瞻性研究表明，在慢性骨髓炎患者和囊性纤维化患者中尤为如此。虽然对小菌落变异株临床分离株的研究表明电子传递缺陷菌株与持续性感染之间存在联系，但具有小菌落变异株表型的明确hemB突变体为这些联系提供了有力的额外证据。hemB突变体被培养的内皮细胞吞噬，但不会裂解这些细胞，因为该突变体产生的α-毒素非常少。细胞内定位可能使小菌落变异株免受宿主防御和抗生素的影响，从而为从宿主组织中清除金黄色葡萄球菌小菌落变异株的困难提供了一种解释。
