Small colony variants (SCVs) were first described more than 100 years ago for Staphylococcus aureus and various coagulase-negative staphylococci. Two decades ago, an association between chronic staphylococcal infections and the presence of SCVs was observed. Since then, many clinical studies and observations have been published which tie recurrent, persistent staphylococcal infections, including device-associated infections, bone and tissue infections, and airway infections of cystic fibrosis patients, to this special phenotype. By their intracellular lifestyle, SCVs exhibit so-called phenotypic (or functional) resistance beyond the classical resistance mechanisms, and they can often be retrieved from therapy-refractory courses of infection. In this review, the various clinical infections where SCVs can be expected and isolated, diagnostic procedures for optimized species confirmation, and the pathogenesis of SCVs, including defined underlying molecular mechanisms and the phenotype switch phenomenon, are presented. Moreover, relevant animal models and suggested treatment regimens, as well as the requirements for future research areas, are highlighted.

中文翻译：

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持续感染中葡萄球菌小菌落变体的临床意义和发病机理。

小菌落变体（SCV）于100多年前首次被描述为金黄色葡萄球菌和各种凝固酶阴性葡萄球菌。二十年前，观察到慢性葡萄球菌感染与SCV的存在之间的关联。从那时起，已经发表了许多临床研究和观察结果，这些结果将复发性，持续性葡萄球菌感染（包括与装置相关的感染，骨骼和组织感染以及囊性纤维化患者的气道感染）与这种特殊表型联系在一起。通过其细胞内生活方式，SCV表现出超出经典耐药机制的所谓表型（或功能性）耐药性，并且通常可以从治疗难治性感染过程中获得。在这篇评论中，可以预期和分离出SCV的各种临床感染，介绍了用于优化物种确认的诊断程序，以及SCV的发病机理，包括确定的潜在分子机制和表型转换现象。此外，重点介绍了相关的动物模型和建议的治疗方案，以及对未来研究领域的要求。