BACKGROUND Pneumococcus is exposed to a variety of temperature and oxygen levels in the upper respiratory tract and as it invades the lung, tissues, and blood. We sought to determine the effect of environmental variability on growth in vitro and to assess variability between strains. We evaluated the effect of temperature and oxygen on the growth of 256 isolates representing 53 serotypes, recovered from healthy carriers and disease patients. Strains were grown at a range of temperatures, anaerobically or in ambient air with catalase, and were monitored by reading the optical density. Regression models evaluated variation in the characteristics of the growth curves. RESULTS Most isolates grew to the maximal density at low temperatures (~33C) and under aerobic conditions. There was considerable variability between strains, and some of this variability was linked to serotype. However, capsule-switch experiments suggest that the production of different capsules might not be sufficient to explain this variation, suggesting there could be interactions between the capsule and genetic background. CONCLUSIONS Pneumococcal strains vary in how they respond to environmental variations, some of this variation can be explained by the capsule type being produced, but capsule production itself is not sufficient to explain the variability. This variability could help to explain why different lineages of pneumococcus are more common in carriage or disease.

中文翻译：

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肺炎球菌生长特性随环境条件的变化。

背景技术肺炎球菌暴露于上呼吸道中的各种温度和氧气水平下，并侵袭肺，组织和血液。我们试图确定环境变异性对体外生长的影响，并评估菌株之间的变异性。我们评估了温度和氧气对从健康携带者和疾病患者中回收的代表53种血清型的256个分离株生长的影响。菌株在一定范围的温度下（厌氧或在过氧化氢酶的环境空气中）生长，并通过读取光密度进行监测。回归模型评估了生长曲线特征的变化。结果大多数分离株在低温（〜33C）和有氧条件下生长到最大密度。菌株之间的差异很大，而且这种变异性与血清型有关。但是，胶囊转换实验表明产生不同的胶囊可能不足以解释这种变异，这表明胶囊和遗传背景之间可能存在相互作用。结论肺炎球菌菌株对环境变化的反应方式各不相同，其中一些这种变化可以通过生产的胶囊类型来解释，但胶囊生产本身不足以解释变异性。这种变异性可以帮助解释为什么肺炎球菌的不同谱系在运输或疾病中更为常见。提示胶囊和遗传背景之间可能存在相互作用。结论肺炎球菌菌株对环境变化的反应方式各不相同，其中一些这种变化可以通过生产的胶囊类型来解释，但胶囊生产本身不足以解释变异性。这种变异性可以帮助解释为什么肺炎球菌的不同谱系在运输或疾病中更为常见。提示胶囊和遗传背景之间可能存在相互作用。结论肺炎球菌菌株对环境变化的反应方式各不相同，其中一些这种变化可以通过生产的胶囊类型来解释，但胶囊生产本身不足以解释变异性。这种变异性可以帮助解释为什么肺炎球菌的不同谱系在运输或疾病中更为常见。