Phenotypic variants of staphylococci and their underlying population distributions following exposure to stress.
Phenotypic variants of staphylococci and their underlying population distributions following exposure to stress.
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DOI：
10.1371/journal.pone.0077614
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Gottfries J
中科院分区：
文献类型：
--
作者：
Onyango LA;Hugh Dunstan R;Roberts TK;Macdonald MM;Gottfries J
本研究调查了环境条件的改变是否会诱导金黄色葡萄球菌小菌落变异表型 (SCV) 的形成以及细胞形态和超微结构的相关变化。表皮和路邓沙门氏菌。野生型临床分离株暴露于低温 (4°C)、抗生素应激（青霉素 G 和万古霉素；0-10,000 µg mL-1）、pH 应激（pH 3-9）和渗透压挑战（NaCl 浓度为 0-20%）。通过扫描和透射电子显微镜（SEM 和 TEM）评估细胞直径、细胞壁厚度和群体分布变化（n≥300）的变化，并与对照群体进行比较。我们的分析发现，长期暴露于所有治疗会导致随后形成 SCV 表型。观察到的 SCV 表现为溶血和色素沉着减少（氯化钠、pH 和 4°C 处理）或完全缺乏（抗生素处理）的微小集落。 SEM 比较分析显示，除了金黄色葡萄球菌和表皮葡萄球菌 10% NaCl 以及表皮葡萄球菌 4°C 之外，SCV 群体的细胞尺寸明显更小 (p<0.05)。表皮葡萄球菌和路邓葡萄球菌中出现的较小细胞的不同亚群也观察到了种群分布模式的变化。 TEM 分析显示，除了暴露于 4°C 的路邓沙门氏菌外，所有处理和物种的细胞壁均显着增厚。这些发现表明葡萄球菌通过改变细胞大小和壁厚度来适应环境压力，这可能代表了改变表型的形成，从而促进了在恶劣条件下的生存。表型反应受普遍环境应激机制类型的控制，导致超微结构和大小的适当改变，表明基因表达、蛋白质组和代谢组的下游变化。
This study investigated whether alterations in environmental conditions would induce the formation of small colony variant phenotypes (SCV) with associated changes in cell morphology and ultra-structure in S. aureus, s. epidermidis, and S. lugdunensis. Wild-type clinical isolates were exposed to low temperature (4°C), antibiotic stress (penicillin G and vancomycin; 0-10,000 µg mL-1), pH stress (pH 3-9) and osmotic challenge (NaCl concentrations of 0-20%). Changes in cell diameter, cell-wall thickness, and population distribution changes (n ≥ 300) were assessed via scanning and transmission electron microscopy (SEM and TEM), and compared to control populations. Our analyses found that prolonged exposure to all treatments resulted in the subsequent formation of SCV phenotypes. Observed SCVs manifested as minute colonies with reduced haemolysis and pigmentation (NaCl, pH and 4°C treatments), or complete lack thereof (antibiotic treatments). SEM comparison analyses revealed significantly smaller cell sizes for SCV populations except in S. aureus and S. epidermidis 10% NaCl, and S. epidermidis 4°C (p<0.05). Shifts in population distribution patterns were also observed with distinct sub-populations of smaller cells appearing for S. epidermidis, and S. lugdunensis. TEM analyses revealed significantly thicker cell-walls in all treatments and species except S. lugdunensis exposed to 4°C. These findings suggest that staphylococci adapted to environmental stresses by altering their cell size and wall thickness which could represent the formation of altered phenotypes which facilitate survival under harsh conditions. The phenotypic response was governed by the type of prevailing environmental stress regime leading to appropriate alterations in ultra-structure and size, suggesting downstream changes in gene expression, the proteome, and metabolome.
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影响因子：
3.7
作者：
Onyango LA;Dunstan RH;Gottfries J;von Eiff C;Roberts TK
通讯作者：
Roberts TK
影响因子：
9.4
作者：
Kipp, F;Becker, K;von Eiff, C
通讯作者：
von Eiff, C
影响因子：
3.2
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影响因子：
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作者：
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通讯作者：
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影响因子：
4.9
作者：
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