Institute of Environmental and Animal Hygiene and Veterinary Medicine, University of Hohenheim, Garbenstrasse 30, 70599-Stuttgart, Germany.
Vet Microbiol. 2012 Nov 9;160(1-2):227-32. doi: 10.1016/j.vetmic.2012.05.022. Epub 2012 May 26.
Mycoplasma suis belongs to haemotrophic mycoplasmas (HMs) which cause infectious anaemia in a large variety of mammals. To date, no in vitro cultivation system for M. suis or other HMs has been established. We hypothesised that M. suis could grow in classical Mycoplasma media supplemented with nutrients (e.g. glucose, iron-binding proteins) which are naturally available from its host environment, the porcine blood. Blood from experimentally M. suis-infected pigs was used to inoculate either standard SP-4 Mycoplasma medium supplemented with iron-binding proteins (transferrin, haemin, and haemoglobin) or glucose-enriched Hayflick Mycoplasma medium. A quantitative M. suis-specific real-time PCR assay was applied to determine and quantify M. suis loads weekly during 12 week-incubation. The first 2 weeks after inoculation M. suis loads decreased remarkably and then persisted at a stationary level over the observation time of 12 weeks in iron-binding protein- or glucose supplemented media variants. Scanning electron microscopic analysis of liquid M. suis sub-cultures on Hayflick agar showed small, densely-packed microcolonies of irregular M. suis cells of reduced size (0.2-0.6μm) indicating nanotransformation. The partial 16S rDNA sequence of these cultured M. suis nanocells was 99.9% identical to M. suis. M. suis cells derived from liquid cultures interact in vitro with porcine erythrocytes by fibril-like structures. We conclude, that the modified Mycoplasma media used for M. suis cultivation are obviously unfavourable for growth but lead to culture persistence. M. suis adapt to inappropriate culture conditions by alteration into nanoforms.
猪肺炎支原体属于血源支原体（HMs），可引起多种哺乳动物的传染性贫血。迄今为止，尚未建立猪肺炎支原体或其他 HMs 的体外培养系统。我们假设猪肺炎支原体可以在经典的支原体培养基中生长，该培养基中添加了宿主环境（猪血液）中天然存在的营养物质（例如葡萄糖、铁结合蛋白）。将来自实验感染猪肺炎支原体的血液接种到补充有铁结合蛋白（转铁蛋白、血红素和血红蛋白）或富含葡萄糖的 Hayflick 支原体培养基的标准 SP-4 支原体培养基中。应用定量猪肺炎支原体实时 PCR 检测方法每周检测和定量 M. suis 负荷，持续 12 周孵育。接种后前 2 周，M. suis 负荷显著下降，然后在铁结合蛋白或葡萄糖补充培养基变体的 12 周观察时间内保持稳定水平。Hayflick 琼脂上液体猪肺炎支原体亚培养的扫描电子显微镜分析显示，小而密集的不规则猪肺炎支原体细胞微菌落，大小减小（0.2-0.6μm），表明发生纳米转化。这些培养的猪肺炎支原体纳米细胞的部分 16S rDNA 序列与猪肺炎支原体完全相同。源自液体培养的猪肺炎支原体细胞在体外通过纤维状结构与猪红细胞相互作用。我们得出结论，用于猪肺炎支原体培养的改良支原体培养基显然不利于生长，但会导致培养物持续存在。猪肺炎支原体通过改变为纳米形式适应不合适的培养条件。
