Waites K B, Canupp K C
Department of Pathology, University of Alabama at Birmingham, Birmingham, Alabama 35249-7331, USA.
J Clin Microbiol. 2001 Dec;39(12):4328-31. doi: 10.1128/JCM.39.12.4328-4331.2001.
We used simulated blood cultures inoculated with clinical isolates of Mycoplasma hominis to determine whether liquid media of the BacT/ALERT (Organon Teknika, Durham, N.C.) will support growth of this fastidious organism and whether its presence can generate a positive signal with the instrument. Viability of clinical isolates of M. hominis was maintained for 7 days in BacT/ALERT media, and organisms were able to multiply when 1% gelatin was added to neutralize the mycoplasmastatic effects of the sodium polyanetholsulfonate anticoagulant. Without the addition of gelatin to BacT/ALERT bottles, the mycoplasmas declined in numbers or became completely nonviable. Mycoplasmal growth was further enhanced in BacT/ALERT PF both supplemented with gelatin, arginine, and DNA in comparison to broth with only gelatin added. No BacT/ALERT bottles containing M. hominis in simulated blood cultures were flagged positive by the instrument, despite growth of microorganisms of up to 10(7) CFU/ml after incubation for up to 7 days, suggesting that inadequate CO(2) production or some other mechanism prevents the instrument from recognizing the presence of the organism and its metabolic products. The fastidious cultivation requirements and relatively slow growth of M. hominis warrant that dependence on automated systems and techniques designed to detect conventional bacteria will not be reliable for recovery of M. hominis and that specialized media and incubation conditions designed for optimum cultivation of mycoplasmas should be employed when this organism is suspected on clinical grounds.
我们使用接种人型支原体临床分离株的模拟血培养物，来确定BacT/ALERT（Organon Teknika公司，北卡罗来纳州达勒姆）的液体培养基是否能支持这种苛求菌的生长，以及该菌的存在能否使仪器产生阳性信号。人型支原体临床分离株在BacT/ALERT培养基中可保持活力7天，当添加1%明胶以中和多聚茴香脑磺酸钠抗凝剂的支原体抑制作用时，该菌能够增殖。如果不向BacT/ALERT瓶中添加明胶，支原体数量会减少或完全失去活力。与仅添加明胶的肉汤相比，添加了明胶、精氨酸和DNA的BacT/ALERT PF培养基能进一步促进支原体生长。在模拟血培养中，尽管孵育长达7天后微生物生长至高达10(7) CFU/ml，但含有M. hominis的BacT/ALERT瓶均未被仪器判定为阳性，这表明二氧化碳产生不足或其他某种机制阻止了仪器识别该菌及其代谢产物的存在。人型支原体苛刻的培养要求和相对缓慢的生长速度意味着，依赖用于检测传统细菌的自动化系统和技术来分离人型支原体并不可靠，当临床上怀疑有该菌时，应采用专门为支原体最佳培养设计的培养基和孵育条件。
