泌尿生殖道支原体培养假性结果原因探讨

Discussion of the Reasons for the False Results of Cultivation of Mycoplasma at Urogenital Tract

目的探讨泌尿生殖道支原体培养假性结果的原因以及提高准确率的方法。方法对380例标本进行支原体液体培养法、固体平板培养法、血平板培养法检测,并对血平板上生长的菌落作脲酶和精氨酸分解试验。结果 380例标本Uu-Mh二合一液体培养有180例颜色变红呈阳性反应,而这180例标本支原体固体平板培养仅115例检出支原体,检出率仅为63.9%,在液体培养变红且未见浑浊的140例标本中,固体培养法未见支原体的有33例,而这33例标本采用血平板培养法全部有菌落生长,这些菌株的脲酶或精氨酸分解试验呈阳性。结论支原体液体培养易受分解尿素或精氨酸菌株的干扰而呈现假阳性结果,因此支原体培养应以固体平板培养结果为准。

Objective To study the reasons for the false results of cultivation of mycoplasma at urogenital tract and the methods of improving the accuracy of culture . Methods 380 specimens were cultivated for mycoplasma through liquid medium and solid agar medium. Some specimens were also cultivated on blood agar for bacteria and the urease and arginine-decomposing test on bacteria strains which grew on these blood agar were done. Results Among the 380 specimens cultivated in Uu-Mh broth medium, 180 specimens＇ medium became red,which were defined as positive results. We used solid agar medium to cultivate these 180 cases for mycoplasma , and only 115 cases were positive. The detection rate of mycoplasma through solid agar medium was only 63.9 %. Among the 140 specimens cultivated by broth medium which became red but not turbid , 33 cases showed negative results by solid agar medium cultivation for mycoplasma. Moreover, bacteria were found in all these 33 specimens when cultivated on blood agar, and the results of urease and arginine decomposing test of these colonies were all positive. Conclusion The result of broth cultivation for mycoplasma is easily influenced by bacteria strains which can decompose urea or arginine, and this will lead to false positivity. Therefore, the result of solid agar medium cultivation for mycoplasma is more accurate.