儿童肺炎支原体感染血清学与分子生物学检测方法的对比研究

Comparative study of serological and molecular biological methods for detection of pediatric Mycoplasma pneumoniae infection

目的采用血清学与分子生物学2种方法检测儿童肺炎支原体感染,进行对比研究并分析差异原因。方法连续入选因疑似呼吸道感染就诊患儿9339份血清标本,年龄0~13岁,分别采集其血清和呼吸道分泌物,用被动凝集法测定血清中肺炎支原体抗体,用多重PCR或RNA恒温扩增技术检测呼吸道分泌物中的肺炎支原体核酸。结果剔除第二份血清标本抗体滴度无变化的标本428例,共入组8911例血标本和4065例分泌物标本。在抗体检测的8911例标本中,女性抗体检出率高于男性,年龄越大抗体检出阳性率越高,门诊患者支原体抗体检出阳性率高于住院患者,秋冬季节抗体阳性检出率高于春夏季节(P<0.05);在核酸检测的4065例标本中,年龄越大支原体核酸阳性率越高,秋冬季节核酸检出阳性率高于春夏季节(P<0.05),而不同性别以及住院和门诊患者核酸阳性检出率差异无统计学意义(P>0.05)。门诊患者在抗体滴度为1∶320的占比显著高于其他滴度(14.7%,1310/8911)。以核酸检测为金标准,分别对抗体滴度为1∶160和1∶640的检测结果进行评价,结果显示:在抗体滴度为1∶640时,一致性较1∶160更好;抗体滴度为1∶640时,敏感度较1∶160降低,但特异度、准确度、阳性预测值较抗体1∶160时升高。结论对比抗体核酸检测结果确有差异,且门诊患儿或当血清滴度为1∶320时应注意结合2方法共同判定肺炎支原体感染。

Objective To compare the serological and molecular biological tests for detecting the infection of pediatric Mycoplasma pneumoniae and to analyze the causes of difference. Methods 9 339 serum samples from children with suspected respiratory tract infection were selected continuously.The patients were aged 0-13 years old.Serum and respiratory secretions from these patients were collected.The antibodies against M.pneumoniae were detected by passive agglutination,the nucleic acids of M.pneumoniae in respiratory secretions were amplified by multiplex PCR or simultaneous amplificationmethods. Results After excluding 428 second sera without altered titer,a total of 8 911 blood samples and 4 045 secretion samples were collected.Among the 8 911 specimens tested by serology assay,the detection rate of female was higher than that of males.The older the age,the higher the positive rate of antibody detection.The positive rate in outpatients was higher than that in hospitalized ones,and the positive rate was greater in spring and summer season.In the 4 065 specimens of nucleic acid detection,the older the age,the greater the positive rate.The positive rate of nucleic acid detection in autumn and winter was greater than that in spring and summer( P < 0.05),but the significance was not observed in genders and hospitalization.We analyzed the antibody titer and found that in outpatients,the proportion of 1 ∶320 titers was significantly higher than other titers(14.7%,1 310 /8 911).Using nucleic acid detection as gold standard,the results of antibody titer of 1 ∶160 and 1 ∶640 were evaluated.When the 1 ∶640 was set as positive,the consistency was better than that of 1 ∶160,although the sensitivity decreased,the specificity,accuracy and positive predictive value were all greater than that of 1 ∶160. Conclusion There were difference between antibody and nucleic acid detection methods.In outpatients or when the serum titer is 1 ∶320,two methods should be combined to determine the infection of M.pneumoniae.