西安市134例百日咳疑似病例不同标本百日咳鲍特菌检测阳性率比较

Comparison of Bordetella pertussis positivity rates in different types of specimens from 134 suspected pertussis cases in Xi’an city

目的比较百日咳疑似病例鼻、咽和鼻咽拭子标本百日咳鲍特菌(Bordetella pertussis,Bp)检测阳性率。方法选择西安市两家医院2018年1-7月134例百日咳疑似病例,同时采集鼻、咽和鼻咽拭子标本,进行Bp分离培养和实时荧光定量聚合酶链反应核酸检测。结果百日咳疑似病例的Bp检测总阳性率为44.78%(60/134),其中鼻、咽、鼻咽拭子阳性率分别为36.57%、32.09%、39.55%(χ^(2)=1.64,P=0.440);发病后0-7d、8-14d、15-21d、22-28d、29d采样的阳性率分别为23.33%、64.52%、63.89%、42.86%、23.33%(χ^(2)=22.13,P=0.000)。鼻、咽、鼻咽拭子Bp核酸检测阳性率分别为36.57%、32.09%、39.55%(χ^(2)=1.64,P=0.440);分离培养阳性率分别为0.00%、0.00%、4.59%(Fisher精确概率法,P=0.036)。在Bp核酸阳性病例中鼻和/或咽、鼻和/或鼻咽、咽和/或鼻咽拭子阳性分别占93.33%、91.67%、100%(Fisher精确概率法,P=0.080)。结论百日咳疑似病例鼻、咽和鼻咽拭子Bp检测总阳性率相当;核酸检测阳性率以鼻咽拭子最高,组合采样可提高Bp核酸检测阳性率;分离培养仍建议选择鼻咽拭子。

Objective To compare positivity rates of Bordetella pertussis(Bp) in nasal, throat, and nasopharyngeal swabs obtained from suspected pertussis cases.Methods We selected 134 suspected pertussis cases from two hospitals of Xi’an city from January to July 2018 and obtained result from nasal, throat, and nasopharyngeal swabs for detection of Bp by isolation and culture and by real-time fluorescence quantitative polymerase chain reaction.Results The overall Bp positivity rate among suspected pertussis cases was 44.78%(60/134);positivity rates in nasal, throat, and nasopharyngeal swabs were 36.57%, 32.09%, and 39.55%, respectively(χ2=1.64, P=0.440). Positivity rates for samples collected at 0-7, 8-14, 15-21, 22-28, and ≥29 days since onset were 23.33%, 64.52%, 63.89%, 42.86%, and 23.33%(χ2=22.13, P=0.000). Positivity rates of Bp nucleic acid in nasal, throat, and nasopharyngeal swabs were 36.57%, 32.09%, and 39.55%(χ2=1.64, P=0.440). Positivity rates from Bp isolation and culture in the three swabs were 0.00%, 0.00%, and 4.59%(Fisher’s exact test, P=0.036). In the Bp nucleic acid-positive cases, 93.33%, 91.67%, and 100% were positive in nasal and/or throat, nasal and/or nasopharyngeal, and throat and/or nasopharyngeal swabs, respectively(Fisher’s exact test, P=0.080).Conclusions The overall positivity rates of Bp in nasal, throat, and nasopharyngeal swabs of suspected pertussis cases were comparable, with Bp nucleic acid positivity being higher in nasopharyngeal swabs and combination samples. We continue to recommend nasopharyngeal swabs for isolation and culture.