双培养法提高涂片阴性分枝杆菌检出率的回顾性研究

 目的 探讨双培养法对提高涂片阴性分枝杆菌检出率的应用价值。方法 收集某院2019年1月-2021年9月送检住院首诊患者的普筛标本，并按固体培养、液体培养、固-液双培养进行分组。另选取涂片分枝杆菌阴性，固体、液体或固-液双培养阳性的患者，将其按送检标本部位分为肺分枝杆菌组和肺外分枝杆菌组，分析两组患者的临床特征。结果 共调查涂片阴性患者6 492例，其中固体组3 234例，液体组1 938例，双培养组1 320例，253例培养阳性，检出率3.90%，固体组、液体组、双培养组培养阳性检出率分别为2.35%（76例）、4.54%（88例）、6.74%（89例）；肺分枝杆菌检出率分别为3.11%、6.02%、7.13%，肺外分枝杆菌检出率分别为1.02%、2.68%、6.09%。253例涂片阴性培养阳性的患者中男性143例、女性110例；平均年龄（58.34±18.47）岁；检出时间中位数分别为34.65、10.45、9.89 d。肺分枝杆菌组中男性、咳嗽咳痰、呼吸道基础疾病、胸部CT有炎性渗出、结核感染T细胞斑点试验结果阳性所占比例较肺外分枝杆菌组高，差异均有统计学意义（均P<0.05）。固-液体双培养组肺外分枝杆菌检出率较固体组、液体组培养高（均P<0.001），固-液体双培养组肺分枝杆菌检出率较固体组高（P<0.001）。结论 肺结核患者伴有咳嗽咳痰、呼吸道疾病、胸部CT炎性渗出等特征，而肺外结核无典型特征。肺外结核的临床体征较肺结核隐匿，易漏诊，而固-液双培养法可以在优化标本前处理及工作流程方面提高分枝杆菌的检出率。

Retrospective study on double culture method to improve the detection rate of smear-negative Mycobacterium

Objective To explore the application value of double culture method in improving the detection rate of smear-negative Mycobacterium. Methods The screened specimens of patients with the initial diagnosis in a hospital from January 2019 to September 2021 were collected and grouped according to solid culture, liquid culture and solid-liquid double culture. In addition, patients with smear-negative Mycobacterium, positive solid, positive liquid or positive solid-liquid double culture were selected, they were divided into pulmonary Mycobacterium (PM) group and extrapulmonary Mycobacterium (EPM) group according to specimen sites, clinical characteristics of two groups of patients were analyzed. Results A total of 6 492 smear-negative patients were surveyed, 3 234 were in solid group, 1 938 in liquid group and 1 320 in double culture group, 253 patients (3.90%) were positive for culture, positive culture detection rates of patients in solid culture, liquid culture and solid-liquid double culture group were 2.35% (n=76), 4.54% (n=88) and 6.74% (n=89) respectively; detection rates of PM were 3.11%, 6.02% and 7.13% respectively, detection rates of EPM were 1.02%, 2.68% and 6.09% respectively. Among 253 smear-negative but culture positive patients, 143 were male and 110 were female; the mean age was (58.34±18.47) years; the median detection time were 34.65, 10.45 and 9.89 days respectively. Among patients in PM group, the proportion of male patients, cough and expectoration, underlying respiratory diseases, inflammatory exudation showed on chest CT, positive results of tuberculosis T cell spot test were all higher than EPM group, differences were all significant (all P < 0.05). Positive detection rate of EPM of solid-liquid double culture group was higher than solid and liquid groups (both P < 0.001), positive detection rate of PM in solid-liquid double culture group was higher than solid culture group (P < 0.001). Conclusion Patients with PM have the characteristics of cough and expectoration, respiratory diseases, inflammatory exudation on chest CT, while patients with EPM have no typical characteristics. Clinical signs of EPM are more concealed than that of PM, and it is easy to miss diagnosis, solid-liquid double culture method can improve the detection rate of Mycobacterium in optimizing the sample pre-treatment and workflow.