超声分散技术在分枝杆菌液体培养污染再处理中的应用效果分析

目的:评估超声分散技术在分枝杆菌液体培养污染标本再处理中的应用效果。方法:对山东省公共卫生临床中心门诊和住院收治的4490例疑似肺结核和795例确诊肺结核患者的痰标本进行液体培养，观察痰培养阳性率、污染率以及报告污染时间。将报告污染的MGIT培养管内容物充分混匀，并将其平均分为两份标本，一份纳入直接组(259例),另一份纳入超声组(259例),两组分别应用直接处理法和超声分散法进行污染标本的再处理。观察两组再处理后培养阳性率和污染率，并比较两组结核分枝杆菌复合群(Mycobacterium tuberculosis complex, MTBC)与非结核分枝杆菌(nontuberculous mycobacteria, NTM)的检出率。结果:5285例患者痰标本培养阳性率为17.7%(935/5285),污染率为4.9%(259/5285)。157例(60.6%)患者的培养污染报告时间为1～3 d, 100例(38.6%)报告时间为4～10 d, 2例(0.8%)为11～20 d。直接组与超声组阳性率分别为7.3%(19/259)和13.9%(36/259);污染率分别为26.6%(6...

Study on the application effect of ultrasonic dispersion technique in the reprocessing of contaminated mycobacterium liquid cultures

Objective: Study on the application effect of ultrasonic dispersion technique in the reprocessing of mycobacterium liquid culture contaminated specimens. Methods: Sputum samples of 4490 suspected tuberculosis patients and 795 confirmed tuberculosis patients admitted to the Outpatient and Inpatient Departments of Shandong Public Health Clinical Center were subjected to initial liquid culture, and the positive rate, contamination rate and reporting time of contamination were observed. Among them, there were 259 cases of culture contamination. The liquid culture of every contaminated specimen was thoroughly mixed and divided into two samples, one was reprocessed directly, and the other was reprocessed by ultrasound dispersion method. The positive rate and contamination rate in groups using the two methods were observed, and the detection rate of Mycobacterium tuberculosis complex (MTBC) and nontuberculous mycobacteria (NTM) were compared. Results: The positive rate of primary culture of 5285 sputum specimens was 17.7% (935/5285), and the contamination rate was 4.9% (259/5285). Among the 259 contaminated samples, 157 cases (60.6%) reported contamination time within 1-3 days, 100 cases (38.6%) within 4-10 days, 2 cases (0.8%) within 11-20 days. The positive rates of direct group and ultrasonic group were 7.3% (19/259) and 13.9% (36/259), respectively; contamination rates were 26.6% (69/259) and 21.2% (55/259); MTBC detection rates were 4.2% (11/259) and 5.0% (13/259); NTM detection rates were 3.1% (8/259) and 8.9% (23/259), respectively. Comparing the culture positive rate between the two groups, the ultrasound group was statistically higher than the direct group (χ²=5.879, P=0.015). The detection rate of NTM in the ultrasound group was statistically higher than that in the direct group too (χ²=7.720, P=0.005), while no statistical difference was observed for detection rate of MTBC between the two groups (χ²=0.175,P=0.676). Conclusion: The ultrasonic dispersion method can better detect mycobacteria and especially for NTM while controlling the contamination, indicating that it has great application potential in the reprocessing of mycobacterial liquid culture contaminated specimens.