The incidence of false-positive cultures for Mycobacterium tuberculosis
The incidence of false-positive cultures for Mycobacterium tuberculosis
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DOI：
10.1164/ajrccm.155.1.9001331
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发表时间：
1997-01-01
影响因子：
24.7
通讯作者：
Cave, MD
中科院分区：
文献类型：
--
作者：
Burman, WJ;Stone, BL;Cave, MD
由于特定菌株标记的粘性，由于交叉污染导致的结核分枝杆菌假阳性培养的频率一直难以确定。使用IS 6110和pTBN 12序列对从市卫生部门实验室前瞻性收集的5年以上的分离株进行DNA指纹图谱分析。我们回顾了所有分离株的临床和实验室记录，这些分离株具有匹配的DNA指纹，并在42天内相互处理; 8个分离株被归类为可能或明确的假阳性，占培养阳性患者的4.0%（8/199）。来自其他三个分枝杆菌实验室的42株分离株的便利样本也进行了DNA指纹图谱分析，发现5株（12%）为明确或可能的假阳性。标本初始处理过程中的交叉污染是假阳性培养物的最常见来源。三种假阳性培养物的交叉污染来源是含有菌株H37 Ra的实验室能力调查标本。13名患者中有10人被误诊为结核病，7人接受了不必要的多种药物治疗。临床医生应该意识到M假阳性培养的可能性。结核病和分枝杆菌实验室需要仔细审查程序，以尽量减少这种情况的发生。DNA指纹分析为假阳性培养物的研究提供了一个有价值的工具。
The frequency of false-positive cultures for Mycobacterium tuberculosis due to cross-contamination has been difficult to determine because of the tack of specific strain markers. Isolates collected prospectively over 5 yr from a municipal health department laboratory underwent DNA fingerprinting using the IS6110 and pTBN12 sequences. We reviewed the clinical and laboratory records of all isolates that had matching DNA fingerprints and were processed within 42 d of each other; 8 isolates were classified as probable or definite false-positives, representing 4.0% (8/199) of the culture-positive patients. A convenience sample of 42 isolates from three other mycobacterial laboratories also underwent DNA fingerprinting, and five (12%) were found to be definite or probable false-positives. Cross-contamination during initial processing of specimens was the most com mon source of false-positive cultures. The source of cross-contamination for three false-positive cultures was a laboratory proficiency survey specimen containing strain H37Ra. Ten of the 13 patients were misdiagnosed as having tuberculosis, and seven received unnecessary multidrug treatment. Clinicians should be aware of the potential for false-positive cultures for M. tuberculosis, and mycobacteriology laboratories need to carefully review procedures to minimize this occurrence. DNA fingerprinting provides a valuable tool for the study of false-positive cultures.