Bhattacharya M, Dietrich S, Mosher L, Siddiqui F, Reisberg B E, Paul W S, Warren J R
Veterans Affairs Lakeside Medical Center, and Department of Medicine, Northwestern University Medical School, Chicago, Illinois, USA.
Am J Clin Pathol. 1998 Mar;109(3):324-30. doi: 10.1093/ajcp/109.3.324.
At the Veterans Affairs Lakeside Medical Center, two episodes of specimen cross-contamination with Mycobacterium tuberculosis were detected during a 54-month period by molecular strain typing using DNA restriction fragment length polymorphism for 3 patients without clinical or radiologic signs of tuberculosis (TB). A cross-contaminated specimen was the only culture-positive specimen for each of the 3 patients. Laboratory features of cross-contamination included acid-fast smear negativity, growth only in broth or solid medium, and growth in solid medium with 5 or fewer colonies. Retrospective analysis demonstrated identical features for occasional culture-positive specimens from 54 patients with TB during the same period. However, productive cough, pleural pain, weight loss, night sweats, chest radiograph results suggestive of TB, positive tuberculin skin testing, and/or multiple culture-positive specimens were invariably present in patients with TB with such specimens. Most patients with TB (50/54; 93%) had multiple specimens positive in culture for M. tuberculosis, and the few patients with TB with single culture-positive specimens were symptomatic. These results indicate that correlation with clinical manifestations is necessary to determine the significance of isolated, acid-fast smear negative, and/or low-yield culture-positive specimens. Although the prevalence of specimen cross-contamination is low (0.1%), possible sources (especially the use of single-reagent delivery systems for multiple specimens) should be eliminated by mycobacteriology laboratories.
在退伍军人事务部湖滨医疗中心，在54个月的时间里，通过使用DNA限制性片段长度多态性进行分子菌株分型，检测到3例无结核病临床或放射学征象的患者出现了两起结核分枝杆菌标本交叉污染事件。对于这3例患者，每份交叉污染的标本都是唯一培养阳性的标本。交叉污染的实验室特征包括抗酸涂片阴性、仅在肉汤或固体培养基中生长以及在固体培养基中生长且菌落数为5个或更少。回顾性分析显示，同期54例结核病患者偶尔培养阳性的标本具有相同特征。然而，结核病患者出现此类标本时，总是伴有咳痰、胸痛、体重减轻、盗汗、胸部X线片结果提示结核病、结核菌素皮肤试验阳性和/或多个培养阳性标本。大多数结核病患者（50/54；93%）有多个结核分枝杆菌培养阳性的标本，少数仅有单个培养阳性标本的结核病患者有症状。这些结果表明，要确定分离出的、抗酸涂片阴性和/或低产量培养阳性标本的意义，必须与临床表现相关联。尽管标本交叉污染的发生率较低（0.1%），但分枝杆菌实验室应消除可能的污染源（特别是对多个标本使用单试剂输送系统）。
