Balcells M E, Huilcamán M, Peña C, Castillo C, Carvajal C, Scioscia N, García P
Infectious Diseases Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile.
Infectious Diseases Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Hospital Dr Gustavo Fricke, Viña del Mar, Chile.
Int J Tuberc Lung Dis. 2016 Jun;20(6):848-52. doi: 10.5588/ijtld.15.0872.
The nasopharynx is a known gateway for some mycobacterial species such as Mycobacterium bovis and M. leprae. M. tuberculosis can cross lymphoepithelial barriers in vitro, but its ability to colonise the nasopharyngeal mucosa in vivo has not been established.
To determine if M. tuberculosis can be transiently detected in nasopharyngeal mucosa of tuberculosis (TB) contacts as a preliminary step in the development of tuberculous infection.
Exploratory study conducted among asymptomatic household contacts of pulmonary TB cases. A chest X-ray, QuantiFERON(®) TB-Gold or tuberculin skin test and a bilateral nasopharyngeal swab for Xpert(®) MTB/RIF and mycobacterial culture were performed at baseline and repeated 8-12 weeks later.
Eighty-nine contacts were enrolled a median of 9 days after the diagnosis of the index case. At baseline, 29.9% were positive for latent tuberculous infection and one subject (1.1%) had a positive Xpert in the nasopharyngeal swab with a normal chest X-ray, negative QuantiFERON and negative induced sputum. After 12 weeks' follow-up, this subject developed a new cough and upper lobe infiltrates and M. tuberculosis grew in sputum. No other cases of active TB were detected at follow-up.
The detection of M. tuberculosis DNA in the nasopharyngeal mucosa of contacts is an infrequent event that in this instance preceded the development of pulmonary TB. Its pathogenic role requires further investigation.
鼻咽是一些分枝杆菌物种（如牛分枝杆菌和麻风分枝杆菌）已知的入侵通道。结核分枝杆菌在体外可穿过淋巴上皮屏障，但其在体内定殖于鼻咽黏膜的能力尚未得到证实。
确定在结核病（TB）接触者的鼻咽黏膜中是否能短暂检测到结核分枝杆菌，作为结核感染发展的初步步骤。
对肺结核病例的无症状家庭接触者进行探索性研究。在基线时进行胸部X线检查、结核菌素释放试验（QuantiFERON®）TB - Gold或结核菌素皮肤试验以及双侧鼻咽拭子检测Xpert® MTB/RIF和分枝杆菌培养，并在8 - 12周后重复检测。
在索引病例诊断后中位9天，89名接触者入组。基线时，29.9%的人潜伏结核感染呈阳性，一名受试者（1.1%）鼻咽拭子Xpert检测呈阳性，胸部X线正常，结核菌素释放试验阴性，诱导痰检测阴性。随访12周后，该受试者出现新的咳嗽和上叶浸润，痰中培养出结核分枝杆菌。随访期间未检测到其他活动性肺结核病例。
在接触者的鼻咽黏膜中检测到结核分枝杆菌DNA的情况很少见，在本病例中其先于肺结核的发生。其致病作用需要进一步研究。
