Molecular Detection of Mycobacterium tuberculosis in Oral Mucosa from Patients with Presumptive Tuberculosis
WP3: Development of new diagnostic methods
Barbara Molina-Moya, Nelly Ciobanu, Marta Hernandez, Cristina Prat-Aymerich, Valeriu Crudu, Emily R. Adams, Alexandru Codreanu, Derek J. Sloan, Luis E. Cuevas and Jose Dominguez
J. Clin. Med. 2020, 9, 4124; doi:10.3390/jcm9124124
Tuberculosis (TB) diagnosis is increasingly based on the detection of Mycobacterium tuberculosis complex (MTBC) DNA in sputum using molecular diagnostic tests as the ﬁrst test for diagnosis. However, sputum can be diﬃcult to obtain in children, patients without productive cough, and the elderly and approaches testing non-sputum samples are needed. We evaluated whether TB can be detected from the oral mucosa of patients with TB. Adults with presumptive TB were examined using culture, Xpert MTB/RIF, smear microscopy and X-Rays. Oral mucosa swabs collected on PrimeStore-MTM, stored at room temperature if tested within 30 days or at−20◦C if examined at a later time. RT-PCR was performed to detect M. tuberculosis DNA. Eighty patients had bacteriologically-conﬁrmed TB, 34 had bacteriologically-negative TB (negative tests but abnormal X-rays) and 152 were considered not to have TB (not TB). Oral swabs RT-PCR were positive in 29/80 (36.3%) bacteriologically-conﬁrmed, 9/34 (26.5%) bacteriologically-negative and 29/152 (19.1%) not TB. The yield varied among samples stored for less and more than 30 days (p = 0.013) from 61% (11/18) and 29% (18/62) among bacteriologically conﬁrmed, and 30.8% (4/13) and 23.8% (5/21) among bacteriologically-negative participants. Among not TB patients, the speciﬁcity was 80.9% (123/152), being 78.3% (18/23) among samples stored less than 30 days and 81.4% (105/129) among samples stored for more than 30 days (p = 0.46). The detection of M. tuberculosis in oral mucosa samples is feasible, but storage conditions may aﬀect the yield.