[Comparison of tests results between T-SPOT.TB and QuantiFERON-TB Gold In-Tube in a contact investigation].

BACKGROUND: We compared T-SPOT.TB (T-SPOT) and QuantiFERON-TB Gold In-Tube (QFT-GIT) test results in a contact investigation. SUBJECTS AND METHODS: The index case was a male lecturer at a vocational school in Tokyo. Chest X-ray examinations and T-SPOT tests were performed on all 397 contacts, and QFT-GIT was performed on a subset of these contact subjects. RESULTS: Chest X-ray examination showed no evidence of tuberculosis in any subjects. Among 389 contacts that underwent T-SPOT testing, 5 showed a positive reaction, 3 showed borderline reactions (1 positive borderline and 2 negative borderline), and 381 were negative. Among 56 contacts tested using both QFT-GIT and T-SPOT, 4 were positive, 1 was borderline, and 51 were negative by QFT-GIT. By T-SPOT, 2 contacts were positive, 1 was borderline positive, and 53 were negative. Preventive chemotherapy was indicated for the 5 positive and 1 borderline positive contacts identified by the T-SPOT test. DISCUSSION: Chest X-ray examination and the T-SPOT test did not identify the TB outbreak. CONCLUSION: The majority of contact subjects were negative by both tests, suggesting that both have a high specificity in contact investigations. However, the moderate concordance rate indicates that further testing is necessary to fully evaluate these tests.

Multidrug-Resistant Tuberculosis Outbreak among Immigrants in Tokyo, Japan, 2019-2021.

In mid-September 2019, a teenage Chinese male student and part-time waiter in Tokyo was diagnosed with multidrug-resistant (MDR) sputum smear-positive pulmonary tuberculosis (TB). This study describes the outbreak investigation of his friends and colleagues at the restaurant. We investigated 6 friends and 15 colleagues; 5 friends and 13 colleagues underwent interferon-γ release assay (IGRA). Of these, 3 friends (60.0%) and 4 colleagues (30.8%) were IGRA-positive. Each of the friends and colleagues was found to have MDR-TB (20% and 7.7%, respectively). Challenges during the investigation were the unavailability of regimens for latent TB infection (LTBI) for contacts with MDR-TB, budgetary constraints concerning implementing computed tomography (CT) scans for the contacts, frequent address changes of foreign-born patients and contacts, investigation during the coronavirus disease pandemic, and variations of alphabetical expression of the names of the patients and contacts, particularly for those from China. It is recommended that the national government officially adopt prophylaxis regimens for LTBI with MDR-TB, address the budgetary constraints regarding CT scans, and deploy liaison officers for coordinating investigations involving many foreign-born patients and contacts scattered in multiple municipalities. The names of foreign-born persons could more accurately be identified using both the alphabet and Chinese characters.