Early diagnosis and favorable outcomes of pulmonary Mycobacterium avium complex disease diagnosed by gastric aspirate culture.

BACKGROUND

Diagnosing pulmonary Mycobacterium avium complex (MAC) disease in asymptomatic patients is challenging due to difficulty in collecting sputum culture. This study evaluated the clinical and characteristics and outcomes of patients diagnosed through gastric aspirate culture to assess its usefulness.

METHODS

We retrospectively analyzed 125 patients with radiological findings consistent with pulmonary MAC disease who had positive MAC cultures from gastric aspirate between April 2014 and March 2022. The "provisional diagnostic criteria" included one positive sputum culture with anti-GPL-core IgA antibodies or one positive sputum and gastric aspirate culture. The "tentative diagnostic criteria" included one positive gastric aspirate culture with anti-GPL-core IgA antibodies or two positive gastric aspirate cultures.

RESULTS

Among 125 patients, 103 were female, with a mean age of 65.0 years and an average BMI of 19.3 kg/m2. The primary reason for hospital visits was abnormal chest shadows in 68 cases (54.4 %). Of 106 cases where gastric aspirate was collected for diagnosis, 85 met the tentative diagnostic criteria, and 63 met the provisional criteria. Ultimately, 40 cases met the current diagnostic criteria. However, the average delay from tentative criteria to conventional diagnosis was 1078 days, and 605 days from provisional criteria. Macrolide-based therapy was initiated in 62 cases (58.5 %), achieving culture conversion in 51 cases (82.3 %), and 100 % in the tentative diagnosis group.

CONCLUSION

Many cases were not diagnosed via conventional criteria, leading to missed opportunities for early treatment. Utilizing gastric aspirate for diagnosis significantly reduced diagnostic delays, facilitating earlier treatment initiation and leading to favorable outcomes.