The association between computed tomography scan findings of pulmonary infection caused by atypical mycobacteria and bacillus count in sputum samples

Background: The use of imaging techniques is important for prompt diagnosis and treatment of atypical mycobacterial infections; it also reduces the burden of these infections. The purpose of the present study was to determine the association between computed tomography (CT) scan findings of pulmonary infection caused by atypical mycobacteria and bacillus count in sputum samples. Methods: This cross-sectional, observational, comparative study included 50 consecutive patients with pulmonary infection caused by atypical mycobacteria, who were hospitalized in Masih-Daneshvari Hospital of Tehran, Iran during 2012–2017. The association between CT scan findings of pulmonary infection caused by atypical mycobacteria and bacillus count in sputum samples was determined in these patients. Results: The results demonstrated that the presence of nodules smaller than 5 mm in diameter, consolidation, bronchiectasis, and pleural thickening were related to bacillus count in sputum samples (P < 0.05). Conclusion: Some CT scan findings, such as nodule diameter smaller than 5 mm, consolidation, bronchiectasis, and pleural thickening, may be indicators of atypical mycobacterial infection. Increased number of involved lobes with bronchiectasis can promote early diagnosis in patients with higher smear and culture grading.