Computed Tomographic Features Associated with Pulmonary Melioidosis versus Pulmonary Tuberculosis in Diabetic Patients: A Retrospective Comparative Cohort Study

Pulmonary melioidosis is frequently mistaken for pulmonary tuberculosis because of overlapping clinical and radiological features, often delaying appropriate treatment. We conducted a retrospective comparative cohort study at a tertiary care center in southern India between January 2018 and August 2025 to compare chest computed tomography (CT) features of microbiologically confirmed melioidosis and tuberculosis in diabetic adults who underwent CT within 30 days of symptom onset. A total of 151 patients were included: 46 with melioidosis and 105 with tuberculosis. Cavitation (n = 81/105 [77.1%] versus n = 20/46 [43.5%], P <0.001) and hydropneumothorax (n = 11/105 [10.5%] versus n = 0/46 [0%], P = 0.019) were more common in tuberculosis. In contrast, when compared with tuberculosis, melioidosis was associated with more frequent bilateral lung involvement (n = 37/105 [35.2%] versus n = 26/46 [56.5%], P = 0.015), pleural effusion (n = 28/105 [26.7%] versus n = 23/46 [50.0%], P = 0.005), and hilar lymphadenopathy (n = 6/105 [5.7%] versus n = 8/46 [17.4%], P = 0.032). Despite these differences, there was substantial overlap in CT findings, with upper-lobe predominance, centrilobular nodules, and mediastinal lymphadenopathy seen in both groups. In multivariable analysis, cavitation was associated with significantly lower odds of melioidosis than tuberculosis (adjusted odds ratio: 0.25, 95% CI: 0.12-0.54, P <0.001). Pulmonary melioidosis and pulmonary tuberculosis, therefore, show substantial overlap on chest CT in diabetic patients, and imaging should be interpreted as an adjunct to targeted microbiological diagnosis rather than a substitute for it.