Imaging appearance of mycobacterium simiae pulmonary infection

Abstract

Aim: The purpose of this study was to identify the radiographic and CT scan findings in patients with Mycobacterium simiae pulmonary infections. Methods : A total of 40 patients with positive cultures for M. simiae were identified between January 2000 and August 2015. In our radiographic analysis, we included those with cultures that grew M. simiae as the only isolate. The patients chest X-rays and Computed Tomography scans were reviewed and Receiver Operating Characteristic (ROC) and inter- and intra-reader variability was recorded. Results : A total of 54 images were retrieved, 30 Chest X-rays and 24 CT scans. Out of the 9 patients who had chest X-rays, 3 (33.3%) patients had their x-rays read as normal while the rest 6 (66.6%) had abnormal findings. All patients had abnormal findings on their CT images. The most common radiographic findings were consolidations, bronchiectasis, nodules, ground glass opacities, and enlarged mediastinal lymph nodes. ROC scores demonstrated significant detection of nontuberculous mycobacteria (NTM) (p < 0.003) (95%; CI [0.589-0.864] and CI [0.566-0.844]) (p < 0.001) with good interobserver agreement (k=0.63). Conclusion : M. simiae infection has various radiographic presentations. It is imperative that radiologists recognize its common radiographic features. Furthermore, M. simiae must be considered even in immunocompetent patients. © 2018 Lebanese Order of Physicians.All right reserved.