Identification of Mycobacterium shimoidei by molecular techniques: case report and summary of the literature

A 53-year-old woman from Melbourne, Australia, with squamous cell carcinoma of the oesophagus was shown by computed tomography (CT) scan to have a lef t apical cavity and inflammatory changes in the right lung consistent with aspiration. Acid-fast bacilli isolated from bronchial washings were identif ied biochemically first as Mycobacterium terrae, but later as M. shimoidei on the basis of 1) restriction fragment analysis and 2) sequencing of polym erase chain reaction (PCR) amplified 16S rDNA. Nine other descriptions of p atients with il I. shimoidei isolates were collated. The salient feature of isolates considered to be pathogenic was pulmonary cavitation. Most patien ts had underlying lung disease, including past tuberculosis or malignancy. Six of eight patients died of progressive respiratory illness, although the contribution of M. shimoidei was not always clear, and two patients improv ed. One patient with the acquired immune-deficiency syndrome (AIDS) died wi th Salmonella enteritidis and M. shimoidei isolated from blood cultures. On e isolate was regarded as a coloniser. There are insufficient clinical or s ensitivity data on which to base recommendations for therapy, but a combina tion of ethambutol, rifabutin and pyrazinamide could be considered.