Mycobacterium xenopi pulmonary infections: a multicentric retrospective study of 136 cases in north-east France

Owing to its low incidence, the management of Mycobacterium xenopi pulmonary infections is not clearly defined. A multicentre retrospective study was performed to describe the features of the disease and to evaluate its prognosis.

All patients with M xenopi satisfying the 1997 ATS/IDSA criteria from 13 hospitals in north-east France (1983-2003) were included in the study. Clinical, radiological and bacteriological characteristics and data on the management and outcome were collected.

136 patients were included in the analysis, only 12 of whom presented with no co-morbidity. Three types of the disease were identified: (1) a classical cavitary form in patients with pre-existing pulmonary disease (n = 39, 31%); (2) a solitary nodular form in immunocompetent patients (n = 41, 33%) and (3) an acute infiltrate form in immunosuppressed patients (n = 45, 36%). 56 patients did not receive any treatment; the other 80 patients received first-line treatment containing rifamycin (87.5%), ethambutol (75%), isoniazid (66.2%), clarithromycin (30%) or fluoroquinolones (21%). After a follow-up of 36 months, 80 patients (69.1%) had died; the median survival was 16 months (range 10-22). Two independent prognostic factors were found: the acute infiltrate form was associated with a bad prognosis (hazard ratio 2.6, p = 0.001) and rifamycin-containing regimens provided protection (hazard ratio 0.325, p = 0.006). Clarithromycin-containing regimens did not improve the prognosis.

In contrast to recent guidelines, this study showed three different types of the disease (cavitary, nodular or diffuse infiltrate forms) with a different prognosis. In order to improve survival, all patients with M xenopi infection should be treated with a rifamycin-containing regimen. The usefulness of clarithromycin remains to be evaluated.