Presence of Mycobacterium fortuitum in respiratory tracts usually indicates mere colonization or transient
infection, whereas true pulmonary
infection occurs in patients with gastroesophageal disease. However, little is known about the diagnostic indications for true M. fortuitum pulmonary
infection and the natural history of the disease.
CASE PRESENTATION: A 59-year-old man was referred to our hospital for treatment against M. fortuitum pulmonary
infection. Fifteen years before the referral, he underwent total
gastrectomy, after which he experienced
esophageal reflux symptoms. After the referral, the patient was closely monitored without antimicrobial
therapy because of mild symptoms and no pathological evidence of M. fortuitum pulmonary
infection. During the observation, chest imaging showed migratory infiltrates. Two years after the referral, his lung biopsy specimen revealed foamy macrophages and multinucleated giant cells, indicating
lipoid pneumonia. However, he was continually monitored without any treatment because there was no evidence of nontuberculous mycobacterial
infection. Four years after the referral, he developed refractory
pneumonia despite receiving adequate
antibiotic therapy. After confirmation of granulomatous lesions, multiple antimicrobial
therapy for M. fortuitum resulted in a remarkable improvement with no exacerbation for over 5 years. Random amplified polymorphic
DNA polymerase chain reaction analysis revealed identical M. fortuitum strains in seven isolates from six sputum and one intestinal fluid specimens obtained during the course of the disease.
CONCLUSIONS: We have described a patient with M. fortuitum pulmonary
infection who presented with migratory infiltrates. The pathological evidence and microbiological analysis suggested that M. fortuitum pulmonary
infection was associated with
lipoid pneumonia and chronic exposure to gastrointestinal fluid. Therefore, physicians should carefully monitor patients with M. fortuitum detected from lower respiratory tract specimens and consider antimicrobial
therapy for M. fortuitum
infection when the patient does not respond to adequate
antibiotic therapy against common
pneumonia pathogens.