First case report of pulmonary and cutaneous nocardiosis caused by Nocardia mexicana in Iran

BackgroundNocardiaare aerobic partially acid-fast bacteria that are environmentally ubiquitous. This group of bacteria causes a rare bacterial infection of either the lungs (pulmonary) or body (systemic) that usually affects immunocompromised individuals.Nocardia mexicanawas first isolated in 2004 from a patient with chronic bronchitis. However, there have been few reports on the clinical significance of this organism up to now. We herein report the first cases ofN. mexicanain patients with pulmonary and cutaneous infection from Iran. Case presentation A 57-year-old man was admitted to hospital due to a cutaneous wound on his left foot, fever, weakness, persistent cough and chest pain. At first, due to clinical examination and laboratory test, the patient was diagnosed as having tuberculosis. However, PCR ofMycobacterium tuberculosiswas negative from broncho-alveolar lavage (BAL) samples. Direct PCR of BAL was performed for this patient and according to the clinical examinations and microbiological evaluations; the micro-organism was identified asN. mexicanaand was isolated from both BAL and the wound. Finally, the patient was treated with linezolid and amikacin. Conclusion The infections, with actinomycetes such asNocardia , are easily neglected or misdiagnosed due to the fastidious nature of the organism and the inadequate microbiological experience of laboratories in the hospitals of developing countries. This case shows that hospitals should consider a better laboratory protocol to deal with the clinical cases in which fastidious organisms, and in particularNocardia , are involved.