Co‐infection with Nocardia spp. in a patient with Mycobacterium avium complex pulmonary disease: A case report

Mycobacterium avium complex pulmonary disease (MAC‐PD) is sometimes accompanied by co‐infection with other pathogenic microorganisms such as Pseudomonas aeruginosa and Haemophilus influenzae. However, co‐infection with Nocardia spp. has been rarely reported. We report on a patient diagnosed as having co‐infection with Nocardia after treatment for MAC‐PD, which was successfully treated using trimethoprim‐sulfamethoxazole (TMP‐SMX). A 74‐year‐old woman with MAC‐PD was admitted to our hospital to undergo re‐examination for pathogenic microorganisms because chest computed tomography (CT) findings did not improve after treatment for MAC‐PD. She underwent bronchoscopy and Nocardia spp. was detected from bronchoalveolar lavage fluid culture. Chest CT findings improved after 6 months of treatment using TMP‐SMX. Co‐infection with other pathogenic microorganisms should be considered when chest CT findings worsen after adequate treatment of MAC‐PD. Chest CT findings of Nocardia pulmonary disease in immunocompetent patients can mimic those of MAC‐PD and should therefore be differentiated one from the other. We report on a case of Mycobacterium avium complex pulmonary disease (MAC‐PD) with Nocardia spp. co‐infection after treatment for MAC, where chest computed tomography (CT) findings showed improvement after treatment with trimethoprim‐sulfamethoxazole (TMP‐SMX).