Tsukamurella and mycobacterium tuberculosis pneumonia co-infection

ABSTRACT

Case Report Tsukamurella species are aerobic, partially acid fast saprophytes commonly isolated from soil and water. They are opportunistic pathogens known to infect multiple organs and can contribute to significant pathologies such as bacteremia, peritonitis, and respiratory tract infections. Moreover, Tsukamurella shares certain characteristic properties to Mycobacterium tuberculosis and Actinomyces species, including the acid fast stain, which can contribute to misdiagnosis of patients. A 68 year old female patient presented to the ED for shortness of breath, fatigue, and weight loss for 6 months. The patient's past medical history includes pulmonary fibrosis, type 2 diabetes, coronary artery disease with stent, hyperlipidemia, hypertension, and M. tuberculosis infection when she was 3 years old in Finland. On admission, labs revealed thrombocytosis (reactive 555 000/microL), leukocytosis (14 450/microL), and microcytic anemia (9.4 microg/dl). Moreover, C reactive protein was elevated and procalcitonin was normal (0.06 microg/l);a COVID-19 PCR was negative. An X-ray revealed severe patchy and interstitial infiltrates throughout both lungs with parenchymal scarring and pleural thickening in the periphery of the left mid-lung zone with multifocal pneumonia. Blood and sputum cultures were performed under the impression of pneumonia, and treatment with azithromycin and ceftriaxone was started. A M. tuberculosis infection was suspected due to a positive AFS. Further chest CT suggested multifocal pneumonia within the left lung in addition to apparent cavitary lesions versus bulla, a chronic interstitial lung disease with traction bronchiectasis, calcified right lower lung nodule, and calcified hilar lymph nodes suggesting a history of granulomatosis diseases. A bronchoscopy with Bronchoalveolar lavage was performed. The initial sputum specimen direct smear showed acid-fast stain positive with Actinomyces growth, and Penicillin G was added to the treatment. Samples were sent to the state department lab, and biopsy revealed granulomatous inflammation negative for malignant cells. One month later, the patient's sputum culture showed Tsukamurella for High-performance liquid chromatography (HPLC). Moreover, a rifampicin sensible M. tuberculosis complex by NAA was also positive six weeks later. The patient was started on a complete TB regimen and continued in the outpatient pulmonology clinic with the addition of levofloxacin for three months and rifampicin substituted for rifabutin. As demonstrated in the case above, a Tsukamurella infection can present similarly to a Mycobacterium infection. Patients may be misdiagnosed or potentially be co-infected. Our patient was further tested and appropriately treated for Tsukamurella after further extensive diagnostic screenings. Due to a high rate of missed cases, it is important to keep Tsukamurella infection on the differential diagnosis as the patient presentation may initially appear to be a Mycobacterium or other pulmonary infection. Copyright © 2023 Southern Society for Clinical Investigation.