Post-COVID acute pulmonary nocardiosis: Another novel post-COVID infection.

Abstract

Dear Editor, Treatment of COVID-19 remains challenging, especially in patients with severe disease. Immunosuppressive therapies such as steroids and cytokine blockers are beneficial to control the cytokine storm. However, these drugs increase the risk of opportunistic infections. Nocardiosis is caused by an actinomycete, which primarily affects immunocompromised patients. Here we report a patient with acute localized pulmonary nocardiosis, post severe COVID disease. A 70-year-old male patient with no addictions and comorbidities presented to the emergency room with complaints of high-grade fever, cough with copious brown sputum, left-sided pleuritic chest pain for 2 weeks, and breathlessness for 3 days. He had severe COVID-19 disease with respiratory failure 4 weeks ago for which he was treated with IV remdesivir and IV methylprednisolone 40 mg twice daily for 7 days and discharged. At presentation, he had a respiratory rate of 30 breaths/min and saturation of 60% on room air, which improved to 95% with 5 liters/minute of oxygen support. Arterial blood gases (ABG) showed type 1 respiratory failure. Chest X-ray showed a consolidation in the left lower zone. High-resolution computed tomography (HRCT) chest revealed consolidation in the left lower lobe with internal breakdown and minimal pleural effusion [Figure 1a]. Total leukocyte count and C-reactive protein (CRP) were elevated (21,700 cells/mm3 and 320 mg/L, respectively). Sputum showed gram-positive, acid-fast, branching filamentous structures, morphologically resembling Nocardia species [Figure 1b, c], and hence a diagnosis of acute pulmonary nocardiosis was made. The patient was treated with oral trimethoprim-sulfamethoxazole (TMP-SMX) and IV meropenem for 4 weeks. The patient improved with treatment and was off oxygen support after a week and hence discharged. On follow-up after 3 weeks, antibiotics were changed to oral linezolid and TMP-SMX for 5 months. After completion of therapy, the patient is asymptomatic and the HRCT chest showed near-complete resolution of the left lower lobe consolidation with residual fibrotic bands [Figure 1d].Figure 1: (a) Axial slice of a high-resolution computed tomography scan of the chest showing consolidation of the left lower lobe with internal breakdown. (b) Direct examination of sputum smear after modified acid-fast staining revealing branching filamentous acid-fast organisms (40 × magnification). (c) Positive culture of the same sputum specimen on the blood agar plate. (d) Axial slice of a high resolution computed tomography scan of chest post-treatment, showing near-complete resolution with residual fibroticNocardiosis, an opportunistic infection, has been reported rarely in post-COVID-19 patients. To the best of our knowledge, there are only three case reports to date.[1,2] Nocardia species are ubiquitous saprophytic gram-positive bacteria of the “aerobic actinomycetes” group.Click or tap here to enter text.[3] The primary route of transmission is inhalational, from environmental sources. The majority of patients with pulmonary nocardiosis are immunosuppressed or have chronic lung disease. Radiology usually demonstrates irregular nodular lesions that may have cavitation. “Halo sign,” diffuse consolidations, and pleural effusions have been reported. The definitive diagnosis of nocardiosis requires isolation of the organism. Nocardia appears as a filamentous bacterium with hyphae-like branching and a “beaded” acid-fast appearance on microscopy.[4] Sulfonamides are the treatment of choice for nocardiosis. TMP-SMX is the most widely used drug. Alternative treatment options include amikacin, imipenem, meropenem, ceftriaxone, cefotaxime, minocycline, moxifloxacin, levofloxacin, linezolid, tigecycline, and amoxicillin-clavulanic acid.[3] The duration of treatment is 6–12 months. Our patient, who was otherwise healthy and had received only a short course of corticosteroids developed pulmonary nocardiosis, which suggests that it is vital to investigate for uncommon etiologies in patients presenting with secondary infections post-COVID-19 disease. COVID-19 infection apart from the drugs used in its treatment as a cause of immune suppression needs further research. Abbreviations IV – Intravenous, ABG – Arterial blood gases, HRCT – High resolution computed tomography, CRP- C-reactive protein. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.