Introduction: Concurrent infections or co-infections in patients diagnosed with Coronavirus Disease-19 (COVID-19) are not uncommon and predict a pejorative prognosis. A co-infection accounts for 1 out of every 5 cases of COVID-19 and increases the likelihood of adverse health outcomes such as mechanical ventilations, ICU admissions, and death. Specifically, Legionella spp. co-infection presents additional challenges in COVID-19 patients because of its rarity, similar clinical presentation to SARS-CoV-2, and poorer outcomes without prompt treatment. Cases Presentation: Case 1. A 62-year-old female presented with a 3-day history of subjective fever and worsening shortness of breath. Room air saturation (saO2) was 70% and improved to 100% on noninvasive positive- pressure ventilation (NIPPV). Lung auscultation revealed rales BL. Chest X –Ray (CXR) showed patchy airspace opacities bilaterally (BL), SARS-CoV-2 PCR and urine legionella antigen tests were positive. The diagnosis of hypoxic respiratory failure secondary to COVID-19 and Legionella pneumonia was made. Patient was admitted to intensive care unit (ICU) and managed with decadron, remdesivir, one unit of convalescent plasma for COVID-19 and Azithromycin for Legionella. Patient subsequently developed acute respiratory distress syndrome (ARDS). ARDS protocol was initiated. 13 days after, the patient was compassionately extubated. Case 2. A 41-year-old male presented with 5-day history of fever, worsening shortness of breath, cough and diarrhea. Patient admitted history of ethanol abuse. SaO2 was 88% and improved on oxygen canula. Lung auscultation revealed rhonchi BL. CXR showed extensive left lung consolidation. Urine test for legionella antigen was positive. COVID-19 PCR was negative, but SARS-CoV-2 IgG was reactive. The diagnosis of Legionnaire disease was made. Despite initial treatment with Azithromycin, patient's hypoxia continued to worsen requiring NIPPV, and subsequently mechanical ventilation in the ICU. The adjunction of empiric treatment for COVID-19 with convalescent plasma, remdesivir and steroids improved both clinicals and laboratory findings. Discussion: The cases illustrated the practical challenges of managing COVID-19 and legionella co- infection. Legionella spp and SARS-CoV-2 overlapping incubation periods and similar clinical presentations and complications. In the absence of diagnosis and treatment, legionella pneumonia has an intrinsic mortality rate of up to 80%. As some COVID-19 mitigation strategies, such as the closure of businesses, have enhanced the conditions for Legionella spp proliferation, the incidence of Co-infection with COVID-19 may increase. We recommend clinicians to have high-indexed suspicion of COVID-19 and Legionella co-infection in order to obtain complete work up at patient’s initial presentation.
