When Coronavirus Disease 2019 (COVID-19) Pneumonia Isn't Enough: A Rare Case of Bacterial Coinfection

Introduction: Atypical bacterial coinfections, including more rare organisms such as Legionella pneumophila, can complicate coronavirus disease 2019 (COVID-19) infections. Care should be taken to avoid anchoring bias and ensure all bacterial coinfections are diagnosed and treated in patients with COVID-19. CASE REPORT: A 49-year-old male with no past medical history developed abdominal pain, diarrhea and cough on April 4, 2020. He tested positive for SARS-CoV 2 on April 6th given there were several people at his work that had recently contracted coronavirus disease 2019 (COVID-19). Over the next week he developed progressive fever, cough, anosmia, ageusia and then dyspnea with exertion which prompted him to seek medical care. Shortly after admission, he became more febrile, tachycardic and hypoxic requiring oxygen supplementation via high-flow nasal cannula. His oxygen requirements continued to worsen, and he was transferred to the ICU and intubated. His procalcitonin was elevated at 8.99 and he was started on empiric broad spectrum antibiotics. Tracheal aspirate was tested via PCR and returned positive for Legionella pneumophila. He also tested positive for Legionella urinary antigen. He received hydroxychloroquine for 7 days, IV doxycycline for 10 days, ceftriaxone for 6 days and piperacillin-tazobactam for 2 days. He gradually improved and was successfully weaned off supplemental oxygen. He was discharged after a 10-day hospital stay with minimal respiratory symptoms. DISCUSSION: Among patients diagnosed with COVID-19, Legionella bacterial coinfection appears to be rare. In a systematic review published in July 2020, Rawson et al reported that only 8% (62/806) of patients diagnosed with COVID-19 were diagnosed with a bacterial pneumonia coinfection and found only one patient who had COVID-19 and Legionella. However, it has been reported that there may be an increased risk of Legionella infections during the COVID-19 pandemic due to water systems being used less often because of lockdown orders. In September 2020, De Giglio et al reported that a large Italian hospital found a significant increase in Legionella pneumophila isolates on routine water system testing in two of three wards which had been closed for over a month due to emergency reorganization. It remains important to keep Legionella bacterial co-infection on the differential when treating COVID-19 since it may require a longer treatment regimen than what is recommended for treating standard community acquired pneumonia. In addition, the pandemic response has the potential to increase the risk of legionella infections secondary to stagnant water systems in lockdowns.