Sir,
The COVID-19 pandemic has caused a historic public health emergency, with an estimated 458 million confirmed cases and 6 million deaths.[1] The highly transmissible SARS-CoV-2 virus can cause severe pneumonia as well as extrapulmonary sequelae, making accurate diagnosis and management crucial.[2] Legionnaire’s disease is a severe atypical bacterial pneumonia that can be associated with SARS-CoV-2 infection.[3] Like SARS-CoV-2 infection, legionella may be associated with extrapulmonary symptoms, including diarrhea, hyponatremia, and neurological manifestations such as encephalopathy, among others.[4] Importantly, the mortality rate of legionella infection is high, with one study reporting over 6% mortality despite appropriate antibiotic therapy with either azithromycin or a fluoroquinolone.[5]
A 74-year-old male presented to our institution with dyspnea, cough, and fever, found to be hypoxic with laboratory abnormalities including hyponatremia, hypophosphatemia, transaminitis, and acute kidney injury. Infectious work up detected SARS-CoV-2 RNA and a positive legionella urinary antigen. Chest x-ray was obtained demonstrating diffuse bilateral infiltrates [Figure 1]. He was treated with a 7-day course of azithromycin and symptoms as well as laboratory abnormalities resolved.
Figure 1.
High resolution chest X-ray from our patient with Legionella pneumonia demonstrating diffuse bilateral infiltrates
While the COVID-19 pandemic continues to stress health-care systems worldwide, the presence of SARS-CoV-2 infection does not preclude the presence of other pneumonias. Multiple case reports have described SARS-CoV-2 and Legionella coinfection.[3,6,7] In 2 of 3 cases, a fever was documented. In addition, hyponatremia was seen in all three cases and an elevated white blood cell count and procalcitonin in 2 of 3 cases. These reports highlight the various overlapping signs and symptoms that make diagnosis challenging. The high mortality associated with both pneumonias necessitates a differential on the part of the healthcare provider to include bacterial superinfections in patients presenting with suspected or confirmed COVID-19 infection. Further, rapid diagnosis of bacterial pneumonia may allow for avoidance of COVID-19-specific therapy, such as dexamethasone or tocilizumab, which may affect viral clearance and alter recovery from bacterial pneumonia.
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REFERENCES
- 1.WHO Coronavirus (COVID-19) Dashboard. [Last accessed on 2022 Apr 27]. Available from: https://covid19.who.int/
- 2.Moghimi N, Di Napoli M, Biller J, Siegler JE, Shekhar R, McCullough LD, et al. The neurological manifestations of post-acute sequelae of SARS-CoV-2 infection. Curr Neurol Neurosci Rep. 2021;21:44. doi: 10.1007/s11910-021-01130-1. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3.Sanchez A, Elliott EI, Wang P, Spichler-Moffarah A. Legionella pneumophila and Staphylococcus aureus co-infections in a patient with SARS-CoV-2. BMJ Case Rep. 2022;15 doi: 10.1136/bcr-2021-248536. e248536. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Mondino S, Schmidt S, Rolando M, Escoll P, Gomez-Valero L, Buchrieser C. Legionnaires' disease: State of the art knowledge of pathogenesis mechanisms of legionella. Annu Rev Pathol. 2020;15:439–66. doi: 10.1146/annurev-pathmechdis-012419-032742. [DOI] [PubMed] [Google Scholar]
- 5.Herwaldt LA, Marra AR. Legionella: A reemerging pathogen. Curr Opin Infect Dis. 2018;31:325–33. doi: 10.1097/QCO.0000000000000468. [DOI] [PubMed] [Google Scholar]
- 6.Arashiro T, Nakamura S, Asami T, Mikuni H, Fujiwara E, Sakamoto S, et al. SARS-CoV-2 and legionella co-infection in a person returning from a Nile cruise. J Travel Med. 2020;27 doi: 10.1093/jtm/taaa053. taaa053. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Verhasselt HL, Buer J, Dedy J, Ziegler R, Steinmann J, Herbstreit F, et al. COVID-19 co-infection with Legionella pneumophila in 2 tertiary-care hospitals, Germany. Emerg Infect Dis. 2021;27:1535–7. doi: 10.3201/eid2705.203388. [DOI] [PMC free article] [PubMed] [Google Scholar]