Concomitance of COVID-19 and legionnaires' disease - a case series

Coronavirus disease-2019 (COVID-19) and legionnaires disease (LD) caused by Gram-negative water-born bacteria Legionella pneumophila show certain similarities, including a predisposition to pulmonary involvement and extrapulmonary manifestations in some of the patients infected. One disease can mimic the other, both can rarely coexist.

The authors describe 7 such cases (5 females), aged 51-90 years (mean 69.7 years) detected while screening 133 subjects with moderate to severe pneumonia and confirmed COVID- 19, which constituted 5.3% of the patients in whom urinary antigen test (UAT) for L. pneumophila was performed. The patients had multiple concomitant disorders: hypertension (6), heart failure (4), diabetes (4), obesity (4), coronary heart disease (3), chronic kidney disease (3), chronic obstructive pulmonary disease (3), anemia (3). Positive UAT was obtained at admission in 4 patients, and on 3rd, 11th and 14th days of hospitalization in the remaining 3 patients. One patient also had positive UAT for Streptococcus pneumoniae. We analyzed: radiological imaging, laboratory data (CRP, interleukin-6, procalcitonin, troponin I, BNP), ECG, echocardiography, treatment and outcome. Three patients required a modification of initial antibiotic therapy, two developed Clostridioides difficile infection. The duration of hospitalization ranged from 13 to 59 days (mean 24.3 days); two patients died.

The authors suggest that the coexistence of COVID- 19 and LD may result in prolonged hospitalization, in increased mortality risk and in subsequent cardiovascular complications, including takotsubo syndrome (TTS) which was found in 2 cases, both presented as focal TTS (fTTS).