“Further analyses of two bronchoalveolar lavage samples by highly sensitive total DNA sequencing found readings compatible with Legionella spp.”.
On 3 September 2022, ANLIS reported that amplification products of the 16S ribosomal gene for Legionella spp. from the two samples of bronchoalveolar lavage sequenced by metagenomics and analyzed by four different bioinformatic methods, produced results compatible with Legionella pneumophila.
Confirmation of these results is expected upon completion of the sequencing processes. This laboratory result supports evidence compatible with Legionnaires’ disease. Blood culture and seroconversion tests continue to be conducted to complement the diagnosis of Legionella infection.
Legionnaires’ disease, the pneumonic form, has an incubation period of 2 to 10 days (but up to 16 days have been recorded in some outbreaks). It is an important cause of community- and hospital-acquired pneumonia; and although uncommon, Legionnaires may cause outbreaks of public health significance. Initially, symptoms are fever, mild cough, loss of appetite, headache, malaise and lethargy, with some patients also experiencing muscle pain, diarrhoea and confusion. The severity of Legionnaires’ disease ranges from a mild cough to rapidly fatal pneumonia. Untreated Legionnaires’ disease usually worsens during the first week.
Mortality from Legionnaires’ disease depends on the severity of the disease, the use of antibiotic treatment, the setting where Legionella was acquired, and whether the patient has underlying conditions, including immunosuppression. The death rate may be as high as 40–80% in untreated immunosuppressed patients and can be reduced to 5–30% through appropriate case management, depending on the severity of the clinical signs and symptoms. Overall, the death rate is usually between 5–10%.
