Legionnaires' disease caused by Legionella longbeachae: Clinical features and outcomes of 107 cases from an endemic area

Abstract

Background and objective: Legionella longbeachae is a predominant cause of Legionnaires' disease in some parts of the world, particularly in Australasia. Clinical reports of L. longbeachae infection are limited to case reports or small case series, and culture-confirmed cases. Methods: We reviewed the clinical characteristics and outcomes of L. longbeachae pneumonia in a large case series from Christchurch, New Zealand during a 4-year period when both PCR and cultures were used as routine diagnostic tools for Legionnaires' disease. Cases of Legionella pneumophila pneumonia were reviewed for comparison. Results: A total of 107 cases of L. longbeachae infection were identified by PCR and/or culture. The median age was 65 years (range 25-90 years), 63% were male, and most became unwell during spring or summer. Presenting clinical features were similar to those reported for community-acquired pneumonia, with headache, myalgia and diarrhoea being common. Elevated C-reactive protein, hyponatraemia and abnormal liver function tests were also common. History of productive cough, involvement of both lungs, and high bacterial load were independently associated with culture of Legionella from lower respiratory samples. One quarter required intensive care unit admission, and 5% died. Among patients given antimicrobial therapy before admission, those given agents without anti-Legionella activity were more likely to be admitted to the intensive care unit. Limited comparisons were made with the 19 L. pneumophila cases over the same time period. Conclusion: Characteristics of L. longbeachae pneumonia are broadly similar to those reported for communityacquired pneumonia from a variety of other populations, except for the spring/summer seasonality.

Year in review 2016: Respiratory infections, acute respiratory distress syndrome, pleural diseases, lung cancer and interventional pulmonology

“…Legionnaires disease is a relatively common cause of CAP, accounting for 1–10% of patients outside of epidemics . While Legionella pneumophila is most frequently encountered worldwide, Isenman et al . provided a timely reminder that Legionella longbeachae is the predominant cause in some regions including parts of Australasia .…”

Ten questions concerning the aerosolization and transmission of Legionella in the built environment

“…17 There is also an increase in incidence of cases caused by one species, L. longbeachae , in the spring in certain regions. 51 While warmer weather has been shown to be associated with increased presence of Legionella in natural water systems, 52 legionellosis incidence does not appear to follow climate zone trends in the United States. 23 This is likely due to capability for engineered water systems to provide ideal conditions for the growth of Legionella year-round.…”

Risk Factors forLegionella longbeachaeLegionnaires’ Disease, New Zealand

“…New Zealand has the highest reported incidence of Legionnaires’ disease in the world ( 1 ), and in part because of the more rigorous testing in this country, the epidemiology of detected Legionnaires’ disease in New Zealand differs from that of most other countries; a high proportion of cases are caused by L. longbeachae ( 3 – 5 ). L. longbeachae can be found in soil and compost-derived products ( 6 – 9 ).…”