Routine sampling of water supplies and genomic sequencing of Legionella bacteria could play a key role in identifying the source of Legionnaires' disease outbreaks, according to a study. Image According to a genomic study of the Legionella bacterium that causes the disease, the measures could also serve public health to limit the spread of the infection. Better testing is critical, researchers say, because the disease - a severe form of pneumonia - is transmitted by inhaling the bacteria in aerosols - tiny droplets - from contaminated water. A team from the Universities of Edinburgh and Glasgow, Public Health Scotland and the Scottish Legionella Reference Laboratory compared the whole genome, or genetic code, of more than 3,000 Legionella samples found in patients and in water sources from Scotland and around the world. Legionella transmission in Scotland The results provided a new level of detail and new insights into the characteristics of Legionella bacteria and their transmission in Scotland. In analysing the genetic code, the researchers found that Legionella infections following travel were often closely related to other variants from the same UK or international destination. The analysis found that nearly one-third of community-acquired infections in Scotland - not related to hospitals or travel - were caused by a single variant. The team believes this variant should be closely monitored. In some hospitals, different variants of the bacterium were found over a long period of time - up to 17 years in some cases - suggesting that the bacteria persisted or were repeatedly introduced into hospital water systems.The team also noted that no cases of Legionnaires' disease have been reported in any Scottish hospital in the past 10 years. This is likely due to the effectiveness of new control measures introduced during that time, experts said. Our study indicates that regular sampling of water systems and genome sequencing of Legionella could be used to identify the source of new pathogenic variants before they become a clinical problem. Prof. Ross Fitzgerald Roslin Institute The findings have been published in The Lancet Microbe. This work has been funded by the Chief Scientist Office, UKRI and Wellcome. Related Links Epidemiological analysis of Legionnaires' disease in Scotland: a genomic study Fitzgerald lab Edinburgh Infectious Diseases Roslin Institute This article was published on 2022-11-03
