The number of Legionella infections has dramatically increased in Belgium over the past few years, according to a new study by researchers at UZ Brussels.
Legionella infections are caused by the Legionella bacteria. The most serious and deadly form is Legionnaire’s disease, a severe form of pneumonia.
Legionnaires’ disease does not spread from person to person, but is contracted through inhaling droplets of infected air.
Legionella is a type of bacteria naturally present in fresh water and soil. When it grows in stagnant warm water, it can become dangerous for humans.
The bacteria is often found in water pipes and installations like showers and air conditioners. Disease outbreaks typically occur in large buildings like hotels and hospitals.
Antibiotic-resistant variant found in Belgium
A recently released UZ study showed that the number of Legionella infections in Belgium doubled over the 10-year period between 2011 and 2022.
Every year, between 300 and 400 Belgians contract a Legionella infection.
There is a milder form called Pontiac fever, which resembles a mild flu, which many people reportedly contract without knowing it is a Legionella infection. In more serious cases, the infection develops into Legionnaires' disease.
The study showed that an antibiotic-resistant variant has been identified for the first time Belgium.
Dr. Charlotte Michel, clinical biologist and lead author of the study said: “This discovery shows that Legionella continues to evolve at the genetic level, including in ways that directly impact the effectiveness of our treatments.
“It is essential that we include antibiotic resistance monitoring as standard part of Legionella diagnosis going forward.”
The resistant strain showed similarities with previously discovered antibiotic-resistant strains in France, indicating a possible wider spread within Europe.
However, the Belgian patient reportedly had no travel history, meaning it was probably spread locally.
Legionnaires’ disease can be treated with antibiotics. Disease symptoms usually develop two to 14 days after infection. Symptoms include cough, fever, headaches, muscle aches and shortness of breath. No vaccine is available.
Legionnaires’ disease is named after the outbreak where it was first identified at a 1976 convention of the American Legion in Philadelphia.
