Scientists at the Technical University of Munich in Germany said they have developed a measuring chip that will identify the existence of Legionella within 34 minutes, according to recently published research in the journal “Biosensors and Bioelectronics.”
Legionella is the bacteria that causes Legionnaires’ disease, which can be identified with a urinalysis. Trying to determine the exact source of the illness, however, can be time-consuming – especially when time is of the essence.
The current method of testing for the existence of Legionella involves the collection of water samples. That, however, typically takes from 10 to 14 days to return a result.
The illness’ origin is confirmed when germs in the process water of a technical system exactly match those identified in the patient. Often, however, numerous systems must be tested. Finding the source of the illness quickly is imperative.
The problem with such delayed reporting is that the existence of Legionella – rod-shaped bacteria that multiply in warm water and can cause life-threatening pneumonia or respiratory infection – can reach an infectious level in as short as one week. If a disease outbreak has already occurred, identifying the actual source as soon as possible becomes critical for preventing additional exposures.
Chip gets name: “LegioTyper”
The measuring chip, which was given the name “LegioTyper,” is an inexpensive, one-time use device that contains a microarray of 20 different antibodies. Each of the antibodies binds to a different subtype of Legionella pneumophila, which is responsible for 80 percent of all infections and is considered the most dangerous of the almost 50 Legionella species.
If any of the Legionella subtypes are present in the water sample, the chip will detect its presence within 34 minutes (chemicals such as luminol and hydrogen peroxide are used to make the subtype appear by causing a chemiluminescence reaction).
The LegioTyper project, which was funded by the German Federal Ministry of Education and Research, will be introduced to the public for the first time at the Analytica 2018 trade fair in Munich next week.
Climate change to blame?
Legionnaires’ disease outbreaks have made headlines across the United States nearly annually since the disease was discovered in 1976. That was the year more than 200 attendees at an American Legion Convention in Philadelphia were sickened, and 34 of them died.
Legionnaires’ disease – a severe type of pneumonia or lung infection – is “an emerging disease in the sense that the number of recorded cases of Legionnaires’ in the United States continues to increase,” said Laura Cooley, MD, MPH from the Respiratory Diseases Branch of the Centers for Disease Control and Prevention (CDC).
Cooley said the increase is due to a rise in the susceptibility of the population, with more and more people on immunosuppressive medications. In addition, there could be more Legionella in the environment, with warmer temperatures creating the right conditions for bacterial growth.
The last three years have been the hottest years on record, with NASA ranking 2016 as the warmest and 2017 second-warmest.
Legionnaires’ facts and figures
The CDC estimates that 25,000 cases of Legionnaires’ disease occur in the United States on a yearly basis. Only 5,000 cases, however, are reported, because of the disease’s non-specific signs and symptoms.
Legionella bacteria are contracted by inhaling microscopic water droplets (generally, mist or vapor). The bacteria, which thrive in warm water, are found primarily in human-made environments. Water sources that provide optimal conditions for the growth of the infectious bacteria, according to the Occupational Safety and Health Administration (OSHA), include:
- cooling towers, evaporative condensers, and fluid coolers that use evaporation to reject heat; these include many industrial processes that use water to remove excess heat
- domestic hot-water systems with water heaters that operate below 60°C (140°F) and deliver water to taps below 50°C (122°F)
- humidifiers and decorative fountains that create a water spray and use water at temperatures favorable to growth
- spas and whirlpools, such as those in hotel pool areas
- dental water lines, which are frequently maintained at temperatures above 20°C (68°F) and sometimes as warm as 37°C (98.6°F) for patient comfort
- other sources including stagnant water in fire sprinkler systems and warm water for eyewashes and safety showers.
Who is most at risk of infection?
Anyone can get the disease, but those at the greatest risk of infection include:
- people 50 years old or older
- smokers (current or former)
- heavy drinkers of alcoholic beverages
- people with chronic lung disease
- people with weakened immune systems
- organ-transplant recipients (kidney, heart, etc.)
- individuals following certain drug protocols (for instance, corticosteroids).