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A recent study explains potential new method for decontaminating Legionella bacteria and similar hardy environmental pathogens. A game changer for chronic offending sources of Legionnaires’ disease. But this method will also likely work on other, similar pathogens.
The hardy Legionella bacteria have the ability to survive for years in a contaminated water system. Water towers in large hotels like those in Las Vegas and high rises in New York have been vehicles for many Legionnaires’ disease outbreaks. But other water systems can breed these harmful microbes too.
For example, at least 12 people died during the Flint water crisis in Michigan between 2014 and 2015. And just last month there was a Legionnaires’ disease outbreak at an assisted living community in Vermont.
Researchers from Cornell University in New York recently publish a paper in the Journal of Bacteria explaining how Legionella and Coxiella burnetiid (the germ responsible for Q fever) live in the body and in the environment.
These scientists discovered a key enzyme that could be a potential target for treatment and decontamination.
These bacteria behave differently in host environment as opposed to an environmental environment.
“We already knew that when these bacteria come out into the environment, they differentiate into intrinsically resistant forms in order to survive,” said Dipak Kathayat, senior author and postdoctoral researcher in the College of Veterinary Medicine.
In the host, the cells can be more mobile. But in the environment, the bacteria must be more hardy to survive.
“In our study, we look at what is different between the forms of the cells … and what we found is that the bacteria remodels its envelope, it changes its outer coat,” said Kathayat.
When Legionella bacterial cells enter the water (or in the case of Coxiella burnetiid and soil), the cell envelope strengthens. This makes Coxiella bacteria more resistant to antibiotic treatments and reduces the effects of decontaminating Legionella bacteria.
As the bacteria settle in, those cell envelopes begin to modify, making them difficult (or even impossible) to treat.
Kathayat and his team discovered a key enzyme used by both microorganisms to change from the rapidly replicating infectious forms to the hardy environmental form that resists decontamination efforts.
This enzyme is called LD-transpeptidase.
This discovery opens the door for treatment options that can exploit that vulnerable transition.
“We could decontaminate with different chemical agents by targeting the LD-transpeptidase,” said Kathayat. “ We also suggest that the chemical agents or drugs that target these enzymes could be utilized for treating chronic infection, too. It can lead to a better, rational therapeutic approach.”
A class of antibiotics called carbapenems that is designed to target this enzyme is already available. While further studies are necessary to verify this treatment option for chronic infection of Legionnaires’ disease and Q fever, the team performed initial laboratory analysis to see if it would work.
Preliminary results produced great results.
“I could see the results of the antibiotic susceptibility results with the naked eye, I could see that the form that’s resistant to antibiotics becomes susceptible to carbapenems,” said Kathayat. “That excites me the most.”
In addition to the potential use for treatment and decontaminating Legionella, researchers also suggested that copper (a metal that also inactivates LD-transpeptidase) could also be used to decontaminate reservoirs.
Legionnaires’ disease is the infection caused by Legionella bacteria. A naturally occurring microorganism in freshwater environments. Places like lakes and streams. The risk of exposure in these environments, however, is rather small.
The real problem comes when the bacteria grow and spread in human-made water systems.
Cooling towers used for centralized air-cooling systems for buildings or other industrial processes are the most common modern mode of Legionella infection. Though there are other water sources of exposure.
Large, complex plumbing systems or those with dead pipes where construction is in progress allow bacteria to grow and spread. Hot water tanks and hot water heaters provide a happy, warm environment and a place to hang out, leading to potential Legionella bacterial growth. Shower heads and sink faucets as well as hot tubs provide modes of exposure. Even decorative fountains and water features that can be found in both indoor and outdoor locations.
Legionnaires’ disease is not generally spread from person to person. This method of infection occurs in extremely rare and specific circumstances.
People become infected with Legionella bacteria by breathing in contaminated water droplets caused by aerosolized water in the air.
In some cases, people can become sick by aspirating contaminated drinking water. This happens when water accidentally gets breathed into the lungs while drinking. A common description of this is “water going down the wrong hole.” Those with increased risk of aspiration or with swallowing difficulties may experience this type of exposure risk more than others.
Most healthy individuals do not fall ill after being exposed to Legionella bacteria. However, certain groups of people are at an increased risk. While the infection can be treated with antibiotics, it is a serious illness. Most will require hospitalization to make a full recovery. Legionnaires’ disease can be fata. 1 in 10 will die from the infection. This jumps to 1 in 4 if illness is acquired while staying in a healthcare facility.
Common risk factors include:
Legionnaires’ disease is often under-diagnosed, as it is similar to other types of pneumonia. In fact, chest x-rays often cannot differentiate between Legionnaires’ disease and pneumonia. This is why recovery often takes longer than needed – appropriate medication specifically for Legionella bacteria is not administered when not properly diagnosed.
Symptoms of Legionnaires’ disease often include cough, shortness of breath, fever, muscle aches, and headaches. In some cases, symptoms of diarrhea, nausea, and confusion may be present. Symptoms usually begin between 2 and 14 days after exposure but could be longer.
If you’d like to know more about food safety topics in the news, like “Researchers Discover New Method for Decontaminating Legionella Bacteria and Similar Hardy Environmental Pathogens,” check out the Make Food Safe Blog. We regularly update trending topics, foodborne infections in the news, recalls, and more! Stay tuned for quality information to help keep your family safe, while The Lange Law Firm, PLLC strives to Make Food Safe!
By: Heather Van Tassell (contributing writer, non-lawyer)
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