Mold & Bacteria Consulting Laboratories (MBL) has certification in the analysis of Legionella bacteria by the prestigious Environmental Legionella Isolation Techniques Evaluation (ELITE) program of the US Centers for Diseases Control and Prevention (CDC). You can view our current Certificate of Proficiency for Legionella Testing.
MBL is one of the only 3 Canadian independent laboratories having this industry-leading certification. MBL is also accredited by the Canadian Association For Laboratory Accreditation (CALA) for analysis of fungi and bacteria including Legionella.
Legionella Colonies
Legionella is a type of bacteria that is found primarily in warm or hot water environments (35- 37°C). These bacteria can cause Legionellosis. Legionellosis comes in two forms, Pontiac fever, the lesser of the forms, and also Legionnaires’ disease which is a more severe illness with a deadly type of pneumonia. Thousands of people get Legionnaires’ Disease in the United States each year.
The Centers for Disease Control and Prevention (CDC) reports between 8,000 and 18,000 cases of Legionnaires’ disease annually, but it also estimates that more than 90 percent of cases go unreported. Of the approximated 2.4 million cases of pneumonia that are diagnosed in hospital patients each year in the United States.
About 18,000 cases are confirmed as Legionnaires’ Disease and up to 600,000 cases of Legionnaires’ Disease are misdiagnosed as pneumonia because the hospitals do not perform the tests for Legionella.
Legionella bacteria were first identified as cause of pneumonia in 1976, after an outbreak of pneumonia among attendants of an American Legion convention in Philadelphia, Pennsylvania . Following the outbreak further investigation into Legionella was conducted and it was discovered that earlier unexplained pneumonia outbreaks could have been caused by these bacteria. The earliest cases of Legionnaires’ disease were shown to have occurred in 1965.
Legionella is acquired exclusively through inhalation of contaminated water droplets. The number of bacteria cells required to induce infection is not known, but varies according to age, general health, and other predisposing factors. However, the organisms must be present in sufficiently high concentration and must be suspended in aerosols between 3 and 5 microns in diameter.
Though it is possible that healthy people can be infected, people with compromised immune systems, respiratory illnesses, and cancer are much more likely to become sick. It is estimated that 10 to 20 percent of those infected die, but in individuals with compromised immune systems, the fatality rate is likely to be much higher.
Legionella identification is traditionally performed by growing the bacteria in special nutrient media (buffered charcoal yeast extract (BCYE) agar) that encourage the growth of Legionella and discourage the growth of other bacteria. This test is considered the “gold standard” for diagnosing an infection caused by Legionella bacteria. A positive culture may be determined in about 48 to 72 hours. Negative cultures are held for at least 14 days before a final result is reported.
Use of Biocides in Controlling Legionella
Legionella and other bacteria thrive in biofilm, which is impervious to most biocides. From time to time, pieces of biofilm break off and make their way out of the system through a faucet or showerhead. The microscopic, pathogen-rich particles aerosolize and can be inhaled. It is estimated that 70 percent of hospital water systems are likely colonized by Legionella bacteria. The immune-compromised are most susceptible to Legionnaires’ and other diseases caused by waterborne pathogens. Legionnaires’ disease has a reported mortality rate of up to 30%.
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