Legionella Identification
Our Legionella Detection Program (an inclusive system approach) is performed using conventional culture method with multiple selective media, DFA confirmations, and latex agglutination to identify isolates as Legionella pneumophila or other Legionella species with a high accuracy.
SanAir has developed a comprehensive web-based reporting format indicating, in an easy to read graphical format, the number of colony forming units for Legionella at a site specific water system. (Examples: cooling towers, potable water systems, fountains, a/c systems, respiratory equipment, shower heads, ice makers, whirlpool bath treatment equipment, humidifiers, dialysis equipment, carpet cleaning equipment etc.
Environmental Legionella Isolation Techniques Evaluation (ELITE) Program is the only official Legionella testing certification program in U.S. The ELITE Program was created by Centers for Disease Control and Prevention (CDC) as a way for laboratories to test their Legionella isolation techniques proficiency against standardized samples. SanAir Technologies Laboratory was accredited by the CDC ELITE program on 4/29/09 as an ELITE program member.
Health Impacts
Legionella, the precursor bacterium to Legionnaires’ disease, is a serious public health issue in the United States. According to the National Institutes of Health (NIH), Legionella bacteria can be found living in organic material attached to inner pipe surfaces in aging water infrastructure environments such as cooling towers, plumbing systems, and water features. While many people exposed to Legionella may not experience severe symptoms, the disease can lead to a dangerous form of pneumonia, especially in vulnerable groups such as older adults, smokers, or those with weakened immune systems.
Culture
SanAir uses a two-step process for the identification of Legionella species from water sources. The first step is conventional culture using BCYE and BCYE selective media. These media are selective for Legionella species while it simultaneously suppresses the growth of other contaminating organisms. Conventional culture: Potable water will be filtered to concentrate the sample. Direct and acid-treated filtered potable water samples will be pated to 2 types of media: BCYE, BCYE selective media. Direct and acid-treated cooling tower samples will be plated to 3 types of media including BCYE and other two BCYE selective media. Examination and Interpretation: All culture plates will be incubated at 37 °C and will be examined at 4-7 days. Isolate identification will be confirmed by direct fluorescent antibody stain (DFA) in the second step.
DFA Confirmation
The direct fluorescent antibody (DFA) test is currently used at SanAir Technologies Laboratory to identify Legionella pneumophila and other Legionella species. It is a rapid microscopic procedure in which antibodies specific for Legionella pneumophila and other Legionella species are tagged with a fluorescent dye. A presumptive Legionella isolate by culture from an environmental source will be placed on a slide and exposed to a panel of DFA reagents. A positive reaction under the fluorescent microscope confirms the identification. DFA is sensitive and highly specific when used for Legionella species confirmation.
Legionella pneumophila Serotyping
Latex agglutination will be used to confirm isolates as Legionella pneumophila serogroup1 and 2-14 and other Legionella species. The results will be reported as positive including Legionella species, concentration as CFU/ml and serogroup if available, and negative as no Legionella detected.
Analytical Services
Culture
SanAir uses a two-step process for the identification of Legionella species from water sources. The first step is conventional culture using BCYE and BCYE selective media. These media are selective for Legionella species while it simultaneously suppresses the growth of other contaminating organisms. Conventional culture: Potable water will be filtered to concentrate the sample. Direct and acid-treated filtered potable water samples will be pated to 2 types of media: BCYE, BCYE selective media. Direct and acid-treated cooling tower samples will be plated to 3 types of media including BCYE and other two BCYE selective media. Examination and Interpretation: All culture plates will be incubated at 37 °C and will be examined at 4-7 days. Isolate identification will be confirmed by direct fluorescent antibody stain (DFA) in the second step.
DFA Confirmation
The direct fluorescent antibody (DFA) test is currently used at SanAir Technologies Laboratory to identify Legionella pneumophila and other Legionella species. It is a rapid microscopic procedure in which antibodies specific for Legionella pneumophila and other Legionella species are tagged with a fluorescent dye. A presumptive Legionella isolate by culture from an environmental source will be placed on a slide and exposed to a panel of DFA reagents. A positive reaction under the fluorescent microscope confirms the identification. DFA is sensitive and highly specific when used for Legionella species confirmation.
Legionella pneumophila Serotyping
Latex agglutination will be used to confirm isolates as Legionella pneumophila serogroup1 and 2-14 and other Legionella species. The results will be reported as positive including Legionella species, concentration as CFU/ml and serogroup if available, and negative as no Legionella detected.