GTS Legionella Water Testing Lab

GTS has been testing for Legionella spp. in water samples from cooling towers and potable water world-wide since 1981 when the Centers for Disease Control and Prevention began sending customers who wanted Legionella testing to us.

Our CDC quantitative test method was developed during research collaboration with CDC in 1979 and was published in Water Research 1985.

GTS test reports provide quantitative numbers of Legionella including 14 serogroups of Legionella pneumophila and 15 other Legionella species associated with human disease (L. anisa, L. bozemanii sg 1 & 2, L. dumoffi, L. feeleii sg 1 & 2, L. gormanii, L. hackeliae sg 1 & 2, L. jordanis, L. longbeachae sg ! & 2, L. maceachernii, L. micdadei, L. oakridgensis, L. parisiensis, L. sainthelensi, L. santicrucis, and L. wadsworthii).

Highest sample counts since January 1, 2008
Cooling Tower = 120,000 per ml
Water System = 10,350 per ml

For more information about testing for Legionella, go to Legionella 2003: An Update and Statement by the Association of Water Technologies (AWT)

Question: How do our test results compare to culture results?
Answer: Our test method produces quantitative results with environmental samples that are 10-fold to 100-fold more sensitive than culture. We use a modification of the original CDC test method; direct fluorescent monoclonal antibody (DFA) epifluorescence microscopy. Our test result of no Legionella observed (<10/ml) is equivalent to a culture result of <0.1/ml to <1.0/ml, assuming that the culture procedure is properly performed and validated by the DFA monoclonal antibody test.

Question: Why do we use the direct fluorescent antibody (DFA) method?
Answer: Because we can identify non-culturable Legionella that can cause outbreaks. Non-culturable, viable Legionella have been reported in several peer-reviewed journals, for example, Acta Pathologica, Microbiologica et Immunologica Scandinavica 113:45-53, 2005. Only DFA tests performed by trained laboratory personnel can identify these Legionella. Direct fluorescent antibody (DFA) tests using a battery of monoclonal antibodies have proven to be more sensitive and reliable with environmental water samples.

Because of legal liability for us and our customers, we do not use the 2005 CDC Procedures for the Recovery of Legionella from the Environment or the Association Francaise de Normalisation (AFNOR) or the ISO 11731-2:2004 culture membrane method or the UK Health and Safety Executive Legionella Guidelines or the OSHA Technical Manual, Section III, Chapter 7, Legionnaires’ Disease Appendix III 7.2 Physical Survey and Water Sampling protocols. Read more >>

GTS Legionella Laboratory
gilpin@legionella.com
Cellphone (410) 961-6638
D-U-N-S Number: 61-641-7551
Employer Identification Number: 52-1520322