Legionella testing

Cleaning and disinfection documents, disinfection protocols, independent Legionella test results, conforming certificates. 

Legionella testing Positive result below 1 x 102 inspect and retest. Positive result above 1 x 102 cleaning/disinfection program is necessary. 

Testing for Legionella requires special sampling techniques and usually requires a period of 14 working days from receipt of the sample to obtain a result. A positive result will include an identification of the Legionella species, and typically also of the serotypes 1 to 6, plus a determination of the number of the bacterium per milliliter of the original sample. 

NOTE In the United States at this time, there appear to be no federal or state regulations specifically concerning the level of Legionella sp. permissible or acceptable in cooling water. Positive test results do not predict the future safety of the cooling water system tested, only a total count at the time of sampling. This is not necessarily the position in other countries. 

Ruckdeschel G, Dalhoff A. The in-vitro activity of moxifloxacin against Legionella species and the effects of medium on susceptibility test results./. Antimicrob. Chemother., 1999, 43 (Suppl. B), 25-29. 

The L AL test is considerably more sensitive than the pyrogen test. As mentioned above, although the Legionella endotoxin is not very pyrogenic to rabbits it is easily detected by the LAL test. It has been estimated that there is a 1000-fold difference in sensitivity between the two tests but the LAL test only... 

The ability of the AcB/BcA strains to detect and accurately map a monogenic trait was initially tested in the identification of a locus controlling differential susceptibility to Legionella pneumophila (Fortin et al 2001b). It has been established that A/J macrophages are permissive to the invasion and replication by L. pneumophila while B6 macrophages can efficiently control their replication. This difference is determined by the expression of a single locus on chromosome 13... 

BDD electrodes are applied in a typical closed, pressurized electrolyzer (DiaCell ), and its technology has been successfully tested for Legionella inactivation in several water compositions and under various working conditions. 

Several current densities were applied to the DiaCell with an active electrode surface of 65 cm. The hydraulic flow was set at 160 L h l, and the water temperature was maintained between 22 and 26°C. Legionella solution (5 mL) was injected into each water sample without any treatment, and into samples of electrolyzed water. No test was performed passing Legionella through the DiaCell electrolyzer. 

Before each test of inactivation, Legionella was injected into the tap water sample, whose quality is shown in Table 23.2, and it was confirmed that the Legionella viability remained stable in tap water after a 1-hour test, as shown in Fig. 23.7, which shows the Legionella viability in hypochlorite solution as well. The minimal injection of hypochlorite into tap water in order to guarantee immediate inactivation requires a chlorine concentration range between 0.67 and 1.12 ppm. The total oxidant concentration was measured with the DPD standard method (value DPD 3) and expressed as total chlorine (ppm) even when the electrolytes contained no chloride. 

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