Detection and Quantification of Legionella pneumophila from Water Systems in Kuwait Residential Facilities

The prevalence of Legionella pneumophilia in water systems of residential facilities in Kuwait was performed during the period from November 2007 to November 2011. A total of 204 water samples collected from faucets and showerheads in bathrooms (n = 82), taps in kitchens (n = 51), and water tanks (n = 71), from different locations of residential facilities in Kuwait were screened for Legionella pneumophila by the standard culture method and by real time polymerase chain reaction (RT-PCR). Out of the 204 samples, 89 (43.6%) samples were positive for Legionella spp., 48 (23.5%) samples were detected by the standard culture method, and 85 (41.7%) were detected by RT-PCR. Of the culture positive Legionella samples, counts ranged between 10 to 2250 CFU/L. Serological typing of 48 Legionella isolates revealed that 6 (12.5%) of these isolates belonged to Legionella pneumophila serogroup 1, 37 (77.1%) isolates to Legionella pneumophila serogroup 3, and 1 isolate each (2.1%) belonged to serogroups 4, 7, and 10. The minimum inhibitory concentration (MICs) of the 46 environmental L. pneumophila isolates against the 10 antimicrobials commonly used for Legionella infection treatments were determined. Rifampicin was found to be the most active against L. pneumophila serogroups isolates in vitro.