70 swab specimens from shower heads and bath water and 30 specimens from water tanks as a total of 100 water specimens from 20 different units of the Istanbul Faculty of Medicine were collected and investigated for Legionella spp. The specimens were concentrated via filtration and decontamination procedures were applied to the filtrates.

In the cultures of the three swab specimens from shower heads and bath water yielded four different Legionella isolates (L.jordanis, L.feeleii, L.micdadei, and Legionella spp.) and two specimens from water tanks yielded two different Legionella isolates (L.jordanis and Legionella spp.), making up a total of six Legionella isolates as a whole. Through latex agglutination and examination of phenotypic characteristics, four of the six isolates were identified to the species level. Colonization rate with Legionella spp. were determined as 5% and isolation rate as 6%.

Three of the six isolates were obtained from shower of some specific units like Oncology and Bone Marrow Transplantation Units in which immunosuppressed patients a re hospitalized. The remaining three were isolated from the shower head in the Department of Pediatrics Section of Cardiology and the water tanks in the intensive care unit and the operation room of the Emergency Unit,.

The time for a positive culture was longer with direct inoculation (8 days on BCYE, 6.3 days on selective media) when compared to inoculation after decontamination (4.3 days on BCYE and 5.2 days on selective media). The pH values of culture positive specimens were found to vary between 6.24 and 7.14. Pseudomonas spp. were determined as the most frequent contaminant bacteria in water specimens.

The sensitivity of direct inoculation versus inoculation after decontamination was 85%. All of the six isolates grew on BCYE agar when inoculated after decontamination. The sensitivity for isolation of Legionella spp. from specimens on MWY selective medium was found as 71% and as higher than those on other media. These results led us to conclude that it is adequate for water specimens to be inoculated both onto BCYE and MWY media, after decontamination, to isolate Legionella spp..