RESUMEN
Legionella spp. is transmitted from water to humans by aerosol-generating devices, including cooling towers [CTs]. There have not been published reports about Legionella in these systems in Qatar. Ten CTs in Qatar University were sampled on a monthly basis. Bacteria were recovered from 90 water samples by filtration and concentration. Legionella DNA copy number [CN] was assessed by quantitative RT-PCR. Legionella DNA was detected in 100% of the samples. The bacterial counts ranged from 0.006 to 199.56 CFU/mL, and critical counts were found in 51 [56.7 %] samples. Moreover, 7 [7.8%] samples showed a count of more than 100 CFU/mL. The highest counts were found in the months of May and June. These results suggest that this organism is found in high number in tested CTs, presenting a potential health risk to the local population