Microbiological safety of bottled mineral water in patients susceptible to infections.

We evaluated the microbiological safety of bottled mineral water products commercially available in Japan. Of 10 bottled mineral water products manufactured in Japan, no bacteria or fungi were detected in 9 (90%), but 1 (10%) contained 1.8×103 colony-forming units (cfu)/mL. Of 12 bottled mineral water products manufactured in the EU, 11 (91.7%) contained 23–3.5×104 cfu/mL. On the other hand, of 5 bottled mineral water products manufactured in North America, 2 (40%) contained 2.3×102–2.5×103 cfu/mL. The detected microorganisms were glucose-nonfermentative Gram-negative bacilli such as Brevundimonas vesicularis, Moraxella spp., and Burkholderia cepacia, but Pseudomonas aeruginosa was not detected in any product. For immunocompromised host patients being managed in ultra-clean rooms, the examined bottled mineral water products manufactured in Japan, except 1, were microbiologically safe.