Bottled water is a highly regulated product that must meet certain standards established by state, national and international regulatory bodies before it may be distributed. Bottled water is therefore widely considered a safe beverage. However, even within safety guidelines, a variety of bacteria can still be detected in most commercial bottled water available in the United States.
A Study of Bottled Waters
In a study conducted by Texas Southern University, 35 different brands of bottled water were tested for biological contamination and other national and international guidelines for drinking water quality. The types of water tested included 16 types of spring water, 11 identified as purified and/or fortified tap water, five were carbonated water and three were distilled water. The study indicated that six spring waters and three brands of bottled tap water showed minor bacterial contamination. However, none of the carbonated or distilled waters were found to contain detectable levels of bacteria. The identified bacteria in the spring waters included five types of Gram-negative bacteria (i.e. Klebsiella terrigena, Ralstonia pickettii, Acidovorax temperans,and Acidovorax delafieldii and Agrobacterium rhizogenes) and two types of Gram-positives (i.e. Burkholderia glumae and Bacillus Thermoglucosidasius). The bottled tap waters showed only two types of Gram-negative bacteria, Burkholderia glumae and Moraxella caviae.
The Klebsiella genus of bacteria is among the eight most frequently reported as causing diseases in hospitals. The ability of Klebsiella terrigena to cause disease in humans in unknown, as it is only rarely isolated from humans, and is typically found in water due to its abundance in soil.
Ralstonia pickettii is not generally considered bacteria that cause disease in humans. However, hospitals have reported Ralstonia pickettii infections in critically ill patients with cystic fibrosis and Crohn's Disease. It is also typically found in lake and river water due to the abundance of it in soil.
Acidovorax Temperans and Acidovorax Delafieldii
Acidovorax bacteria are consistently present in the sludge water of water treatment plants. It is considered a normal component of activated sludge treatment systems. There has been only one reported case of Acidovorax-associated disease in humans.
Agrobacterium is typically reported due to the impact it has on plants. It is typically found in soil and considered harmless to humans. However, agrobacterium has been reported to infect humans with weakened immune systems.
Burkholderia glumae infections are an emerging bacterial pathogen to rice and other plants. It is typically found in soil but one case has been reported of a Burkholderia glumae lung infection in an 8-month old baby.
Bacillus Thermoglucosidasius is typically found in soil samples. It has not been reported as a human pathogen.
Is the Water Safe?
Bottled water are regulated and generally considered safe for human consumption. However, in critically ill patients or individuals with comprimised immune systems, some of the bacteria found in the spring or purified-tap bottled water have been reported to cause infections.