Bacteria may lurk in water pipe film
By Garry Palmateer, M.Sc., GAP EnviroMicrobial Services Inc.
Researchers at Robert Gordon University in Aberdeen, say that a bacterium, Helicobactor pylori, has been implicated in a variety of gastrointestinal diseases. Half of the people older than 50 years of age in developed countries carry the bacterium in their guts, with an even larger proportion of people affected in Third World countries, say the scientists in a paper published by the London-based New Scientist magazine.
Several animals may harbour the micro-organism, but so far no one has found a reservoir in the environment. Donald Reid and his Scottish colleagues suspected that Helicobactor pylori might thrive in biofilms. These form when micro-organisms colonize surfaces such as the insides of water pipes, often surrounding themselves with a sticky protective film. "Biofilms occur naturally in all water distribution systems," Reid says.
Helicobactor pylori is a bacterium found to play a major role in the cause of chronic gastric inflammation and, in some cases, stomach cancer. Chronic gastritis, which some people have endured for years, has been completely eliminated and the gastric mucous has returned to a pristine state with the eradication of H. pylori in the system (Blaser, 1992).
Helicobactor pylori is a gram-negative, curved or spiral bacterium that lives in the semipermeable mucous layer of the stomach. It has an unusual survival mechanism that allows it to live in a very acidic environment. H. pylori has the ability to biodegrade urea and produce ammonia abundantly, which, in turn, raises the pH in the immediate vicinity of the bacteria.
The prevalence of these bacteria in human infections in developed countries, such as Canada and the USA, is 0.5 to 1.0 percent per year in children, and approximately 50 percent in 60 year old adults. However, in developing countries, most persons are infected by H. pylori by the age of ten.
Poor sanitary practices, including non-potable water, may be part of the cause of the high frequency of occurrence in Third World countries.
Shahamat, et al., 1993, demonstrated the survival of H. pylori in water as culturable up to 48 hours and, in some cases, for 20 to 30 days. Using tritium-labelled substrates, they showed H. pylori to survive in water, but the bacterium was not reproducible using standard culturing techniques. However, they were definitely viable.
Dr. Rita Colwell has shown that similar bacteria, once ingested, could resuscitate and produce infection in human volunteers. To my knowledge, I do not believe that this feeding of human volunteers has been conducted with H. pylori.
West, et al., 1992, has also demonstrated the survival of H. pylori in water under varying physical and chemical conditions. They concluded that H. pylori could survive in water for prolonged periods under a range of physical variables. The results indicate that survival of H. pylori in environmental (natural) water may act as a potential reservoir of infection.
In 1991, Klein, et al., provided evidence of a water source as a risk factor for H. pylori in infection in Peruvian children.
Based on my own knowledge of the survival of pathogens in biofilm, I would agree with Dr. Reid that H. pylori is highly likely to survive in the matrix of a nutrient-rich biofilm.
REFERENCES
Blaser, J.M. 1992. Helicobactor pylori: its role in disease. Clin. Infect. Dis. 15: 386-393.
Klein, P., Graham, D., Gaillorer, A., Opekum, A., and Smith, E. 1991. Water source as risk factor for Helicobactor pylori infection in Peruvian children. The Lancet. 337: 1503-1506.
Shahamat, M., Mai, U., Paszko-Kolva, C., Kessel, M., and Colwell, R. 1993. Use of autoradiography to assess viability of Helicobactor pylori in water. J. Appl. Environ. Microbial. 59: 1231-1235.
West, A., Millan, M., and Tompkins, E. 1992. Effect of physical environment on survival of Helicobactor pylori. J. Clin: Pathol. 45: 228-231.