HARRISBURG, Pa. -- A research team headed by Penn State Harrisburg Assistant Professor of Environmental Microbiology Katherine Baker has found the cause of chronic gastritis, peptic ulcer disease and certain types of stomach cancer -- Helicobacter pylori (H. pylori) bacterium -- in river, creek and lake water in Central Pennsylvania.
The study represents the first report of live H. pylori in surface water in the United States, demonstrating a major reservoir for this organism outside the human body.
Although H. Pylori infects half the world's population, surface water as a primary source of infection has been unknown prior to the research project involving Dr. Baker and John Hegarty, a Penn State Harrisburg graduate student in Environmental Pollution Control and a graduate of Bishop McDevitt High School in Harrisburg.
H. pylori was first described in the early 1980s by Australian researchers. The organism is found in the stomachs of the majority of people in the world. In most people, it does not cause any disease. In a small percentage of individuals, the organism causes serious consequences. It is now accepted that H. pylori is the cause of most duodenal ulcers and between 70 and 80 percent of gastric ulcers. In the late 1980s, a link between H. pylori and certain types of stomach cancer was shown by researchers at Stanford University.
Normal testing procedures do not identify the presence of live H. pylori in water. Therefore, the Penn State Harrisburg researchers had to develop a method to detect the organism. They combined two staining techniques to enable them to count live H. pylori. The bacterium was found in more than 75 percent of the 36 tested surface water samples.
Baker and Hegarty delivered the results of their research last month at the 98th General Meeting of the American Society of Microbiology in Atlanta.
"Water looks to be a major factor in the transmission of the bacterium," Baker says, pointing out that the organism was found in both surface water and untreated well water from shallow wells where surface water contamination is likely to occur.
Epidemiological studies have shown that infection with H. pylori is associated with levels of sanitation, particularly water sanitation. In developed countries, less than 50 percent of the population is typically infected, while in developing countries, the infection is almost universal. In addition, the bacterium's DNA has been found in sewage-contaminated water samples in Peru where the infection rate is extremely high, leading researchers to speculate that water might be a source of infection. Initially, Baker limited her study to surface water. But upon learning a fellow employee's mother had just been diagnosed with an H. pylori infection, the study expanded.
"Her drinking water came from an untreated shallow well and she had just recently started to drink lots of water to help her lose weight," Baker explains.
Water examined from the well after a rain storm, when surface water contamination was likely, showed the presence of live H. pylori. The Penn State Harrisburg faculty member notes that "while we do not have conclusive evidence that the contaminated well water caused the woman's H. pylori infection, the possibility certainly exists."
Baker emphasizes that the research to date has been limited to untreated water sources. "More than half of Pennsylvania's residents obtain their drinking water from shallow wells which receive no disinfection. Therefore, we targeted non-municipal water supplies in our research," she says.
Since the detection method is quite labor intensive, the team's next step is to develop a quick and easy test for monitoring water for this harmful bacteria.
There is no evidence that H. pylori is found in municipal or treated water supplies and research by the EPA indicates that chlorine disinfection kills the bacterium. "I certainly have no qualms about drinking municipal water," Baker adds.
For those people who obtain their drinking water from untreated wells, Dr. Baker recommends having the well tested to see if surface water contamination occurs. If it does, or if individuals, wish to take additional precautions, having a disinfection system installed is a good idea.