PR 544 - Antibacterial properties of copper may reduce E.coli
0157 bacteria in copper water pipes
A recent study by Dr. James Walker at the
Centre for Applied Microbiology & Research (CAMR) determined that three independent
factors (water temperature, water hardness and pipe material) affect the survivability of E.
coli O157 in potable water systems. Regarding pipework material selection copper has a
significant antibacterial advantage over both polybutylene and stainless steel.
Copper demonstrated an antibacterial advantage over polybutylene for every temperature range and water hardness condition studied. In all water conditions copper demonstrated either stronger or equivalent antibacterial properties compared to stainless steel.
Dr W Keevil (CAMR) said: "Our experiments indicate that when used with cool soft drinking water resources, copper water piping systems have the potential to reduce the risk of human infection from E. coli O157 bacteria." The concentration of toxic E. coli O157 was 100 times lower on copper substrates than on stainless steel and polybutylene.
The study also found that copper has strong anti-biofouling characteristics, i.e. inhibiting the deposition of bacteria, in cool soft waters. However, biofouling was very significant on both polybutylene and stainless steel. Keevil commented: "Biofilms are harbingers of E. coli O157 and other microbial pathogens and they pose a significant risk to human health." After seven days submersion in soft cool water little biofilm was detected on the copper substrates whilst nearly 80% of stainless steel and 90% of polybutylene substrates were covered with biofilms.
For moderately hard potable waters copper imparts very strong anti-biofouling advantages over polybutylene at 10oC, 20oC and 40oC. For hard potable waters piping materials play a lesser role in preventing biofouling.
Attached: About Escherichia coli (E. coli) O157
Editorial Enquiries:
Nicholas
Hay |
|
4th December 2000 |
PR544 |
About Escherichia coli (E. coli) O157
E. coli O157 is a highly infectious ACDP Hazard Group 3 foodborne and waterborne pathogen. This strain of bacteria produces potent verocytotoxins, which can cause haemolytic colitis, haemolytic uraemic syndrome (kidney disease), and even death.
E. coli O157 bacteria infect tens of thousands of people around the world every year. An outbreak in Japan caused 9,000 people to become sick. A 1997 outbreak in Scotland was responsible for 500 infections and 20 deaths. And in the U.S., over 500 people became ill and three children died after eating undercooked hamburgers infected with E. coli O157.
It is believed that just ten to fifty highly toxic E. coli O157 organisms are sufficient to infect humans with illness. The infections are difficult to treat and antibiotics may prompt the bacteria to release even more verocytotoxins. In healthy individuals, E. coli O157 infections usually last three to five days. However, the bacteria can victimise children under 14 years of age, the elderly, and immunocompromised individuals with serious complications.