Antibiotic resistant E. coli has been found in multiple drinking water supplies in France. The resistance counters the critically important cephalosporin antibiotics. The findings highlight the presence of expanding reservoirs of these resistance genes, including reservoirs in the environment. The research is published August 22 in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.
“Drinking water is a well-recognized source of direct human contamination with waterborne pathogens, but the risk of human transfer of resistance genes has rarely been documented,” the investigators write. They note just several studies of resistance gene-contaminated water in developing nations “with poor water supply systems and/or sanitation facilities, coupled with limited controls of antibiotic usage and residues.” But their study is likely the first report from a high income country that documents production of this resistance gene, by E. coli, in drinking water supplies.
In the study, the investigators sampled 28 water supply systems throughout France. They collected one liter water samples from the locations where drinking water enters the distribution system. The water supplies sampled were chosen on the basis of having had water quality failures—detection of coliform bacteria which serve as indicators of fecal contamination—during the previous three years. (Coliform bacteria include E. coli and Enterococci.)
“All potential reservoirs—human, animal, and environmental—are now contaminated by extended spectrum beta-lactamases (the gene in question, acronym ESBL),” said Marisa Haenni, PhD, Senior Scientist, Agency for Food, Environmental, and Occupational Health & Safety (ANSES), Lyon, France. “Though this contamination strongly varies, depending on the studied reservoir and country, no one is protected from the sporadic presence of ESBLs in places that should be free of this resistant bacterium.”
Nonetheless, “water supplies in France are constantly improving as new potential threats are taken into account,” Haenni asserted, advising that people in developed nations need not drink bottled water.
ESBLs are generally found on plasmids, small pieces of DNA that can easily jump from one species of bacterium to another, spreading the resistance.
Cephalosporins are used in hospitals for serious and life-threatening diseases, and against such food born pathogens as salmonella and shigella, and more generally, for infections of the respiratory tract, the urinary tract, the kidneys, the bones, the ears, and the skin.