The most dangerous antibiotic-resistant strains of E. coli are transmitted not through food but through contact with human feces.

While it’s important to wash your hands carefully after handling raw chicken, it may be even more important to wash them after going to the bathroom. The most dangerous antibiotic-resistant strains of E. coli, called ESBLs, are transmitted not through food, according to new research, but through contact of human feces with human mouths.

British researchers examined many strains of ESBL-E. coli in human blood and feces, sewage, farm slurry, live animals, and raw meat, fruits and vegetables.

They found that one multidrug-resistant strain, ST131, responsible for a mortality rate as high as 35 percent in humans, was found in more than 60 percent of human bloodstream infections, but was extremely rare in live animals and nonexistent in foods.

The study, in Lancet Infectious Diseases, concludes that many of the E. coli strains that make people seriously ill come from other humans, not food or animals (though foods can also contain dangerous strains).

The senior author, David M. Livermore, a professor of microbiology at the University of East Anglia, explained that there are some strains of are E. coli that are harmless and just live in your gut. Others cause mild food poisoning. And finally there are the E. coli that are antibiotic resistant and often lead to serious illness and death.

“Good kitchen hygiene remains important,” he said, “but with these antibiotic-resistant E. coli, toilet hygiene becomes vitally important.” For many of the strains that are causing major disease, “food is not the source. It’s humans.”

But how best to protect yourself from E coli? Wash your hands properly. “When you wash your hands with soap, what the soap does is to detach the microbes from your hands, but the microbes remain alive,” says Prof Sally Bloomfield of the London School of Hygiene and Tropical Medicine. “The important part of washing your hands is rinsing them. That’s what takes the microbes off your hands.”

How to wash your hands properly

Use plenty of soap and be vigorous. “Rub them for at least 15 seconds, making sure that you rub them properly, from palm to palm, as well as rubbing the back of your hands. Interlace your fingers and rub them together. Rub around the backs of each of your fingers and thumbs,” Bloomfield says. “That’s the way to mechanically detach all of the organisms from your hands.”

After rinsing, dry your hands thoroughly to remove any microbes left lurking behind. (Be sure to change your hand towels regularly – every few days, or every day if you have children – on a hot wash of 60C or more to kill bacteria.)

If you’re not able to wash your hands using soap and running water, Bloomfield recommends using antibacterial hand gel to kill any microbes on your hands. Keep one in your bag and use it when you’re not able to get to a bathroom.

Article adapted from The New York Times and The Guardian.