People not washing their hands after going to the toilet, rather than
undercooked meat, is behind the spread of a key strain of E. coli.
Experts looked at thousands of blood, faecal and food samples.
They found human-to-human transmission was responsible - "faecal particles from
one person reaching the mouth of another".
Public Health England said hand-washing and good hygiene were key to preventing
the spread of infections.
There are many different strains of E. coli. Most are harmless but some can
cause serious illness.
Antibiotic-resistant E. coli is increasingly common. Strains which have
'Extended Spectrum Beta-Lactamases (ESBLs) - enzymes that destroy penicillin
and
another antibiotic, cephalosporin - are causing particular concern.
E. coli is the most common cause of blood poisoning, accounting for about one
third of cases in the UK, with ESBL strains accounting for around 10% of those
- around 5,000 a year
'Little crossover'
In the study, published in Lancet: Infectious Diseases, the team analysed
20,000 human faecal samples and 300 blood samples plus hundreds of sewage
samples,
animal slurry and meats including beef, pork and chicken - as well fruit and
salad.
One strain - ST131 - was seen in the majority of human samples from all three
sources. It is found in the gut but can, usually via urinary tract infections,
cause serious infections.
However, the strains found in meat, cattle and animal slurry were mostly
different.
Prof David Livermore, from the University of East Anglia's Norwich Medical
School, who led the research, said: "Critically - there's little crossover
between
strains from humans, chickens and cattle.
"Rather - and unpalatably - the likeliest route of transmission for ESBL-E.
coli is directly from human to human, with faecal particles from one person
reaching the mouth of another."
He said maintaining food hygiene was still important - people should handle raw
meat carefully, not least because there are other strains of food-poisoning
bacteria that come through the food chain.
But he added: "Here - in the case of ESBL-E. coli - it's much more important to
wash your hands after going to the toilet.
"It's particularly important to have good hygiene in care homes, as most of the
severe E. coli infections occur among the elderly, and people may need help
going to the toilet."
Prof Neil Woodford, of Public Health England, said: "In order to tackle
antibiotic resistance, we not only need to drive down inappropriate
prescribing, but
reduce infections in the first place.
"In order to limit serious, antibiotic resistant E. coli bloodstream
infections, we must focus on thorough hand-washing and good infection control,
as well
as the effective management of urinary tract infections."