Hospitals try to control Clostridium difficile, a bacterium that can cause deadly infections, by careful cleaning and meticulous washing of the hands. But limiting the use of antibiotics may be even more effective, a British study suggests.

The incidence of C. difficile infection in England declined by 80 percent after 2006, when strict hospital sanitation and antibiotic prescription controls were both implemented.

The study, in The Lancet, found that in regions where fluoroquinolone antibiotics were used widely, the more virulent and deadly resistant strains of C. diff became the dominant type of infection, while susceptible strains continued to enter the hospital from the community.

In areas where antibiotic use was restricted, infections with resistant strains largely disappeared, leaving only people infected with milder, and more easily treatable, nonresistant strains.

Both careful cleaning and antibiotic control are important, according to the senior author of the study, Dr. Mark Wilcox, a professor of microbiology at the University of Leeds. But, he said, “In a setting where the resistant strain is present, careful use of antibiotics is most effective.”