Of everyday objects, the common kitchen cutting board seems among the most harmless. Yet, scientists say some 3.5 percent of cutting boards found at home are contaminated with E. coli super-bacteria resistant to multiple types of antibacterial drug.

Cutting boards found in hospital kitchens are even worse, however, researchers from Switzerland found in a recent study of one of the kitchen’s indispensable tools. As many as 6.5 percent of hospital cutting boards were contaminated with the superbug, after kitchen workers had handled poultry.

“The spread of multi-drug resistant bacteria has been associated with the hospital setting, but these findings suggest that transmission of drug-resistant E. coli occurs both in the hospital and households,” Andreas Widmer said in a news release. “Our findings emphasize the importance of hand hygiene, not only after handling raw poultry, but also after contact with cutting boards used in poultry preparation.”

The study was published Sunday in the May issue of Infection Control and Hospital Epidemiology, the journal of the Society for Healthcare Epidemiology of America.

In the study, physician-researcher Widmer and her team examined 154 cutting boards from University Hospital in Switzerland along with another 144 from private homes, all of which had been used to prepare meat in the kitchen. The cutting boards, in addition to 20 sets of gloves used by food preparers at the hospital, were tested for ESBL-producing Enterobacteriaceae, a family of gram-negative bacteria that includes Salmonella, E. coli and Klebsiella.

Only cutting boards used to prepare poultry tested positive for any ESBL-producing bacteria, the researchers noted.

An infection by an ESBL-producing bacteria may be unstoppable by today’s antibiotics as multidrug-resistant bacteria continues to emerge as arguably this century’s most pressing public health threat. Varying activity against various types of cephalosporins — a class of antibiotic developed from fungus — helps to disguise the presence of the infection from doctors in the first place.

The choice of antimicrobial agent is critical early in treatment, the CDC says.