For years, hospitals were reluctant to allow visitors or even staff to use cell phones over unfounded fears that the radio signals could interfere with sensitive medical equipment. Now, there may be a real risk associated with cell phones in hospitals: mobile devices carry all kinds of bacteria, some of them resistant to multiple antibiotics.

According to a study in the June issue of the American Journal of Infection Control, cell phones carried by patients and visitors were nearly twice as likely as the mobile phones of health workers to carry pathogens. Patient phones also tested for higher rates of multidrug-resistant bacteria, including MRSA.

Researchers in the Department of Medical Microbiology at Inonu University in Turkey tested the keypads, microphones and earpieces of 200 cell phones—67 from hospital employees and 133 from patients and other hospital visitors. They found harmful bacteria on 39.6 percent of patient phones and 20.6 percent of phones belonging to workers. None of the employees' phones contained resistant strains of bacteria, the researchers said, but seven patient phones did.

This, according to the Turkish research team, suggests that infection control efforts are working for healthcare personnel and need to be extended to patients and hospital visitors.

"The types of bacteria that were found on the patients' [phones] and their resistance patterns were very worrisome," the study said. "Some investigators have reported that cell phones of medical personnel may be a potential source of bacterial pathogens in the hospital setting."

The authors say that hospital-acquired infections affect at least a quarter of inpatients in developing countries such as Turkey. In the U.S., 1.7 million such infections cause an estimated 100,000 deaths annually.