Patients discharged from hospitals are commonly infected with methicillin-resistant Staphylococcus aureus (MRSA) and nearly 20% transmit the bacteria to the people they live with, according to new research.

Researchers screened 1,501 adult hospital patients for MRSA before discharge and found that 191 patients, or almost 13%, had acquired MRSA.

The study said that out of 188 household contacts that lived with the 191 MRSA patients who were discharged, 36 acquired MRSA, with older people and those caring for the infected person most at risk.

The study has been published in the August 2009 issue of the Archives of Internal Medicine.