By sequencing the entire genomes of methicillin-resistant Staphylococcus aureus (MRSA) bacteria isolated from patients to detect subtle genetic differences in the isolates, British scientists have succeeded in tracking the patient-to-patient transmission of MRSA, a feat that they hope will help improve control and prevention of this pathogen (Harris SR et al. Science. 2010;327:469-474).
The researchers collected 20 isolates of a common MRSA strain called ST249 from patients at a single hospital in Thailand who became infected within 7 months of each other. DNA sequencing revealed that 5 isolates were extremely similar; the isolates were from patients located in adjacent wards of the hospital, suggesting person-to-person transmission. The other isolates were more genetically diverse and were unlikely to have been caused by in-hospital transmission.
Stephenson J. Tracking MRSA. JAMA. 2010;303(7):603. doi:10.1001/jama.2010.151