One in four cases of hospital MRSA bacteraemia occurs in new arrivals

One in four cases of MRSA blood stream infection in hospital occur in patients who have just arrived from the community. These patients tend to be older and have been in hospital before.

These results, published on bmj.com, should help to refine infection control policies in UK hospitals.

In the past 10 years, MRSA infection has increased in the United Kingdom. The bacterium can infect many sites; one serious form of infection is that in which blood-stream infection occurs (bacteraemia). A national surveillance scheme counts MRSA bacteraemia by hospital trust, but it has not yet addressed whether cases of MRSA bacteraemia are arriving in hospitals from the community.

Researchers at the University of Oxford analysed methicillin resistant Staphylococcus aureus (MRSA) and methicillin sensitive Staphylococcus aureus (MSSA) bacteraemia in patients on arrival in two Oxfordshire hospitals over a seven year period (1997 to 2003).

At one hospital, patients admitted from the community accounted for 49% of total MSSA cases and 25% of total MRSA cases. The proportion of methicillin resistance among patients admitted with Staphylococcus aureus bacteraemia, rose from 14% in 1997 and 1998 to 26% in 2003.

Most patients (at least 91%) admitted with MRSA bacteraemia had previously been in hospital, half had never had MRSA detected before, and 70% were admitted to emergency medical and surgical services. A similar pattern was observed in the other hospital.

Despite some study limitations, the authors conclude that, of the cases of MRSA bacteraemia detected in hospital, a quarter occurs in patients who have just arrived from the community, and that this proportion is increasing. They call for additional research to be undertaken into the best way to recognise these patients.