Sir

Your News story “Defence work sheds light on hospital bacteria” (Nature 428, 457; 200410.1038/428457a) reported that a British company is developing a luciferase-based test to detect methicillin-resistant Staphylococcus aureus (MRSA) directly from patient samples.

According to your News story this new assay could be performed in a few hours, whereas other MRSA tests take days. This is not accurate. For example, a Swiss team has published a six-hour assay combining immunomagnetic enrichment of S. aureus cells with real-time polymerase chain reaction (PCR) amplification of species-specific and resistance genes (P. François et al. J. Clin. Microbiol. 41, 254–260; 2003).

More recently, our group developed a real-time PCR assay that was shown to be sensitive and specific for the detection of MRSA within one hour directly from nasal swabs (A. Huletsky et al. J. Clin. Microbiol. 42, 1875–1884; 2004). A commercial version of this test, manufactured by Infectio Diagnostic, has now been approved by the regulatory authorities of Canada and the United States and is available on the North American market for the diagnosis of MRSA carriers (http://www.infectio.com). It will soon be marketed in Europe.

The healthcare burden imposed by resistant bacteria is alarming. The use of clinically validated tests for the rapid diagnosis of MRSA is essential to improve management of antibiotic resistance in hospitals.