Multidrug-resistant methicillin-resistant Staphylococcus aureus (MRSA) strain in a men-who-have-sex-with-men (MSM) community in the United States: comment

The community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone known as ST8, t008 or USA300 is widespread in the United States (US) [1] and has been reported from Canada [2] and from several European countries [3-8]. It is characterised by a particular pulsed-field gel electrophoresis (PFGE) pattern, staphylococcal protein A (spa) type t008, multi locus sequence type 8 (ST8), Staphylococcal Cassette Chromosome mec (SCCmec) type IVa and encoding Panton-Valentine leukocidin (PVL). It can cause severe skin and soft tissue infections, endocarditis, sepsis, (necrotizing) pneumonia and neonatal death, and is spread by skin-to-skin contact. Transmission has been observed via contact sports [9,10] and in prison inmates [11], and it has now become a common cause of hospital-acquired infection in US hospitals [12,13]. In recent years, relatively large outbreaks of severe skin infection in men who have sex with men (MSM) caused by MRSA strains with the PVL gene were reported from the US [14-17]. In Europe, severe infections with PVL-positive S. aureus strains have been reported from France, Scotland, Sweden and the Netherlands [18]. Some, but not all, were in MSM. A study due to be published in the 19 February issue of Annals of Internal Medicine [19] has received prominent attention in the world's media this week, because it concludes that infection with multidrug-resistant USA300 (ST8) MRSA is common among MSM in San Francisco and Boston, and that infection may be sexually transmitted within the MSM community. Clinical manifestations include infections of the buttocks, genitals and the perineum. Male-male sex and previous MRSA infection are found to be independently associated with acquiring the multidrug-resistant strain. The same strain was also found in a homosexual man in Boston suggesting sexual transmission. HIV infection appeared not to be independently associated with the specific clone. .