New strains of community-acquired methicillin-resistant Staphylococcus aureus with Panton–Valentine leukocidin causing an outbreak of severe soft tissue infection in a football team

Excerpt

A new category of methicillin-resistant Staphylococcus aureus (MRSA), designated community-acquired MRSA (CA-MRSA), has been noted increasingly in the community in the past 14 years [1]. CA-MRSA strains have different genetic backgrounds than hospital-acquired MRSA, as evidenced by pulsed-field gel electrophoresis (PFGE) patterns, and thus do not descend from nosocomial strains. They also carry a novel staphylococcal cassette chromosome (SCC) mec type IV element, which is differentiated from the hospital-acquired MRSA SCCmec types I-III by its smaller size and the absence of non-ß-lactam genetic resistance determinants. In addition, CA-MRSA strains replicate more rapidly than hospital-acquired MRSA strains, they have a better ability to colonize humans, and they possess genes for different toxins [2]. Major risk factors for CA-MRSA colonization, as recognized by Ellis et al. [3], are treatment with systemic antibiotics and skin trauma. The strains producing Panton–Valentine leukocidin cause furunculosis and severe necrotic hemorrhagic pneumonia in otherwise healthy individuals [3, 4]. Outbreaks have been described in day-care and athletic settings. Sport teams are especially vulnerable to infections with these strains because of frequent skin trauma and close contact of team members [4]. In order to detect outbreaks of new CA-MRSA, molecular typing [5‐8] should be performed and virulence genes detected [9]. Reported here is an outbreak of severe soft tissue infection affecting a football team, which was caused by a new strain of community-acquired methicillin-resistant Staphylococcus aureus carrying the Panton–Valentine leukocidin gene. …