Severe community-onset pneumonia in healthy adults caused by methicillin-resistant Staphylococcus aureus carrying the Panton-Valentine leukocidin genes

Clin Infect Dis. 2005 Jan 1;40(1):100-7. doi: 10.1086/427148. Epub 2004 Dec 7.


Background: Recent worldwide reports of community-onset skin abscesses, outbreaks of furunculosis, and severe pneumonia associated with methicillin-resistant Staphylococcus aureus (MRSA) carrying Panton-Valentine leukocidin (PVL) genes and the staphylococcal cassette chromosome mec (SCCmec) type IV indicate that MRSA infections are evolving into a community-related problem. The majority of cases reported to date involve skin and soft-tissue infections, with severe pneumonia representing a relatively rare phenomenon. During a 2-month period in the winter of 2003-2004, four healthy adults presented to 1 of 2 Baltimore hospitals with severe necrotizing MRSA pneumonia in the absence of typical risk factors for MRSA infection.

Methods: Patients' MRSA isolates were characterized by strain typing with use of pulsed-field gel electrophoresis and SCCmec typing with use of a multiplex polymerase chain reaction (PCR) assay and detection of PVL genes by PCR.

Results: All 4 patients' MRSA isolates carried the PVL genes and the SCCmec type IV element and belonged to the USA300 pulsed-field type. These 3 findings are among the typical characteristics of community-onset MRSA strains. In addition, 2 of our patients had concomitant influenza A diagnosed, which likely contributed to the severity of their presentation.

Conclusions: To our knowledge, these patients represent the first reported North American adults with severe community-onset MRSA pneumonia caused by strains carrying the PVL genes.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bacterial Toxins
  • Bacterial Typing Techniques
  • Community-Acquired Infections / microbiology*
  • Exotoxins
  • Female
  • Humans
  • Leukocidins / genetics*
  • Male
  • Methicillin / pharmacology
  • Methicillin Resistance*
  • Middle Aged
  • Patient Selection
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology
  • Staphylococcus aureus / classification
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / genetics
  • Staphylococcus aureus / pathogenicity
  • Virulence Factors / analysis


  • Bacterial Toxins
  • Exotoxins
  • Leukocidins
  • Panton-Valentine leukocidin
  • Virulence Factors
  • Methicillin