Healio
Healio
October 05, 2009
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PVL linked with heightened S. aureus disease severity in children

Children with staphylococcal scarlet fever caused by Panton-Valentine leukocidin–positive Staphylococcus aureus strains had more exacerbated skin manifestations and greater systemic inflammatory responses compared with children who had strains that were negative for the cytotoxin.

“Clinical improvement after incision and drainage was achieved for most children with staphylococcal scarlet fever caused by Panton-Valentine leukocidin (PVL)–positive methicillin-resistant S. aureus strains, despite treatment with an ineffective antibiotic,” wrote the researchers from the Tri-Service General Hospital at the National Defense Medical Center in Taipei, Taiwan.

This is the first study conducted to prospectively compare children with staphylococcal scarlet fever with and without the presence of PVL, according to the researchers.

The researchers compared clinical characteristics and lab findings among 49 children who were treated for staphylococcal scarlet fever caused by community-associated S. aureus isolates during an 11-year study period and used multivariate analysis to determine the following:

  • 26 children had a methicillin-susceptible S. aureus isolate; 23 had a methicillin-resistant isolate.
  • 24 isolates, including five MSSA and 19 MRSA, were positive for PVL; 25 isolates (21 MSSA, 4 MRSA) were negative for PVL.
  • Children with PVL–positive isolates had significantly larger abscess sizes; higher white blood cell counts; higher C-reactive protein levels; and longer durations of fever, generalized scarlatiniform rashes and hospital stays.
  • Among the 19 PVL–positive MRSA isolates, 17 carried the staphylococcal cassette chromosome mec VT and all were multilocus sequence type 59.
  • Staphylococcus enterotoxin B was most common, with 92% of all isolates (23 MSSA, 22 MRSA) containing only that toxin.

Despite initiating antibiotic therapy within 24 hours of hospital admission for all patients, initial antibiotics were effective in only 53% of the patients; however, the researchers noted no significant association between ineffective antimicrobial therapy and clinical outcome.

Lo W-T. Clin Infect Dis. 2009;49:e69-e75.