We found a virulent closely related clone (Panton-Valentine leukocidin-positive, SCCmec V:ST59) of methicillin-resistant Staphylococcus aureus in inpatients and outpatients in Taiwan. The isolates were found mostly in wounds but were also detected in blood, ear, respiratory, and other specimens; all were susceptible to ciprofloxacin, gentamicin, and trimethoprim-sulfamethoxazole.

Among 10 strains of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolated in 2002 from patients with skin infections, seven harbored the Panton-Valentine leukocidin gene, two harbored the exfoliative toxin A gene, and one harbored neither of these genes. CA-MRSA isolates producing a variety of exotoxins are currently spreading in the Swiss community.

Three patients with extensive necrotizing pneumonia due to Panton-Valentine leukocidin-positive Staphylococcus aureus strains and with aggravating factors (leukopenia count of less than 3x10(9)/liter in all three cases and hemoptysis in two cases) were successfully treated with toxin-suppressing agents introduced rapidly after hospital admission.

We studied 12 Staphylococcus aureus isolates causing tropical pyomyositis in the Amazon Basin of Peru. All isolates were methicillin-susceptible; 11 carried Panton-Valentine leukocidin-encoding genes, and 5 belonged to multilocus sequence type 25 and possessed an extensive set of enterotoxins. Our findings suggest sequence type 25 is circulating in tropical areas of South America.

Invasive and skin community-associated (CA)-methicillin-resistant Staphylococcus aureus isolates from children were matched with invasive CA-methicillin-sensitive S. aureus strains during 2000-2004. Isolates were analyzed for presence of Panton-Valentine leukocidin. A USA400 lineage clone (n = 6) and the predominant USA300 lineage clone emerged.

This paper describes a fatal case of culture-confirmed, community-associated methicillin-resistant Staphylococcus aureus (MRSA) pneumonia in an 8-month-old child in Hong Kong in 2001. Stored cytological materials prepared from the pleural fluid were retrieved for molecular analysis. The result indicates the presence of a Panton-Valentine leucocidin-positive, spa type 019 MRSA.

We examined the capacity of Staphylococcus aureus strains to release Panton-Valentine leukocidin (PVL) in the presence of antibiotics. No PVL was detected when S. aureus was incubated at inhibitory concentrations, while subinhibitory concentrations of oxacillin enhanced the PVL level; clindamycin, linezolid, and fusidic acid were inhibitory; and vancomycin had roughly no effect.

DONALD E. PAGLIA, WILLIAM N. VALENTINE AND DONALD L. RUCKNAGEL with the technical assistance of MARY Lu WILSON and JULIE WITTENBERG Departments of Medicine and Pathology, Centerfor the Health Sciences, University of California, Los Angeles; Research and Medical Services, Veterans Administration Center, Los Angeles, Culifornia; and Department of Human Genetics, University of Michigan Medical Sch...