导致不同感染类型的MRSA杀白细胞毒素产量的体外测定
Clinical Infectious Diseases 2007;45:1550–1558MAJOR ARTICLE
In Vitro Production of Panton-Valentine Leukocidin among Strains of Methicillin-Resistant Staphylococcus aureus Causing Diverse Infections导致不同感染类型的MRSA杀白细胞毒素产量的体外测定
Stephanie M. Hamilton,1
Amy E. Bryant,1,3
Karen C. Carroll,4
Vivian Lockary,2
Yongsheng Ma,1
Eric McIndoo,1
Loren G. Miller,5
Francoise Perdreau-Remington,6
John Pullman,7
George F. Risi,8
Daniel B. Salmi,1 and
Dennis L. Stevens1,3
1Veterans Affairs Medical Center and 2State of Idaho Bureau of Laboratories, Boise, Idaho; 3University of Washington School of Medicine, Seattle; 4Division of Infectious Diseases and Medical Microbiology, Johns Hopkins Medical Institution, Baltimore, Maryland; 5Department of Internal Medicine, Division of Infectious Diseases and HIV Medicine, Harbor-UCLA Medical Center, Torrance, and 6San Francisco General Hospital, University of California, San Francisco; and 7Mercury Street Medical Group, Butte, and 8Christus St. Patrick Hospital, Missoula, Montana
Received 23 May 2007; accepted 21 August 2007; electronically published 6 November 2007.
Reprints or correspondence: Dr. Dennis L. Stevens, Infectious Diseases Section, Research Service, Dept. of Veterans Affairs Medical Center, 500 W. Fort St., Bldg. 45, Boise, ID, 83702 (dlsteven@mindspring.com).
Background.Community-acquired methicillin-resistant Staphylococcus aureus strains have recently been associated with severe necrotizing infections. Greater than 75% of these strains carry the genes for Panton-Valentine leukocidin (PVL), suggesting that this toxin may mediate these severe infections. However, to date, studies have not provided evidence of toxin production.
Methods.Twenty-nine community-acquired methicillin-resistant Staphylococcus aureus and 2 community-acquired methicillin-susceptible S. aureus strains were collected from patients with infections of varying severity. Strains were analyzed for the presence of lukF-PV and SCCmecA type. PVL production in lukF-PV gene–positive strains was measured by ELISA, and the amount produced was analyzed relative to severity of infection.
Results.Only 2 of the 31 strains tested, 1 methicillin-resistant Staphylococcus aureus abscess isolate and 1 nasal carriage methicillin-susceptible S. aureus isolate, were lukF-PV negative. All methicillin-resistant Staphylococcus aureus strains were SCCmec type IV. PVL was produced by all strains harboring lukF-PV, although a marked strain-to-strain variation was observed. Twenty-six (90%) of 29 strains produced 50–350 ng/mL of PVL; the remaining strains produced PVL in excess of 500 ng/mL. The quantity of PVL produced in vitro did not correlate with severity of infection.
Conclusions.Although PVL likely plays an important role in the pathogenesis of these infections, its mere presence is not solely responsible for the increased severity. Factors that up-regulate toxin synthesis in vivo could contribute to more-severe disease and worse outcomes in patients with community-acquired methicillin-resistant Staphylococcus aureus infection.
页:
[1]