Prevalence and sequence variation of Pan ton-Valentine leukocidin
in methicillin-resistant and methicillin-susceptible Staphylococcus aureus strains in the United States.
In addition to the intrinsic virulence exhibited by ST398 MSSA in previous studies, the potential to acquire resistance to multiple classes of antimicrobial drugs (1,4,10), as well as virulence factors such as Panton-Valentine leukocidin
(8), warrants continued surveillance in light of recent ST398 methicillin-resistant S.
Nearly all CC1 (99%), CC8 (98%), and CC30 (100%) isolates were positive for Panton-Valentine leukocidin
(PVL); all isolates in these 3 CCs carried SCCmec IV.
First outbreak of methicillin-resistant Staphylococcus aureus USA300 harboring the Panton-Valentine leukocidin
genes among Japanese healthcare workers and hospitalized patients.
Moreover, MLST, SCCmec typing, agr typing, and pvl detection showed all strains to be positive for ST8, SCCmec IVa, agr I, and Panton-Valentine leukocidin
, which are typical characteristics of USA300 clones.
They correctly pointed out that several characteristics of the incriminated strain, including methicillin and tetracycline susceptibility, spa type, and the presence of genes encoding the Panton-Valentine leukocidin
(PVL), differed from the usual genetic features of strains isolated from livestock (3,4).
MRSA isolates were more likely to harbor the genes encoding Panton-Valentine leukocidin
than were MSSA isolates, 95.
aureus isolates were examined by pulsed-field gel electrophoresis, spa typing, and antimicrobial drug susceptibility testing and tested for the Panton-Valentine leukocidin
All 3 MRSA isolates were negative by PCR for the Panton-Valentine leukocidin
, toxic shock syndrome toxin 1, and exfoliative toxins A and B.
The community-associated MRSA strain USA300, which nearly always carries genes for the Panton-Valentine leukocidin
(PVL) and the staphylococcal cassette chromosome mec (SCCmec) type IV, became the predominant strain type of MRSA circulating in the United States by 2011 (5).
Nearly all MRSA isolates associated with livestock colonization lack the genes encoding Panton-Valentine leukocidin
(PVL) (Smith et al.
1999), detection of Panton-Valentine leukocidin
(PVL) toxin gene, and methicillin-resistance mecA gene detection by multiplex polymerase chain reaction (PCR) as described by McDonald and coauthors (2005).