Gene sequences and specific detection for Panton-Valentine leukocidin

Abstract

A new category of methicillin-resistant Staphylococcus aureus (MRSA), called community-acquired MRSA (CA-MRSA), has emerged worldwide. In contrast to previous MRSA, most CA-MRSA carries the Panton-Valentine leukocidin (PVL) genes ( luk PV SF) as a virulence genetic trait. Sequence analysis of the luk PV SF gene of a Japanese isolate demonstrated that the gene has more similarity to methicillin-susceptible S. aureus from France than MRSA from the United States. Based on the sequences, we developed a real-time PCR assay for the three key genes of CA-MRSA; that is, luk PV SF, mecA (for methicillin resistance), and spa (for S. aureus). Dual or triple assay for luk PV SF, mecA, and spa in one test tube became possible. The detection limit of the assay with probe and SYBR Green methods was between 2.7 and 2.7 × 10 1 CFU/ml. The assay detected PVL-positive MRSA in clinical (blood) isolates.