High Prevalence of Panton-Valentine Leukocidin in methicillin-susceptible Staphylococcus aureus in Camden, NJ
Methods: We prospectively collected MSSA isolates from diverse specimen sources from a tertiary care hospital in southern New Jersey over a one year period (2013). We tested isolates for pvl by PCR using published primers. Prevalence of pvl gene among MSSA isolates was correlated with specimen source and antibiotic resistance phenotype.
Results: We collected 134 MSSA isolates from blood (49), wound (44), nasal (14), respiratory (12), body and joint fluid (10), and other (5) sites. Overall 22 isolates had pvl (16.6%), including 13 wound, 5 blood, 2 body fluid, and 1 nasal and 1 urine isolates. Highest prevalence of pvl was among wound isolates (13/44, 29.5%). Erythromycin resistance (E-R) correlated strongly with pvl; 17 of 22 pvl-positive isolates were E-R (30% of all E-R isolates; p < 0.001). However Clindamycin resistance (C-R) did not correlate with pvl; only 2 of 22 pvl strains were C-R. 4 of 6 Levofloxacin-Intermediate isolates had pvl (p < 0.01).
Conclusion: Prevalence of pvl is increasing among MSSA from patients at a tertiary care center in southern New Jersey. Prevalence of pvl was highest in wound isolates, consistent with the pathophysiologic role of PVL in SSTIs. E-R but not C-R isolates were most likely to have pvl. The correlation of non-inducible macrolide resistance with pvl in this pool of MSSA isolates is similar to non beta-lactam resistance profiles of USA300 CAMRSA in our region. This is consistent with a hypothesis that pvl positive MSSA may evolve from USA300 CAMRSA by loss of mecA function via partial or complete deletion, and may explain a regional decline in proportion of CAMRSA in SSTI. Further genetic analysis of this collection of pvl positive MSSA is ongoing.
C. Knob, None