Background: Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for one-third of infectious outbreaks reported among competitive athletes at high school and collegiate levels of competition, while the frequency of infections among National Football League players is nearly 400-fold higher than in the general population. The increased prevalence of MRSA infections among such athletes necessitates the study of football-specific environments as MRSA reservoirs.
Hypothesis: The recovery and viability of MRSA will differ between turf infill and turf fibers.
Study design: Descriptive laboratory study.
Level of evidence: Level 4.
Methods: Each of 6 infill types and 3 turf fiber types were inoculated with MRSA, sacrificed over time, and enumerated after bacteria extraction and dilution plating to determine the incubation time at which 50% of inoculated MRSA are recoverable and viable (here termed A50). The role of infill toxicity on MRSA survival was assessed using a dialysis assay.
Results: On average, MRSA was available for up to 96 hours on infill (average A50: 13 hours) and 24 hours on turf fibers (A50: 4 hours) (P < 0.001). The A50 for each infill type was also variable among infill groups (P < 0.001), averaging 2 hours (ethylene propylene diene monomer [EPDM] rubber), 7 hours (cork-based material), 9 hours (polymer-coated materials), 12 hours (crumb rubber), 13 hours (thermoplastic elastomer [TPE] rubber), and 27 hours (sands). MRSA remained available on slit-film and nylon fiber types for 12 hours postdeposition and for 24 hours on monofilament fibers. Toxicity assays showed that over 90% of MRSA cells remained viable after 6 hours of exposure to cork infill and sands, while 79%, 71%, 68%, and 17% of MRSA remained viable after exposure to polymer-coated materials, crumb rubber, TPE rubber, and EPDM rubber, respectively. Our data also indicated that organic and sand infills exhibited minimal toxicity to MRSA, while high relative toxicity drives limited MRSA availability in EPDM rubber infill.
Conclusion: MRSA recovery and viability varied among infill types but not among differing turf blades.
Clinical relevance: The results of this study can inform appropriate athlete and field management practices.
Keywords: MRSA; infill; methicillin-resistant Staphylococcus aureus; survival; turf.