Staphylococcus aureus dispersal from healthy volunteers.

Understanding Staphylococcus aureus dispersal from human carriers is vital for preventing transmission and colonization of this organism in healthcare settings. This study investigated the S aureus supershedder hypothesis in relation to attributes of healthy volunteers. Methods: Microbial aerosol generation from volunteers was quantified within a controlled environmental chamber during walking or sitting activities. Biological air samplers were used to determine numbers of total S aureus colony-forming units disseminated during these activities. Results: A total of 17 volunteers were sampled on 3 occasions. Hairstyle (long hair tied up or a shaved head) was the only significant predictor of dissemination of S aureus (5% significance level). No other significant effects were found at the 5% level. A negative binomial distribution provides the best fit with respect to S aureus. Conclusion: We found that, in the context of our small sample size, hairstyle (long hair tied up or a shaved head) statistically affected levels of bacteria shed from volunteers. However, we found no evidence for “supershedders” or “cloud adults,” suggesting they are at an extreme end of a continuous distribution.