Tracking the Prevalence of Staphylococcus aureus Among York College Students: Corinne Cusick & Dr. Carolyn Mathur Department of Biological Sciences, York College of Pennsylvania Introduction Staphylococcus aureus (Sa) is a Gram positive bacterium that produces coagulase while virulent (Benson 2002). Coagulase positive Staphylococcus aureus (CPSa) is associated with nosocomial skin and soft tissue infections that could lead to death if untreated. Community-acquired CPSa (CA-CPSa) is commonly carried in the nasal passages and spreads easily in schools, fitness centers and community centers. CA-CPSa is brought into hospitals via outpatients and is adding to the hospital-acquired CPSa (HA-CPSa) infections that are already occurring (Huang et al. 2006). Change in seasons has known effects on the prevalence of rhinovirus, or the common cold (Olenec et al. 2010), and possible effects on the prevalence of CPSa. In comparing test results, previous experiments have concluded that gender is not a conditioning variable in CPSa prevalence; this is due to annual variation in the gender with the highest CPSa pecentage (Branche 2009), (Newson 2008), (Taylor 2007). Objectives Continue an ongoing study which began in 2007 of the prevalence of CPSa at YCP. Determine if gender, gym-activity or working in healthcare increases the prevalence of CPSa among York College students between 2007 and Determine if there is a seasonal variation in the prevalence of CPSa in YCP students. Determine if prevalence of CPSa at YCP has changed from 2007 to Methods Conclusion Staphylococcus aureus (Sa) is present in the York College community and has been for at least the past four years. Gender differences may reflect potential difference in personal hygiene (Stevens et al. 2010). Sa prevalence is not greater in students who work in healthcare professions than those who do not. Students who attend the gym do not have a greater chance of infection by Sa than those who do not. Contrary to the 2009 results (Branche), further data indicates that the chance of infection by Sa is not seasonal. From the first semester of this study in 2007 to the current sampling in 2011, YCP averages 27.13% Sa prevalence out of the total number of test subjects. This average is comparable to the national range of 25% to 30% (Centers for Disease Control and Prevention [CDC], 2011). Results Figure 1. Compiled coagulase positive nasal samples from 2007 to 2011 divided into genders, gym or healthcare activities. Prevalence of CPSa among groups was compared with a Fisher’s Exact two-tailed test. a)Prevalence of CPSa was greater in males than females (P=0.03). b)There was no difference between healthcare workers (HC) and non- healthcare workers (NHC) (p-value=0.3616). c)There was no difference between gym (G) and non-gym (NG) (p-value=0.1258). Values on top of each bar equals sample size. Figure 3. Compiled coagulase positive nasal samples by semester from 2007 to There was no difference in the prevalence between the semesters (p- value=0.8930). Literature Cited Benson, H. J. (2002). The Staphylococci: Isolation and Identification. In Microbiological Applications: Laboratory Manual in General Microbiology (8 th ed., pp ). New York, NY: McGraw Hill. Branche, M. (2009). Seasonal Variation in the Prevalence of Coagulase- Positive Staphylococcus aureus Among College Students ( ). Senior Thesis Project. Centers for Disease Control and Prevention. (2011). Definition of MRSA. Retrieved November 21, 2011 from Huang, H., Flynn, N.M., King, J.H., Monchaud, C., Morita, M., Cohen, S.H. (2006). Comparisons of Community-Associated Methicillin-Resistant Staphylococcus aureus (MRSA) and Hospital-Associated MSRA Infections in Sacramento, California. Journal of Clinical Microbiology, 44(7), Newson, A. (2008). Is the Prevalence of Staphylococcus aureus Increasing Among York College Students? Senior Thesis Project. Olenec, J.P., Kim, W.K., Lee, W., Vang, F., Pappas, T.E., Salazar, L.E., Evans, M.D., Bork, J., Roberg, K., Lemanske, R.F., Gern, J.E. (2010). Weekly Monitoring of Children with Asthma for Infections and Illness During Common Cold Seasons. Journal of Allergy Clinical Immunology, 125(5), Stevens, A.M., Hennessy, T., Baggett, H.C.,Bruden, D., Parks, D., Klejka, J. (2010). Methicillin-Resistant Staphylococcus aureus Carriage and Risk Factors for Skin Infections, Southwestern Alaska, USA. Emerging Infectious Diseases, 16(5), Taylor, C. (2008). Prevalence of Staphylococcus aureus Among Students at York College of Pennsylvania. Senior Thesis Project. Acknowledgments I would like to thank Taylor, Newson, Cheng, Giordano, and Branche for providing Sa data since 2007 that contributes to the depth of my data set. Also thanks to Dr. Kleiner for his insightful suggestions and to Robert O’Neill for his proof reading. abc Figure 2. Compiled coagulase positive nasal samples from 2007 to There was no difference in prevalence between fall and spring (p-value=0.4247). Nose and skin samples collected from fall and spring Microbiology students. Grown in M- staphylococci broth Mannitol salt agar streaks Coagulase testingβ-lactamase testing