1. Seasonal Variation in the Prevalence of Coagulase-Positive Staphylococcus aureus Among College Students (2007-2009) Megan Branche Dr. Carolyn Mathur, Mentor INTRODUCTION METHODS RESULTS DISCUSSION CONCLUSION LITERATURE CITED ACKNOWLEDGEMENTS OBJECTIVES  Staphylococcus aureus (Sa) is a gram positive salt- loving pathogen that has the ability to produce enzymes coagulase and β-lactamase.  Coagulase causes agglutination and allows the pathogen to hide in blood clots and remain undetected by the immune system.  β -lactamase has the ability to break the β -lactam rings of antibiotics such as Penicillin and Methicillin, causing it to be resistant (MRSA).  Those with suppressed immune systems and prior antibiotic exposure are more susceptible to infection (Awad et al. 2007 and Graffunder and Venezia 2002).  32% of the U.S. population was colonized with Sa in 2002 (Kuehnert et al 2006).  Sa infections in different forms have been increasing over time (Jhung et al. 2008).  Determine if there is seasonal variation in the prevalence of coagulase-positive Sa (CpSa) among college students  Determine if the prevalence of CpSa increased among college students between 2007-2009  Determine if gender, participation in athletics, or working in the healthcare field increased the prevalence of CpSa among college students between 2007 and 2009. I would like to thank Dr. Mathur for all of her guidance and patience with the project. I would also like to thank Sam Giordano, Chad Taylor, Angel Newson, and Ryan Cheng for their aide in data collection and Mike Williams and Chelsea Varner for their assistance. Inoculation on mannitol salt agar plates Positive samples tested for coagulase using Bactistaph kit Coagulase positive samples tested for β-lactamase using kit Nasal swab sample http://pathmicro.med.sc.edu/Infectious%20Disease/staph%20aureus%202.jpg http://www.health-news-blog.com/images/blogs/3-2008/staph-aureus -bacteria-16790.jpg Incubation in m-staph enrichment broth RESULTS http:// images.google.com/imgres?imgurl=http://faculty.mc3.edu/jearl/ML/msa.jpg&imgrefurl=http://faculty.mc3.edu/jearl/ML/ml-8.htm&usg=__TZI Figure 4. Total number of students sampled for each semester, and the amount of coagulase positive and β-lactamase positive samples. The semester comparisons were not significant. Figure 5. Percent of coagulase positive samples per semester. The spring semesters both have higher percentages than the fall semesters. Figure 6. Percent of coagulase positive samples per category. The categories did not have a significant affect on colonization.  The overall prevalence of coagulase positive S. aureus samples (29.9%) did not differ significantly from the percentage (32%) reported from Kuehnert et al 2006.  A seasonal variation of colonization is suggested in comparing all fall semesters to both spring semesters.  Gender, athletics, and a job in healthcare did not affect colonization.  The production of β-lactamase remained low over time in those sampled, indicating that the coagulase positive samples are not antibiotic resistant.  The prevalence of coagulase positive samples did not increase over time. Data collection will continue for future analysis.  A seasonal variation, with higher prevalence in the spring semester, was observed. http://www.hardydiagnostics.com/catalog2/user/ProductDetails.asp?poid=BR066A  Crum, N., et al. 2006. Fifteen-Year Study of the Changing Epidemiology of Methicillin-Resistant Staphylococcus aureus. The American Journal of Medicine. 119:943-951.  Graffunder, E., and Venezia, R. 2002. Risk factors associated with nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection including previous use of antimicrobials. Journal of Antimicrobial Chemotherapy.49:999-1005.  Jhung, MA., et al. “Enhanced Detection of Staphylococcus aureus-related Hospitalizations Using Administrative Databases, United States-1999-2005.” Powerpoint presentation. Centers for Disease Control and Prevention. April 2008.  Kuehnert, M., et al. 2006. Prevalence of Staphylococcus aureus Nasal Colonization in the United States, 2001-2002. JID. 193:172-179.  Newson, Angel. Is the Prevalence of Staphylococcus aureus increasing Among York College Students? Senior Thesis Project 2008.  Taylor, Chad. Prevalence of Staphylococcus aureus Among Students at York College of Pennsylvania. Senior Thesis Project. 2008. Figure 2. Percent of coagulase positive samples per year. An overall percentage of 29.9% positive samples was observed. Figure 3. Percent of coagulase positive samples per season. This was found to be significant with a p value = 0.0145 using a Chi square test for independence. Figure 1. Types of Sa infections increasing over time (Jhung et al. 2008). Department of Biological Sciences, York College of Pennsylvania