Investigation of Bacterial Pathogens on 70 Frequently Used Environmental Surfaces in a Large Urban U.S. University


After reports of increased severity of bacterial infections from community institutions, a broad spectrum of 70 surfaces was sampled for potential bacterial pathogens in the morning and afternoon of one day per week over three consecutive weeks in a large U.S. university. Surfaces included public telephone mouthpieces, water fountain drains, student computer keyboards and desks, and buttons on elevators, vending machines, and photocopiers. A total of 420 samples was obtained. Bacterial counts were high on telephone mouthpieces, up to 168.8 colony-forming units (CFUs) cm2 of surface area. Stenotrophomonas maltophilia was isolated from 60% of fountain drains. Ninety percent of the keyboards showed positive bacterial cultures in the afternoon sampling. Staphylococcus aureus was identified on keyboards, telephone mouthpieces, and an elevator button. No S. aureus were methicillin-resistant. The swab sampling method reduced bacterial counts to less than or equal to 2.0 CFU cm2 on keyboards and telephone mouthpieces. Disinfectants for possible use in cleaning of telephones, water fountain drains, and keyboards are discussed.


Recent reports of life-threatening community-acquired bacterial infections emphasize the need to identify community surfaces that are rich in bacteria and have the potential to harbor pathogens (Libanore, Bicocchi, Pantaleoni, & Ghinelli, 2004; Romano, Lu, & Holtom, 2006). This study is the first to examine a broad array of surfaces in a large urban university in the midwestern United States. The United States is the world’s third largest country in population and the fourth largest country in area. The university location was chosen for its substantial population of primarily late-teens and early adults, within which athletes, immuno-compromised individuals, and drug users can be found. In this age group, personal hygiene habits are not always optimal, and this can lead to the spread of infectious diseases infectious diseases: see communicable diseases.  (Drankiewiez & Dundes, 2003; Scott & Vanick, 2007).

Environmental surfaces in communities may receive substantial traffic. Such surfaces may support bacterial growth and may or may not receive adequate cleaning. Determining the number of bacteria and screening for the presence of potential pathogens on surfaces are initial steps in maintaining the health of individuals contacting those surfaces.

Discussion and Conclusion

The data from this study show that in this large university community, the telephone mouthpieces showed the highest individual bacterial counts and had the highest numbers of bacteria compared to all other sampled surfaces except the drains…


Brooke, Joanna S.; Annand, John W.; Hammer, Angela; Dembkowski, Karen; Shulman, Stanford T.

Reprinted by permission from the Jan/Feb 2009 Issue of the Journal of Environmental Health, the official publication of the National Environmental Health Association (NEHA).

The Journal of Environmental Health is the official publication of the National Environmental Health Association (NEHA).