Microbial Sequencing Analyses Suggest the Presence of a Fecal Veneer on Indoor Climbing Wall Holds S. L. Bra ¨uer • D. Vuono • M. J. Carmichael • C. Pepe-Ranney • A. Strom • E. Rabinowitz • D. H. Buckley • S. H. Zinder Received: 28 March 2014 / Accepted: 6 May 2014 Ó Springer Science+Business Media New York 2014 Abstract Artificial climbing walls represent a unique indoor environment in which humans interact closely with a variety of surface types. Climbing wall holds may mediate transmission of organisms between individuals, and yet there are no studies that identify microorganisms present on these surfaces. In the current study, the micro- organisms found on climbing wall holds were character- ized by analysis of amplified SSU rRNA gene sequences. In contrast to many other studies of built environments, the majority of microorganisms on holds were most closely related to microbes annotated as being recovered from environmental sources, such as soil, with human skin also representing an important source. Regional patterns were evident as rRNA gene sequences from the marine cyano- bacterium Prochlorococcus were abundant in gyms found within 16 km of the ocean. Enterobacteriaceae were present on 100 % of holds surveyed, and the members detected are commonly associated with fecal matter. Introduction In Western countries, most people spend the vast majority of their lives indoors [33, 34]. Microorganisms within these built environments can be introduced by people, pets, food, water, and air [4], and recent studies have indicated that humans (particularly skin, nostrils, and hair) are the pri- mary contributors to microbial communities in classrooms [28], kitchens [21], bathrooms [20], office buildings [26, 46], subway systems [47], shopping centers [52], and hospitals [27, 32]. Indeed, temporal changes in aerosolized microbial load have been correlated with human density in subway systems [16]. Similarly, human-associated bacteria were relatively more abundant in occupied versus unoc- cupied classrooms at the University of Oregon [38], emphasizing the importance of human presence in con- tributing to microbial dispersal in indoor environments. Climbing gyms are a unique environment where climbers tightly grip handholds that generally have a rough S. L. Bra ¨uer (&) Á M. J. Carmichael Á A. Strom Department of Biology, Appalachian State University, Boone, NC 28608, USA e-mail: brauersl@appstate.edu S. L. Bra ¨uer Á D. Vuono Á C. Pepe-Ranney Á D. H. Buckley Á S. H. Zinder Microbial Diversity Summer Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA D. Vuono Department of Civil and Environmental Engineering, Colorado School of Mines, Golden, CO 80401, USA Present Address: M. J. Carmichael Department of Biology, Wake Forest University, Winston-Salem, NC 27109, USA C. Pepe-Ranney Á D. H. Buckley Department of Crop and Soil Science, Cornell University, Ithaca, NY 14853, USA E. Rabinowitz Department of Health, Leisure and Exercise Science, Appalachian State University, Boone, NC 28608, USA S. H. Zinder Department of Microbiology, Cornell University, Ithaca, NY 14853, USA 123 Curr Microbiol DOI 10.1007/s00284-014-0643-3