Project Director

Spratt, Henry G., Jr.

Department Examiner

Giles, David; Kovach, Margaret; Kutz, Beverly


Dept. of Biological and Environmental Sciences


University of Tennessee at Chattanooga

Place of Publication

Chattanooga (Tenn.)


Needle insertion into skin for the purpose of alleviating muscle pain began with the emergence of traditional Chinese medicinal (TCM) acupuncture. “Dry needling”, a recent alternative to acupuncture, involves inserting a monofilament needle down into the deep tissue of a patient’s skin in order to reach the affected muscle. Despite its effectiveness and low risk of infection, dry needling remains questionable with respect to its safety and the lack of research to confirm the low risk of bacterial transmission via the dry needling needles. In this microbiological study, highly concentrated Tryptic Soy Agar was utilized to simulate the elasticity of human skin, and the transmission of commensal and transient bacterial species into “deep tissue” (agar) was analyzed. Transmitted cells of varying overnight culture dilutions were examined along the needle insertion in the agar and further analyzed at each depth of agar using a confocal microscope. Results showed that while S. aureus growth decreased along the length of the needle stab after an increase in the dilution of the culture, E. coli cells showed significant growth even in the highest dilution. This could be due to E. coli’s motile properties and their rod shape, which provides more surface area and thus more binding units that can facilitate adhesion to the needle. Confocal images of E. coli cells also demonstrated a high concentration of cells transmitted. The behavior exhibited by E. coli could suggest a higher risk of infection via dry needling than the potential risk of a S. aureus infection, however, the number of E. coli cells that were transmitted were still not enough to cause an infection in the tissue. This study serves to support the hypotheses made in a few other studies that the risk of infection from dry needling is tremendously low, and also showcases the behavior of Staphylococcus aureus and Escherichia coli in a highly elastic environment.


Dr. Margaret Kovach Dr. David Giles Dr. Henry Spratt, Jr. Mrs. Beverly Kutz Dr. Ethan Carver PHYSICAL THERAPY STUDY PARTICIPANTS: Dr. David Levine Dr. Randy Walker Dacey Winkleman Zac Cooper Heather Harmon Brittany Rock


B. S.; An honors thesis submitted to the faculty of the University of Tennessee at Chattanooga in partial fulfillment of the requirements of the degree of Bachelor of Science.




Acupuncture; Myofascial pain syndromes -- Treatment


Microbiology; Bacteria; Dry needling; Acupuncture; E. coli; S. aureus



Document Type



52 leaves







Date Available


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Biology Commons