Risk of Contamination of the Wound in a Hydrotherapeutic Tank.

Stanwood W, Pinzur MS (Department of Orthopaedic Surgery, Loyola University Medical Center, Maywood, III), Foot Ankle Int. 1998;19:173-176.

This study investigated the incidence of Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli organisms in cultures taken from hydrotherapeutic tanks (whirlpools) in order to assess the efficacy of 2 different cleaning methods used in the physical therapy departments of 2 different institutions located on the same academic campus.

Over a 4-week period each Monday, Wednesday, and Friday, cultures were taken using a sterile cotton swab dipped in thioglycolate before the tanks were filled in the morning and after the final cleaning at the end of the day. A total of 96 samples were taken, 48 from a university hospital and 48 from a Department of Veterans Affairs medical center. At each site, 24 samples were taken from the floor of the tank near the drain and 24 were taken from the agitator. The samples were plated onto standard blood agar plates and incubated for 48 hours before being examined for pathogens.

The cleaning protocol for the hydrotherapeutic tanks at the university hospital consisted of scrubbing and rinsing the tanks and agitators with a solution of 2 ounces of Cen-Kleen IV in 1 gallon of water for 2 minutes, scrubbing and rinsing the tanks again for 2 minutes using a solution of one-third bleach and two-thirds water, rinsing the tank and running the agitator for 5 minutes with bleach, and rinsing the tank again. At the Department of Veteran Affairs medical center, Sanizene was used to scrub the tanks and the agitator. The agitator was then run for 10 minutes in a bucket of Sanizene solution and the tank was rinsed.

The authors found that coagulase negative S aureus was the most common organism cultured from both institutions, at both the drain and the agitator and at both times of day. At the university hospital, P aeruginosa was identified in 6 of 12 samples taken from the agitator in the morning and 2 of 12 samples taken in the evening. At the Department of Veterans Affairs medical center, S aureus was identified in 1 of 12 samples taken from the agitator in the evening and 2 of 12 samples taken near the drain in the morning. These differences between institutions were statistically significant for S aureus and P aeruginosa. Of 96 samples, only 11 (11.5%) were positive for S aureus, P aeruginosa, or E coli. Of these 11 positive cultures, 9 were taken at the agitator site. Only 2 of the 96 cultures taken from the floor of the tanks near the drain were positive for these 3 pathogens.

Based on their findings, the authors believed that the 2 cleaning protocols were both effective in disinfecting the hydrotherapeutic tanks. They also suggested that patients with open and infected or contaminated wounds are unlikely to risk further contamination by being placed in a hydrotherapeutic tank, especially if the infected wound is not placed near the agitator jet.

Teresa M Hoeberlein-Miller, PT State University of New York at Brooklyn Brooklyn, NY