Bacterial contamination of covered versus non-covered plates in a sterile operating room in an equine referral center.

Abstract: Surgical site infections (SSI) are a common postoperative complication of equine orthopedic surgery and often increase morbidity and mortality. Objective: This study aimed to determine if covering surgical instruments during surgery decreased bacterial environmental air contamination during early opening of surgical packs (EOSP). The authors hypothesized that covering instruments with sterile surgical towels would reduce the total number of bacterial colonies to which the instruments were exposed. Methods: Blood agar plates (BAP) were allocated into two groups (non-covered vs. covered with a sterile huck towel), tested in triplicate, and were exposed to environmental operating room air on sterile surgical instrument tables during 6 orthopedic procedures. Exposure time points for BAP groups were 0, 30, 60, 90, and 120 min; the 120 min time point was used for bacterial speciation to identify the most common bacteria colonies present. Results: Non-covered BAP contained more colonies than covered at 30 [mean non-covered colonies ± standard deviation; 7.9 ± 7.2], 60 [11±7.9], 90 [16.7 ± 11.3], and 120 [20.3 ± 14.7] min (p < 0.01). Gram-positive coccus were the most identified bacteria during speciation, however, many of the bacterial species identified are not commonly reported in equine postoperative SSI. Conclusions: These results suggest that covering instruments with a sterile huck towel may reduce bacterial air contamination from 30 to 120 min of operating time. Covering surgical instruments with a sterile towel or drape may aid in reducing bacterial contamination or colony counts when utilizing EOSP in equine surgical cases. Future studies aiming to correlate air contamination with equine SSI would be beneficial.