Comparison of two different antiseptics regarding intracutaneous microbial load after preoperative skin cleansing in total knee and hip arthroplasty
The aim of the study was to compare the effectiveness of two commercially available alcohol-based antiseptic solutions for preoperative skin disinfection. We confirmed the hypothesis that preoperative cleaning of the skin before total hip or knee surgery with an alcohol-based antiseptic with additional OCT is more effective in reducing human skin flora than an alcohol-based antiseptic. alcohol with BAC.
Therefore, OCT reduced intracutaneous bacterial load and resulted in reduced detection of polymicrobial bacteria compared to antiseptic with BAC. To our knowledge, this is the first study to examine the effectiveness of solutions containing OCT compared to solutions containing BAC. Thus, besides the alcohol component, OCT appears to have an additional antimicrobial effect. OCT readily binds to negatively charged surfaces, such as microbial cell envelopes, eukaryotic cell membranes, and bacterial cell membrane components containing lipids, resulting in high antimicrobial activity22. Since OCT readily binds to negatively charged surfaces and is not absorbed percutaneously, at least some of the applied substance remains at the site of application, thus exerting a long-lasting antimicrobial effect (residual effect)22.23. Even with chronic wounds, OCT could be infection prevention24 due to a high effect on pathogenic microbiological load20. In addition, the antimicrobial effect of cell-bound OCT is much higher than that of chlorhexidine23. In vitro studies showed the high antimicrobial efficacy of OCT, which was 3-10 times higher than that of chlorhexidine25. In addition to the effectiveness of an antiseptic solution, the safety of the antiseptic for clinical use is important: octenidine is practically not absorbed by the skin, and toxic side effects or systemic interactions, when OCT is used on intact skin, should not be expected22.
The main source of PPI is the patient’s own normal skin flora9.10. According to previous studies on intraoperative contamination, surgical site infection and deep infections, staphylococci were the most isolated germs26,27,28. Contrary to the results of the current study, Dörfel et al. showed that in the shoulder after cleansing with povidone-iodine alcohol or chlorhexidine alcohol, the majority of bacteria on anaerobic plaques were cutibacterium acnes, while the majority of bacteria on aerobic plates were coagulase negative staphylococci (above all S. epidermidis, S. hominis, S. saprophyticus and S. lugdunensis), which accounted for more than 70%. S. aureus and M. luteus accounted for 6% of the aerobic flora29. The difference can be explained by the different sampling locations. At shoulder level, C. acnes infections are predominant30. The main tank of C. acnes is located deep in the skin (hair follicles and pilosebaceous glands)31.32. This could explain the different results of this study.
Data from Maurer et al.33 were also different: they found in the hip that only 12 out of 60 patients (20%) were colonized with C. avidum, while most patients were colonized with other bacteria, such as coagulase-negative staphylococci (47, 78.3%), C. acnes (11, 18.3%), Corynebacterium sp. (4, 6.7%), granular cutibacterium (2, 3.3%), Enterococci sp. (2, 3.3%), S. aureus (2, 3.3%).
We were able to detect a total of 34 positive bacteria in the BAC group and 25 positive bacteria in the OCT group from each 100 hip and knee samples. In contrast, Maurer et al.33 was able to detect bacteria in 51 of 60 samples (85%) from the hip. Concerning only the hip, we found 27 positive samples in the BAC group (39.1%) and 11 positive samples in the OCT group (16.7%). This can be explained by the fact that in the aforementioned study by Maurer et al. disinfection was performed with povidone iodine/alcohol. However, they demonstrated that standard povidone iodine/alcohol skin antisepsis combined with antibiotic prophylaxis incompletely eliminated Cutibacterium avidum of the groin at the time of the surgical skin incision. Factors such as number of cultures taken, timing, site of sampling, and sensitivity of culture methods may also contribute to the variation in reported contamination.
Mastrocola et al.34 confirmed in a meta-analysis of 8 studies that surgical skin prep with chlorhexidine alcohol is more effective than povidone iodine in reducing bacterial counts on human skin. On the other hand, according to Dörfel et al.29 Povidone-iodine alcohol either reduced aerobic flora better or more significantly reduced anaerobic flora in the shoulder after surgical skin preparation compared to chlorhexidine alcohol. Here, unlike our method, only the superficial layer of skin was tested using a standardized cup-scrub technique35. Numerically, as expected, there were more detections of bacteria in the skin than in the subcutaneous. Nevertheless, our study showed a significant difference in the detection of subcutaneous germs between OCT and BAC. A possible explanation for this finding is the continued activity of the various antiseptics used after skin separation, since no inactivating substances were used after skin removal.
Another difference between clinical studies is observed in the perioperative prophylaxis with antibiotics: in the present study (patients with arthroplasty), we systematically used perioperative antibiotics, whereas Dörfel et al.29 did not report such a procedure (shoulder surgery patients). Mastrocola et al.34.36 concluded that surgical skin preparation should be optimized to minimize normal skin flora, but other strategies, such as shortening the duration of surgery and the type of systemic antibiotic prophylaxis, should be considered to reduce the rate. surgical site infections.
Our study is not without limits, in particular its retrospective estimate concerning the comparison of the two antiseptics. First, the study was neither blinded nor randomized. Second, possible contamination during sample processing cannot be excluded despite sterile procedures. Third, bacterial skin load was used as an endpoint to compare the efficacy of the two antiseptics instead of periprosthetic infections. Further prospective follow-up studies comparing the two solutions should focus on the clinical endpoint “infection” and could compare the bacterial detection of infection with the bacteria detected in this study. From this, additional preoperative prophylaxis and additional knowledge can be derived. In addition, another limitation is that the tested antiseptics were not used in the same period. However, the surgery was performed the same way, there was no change in personnel or change in perioperative standards. Finally, we could not draw any conclusions on the residual effect of the two antiseptics since the tissue samples were only taken at one point in time. However, the residual effect after initial disinfection was not the focus of this study. In addition, skin removal after more than 2 h is not applicable since the average duration of hip and knee arthroplasty is less than 1-1.5 h.