Antimicrobial efficacy of preoperative skin antisepsis and clonal relationship to postantiseptic skin-and-wound flora in patients undergoing clean orthopedic surgery

Abstract

Nosocomial surgical site infections (SSI) are still important complications in surgery. The underlying mechanisms are not fully understood. The aim of this study was to elucidate the possible role of skin flora surviving preoperative antisepsis as a possible cause of SSI. We conducted a two-phase prospective clinical trial in patients undergoing clean orthopedic surgery at a university trauma center in northern Germany. Quantitative swab samples were taken from pre- and postantiseptic skin and, additionally, from the wound base, wound margin, and the suture of 137 patients. Seventy-four patients during phase I and 63 during phase II were investigated. Microbial growth, species spectrum, and antibiotic susceptibility were analyzed. In phase two, the clonal relationship of strains was additionally analyzed. 18.0 % of the swab samples were positive for bacterial growth in the wound base, 24.5 % in the margin, and 27.3 % in the suture. Only 65.5 % of patients showed a 100 % reduction of the skin flora after antisepsis. The microbial spectrum in all postantiseptic samples was dominated by coagulase-negative staphylococci (CoNS). Clonally related staphylococci were detected in ten patients [nine CoNS, one methicillin-susceptible Staphylococcus aureus (MSSA)]. Six of ten patients were suspected of having transmitted identical clones from skin flora into the wound. Ethanol-based antisepsis results in unexpected high levels of skin flora, which can be transmitted into the wound during surgery causing yet unexplained SSI. Keeping with the concept of zero tolerance, further studies are needed in order to understand the origin of this flora to allow further reduction of SSI.

Povidone-iodine-alcohol is superior to chlorhexidine-alcohol in its antimicrobial efficacy on the anaerobic microbial flora in surgical skin preparation of the shoulder Region

“…This is consistent with ndings from an earlier study in which CNS were frequently detected in the surgical eld after 3 minutes of preoperative skin antisepsis with CHG-ALC (unpublished ndings). This is also consistent with data from another study [4] that showed growth of residual bacteria directly after skin antisepsis with 70% v/v isopropanol in 35% of operations in orthopedic surgery. Among the isolates recovered after antisepsis, 53% were identi ed as CNS, and clonally related strains were subsequently found in surgical wounds in 10% of operations [4].…”

“…This is also consistent with data from another study [4] that showed growth of residual bacteria directly after skin antisepsis with 70% v/v isopropanol in 35% of operations in orthopedic surgery. Among the isolates recovered after antisepsis, 53% were identi ed as CNS, and clonally related strains were subsequently found in surgical wounds in 10% of operations [4]. These data underscore the need for better protection against CNS in surgery by potent antisepsis.…”

“…The skin ora of patients is one of the most important factors in the pathogenesis of surgical site infections (SSI) [1][2][3][4]. Skin antisepsis constitutes an effective measure to reduce the numbers of microorganisms on skin.…”

Povidone-iodine-alcohol is superior to chlorhexidine-alcohol in its antimicrobial efficacy on the anaerobic microbial flora in surgical skin preparation of the shoulder region

“…In aerobic cultures, PVP-I-ALC was better than CHG-ALC only after 2.5 min contact time and immediate sampling ( Table 2), but not in any other of the tested parameters, including prolonged application time and sampling after 3 h. CNS which multiplies aerobically and to a lesser extend anaerobically, were not completely eliminated by CHG-ALC. This corresponds with findings that after 3 minutes of preoperative skin antisepsis with CHG-Alc always CNS were detected in smears in the surgical field before implantation of hip endoprostheses (unpublished) and also with data showing bacterial growth directly after skin antisepsis (propan-2-ol (70 % v/v) in 35% of operations in traumatology, whereof 53% were identified as CNS which finally caused wound contaminations in 10% of operations with clonally related strains [4]. These data underline the need for better protection against CNS in at least orthopaedic and trauma surgery by adequate potent antisepsis in order to better prevent up to now still unacceptable infection rates predominantly caused by CNS.…”

“…The skin flora of patients is one of the most important factors in the pathogenesis of surgical site infections (SSI) [1][2][3][4]. Skin antisepsis constitutes an effective measure to reduce the numbers of microorganisms on skin and has been included as a key measure to prevent SSIs in recent international guidelines and recommendations [5][6][7].…”