The Effects of Surgical Antiseptics and Time Delays on RNA Isolated From Human and Rodent Peripheral Nerves.

Peripheral Nerve Injury (PNI) is common following blunt or penetrating trauma with an estimated prevalence of 2% among the trauma population. The resulting economic and societal impacts are significant. Nerve regeneration is a key biological process in those recovering from neural trauma. Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) and RNA sequencing (RNA seq) are investigative methods that are often deployed by researchers to characterize the cellular and molecular mechanisms that underpin this process. However, the ethical and practical challenges associated with studying human nerve injury have meant that studies of nerve injury have largely been limited to rodent models of renervation. In some circumstances it is possible to liberate human nerve tissue for study, for example during reconstructive nerve repair. This complex surgical environment affords numerous challenges for optimizing the yield of RNA in sufficient quantity and quality for downstream RT-qPCR and/or RNA seq applications. This study characterized the effect of: (1) Time delays between surgical liberation and cryopreservation and (2) contact with antiseptic surgical reagents, on the quantity and quality of RNA isolated from human and rodent nerve samples. It was found that time delays of greater than 3 min between surgical liberation and cryopreservation of human nerve samples significantly decreased RNA concentrations to be sub-optimal for downstream RT-qPCR/RNA seq applications (<5 ng/µl). Minimizing the exposure of human nerve samples to antiseptic surgical reagents significantly increased yield of RNA isolated from samples. The detrimental effect of antiseptic reagents on RNA yield was further confirmed in a rodent model where RNA yield was 8.3-fold lower compared to non-exposed samples. In summary, this study has shown that changes to the surgical tissue collection protocol can have significant effects on the yield of RNA isolated from nerve samples. This will enable the optimisation of protocols in future studies, facilitating characterisation of the cellular and molecular mechanisms that underpin the regenerative capacity of the human peripheral nervous system.

Prospective, randomised clinical trial of four different presurgical hand antiseptic techniques in equine surgery.

BACKGROUND: Currently, the World Health Organization recommends the use of alcohol-based hand rubs (ABR) for surgical hand preparation in human surgery. When disinfecting soaps are used, a rubbing technique causes less skin irritation than brush scrubbing. Based on a recent survey, most equine surgeons still use disinfecting soap. The efficacy of scrubbing vs. rubbing and the use of sole ABR compared with chlorhexidine (CHx)- based products has not been evaluated in the equine surgical setting. OBJECTIVES: To compare four surgical hand antisepsis techniques in equine surgery for reduction of aerobic bacterial counts from pre- to post-preparation (immediate efficacy) and at the end of surgery (sustained efficacy). STUDY DESIGN: Randomised, prospective clinical trial. METHODS: A 4% CHx-based product applied with either a scrub or rub technique, one sole ABR (ET; 80% ethanol) and one CHx/alcohol-combination (CHx/ET; 1% CHx and 61% ethanol) product both applied with a rub technique were evaluated. Samples were collected by glove juice technique and cultured on 3M™ Petrifilm plates and counted using a 3M™ Petrifilm plate reader. RESULTS: Immediate mean bacterial log10 colony forming unit (CFU) reduction was 2.4 for CHx-scrub, 2.8 for CHx-rub, 3.1 for CHx/ET and 2.1 for ET. CHx/ET resulted in significantly lower bacterial counts than CHx-scrub (P<0.005) and ET (P<0.001) while CHx-rub resulted in significantly lower counts than ET (P<0.001). At the end of surgery bacterial counts were the lowest for CHx-rub, significantly lower than CHx/ET (P<0.001) and ET (P<0.001). There was no difference between CHx-rub and -scrub techniques (P = 0.7). MAIN LIMITATIONS: Bacterial counts were used as the outcome measure rather than prevalence of surgical site infection, and the effect of hand preparation on skin health was not assessed. CONCLUSIONS: ABR did not decrease bacterial log10 CFU counts more effectively than CHx products. When using CHx soaps in the equine setting, hand-rub is as effective as a hand-scrub-technique.

Aseptic surgical preparation for upper eyelid blepharoplasty via full-face octenidine antiseptic without antibiotic medication shows effective prophylaxis against post-surgical wound infection.

Blepharoplasty is the third most common plastic surgical procedure in the USA. Due to the emergence of multiresistant bacteria, optimising the antiseptic procedure is crucial. Choice of antiseptics plays an important role as they may cause skin irritation and colouring of disinfected areas. In this study, the use of the aqueous antiseptic octenisept® (octenidine) was evaluated in the outcome of blepharoplasties: incidence of wound dehiscence; haematoma; and infection in correlation with gender, medication, smoking habits and time of year. This retrospective surveillance study included 352 patients (median age 58·3 years). Skin disinfection was performed thrice prior to blepharoplasty. Sutures were removed on day 6. None of the patients suffered from wound infection. The total rate of wound dehiscence was 6·3%, with a higher ratio among male patients. Smokers and patients on anticoagulant medication showed a significantly higher incidence of wound dehiscence. Throughout the year, rates of wound dehiscence were highest in summer. Aseptic surgical preparation for blepharoplasty via full-face scrub with octenisept® without oral antibiotic prophylaxis is well tolerated, with no report of wound infection, which may improve antibiotic stewardship as well as patient comfort. Elective upper eyelid blepharoplasty may ideally be performed in winter.

Comparative antimicrobial efficacy of alcohol-based hand rub and conventional surgical scrub in a medical center.

BACKGROUND: Hand hygiene is the cornerstone of aseptic techniques to reduce surgical site infection. Conventional surgical scrub is effective for disinfecting a surgeon's hands. However, the compliance of conventional scrub may be hindered by skin damage, allergy, and time. Alcohol-based hand rub has a satisfactory antimicrobial effect, but mostly in laboratory settings. Our aim was to compare a conventional surgical scrub with an alcohol-based hand rub to evaluate antimicrobial efficacy. METHODS: From June 1, 2010 to July 31, 2011, 128 healthcare workers were enrolled in the study. They used an alcohol-based hand rub or a conventional surgical scrub as preoperative hand antisepsis during their routine practice. Hand sampling for cultures were performed before and after operations. Positive culture plates were further processed for pathogen identification. RESULTS: The culture positive rate of the alcohol-based hand rub was 6.2% before operations and 10.8% after operations. Both rates were lower than the conventional surgical scrub [47.6% before operations (p < 0.001) and 25.4% after operations (p = 0.03)]. The most identified pathogens were Gram-positive with coagulase-negative staphylococci being the major pathogen. Multivariate analysis showed that prior hand condition (p = 0.21) and type of surgery such as cardiovascular surgery (p = 0.12) were less relevant, but the alcohol-based hand rub was a significant protective factor for positive hand cultures. CONCLUSION: The alcohol-based hand rub was more efficacious for surgical antisepsis and had sustained efficacy, compared to conventional surgical scrub. We suggest that alcohol-based hand rubs could be an alternative surgical antiseptic in the operative theater.