TY - JOUR
AU - CTBS, Jeannie Callum, MD, FRCPC,
AB - Abstract The objective of this study was to review the incidence of skin allograft discard and bacterial contamination due to donor bioburden at the Ontario Professional Firefighters Skin Bank over a 14-year period. We sought to determine whether modifications to our prerecovery donor preparation process have been effective in reducing skin bioburden and identify other potential risk factors of allograft contamination. A retrospective review of all skin donors (n = 259) processed from 2002 to 2015 was performed. Multivariate logistic regression was used to determine whether donor-related factors and procurement-related factors were significantly associated with microbial contamination predisinfection and discard secondary to contamination. Eighty-one donor recoveries were discarded (81/259; 31%) or 694 grafts (694/2636; 26%), with bacterial contamination being the most common reason for discard (29/81; 36%) followed by positive viral serology (21/81; 26%) primarily for hepatitis B core antibodies. Bacterial contamination predisinfection was detected in 46% of donors (49% of grafts). Analysis of risk factors showed that only donor preparation using a 70% alcohol spray significantly reduced odds of both bacterial contamination predisinfection (P < .0001) and discard secondary to bacterial contamination (P = .0233). Our results suggest that selective screening of donors to reduce risk of microbial contamination is unlikely to alter the rate of allograft contamination. However, use of a 70% alcohol spray during donor preparation may minimize bacterial contamination and subsequent bacterial-related discards. Given that detailed guidelines for donor preparation do not exist, use of an alcohol spray may be of value for tissue banks experiencing allograft loss due to bacterial contamination. For deep burns, autologous skin grafting is the treatment of choice. However, this is often not immediately possible when patients with extensive burns do not have sufficient uninjured skin to provide autologous wound coverage. In this scenario, human skin allografts are the best alternative for temporary wound coverage as although they do not have intrinsic antimicrobial properties, they do diminish bacterial proliferation, promote pain relief, and significantly reduce both healing time and length of stay by up to 50% compared with use of topical antimicrobials.1,–4 Availability of cadaveric skin is often limited by the need to discard skin allografts due to contamination by pathogenic organisms and by a lack of suitable donors. In the Province of Ontario, Canada, it is estimated that 100 donations are required each year to meet demand for burn patients; however, the rate of donation in Ontario meets only half of this demand.5 It is essential that tissue banks ensure that allografts are safe for transplant, without severely restricting their availability. Skin allograft contamination is a common reason for discarding allografts, although cases of infectious transmission from allografting are rare.6 In the literature, rates of skin allograft contamination immediately following recovery range from 15-70%.1,6,–13 Published reports of tissue bank activity generally focus on post recovery disinfection and microbial sampling techniques; however, it is important that the surgical preparation of the donor is also included as a key component of skin bioburden reduction process. Studies report use of a variety of decontamination agents including povidone-iodine soap, chlorhexidine with 70% isopropanol solution, or betadine scrub.7,–13 In attempts to minimize graft loss, our tissue bank sequentially modified the use of these decontamination agents based on these reports and advice received from other tissue banks as there were no data to support one strategy over another. Nonetheless, the relative effectiveness of these donor preparation procedures has not been formally investigated in over two decades.14 The Ontario Professional Firefighters Skin Bank (OPFSB), located at Sunnybrook Health Sciences Centre in Toronto, ON, is the site of Ontario's largest burn unit and is focused entirely on providing split thickness skin for the treatment of patients with severe burns. The OPFSB must meet not only hospital and provincial needs for skin but must also maintain a reserve inventory as a contingency measure should there be a large-scale catastrophic event. The OPFSB is part of the hospital's American Associated Blood Bank accredited blood bank and is regulated by Health Canada and hence compliant with the Canadian Standards Association Cells, Tissues, and Organs Standards (CSA-Z900.1–12; CSA-Z900.2.2–12). There are currently six individuals who have completed their Certified Tissue Bank Specialist training with the American Association Tissue Banks employed in the tissue bank. The objective of this study was to review our activity over the past 14 years (2002–2015) focusing on reasons for skin allograft discard and incidence of bacterial contamination. We sought to determine whether modifications to our prerecovery donor preparation process over the study period have been effective in reducing skin bioburden and identify other potential procurement-related/external or donor-specific risk factors of allograft contamination. Our intention is to use this information to improve our current donor selection and/or processing protocol and reduce our overall donor loss rate. METHODS A retrospective review of all skin donors processed in the OPFSB from January 2002 to December 2015 was performed. Data collected included age, sex, weight, height, cause of death, organ donation, procurement date and site, operating team, time between death and start of procurement; time between death and cryopreservation, recovered skin area, as well as serological and microbiological data. Procurement of Skin Allografts Procurement of skin allografts begins within 24 hours of death if the donor is refrigerated within 12 hours post mortem. If the donor is not refrigerated, procurement begins within 15 hours post mortem. Allograft skin is recovered using an electric dermatome from the posterior back and legs following organ and eye recovery (where applicable). Bone, tendon, and heart valve recoveries occur thereafter. Donor scrub preparation is performed before skin recovery to reduce the degree of microbial contamination. During the study period, the donor scrub preparation procedure underwent both minor and major changes in the OPFSB as outlined in Table 1 in attempts to further mitigate bacterial contamination based on published reports and expert advice from other tissue banks. Before 2006, scrub preparation occurred only under aseptic conditions in the operating room. After 2006, an initial scrub under nonsterile conditions was added before the sterile scrub. During the nonsterile scrub, the donor is first placed in the prone position. After hair removal, two successive washes are done, both with chlorhexidine solution. The feet are only washed once then covered with sterile gloves before the second wash. The sterile donor scrub preparation then occurs under aseptic conditions adhering to Operating Room Nurses Association of Canada aseptic technique. Next, two 500 ml bottles of betadine are applied to the back, legs, inner thigh, and buttocks and after a 3-minute waiting period, the body is washed with two 450 ml bottles of chlorhexidine solution, omitting the buttocks. After all scrub steps are complete, the body is then draped with sterile linens leaving only the area of skin to be excised exposed. Adhesive towels are placed around the head/back and shoulders of the donor and an occlusive dressing is placed over the buttocks. Any area with skin abrasions is dressed outside the surgical field. After 2011, a 70% alcohol spray was added after sterile draping. The donor is left to air dry after the spray before application of sterile mineral oil for lubrication. Skin allografts 0.012 to 0.018 in are then removed by an electric dermatome. Immediately after removal, the grafts are placed in sterile jars in Tis-u-Sol solution and are transported to the OPFSB on wet ice. Temperature is maintained between above freezing (0°C) −10°C during transport and on receipt at the OPFSB the allografts are stored in a refrigerator at 1 to 6°C until processing begins. No other substantial changes were made to the recovery process during the time period other than to the donor sterile preparation and a gradual transition from a physician-based team to a technician-based team. Table 1. Comparison of the donor preparation process during the study period View Large Table 1. Comparison of the donor preparation process during the study period View Large Processing of Skin Allografts Processing is initiated within 96 hours of retrieval and is done under aseptic conditions in a biosafety cabinet in a bacteriological and climate-controlled environment. Allografts are removed from the transport solution and rinsed in Lactated Ringer's. Each allograft is inspected for quality and trimmed and dissected appropriately for cryopreservation. At this time a small piece is removed for culture. Once trimmed, grafts are placed in antibiotic solution containing 500 mg/vial vancomycin and 40 mg/ml (2 ml vial) tobramycin in RPMI 1640 culture media for 22 to 36 hours at 1 to 10°C (before 2014, gentamicin was used in place of tobramycin, with the change instigated by a shortage of gentamicin). No antifungal agents are included in the antibiotic cocktail. After disinfection, allografts are rinsed in Lactated Ringer's and packaged separately in a sterile pouch with a cryoprotectant solution of 10% dimethyl sulfoxide in X-vivo 10 for cryopreservation. Skin is cryopreserved using a Planer Kryo 10/16 Control rate freezer and stored below −40°C until the grafts are released or discarded. Skin is stored for a maximum of 5 years. Testing for Transmissible Diseases Infection with transmissible disease is assessed by serological testing of the donor for hepatitis B surface antigen (HBsAg), hepatitis B core antibody, hepatitis C antibody, human immunodeficiency virus (HIV) I & II antibody, human T lymphocyte virus (HTLV) I & II antibody, syphilis, nucleic acid test for hepatitis B, hepatitis C, HIV, and West Nile Virus. A positive test result leads to discard of the donor allografts (a positive test result means the test specimen is determined to be “reactive,” “repeatedly reactive,” or “positive” according to the testing algorithms recommended by the test kit manufacturer). Confirmatory testing for HIV is not performed for donors repeatedly reactive for HIV antibodies by initial testing. Evaluation of Microbial Contamination Microbiological sampling is done during processing (pre-Ab) and after disinfection (post-Ab). Small samples (0.5 × 0.5 cm) are cut from each allograft. These are pooled together, minced, and divided into two. Each division is suspended in 10 ml Lactate Ringer's. One sample is inoculated into tryptic soy broth incubated at ambient temperature for aerobic bacteria and rapidly growing yeast, and the other is inoculated into thioglycolate broth incubated at 35°C for recovery of anaerobic bacteria. Both broths are examined daily for turbidity for a total of 14 days. If turbidity becomes apparent, the broths are subcultured to blood agar and Brucella agar plates incubated at 35°C for 48 hours. The blood agar plates are incubated in CO2 and the Brucella agar plates are incubated anaerobically. If there is no broth turbidity evident on day 14, the broths are subcultured as described above. These procedures did not change during the study period. Any bacterial growth on the pre- or post-antibiotic cultures was considered for the study as “positive” irrespective of the organisms found. Release of Skin Allografts From Quarantine The donor chart is reviewed (consent form, medical/social history, tissue donor assessment, hemodilution relevant medical and chart notes, autopsy/coroner's report, serological and microbial test results) to determine if the allografts are suitable for release from quarantine. Acceptable bacterial culture results include 1) no growth on pre- and post-Ab cultures and 2) growth of less than or equal to two species of nonspore-forming bacteria on pre-Ab cultures but no growth on the post-Ab cultures (growth of greater than or equal to three species of bacteria on pre-Ab but not post-Ab cultures is left to the discretion of the medical director). Unacceptable bacterial culture results leading to tissue discard include 1) growth of spore-forming bacteria (Bacillus and Clostridium species) on pre-Ab cultures; 2) growth on both the pre- and post-Ab cultures; and 3) no growth on pre-Ab cultures but growth on post-Ab cultures. Statistical Analysis All analyses were conducted using Statistical Analysis Software (SAS 9.3; SAS Institute Inc.; Cary, NC). Categorical variables were summarized as frequencies and percentages; continuous variables as means with SD or as medians with interquartile ranges if data were skewed. We analyzed seven donor-related factors for their association with microbial contamination pre-Ab and with discard secondary to microbial contamination: sex, age, BMI, history of tobacco use, history of drug use, intensive care unit (ICU) admission, organ donation and cause of death; and seven factors relating to external procurement conditions; number of grafts procured, number of team members, donor preparation using the alcohol spray, time from death to procurement, disinfection time, and time from death to cryopreservation. Associations were first determined using a univariate analysis. Factors identified as significant in univariate analysis were included in a multivariate analysis using a logistic regression model. For the multivariate analysis, age, number of grafts and number of team members were treated as continuous outcomes. Due to multicollinearity, use of the nonsterile donor preparation could not be included as a variable in the multivariate regression and thus was not formally analyzed for association with pre-Ab contamination and discard secondary to contamination analysis. A P value less than .05 was considered significant. RESULTS Donor and Allograft Characteristics During the study period, 2636 allografts were procured from 259 cadaveric donors. The number of donors increased consistently during the study period from five donors in 2002 to 80 donors in 2015 (data unavailable for 14 donors in 2015 due to incomplete charts at the time of data collection—e.g., autopsy report pending). Characteristics of the donors are displayed in Table 2. Skin procurement was performed at 48 different hospitals (mix of academic and nonacademic hospitals in the Province of Ontario) by 72 different staff members arranged in teams ranging from two to four individuals (median: 3). Team members were inconsistent and most staff members procured skin from under 10% of the total donors. The variability in the team members was due to the length of the study period (many of the team members were physicians in training and a third circulating person was provided from a large pool of technicians provided by Trillium Gift of Life, our local Organ Procurement Organization and nurses from the operating room at the local facility who provided circulating nurse functions). The total surface area of skin procured was 399,285 cm2 with a median surface area per donor of 1626 cm2. The median number of allografts procured per donor was 11 (interquartile range: 9–13). During the study period, there were no reports of bacterial or viral transmission from all transplanted skin allografts. Table 2. Donor characteristics View Large Table 2. Donor characteristics View Large Discarded Skin Allografts A total of 81 donor recoveries were discarded (81/259; 31%) or 694 grafts (694/2636; 26%), with bacterial contamination being the most common reason for discard (29/81; 36%; 337/2636; 13% of grafts) followed by positive viral serology (21/81; 26%). Other reasons for discard included medical/social history (12/81; 15%), positive bronchoalveolar lavage, blood or respiratory culture (5/81; 7%); unsuitable physical allograft characteristics (4/81; 5%); missing information (4/81; 5%); autopsy findings (4/81; 5%); and processing or transport error (2/81; 2%). Transmissible Disease Testing Transmissible disease testing was performed for 245 donors (245/259; 95%). Transmissible disease testing was cancelled in donors ineligible for other reasons. Nine percent (21/245) of donors tested positive and thus were discarded (171/2542; 7% of grafts). Four of the donors discarded tested positive for multiple viruses. The majority (11/21; 52%) of the discards were for hepatitis B (hepatitis B core antibody positive, 8/11; HBsAg, 2/11; both, 1/11). The remaining were for HTLV antibody I and II (8/21; 38%); HIV antibody I and II (1/21; 5%); positive syphilis screening (1/21; 5%); hepatitis C Virus (1/21); and positive nucleic acid test for West Nile Virus (1/21; 5%). Most of the discards secondary to positive viral serology occurred toward the end of the study period, in 2015 (13/21; 62% of serology-related discards occurred in 2015; Figure 1). Figure 1. View largeDownload slide Loss of skin allografts due to positive transmissible disease testing. Each bar indicates the total number of donors per year who underwent transmissible disease testing, with the shaded portion indicating the number of donors discarded due to positive viral serology. The proportion of donors each year discarded due to positive viral serology is indicated by the percentage value above each bar. Note that there were no donors in 2009. Figure 1. View largeDownload slide Loss of skin allografts due to positive transmissible disease testing. Each bar indicates the total number of donors per year who underwent transmissible disease testing, with the shaded portion indicating the number of donors discarded due to positive viral serology. The proportion of donors each year discarded due to positive viral serology is indicated by the percentage value above each bar. Note that there were no donors in 2009. Microbiological Results Microbial contamination before disinfection (i.e., positive pre-Ab cultures) was detected in 46% of donors who had microbial testing performed (110/238 donors, 1270/2582 grafts; 49%). Microbial testing was cancelled in donors ineligible for other reasons. No fungal contamination was detected. The most common bacterial species isolated from the donors were normal skin flora of low pathogenicity (85/110; 77%), namely coagulase-negative Staphylococcus (75/110; 68%; Table 3). Multiple organisms were isolated from 30 donors (30/110; 27%). Table 3. Isolated bacteria from 238 donors who underwent microbial testing View Large Table 3. Isolated bacteria from 238 donors who underwent microbial testing View Large The majority of contamination-related discards were due to the pathogenicity of the bacterial species isolated from the pre-Ab bacterial cultures (18/29; 62%); 16 due to spore-forming bacilli (9/16 Bacillus and 7/16 Clostridium); one due to Enterococcus species and one due to contamination with over three species of bacteria. Allografts from eight donors (8/29; 28%) were discarded due to persistent bacterial growth after disinfection and three donors (3/29; 10%) due to positive post-Ab cultures only (Table 3). The year-by-year proportions of donors with bacterial contamination predisinfection were not consistent during the study period (Figure 2). After the addition of the nonsterile donor preparation in 2006, there was not a noticeable change in proportion of donors with bacterial contamination predisinfection or in the proportion of donors discarded due to bacterial contamination. Each year, after the addition of the alcohol spray in 2010, there was a sustained decrease in the proportion of donors (who underwent microbial testing) with bacterial contamination predisinfection (2002–2009; 89% [54/61] of donors vs 2010–2015: 34% [60/177]) and in the proportion of donors (who underwent microbial testing) that were discarded due to bacterial contamination (2002–2009: 21% [13/61] of donors vs 2010–2015: 9% [16/177]). Figure 2. View largeDownload slide Incidence of bacterial contamination and discard of contaminated skin allografts during the study period. A. Each bar indicates the total number of donors per year who underwent microbial testing, with the shaded portion indicating the number of donors with positive preantibiotic bacterial cultures. The proportion of donors each year with positive preantibiotic cultures is indicated by the percentage value above each bar. B. Each bar indicates the total number of donors per year who underwent microbial testing, with the shaded portion indicating the number of donors discarded due to preantibiotic bacterial contamination. The proportion of donors per year discarded due to preantibiotic bacterial contamination is indicated by the percentage value above each bar. Note that there were no donors in 2009. Figure 2. View largeDownload slide Incidence of bacterial contamination and discard of contaminated skin allografts during the study period. A. Each bar indicates the total number of donors per year who underwent microbial testing, with the shaded portion indicating the number of donors with positive preantibiotic bacterial cultures. The proportion of donors each year with positive preantibiotic cultures is indicated by the percentage value above each bar. B. Each bar indicates the total number of donors per year who underwent microbial testing, with the shaded portion indicating the number of donors discarded due to preantibiotic bacterial contamination. The proportion of donors per year discarded due to preantibiotic bacterial contamination is indicated by the percentage value above each bar. Note that there were no donors in 2009. Predisposing Factors In the univariate analysis for association with bacterial contamination predisinfection, donor age, cause of death, ICU admission, organ donation, number of team members, time from death to recovery, and donor preparation method were found to be significant. On inclusion of these variables in a multivariate logistic regression, only donor preparation without use of the alcohol spray was significantly associated with bacterial contamination predisinfection (P < .0001). The odds of having positive preantibiotic cultures was 15.1 times higher for donors prepared without the alcohol spray compared with donors prepared using the alcohol spray (Table 4). Table 4. Multivariable logistic regression analysis for bacterial contamination predisinfection with antibiotics (n = 238) View Large Table 4. Multivariable logistic regression analysis for bacterial contamination predisinfection with antibiotics (n = 238) View Large In the univariate analysis for association with discards secondary to bacterial contamination, only the number of grafts procured and donor preparation method were found to be significant. On inclusion of these variables in a multivariate logistic regression, only donor preparation without use of the alcohol spray was significantly associated with discard due to bacterial contamination (P = .0233). The odds of allograft discard due to bacterial contamination were 2.7 times higher for donors not prepared using the 70% alcohol spray. DISCUSSION During the past 14 years, the most common reason for discard of skin allografts at the OPFSB was bacterial contamination (29/81; 36%). However, we found that the addition of a 70% alcohol spray to our donor preparation process significantly reduced odds of contamination immediately post recovery (89% of donors contaminated pre-Ab treatment vs 34%) and the odds of discards secondary to bacterial contamination (21% of donors discarded due to positive cultures vs 9%). The number of skin donors processed by the OPFSB increased markedly during the study period from five donors in 2002 to 80 donors in 2015. This finding is likely a result of “Routine Notification and Request” implemented by the Trillium Gift of Life Network in 2006, which required Ontario hospitals that provide neurosurgery or trauma services to report all deaths or patients at high risk for imminent death in the ICU or emergency department to Trillium Gift of Life Network.15 In 2013, Routine Notification and Request was broadened to require reporting from all wards. Allografts from 21 donors (9%) were discarded because of positive viral serology, which is at the higher end of the range of serology-related discards reported in the literature, of 0.6 to 10%.9,12,13,16 This was the reason for tissue loss for 26% of discarded donor tissue. Most of the discards secondary to serology occurred in 2015, specifically for anti-HBc and HTLV Abs. Both of these tests are historically known to have high false reactivity rates given their high sensitivity and when used to screen individuals for blood donation have led to the deferral of otherwise qualified donors.17,18 For example, Katz et al17 found that of 1324 anti-HBc repeat reactive deferred blood donors, 37% were not only nonreactive on a more specific anti-HBc assay, but did not react with a licensed HBsAg test and licensed HBV DNA assay. We also have hypothesized that some of the false-positive test results may be due to poor sample integrity (eg, hemolysis) and are working with our recovery personnel to minimize hemolysis by the use of large bore needles and separate temperature controlled transport boxes for samples. In the past 2 years, we transitioned to primarily technician-based teams and have raised the possibility of poor sample draw technique leading to hemolysis and interference with the assay. To reduce donor loss from false-reactive tests, including the forementioned, Canadian Blood Services introduced a donor re-entry program in 2014, whereby previously deferred donors with false-positive HIV, hepatitis B Virus, or hepatitis C Virus results can resume donating blood.19 It is possible that many of our serology-related discards were attributable to false-positive test results. Use of more lenient guidelines may also explain lower rates of serology-related discard in the literature. For example, under current French guidelines, tissue donors with anti-Hbc Abs in the absence of HBsAg and HBV nucleic acids are accepted.9 Use of these criteria at the OPFSB would have resulted in the acceptance of one third of the donors discarded due to positive viral serology. We found a bacterial contamination rate of 46% of donors (49% of allografts) immediately after recovery. In the literature, predisinfection microbial contamination rates range from 15 to 70% of allografts procured.6,–11,13,20,–22 Discrepancies with other studies may be explained by differences in donor preparation before recovery. Numerous donor preparation techniques have been reported and team compliance with these techniques has never been formally audited, which makes assessing their relative efficacies in reducing bioburden a challenge. Current guidelines for donor preparation by the American Association of Tissue Banks recommend that areas of excision be cleansed with antimicrobial agents, but do not provide specific product recommendations.23 The only formal investigation of donor preparation for skin allograft recovery was performed in 1991 by May et al14 who found that the addition of 4% chlorhexidine gluconate to a povidone iodine/betadine/isopropanol preparation reduced body surface contamination from 13 to 5.6%. Use of chlorhexidine is also recommended for preoperative skin antisepsis. Two large randomized control trials have both suggested chlorhexidine in 70% alcohol is more effective than povidone-iodine for the prevention of surgical site infections.24,25 We found that the addition of a 70% alcohol spray to the end of our donor preparation, which includes abundant washing with chlorhexidine, significantly reduced odds of bacterial contamination predisinfection by 15 times and bacterial-related discards by 2.7 times, all while accounting for potential donor- and procurement-related confounding factors. Given that detailed guidelines for donor preparation do not exist, our technique may be of use for tissue banks experiencing allograft skin loss due to bacterial contamination. Our use of vancomycin and tobramycin/gentamycin for disinfection of skin allografts was effective in eliminating bacterial contamination. Before antibiotic treatment, 46% of donors were culture positive whereas after treatment only 3% remained positive. There is significant heterogeneity and lack of comparative analysis in the literature regarding antibiotic disinfection of skin allografts, which prevents identification of an optimal method. At the OPFSB, isolation of bacteria following antibiotic treatment results in automatic discard of donor tissue, in addition to isolation of spore-forming bacteria from pre- or post-antibiotic cultures (20% of discards in our study). However, this protocol is not ubiquitous in the literature, which may explain variability in allograft discard between tissue banks. For example, Neely et al6 suggested that all of their allografts could be released for transplantation, despite 6.8% of allografts having a positive post antimicrobial culture result. Also at the OPFSB, pre- and post-antibiotic samples from each allograft are grouped by donor for microbial testing. Therefore, it is assumed that all allografts procured from one donor are equally contaminated and thus allografts are discarded on a donor basis and not individually. It was suggested by Gaucher et al that separate procurement of 8 to 10 zones from each donor and only discard of contaminated zones effectively decreases the surface area rejected given that authors found each zone had significantly different rate of contamination.9 We found that donor-specific factors did not influence the positivity rate of skin allografts. This finding suggests that selective screening of donors to reduce risk of microbial contamination is unlikely to reduce allograft loss and fortunately does not suggest further restrictions be placed on the already limited skin donor pool. Contrary to some others, we found that external/procurement-related factors, such as the number of team members or grafts recovered, were not significantly associated with contamination (outside of use of the alcohol spray) which further supports the efficacy of our donor preparation procedure.7,8,20 Many of these variables have been assessed previously for their association with bacterial contamination of both skin and musculoskeletal allografts; however, the variables found to be statistically significant are not consistent.7,–10,20,–22 These differences may be a result of variability in tissue bank practice or may be attributable to the method of data analysis chosen by the authors such as testing at the graft level vs donor level; subdividing microorganisms by pathogenicity; and use of univariate regression. As cautioned by Lannau et al,22 examining variables at the graft level can lead to an artificial rise of statistical power and use of only univariate regression may mask confounding factors. To cope with these effects, we chose to categorize all variables at the donor level and used multivariate regression to determine associations. In conclusion, bacterial contamination was found to be the main cause of skin allograft discard at the OPFSB during the past 14 years. Donor-related factors were not found to significantly influence bacterial contamination and unfortunately may not be of use to streamline the donor selection process. In addition, procurement-related, external factors were not found to influence risk of contamination with the exception of prerecovery donor preparation. The addition of a 70% alcohol spray to our donor preparation procedure was found to significantly reduce odds of both bacterial contamination predisinfection and discard secondary to bacterial contamination. Bacterial contamination is repeatedly cited as the most common reason for skin allograft discard and there is marked variability in both the prerecovery donor preparation and postrecovery disinfection processes in the literature, which are both important factors in reducing skin bioburden. Therefore, it is important that tissue banks continue to share their experiences and procedures to improve consistency in practice and ensure that preventable skin allograft losses, such as those due to bacterial contamination are minimized. Evidently, well-designed randomized trials are needed to formally compare different disinfection processes to determine the strategy that yields the greatest decrease in bacterial load. REFERENCES 1. van Baare J Ligtvoet EE Middelkoop E. Microbiological evaluation of glycerolized cadaveric donor skin. Transplantation  1998; 65: 966– 70. Google Scholar CrossRef Search ADS PubMed  2. Greenleaf G Cooper ML Hansbrough JF. Microbial contamination in allografted wound beds in patients with burns. J Burn Care Rehabil  1991; 12: 442– 5. Google Scholar CrossRef Search ADS PubMed  3. Hermans MHE. Porcine xenografts vs. (cryopreserved) allografts in the management of partial thickness burns: Is there a clinical difference?. Burns  2014; 40: 408– 15. Google Scholar CrossRef Search ADS PubMed  4. Naoum JJ Roehl KR Wolf SE Herndon DN. The use of homograft compared to topical antimicrobial therapy in the treatment of second-degree burns of more than 40% total body surface area. Burns  2004; 30: 548– 51. Google Scholar CrossRef Search ADS PubMed  5. The GJC Consulting Group Tissue Banking in the Province of Ontario: Review and Analysis. (A Report Commissioned by Trillium Gift of Life Network) . 2014: 1– 169; available from https://www.giftoflife.on.ca/resources/pdf/Tissue_Banking_in_Ontario_Review___Analysis_Report.pdf; accessed 13 July 2016. 6. Neely AN Plessinger RT Stamper B Kagan RJ. 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Terzaghi C Longo A Legnani C Bernasconi DP Faré M. Incidence of bacterial contamination and predisposing factors during bone and tendon allograft procurement. Cell Tissue Bank  2015; 16: 151– 7. Google Scholar CrossRef Search ADS PubMed  21. Schubert T Bigaré E Van Isacker T Gigi J Delloye C Cornu O. Analysis of predisposing factors for contamination of bone and tendon allografts. Cell Tissue Bank  2012; 13: 421– 9. Google Scholar CrossRef Search ADS PubMed  22. Lannau B Van Geyt C Van Maele G Beele H. Analysis of potential factors affecting microbiological cultures in tissue donors during procurement. Cell Tissue Bank  2015; 16: 65– 71. Google Scholar CrossRef Search ADS PubMed  23. American Association of Tissue Banks Changes to AATB Standards for Tissue Banking: Section D - Acquisirion of Tissue: Consent, Donor Screening, and Tissue Recovery and Collection . 2007: 5; available from http://www.aatb.org/files/071007changesectiond.pdf; accessed 13 July 2016. 24. 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TI - A 14-Year Audit and Analysis of Human Skin Allograft Discards
JO - Journal of Burn Care & Research
DO - 10.1097/BCR.0000000000000485
DA - 2017-09-01
UR - https://www.deepdyve.com/lp/oxford-university-press/a-14-year-audit-and-analysis-of-human-skin-allograft-discards-cY6uI8dkWc
SP - e786
EP - e795
VL - 38
IS - 5
DP - DeepDyve
ER -