Evaluation of decontamination process of heart valve and artery tissues in European Homograft Bank (EHB): a retrospective study of 1,055 cases

Abstract

To evaluate the efficiency of decontamination practice in European Homograft Bank (EHB), the data of the cardiovascular tissues received during recent 2 years were retrospectively analysed in this study. After initial assessment, the tissues were incubated in a 3-antibiotics' cocktail at 4°C for 20-48 h. The states of contamination were evaluated before and after incubation with the focus on the differences in donor type, tissue type, germ type and incubation time. Amongst 1,055 eligible tissues, 77.2% were hearts and 22.8% were arteries. 82.2% of the tissues were retrieved from the multi-organ donors (MOD), 15.4% from the recipients of heart transplantation (RHT) and 2.4% from the non-heart beating donors (NHBD). The initial contamination rate was 27.4% with a significantly higher incidence in arteries. The RHT tissues had the lowest contamination rate comparing to that of MOD and NHBD. Staphylococcus species was the major source of contamination. After antibiotic incubation, 76.8% of the contaminated tissues were disinfected, which was significantly higher for the hearts than the arteries. The RHT tissues had the highest decontamination rate than that of MOD and NHBD tissues. Propionibacterium acnes was detected in 48.1% of the remaining contaminated cases. The average incubation time of the Propionibacterium-positive tissues was significantly shorter than that of decontaminated tissues. In conclusion, the current decontamination protocol of EHB is sufficient for most of the initially contaminated bacteria, whereas it is inadequate for Propionibacterium acnes. This may be related to the slow-growing nature of this bacterium and thereby the relative shorter antibiotic incubation time.

Evaluation of allograft contamination and decontamination at the Treviso Tissue Bank Foundation: A retrospective study of 11,129 tissues

“…This caused a major increase in positivity for all types of strains, including gram-negative and sporogenous bacteriae. Our overall decontamination rate in CVT after the first decontamination is comparable to that of previous reports [14], although our sample was mainly comprised of NHBD. There might be several explanations for the residual percentage of contaminated tissues at the end of the process.…”

“…In contrast, Fan et al reported that an AB cocktail of lincomycin, polymyxin B and vancomycin reduced the bacterial contamination rate by 76.8% at 4°C for at least 20h [14]. However, two-step decontamination procedure was effective even at low temperatures in most tissues, including CVT, suggesting that the initial bio-burden was probably very low.…”

A Case of Misidentification ofAspergillus versicolorComplex asScopulariopsisSpecies Isolated from a Homograft

“…The transmission of infection from tissue to recipients has been documented on a number of occasions, despite the fact that infection following the implantation of homografts is rarely reported [4]. To prevent the transmission of microbes to recipients, the microbiological evaluation and decontamination of tissues is commonly practiced in tissue banks around the world [5]. Although special guidelines…”

Determination of Residual Antibiotics in Cryopreserved Heart Valve Allografts

“…2 of the 3 antibiotics of the Tissue Establishments have adopted the less toxic antibiotics and accepted a decrease in the yield of allografts due to insufficient decontamination. Every year, as many as 5-10% of all processed allografts have been discarded for insufficient decontamination in our Tissue Establishment [2]. However, due to the low toxicity of our antibiotics cocktail, the quality of the heart valve and vascular allografts was high and the rate of explantation of these allografts was relatively low [11,21].…”

“…Exposure to low concentrations of different antibiotics during the 20-48 h before cryopreservation reduces the contamination rate to about 5-10% [2,3]. Different Tissue Establishments worldwide, responsible for cardiovascular allograft decontamination, have adopted different cocktails of antibiotics, under different temperature conditions and for varying duration [4][5][6].…”