Risk factors associated with contamination of allograft valves in a tissue bank

Abstract

The contamination of the transport solution used in cardiovascular allografts can occur from different sources. Risk factors associated with positive microbiological test of transport solution have not been reported previously. This study aimed to determine the risk factor for contamination of transport solution used in the heart valve allografts stored in a Brazilian tissue bank. This retrospective study was conducted on all donors of cardiovascular allografts stored in a tissue bank from December 2008 to December 2017. Microbiological cultures for aerobic and anaerobic bacteria, fungi/yeasts were carried out in TS. Clinical variables were included. From 1001 transport solution, 52% were contaminated. A total of 770 microorganisms were identified, and Staphylococcus spp. was identified in 248 isolates (32.2%). Skin bacteria from skin microbiota were the most commonly identified microorganisms (Staphylococcus spp., Cutibacterium spp., Corynebacterium spp., and Bacillus spp.), occurring in 49.6%. The presence of a diagnosis of healthcare-associated infection was not associated with skin contamination (odds ratio [OR] 0.62 [0.41–0.94]; p = 0.014). Conditions like fever, use of antibiotics, and leukocytosis were less likely associated with contamination of transport solution. A longer warm ischemic time was associated with higher frequency of contamination. In the multivariable analysis, warm ischemic time was independently associated with contamination, and antibiotic therapy was a factor that decreased the rate of contamination (p < 0.05). Contamination of transport solution is associated with modifiable risk factors, such as warm ischemic time. Measures to minimize contamination should be employed to avoid unnecessary tissue discharges.