Isolation of Microorganisms and Effectiveness of Sterilization from Aortic Valve Allografts

Choi, Young Sook

Abstract

BACKGROUND: All allografted heart valves procured from brain dead multiorgan donors should be considered contaminated. If propriety procurement, disinfection and storage of allografted heart valves are done, it allows significantly better host tissue ingrowth into the implanted leaflets and maintains the viability of the allograft valve over a prolonged period after transplantation. Therefore, it is necessary that any potential contaminants should be eliminated by using adequate antibiotic disinfecting solutions for minimum loss of tissue viability. The author performed this study to evaluate the microorganisms isolated from allografted heart valves and the effectiveness of CLPV (Cefoxitin, Lincomycin, Polymyxin B, Vancomycin) antibiotic solutions for sterilization.
METHODS
The samples were procured from 10 pigs. A total of 130 cultures were done from 40 samples of touch swab, 10 samples of saline transport solution and each of 40 samples of nutrient media with antibiotics preserved for 24 hours and 14 days at 4degreesC. Among the total 130 samples, 50 were sampled before antibiotics treatment and another 80 were sampled after antibiotics treatment. Aerobic, anaerobic, mycobacterial and fungal cultures were done using all specimens.
RESULTS
A total of 209 microorganisms were isolated from 23 out of 50 samples before antibiotics treatment. Among the 209 microorganisms, aerobes were found in 135 (65%), anaerobes in 57 (27%) and fungi in 17 (8%), respectively. Aerobic isolates were mainly Staphylococcus epidermidis, S. aureus, Enterobacter cloacae and Escherichia coli. Anaerobic isolates were Bacteroides fragilis, Porphyromonas intermedia and Clostridium paraputrificum. Fungal isolates were Candida albicans, C. krusei and Saccharomyces cerevisiae.
CONCLUSIONS
It is necessary that all allografted heart valve for transplantation enter into a sterilization program. In this experiment, pre-treatment cultured organisms were not discovered after antibiotics treatment in all the samples. It was thus concluded that the effectiveness of CLPV solution for sterilization of heart valves was effective. The disadvantage was that the viability of the allograft after sterilization using CLPV solution was reduced. The author, therefore, proves the need for the development of more effective antibiotic mixtures with regard to cellular viability, host ingrowth rate, disinfection efficiency and valve survival rate.