ABSTRACT
Survival of bacteria and release of the endotoxin from the bacteria with and without ultraviolet irradiation in three kinds of dialysate were investigated. The results obtained are as follows: (1) No growth of S. aureus, E. coli, P. aeruginosa, Aspergillus and C. albicans in the saturated dialysates tested were observed. (2) All of the bacterial cells tested here is gradually, and naturally spontaneously inactivated in all the dialysates. (3) Among the dialysates tested, the saturated dialysate, AF-2, is the most effective for inactivating P. aeruginosa ATCC, but the effect depends upon the isolates of P. aeruginosa. (4) The inactivating effect was somewhat decreased when the saturated AF-2 solution was diluted, but the killing effect was still maintained. (5) The bacterial cells are constantly and significantly inactivated by UV irradiation, especially by the direct irradiation. The indirect irradiation, i.e., through glass, has remarkably less effective than the direct one. However, a tendency of the decrease of bacterial cells by the indirect irradiation is maintained with the killing effect of the dialysated, especially in the case of AF-2 solution. (6) No significant increase of endotoxin was observed, even when the bacterial cells were killed by UV irradiation. Therefore, it is recommended to use UV irradiation for inactivating the bacteria. From the results obtained here, it is indicated that there is no possibility of the growth of naturally contaminated bacteria in the dialysates, and is an effectiveness of the use of UV irradiation for inactivating the bacteria cells, in terms of release of the endotoxin from the dead cells.
