Residual amount of vancomycin hydrochloride in vials after use.

We macroscopically observed vials of vancomycin hydrochloride (VCM) for injection (0.5 g/vial) dissolved in various solvents, and determined the presence or absence of residual VCM crystals. In addition, the residual VCM in vials after use was measured using a bioassay. In vials evaluated after use, the percentage of vials in which VCM crystals were macroscopically confirmed, the mean residual amount of VCM in the vials (residual %), and the percentage of vials with ≥50 mg (10 %) of residual VCM were 28.1 %, 15.0 ± 7.5 mg (3.0 %), and 0 %, respectively, after the dissolution of a single VCM vial in 10 ml of distilled water for injection (n = 57); 63.8 %, 30.2 ± 19.1 mg (6.0 %), and 16.1 %, respectively, after the dissolution of a single VCM vial in 100 ml of physiological saline (n = 224); and 72.2 %, 38.5 ± 28.0 mg (7.7 %), and 33.3 %, respectively, after the dissolution of two VCM vials in 100 ml of physiological saline (n = 18). The mean residual VCM amount was greater when using physiological saline than when using distilled water for injection as a solvent. These results show the need to follow the dissolution method described in the package insert, which calls for the addition of 10 ml of distilled water for injection to each 0.5 g VCM vial.

Efficacy of disinfectants and hot water against biofilm cells of Burkholderia cepacia.

The effects of various disinfectants and hot water on planktonic cells and biofilm cells of Burkholderia cepacia were investigated. The survival rate of viable B. cepacia cells in suspension decreased to 0.001% or lower within 15 s of exposure to 0.5% benzalkonium chloride, within 30 s of exposure to 0.5% alkyldiaminoethyl glycine, or within 1 min of exposure to 0.1% alkyldiaminoethyl glycine, and decreased to about 0.1% with 60 min of exposure to 0.1% benzalkonium chloride or 0.5% chlorhexidine gluconate, but did not decrease to 1% or less with 60 min of exposure to 0.1% chlorhexidine gluconate. There were no effects of 0.1% and 0.2% chlorhexidine gluconate and 0.1% benzalkonium chloride against biofilm cells of B. cepacia, and 0.5% chlorhexidine gluconate, 0.5% benzalkonium chloride and 0.1% alkyldiaminoethyl glycine were barely effective against biofilm cells even after 60-min exposure. On the other hand, both planktonic cells and biofilm cells of B. cepacia were eradicated within 15 s by sodium hypochlorite, povidone-iodine, 80% v/v ethanol, and hot water at 65 degrees C or higher.