Relationship between Virucidal Efficacy and Free Iodine Concentration of Povidone-Iodine in Buffer Solution.

Povidone-iodine solutions prepared to various concentrations (0.01, 0.1, 1 and 10%) with 0.2M phosphate buffer (pH 7.0) (PVP-I PB) were analyzed to determine their free iodine concentrations using membrane permeation cells, and their inactivation effects on three viruses (influenza A virus, poliovirus type 1 and adenovirus type 3) were examined. The free iodine concentrations in the 0.01-10% PVP-I PB were determined to be 1.84, 4.88, 1.58 and 0.17 ppm (approximate values), respectively, with the maximum obtained for the 0.1% solution. The virucidal efficacy of these PVP-I PB against poliovirus type 1 and adenovirus type 3 was found to be generally dependent on free iodine concentration, with the 0.1% solution being the most effective. Influenza A virus was inactivated with an action time of 15 s at all four concentrations examined. The results of this study suggested an association between free iodine concentration and virucidal efficacy for the 0.01-10% PVP-I PB.

Microbial contamination of surgical instruments used for laparotomy.

BACKGROUND: The aim of this study was to determine the risk of contamination of surgical instruments according to the type of instrument and the surgical procedure. METHODS: Microbiologic examination was conducted on 140 pairs of forceps used in 24 elective laparotomies. These included 60 pairs of tissue forceps and 80 pairs of DeBakey forceps. Microbes on their surface were recovered using a membrane filter method. Adenosine triphosphate assay was also performed simultaneously in each pair of forceps. RESULTS: A total of 66 strains of microbes was recovered from 44 collected instruments (31%), with microbial counts ranging from 0 to 296 colony-forming units. Among the recovered microbes, gram-positive cocci were dominant [corrected]. The remaining microbes included 6 strains of gram-positive rods and 4 strains of gram-negative rods. The most common organism was Staphylococcus epidermidis, followed by S hominis and S warneri. Residual adenosine triphosphate was not correlated with the number of recovered microbes. CONCLUSION: Surgical instruments tend to be contaminated during operations by microbes that inhabit the skin and organs. Surgical instruments could act as fomites for the pathogens of surgical site infection even if the surgical field is not apparently contaminated, through application of appropriate practices adhering to surgical site infection guidelines.

Evaluation with a focus on both the antimicrobial efficacy and cumulative skin irritation potential of chlorhexidine gluconate alcohol-containing preoperative skin preparations.

BACKGROUND: Important characteristics for ideal skin preparations include long-lasting antimicrobial efficacy and low potential for skin irritation. METHODS: A total of 55 healthy adult subjects were enrolled to evaluate the antimicrobial effects of 3 test formulations applied to inguinal, abdominal, and antecubital sites at post-treatment time points of 30 seconds, 72 hours, and 7 days. To investigate skin irritation potential, the 3 formulations were tested in a 21-day repeat-insult patch test conducted on the skin of the backs of 23 healthy subjects. RESULTS: The mean log(10) reduction (MLR) at 7 days post-treatment produced by a 79% vol/vol ethanol containing 1% wt/vol chlorhexidine gluconate (1% CHG-EtOH) applied to abdominal sites was significantly superior to that produced by a 10% povidone-iodine solution (2.45 MLR vs 0.90 MLR; P < .05). The 1% CHG-EtOH and a 70% vol/vol isopropanol containing 2% wt/vol CHG (2% CHG-IPA) provided statistically equivalent persistence at 72 hours and 7 days post-treatment. The 1% CHG-EtOH had less skin irritation potential than the 2% CHG-IPA and the 10% povidone-iodine solution, although the differences were not statistically significant (P > .05). CONCLUSION: Considering its persistent effect and low skin irritation potential, the 1% CHG-EtOH preparation is expected to perform well in surgical site preparation to reduce the risk of surgery- and catheter-related bloodstream infection.

A comparative clinical study focusing on the antimicrobial efficacies of chlorhexidine gluconate alcohol for patient skin preparations.

Comparative efficacy study data showed that skin preparations formulated with more than 0.5% chlorhexidine gluconate (CHG) in alcohol produced significant reductions in microbial populations at the inguinal, abdominal, and antecubital sites at each sample time (P < .05) relative to baseline, and there were no significant differences statistically, including persistent effects within 24 hours (P > .05). It would be reasonable to expect that a 1% CHG-ethanol skin preparation (with >0.5% CHG in alcohol) could be chosen in Japan that would perform well and have promising potential for catheter preparation/maintenance preparation with consideration for recommendation of the Centers for Disease Control and Prevention's guideline issued in 2011.

Effect of ethanol on antigenicity of hepatitis B virus envelope proteins.

Hepatitis B e antigen-positive human serum was treated with 50-90% ethanol at room temperature for 1-60 min, then the antigenicity of S antigen (hepatitis B surface antigen, in a narrow sense) was determined by radioimmunoassay and the antigenicities of pre-S1 and pre-S2 antigens were measured by enzyme immunoassay. In addition, hepatitis B virus (HBV) DNA in the treated serum was detected by polymerase chain reaction. All antigenicities markedly decreased within 60 min at an ethanol concentration of 70-80%, and the decrease was faster in pre-S1 and pre-S2 antigens than in S antigen. Although HBV DNA remained in all ethanol-treated serum samples, no HBV DNA was detected after treatment with 1% sodium hypochlorite for 1 min. Based on the results, we speculate that one mechanism of loss of HBV infectivity by ethanol is the inhibition of virus binding to hepatocytes.