Evaluation of procedures for hygienic hand-disinfection: controlled parallel experiments on the Vienna test model

Abstract

SUMMARYControlled parallel experiments were performed on the Vienna test model for the evaluation of procedures for hygienic hand-disinfection in three laboratories (Vienna, Mainz, Birmingham). The degerming activity of four procedures, each taking 1 min, was assessed repeatedly and compared with that of a standard disinfection procedure (ST) using isopropanol 60 % (v/v). The mean log reductions (mean log RF) for each procedure were as follows: n-propanol 50 % (v/v) 4-85 and 5-14 in Vienna (V) and Mainz (M) respectively, ethanol 70 % (v/v) + chlorhexidinegluconate 0-5 % (w/v), 4-01 (V), 3-76 (M) and 4 00 in Birmingham (B). Washing procedures were less effective, mean log RF 's of 3-19 (V), 3 49 (M) and 3 04 (B) were obtained with povidone-iodine soap, and 2-91 (V), 3-37 (M) and 3-27 (B) with a liquid phenolic soap. Analysis of variance on the data from Vienna and Mainz revealed significant differences of means not only between procedures ('preparations ') but also on repeat testing. To compensate for the influence of variables such as test subjects, laboratory and day, the Vienna test model provides a method of standardization by testing a ST in parallel with the test procedure (P).Standardization of the results was obtained by pair-wise substraction, log RFp1-log RFSTi. Analysis of variance on the resulting values demonstrated that comparability of the results between laboratories and on repeat testing was achieved. The relative variation of the measurements within the laboratories ranged from 0-9 to 4-2 %. As assessed by power-analysis, a disinfection procedure will be detected as significantly (P = 0-1) inferior to the standard processes in 95 of 100 experiments if it produces a mean log RF that is at least 0'55-0 65 log units smaller than that of the standard.

Bactericidal and Virucidal Activity of Povidone-Iodine and Chlorhexidine Gluconate Cleansers in an In Vivo Hand Hygiene Clinical Simulation Study

“…However, PVP-I (7.5 or 10%) has been shown to achieve significantly higher removal rates than CHG 4% and plain soap against other bacteria, including Staphylococcus aureus, MRSA and A. baumannii [30,31,33,36]. It should be noted that alcohol rubs have outperformed PVP-I and CHG in removing E. coli in some studies [32,36,37]. The findings of our virucidal study are in agreement with the results of a previous study by Steinmann et al [35] that used MNV as a test organism in a modified finger pad test based on the ASTM E 1838 [34], with modifications derived from the EN1500 [11].…”

The Effect of a Scenario based Hand Hygiene Education Program on Hand Hygiene Knowledge, Hand Hygiene Perception, Hand Hygiene Compliance and Hand Hygiene Method in Nursing Students^*

“…The majority of studies of alcohols have evaluated individual alcohols in varying concentrations. Other studies have focused on combinations of two alcohols or alcohol solutions containing limited amounts of hexachlorophene, quaternary ammonium compounds, povidone-iodine, triclosan, or chlorhexidine gluconate (61,93,(100)(101)(102)(103)(104)(105)(106)(107)(108)(109)(110)(111)(112)(113)(114)(115)(116)(117)(118)(119).…”

“…Alcohol-based products are more effective for standard handwashing or hand antisepsis by HCWs than soap or antimicrobial soaps (Table 3) (25,53,61,93,(106)(107)(108)(109)(110)(111)(112)119,(143)(144)(145)(146)(147)(148)(149)(150)(151)(152). In all but two of the trials that compared alcohol-based solutions with antimicrobial soaps or detergents, alcohol reduced bacterial counts on hands more than washing hands with soaps or detergents containing hexachlorophene, povidone-iodine, 4% chlorhexidine, or triclosan.…”

Hand Hygiene

“…Concentrations are given as either percentage of volume (= ml/100 ml, abbreviated % v/v), percentage of weight (= g/100 g, abbreviated % m/m), or percentage of weight/volume (= g/100 ml, abbreviated % m/v). Studies of alcohols have evaluated either individual alcohols in varying concentrations (most studies), combinations of two alcohols, or alcohol solutions containing small amounts of hexachlorophene, quaternary ammonium compounds (QAC), povidone-iodine, triclosan or CHG. 137,221,[267][268][269][270][271][272][273][274][275][276][277][278][279][280][281][282][283][284][285][286] The antimicrobial activity of alcohols results from their ability to denature proteins. 287 Alcohol solutions containing 60-80% alcohol are most effective, with higher concentrations being less potent.…”

“…Table I.11.6 summarizes a number of studies that have compared alcohol-based products with plain or antimicrobial soaps to determine which was more effective for standard handwashing or hand antisepsis by HCWs (for details see Part I, Section 11.13). 88,125,137,221,223,[273][274][275][276][277][278][279]286,[313][314][315][316][317][318][319][320][321] The efficacy of alcohol-based hand hygiene products is affected by a number of factors including the type of alcohol used, concentration of alcohol, contact time, volume of alcohol used, and whether the hands are wet when the alcohol is applied. Small volumes (0.2-0.5 ml) of alcohol applied to the hands are no more effective than washing hands with plain soap and water.…”