Comparison of two methods for assessing the removal of total organisms and pathogens from the skin

Abstract

SUMMARYA standard hand-wash sampling technique was compared with a simple fingerstreak sampling method in assessing the relative effectiveness of a number of alternative preparations used for disinfecting the surgeon's hands (alcoholic 0-5 % chlorhexidine, alcoholic 041% tetrabrom-o-methyl phenol, a 4 % chlorhexidine detergent solution, aqueous 0 5 % chlorhexidine, 2 % 'Irgasan' detergent solution and, as control, bar soap). There was a fairly good correlation between the results of assessment by the two methods after a single disinfection and after six disinfections, three on one day and three on the next. Significant differences were shown in 21 comparisons between treatments when the hand-wash sampling test was used, and 16 of these comparisons also showed a significant difference by the finger-streak test.Staphylococcus aureus was found in hand samplings from 5 out of 8 nurses in the Burns Unit of Birmingham Accident Hospital by the hand-wash sampling method and from 2 of the same 8 nurses by the finger-streak method; the numbers were small, and no Staph. aureus were isolated from the same hands after 1 min. wash in 70 % ethyl alcohol. Similar sampling on 29 nurses in other wards showed Staph. aureus on 3 nurses (one in large numbers) by the hand-wash technique and on 1 nurse by the finger-streak test; in only 1 nurse whose hands showed Staph. aureus before disinfection was the organism found, by hand-wash sampling, after disinfection.Parallel sampling of nurses' hands after washing with soap and water and after disinfection with 95 % ethanol showed larger numbers of Staph. aureus in a hospital for skin diseases than in a general hospital, and a lower incidence and somewhat lower density of Staph. aureus after ethanol treatment than after washing with soap and water; Gram-negative bacilli, on the other hand, were commoner on hands in the general than in the skin hospital, and present in much smaller numbers after disinfection with ethanol than after washing with soap and water.Antibiotic sensitivity tests showed the frequent recurrence on the hands of some nurses of multi-resistant Staph. aureus with resistance patterns similar to those found in infective lesions in some of the patients; different sensitivity G. A. J. AYLIFFE AND OTHERS patternis were usually found in staphylococci isolated from the nose. Even in wards where many patients were infected, carriage by nurses' hands of a particular strain of Staph. aureus did not seem to last for more than a few days.

Failure of hand disinfection with frequent hand washing: a need for prolonged field studies

“…The results obtained by this method of sampling -as well as by the finger-streaking method -have been found to be in accordance with those obtained by hand washing technique (Ayliffe et al, 1975;Ojajarvi, unpublished results). The simplicity of the method makes it possible to carry out prolonged studies in practical conditions.…”

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.…”

“…48,268,271,[280][281][282][283][284][285][286]301,313,316,[460][461][462][463] In many of these studies, bacterial counts on the hands were determined immediately after using the product and again 1-3 hours later. The delayed testing is performed to determine if regrowth of bacteria on the hands is inhibited during operative procedures; this has been shown to be questionable by in vivo experiments only if a suitable neutralizer is used to stop any prolonged activity in the sampling fluids and on the counting plates.…”

“…464 Alcohol-based solutions were more effective than washing hands with plain soap in all studies, and reduced bacterial counts on hands to a greater extent than antimicrobial soaps or detergents in most experiments. 268,271,[280][281][282][283][284][285][286]301,313,316,[461][462][463] Table I.11.10 shows the log 10 reductions in the release of resident skin flora from clean hands immediately and 3 hours after use of surgical handrub products. Alcohol-based preparations proved more efficacious than plain soap and water, and most formulations were superior to povidone-iodine-or CHG-containing detergents.…”