The effectiveness of hand hygiene procedures in reducing the risks ...

S46 Vol. 35 No. 10 Supplement 1 Bloomfield et alTable 11. Efficacy of handwashing and alcohol-based hand sanitizers in preventing transfer of hepatitis A and felinecalicivirus from fingertips to lettuceHepatitis AFeline calicivirusParticles transferredto lettuce, %Particles remainingon hands, %Particles transferredto lettuce, %Particles remainingon hands, %No treatment 9.2 18Handwashing 0.39 6.5 0.4 762% Ethanol, 20 seconds 0.64 64 2.1 1375% Ethanol, 20 seconds 0.46 24 1.2 17homemakers in New York 180 showed that a singlehandwash had little impact, with mean log counts of5.72 before compared with 5.69 after handwashing.Another study with 52 office workers and studentsshowed a mean log prewash count of 4.81 comparedwith 5.07 postwash. 181 Kampf and Kramer 173 also reviewedstudies from health care settings in which increasedbacterial counts were found on the handsafter handwashing, and handwashing failed to preventtransfer of bacteria from hands to surfaces. Althoughthere are no data available to confirm this, increasesin contamination may result from sweating inducedby hot water, which flushes resident bacteria fromthe sweat glands onto the hand surface or aids detachmentof bacteria attached to skin scales.It is important to bear in mind that, although soapand water removes contamination from the hands,soap itself has a limited antimicrobial effect, whichmeans that contamination will be transferred to thesink. Hospital studies show that Pseudomonas aeruginosaand Burkholderia cepacia 182 can form reservoirsof contamination in sink waste pipes and can be asource of infection at times when splashes of contaminatedwater come in contact with hands. Mermel et alreported that hands of HCWs became recontaminatedfrom faucet handles during a Shigella outbreak. 183Soap bars also have the potential to spread contaminationfrom person to person via the hands. 88Efficacy of ABHSABHS are formulations that contain either ethanol 1-propanol or 2-propanol or a combination of these products.Their antimicrobial activity is attributed to theirability to denature proteins. Although products containing60% to 95% alcohol are most effective, higherconcentrations are less effective because proteins arenot easily denatured in the absence of water. A rangeof in vivo and in vitro studies have been carried outto determine the effectiveness of ABHS and are reviewedby Boyce and Pittet, 172 Kampf and Kramer, 173and Sickbert-Bennet et al. 169In vivo panel testing of ABHS. In Europe, the efficacyof ABHS is established by panel tests that determinethe reduction in the number of organismsreleased from artificially contaminated hands. Thetest applicable to ABHS is the Committee EuropeanNormalisation Hygienic Handrub Test EN1500. 184 Inthis test, E coli is inoculated onto the hands and dried.The sanitizer is applied to the hands with a rubbingaction for a specified period. The residual number ofbacteria present on hands is assessed pre- and posttreatmentby a rinse-sampling process and the logreduction determined. To claim that a product is a hygienichandrub, it must produce a log reduction at leastequivalent to that produced by a reference productcontaining 60% vol/vol 2-propanol (mean, 4.24 log in1 minute; range, 3.17-6.46).In vivo panel testing against bacterial strains. Data fromin vivo panel tests, summarized in Table 12, indicatethat ABHS show good and rapid activity against bacterialstains such as E coli and S aureus. Efficacy is atleast as good, if not better, than that achieved byhandwashing with soap (Table 10); log reductions obtainedafter a 30-second contact period were of the orderof 3.4 to 3.7 or more compared with 1.8 to 2.8 fora 30-second handwashing process. Boyce and Pittet 172conclude that, typically, log reductions of the releaseof test bacteria from artificially contaminated handsaverage 3.5 log after 30 seconds and 4.0 to 5.0 logafter 1 minute.Paulson et al 185 compared the efficacy of ABHS containing62% ethanol (contact time 5 minutes) withhandwashing against S marcescens, which showedthat handwashing (20 seconds rubbing followed by30 seconds rinsing) produced a log reduction of 2.29compared with 3.83 for the ABHS. Hammond et al 186recorded a 2.84-log reduction for 62% ethanol againstS marcescens in 10 seconds using the ASTM method.Sickbert-Bennet et al, 174 however, showed that exposureof S marcescens to 60% to 62% ethanol for 10 secondsproduced only a 1.15- to 1.55-log reductioncompared with 1.87-log reduction for handwashingfor 10 seconds, when tested by the ASTM 1147method.