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8.2 SHORTCOMINGS OF TRADITIONAL TEST METHODS 8.2.1 HYGIENIC HANDWASH AND HANDRUB; HCW HANDWASH AND HANDRUB A major obstacle for testing hand hygiene products to meet regulatory requirements is the cost, which can be prohibitive even for large multinational companies. Cases in point are the extensive and varied evaluations as specified in the TFM 135 . The TFM requires in vitro determination of the antimicrobial spectrum of the active agent, of the vehicle and of the final formulation by assessing the MIC with approximately 1000 microbial strains, half of which must be freshly recovered clinical strains. Furthermore, time-kill curves have to be established and studies on the development of resistance have to be done. In vivo, at least 54 volunteers are necessary in each arm to test the product and a positive control, hence a minimum of 2 x 54 subjects. The immense expenditure would, however, be much smaller if the same subjects were used to test both formulations concurrently in two runs in a cross-over fashion, as described in EN 1499 and EN 1500 137,138 . The results could then be intra-individually compared, thus allowing a considerable reduction in sample size at the same statistical power. Another shortcoming of existing test methods is the duration of hand treatments which require volunteers to treat their hands with the hand hygiene product or a positive control for 30 seconds 135 or 1 minute 137 despite the fact that the average duration of hand cleansing by HCWs has been observed to be less than 15 seconds in most studies 70,148-153 . A few investigators have used 15-second handwashing or hygienic hand antisepsis protocols 93,154- 157 . Therefore, almost no data exist regarding the efficacy of antimicrobial soaps under conditions in which they are actually used. Similarly, some accepted methods for evaluating waterless antiseptic agents for use as antiseptic handrubs such as the reference hand antisepsis in EN 1500 138 , require that 3 ml of alcohol be rubbed into the hands for 30 seconds, followed by a repeat application of the same type. Again, this type of protocol does not reflect actual usage patterns among HCWs. However, it could be argued that equivalence in the efficacy of a test product with the reference is easier to prove with longer skin contact because, if a difference in the efficacy exists, it is greater after longer application times and therefore easier to detect. Or, inversely, to prove a difference between two treatments of very short duration, such as 15 seconds, under valid statistical settings is difficult and requires large sample sizes, i.e. numbers of volunteers. Therefore, a reference treatment which has usually been chosen for its comparatively high efficacy may include longer skin contact than is usual in real practice if the aim is to demonstrate the equivalence of a test product with economically justifiable sample sizes. A further shortcoming relates to the requirements for efficacy. The TFM 135 for instance, requires a hand hygiene product for an HCW handwash in vivo to reduce the number of the indicator organisms on each hand by 2 log within 5 minutes after the first wash and by 3 log after the tenth wash. This requirement is inappropriate to the needs of working in a healthcare setting for two reasons. First, to allow a preparation to reduce the bacterial release by only 2 log within a maximum time span of 5 minutes seems an unrealistically low requirement, as even with unmedicated soap and water a reduction of 3 log is achievable within 1 minute 1,158 . Furthermore, 5 minutes is much too long to wait between two patients. Second, the necessity for residual action of a hand disinfectant in the non-surgical area has been challenged 159-161 . The current group of experts does not believe that for the aforementioned purpose a residual antimicrobial activity is necessary in the health-care setting. Rather, a fast and strong immediate effect against a broad spectrum of transient flora is required to render hands safe, not only in a very short time, but also already after the first application of the
formulation. Therefore, the requirement that a product must demonstrate a stronger activity after the tenth wash than after the first seems illogical. The statistical analysis as suggested by EN 1500 is not optimal because in the case of an inferior efficacy of the product, the difference from the mean reduction achieved by the reference is tested for significance as for a comparative trial rather than for an equivalence trial which would be more appropriate. 8.2.2 SURGICAL HANDWASH AND HANDRUB; SURGICAL HAND SCRUB; SURGICAL HAND PREPARATION As with hygienic hand antisepsis, a major shortcoming for testing surgical scrubs is the resource expenditure associated with the use of the TFM model. The required in vitro tests are the same as described under 8.2.1 (see also Table I.8.1). According to TFM, the in vivo tests require a large number of volunteers corresponding to: n ≤ 2 s2 [za/2 + zb]2 / D2 where s2 is an estimate of the variance (e.g. 1.01), z a/2 = level of significance (e.g. for p = 5% 1.96), z b = power of the test (e.g. for 80% 0.82), and D = the clinical difference of significance to be ruled out (e.g. 20% of the active control’s mean reduction from baseline at a specific time) 135 . For the above example of estimates and with the statistical settings therein, a sample size of 64 subjects per arm of a trial is required if, for example, the comparative active control hand scrub produces a mean reduction at a specific time of 2.5 log-steps and the result of the test product is to be within 20% of this (D = 0.5) 135 . Hence, at least a total of approximately 130 subjects is necessary to test a product together with an active control in the suggested parallel arm design. For some products, this number will even have to be multiplied for concomitant testing of the vehicle and perhaps of a placebo to demonstrate efficacy 135 . This would add up to a total of 520 or even more subjects, in the event that the variance is larger than that mentioned above 135 . As mentioned with the test model for HCW handwashes (see Part I, Section 8.2.1) and described in prEN 12791 145 , this enormous number of volunteers can be much reduced if the tests are not made with different populations of subjects for each arm, but if the same volunteers participate in each arm, being randomly allocated to the various components of a Latin square design, the experiments of which can be carried out at weekly intervals. The results are then treated as related samples with intra-individual comparison. Additionally, it is not clear why the vehicle or a placebo needs to be tested in parallel, if a product is shown to be equivalent in its antimicrobial efficacy to an active control scrub. For the patient and for the surgeon, it is of no interest whether the product is sufficiently efficacious because of the active ingredient only or, perhaps, additionally by a synergistic or even antimicrobial effect of the vehicle. In any case, it is to be hoped that a test product, the efficacy of which can be shown to be equivalent to that of an active control scrub, is superior to a placebo. If not, the active control has been badly chosen. In contrast to the requirement of prEN 12791 where a sustained (or persistent) effect of the surgical scrub is optional, the TFM model requires a product to possess this feature (see above). Whether a sustained (or persistent) effect is necessary or not is a matter for discussion. It is, however, difficult to understand why the efficacy of a scrub is required to increase from the first to the fifth day of permanent use. Ethical considerations would suggest that the first patient on a Monday, when the required immediate bacterial reduction from baseline is only 1 log, should be treated under the same safety precautions as patients operated on the following Friday when, according to the TFM requirement, the log reduction has to be 3.0. Indeed, an immediate effect comparable to the latter reduction is achievable at the first surgical hand scrub after a period of non-use with handrubs containing high concentra-
Page 2 and 3: The WHO Guidelines on Hand Hygiene
Page 5 and 6: CONTENTS INTRODUCTION . ...........
Page 7 and 8: 17. Organizing an education program
Page 11: INTRODUCTION The WHO Advanced Draft
Page 14 and 15: Handwashing. Washing hands with pla
Page 16 and 17: still considered the standard of ca
Page 18 and 19: treatment selectively removes glyce
Page 20 and 21: of the organism on their hands. Mak
Page 22 and 23: 6. MODELS OF HAND TRANSMISSION 6.1
Page 24 and 25: In the 1960s, a prospective, contro
Page 26 and 27: for its ability to reduce the relea
Page 30 and 31: tions of short-chain aliphatic alco
Page 32 and 33: 9.1.3 WATER QUALITY The physical, c
Page 34 and 35: Case study: experience of Egypt The
Page 36 and 37: and both reduced viral counts on ha
Page 38 and 39: activity of chlorhexidine is not se
Page 40 and 41: protein synthesis and alteration of
Page 42 and 43: in micelle structures formed by sur
Page 44 and 45: In all the studies that included pl
Page 46 and 47: isopropyl alcohol) were applied to
Page 48 and 49: 3) Glycerol is added using a measur
Page 50 and 51: in 2005 the costs of an alcohol-bas
Page 52 and 53: infection, risk factors that are la
Page 54 and 55: 11.4.4 SIDE-EFFECTS OF THE SURGICAL
Page 56 and 57: • Repeat the process on the other
Page 58 and 59: 12.2 ALLERGIC CONTACT DERMATITIS RE
Page 60 and 61: particularly when resources are lim
Page 62 and 63: Handrubs are available as gels, sol
Page 64 and 65: 14. HAND HYGIENE PRACTICES AMONG HE
Page 66 and 67: quantified in observational studies
Page 68 and 69: According to behavioural theories (
Page 70 and 71: of water with special leaves) outsi
Page 72 and 73: Furthermore, according to Phra Depv
Page 74 and 75: 16. BEHAVIOURAL CONSIDERATIONS 16.1
Page 76 and 77: and community factors must be consi
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i. ii. iii. iv. v. vi. a) b) Educat
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tion precautions 580 . There are al
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follow the intent 588 . Studies hav
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18. FORMULATING STRATEGIES FOR HAND
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18.2 DEVELOPING A STRATEGY FOR GUID
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1998 (P
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HCWs routinely to wear vinyl gloves
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quality gloves, reuse, shortage of
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• To test for holes, gloves shoul
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Figure l.20.2: Blood safety: crucia
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Consensus recommendations are that
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D. Wash hands with either plain or
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5. SKIN CARE A. B. C. Include infor
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PART III. OUTCOME MEASUREMENTS 1. M
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2. HAND HYGIENE AS A QUALITY INDICA
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can be seen during routine work. Da
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Case study: United Kingdom national
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PART IV. PROMOTING HAND HYGIENE ON
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ated to reinforce its principles (t
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6. PRINCIPLES OF COUNTRYWIDE HAND H
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As many international and national
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debate that resulted in increasing
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23. Lee YL et al. Colonization by S
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Interscience Conference on Antimicr
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122. Vicca AF. Nursing staff worklo
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171. Kauppinen J et al. Hospital wa
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224. Krilov LR et al. Inactivation
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276. Thomas L et al. Development of
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326. Johnson S et al. Prospective,
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34th Interscience Conference on Ant
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423. Kampf G, et al. Influence of a
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474. West DP et al. Evaluation of a
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524. Muto C et al. Hand hygiene rat
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578. Babcock HM et al. An education
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Interscience Conference on Antimicr
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679. Hirschmann H et al. The influe
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729. Martin LS, McDougal JS, Loskos
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Table I.8.1: Basic experimental des
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Table I.9.1: Waterborne pathogens a
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Table I.9.3: Virucidal activity of
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Table I.9.4: Studies comparing the
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Table I.9.6: Studies comparing the
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Table I.14.1: Hand hygiene frequenc
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Table I.14.2: Hand hygiene adherenc
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Table I.15.1: Hand hygiene indicati
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Table I.18.1: Strategies for succes
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Table l.20.1: Possible problems and
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Table I.21.1. Hand hygiene research
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Table I.21.1: Hand hygiene research
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Table I.21.2: Unsolved issues for r
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Table III.2.1: Quality indicators r
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Table V.3.1: Examples of public inf
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Table V.4.1: Examples of national p
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Table V.5.1: The public information
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APPENDIX 1. DEFINITIONS OF HEALTH-C
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APPENDIX 2. HAND AND SKIN SELF-ASSE
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Data in coloured cells can be chang
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NHS NICU n-P NPSA NA NS OPD PACU PA
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AUTHORS: John Boyce Saint Raphael H
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Garance Upham People’s Health Mov
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