Journal of Hospital Infection (1984) 5, 96-99

SHORT REPORT

Whole body disinfection with chlorhexidine: is shower bathing more effective than bathing?

N. J. Mitchell

Public Health Laboratory, Royal Shrewsbury Ilospital, Mytton Oak Road, Shrewsbury S Y3 8XN

Summary: Whole body washing with chlorhexidine gluconate solution HI’ (equivalent to 4 per cent w/v chlorhcxidine gluconate) achieved a variable reduction in total skin microbial colony counts whether applied in a standard bath or a shower bath. So significant differences between the two techniques were demonstrable.

Introduction

It has been standard practice in hospitals for many years for patients undergoing elective surgery to be given a bath soon after admission in the belief that this could effectively reduce the number of microbes normally resident on the skin. When it became known that skin bacterial colony counts actually rose and remained elevated after two or three baths when un- medicated soap was used for either washing (Davies et al., 1977) or shower bathing (Rrandberg and Andersson, 1980) various antiseptic detergent preparations were introduced. Chlorhexidine solution has been shown to reduce the numbers of bacteria on the hands (Lowbury and Lilly, 1983) and it has been demonstrated that aqueous cetrimide/chlorhexidine followed by chlorhexidine in alcohol can remove almost completely superficial and deep aerobic and anaerobic skin bacteria (Nielsen et al., 1975). At least one study has shown a reduction in the incidence of wound’infection in a vascular surgical unit in one group of patients who had repeated pre-operative shower baths using chlorhexidine solution on the entire body compared with a second group who had local washing of the operation site followed by local disinfection with alcoholic chlorhexidine (Urandberg et al., 1980). Whole body disinfection with chlorhexidine shower bathing can reduce the total number of skin bacteria but there are many hospitals still using standard baths with the addition of chlorhexidine. The purpose of this study is to assess whether shower bathing with chlorhexidine is significantly more efficient than chlorhexidine in a standard bath for reducing the total skin bacterial population.

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C 1984 The IIospital Infectton Socirty

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98 N. J. Mitchell

Methods

One male volunteer undertook to take a shower bath or a standard bath once a week following a randomization scheme. Prior to each wash alginate swabs were moistened with nutrient broth. The subject then rubbed a 7 cm2 area of skin in a standardized manner. The selected areas sampled were the left axilla and perineum. Samples were also taken from the umbilicus and anterior nares by rotating the swab 10 times.

After rinsing the body in water, 15 ml of chlorhexidine solution (4 per cent wiv chlorhexidine detergent) were rubbed by hand for 1 min over the entire body including the face but excluding the scalp. ‘l’he subject then entered the shower bath or the standard bath and washed for about another minute. The hair was kept dry. ‘I’his was followed by a second application of chlorhexidine and a further wash. After drying the body with a freshly laundered towel the sampling procedures were repeated. After sampling, each swab was placed in transport medium consisting of lecithin 0.3 per cent, ‘I’ween 80 2.0 per cent in 10, per cent ‘I’ryptone Soya Broth in distilled water. The following morning the samples were shaken for 15 min on a microshaker (‘Cooke AM 69’). Tenfold dilutions were prepared from which pour plates were prepared containing a medium of Tryptone Soya Broth, lecithin 0.3 per cent and Tween 80 2.0 per cent added to melted nutrient agar. The culture plates were incubated aerobically at 30°C for 5 days. Colony counts were performed using a ‘Gallenkamp’ illuminated colony counter.

Results

These results are shown in Table 1. The mean number of counts with the range and the number of observations upon which each was based, before and after each experiment are given. ,‘I’he mean differences after bathing or shower bathing are given with the range, and the statistical significance of these within group differences have been assessed by the Wilcoxon Signed Rank Test. The comparison of bathing and shower bathing with respect to the differences in the counts has been made using the Wilcoxon Rank Sum ‘I‘est .

Statistically significant reduction in bacterial colony counts occurred in the axilla after shower baths (P<O.Ol), in the umbilicus after standard bathing (P< 0.01) and in the perineum after shower baths and standard baths (P<O.Ol). Overall there was no significant difference in reduction of skin microbial colony counts in the selected sampling sites after either whole body shower baths or standard baths.

Discussion

It is well known that total bacterial colony counts on the skin vary significantly from day-to-day in any one subject as well as in different areas of the body surface. In an attempt to allow for some compensation for these

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variables this study was performed by one volunteer who was able to adapt to a system of standardized bathing and sampling techniques more rigorously than might have been possible with several volunteers. It vvas surprising that there was no consistent reduction of skin flora in all the sampled areas that was statistically significant. Neither chlorhexidine with standard baths nor shower baths showed much effect on the total colony counts in the anterior nares. Shower baths were much less effective than standard baths for disinfecting the umbilicus although this technique was more effective in disinfecting the axilla. Both shower baths and standard baths were efficient in reducing the number of microbes in the p.erineum, but there was no significant difference between the two bathing techniques.

Whole body disinfection with chlorhexidinc solution has some effect in reducing skin microbial flora, especially in the perineal area. This study has failed to demonstrate any superiority of shower bathing over standard bathing.

I should like to thank Imperial Chemical Industries for providing chlorhexidine used in this study together with neutralize fluids; and Elaine Laws, Statistics Section, ICI for the statistical advice and analysis.

References

Brandberg, A. & Andersson, I. (1980). Whole body disinfection by shower bath with chlorhcxidine soap. Problems in the Control of Hospital Infection, Royal Society of Medicine International Congress Series No. 23, 6570.

Brandberg, A., Holm, J., IIammarsten, J. & Shersten, ‘I?. (1980). Postoperative wound infections in vascular surgery--effect of pi-e-operative whole body disinfection by shower-bath with chlorhexidinc soap. In Problems in the Control of IIospital Infection, Royal Society of Medicine International Congress Series, So. 23, 71-75.

Davies, J., Babb, J. Ii., Ayliffe, G. A. J. & Ellis, S. H. (1977). The effect on the skin flora of bathing with antiseptic solutions. Journal of Antimicrobial Chemotherapy 3, 473 481.

L,owbury, E. J. L. & Lilly, H. A. (1973). IJ se of chlorhexidine detergent solution (‘Hibiscrub’) and other methods of skin disinfection. British Medical ~ourncrl 1, 510 515.

Nielson, M. I,., Raahave, 13.. Stage, J. G. & Justesen, ‘I’. (197.5). Anaerobic and aerobic skin bacteria before and after skin disinfection with chlorhexidine: An experimental study in volunteers. Journal of Clinical Pathology 28, 793-797.