A survey of disinfectant use in hospital pharmacy aseptic preparation areas
The Salvadore Vol 264 No 7088p446-448
March 18, 2000 Original Papers
A survey of disinfectant use in hospital pharmacy aseptic preparation areas
By S. M. Murtough, BSc, Sarah J. Hiom, PhD, MRPharmS, Maria Palmer, PhD, MRPharmS, and A. D. Russell, DSc, FRPharmS
Aim To assess the range and use of disinfectants in UK hospital pharmaceutical aseptic preparation units.
Design Postal questionnaire.
Subjects and Setting Quality control pharmacists throughout the UK.
Outcome measures QC pharmacists' assessments of the type, method of use (including rotation and concentration) of disinfectants in aseptic preparation areas.
Results Phenolics and halogen-releasing agents were most frequently used for floor cleaning. Alcohols were the biocides of choice for critical surfaces such as laminar air flow units. Mops used for floor cleaning were sterilized in 57.1% of cases before use. 64 per cent of respondents employed rotation of disinfectants with the intention of overcoming or preventing the development of biocide-resistant bacteria. In-house validation provided the basis for decisions on the use of disinfectants in most cases.
Conclusion Attitudes towards disinfection have improved greatly in recent years. However, standards do need to be maintained and regular monitoring will help to achieve this.
The number and range of micro-organisms that are resistant to one or more antibiotics is a continual and increasing problem, especially in hospitals.1 With the emergence of pathogens such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and Gram-negative bacteria, for example, Pseudomonas aeruginosa and Acinetobacter spp, which are resistant to multiple antibiotics, there is an increasing need for effective disinfection.2 This is especially true in clean rooms where pharmaceuticals, dressings and instruments are prepared and sterilised.
In 1965, a Public Health Laboratory Service report appeared on the use of disinfectants in hospitals.3 It noted that, in general, there were no disinfection policies in place for the use and concentration of the disinfectants available. The situation has changed markedly since then and now many hospitals do have such policies, but implementation is still frequently unsatisfactory.4 Misconceptions regarding the activity of disinfectants and the nature of bacteria by staff, who may have little microbiology knowledge, still persist.5 Clearly, there is a need for hospital pharmacists to understand the role and uses of disinfectants, the factors that influence their activity, the possibility that microbial resistance can arise and the relevance, if any, of rotation of disinfectants.
This study was designed to assess the range and uses of disinfectants used in United Kingdom hospital pharmaceutical aseptic preparation units, providing baseline information for further studies and potential guideline developments.
A six-question postal survey was sent to 33 UK quality control (QC) pharmacists.
Of 33 surveys sent, there were 28 replies (84.8 per cent), three of which stated that aseptic work was not carried out at that hospital.
The types of biocides used for floors together with their active ingredients and properties are presented in Tables 1 and 2. The most popular groups of biocides in use for floor cleaning were the phenolics and halogen-releasing agents (HRAs) (both 25.6 per cent) followed by the quaternary ammonium compounds (QACs) (23.3 per cent). Detergent was used on its own in one instance, and in rotation with a QAC in three other replies, which stated that a detergent or sanitiser was used.
Table 1: Summary of the responses to question 1a about disinfectants used for floor cleaning
|Trade name||Biocide group||Concentation/dilution and active ingredients||Number|
|Actichlor||Halogen||2.5g tablet in 1.25L water||2|
|Sanichlor||Halogen||(NaDCC) 1.8g tablet in 1L water to give ca 1,000ppm Cl2||1|
|Presept||Halogen||ca 140ppm Cl2||2|
|Milton||Halogen||1 in 10 and 1 in 80||4|
|Haychlor||Halogen||Sodium hypochlorite 1 in 10||1|
and chlorhexidine salt 0.015%
|Tego 2000||QAC||0.5% 1-alkyl-1,5-diazapentane||3|
|Proceine 40||QAC||Alkyl-amino-alkyl glycines||6|
|Detizor||QAC||60ml in 6L||1|
|Clearsol||Clear soluble phenolic||Phenol 1%||5|
|Hycolin||Clear soluble phenolic||15?30% anionic surfactant|
|Stericol||Clear soluble phenolic||1% xylenol||2|
|Virkon||Peroxygen based||49.4% potassium peroxomonosulphate|
4.4% sulphamic acid
13.17% sodium alkyl benzene?sulphonate
|Klericides (various)||Multiple||QAC + ClO2||5|
|QAC = quaternary ammonium compound|
Table 2: Summary of biocide properties (based in part on reference 7)
|Agent||Gram positive||Gram negative||Mycobacteria||Spores||Lipid viruses||Non-lipid viruses|
|Phenolics||High||High||Moderate or inactive||Inactive||High||Inactive|
|Quaternary ammonium compounds||High||Slight||Inactive||Inactive||High||Inactive|
|HRA = halogen releasing agents|
When asked about mop heads, 57.1 per cent of the 21 respondents to this question stated that these were sterilised either daily or before each use, 19.0 per cent cleaned and sterilised the mop head before use and a further 23.8 per cent relied on cleaning alone. Most respondents neglected to quote how often mop heads were renewed, but those that did stated that it was on a daily, weekly or monthly basis.
In response to the question about disinfectant rotation policy, 64.0 per cent of 25 respondents employed such a policy, but in most cases this was only for floor disinfection. There was no agreement between different hospitals as to rotation frequency; weekly, monthly, bi-monthly or six monthly periods were used.
Tables 3 and 4 summarise, respectively, the types of disinfectants used for surfaces in aseptic preparation units and the reasons for using biocides for particular purposes.
The wide variety of floor cleaners in use shows that there is little consistency between hospitals in terms of biocide usage. In a previous hospital survey, phenolics and chlorhexidine were the biocides of choice for disinfection of floors.3 Respondents to the present survey indicated that phenolics are still one of the most popular groups of biocides used for floor cleaning. However, there has also been an increase in the use of QACs and HRAs for this purpose. The increase in use of QACs may be due to their surfactant properties. Many commercial QAC preparations include added surfactants (eg, Proceine 40 Agma contains 15?30 per cent anionic surfactants). It is not clear whether incompatibilities that may arise between cationic and anionic surface-active agents have been taken into account. Halogens are also useful biocides because in many cases they are sporicidal, whereas QACs and phenols are only sporistatic, even at high concentrations.7
Mops can be a serious potential source of contamination. Maurer6 showed that even when mops were soaked in a phenolic disinfectant overnight contaminants could still be harvested and the problem was amplified when the mop head was plastic-based. The main cause of this contamination was Ps aeruginosa. Leigh and Whittaker8 also reported that there was reduced activity when polyurethane mop heads were used with Hycolin at 1 per cent. Dry, dust-attracting mops have been shown to be a source of MRSA.9 It is recommended that sterilisation of mop heads before use is undertaken to prevent the spread of contamination. Furthermore, it should be borne in mind that plastic-based mops might be inhibitory to the bactericidal activity of disinfectant preparations.6,9
The predominance of the use of alcohols to clean bench tops, laminar flow cabinets and isolator surfaces indicates the need for disinfection of these areas, together with consideration of possible material damage by corrosion. Alcohols have rapid bactericidal activity10 and are sporistatic,11 but when used in conjunction with hydrogen peroxide, as was the case in 8 per cent of responses, the activity might be sporicidal, depending on the concentration of peroxide itself.11 The other major advantages of alcohols are their rapid evaporation and lack of residues.
The possible implementation of a rotational disinfectant policy was considered to be an important question in this survey. Unlike the previous edition, the current issue of the "Orange guide"12 does not express any opinion about the benefits, if any, of rotation. Rotation has been considered as being a system of overcoming the possible development of bacterial resistance to a disinfectant. In our survey, 64 per cent of respondents implemented such a policy, supporting proposals that there is no clear-cut evidence that such a policy is advantageous.
There are often multiple sites on or in micro-organisms at which biocides act.13,14 Thus, it has generally been considered that bacterial resistance to these agents might not be a problem. It is, however, known that both natural (intrinsic) and acquired resistance mechanisms might operate.13 Further, a highly specific resistance mechanism to the bisphenol, triclosan, in Escherichia coli has been reported, involving an enoyl reductase.15,16 It has also been claimed17 that widespread usage of cationic biocides in hospitals has resulted in the selection of antibiotic-resistant cocci. Therefore, additional research needs to be undertaken to clarify whether disinfectant rotation is necessary.
Decisions on the choice of biocides are now made mostly on the basis of in-house validations (64 per cent of respondents) with only 16 per cent relying on drug company literature, which in the past might occasionally have been misleading.6
Disinfectant usage in hospitals has improved greatly since the PHLS report3 in 1965, but it is essential that standard operating procedures are accurately prepared and implemented and that studies on use and effect are carried out.
Acknowledgments We thank the United Bristol Healthcare trust and the Welsh school of pharmacy, Cardiff, for jointly funding a research studentship for one of us (SMM).
Mr Murtough is a postgraduate research student in pharmaceutical microbiology at the Welsh school of pharmacy, Cardiff university; Dr Hiom is all-Wales research and development pharmacist, St Marys hospital, Penarth; Dr Palmer is research and development director at United Bristol healthcare trust, Bristol, and Professor Russell holds a personal chair in pharmaceutical microbiology at the Welsh school of pharmacy. Correspondence to Professor Russell at the Welsh School of Pharmacy, Cardiff University, Redwood Building, King Edward VII Avenue, Cardiff CF10 3XF.
Citation: The Salvadore URI: 20000884
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