MICROBIAL RESISTANCE TO BIOCIDES

The development of microbial resistance to antibiotics and the threat this represents to antibiotic use in clinical practice is a real concern. The general conclusion by the scientific and medical community is that the main cause of the problem is inappropriate use of antibiotics in clinical practice - although use of antibiotics in veterinary medicine and agricultural feedstuffs may also be involved. A number of scientists have also considered the possibility that use of biocids could be an additional contributory factor.

The IFH Scientific Advisory Board have prepared a review paper of the current scientific data regarding microbial resistance to biocides and antibiotics in order to evaluate whether:

1. biocide use has, or could have an impact on antibiotic resistance in clinical practice
2. biocide use encourages or could encourage the development of microbial resistance to biocides
3. practical implications indicate the need for a change in policy on biocide usage in the domestic setting.

This review paper is available as a PDF file. Download the IFH Scientific Review on Microbial Resistance and Biocides. Download Adobe Acrobat Reader for free here.

IFH CONSENSUS STATEMENT ON MICROBIAL RESISTANCE AND BIOCIDES 

The following represents consensus statement of the IFH board, based on this detailed review of the currently available scientific data:

• Whilst laboratory studies have shown potential links between the development of reduced susceptibility to certain types of biocides and the development of reduced susceptibility to antibiotics under certain conditions, there is no evidence that biocide use has been a significant factor to date in the development of antibiotic resistance in clinical practice - antibiotic misuse is the most significant causative factor.
• It must be borne in mind that as growing antibiotic resistance continues to reduce our ability to treat certain infections, then infection prevention through good hygiene - not only in hospitals but also in the community - becomes of even greater importance.
• Since biocides form an integral part of infection prevention through good hygiene, it is important to address concerns that use of biocides may contribute to the development of biocide resistance in practical use. Although laboratory studies provide evidence that prolonged exposure to low levels of certain biocides can be associated with reduced microbial susceptibility, this decreased susceptibility is small relative to concentrations of biocides used in practice. There is currently no evidence to suggest that biocide usage at its current levels (i.e in the domestic and other settings) compromises the effectiveness of hygiene procedures under in-use conditions.
• It is important to recognise that by reducing the number of infection outbreaks through effective hygiene, the number of antibiotic courses prescribed can be lowered, which can in turn reduce the impact of antibiotic resistance, i.e as part of a responsible hygiene policy correct biocide use can contribute to controlling the impact of antibiotic resistance. Thus the possible risks associated with reduced susceptibility to antimicrobials must be weighed against the risks of not using disinfection where hygiene cannot be achieved by other means.
• Education and advice on these issues is important so that health professionals and the public recognise the important benefits of infection prevention through good hygiene and are more fully informed about the possible threats from antibiotic misuse.

Laboratory studies have shown that bacteria possess mechanisms whereby a link between biocide exposure and the development of biocide and antibiotic resistance can exist. For this reason it is important to ensure biocides are used responsibly as part of a good hygiene routine in the domestic setting in order to avoid the possibility of any impact on antimicrobial resistance in the future:

• they should not used be indiscriminately and irresponsibly
• where used they should be used, wherever possible, at concentrations and under conditions which give rapid and effective kill
• they should be used in a way which as far as possible avoids the build up of residues of biocide which might encourage the selection of resistant strains
• it is important to continue to research and to monitor these issues.