As International Infection Prevention Week (#IIPW) continues, Prof Sally Bloomfield writes a guest blog on the principles of breaking the chain of infection. Whilst the blog is focused on home and everyday life settings, the principles are relevant to healthcare facilities too!

This is international Infection Prevention Week. To address this year’s theme “Breaking the Chain of Infection” the International Scientific Forum on Home Hygiene (IFH) has produced a simple online resource Breaking the Chain of Infection.

This is a great opportunity to get this concept over to the public, who find it hard to understand – but is the foundation for understanding hygiene in home and everyday life and elsewhere. Healthcare workers now accept that reducing infection in healthcare settings cannot be achieved without also reducing circulation of pathogens in the community.

I would suggest however that hygiene in out-of-hospital settings will not improve until we first change fundamental public misconceptions about hygiene, cleanliness and germs. One problem is that the public still tend to see infection prevention (or hygiene) as “keeping ourselves and our environment clean.”  They want to know the places which “harbour” germs –  where germs “grow” or “lurk”- believing that if they get rid of them they will be safe.  They fail to understand that environmental sites and surfaces are mostly just a “stepping stone” where germs can survive, whilst getting from one human (or animal) to another – and that hygiene is breaking this chain of infection. In reality it is people and animals who “harbour “ germs.

To address this, IFH have developed the concept of targeted hygiene, which this online resource sets out to explain in simple language.  It shows that preventing spread of infections is best achieved by intervening in the places and the times that matter to prevent spread of germs.  In the home, places that matter most are the hands, hand and food contact surfaces, and cleaning utensils.  Clothing and household linens, toilets, baths and basins also contribute, although the risk is probably less than for hands etc.  The times that matter most are those associated with food preparation, using the toilet, respiratory hygiene, taking care of pets, disposing of refuse, and caring for people who are infected or at greater risk of infection.

Misconceptions are also nurtured by our interchangeable use of the words “cleaning” and “hygiene”. We tend to believe a surface that  looks clean is also germ free.  We need to understand that we can only be confident that something is “hygienically clean” if it has been  treated (cleaned, or cleaned and disinfected) in the recommended way e.g. we have washed our hands “properly”.

Another problem is our confusion about what a “germ” actually is. From childhood images we develop a vision that our world is teeming with germs which are nasty, green, slimy, invisible enemies to be searched and destroyed.  We are told that millions of germs are found on the toilet seat or the chopping board, but nobody tells us that most of these so-called germs are our “old friends”, or points out that this is very different from, for example, handling raw chicken where harmful microbes are likely, and which needs to be dealt with promptly. Constant use of the word germ tends to spread fear, where none exists. The e-bug project, is an initiative aimed at ensuring children have an understanding of targeted hygiene thankfully avoids using the term “germs”.¹

We will also be unable to promote better hygiene whilst we remain wedded to the hygiene hypothesis misnomer – that children protected by “too much hygiene” are more likely to get allergies.  The evidence increasingly suggests that increases in inflammatory disease  are the combined result of lifestyle, medical and public health changes which have deprived us of exposure to vital  “old friends “ microbes – and that these microbes are not “germs” but the largely non harmful species which inhabit the human and animal body, and our natural environment. The changes include modern sanitation, clean water and food, c-section (rather than vaginal delivery) childbirth, less breast feeding, fewer siblings, less outdoor activity, and urbanisation.  It also appears that that essential communication between our “old friends” and the immune system is mediated by the “human microbiome” and that excessive antibiotic use and altered diet can affect the microbiome in a way that increases risks of inflammatory disease.  The idea that home hygiene is the reason is no longer supported. These issues and the evidence are discussed in more detail a recent review, which represents the consensus view of a group allergist, immunologists, microbiologists and infection preventionists.²

Experts now accept that the hygiene hypothesis is a misleading and dangerous misnomer. which is undermining attitudes to hygiene at a time when antibiotic resistance threatens our ability to treat infections. Despite this, the media, although they now talk about the wider issues likely to be the source of immune dysregulation, still constantly refer to the rise in inflammatory disease as the result of “living in an over sanitised world” and “being too clean”. No way could altered diet or too many antibiotics be described as “ living in an oversanitised world”?  Recent media articles (see here and here) which promote unsubstantiated suggestions that reduced handwashing could be a means to sustain a diverse gut microbiome are in direct conflict with public health advice on handwashing which is identified as probably the most important action for preventing spread of infection in all settings.

There is no doubt that, in future, we are going to have to view our microbial world very differently.  Grasping the idea that our human microbiome is essentially an organ which is as vital for our health as our liver and kidneys is very different concept from the germophobic idea of living quite separately from our microbial world

Sally F. Bloomfield

Honorary Professor, London School of Hygiene and Tropical Medicine

Chairman, International Scientific Forum on Home Hygiene (www.ifh-homehygiene.org)

References

1. The e-bug project Perspectives in Public Health 2016; 136 (4) 192-193
2. Bloomfield SF, Rook GAW, Scott EA, Shanahan F, Stanwell-Smith R, Turner P. Perspectives in Public Health 2016; 136(4): 213–224.