Back to the floor..

flooringA little while ago I blogged about the excellent study from Nottingham that demonstrated significant VRE and MRSA contamination on socks used to prevent falls in the hospitalised elderly. This has been followed by another paper suggesting that shoe coverings undurprisingly become contaminated. So, what? How does this really impact on transmission? A new study from Curtis Donskey’s group has looked at hand contamination in patients directly relating to floor contamination. Continue reading

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Diluting the efficacy of hydrogen peroxide room decontamination?

h2o2

A somewhat perplexing new study has just been published in the Journal of Hospital Infection comparing the effectiveness of two hydrogen peroxide based automated room decontamination systems: a low-concentration (5%) hydrogen peroxide system (Deprox) and a high-concentration (30%) hydrogen peroxide system (Bioquell).

The study evaluated the impact of the two systems each run in 10 single rooms containing seeded metal discs placed in five locations, with a 6-log load of MRSA, K. pneumoniae, and C. difficile spores. The MRSA and K. pneumoniae were either low soiling (0.03% BSA) or heavy soiling (10% BSA), and the C. difficile spores was either low soiling (0.03% BSA) or in body fluid. In addition, surface samples were taken from 22 surfaces in each room before and after decon using contact plates. The bottom line is that both systems achieved a >5-log reduction on all of the discs (including those with heavy soiling), and there were no real differences in the levels of surface contamination remaining. All this understandably moved the authors to conclude that ‘The starting concentration and mode of delivery of hydrogen peroxide may not improve the efficacy of decontamination in practice.’

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What are we doing to improve hospital room cleaning and disinfection?

I gave a webinar last week for 3M (you can download my slides here) on “Your hospital room can make you sick: How improved cleaning and disinfection can help”. I asked the audience what they were doing to improve cleaning and disinfection, and thought I would share the findings. I don’t know the exact size of the audience (but it’s usually a couple of hundred mainly US based IPC folks), and the audience were allowed to choose any answers that applied to them for the second two questions.

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Endoscope Reprocessing Survey

What-do-you-think

Recent reports of multidrug-resistant infections related to contaminated endoscopes, which have intricate mechanisms and channels that are especially difficult to clean, have raised awareness about the necessity for meticulous reprocessing of all types of endoscopes to prevent the transmission of pathogens to patients.

In response to concerns from various countries about inadequately reprocessed endoscopes and to prevent further transmittal of infections by endoscopes, the ISC Infection Prevention & Control Working Group prioritized this issue in a meeting earlier this year and created a survey on current Endoscope Reprocessing Practices that could be used to compare such practices of institutions around the globe.

We would ask you to share the link to the on-line survey and encourage as many of your colleagues from various health care facilities to complete this. To complete this survey you need to be involved in Endoscope reprocessing activities or know the guidelines and structure of your institutions with regard to Endoscope reprocessing.

Thank you for your participation and for sharing the link!

Link to survey: https://www.surveymonkey.com/r/6ZSGF5L

This checklist was created by the following members of ISC IPC working group. Andreas Voss, Alex Friedrich, Peter Collignon, Moi Lin Ling, Brenda Ang, Wing Hong Seto, Paul Tambyah, Eli Perencevich, Marin Schweizer, Leanne Frazer, Achilleas Gikas, Tom Gottlieb, Joost Hopman, Nikki Kenters, Inge Huijskens, Kalisvar Marimuthu, Rehab El-Sokkary, Yogandree Ramsamy, Margaret Vos, Ermira Tartari, Debkishore Gupta.

Probiotics for environmental cleaning – can’t B. cereus

Schermafbeelding 2015-05-16 om 23.53.46


Vandini et al.
(1) evaluate the effect of a microbial cleaner, containing spores of food grade Bacillus subtilis, Bacillus pumilus and Bacillus megaterium in two Italian and one Belgium hospital.

According to the abstract 20,000 microbiological samples were taken from surfaces, during the 24-week investigation, which would equal approximately 120 samples per day!

While nothing about blinding or block-randomization (or any possible approach that would eliminate bias) was mentioned, it is stated that the cleaning staff was not aware which cleaning product they used. Seen the fact that chlorine based-cleaners were the standard products in the two Italian hospitals, this seems hard to believe. The study period started at different times in the hospitals (but not by design) and in opposite to the abstract for different periods of time, namely 6, 24, and 66 weeks, respectively.

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Asthma and the "Hygiene Hypothesis": Does cleanliness matter? New study says “No”

Guest Blogger Prof Sally Bloomfield (bio below) writes…In proposing the hygiene hypothesis in 1989, Dr David Strachan suggested that lower incidence of early childhood infections could explain the 20th century rise in allergic diseases. This was based on data showing that larger family size appears to protect against hay fever.  Strachan suggested that smaller families provided insufficient infection exposure because of less person to person spread of infections – but also because of “improved household amenities and higher standards of personal cleanliness”.  From this the notion that “we have become too clean for our own good” has arisen.

Most experts now agree that the “hygiene hypothesis” is a misnomer. Although the basic concept is still seen as correct, the link to infectious disease and hygiene is now largely discounted. A number of refinements to the hypothesis offer a more plausible explanation. The Old Friends (OF) Mechanism was proposed by Graham Rook in 2003. He proposed that the required exposures are not childhood diseases such as colds, flu, measles, norovirus, which have evolved only over the last 10,000 years, but the microbes we co-evolved with in hunter-gatherer times when the human immune system was developing. These Old Friends include largely non-harmful organisms such as helminths, commensal microbiota and environmental saprophytes.

Although these microbes are still there, through lifestyle changes we have gradually lost our exposure to them. Improved water, sanitation and food quality, although protective against infections, have also inadvertently reduced exposure to Old Friends which occupy the same habitats. The decline in natural childbirth in favour of caesarean section, and bottle instead of breast feeding is another likely factor. Reduced exposure to our outdoor environment has also occurred – we  now spend up to  80% of our time indoors.  Also, antibiotics may alter our interaction with microbes leading to reduced diversity of human gut microbiota.

Despite a shift in scientific thinking, the so-called “hygiene hypothesis” is still widely accepted in the public domain and  still discussed in terms of concepts such as ‘eat dirt’, ‘too clean is bad’, or ‘sterile homes’.   The lay audience, and even the U.S. FDA attribute the problem to ‘the extremely clean household environments often found in the developed world’.” (See headlines below!)

Bloomfield Public misconceptions re hygiene

What is overlooked is the fact that the relationship between household or personal cleanliness and development of allergies has never been properly investigated. At last – just this week, we have seen publication of the first study to directly evaluate this issue. From the study, Erika von Mutius, a highly respected researcher in this field, concludes – No. “Development of allergies and asthma was not related to cleaning activities”.

Methods: The study involved a birth cohort of 399 participant families recruited in urban and suburban regions of Munich, Germany, between Oct 1999 and Dec 2001. A telephone questionnaire interview comprising 31 questions was carried out to assess cleaning habits and cleaning frequencies in the homes, the use of detergents and the personal cleanliness of the child. In addition, 13 lifestyle factors and home characteristics were obtained from a self-administered questionnaire.  Questions about the child’s health focused on respiratory and allergic problems. Bacterial markers of home cleanliness were assessed in samples of floor and mattress dust.

Results and conclusions: As found by other workers, bacterial exposure in house dust was found to be associated with reduced risk of childhood allergies.  In turn, personal cleanliness, such as washing hands, and home cleanliness were objectively reflected by dust parameters. However, neither personal nor home cleanliness were associated with protection from asthma and allergies (see flow chart, below).

Bloomfield asthma blog flow chart

Note: In this study, cleanliness was substantiated by rather unspecific dust measurements. The findings however suggest that allergy protection operates through as yet unknown exposures, not assessed by unspecific markers. Future studies will require more detailed microbial analysis. Whether these microbes are affected by cleaning remains to be elucidated, but findings with unspecific markers suggest that normal cleaning does not affect permanent microbial colonization of indoor environments.

If, as now seems, allergies are not the price we have to pay for protection from infection, two fundamental questions need to be addressed:

  • “How can we develop an approach to hygiene, which helps to reconnect us with the necessary microbial exposures, whilst also protecting us against infectious diseases? “
  • How do we change public understanding about the difference between “cleanliness” (absence of visible dirt) and “hygiene” (protecting against infectious diseases)?

The answer to the first question is a return to basics, which means promoting “targeted hygiene”.  This means identifying the critical points in the chain of infection transmission and applying effective hygiene procedures at the appropriate times to prevent further spread.  Appropriate times are those associated with activities such as food and water hygiene, respiratory hygiene, toilet hygiene, laundry hygiene and so on.

Dispelling the misconceptions is a real challenge, made more difficult by the fact that people tend to think that hygiene and cleanliness is the same thing (i.e “if it looks clean it must be germ free”). It is possible that this is best done by promoting a more constructive approach i.e . stressing that getting dirty is healthy, but hygiene is vital in the times and places that matter.

Further Reading: Bloomfield SF, Stanwell-Smith R, Rook GA. 2013. The hygiene hypothesis and its implications for home hygiene, lifestyle and public health: summary.

The study can be found at: Am J Respir Crit Care Med. 2015 Jan 13. [Epub ahead of print] Asthma and the Hygiene Hypothesis – Does Cleanliness Matter? Weber J, Illi S, Nowak D, Schierl R, Holst O, von Mutius E, Ege MJ.

Guest blogger bio:

 bloomfield presenting

Dr Sally Bloomfield is an Honorary Professor at the London School of Hygiene and Tropical Medicine. She is also is the Chairman and Member of the Scientific Advisory Board of the International Scientific Forum on Home Hygiene (IFH). Through these roles Professor Bloomfield continues to develop her work in raising awareness of the importance of home hygiene in preventing the transmission of infectious disease, and developing and promoting home hygiene practice based on sound scientific principles. She is also working to develop understanding of “hygiene issues” such as the “hygiene hypothesis” and “antimicrobial resistance”.

Professor Bloomfield’s background is in healthcare and infectious disease. She has a degree in Pharmacy, and PhD in Pharmaceutical Microbiology from the University of Nottingham. Sally was previously a Senior Lecturer in Pharmaceutical Microbiology at Kings College London (1995 – 1997) and a Hygiene Liaison manager at Unilever Research Port Sunlight UK (1997 – 2001). She has published 100 research and review papers on the subject of home hygiene and the action and mode of action role of antimicrobial agents.

What do we mean by ‘cleaning’ and ‘disinfection’?

clean definition 2

We urgently need to decide what we mean when we use the terms “clean” and “cleaning”.

In the last few years, the accumulated microbiological and epidemiological data (and prolonged heated debate) has lead us to conclude that  environmental surfaces need to be considered alongside hands, laundry etc so on, as part of a multibarrier approach to infection prevention and control in healthcare settings, and hygiene at home. Set against this however, our current approach of “what do we do to these surfaces to break the chain of infection transmission?” is both unscientific, and also highly misleading to the people we need to communicate with.  This part of the equation is fast becoming the weak link, preventing us from maximising health benefits from infection prevention and control measures.  This really hit home on reading the different contributions to the excellent 2013 AJIC supplement by Rutala and Webber which, on one hand showed just how much our thinking about environmental surface risks  has developed, but in many papers “environmental cleaning” was used interchangeably with “environmental disinfection” which made it confusing to know what the writer really meant.

From our IFH experience of home hygiene, we know what happens when advising consumers (or equally, hospital cleaning staff) to “clean” a surface e.g. after preparing raw poultry. They will clean until the visible dirt is gone – and we know that this is not necessarily enough.  For the home, we have data showing that after cleaning kitchen surfaces with soap and water following preparation of a chicken (in the UK 60% are contaminated with Campylobacter),  surfaces may LOOK squeaky clean, but the Salmonella or Campylobacter is now spread everywhere (and in numbers up to 103 or more).   We have similar data for surfaces contaminated with norovirus-containing faecal matter from an infected person (for which the infectious dose may be very small).

As a start, we need a term to advise/communicate “this surface needs to be cleaned to a level that breaks the chain of infection” and we currently have NO way to do this.   If we accept that the term “clean” means absence of visible dirt/soil, we need a term to describe “microbiologically safe clean”, not just for consumers or hospital cleaning professionals, but also for communicating with each other as scientists.

There is also another common misconception. Some people work on the basis that “clean” means visibly clean, and “microbiologically safe clean” means a chemical or thermal disinfectant has been used.  But then how can we communicate that hand washing can make hand surfaces microbiologically safe” without need for a disinfectant.  There is a notion that “cleaning” is hygienically inferior to disinfection – but data now shows that the log reduction by handwashing with soap can be equivalent to that achieved by alcohol handrubs if done properly, and you have access to running water.  We put much effort into hand hygiene compliance, but relatively little into stressing that handwashing technique to deliver hands which are “fit for purpose” is equally important.

We need to go back to the simple principles of what we are trying to achieve – namely to break the chain of onwards transmission of pathogens by treating surfaces (hands or environmental) to reduce germs to an “acceptable level” i.e. make a surface “fit for purpose”.  This can be done in 2/3 ways – removing them, inactivation, or a combination of both. For the last 14 years, IFH has successfully used the word “hygienically clean” to mean “microbiolgically safe”, and “hygienic cleaning”  to describe the process to achieve this – which could be soap and water with rinsing – or cleaning disinfection, or a combination of both.

Guest Blogger Bio

SBPHOTO

Dr Sally Bloomfield is an Honorary Professor at the London School of Hygiene and Tropical Medicine. She is also is the Chairman and Member of the Scientific Advisory Board of the International Scientific Forum on Home Hygiene (IFH).  Through these roles Professor Bloomfield continues to develop her work in raising awareness of the importance of home hygiene in preventing the transmission of infectious disease, and developing and promoting home hygiene practice based on sound scientific principles. She is also working to develop understanding of “hygiene issues” such as the “hygiene hypothesis” and “antimicrobial resistance”.

Professor Bloomfield’s background is in healthcare and infectious disease. She has a degree in Pharmacy, and PhD in Pharmaceutical Microbiology from the University of Nottingham. Sally was previously a Senior Lecturer in Pharmaceutical Microbiology at Kings College London (1995 – 1997) and a Hygiene Liaison manager at Unilever Research Port Sunlight UK (1997 – 2001).  She has published 100 research and review papers on the subject of home hygiene and the action and mode of action role of antimicrobial agents.