Well, they certainly do in the National Health Service in England!
There has been significant coverage recently of some new research suggesting “Wet wipes could be spreading bacteria in homes and hospitals” (Daily Telegraph), “Hospital bugs ‘spread by use of wet wipes to clean wards’ according to first study of its kind” (Daily Fail) and “ ” (Daily Express).
But just for once the headlines were pretty accurate.
The reporting under those headlines was long on sensation and short on facts (so no great surprises there, then) and – naturally – none of the journalists bothered to read the source material preferring to simply regurgitate the press release adding whatever fact-free spin suited their purposes.
So, dear readers, I have picked over the detail in the original paper. Which is a good study by a highly-respected team published in a high-impact journal. Let’s start with what the paper actually said:
- Detergent wipes widely used in the NHS (and elsewhere) are rubbish at removing dangerous microorganisms from surfaces
- They are rather good at spreading microorganisms about the place to cause trouble elsewhere, however.
Let’s quickly remind ourselves how detergent wipes are claimed to work:
- To first ensure the efficient removal of bioburden and microorganisms from a surface
- Secondly, to retain the captured microorganisms on the wipe, thus preventing cross-contamination by the transfer of pathogens.
This is important because the majority of infection control policies over here are based on the NHS Hygiene Code and parrot its advocacy of detergent and water (or microfibre cloth and plain water) for cleaning soiled / contaminated surfaces, because disinfectants should not be routinely used. Yes, you did read that correctly. Disinfectants should not be routinely used.
Let’s look at the logic of that. As we rapidly approach a post-antibiotic era it’s no longer as simple as a clinician prescribing your aged mother an antimicrobial drug when the poor, senile old bat picks up an entirely preventable infection from a filthy ward or – more likely – no-one washing their damn hands.
Quite simply, we can’t rely on a convenient antibiotic being instantly available any more to deal with any given infection. So we need to do all we can to prevent infections being passed on. Like cleaning hospitals with stuff that kills bugs stone dead instantly rather than spreading them around the place.
But never let it be said the NHS does things by halves:
“Let’s make sure when the ward gets cleaned every other month, we use something that doesn’t kill bugs. Because bugs develop resistance to antibiotics. And lab experiments have shown if we try really hard we can elicit resistance to low-concentration on-skin biocides like Triclosan as well.
Therefore bugs will become resistant to cleaning chemicals like caustic soda too. Because even though that kills a bug stone dead by turning its cell wall to soap, bacteria can still develop resistance to. Because dead things mutate, innit.”
This Food Babe-like antipathy to disinfectants is a principal reason for the increasing use of detergent wipes for environmental cleaning in health and social care. They are seen as a convenient, ready to-use, disposable solution and a key intervention in infection prevention and control. And, of course, they work. Because the guidelines say detergent good, disinfectant bad.
And despite infection prevention and control not being the natural home of evidence-based practice (because outbreaks don’t lend themselves to double-blind, placebo-controlled randomised trials, the guidance must be evidence-based, right?
Why the Current Advice Is So Dense Light Bends Around It
The ability of microorganisms such as MRSA, vancomycin-resistant enterococci, Clostridium difficile and many significant others to persist on inanimate surfaces for prolonged periods is well recognized. And I see paper after paper reporting study after study showing common healthcare-associated pathogens repeatedly being isolated from ‘high-touch’ points in close proximity to patients.
While proper hand hygiene will always be the key intervention in effective infection prevention and control, the body of evidence showing the significance of environmental contamination in the transmission of clinically-relevant pathogens grows constantly – yet the advice is still that disinfectants or combined sanitiser / detergent products should not be used and general-purpose detergents or detergent wipes are ‘best practice’.
This advice has always flown in the face of the most basic tenets of microbiology and is a classic example of the informal logical fallacy of argumentum ad ignorantum – essentially asserting a proposition (in this case that detergents are perfectly adequate) must be true because no-one has proved otherwise.
The paper recently published in the American Journal of Infection Control Pathogen transfer and high variability in pathogen removal by detergent wipes hasn’t just driven a rather large coach and horses through the wipe nonsense it also suggests – shock! – that perhaps it might be an idea to use products actually kill bugs, given detergent wipes just send them on a nice little holiday to somewhere else in the hospital.
And this is no half-arsed study in some fly-by-night publication; AJIC is what’s known in the biz as a ‘high-impact’ (i.e. high-quality, highly respected) academic journal, as is the leader of the group who conducted the study, Jean-Yves Maillard. He and his group are highly regarded in infection control research so if Jean-Yves says ‘detergent wipes are bad‘ people will listen.
Perhaps even the NHS…
What This Study Did
They took a range of detergent wipes currently in use by the NHS and tested how good they were at removing three different bugs from a stainless steel surface. They used staph, C. diff spores and a lesser-known HCAI called Acinetobacter baumannii as a good representative group. They were looking at:
- How good each wipe was at physically removing bugs from surfaces
- Whether they transferred bugs between three consecutive surfaces
Their experimental design was elegant and technique spot-on – as one would expect from the Maillard group. They dried out carefully-controlled amounts of three types of bug onto metal discs then ran them through a marvellous piece of kit called a ‘Wiperator’.
This ensured the wiping action was precisely the same no matter which wipe was being tested so performance could be measured in a repeatable way.
What They Found
To summarise the results – which varied across a broad range – based on a 10-second automated ‘wipe’ (which if extrapolated to ‘real-world’ hospital cleaning is several short eternities):
- All the wipes failed to completely remove bugs (esp staph and C. diff)
- In terms of reduction they got 3 logs for Acinetobacter and 1 for the others.
This is hardly a reduction at all in meaningful terms. On the transfer front all but one wipe transferred bugs to subsequently-wiped surfaces.
Remember: detergent wipes are marketed on the basis they physically remove soiling and microorganisms and keep them stuck on the wipe. Oops.
What This Means
Quite simply, detergent wipes are rubbish at removing microorganisms but pretty good at spreading them around.
And don’t forget wipes need to be used properly to prevent cross-contamination: one wipe, one surface, one direction. How often do you see wipes being used that way in a hospital?
What They Said
The rise in healthcare-associated infections has placed a greater emphasis on cleaning and disinfection practices. The majority of policies advocate using detergent-based products for routine cleaning, with detergent wipes increasingly being used; however, there is no information about their ability to remove and subsequently transfer pathogens in practice.
Or ‘everyone says wipes are good, detergent good, disinfectants bad but no one has ever bothered testing this‘. Until now.
After the tests they concluded that:
Detergent-based wipe products have 2 major drawbacks: their variability in removing microbial bioburden from inanimate surfaces and a propensity to transfer pathogens between surfaces.
The use of additional complementary measures such as combined detergent / disinfectant-based products and/or antimicrobial surfaces need to be considered for appropriate infection control and prevention.
Which is pretty much what we’ve said all along! And just in case anyone is confused they added:
Because detergent cleaning is advocated in many national guidance documents, it is imperative that such recommendations and guidance take into account the wipe limitations found in this study.
The issue of potential transfer on to multiple surfaces needs to be addressed to avoid the potential spread of microbial pathogens.
This is about as direct as it gets; scientists have a particular way of communicating and are not given to this sort of language as a rule.
What They Missed
In the discussion of the results, the authors speculate on the possible reasons for the variation in performance between the different wipes they tested, all impregnated with similar “nonionic surfactants, preservatives, and perfume; therefore they would be expected to perform on par with each other”. They ask if the quality of the raw materials and wipe material, the liquid to wipe ratio or packaging of the product might influence this.
They are entirely correct that the formulation of the detergent used and its compatibility with the nonwoven material may well influence the efficacy of a product – you can’t just take a really good liquid cleaner / sanitiser formulation and chuck it on a wipe.
Different sorts of wipe material, surface area at a microscopic level, what sorts of charges you find on different fibres all can render a really good formulation totally ineffective in a heartbeat. But wipe manufacturers know this.
But they’ve missed a really, really important point. The wipes are based on non-ionic surfactants.
Bear with me here. Detergents and soaps are surfactants, short for ‘surface-active agents’. Only difference is soaps are prepared from animal or vegetable fats and oils (you mix them with an alkali to turn them into soap) and detergents are made from petrochemicals and other stuff. And soaps perform less well the harder the water is, this doesn’t affect detergents.
Anyway, surfactant molecules have a hydrophilic – or ‘water-loving’ – end and a hydrophobic end that hates water. So if you put a surfactant in a drop of water, the water-hating bits stick out of the top and break the surface tension. So beads of water on a surface will sheet out and the beads disappear. (Water has serious surface tension – which is why it beads on a surface, gets drawn against gravity up capillaries and insects can walk on it).
Add a fat and it gets more interesting. The water-hating end of each surfactant molecule sticks into fats, the water-loving end wants to stay in the water and away from the fat – and this is how surfactants pull apart greasy soiling. And don’t forget bacterial cell membranes are made of fat.
There are four basic types of surfactant, depending on the electric charge of the head of the molecule: anionic surfactants (negative charge), cationic surfactants (positive charge), nonionics (no charge) and zwitterionic (aka amphoteric) surfactants which can swing either way depending on how they feel.
Here’s why surfactant choice is really important (note that it wasn’t mentioned in the paper could be for all manner of reasons).
Bacteria are negatively charged.
This is due to a number of factors depending on the type of bacteria – teichoic acids in the Gram-positive cell wall carry a negative charge because of the phosphates in their structure. Gram-negatives have an outer covering of phospholipids and lipopolysaccharide which confer a strongly negative charge.
Those factors, other phosphorylated sugars and respiration kicking out electrons all over the place all mean a negative charge. Which is why cationic surfactants (positive charge) are really good at sticking to bacteria and usually royally screwing them up – most cationic surfactants have powerful antibacterial as well as surfactant activity.
Which is why when you use cationics in a wipe bacteria stick to them like shit to a blanket and are rapidly kebabbed, rendering them what we microbiologists call “proper fucked“.
What Happens Now?
So, non-ionic detergent wipes are rubbish at picking up and hanging on to bacteria. Water is wet. Fire is hot. Bears defecate in woodland areas. That bacteria are negatively charged may well play a part in this – but that’s my opinion, not something in the paper and my view may well not be shared by the authors, their successors and assigns, responsible adults anywhere, yo’ mama and certainly not the NHS or those nice folks at PHE Colindale.
What is true is wipes impregnated with a cationic (positively charged) surfactant do not suffer this problem and work very well – but if you put a cationic on a wipe it won’t just clean effectively, it will kill bacteria – and so fall foul of the Hygiene Code.
And then where would we be?
We might reduce the one million NHS bed nights per year taken up by patients with infections they picked up in hospital (the equivalent of 2,700 hospital beds every day) or reduce the number of deaths caused by preventable infections. Or save the £10m per annum the NHS pays out in compensation in addition to the cost of all those hospital stays. And let’s not forget the human cost of all those preventable infections too.
It would seem to be a no-brainer that the NHS do as suggested – follow the recommendations of some of the most respected people in the business and re-evaluate its position. A position which is, frankly, barking mad to any sane observer or even dangerous seditionists like me.
But flogging these wipes to the NHS is a huge industry and if you want to elicit a sea change in an organisation like the NHS that is – paradoxically – incredibly monolithic and incredibly tribal at the same time you probably have more chance of taking a shit in the Queen’s handbag.
Another embarrassing and inconvenient fact is that hospital-acquired (sorry, we’re supposed to call them ‘healthcare-associated’ now) infection rates are far lower in countries such as Iran, Latvia, Mongolia or Ghana than in NHS hospitals.
If the WHO publishing the epidemiological data that backs up that last statement didn’t shame the NHS into change I’m not convinced slam-dunk scientific data will. And we can already see the nay-sayers lining their ducks up:
This research didn’t take place in a clinical setting
No, it took place in a lab where you can control all the other variables and confounding factors so the data you collect is actually meaningful.
They didn’t use the wiping protocols used in hospitals
No, a machine did it so every wiping process was identical and reproducible. Again, this is about collecting robust data. And if you’ve observed how wipes are used by most staff in hospitals (as I have) you will know that despite what the protocols might say the real-life practice is about as much use as tits on a nun.
This is not relevant
One could argue that this is only one study. Or only stainless steel surfaces were used. Or a greater range of bugs need to be tested. Or that they didn’t prove the numbers of bugs not removed or the quantity transferred could actually cause or significantly raise the risk of infection.
Granted, like all science this needs to be (and will be) replicated by others. But none of the above arguments sink the findings of this paper and are what’s known as ‘special pleading’ – which is a polite scientific term for ‘clutching at straws’.
The conclusions are biased
It is noteworthy that this research wasn’t just academically rigorous it was university-funded and conducted. That it was was not financed by Big Wipe is important: it has been shown that academic research funded by companies does tend to show a slight positive bias. This is almost always unintentional, is a known bias but doesn’t apply here.
Incidentally, this is different to research conducted by companies – where experimental design tends towards “how can we prove our widget is best” whereas a scientist has a different starting point: “I wonder how I can find out which of these widgets is best?” – it’s a big difference.
The Bottom Line
What one cannot escape is this is a well-designed study, conducted by a highly-respected group with no conflicts of interest and their principal findings are simple – detergent wipes are largely ineffective at removing potentially life-threatening microorganisms from surfaces but are pretty damn good at moving potentially life-threatening microorganisms from one surface to another.
This doesn’t just show detergent wipes have no role to play in infection control; as the authors note it’s time to re-evaluate whether using cleaning products that actually kill bugs might be appropriate (and I’m sure you can guess my views on that).
This may seem simple but it’s not. There’s a whole other post brewing about evidence-based practice – which seems like a Good Thing until you get basic scientific plausibility sacrificed on the EBP altar as soon as some shitty study is published.
Or, as in this case, the argument from ignorance prevails – this is from National Evidence-Based Guidelines for Preventing Healthcare-Associated Infections in NHS Hospitals in England:
Disinfectants have been recommended for cleaning the hospital environment, however, a systematic review failed to confirm a link between disinfection and the prevention of HCAI, although contamination of detergent and inadequate disinfection strength could have been an important confounder.
Whilst subsequent studies may have demonstrated a link between disinfection and reduced environmental contamination, and sometimes the acquisition of HCAI, the study designs are weak with no control groups or randomisation of intervention, and /or the introduction of multiple interventions at the same time.
This makes it difficult to draw definitive conclusions about the specific effect of disinfection or cleaning.
How the fuckitty fuckitty fuck are you supposed to conduct a randomised, controlled trial of an infection control intervention during an outbreak?
And even if you could design one how the fuck would it ever pass ethical review? See what I mean about basic scientific plausibility or just basic common sense being ignored because you can’t run a fucking RCT? Let’s try to predict the Dept of Health’s position:
The Maillard group study has no relevance until it has been replicated and demonstrated to be relevant to all organisms on all surfaces in a series of double-blind, placebo controlled RCTs…
Cock Womble-ry of such biblical proportions isn’t the only reason I am so pessimistic. The NHS wastes millions each year on expensive, worthless placebos like ‘integrative’ medicine and three ‘homeopathic hospitals’ – or to give them their proper title, expensive white elephants ministering to hypochondriac middle-class hippies.
My challenge is I just can’t see any change happening in an organisation led by a health secretary who believes interventions such as homeopathy – entirely based on magic rather than science – is a legitimate use of the public purse.
Which – if you think about it – is a bit like having a transport secretary that believes in broomsticks…