Tuesday June 9 2015
Infection control in hospital is vital for patient safety
"A new study finds that detergent wipes are spreading bugs in hospitals," The Daily Telegraph reports. This isn't strictly true, as the study didn't do any tests in hospitals. But through laboratory experiments, researchers found seven commonly used brands of wet wipe could transfer bacteria from one surface to another.
Researchers tested seven detergent cleaning wipes they say are used in UK hospitals. They looked at three common causes of hospital-acquired infection: Staphylococcus aureus, a common cause of skin infections; Clostridium difficile, which can upset the digestive system; and Acinetobacter baumannii, which is usually harmless for most people, but can be very dangerous for people with a weakened immune system.
They found using the same wipe on different surfaces seemed to help these three germs spread. The study also found large variation in the ability of the different types of wipes to kill these three germs.
The authors mention a "one wipe, one surface, one direction approach," but they suspect people use the wipes on multiple surfaces in reality. As this was an experimental study, we do not know whether the use of wipes in this way would have a real-world impact and, if so, what that impact would be. We also don't know how wipes compare with other cleaning methods.
Still, this study does reinforce the importance of infection control in hospital, something that staff, visitors and patients can help to maintain by taking simple steps such as washing their hands frequently.
Where did the story come from?
The study was carried out by researchers from Cardiff University and was funded by the university. It was published in the American Journal of Infection Control, a peer-reviewed journal.
Generally, the UK media reported the story accurately given the information they were presented with. However, an inconsistency did creep in at the research reporting stage and was replicated in most of the subsequent press coverage.
The researchers made the statement: "All the wipes repeatedly transferred large number of S. aureus on to three consecutive surfaces except wipe G, for which transfer of bacteria was below the limit of detection for this test."
But in the conclusion, this was summarised to: "All of the wipes repeatedly transferred bacteria and spores on to multiple surfaces". This shortened version in the conclusion made it into most of the media coverage.
What kind of research was this?
This study looked at the effectiveness of detergent cleaning wipes for cleaning germs.
The researchers say the majority of current UK infection control policies advocate the use of detergent and water, or microfibre and water, for cleaning soiled or contaminated surfaces, adding that detergent wipes (wet wipes) are increasingly being used.
However, the team claim there is no good information about the ability of wet wipes to remove disease-causing microbes, or whether they could subsequently transfer microbes from one surface to another.
What did the research involve?
The study picked seven detergent wipes currently used in healthcare facilities in the UK, and tested how good they were at killing three microbes from a stainless steel surface.
The microbes of choice were Staphylococcus aureus, Acinetobacter baumannii, and Clostridium difficile, representing common – and sometimes lethal – sources of hospital-acquired infections.
The wipes were tested to see how good they were at:
- removing micro-organisms from the surfaces
- preventing bacteria transfer when the same wipe was used to clean three consecutive surfaces
After using a 10-second "standard wiping protocol", the researchers measured the ability of the wipes to kill bacteria and spores using a standardised European method of assessment for chemical disinfectants.
Wiping experiments were independently repeated three times to get an average, and were analysed using appropriate methods.
What were the basic results?
The detergent wipes tested in this study showed big differences in their ability to remove the three germs from surfaces after a 10-second wipe.
They performed quite differently depending on the germs tested. Broadly speaking, the wipes were able to remove a lot of Acinetobacter baumannii, but performed worse for Staphylococcus aureus and Clostridium difficile spores.
Almost all wipes also repeatedly transferred significant amounts of bacteria or spores over three consecutive surfaces, except for one, which registered no transfer.
Even then, the research team say the percentage of total micro-organisms transferred from the wipes after wiping was low for a number of wipes.
How did the researchers interpret the results?
The team said: "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 research suggests detergent cleaning wipes used in UK hospitals and the home show large variability in their ability to kill three selected microbes, including Staphylococcus aureus and Clostridium difficile.
Researchers tested seven commonly used wipes and found they varied a lot in their ability to kill the bugs. More worryingly, it looked like the wipes were picking up the germs rather than killing them – in almost all the wipes tested, the bugs were spread if they were used on a different surface.
The implication of this is that wipes shouldn't be used on consecutive surfaces. The authors mention that "a one wipe, one surface, one direction approach" is recommended, but they suspect people use them on multiple surfaces in reality.
This is a single study, so we don't know for sure that its results are reliable. There were some inaccuracies – for example, in how the study estimated the starting level of contamination in the tests.
The best way to find out would be to repeat the experiments, ideally using wiping protocols used in hospitals, and on the most common surfaces. Only stainless steel surfaces were tested here. Extending the number of bugs tested would also improve the study, as only three specific types were tested.
It also wasn't clear whether the amount of contamination after wiping was enough to cause or significantly raise the risk of infection. We don't know how often the wipes are used in hospital, or whether they are used alongside other more effective cleaning methods.
Hospital infection can be life threatening, so ensuring cleaning practices are evidence-based and effective is likely to be a priority. This research highlights how some wipes may not be as effective for specific germs on specific surfaces as we might assume.
Hospital cleaning protocols are continuously being assessed and refined, so this study will undoubtedly add to this process.