Emergency! Addressing contamination with antibiotic-resistant bacteria in ambulances

sink The last thing you need if you require the services of an emergency ambulance is exposure to antibiotic-resistant bacteria from contaminated surfaces. A recent US study suggests that this is commonplace, finding MRSA environmental contamination in every single emergency ambulance tested! These findings reinforce the need for thorough cleaning and disinfection of emergency ambulances.

The study team sampled oxygen cylinders and regulators in 9 emergency ambulances, and 70 oxygen cylinders in an off-site storage facility for MRSA. Amazingly, all 9 emergency ambulances were found to be contaminated with MRSA, as were 67/70 (96%) of oxygen cylinders in the storage area. MRSA wasn’t found on most of the surfaces sampled in the ambulance.

The findings are consistent with previous studies, which have also found contamination of ambulances. Furthermore, previous studies have also shown that existing methods for cleaning and disinfecting ambulances are not sufficient to tackle contamination with clinically-relevant organisms. These studies suggest that more needs to be done to ensure that ambulances don’t become a source for the acquisition of MRSA and other antibiotic-resistant bacteria.

The disinfection of ambulances is challenging. They have multiple touch points, a risk of heavy levels of organic soiling, the need for rapid turnaround, and a requirement for environmental hygiene procedures that can be applied quickly and effectively on the road. Disinfectant wipes can help in developing effective environmental hygiene protocols for ambulances.

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Sink drains as a risk for CPE

sink
There is increasing evidence that sink drains can be contaminated with CPE and that this environmental contamination can find its way onto patients. A new study from the US found that contamination of sink drains with CPE and with carbapenemases was commonplace, and that proximity to toilets was an important predictor of drain contamination.

The study was performed in a 26-bed medical ICU within a 600-bed hospital in Milwaukee, Wisconsin. Each room has two sinks and one toilet – one of the sinks is closer to the toilet than the . Each sink drain was sampled using swabs. The KPC carbapenemase gene was detected by direct PCR from more than half of the sinks (54% of 46 sinks), and CPE was cultured from 10% of 40 sinks. The sinks that were closest to the toilet were significantly more likely to be contaminated with the KPC carbapenemase (87% of 23 sinks near toilets vs. 22% of 23 sinks at room entry). The CPE that were cultured from the sinks were a mixture of Enterobacteriacae that are often implicated in human colonisation (such as Klebsiella pneumoniae) and ‘weird and wonderful’ Enterobacteriaceae from the environment.

In this study, the reason why sinks closer to toilets were more contaminated with carbapenemases is not clear. However, it seems likely that differences in the uses of the two sinks in the room explains the difference. The sink at the point of entry into the room would most likely be used by staff either before or after patient care. However, the sink by the toilet would most likely be used by patients following toilet use, and by staff during patient care; and these activities carry a higher risk of contamination being transferred to the sink.

The study underlines the need to improve the management of sinks to ensure that they do not become contaminated with CPE, because we know from other studies that sinks contaminated with CPE are a risk to patients.

 

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Putting disinfectants through their paces using Candida auris dry surface biofilm efficacy testing

Candida auris
Candida auris is a high-profile emerging pathogen, which has caused large outbreaks both in the UK and elsewhere. C. auris can causes widespread environmental contamination, and isn’t susceptible to all disinfectants. This new study from Cardiff University extends previous findings by developing a dry surface biofilm efficacy testing model for C. auris. Worryingly, half of the disinfectants tested barely touched the C. auris in the DSB, suggesting that more powerful disinfectants (such as peracetic acid and sodium hypochlorite) should be selected for dealing with C. auris.

Previous studies have shown that a range of disinfectants are effective against C. auris when using conventional suspension testing methodology. However, we know from other studies that the presence of dry surface biofilm (DSB) can reduce the susceptibility of micro-organisms to disinfectants considerably. DSB occur when bacteria and other microbes become attached to surfaces and encased in a protective ‘slime’ layer: this can reduce their susceptibility to disinfectants by 10 to 1000-fold. Therefore, a team at Cardiff University developed a DSB model for C. auris disinfectant testing. 12 commercially-available wipe based disinfectants were tested. Concerning, 50% of the products tested failed to decrease C. auris viability, 58% failed to prevent its transferability, and 75% did not delay biofilm regrowth. Wipes that were effective in reducing C. auris viability and transferability included Clinell’s Universal Wipes, and Clinell’s Sporicidal Wipes (which are based on peracetic acid). Clinell’s Sporicidal Wipes were most effective at preventing re-growth of the biofilm.

This research reinforces that microbes in DSB are considerably less susceptible to disinfectants than microbes in suspension. Caution should be exercised in choosing the appropriate disinfectants for dealing with surfaces potentially contaminated with C. auris, with decisions informed by studies using DSB-based testing methods.

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Wiping out MRSA using Clinell “green” wipes

A study just published by scientists from University Hospital Birmingham evaluated the impact of introducing the one-step Clinell Universal Wipes (which both clean and disinfect) to replace a two-step detergent wipe cleaning followed by alcohol wipe disinfection for nurse-led cleaning tasks. The change in disinfection approach was associated with a significant 55% reduction in the rate of MRSA acquisition.

Despite the widespread use of disinfectant wipes in hospitals, there are few studies with a clinical outcome showing that they reduce transmission of pathogens than can cause HCAI. The study focused on cleaning of ward areas and patient equipment performed by nursing staff (as opposed to cleaning of the general healthcare environment by cleaners). In the baseline period of the study, from April 2013 to April 2016, a two-step system was used by nurses for these tasks. Firstly, a detergent wipe was used to clean the surface following by disinfection using an alcohol wipe. During the intervention phase of the study, from May 2016 to December 2017, Clinell Universal wipes were used as single-step cleaning and disinfection process. The switch to Universal wipes was accompanied by an educational package spanning one month, to ensure that staff understood the switch from a two-step to a one-step process correctly.

Following the introduction of the Universal wipes, the number of MRSA acquisitions decreased from 20.7 to 9.4 per 100,000 patient bed days (p <0.005). A Poisson regression model found that the average rate of MRSA acquisition per 100,000 patient bed days reduced by 6.3% per month after the introduction of the new wipes. Importantly, compliance with MRSA screening was high (>90%) and audits revealed no significant changes in hand hygiene compliance, the appropriate use of personal protective equipment (PPE), or environmental cleanliness during the study. The impact of switching to Universal wipes was all the more impressive because the reduction was achieved despite the cessation of universal decolonisation using chlorhexidine during the baseline period.

This study is important because it’s one of the first to demonstrate that switching to Universal wipes results in a significant reduction in the acquisition of MRSA. The findings underline the importance of cleaning and disinfection tasks performed by nursing staff, because by improving the efficacy of these tasks without intervening to improve general cleaning, a 55% reduction in MRSA acquisition was achieved. The study didn’t evaluate the time that it took nursing staff to perform these cleaning and disinfection tasks in the baseline period or during the intervention, but it seems likely that the single-step process would have been quicker and less resource- intensive than the two-step process. It seems likely that these findings would be transferable to other organisms that survive for extend periods in the healthcare environment such as CPE, VRE, and Acinetobacter species.

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Updates from the Healthcare Infection Society’s 2018 conference

HIS_2018
We enjoyed the recent Healthcare Infection Society’s 2018 conference in Liverpool, and thought we’d share a few highlights. You can view all of the submitted abstracts here and the invited abstracts here. The role of the environment in the transmission of HCAI was a strong theme throughout the conference, with key speakers discussing the relative importance of contaminated surfaces and water in transmission compared with other routes. There was even an entire submitted oral presentation session on water-related transmission of Gram-negative bacteria! Some highlights include:

  • An intervention study from University Hospital Birmingham evaluated the impact of introducing the one-step Clinell Universal Wipes (which both clean and disinfect) to replace a two-step detergent wipe cleaning followed by alcohol wipe disinfection for nurse-led cleaning tasks. The change in disinfection approach was associated with a significant 55% reduction in the rate of MRSA acquisition (from 20.7 to 9.4 per 100,000 patient bed days; p <0.005).
  • A collaboration between Chinese and British scientists has evaluated the residual impact of the disinfectant formulation extracted from Clinell Universal wipes (abstract #103). The quaternary ammonium compound based disinfectant extract from the wipes achieved a >6 log reduction on coli and S. aureus dried onto metal and plastic surfaces for at least 24 hours, whereas chlorine exhibited no residual activity. This is one of the first studies to quantify the residual impact of a QAC based disinfectant. These findings are supported by a recent study which reported that Clinell Universal Wipes exhibited residual antimicrobial activity for >6 hours in a clinical setting.
  • Work from the University of Huddersfield investigated the effectiveness of disinfectants for tackling surfaces contaminated with Candida auris (abstract #241). Clinell Universal wipes were pitted against other disinfectants (PHMB, benzalkonium chloride (BZK), and DDAC) in laboratory tests. The Clinell wipes achieved a >4-log reduction against all of the strains of auris tested, whereas the other disinfectants were less effective. This highlights the importance of disinfectant formulation, illustrating that the Clinell formulation for Universal Wipes extracts the best performance from its constituent chemicals.
  • A team from University Hospitals Birmingham investigated the environmental impact of introducing for terminal disinfection in a haematology ward. 15 rooms were tested for surface contamination with the mean cfu being 40 cfu prior to cleaning, 16 cfu after cleaning, and 0.3 cfu after cleaning. UVC offered a rapid and efficient way to improve the standards of environmental hygiene at the time of patient discharge.
  • An academic collaboration between Cardiff University and Gama reports the findings of research work into methods to tackle dry surface biofilms (abstract #86). The efficacy of 12 biocides and hydrogen peroxide vapour (HPV) was evaluated. Peracetic acid was the only biocide able to achieve a >6-log reduction on the biofilms, and 10/13 biocides failed to prevent transfer of bacteria from the biofilms following exposure. Novel approaches to disinfection are necessary to tackle dry surface biofilms effectively.
  • Research work performed by scientists from UCLH and Great Ormond Street found that surface contamination was correlated with height in the room, with lower surfaces tending to be more heavily contaminated (abstract #182). They also performed extensive observation of cleaning practices, finding that cleaning methods were inconsistent between staff groups, and that confusion of cleaning roles was evident, illustrating the need for clear delineation of cleaning responsibilities between different staff groups. The same research group also performed a systematic review of surface sampling methods (abstract #216). The literature provided incomparable and contradictory findings, highlighting the need for carefully controlled studies to inform environmental sampling methods.
  • A study from researchers in Sheffield and Bath evaluated the acceptability of three difference approaches to antibacterial skin washing to reduce the risk of infections associated with peripheral cannulae (abstract #158). Interestingly, there were differences in staff and patient preferences (with patients preferring Clinell wipes). However, patient and staff preferences need to be balanced against cost and effectiveness when choosing the optimal antibacterial skin washing approach.
  • The conference featured a debate on the relative importance of antibiotic use and the acquisition of difficile spores in driving C. difficile infection. Prof Mark Wilcox argued that antibiotics are the most important driver, and Dr Jon Otter argued that the acquisition of C. difficile spores is more important. At the start of the debate, two thirds of the audience agreed with Mark, but after hearing all the arguments, two thirds of the audience agreed with Jon! This underlines the importance of interrupting the spread of C. difficile spores, which requires a focus on improving environmental hygiene!
  • The conference also featured a debate on decontamination and environment: high vs low technology. Dr Curtis Donskey argued for high technologies, and Prof Stephanie Dancer argued that low technologies will always be required. Dr Donskey stressed the importance of manual cleaning before the deployment of automated systems, arguing that the speed, efficacy and non-corrosive nature of such systems made them an attractive adjunct to manual cleaning. Dr Donskey also discussed the results from the BETR-D study and evidence for automated systems in reducing rates of healthcare associated infections (HAIs), when compared to traditional methods. Prof Dancer argued that we can use all the ‘hot air’ high technologies available but they can’t physically remove dirt and that cleaning is essential with one wipe, one site, one direction and elbow grease. Prof Dancer presented evidence on numerous ‘cleaning’ studies and used the latest evidence from the REACH cleaning initiative study to show the impact on MRSA and VRE rates. At the end of the debate Dancer ‘wiped’ the smile of Donskey’s face, because the audience voted for low technology! If you’d like to hear more about any of the above, please get in touch.

     

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