Candida auris is an important emerging pathogen, which caused a large outbreak in a London hospital and has been reported from around the world. It shows a high level of resistance to antibiotics and appears to spread rapidly in hospitals. A new study evaluates the efficacy of various antiseptics and disinfectants that could support the prevention and control of C. auris.
The authors evaluates the efficacy of two commonly used disinfectants (chlorine and hydrogen peroxide vapour) and antiseptics (chlorhexidine gluconate and povidone iodine) against 34 Candida species, including 28 C. auris isolates. HPV was tested in the gas phase, whereas two chlorine-based products and the antiseptics (chlorhexidine gluconate and povidone iodine) were tested in the liquid phase, to represent the uses of these disinfectants / antiseptics in practice. Also, a novel methodology was used to test the efficacy of two brands of pre-impregnated 2% chlorhexidine gluconate washcloths (including the Clinell Wash Cloths). These were tested by adding a cut piece of the wash cloths onto the surface of an agar plate and performing measuring the diameter of the zone of clearing.
Gas phase HPV inactivated most of the C. auris isolates tested, and was considered to be 96.6%-100% effective. This suggests that longer HPV exposure may be necessary to fully inactive C. auris. All Candida species were inactivated fully by in-use concentrations of the disinfectants and antiseptics tested. In the experimental procedure to test the antimicrobial activity of the pre-impregnated wash cloths, the C. auris isolates tested appeared to be less susceptible than the non-C. auris isolates tested, suggesting that C. auris is less susceptible to chlorhexidine than non-C. auris isolates, as seems to be the case for most other disinfectants and antiseptics. Both types of pre-impregnated wash cloths performed similarly.
These results suggest that antiseptics such as chlorhexidine gluconate and povidone iodine, and disinfectants such as chlorine and hydrogen peroxide vapour are suitable for preventing the transmission of C. auris, and that current in-use concentrations are adequate.
A lab-based study using healthy volunteers has demonstrated that antimicrobial-impregnated hand wipes can do as well – if not better – than soap and water for hand hygiene. These findings provide more support for the idea that hand wipes could be a useful innovation in improving patient hand hygiene.
The study aimed to evaluate the use of an antimicrobial-impregnated wipe designed for hand hygiene against soap and water. The hands of 20 healthy volunteers were contaminated with a solution containing E. coli. The volunteers’ hands were then allowed to air-dry before undergoing hand hygiene using soap and water, a control wipe (without antimicrobial agents) and a test wipe (with antimicrobial agents). The key result is that the antimicrobial-hand wipe was not inferior to the hand washing procedure using soap and water (3.7 log reduction for the hand wipe vs. 3.5 log reduction for the soap and water). The hand wipe without antimicrobial agents was inferior to hand washing using soap and water (2.5 log reduction for the hand wipe without antimicrobial agents vs. 3.5 log reduction for the soap and water).
The team also tested the antimicrobial activity of the “juice” squeezed from the antimicrobial-impregnated hand wipe. These tests showed that the antimicrobial achieved a >4 log reduction against all organisms tested after a 60 second contact time, and a >4-log reduction against all organisms except Candida albicans after a 30 second contact time. It is important to note that these suspension tests don’t account for the physical removal of micro-organisms from hands.
There are no standards available for testing the effectiveness of wipes designed for hand hygiene use, so the methods used in this study ought to serve as a model for future experiments and testing standards.
This study demonstrates the exciting potential for antimicrobial-impregnated hand wipes to be used to improve hand hygiene for patients, who may not be able to access soap and water. These wipes may also have useful applications for hospital staff where access to soap and water is limited or when alcohol gel is not appropriate due to soiling.
A US before-after study evaluated the impact of introducing chlorhexidine daily bathing in an ICU setting. In line with other studies, the rate of acquisition of key hospital pathogens, including VRE, MRSA, and antibiotic-resistant Gram-negative bacteria reduced in response to the introduction of chlorhexidine, and remained lower over time.
The 8 month before-after study was performed in a 24 bed ICU in the US, with a 1 month pre-intervention period and an 8-month intervention period. Admission and discharge screening was performed for important hospital pathogens (VRE, MRSA, and antibiotic-resistant Gram-negative bacteria). There was a significant reduction in the prevalence and incidence of both VRE and antibiotic-resistant Gram-negative bacteria associated with the introduction of chlorhexidine daily bathing. Whilst this reduction was sustained throughout the intervention phase, it did not trend down further; the authors suggest that focus on implementing daily chlorhexidine bathing waned after initial enthusiasm. This supports the need for continuous education to ensure compliance with best practice infection prevention interventions.
Whilst there was no randomisation or concurrent control group, this study reinforces that chlorhexidine bathing results in a clear and sustained reduction in the transmission of key hospital pathogens in the ICU setting.
A US study has found that around 15% of patients with C. difficile infection have C. difficile contaminated hands, and that removing these spores from patients’ hands is challenging.
The study was performed in a 500-bed US hospital. Around 50 patients with C. difficile infection were enrolled in the study, and randomised to either hand hygiene using either alcohol-based hand rub (ABHR) or hand washing using soap and water. The hands of patients were sampled both before and after hand hygiene. 7 (15%) of the patients had contamination with C. difficile before hand hygiene; C. difficile persisted despite hand hygiene on the hands of all three patients in the ABHR arm, and on 2/4 patients in the soap and water arm. It is important to note that patients with limited mobility (and so had to wash their hands at the bedside rather than at the sink) were less likely to clear hand contamination with C. difficile. Interestingly, C. difficile was recovered from the hands of 3 (6%) of patients who didn’t have C. difficile contamination before hand hygiene!
The level of hand hygiene identified on patients with symptomatic C. difficile was lower than in a previous study (15% in this study vs. 32% in the previous study). However, the study illustrates the persistence of C. difficile on the hands of patients, and highlights the challenges of delivering effective hand hygiene to patients with limited mobility. A recent study found that wipes designed for patient hand hygiene were as effective as soap and water for removing microbes in a laboratory setting. These wipes would be a useful way to improve patient hand hygiene, especially for patients with limited mobility.
We all enjoyed Infection Prevention 2017 — and hope that you did too! Here's a few scientific updates relating to our product range that were presented at the conference, published in the Journal of Infection Prevention:
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