Risks and benefits of using chlorhexidine gluconate in handwashing: A systematic literature review

Emergence and clonal expansion of a qacA-harbouring sequence type 45 lineage of methicillin-resistant Staphylococcus aureus

The past decade has seen an increase in the prevalence of sequence type (ST) 45 methicillin-resistant Staphylococcus aureus (MRSA), yet the underlying drivers for its emergence and spread remain unclear. To better understand the worldwide dissemination of ST45 S. aureus, we performed phylogenetic analyses of Australian isolates, supplemented with a global population of ST45 S. aureus genomes. Our analyses revealed a distinct lineage of multidrug-resistant ST45 MRSA harbouring qacA, predominantly found in Australia and Singapore. Bayesian inference predicted that the acquisition of qacA occurred in the late 1990s. qacA was integrated into a structurally variable region of the chromosome containing Tn552 (carrying blaZ) and Tn4001 (carrying aac(6')-aph(2")) transposable elements. Using mutagenesis and in vitro assays, we provide phenotypic evidence that qacA confers tolerance to chlorhexidine. These findings collectively suggest both antimicrobial resistance and the carriage of qacA may play a role in the successful establishment of ST45 MRSA.

Evaluation of Environmental Stability and Disinfectant Effectiveness for Human Coronavirus OC43 on Human Skin Surface

The environmental stability of human coronavirus OC43 (HCoV-OC43) on the surface of human skin and the effectiveness of disinfectant against HCoV-OC43, which are important to prevent contact transmission, have not been clarified in previous studies. Using previously generated models, we evaluated HCoV-OC43 stability and disinfection effectiveness. Then we compared the results with those for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The median survival time of HCoV-OC43 on the surface of human skin was 24.6 h (95% confidence interval, 19.7 to 29.6 h), which was higher than that of SARS-CoV-2 (10.8 h). Although the in vitro disinfectant effectiveness evaluation showed that HCoV-OC43 has a higher ethanol resistance than SARS-CoV-2, HCoV-OC43 on the skin surface was completely inactivated by a minimum of 50% ethanol within 5 s (the log reduction values were >4.0). Moreover, 1.0% chlorhexidine gluconate and 0.2% benzalkonium chloride showed relatively high disinfectant effectiveness, and the log reduction values when these disinfectants were applied for 15 s were >3.0. HCoV-OC43 is highly stable on the skin surface, which may increase the risk of contact transmission. Although HCoV-OC43 has relatively high ethanol resistance, appropriate hand hygiene practices with current alcohol-based disinfectants sufficiently reduce the risk of contact transmission. IMPORTANCE This study revealed the environmental stability of HCoV-OC43 and disinfectant effectiveness against HCoV-OC43, which had not been demonstrated in previous studies. HCoV-OC43 is highly stable on the surface of human skin, with a survival time of approximately 25 h. High stability of HCoV-OC43 may increase the risk of contact transmission. Furthermore, the in vitro disinfectant effectiveness evaluation showed that HCoV-OC43, which is classified as an envelope virus, has a relatively high ethanol resistance. This finding suggests that disinfectant effectiveness may vary greatly depending on the virus and that each virus targeted for infection control should be evaluated individually. HCoV-OC43 on the skin surface was rapidly inactivated by 50% ethanol, which suggests that appropriate hand hygiene practices with current alcohol-based disinfectants can sufficiently reduce the risk of HCoV-OC43 contact transmission.

Risks of ozonated oil and ozonated water on human skin: A systematic review

Ozonated water and oil are emerging as potential dermatologic therapeutics, particularly for the treatment of various wounds. However, the safety of these liquids has not been extensively studied. The aim of this systematic review was to evaluate the risks of ozonated liquids to human skin tissue based on the available literature. We completed a structured search of five scientific databases and identified 378 articles for consideration. Based on pre‐established inclusion/exclusion criteria, nine studies were included in this review. Two studies specifically evaluated the cytotoxicity of ozonated liquids on human cells, five studies evaluated ozonated liquids in randomised controlled trials (RCTs), one was a post‐market surveillance study, and one was a crossover study in humans. None of the included studies found any significant human dermatologic risks associated with ozonated water or liquid. Because of the small sample size, however, additional short‐ and long‐term RCTs specifically designed to evaluate the dermatological risks of ozonated liquids are recommended.

Antimicrobial Resistance Following Prolonged Use of Hand Hygiene Products: A Systematic Review

Background: This systematic review aimed to establish whether antimicrobial resistance (AMR) occurs following prolonged use of antimicrobial hand hygiene (HH) products, and, if so, in what magnitude. Methods: Key bibliographic databases were searched to locate items on HH use and AMR development from database inception to December 2020. Records were screened and full texts of all potentially eligible articles were retrieved and checked for inclusion. The following data from the included studies were abstracted: type of HH product used, including the name of antimicrobial agent, study setting, country, study year, duration of use and development of AMR including the organisms involved. Quality assessment was done using the Newcastle-Ottawa Scale (NOS). Results: Of 339 full-text articles assessed for eligibility, only four heterogeneous United States (US) studies conducted in the period between 1986 and 2015 were found eligible, and included. One hospital-based study showed evidence of AMR following long term use of HH products, two studies conducted in household settings showed no evidence of AMR, and another experimental study showed partial evidence of AMR. The overall certainty of the evidence was moderate. Conclusion: Prolonged use of HH products may cause AMR in health care settings, but perhaps not in other settings.

Evaluation of the Residual Disinfection Effects of Commonly Used Skin Disinfectants against Viruses: An Innovative Contact Transmission Control Method

Lasting disinfection effects, that is, the residual disinfection effects (RDEs), of skin-coated disinfectants have rarely been considered for infection control owing to the challenges involved in the accurate evaluation of RDEs. In this study, we constructed a new skin evaluation model and determined the RDEs of existing disinfectants against viruses. Our results showed that ethanol and isopropanol had no RDE, whereas povidone-iodine, chlorhexidine gluconate, and benzalkonium chloride (BAC) exhibited RDEs, with 10% povidone-iodine and 0.2% BAC showing particularly strong RDEs. The RDE of 0.2% BAC was strong enough to reduce the median survival times of severe acute respiratory syndrome coronavirus-2, human coronavirus-OC43, and influenza virus from 670 to 5.2, 1300 to 12, and 120 to 4.2 min, respectively. Additionally, this strong RDE was maintained even 4 h after coating the skin. Clinical data also showed that the strong RDE of 0.2% BAC was maintained for more than 2 h. Thus, applying disinfectants with strong RDEs on the skin correlates with a reduction in virus survival time and appears to create a skin surface environment that is not conducive to virus survival. A prolonged reduction in virus survival decreases the contact transmission risk, thereby enabling stronger infection control.

Antiseptic efficacy of an innovative perioperative surgical skin preparation: A confirmatory FDA phase 3 analysis

BACKGROUND

An innovative approach to perioperative antiseptic skin preparation is warranted because of potential adverse skin irritation, rare risk of serious allergic reaction, and perceived diminished clinical efficacy of current perioperative antiseptic agents. The results of a confirmatory US Food and Drug Administration (FDA) phase 3 efficacy analysis of a recently approved innovative perioperative surgical skin antiseptic agent are discussed.

METHODS

The microbial skin flora on abdominal and groin sites in healthy volunteers were microbiologically sampled following randomization to either ZuraGard, a 2% chlorhexidine/70% isopropyl alcohol preparation (Chloraprep), or a control vehicle (alcohol-free ZuraGard). Mean log10 reduction of colony-forming units (CFU) was assessed at 30 seconds, 10 minutes, and 6 hours.

RESULTS

For combined groin sites (1,721 paired observations) at all time points, the mean log10 CFU reductions were significantly greater in the ZuraGard group than in the Chloraprep group (P < .02). Mean log10 CFU reductions across combined abdominal and groin sites at all time points (3,277 paired observations) were significantly greater in the ZuraGard group than in the Chloraprep group (P < .02).

CONCLUSIONS

A confirmatory FDA phase 3 efficacy analysis of skin antisepsis in human volunteers documented that ZuraGard was efficacious in significantly reducing the microbial burden on abdominal and groin test sites, exceeding that of Chloraprep. No significant adverse reactions were observed following the application of ZuraGard.

TRIAL REGISTRATION

ClinicalTrials.gov identifiers: NCT02831998 and NCT02831816.