Induced sporicidal activity of chlorhexidine against Clostridium difficile spores under altered physical and chemical conditions

Enhancement of microbicidal efficacy of chemical disinfectants when combined with ultrasound technology

AIMS

This study investigated the antimicrobial efficacy of ultrasound technology (US) in combination with two different disinfectants (Disinfectant A and Disinfectant B), containing peracetic acid (PAA) and quaternary ammonium compounds (QACs), respectively, against two sporigenic pathogens, Aspergillus brasiliensis and Bacillus subtilis.

METHODS AND RESULTS

The microbicidal activity of the coupled treatment was compared with the use of the disinfectants alone, and the efficacy of the disinfection strategies was evaluated by the log reduction of the population of the microorganism inoculated onto stainless-steel surface. The combination treatment resulted in a log reduction of 5.40 and 3.88 (Disinfectant A + US) against A. brasiliensis and B. subtilis, at 850 and 500 ppm PAA, compared to 265 and 122 (Disinfectant A only). For Disinfectant B, in combination with US, showed a logarithmic reduction of 5.04 and 4.79 against A. brasiliensis and B. subtilis at 078% v v-1 and 392% v v-1 QACs, respectively, vs. 1.58 and 1.64 (Disinfectant B only). Moreover, no colonies or not statistically significant growth was observed within the US bath containing the disinfectant.

CONCLUSIONS

The antimicrobial efficacy of the two disinfectants was greatly enhanced when used in combination with US, and this also makes it possible to avoid the overuse of chemicals for disinfection.

Biocides in the Hospital Environment: Application and Tolerance Development

Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.

[Effect of 2% Chlorhexidine Bathing on the Incidence of Hospital-Acquired Infection and Multidrug-Resistant Organisms in Adult Intensive Care Unit Patients: Systematic Review and Meta-Analysis]

PURPOSE

This systematic review and meta-analysis analyzed the effects of 2% chlorhexidine bathing on the incidence of hospital-acquired infection (HAI) and multidrug-resistant organisms (MDRO) in adult intensive care units.

METHODS

PubMed, CINAHL, Cochrane library, and RISS database were systematically searched, and 12 randomized studies were included in the analysis. Comprehensive Meta-Analysis version 3.0 was used to calculate the effect size using the odds ratio (OR) and a 95% confidence interval (CI). Subgroup analysis was performed according to the specific infection and intervention types.

RESULTS

In general, 2% chlorhexidine bathing has a significant effect on the incidence of HAI (OR, 0.59; 95% CI, 0.40~0.86) and MDRO (OR, 0.52; 95% CI, 0.34~0.79). Subgroup analyses show 2% chlorhexidine bathing is effective in bloodstream infections (OR, 0.51; 95% CI, 0.39~0.66) but not for urinary tract infections, ventilator-associated pneumonia infections, and Clostridium difficile infections. Moreover, 2% chlorhexidine bathing alone or its combination with other interventions has a significant effect on the incidence of HAI and MDRO (OR, 0.59; 95% CI, 0.38~0.92).

CONCLUSION

This meta-analysis reveals that 2% chlorhexidine bathing significantly reduces the incidence of HAI and MDRO in intensive care units. The effect of 2% chlorhexidine bathing on pediatric patients or patients at general wards should be further assessed as a cost-effective intervention for infection control.

What's new and notable in bacterial spore killing!

Spores of many species of the orders Bacillales and Clostridiales can be vectors for food spoilage, human diseases and intoxications, and biological warfare. Many agents are used for spore killing, including moist heat in an autoclave, dry heat at elevated temperatures, UV radiation at 254 and more recently 222 and 400 nm, ionizing radiation of various types, high hydrostatic pressures and a host of chemical decontaminants. An alternative strategy is to trigger spore germination, as germinated spores are much easier to kill than the highly resistant dormant spores—the so called “germinate to eradicate” strategy. Factors important to consider in choosing methods for spore killing include the: (1) cost; (2) killing efficacy and kinetics; (3) ability to decontaminate large areas in buildings or outside; and (4) compatibility of killing regimens with the: (i) presence of people; (ii) food quality; (iii) presence of significant amounts of organic matter; and (iv) minimal damage to equipment in the decontamination zone. This review will summarize research on spore killing and point out some common flaws which can make results from spore killing research questionable.

Chlorhexidine Gluconate Bathing Reduces the Incidence of Bloodstream Infections in Adults Undergoing Inpatient Hematopoietic Cell Transplantation

Bloodstream infections (BSIs) occur in 20% to 45% of inpatient autologous and allogeneic hematopoietic cell transplant (HCT) patients. Daily bathing with the antiseptic chlorhexidine gluconate (CHG) has been shown to reduce the incidence of BSIs in critically ill patients, although very few studies include HCT patients or have evaluated the impact of compliance on effectiveness. We conducted a prospective cohort study with historical controls to assess the impact of CHG bathing on the rate of BSIs and gut microbiota composition among adults undergoing inpatient HCT at the Duke University Medical Center. We present 1 year of data without CHG bathing (2016) and 2 years of data when CHG was used on the HCT unit (2017 and 2018). Because not all patients adhered to CHG, patients were grouped into four categories by rate of daily CHG usage: high (>75%), medium (50% to 75%), low (1% to 49%), and none (0%). Among 192 patients, univariate trend analysis demonstrated that increased CHG usage was associated with decreased incidence of clinically significant BSI, defined as any BSI requiring treatment by the medical team (high, 8% BSI; medium, 15.2%; low, 15.6%; no CHG, 30.3%; P = .003), laboratory-confirmed BSI (LCBI; P = .03), central line-associated BSI (P = .04), and mucosal barrier injury LCBI (MBI-LCBI; P = .002). Multivariate analysis confirmed a significant effect of CHG bathing on clinically significant BSI (P = .023) and MBI-LCBI (P = .007), without consistently impacting gut microbial diversity. Benefits of CHG bathing were most pronounced with >75% daily usage, and there were no adverse effects attributable to CHG. Adherence to daily CHG bathing significantly decreases the rate of bloodstream infection following HCT.

Association Between Eliminating Water From Surgical Hand Antisepsis at a Large Ophthalmic Surgical Hospital and Cost

Importance

Alcohol-based surgical scrub is recommended for presurgical antisepsis by leading health organizations. Despite this recommendation, water-based scrub techniques remain common practice at many institutions.

Objective

To calculate the potential financial savings that a large, subspecialty ophthalmic surgical center can achieve with a conversion to waterless surgical hand preparation.

Design, Setting, and Participants

A review of accounting records associated with the purchase of scrubbing materials and water company invoices was conducted to assess direct costs attributable to water consumption and scrub materials for brushless, alcohol-based surgical scrub and water-based presurgical scrub. The flow rate of scrub sinks to estimate water consumption per year was tested. Savings associated with operating room (OR) and personnel time were calculated based on the prescribed scrub times for waterless techniques vs traditional running-water techniques. The study was conducted from January 5 to March 1, 2019.

Main Outcomes and Measures

The primary outcomes for this study were the quantity of water consumed by aqueous scrubbing procedures as well as the cost differences between alcohol-based surgical scrub and water-based scrub procedures per OR per year.

Results

Scrub sinks consumed 15.9 L of water in a 2-minute period, projecting a savings of 61 631 L and $277 in water and sewer cost per operating room per year. Alcohol-based surgical scrub cost $1083 less than aqueous soap applied from wall-mounted soap dispensers and $271 less than preimpregnated scrub brushes per OR per year in supply costs. The decrease in scrub time from adopting waterless scrub technique could save between approximately $280 000 and $348 000 per OR per year.

Conclusions and Relevance

Adopting waterless scrub techniques has the potential for economic savings attributable to water. Savings may be larger for surgical facilities performing more personnel-intensive procedures.

CLOSTRIDIUM PERFRINGENS PANOPHTHALMITIS AFTER INTRAVITREAL ANTI-VASCULAR ENDOTHELIAL GROWTH FACTOR INJECTION

PURPOSE

This report describes a fulminant infection with Clostridium perfringens after an intravitreal anti-vascular endothelial growth factor injection.

METHODS

This is a retrospective case review.

RESULTS

Our patient's rapid infection eventually led to enucleation, despite broad-spectrum antibiotic therapy.

CONCLUSION

Reporting rare causes and common clinical findings of C. perfringens ocular infection may lead to earlier detection and intervention.

Prospective, randomised, controlled study evaluating early modification of oral microbiota following admission to the intensive care unit and oral hygiene with chlorhexidine

OBJECTIVES

Chlorhexidine (CHX) is the most commonly used oral hygiene product for the prevention of ventilator-associated pneumonia (VAP) in patients undergoing mechanical ventilation (MV). The change in dental plaque (DP) microbiota following CHX use in patients under MV has not been described previously. The aim of this study was to evaluate the incidence of pathogenic bacteria associated with VAP and the coverage of DP within the oral cavity in patients administered CHX.

METHODS

This was a prospective, randomised, controlled, double-blind study in patients (n=16) under MV who were mouth-rinsed with either CHX or placebo. Microbiology samples were collected from the oral mucosa (OM) and DP after admission to the ICU and on Days 3, 5, 7 and 10. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of CHX were determined.

RESULTS

Upon admission, the occurrence of multidrug-resistant (MDR) bacteria, including carbapenem-resistant Klebsiella pneumoniae, was reported. The CHX group had a lower incidence of methicillin-resistant Staphylococcus aureus (MRSA) compared with the placebo group for the OM (RR=0.51, 95% CI 0.27-0.98; P=0.011). There was high agreement between the culture results of OM and DP (κ=0.825). VAP developed in six patients. The species identified following tracheal aspiration of VAP patients were similar to those found in the OM for four cases. The strains showed low MICs and MBCs for CHX (<0.039mg/mL).

CONCLUSIONS

Although DP is rapidly colonised by MDR bacteria, use of 2% CHX reduced the incidence of S. aureus colonisation.

Effect of chlorhexidine bathing in preventing infections and reducing skin burden and environmental contamination: A review of the literature

Chlorhexidine bathing is effective in reducing levels of pathogens on skin. In this review, we examine the evidence that chlorhexidine bathing can prevent colonization and infection with health care-associated pathogens and reduce dissemination to the environment and the hands of personnel. The importance of education and monitoring of compliance with bathing procedures is emphasized in order to optimize chlorhexidine bathing in clinical practice.

A Cumulative Spore Killing Approach: Synergistic Sporicidal Activity of Dilute Peracetic Acid and Ethanol at Low pH Against Clostridium difficile and Bacillus subtilis Spores

The synergistic combination of dilute peracetic acid and ethanol at low pH provides a novel approach for development of a rapid and effective method for reducing C. difficile spores on skin.

Background. Alcohol-based hand sanitizers are the primary method of hand hygiene in healthcare settings, but they lack activity against bacterial spores produced by pathogens such as Clostridium difficile and Bacillus anthracis. We previously demonstrated that acidification of ethanol induced rapid sporicidal activity, resulting in ethanol formulations with pH 1.5–2 that were as effective as soap and water washing in reducing levels of C difficile spores on hands. We hypothesized that the addition of dilute peracetic acid (PAA) to acidified ethanol would enhance sporicidal activity while allowing elevation of the pH to a level likely to be well tolerated on skin (ie, >3).

Methods. We tested the efficacy of acidified ethanol solutions alone or in combination with PAA against C difficile and Bacillus subtilis spores in vitro and against nontoxigenic C difficile spores on hands of volunteers.

Results. Acidification of ethanol induced rapid sporicidal activity against C difficile and to a lesser extent B subtilis. The addition of dilute PAA to acidified ethanol resulted in synergistic enhancement of sporicidal activity in a dose-dependent fashion in vitro. On hands, the addition of 1200–2000 ppm PAA enhanced the effectiveness of acidified ethanol formulations, resulting in formulations with pH >3 that were as effective as soap and water washing.

Conclusions. Acidification and the addition of dilute PAA induced rapid sporicidal activity in ethanol. Our findings suggest that it may be feasible to develop effective sporicidal ethanol formulations that are safe and tolerable on skin.

TS, Setlow P, Donskey CJ. Unlocking the Sporicidal Potential of Ethanol: Induced Sporicidal Activity of Ethanol against Clostridium difficile and Bacillus Spores under Altered Physical and Chemical Conditions

Background

Due to their efficacy and convenience, alcohol-based hand sanitizers have been widely adopted as the primary method of hand hygiene in healthcare settings. However, alcohols lack activity against bacterial spores produced by pathogens such as Clostridium difficile and Bacillus anthracis. We hypothesized that sporicidal activity could be induced in alcohols through alteration of physical or chemical conditions that have been shown to degrade or allow penetration of spore coats.

Principal Findings

Acidification, alkalinization, and heating of ethanol induced rapid sporicidal activity against C. difficile, and to a lesser extent Bacillus thuringiensis and Bacillus subtilis. The sporicidal activity of acidified ethanol was enhanced by increasing ionic strength and mild elevations in temperature. On skin, sporicidal ethanol formulations were as effective as soap and water hand washing in reducing levels of C. difficile spores.

Conclusions

These findings demonstrate that novel ethanol-based sporicidal hand hygiene formulations can be developed through alteration of physical and chemical conditions.