Myelin toxicity of chlorhexidine in zebrafish larvae

BACKGROUND

Chlorhexidine gluconate (CHG) is a topical antiseptic solution recommended for skin preparation before central venous catheter placement and maintenance in adults and children. Although CHG is not recommended for use in children aged <2 months owing to limited safety data, it is commonly used in neonatal intensive care units worldwide. We used zebrafish model to verify the effects of early-life exposure to CHG on the developing nervous system, highlighting its impact on oligodendrocyte development and myelination.

METHODS

Zebrafish embryos were exposed to different concentrations of CHG from 4 h post fertilization to examine developmental toxicity. The hatching rate, mortality, and malformation of the embryos/larvae were monitored. Oligodendrocyte lineage in transgenic zebrafish embryos was used to investigate defects in oligodendrocytes and myelin. Myelin structure, locomotor behavior, and expression levels of genes involved in myelination were investigated.

RESULTS

Exposure to CHG significantly induced oligodendrocyte defects in the central nervous system, delayed myelination, and locomotor alterations. Ultra-microstructural changes with splitting and fluid-accumulated vacuoles between the myelin sheaths were found. Embryonic exposure to CHG decreased myelination, in association with downregulated mbpa, plp1b, and scrt2 gene expression.

CONCLUSION

Our results suggest that CHG has a potential for myelin toxicity in the developing brain.

IMPACT

To date, the neurodevelopmental toxicity of chlorhexidine gluconate (CHG) exposure on the developing brains of infants remains unknown. We demonstrated that CHG exposure to zebrafish larvae resulted in significant defects in oligodendrocytes and myelin sheaths. These CHG-exposed zebrafish larvae exhibited structural changes and locomotor alterations. Given the increased CHG use in neonates, this study is the first to identify the risk of early-life CHG exposure on the developing nervous system.

Synthesis, Drug Release, and Antibacterial Properties of Novel Dendritic CHX-SrCl2 and CHX-ZnCl2 Particles

This work demonstrated for the first time the synthesis of novel chlorhexidine particles containing strontium and zinc, to provide an effective, affordable, and safe intervention in the treatment of recurrent infections found in Medicine and Dentistry. The CHX-SrCl₂ and CHX-ZnCl₂ particles were synthesized by co-precipitation of chlorhexidine diacetate (CHXD) and zinc chloride or strontium chloride, where particle size was manipulated by controlling processing time and temperature. The CHX-ZnCl₂ and CHX-SrCl₂ particles were characterized using SEM, FTIR, and XRD. UV-Vis using artificial saliva (pH 4 and pH 7) was used to measure the drug release and ICP-OES ion release. The antibacterial properties were examined against P. gingivalis, A. actinomycetemcomitans, and F. nucleatum subsp. Polymorphum, and cytotoxicity was evaluated using mouse fibroblast L929 cells. The novel particles were as safe as commercial CHXD, with antibacterial activity against a range of oral pathogens. UV-Vis results run in artificial saliva (pH 4 and pH 7) indicated a higher release rate in acidic rather than neutral conditions. The CHX-ZnCl₂ particles provided the functionality of a smart Zinc and CHX release, with respect to environmental pH, allowing responsive antibacterial applications in the field of medicine and dentistry.

Analysis of chlorhexidine gluconate in skin using tape stripping and ultrahigh-performance liquid chromatography-tandem mass spectrometry

BACKGROUND

Topical chlorhexidine gluconate (CHG) is used widely to reduce healthcare-associated infection. The optimal therapeutic dose for maximum efficacy and reduced toxicity is unclear, in part because of the lack of analytical methods to monitor CHG levels in skin. A novel method was developed to accurately measure CHG levels in skin after topical application with the goal of determining its pharmacokinetics in skin.

METHODS

Ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to develop a validated assay for measuring CHG levels in skin cells collected by a non-invasive adhesive tape-stripping method. CHG levels in the skin stratum corneum of healthy adult volunteers were measured at 0.5, 4, 8, and 24 h after its application.

RESULTS

Conditions for extraction of CHG were optimized and the assay was linear in the range 0.1-50 μg/mL (corresponding to 0.2-100 μg chlorhexidine/tape), with an intra-assay precision of 1.74-10.50 % and a relative error of ≤10 %. The inter-assay accuracy was in the range of 5.86-10.96 % with a relative error <9 %. CHG was stable on tapes stored at 4 °C and ambient temperature for 14 and 3 days, respectively. The recovery of CHG from the tape was quantitative and the matrix effect was determined as 2.1-14.8 %. CHG levels in healthy adult volunteer skin following topical application decreased rapidly over a 24 h period.

CONCLUSIONS

A rapid, accurate and specific UHPLC-MS/MS method was developed for the measurement of CHG in the skin obtained by tape stripping that was linear over a large dynamic range. This assay afforded a simple and convenient non-invasive approach to monitor CHG levels in skin after topical application that can be applied to enable the optimal dose to prevent infection and minimize toxicity.

In vivo biocompatibility and in vitro efficacy of antimicrobial gendine-coated central catheters

Antimicrobial peripherally inserted central catheters (PICCs) might reduce the incidence of central line-associated bloodstream infections (CLABSI). We tested the biocompatibility of a novel gendine-coated (combination of chlorhexidine [CHX] and gentian violet [GV]) PICC in a rabbit intravascular model and tested antimicrobial efficacy in comparison with commercially available minocycline/rifampin (M/R)- and CHX-treated PICCs in an in vitro biofilm colonization model. Gendine-coated and uncoated control PICCs were inserted in the jugular veins of rabbits for 4 days. Histopathological analysis was performed at the end of the 4-day period, and circulating levels of CHX and GV in the blood were measured at different time points using liquid chromatography-mass spectrometry. The antimicrobial efficacy of the PICCs was tested following simulated intravascular indwells of 24 h and 1 week against clinical isolates of methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Pseudomonas aeruginosa, Escherichia coli, Acinetobacter baumannii, Enterobacter cloacae, Candida albicans, and Candida glabrata. Rabbits implanted with gendine-coated PICCs exhibited reduced levels of thrombosis and inflammation compared to those of the rabbits with uncoated controls. No GV was detected in blood samples over the entire study period, and trace concentrations of CHX were detected. The gendine-coated PICCs completely prevented the adherence of all pathogens from 24 h to 1 week (P ≤ 0.001), while M/R-treated, CHX-treated, and control PICCs did not. Gendine-coated PICCs were highly effective in preventing biofilm formation of multidrug-resistant pathogenic bacteria and fungi. Gendine-coated PICCs were biocompatible in an intravascular setting. Further, the pharmacokinetic testing established that acute systemic exposures of CHX and GV from the gendine-coated catheters were well within safe levels.

Chlorhexidine-associated transient hyperchloremia in an infant

An infant was cleansed with 2% clorhexidine gluconate (CHG) because of repeated sepsis episodes from skin colonization. Asymptomatic hyperchloremia ensued, most likely associated with CHG therapy. Fourty-eight hours after CHG therapy withdrawal, serum chloride levels returned to normal. Hyperchloremia may be a reversible adverse effect of extensive use of CHG.

Chlorhexidine bathing in a tertiary care neonatal intensive care unit: impact on central line-associated bloodstream infections

BACKGROUND

Despite implementation of recommended best practices, our central line-associated bloodstream infection (CLABSI) rates remained high. Our objective was to describe the impact of chlorhexidine gluconate (CHG) bathing on CLABSI rates in neonates.

METHODS

Infants with a central venous catheter (CVC) admitted to the neonatal intensive care unit from April 2009 to March 2013 were included. Neonates with a birth weight of 1,000 g or less, aged less than 28 days, and those with a birth weight greater than 1,000 g were bathed with mild soap until March 31, 2012 (baseline), and with a 2% CHG-impregnated cloth starting on April 1, 2012 (intervention). Infants with a birth weight of 1,000 g or less, aged 28 days or more, were bathed with mild soap during the entire period. Neonatal intensive care unit nurses reported adverse events. Adjusted incidence rate ratios (aIRRs), using Poisson regression, were calculated to compare CLABSIs/1,000 CVC-days during the baseline and intervention periods.

RESULTS

Overall, 790 neonates with CVCs were included in the study. CLABSI rates decreased during the intervention period for CHG-bathed neonates (6.00 vs 1.92/1,000 CVC-days; aIRR, 0.33 [95% confidence interval (CI), 0.15-0.73]) but remained unchanged for neonates with a birth rate of 1,000 g or less and aged less than 28 days who were not eligible for CHG bathing (8.57 vs 8.62/1,000 CVC-days; aIRR, 0.86 [95% CI, 0.17-4.44]). Overall, 195 infants with a birth weight greater than 1,000 g and 24 infants with a birth weight of 1,000 g or less, aged 28 days or more, were bathed with CHG. There was no reported adverse event.

CONCLUSIONS

We observed a decrease in CLABSI rates in CHG-bathed neonates in the absence of observed adverse events. CHG bathing should be considered if CLABSI rates remain high, despite the implementation of other recommended measures.

The value of chlorhexidine gluconate wipes and prepacked washcloths to prevent the spread of pathogens--a systematic review

BACKGROUND

Use of chlorhexidine gluconate wipes and pre-packed washcloths has been described for preventing pathogen spread in healthcare settings.

AIM

To assess the impact of chlorhexidine washcloths/wipes in preventing the spread of pathogens.

METHODS

Extensive and structured literature search from studies in Google Academic, Cochrane Library, Web of Science, Pubmed and Cinahl from their inception until November 2012.

FINDINGS

Final analysis included 15 studies, 9 of which were randomised controlled trials. The most frequent setting was the intensive care unit. In intensive care units, a significant reduction of bloodstream infection was associated with intervention and 3 studies revealed a decrease in blood culture contamination. One study showed a decrease in staff and environmental contamination and no increase in chlorhexidine resistance with intervention. Positive blood cultures for multiple pathogens also declined with intervention. In a paediatric intensive care unit, intervention decreased bacteraemia and catheter-associated bloodstream infection. In hospital wards, intervention was associated to a 64% reduction of pathogen transmission. One study had no statistically significant results. Pre-surgical chlorhexidine use significantly decreased bacterial colonisation but had no impact on surgical site infections. Regarding maternal and perinatal setting, one study did not show reduction of early onset neonatal sepsis and pathogen transmission. Another study of vaginal and neonatal decolonisation with chlorhexidine wiping revealed significant reduction in colonisation. One study concluded that single and multiple umbilical cord cleansing reduced the likelihood for a positive swab in 25% and 29%, respectively. Neonatal wiping maintained low levels of skin colonisation for a 24h period, for multiple pathogens.

CONCLUSION

Current evidence supports the usefulness of chlorhexidine washcloths and wipes in an intensive care, hospital and pre-surgical setting. More studies are required to encourage its use for prevention of perinatal and neonatal transmission of pathogens.

Reducing the risk of surgical site infections: does chlorhexidine gluconate provide a risk reduction benefit?

Chlorhexidine gluconate (CHG) has been available as a topical antiseptic for over 50 years, having broad clinical application throughout the health care environment. Evidence-based clinical studies have shown chlorhexidine gluconate to be a safe and effective perioperative skin-prepping agent. Renewed interest has emerged for use of the antiseptic bath/shower to reduce the microbial skin burden prior to hospital admission. Recent clinical studies have documented that multiple applications of 2% or 4% CHG using a standardized protocol results in high skin surface concentrations sufficient to inhibit/kill skin colonizing flora, including methicillin-resistant Staphylococcus aureus. A new focus for the use of CHG in surgical patients involves irrigation of the wound prior to closure with 0.05% CHG followed by saline rinse. Recent laboratory studies suggest that, following a 1-minute exposure, 0.05% CHG produces a >5-log reduction against selective health care-associated pathogens and reduces microbial adherence to the surface of implantable biomedical devices. General, orthopedic, cardiothoracic, and obstetrical surgical studies have documented the safety of selective CHG formulations in elective surgical procedures. The following discussion will address both the evidence-based literature and preliminary findings suggesting that CHG has a broad and safe range of applications when used as an adjunctive interventional strategy for reducing the risk of postoperative surgical site infections (SSI).

Daily chlorhexidine bathing to reduce bacteraemia in critically ill children: a multicentre, cluster-randomised, crossover trial

BACKGROUND

Bacteraemia is an important cause of morbidity and mortality in critically ill children. Our objective was to assess whether daily bathing in chlorhexidine gluconate (CHG) compared with standard bathing practices would reduce bacteraemia in critically ill children.

METHODS

In an unmasked, cluster-randomised, two-period crossover trial, ten paediatric intensive-care units at five hospitals in the USA were randomly assigned a daily bathing routine for admitted patients older than 2 months, either standard bathing practices or using a cloth impregnated with 2% CHG, for a 6-month period. Units switched to the alternative bathing method for a second 6-month period. 6482 admissions were screened for eligibility. The primary outcome was an episode of bacteraemia. We did intention-to-treat (ITT) and per-protocol (PP) analyses. This study is registered with ClinicalTrials.gov (identifier NCT00549393).

FINDINGS

1521 admitted patients were excluded because their length of stay was less than 2 days, and 14 refused to participate. 4947 admissions were eligible for analysis. In the ITT population, a non-significant reduction in incidence of bacteraemia was noted with CHG bathing (3·52 per 1000 days, 95% CI 2·64-4·61) compared with standard practices (4·93 per 1000 days, 3·91-6·15; adjusted incidence rate ratio [aIRR] 0·71, 95% CI 0·42-1·20). In the PP population, incidence of bacteraemia was lower in patients receiving CHG bathing (3·28 per 1000 days, 2·27-4·58) compared with standard practices (4·93 per 1000 days, 3·91-6·15; aIRR 0·64, 0·42-0·98). No serious study-related adverse events were recorded, and the incidence of CHG-associated skin reactions was 1·2 per 1000 days (95% CI 0·60-2·02).

INTERPRETATION

Critically ill children receiving daily CHG bathing had a lower incidence of bacteraemia compared with those receiving a standard bathing routine. Furthermore, the treatment was well tolerated.

FUNDING

Sage Products, US National Institutes of Health.

Empirical power and sample size calculations for cluster-randomized and cluster-randomized crossover studies

In recent years, the number of studies using a cluster-randomized design has grown dramatically. In addition, the cluster-randomized crossover design has been touted as a methodological advance that can increase efficiency of cluster-randomized studies in certain situations. While the cluster-randomized crossover trial has become a popular tool, standards of design, analysis, reporting and implementation have not been established for this emergent design. We address one particular aspect of cluster-randomized and cluster-randomized crossover trial design: estimating statistical power. We present a general framework for estimating power via simulation in cluster-randomized studies with or without one or more crossover periods. We have implemented this framework in the clusterPower software package for R, freely available online from the Comprehensive R Archive Network. Our simulation framework is easy to implement and users may customize the methods used for data analysis. We give four examples of using the software in practice. The clusterPower package could play an important role in the design of future cluster-randomized and cluster-randomized crossover studies. This work is the first to establish a universal method for calculating power for both cluster-randomized and cluster-randomized clinical trials. More research is needed to develop standardized and recommended methodology for cluster-randomized crossover studies.

Safety of chlorhexidine gluconate used for skin antisepsis in the preterm infant

Chlorhexidine gluconate (CHG) is a widely used topical antiseptic that is recommended by the Centers for Disease Control and Prevention for skin cleansing before central venous catheter insertion in adults and children. Because of limited safety data, CHG is not recommended for use in children <2 months of age. CHG is, however, frequently used in Neonatal Intensive Care Units across the United States. Here, we will review the safety of CHG use in preterm infants.