Antimicrobial persistence of two alcoholic preoperative skin preparation solutions.

BACKGROUND: Normal skin flora and suboptimal skin antisepsis are the primary drivers of healthcare-associated infections (HAIs). Antimicrobial persistence of preoperative skin preparation is necessary to limit microorganisms on the skin and help minimize their entry into an incision or device-insertion site after application. AIM: To assess the antimicrobial persistence of two preoperative skin preparation solutions. METHODS: A randomized, single-centre, partially blinded, clinical study was conducted in 103 healthy volunteers to evaluate the persistent antimicrobial properties of BD ChloraPrep™ (2% w/v chlorhexidine gluconate [CHG] + 70% v/v isopropyl alcohol [IPA]) and BD PurPrep™ (8.3% w/w povidone-iodine [PVPI] + 72.5% w/w IPA) skin preparations out to 7 days and 96 h, respectively, on abdomen and groin testing sites. An additional 32 healthy volunteers participated in a neutralization procedure to ensure that the study recovery solution was non-toxic to microorganisms, and a spore-recovery procedure to demonstrate that microorganisms could be successfully recovered from the PVP-I+IPA film-forming product. FINDINGS: Both CHG+IPA and PVP-I+IPA produced a mean bacterial log10 reduction >2 and >3 on the abdomen and groin, respectively, 10 min after application. CHG+IPA maintained antimicrobial persistence out to 7 days post application, whereas PVP-I+IPA maintained antimicrobial persistence out to 96 h post application, the longest time-point selected for this product. CONCLUSION: CHG+IPA and PVP-I+IPA were both found to be effective, persistent antiseptic skin preparations. Overall, skin irritation was uncommon, and only one adverse event occurred following product application, which was not considered product-related but was considered procedure-related.

Is there an optimal sampling time and number of samples for assessing exposure to fast elimination endocrine disruptors with urinary biomarkers?

In studies investigating the effects of endocrine disruptors (ED) such as phthalates, bisphenols and some pesticides on human health, exposure is usually characterized with urinary metabolites. The variability of biomarkers concentration, due to rapid elimination from the body combined with frequent exposure is however pointed out as a major limitation to exposure assessment. This study was conducted to assess variability of urinary metabolites of ED, and to investigate how sampling time and number of samples analyzed impacts exposure assessment. Urine samples were collected over 6 months from 16 volunteers according to a random sampling design, and analyzed for 16 phthalate metabolites, 9 pesticide metabolites and 4 bisphenols. The amount of biomarkers excreted in urine at different times of the day were compared. In parallel, 2 algorithms were developed to investigate the effect of the number of urine samples analyzed per subject on exposure assessment reliability. In the 805 urine samples collected from the participants, all the biomarkers tested were detected, and 18 were present in >90% of the samples. Biomarkers variability was highlighted by the low intraclass correlation coefficients (ICC) ranging from 0.09 to 0.51. Comparing the amount of biomarkers excreted in urine at different time did not allow to identify a preferred moment for urine collection between first day urine, morning, afternoon and evening. Algorithms demonstrated that between 10 (for monobenzyl (MBzP) phthalate) and 31 (for bisphenol S) samples were necessary to correctly classify 87.5% of the subjects into quartiles according to their level of exposure. The results illustrate the high variability of urinary biomarkers of ED over time and the impossibility to reliably classify subjects based on a single urine sample (or a limited number). Results showed that classifying individuals based on urinary biomarkers requires several samples per subject, and this number is highly different for different biomarkers.

Evaluating the evidence for non-monotonic dose-response relationships: A systematic literature review and (re-)analysis of in vivo toxicity data in the area of food safety.

This study aims to evaluate the evidence for the existence of non-monotonic dose-responses (NMDRs) of substances in the area of food safety. This review was performed following the systematic review methodology with the aim to identify in vivo studies published between January 2002 and February 2015 containing evidence for potential NMDRs. Inclusion and reliability criteria were defined and used to select relevant and reliable studies. A set of six checkpoints was developed to establish the likelihood that the data retrieved contained evidence for NMDR. In this review, 49 in vivo studies were identified as relevant and reliable, of which 42 were used for dose-response analysis. These studies contained 179 in vivo dose-response datasets with at least five dose groups (and a control group) as fewer doses cannot provide evidence for NMDR. These datasets were extracted and analyzed using the PROAST software package. The resulting dose-response relationships were evaluated for possible evidence of NMDRs by applying the six checkpoints. In total, 10 out of the 179 in vivo datasets fulfilled all six checkpoints. While these datasets could be considered as providing evidence for NMDR, replicated studies would still be needed to check if the results can be reproduced to rule out that the non-monotonicity was caused by incidental anomalies in that specific study. This approach, combining a systematic review with a set of checkpoints, is new and appears useful for future evaluations of the dose response datasets regarding evidence of non-monotonicity.

In vivo evaluation of the persistant and residual antimicrobial properties of three hand-scrub and hand-rub regimes in a simulated surgical environment.

BACKGROUND: The use of antimicrobial formulations for disinfecting hands prior to surgery has been shown to reduce the incidence of surgical site infections. Such formulations must demonstrate an immediate reduction of microbial flora on the hands that persists while the hands are gloved. AIM: This study compared persistent and residual antimicrobial effects of three simulated in-use surgical hand-cleansing procedures, one using a scrub followed by a hand rub with products containing chlorhexidine gluconate (CHG), and two using a scrub with a cleansing soap followed by a hand rub with one of two alcohol-based products. METHODS: The study was executed in two phases. In phase 1, persistent antimicrobial effects versus the resident microbial flora of volunteer subjects' hands were evaluated. In phase 2, the residual antimicrobial effects were challenged with the application of Staphylococcus aureus (ATCC 6538) on to the hands of volunteer subjects. FINDINGS: Phase 1 testing showed that significantly greater reductions of normal flora (P ≤ 0.00) persisted with a scrub with the CHG product followed by alcohol/CHG hand rub, than were achieved by scrubs with soap followed by application of either of the other hand rubs. Through all protocols of phase 2, the CHG scrub and alcohol/CHG hand rub produced significantly greater reductions of the S. aureus population (P ≤ 0.00) than did a soap scrub in combination with the other two hand rubs. CONCLUSION: The combination of a scrub and rub with products containing CHG and alcohol was shown to reduce significantly and persistently both the resident flora and contaminating transient bacteria on skin beneath surgical gloves.

To what extent are biomonitoring data available in chemical risk assessment?

1. Chemical risk assessment integrates the identification of hazards and the human exposure levels which can be established from external and/or internal exposure data. 2. The availability of biomonitoring and metabolism animal data, the skin penetration ability, and the existence of atmospheric threshold limit values were examined for twelve substances of the European first list of priority existing substances. This investigation was focused on workplace exposures and on urinary biomarkers of exposure. Appropriate biomonitoring data appeared to be available for two substances: styrene and trichloroethylene. Some biomonitoring research has been conducted on acrylonitrile, buta-1,3-diene, cyclohexane, 1,4-dichlorobenzene, hydrogen fluoride, 2-(2-methoxyethoxy)ethanol, however additional studies could be usefully carried out. No biomonitoring data are available for alkanes, C10-13, chloro; benzene, C10-13-alkyl derivatives; bis(pentabromophenyl)ether; diphenylether, octabromo-derivative. 3. It was concluded that in some cases, biomonitoring data are either lacking or scarce. This is rather surprising since the selection of the substances of the priority list was based on high tonnage, widespread use, extent of human exposure, and toxicological concern. The development of biomonitoring information could be helpful in assessing individual or population chemical exposure whatever the source and route, and would result in both more realistic and more accurate risk assessments.