Application of a spatially resolved model to contextualise monitoring data for risk assessment of down-the-drain chemicals over large scales.

Many regulatory screening level exposure assessments are based on simple large scale conceptual scenarios. However, exposure, and therefore risks associated with chemicals, are characterised by high spatial variability. The Scenario assembly tool (ScenAT) is a global screening level model to enable spatially resolved local predictions of environmental concentrations of home and personal care chemicals. It uses the European Union Technical Guidance Document (TGD) equation to predict local scale freshwater concentrations (predicted environmental concentrations - PECs) of chemicals discharged via wastewater. ScenAT uses Geographic Information System (GIS) layers for the underlying socio-economic (population) and environmental parameters (per capita water use, sewage treatment plant connectivity, dilution factor). Using a probabilistic approach, we incorporate sources of uncertainty in the input data (tonnage estimation, removal in sewage treatment plants and seasonal variability in dilution factors) for two case-study chemicals: the antimicrobial triclosan (TCS) and the anionic surfactant linear alkylbenzene sulphonate (LAS). We then compare model estimates of wastewater and freshwater concentrations of TCS and LAS to UK monitoring data. Comparison showed that modeled PECs were on average higher than mean measured data for TCS and LAS by a factor 1.8 and 1.4, respectively. Considering the uncertainty associated with both model and monitoring data, the use of a probabilistic approach using the ScenAT model for screening assessment is reasonable. The combination of modelled and monitoring data enables the contextualisation of monitoring data. Spatial PECs can be used to identify areas of elevated concentration for further refined assessment.

Molecular epidemiology of a Pseudomonas aeruginosa hospital outbreak driven by a contaminated disinfectant-soap dispenser.

BACKGROUND AND OBJECTIVE: Pseudomonas aeruginosa infection represents a main cause of morbidity and mortality among immunocompromised patients. This study describes a fatal epidemic of P. aeruginosa that occurred in a hematology unit in Italy. METHODS: Retrospective cohort study, prospective surveillance, auditing, extensive testing on healthcare workers and environmental investigation were performed to define the dynamics and potential causes of transmission. RAPD, macrorestriction analyses and sequence typing were used to define relationships between P. aeruginosa isolates. RESULTS: Eighteen cases of infection were identified in the different phases of the investigation. Of these, five constitute a significant molecular cluster of infection. A P. aeruginosa strain with the same genetic fingerprint and sequence type (ST175) as clinical isolates strain was also isolated from a heavily contaminated triclosan soap dispenser. DISCUSSION AND CONCLUSIONS: Our results are consistent with the hypothesis that patients became indirectly infected, e.g., during central venous catheter handling through contaminated items, and that the triclosan soap dispenser acted as a common continuous source of P. aeruginosa infection. Since P. aeruginosa is intrinsically unsusceptible to triclosan, the use of triclosan-based disinfectant formulations should be avoided in those healthcare settings hosting patients at high risk of P. aeruginosa infection.

Biomonitoring Equivalents for triclosan.

Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite(s) in a biological medium (blood, urine, or other medium) consistent with an existing health-based exposure guideline, and are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for triclosan based on recent evaluations from the United States Environmental Protection Agency (US EPA), the European Commission's Scientific Committee on Consumer Products (EC SCCP) and the Australian National Industrial Chemicals Notification and Assessment Scheme (NICNAS). BE values corresponding to the reference dose (RfD) or margin of safety (MOS) targets from these agencies were derived based on kinetic data (urinary excretion and plasma clearance) from human studies and measured blood concentration data in animal studies. Estimated BE values for urinary total triclosan (free plus conjugates) corresponding to the US EPA RfD and the EC-identified margin of safety target from the NOAEL are 6.4 and 2.6 mg/L, respectively (corresponding to 8.3 and 3.3mg/g creatinine, respectively). Plasma BE values corresponding to the US EPA, EC, and Australian NICNAS values are 0.3, 0.9, and 0.4 mg/L, respectively. These values may be used as screening tools for evaluation of population biomonitoring data for triclosan in a risk assessment context.

Eficacia del cloruro de cetilpiridinio y el triclosan como antiséptico de la cavidad bucal / Efficacy of cetylpyridinium chloride and triclosan as an antiseptic in the oral cavity

Tanto el cloruro de cetilpiridinio como el triclosan, se encuentran presentes en gran cantidad de formulaciones usadas en la higiene bucal por sus propiedades antisépticas, específicamente en los líquidos enjuagatorios o enjuagues bucales. El objetivo de este estudio fue evaluar la eficacia del cloruro de cetilpiridinio (colgate plax Overnight®) y el triclosán (colgate plax menta®) como antisépticos en la cavidad bucal. Se tomaron muestras mediante hisopado de la cavidad oral de 10 jóvenes antes y después de la utilización de ambos productos siguiendo las instrucciones de uso. Las muestras fueron leídas a la 1 hora, Se transportaron en medio de Stuart hasta la lectura microbiológica previo cultivo bacteriológico. Los recuentos microbiológicos se enfocaron a los grupos bacterianos aerobios y anaerobios. Como resultado de este estudio, se determinó que tanto el cloruro de cetilpiridinio y el triclosán presentaron diferencias estadísticamente significativas sobre los grupos bacterianos aerobios y anaerobios, presentando eficacia; así como fue significativamente distinto el recuento bacteriano antes y después del uso de los productos.

Remoção da placa bacteriana em pacientes ortodônticos / Plaque removal in orthodontic patients

O objetivo desta pesquisa foi comparar o controle da placa bacteriana em pacientes ortodônticos ao utilizarem um dentifrício contendo triclosan e outro controle. Foram selecionados, aleatoriamente, 13 pacientes e divididos em dois grupos: o primeiro grupo utilizou durante três meses o dentifrício experimental e o segundo grupo utilizou, durante o mesmo período, um dentifrício controle e vice-versa. Foram realizadas avaliações dos Índices Gengival e de Placa em diferentes períodos de tempo. Os resultados, submetidos ao teste T de Student, indicaram que não houve diferença estatisticamente significativa entre dentifrício controle e o experimental utilizados.

Handwashing: what is the best solution?

The options for keeping hands clean in hospital include soap; antimicrobial solutions; iodine and iodophours; and alcohol solutions and rubs. Following the recent directive for alcohol rubs to be placed at hospital bedsides, this paper considers the pros and cons of these and other hand-hygiene methods.

Use of antimicrobial agents in consumer products.

OBJECTIVES: To summarize available data on the effectiveness of antimicrobial ingredients in consumer products such as hand lotions and soaps and to discuss the implications of such use on antimicrobial resistance. DATA SOURCES: We searched the MEDLINE database, 1966 to 2001, using the search term resistance qualified with the terms consumer product(s), OR soap, OR lotion, OR triclosan, and LexisNexis and the World Wide Web using the search strategy antimicrobial resistance AND consumer product. DATA EXTRACTION: English-language articles were selected that provided information on the use of antimicrobial ingredients in consumer products and the effect of this use on antimicrobial resistance. DATA SYNTHESIS: Despite the recent substantial increase in the use of antimicrobial ingredients in consumer products, the effects of this practice have not been studied extensively. No data support the efficacy or necessity of antimicrobial agents in such products, and a growing number of studies suggest increasing acquired bacterial resistance to them. Studies also suggest that acquired resistance to the antimicrobial agents used in consumer products may predispose bacteria to resistance against therapeutic antibiotics, but further research is needed. Considering available data and the critical nature of the antibiotic-resistance problem, it is prudent to avoid the use of antimicrobial agents in consumer products. CONCLUSIONS: The use of common antimicrobials for which acquired bacterial resistance has been demonstrated should be discontinued in consumer products unless data emerge to conclusively show that such resistance has no effect on public health and that such products are effective at preventing infection. Ultimately, antibiotic resistance must be controlled through judicious use of antibiotics by health care professionals and the public.

Antibacterial efficacy of triclosan-incorporated polymers.

Triclosan (2, 4, 4'-trichloro-2'-hydroxydiphenyl ether) is a broad-spectrum antimicrobial agent, routinely used in various personal care products.(1) It is also incorporated into polymers through melt-mixing, with the aim of providing persistent antibacterial action on the surface of the polymer.(2,3) Such triclosan-incorporated polymers can be promoted for hospital use as fabric seat covers, tables, chairs, and clothing. We assessed the antibacterial efficacy of triclosan-incorporated polymer disks against 2 bacteria cultured in liquids in contact with the polymer. In spite of the relatively high concentrations of triclosan in the polymer, only some initial slowing of the bacterial growth rates was observed, followed by the absence of an antibacterial effect over extended periods. The triclosan at the surface of the disks dissolves into the liquids, and the rest of the triclosan, immobilized in the disks, does not contribute to the antibacterial effectiveness of triclosan-incorporated polymer. In light of recent studies, which have shown that triclosan acts on a specific target within the bacterial lipid synthesis pathway, triclosan-incorporated polymers may provide the ideal setting for resistant strains of bacteria to grow and thus should be used selectively in hospital environments.

Triclosan: applications and safety.

Triclosan (2,4,4'-trichloro-2'-hydroxydiphenyl ether) is a nonionic, broad spectrum, antimicrobial agent that, because of its favorable safety profile, has been incorporated into a variety of many personal care products, including deodorant soaps, underarm deodorants, shower gels, and health care personnel handwashes. Triclosan exhibits a moderate degree of substantivity to the skin, and, in many products, it imparts a remnant antimicrobial effect. Although direct contact with the material under exaggerated exposure conditions causes dermal irritation in laboratory animals, it has only rarely been associated with skin irritation or sensitization in human being in formulated products. Acute, subacute/subchronic, and chronic toxicity profiles have been established to determine that triclosan is neither an acute oral toxicant nor that it acts as a carcinogen, mutagen, or teratogen. A new application for triclosan is in oral dentifrices for plaque control. Currently under investigation in the United States, it is approved for oral care application in Canada and many European countries.

A microbiological in-use comparison of surgical hand-washing agents.

Seven different surgical hand-scrub agents (one triclosan compound, two hexachlorophene compounds, and four iodophors) were evaluated under in-use conditions by five persons for efficacy in degerming the hands and forearms prior to performing a total of 215 total hip arthroplasties. With all of the compounds tested there was a significant reduction (p less than or equal to 0.001) of indigenous skin microflora from prescrub levels at both the post-scrub and postoperative points. The two hexachlorophene compounds in general revealed a bacteriostatic effect whereas the triclosan compound and the four iodophors did not. A hexachlorophene compound applied as a foam demonstrated excellent bacteriocidal and bacteriostatic action, was less time-consuming and easier to use than compounds applied as scrubs, and did not alter a low (0.47 per cent) in-use infection rate over a period of three years.