Antimicrobial efficacy and longevity of silver+zeolite incorporating preinsulated ducts installed in real healthcare settings.

OBJECTIVE: The values of microbial growth in the air exiting from the heating, ventilation and air conditioning (HVAC) ducts treated with silver/zeolite have been shown to be lower than those in the air coming out the traditional metal ones. This study aims to verify how long this antimicrobial activity lasts. METHODS: All the tests were performed according to US ASTM E2180-01 and ISO-JIZ 22196 standards. Samples of aluminum cladding panels of different thickness and incorporating silver-zeolite were tested in order to verify their thickness depending antibacterial activity. The same kind of linings samples were analyzed after a simulated and accelerated ageing process. Ag-zeolite incorporating HVAC duct panels linings were tested after years from their installation, in order to verify the maintenance of their bactericidal power during time. RESULTS AND CONCLUSIONS: For laminates containing different amounts of silver+Zeolite it was shown that also in panels with minimum thickness tested, the lowest germicidal effect (GE) found was still very good (GE of 5,76 ULog10). After their wearing and tearing the antimicrobial activity tended to increase passing from 7.2081 to 8.29922 LogUnits in panels 80 microns thick. For still hospital working aluminium foils incorporating Silver/Zeolite on panels installed through 2006 and 2008, the antimicrobial action of zeolite was still firmly present even after two years and three years.The germicidal effect standards were maintained even during time on constant values between 7.477 and 7.086 LogUnits. The persistence of bactericidal efficacy of Ag+zeolite treatment in all the materials used for the construction of HVAC ductworks can be confirmed.

Silver zeolite antimicrobial activity in aluminium heating, ventilation and air conditioning system ducts.

INTRODUCTION: Air pollution in confined environments is a serious health problem, in that most people spend long periods indoors (in homes, offices, classrooms etc.). Some people (children, the elderly, heart disease patients, asthmatic or allergic subjects) are at greater risk because of their conditions of frailty. The growing use of air-conditioning systems in many public and private buildings aggravates this health risk, especially when these systems are not correctly installed or regularly serviced. The aim of our study was to verify the capacity of Ag+ ions to stop the growth of bacteria and moulds inside the ducts of Heating, Ventilation and Air Conditioning system ducts (HVAC) systems when these ducts were lined with active Ag+ ions zeolite-coated panels. MATERIAL AND METHODS: A Y-shaped HVAC model with two branches was used; one branch was made of traditional galvanized iron, as was the whole system, while the other was lined with active Ag+ zeolite-coated polyurethane panels. During the test, samples of dust present inside both ducts were collected and seeded in liquid and solid media to detect bacteria and moulds. The presence of bacteria was also sought in the air emerging from the outlets of both ducts. RESULTS: Tests made on samples of particulate collected from the two different ducts revealed a lower total bacterial load in the samples collected from the Ag+ zeolite-coated duct than in the samples from the traditional Zn galvanized duct. In addition, the values of bacterial load found in the air emerging from the Ag+ ions zeolite-lined duct were 5 times lower than those found in the air from the traditional galvanized iron duct. CONCLUSIONS: The utilization of Ag+ zeolite-coated panels in air-conditioning systems could improve the quality of the emerging air in comparison with traditional installations in galvanized iron. This innovation could prove particularly advantageous in the event of accidents during the installation of air-conditioning systems or of contaminated aerosols coming from outside.

A new electro-optical approach for conductance measurement: an assay for the study of drugs acting on ligand-gated ion channels.

Ligand gated ion channels are involved in many pathophysiological processes and represent a relevant, although challenging, target for drug discovery. We propose an innovative electro-optical approach to their analysis able to derive membrane conductance values from the local membrane potential changes imposed by test current pulses and measured by fast voltage-sensitive fluorescent dyes. We exploited the potential of this proprietary method by developing a drug testing system called "ionChannel Optical High-content Microscope" (ionChannelΩ). This automated platform was validated by testing the responses of reference drugs on cells expressing different ligand-gated ion channels. Furthermore, a double-blind comparison with FLIPR and automated patch-clamp was performed on molecules designed to act as antagonists of the P2RX7 receptor. ionChannelΩ proved highly reliable in all tests, resulting faster and more cost-effective than electrophysiological techniques. Overall, ionChannelΩ is amenable to the study of ligand gated ion channels that are receiving less attention due to limitations in current assays.

Microbiological surveillance of hospital ventilation systems in departments at high risk of nosocomial infections.

The air in hospital wards with patients at high risk (Surgeries, Intensive Care Units and Bone Marrow Transplant Centers) has been surveyed less than the one in Operating Rooms. Therefore in this study we considered useful to verify the microbic contamination of the air of those wards evaluating the consistency of ventilation systems in relation also to the presence and location of HEPA absolute filters. Seven departments of Genoese San Martino Hospital at high risk of infection were taken into account. In there, environmental investigations have been performed by air samplings and by analyzing bacterial and fungal growth on plates after an incubation period. Almost 60% of all samples taken in wards yielded a positive result and the average values of bacterial and aspergillar charges measured at air flow emission openings decisively exceed the ones considered standard in operating rooms. Still, the average values of airborne bacterial charges were significantly higher in those wards equipped with central filters (p < 0.001), while as far as the aspergillar charge is concerned, no statistically relevant differences were noticed. In wards with ventilation system, the bacterial charge value raises from the emission grids to the middle of the room and to the aspiration grids, while the ward not equipped with a ventilation system presents in the middle of the room an average bacterial charge 2 to 10 times higher than the one in other wards. The average values regarding bacterial and aspergillar charges resulted quite high in all the departments surveyed. Nevertheless, if we take into account ventilation systems equipped with absolute filters HEPA located centrally or peripherally, it can be outlined that the air quality from the point of view of both microbic and aspergillar contamination turns out to be decisively better in systems with peripheral filters. Moreover, a compared analysis of the three Hematology wards allows us to infer that the presence of artificial ventilation systems can lower the bacterial and fungal compared with a ward with natural ventilation.

Bacterial load and protein deposits on 15-day versus 1-day disposable hydrophilic contact lenses.

PURPOSE: This study quantified the bacterial load and protein deposits on 1- and 15-day disposable contact lenses after use in normal wearers. METHODS: Sixteen patients were randomly assigned to a 1-day contact lens (1-Day Acuvue) in one eye and to a 15-day contact lens (Acuvue) in the contralateral eye. Only one specified solution was allowed for the care of 15-day lenses. All patients were evaluated every month for 6 months (at times T1, T2, T3, T4, T5, T6). At times T1, T3, and T5, the lenses were removed in a sterile fashion and sent for laboratory quantification of Staphylococcus aureus and Pseudomonas aeruginosa. At T2, T4, and T6, quantification of protein deposits was determined, and at T0 and T6, impression cytology of the conjunctiva was performed. RESULTS: P. aeruginosa was not identified on any lens. At T1, T3, and T5, S. aureus was significantly greater on the 1-day versus 15-day lenses (p < 0.001). In contrast, protein deposits were significantly greater on the 15-day lenses at all time points (T2, T6: p < 0.01; T4: p < 0.05). Impression cytology of the 15-day lens eyes revealed a worsening trend compared to the 1-day lens; however, no statistically significant differences were found between the two groups (p = 0.29). CONCLUSION: Results of this study suggest that the use of cleaning and preservative solutions can alter the ocular surface bacterial environment of the contact lens wearer and that these changes are not a direct consequence of contact lens wear. The bactericidal activity of these solutions could, with time, also affect ocular surface cells, leading to contact lens intolerance and ocular surface disease.

Microwave-assisted preparation of cyclic ketals from a cineole ketone as potential cosmetic ingredients: solvent-free synthesis, odour evaluation, in vitro cytotoxicity and antimicrobial assays.

Some cyclic ketals derived from (+)1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-one were obtained in excellent yields by microwave activation under solvent-free conditions, as a 'green chemistry' procedure. The results obtained using acidic alumina containing 7% p-toluenesulfonic acid, as mineral support, are reported and compared with those obtained by classical methods. The new compounds were tested for their olfactive character and for a potential cosmetic use. In vitro skin cytotoxicity tests were carried out on the most promising compounds, by using NCTC 2544 human keratinocytes as target cells. They all displayed slight cytotoxic effects which were one order of magnitude lower than those found with sodium dodecylsulphate positive control. Two compounds that resulted interesting as toothpaste aromas, were submitted to antimicrobial assays and showed their activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus hominis, Propionibacterium acnes and Candida albicans.

[Hygiene problems associated with characteristics of the sludge from purification plants in Liguria]. / Problemi igienici associati alle caratteristiche dei fanghi provenienti dagli impianti di depurazione in Liguria.

Sludge samples from five municipal sewage treatment plants in Liguria (Italy) were examined periodically during a whole year. Four of them are located in Genova and receive the sewage corresponding respectively to 20,000-53,000-125,000 and 285,000 equivalent inhabitants. The last one is in Chiavari and receives the sewage corresponding to 40,000 equivalent inhabitants. All plants included a preliminary screening treatment, primary sedimentation and a secondary activated sludge process. Sludge was thickened by centrifuge. The bacteriological and chemical characteristics of the sludge after centrifuging (detection and estimation of total and fecal coliforms, fecal streptococci and enumeration and isolation of Salmonella, pH, moisture, total and volatile residue, nitrogen, phosphorus, heavy metals) were measured in order to establish the possibility of land disposal. Dry solids contained on average 34 g/kg total nitrogen and 1,4 g/kg phosphorus. Among heavy metals copper and zinc reached high levels: 544 and 1587 mg/kg of dry solids. Other metals were present at lower concentrations (As 6, Cd 2, Cr 70, Hg 2, Ni 53, pb 416 mg/kg). Comparing these results with those of a research carried out contemporarily in another region (Emilia Romagna) it was observed that in Ligury there is a higher content of copper and bacteria (with an average of 69 Salmonella in 1 g of dry solids). The results showed that sludge produced in the five treatment plants in Ligury (Italy) was apt to be used as fertilizer in soil, but that care has to be taken for what concerns microbial contamination. For what regards the differences among the five sewage treatment plants under observation some heavy metals (arsenic and chromium) reached very high average levels (10-14 mg/kg of arsenic and 70-118 mg/kg of chromium) in the sludge of two of them, which treat the sewage from highly industrialized areas. On the contrary lead and cadmium were present at the same levels in all plants (416 mg/kg of lead and 2 mg/kg of cadmium) with the exception of one (Ge-Quinto) where cadmium was practically absent (0,2 mg/kg). The overall average concentrations of heavy metals resulted definitively lower than maximum concentration proposed by CEE (1986) and by some italian region as Lombardia. Some differences among plants for what regards microbiological parameters were noted only for total coliforms.

Synthesis of ethylammonium iodides of omega-dialkylaminoethyl ethers of 5-(arylmethylene)-1,3,3-trimethyl-2-oxabicyclo [2.2.2.] octan-6-hydroxyimines as potential cosmetic ingredients.

The synthesis of nine quaternary ammonium iodides derived from omega-dialkylaminoethyl ethers of 5-(arylmethylene)-1,3, 3-trimethyl-2-oxabicyclo[2.2.2]octan-6-hydroxyimines, as potential cosmetic ingredients, is described. They are routinely prepared starting from cineole aminoethers by reaction with iodoethane and their physics-chemical data are reported. These substances were studied for their UV absorption and three of these compounds were also submitted to microbiological assays on five test organisms. The substances have their UV absorption maxima at 284-321 nm, and one compound is active on Staphylococcus aureus, Streptococcus faecalis and Candida albicans. These preliminary findings seem to indicate that some of these compounds could be considered as potential UV sunscreens; one compound, having a moderate antimicrobial activity, could be considered a potential active compound in cosmetics as deodorants, toothpastes, mouthwashes and other oral care products.

Seroprevalence of bactericidal antibody against Neisseria meningitidis serogroup C in pre-vaccinal era: the Italian epidemiological scenario.

Meningococcal disease is particularly severe. The case-fatality rate is 7.78% in Europe and 10-14% in the USA. This paper reports the results of a sero-epidemiological study in Italy on meningitis due to Meningococcus C before the introduction of the monovalent conjugate vaccine. In 2003-2004, a total of 577 sera were collected in 17 of the 20 Italian Regions. Serum Bactericidal Assay (SBA) was performed by using rabbit complement serum according to standardized SBA. The results showed that the percentages of protected subjects decreased from 6 to 12 months of age, increased from 1 to 4 years, decreased again until the age of 8 years and from 13 to 16 years, and were particularly high in 9- and 17-year-old subjects. The geometric mean titre of bactericidal antibodies (SBAbs GMT) was low in subjects under 1 year of age, significantly increased in 1-9-year-old children and decreased in adolescents and young adults. Finally, in each one-year age-group, low levels of antibodies were observed in subjects under 1 year of age, in 10-year-old subjects and in 14-16-year-old adolescents. High titres were observed in 3-, 8-, 9- and 17-year-old subjects. Our results therefore indicate that meningococcus C has the highest probability of spreading among 1-4, 8-10 and 14-17-year-old subjects in Italy.