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At least 55 records · Page 3Linked to original sources
PubMed1988

[New heterocyclic derivatives of benzimidazole with germicidal activity. V. Synthesis and activity of new derivatives of di-2-benzimidazolyl-2,5-furan].

In continuation of the research in the field of germicidal and antimycotic agents, the synthesis of 14 new derivatives of di-2-benzimidazolyl-2,5-furan is described. These derivatives are differently substituted (R not equal to R') in the position 5 of the two benzene rings. These new compounds showed no germicidal or fungicidal activity, when tested on different cultures. New compounds are under investigation.

Anti-Infective Agents↗
PubMed1983

Pharmacokinetics of Alcide, a germicidal compound in rat.

Alcide is a germicidal compound which is currently being used as a liquid sterilizer. This agent has the ability to kill a wide range of bacteria, viruses and fungi in vitro within 1 min. The active ingredients in this sterilizer are sodium chlorite and lactic acid. The kinetics of 36Cl-labelled liquid Alcide were studied in rats. After oral administration, the peak plasma level was obtained in 8 h. The half life for 36Cl absorption from plasma was 8.03 h, corresponding to a rate constant of 0.086 h-1, while the half life for 36Cl elimination from plasma was 48.02 h, corresponding to a rate constant of 0.014 h-1. At 144 h, radioactivity was highest in plasma followed by lung, kidney, skin, bone marrow, stomach, ovary, duodenum, ileum, spleen, fat, brain, liver and carcass. The greatest amount of activity in whole blood was present in plasma. Subcellular distribution revealed that 85% of the activity in the liver homogenate resided in the cytosol. Seventy per cent of total activity in plasma was located in the trichloroacetic acid (TCA) supernant, with 30% bound to the precipitated protein fraction. Urinary excretion accounted for most of the 36Cl eliminated. Radioactivity was excreted as chloride and chlorite in urine.

Animals↗
PubMed1986

Effect of a benzoic acid-detergent germicide on denture-borne Candida albicans.

Benzoic acid combined with a detergent was used to safely and effectively decontaminate dentures colonized with Candida albicans. Surface decontamination was accomplished by soaking the dentures in the germicide solution for a period of 6 hours to overnight. Decontamination may occur in as little as 10 minutes when soaking is combined with ultrasonic enhancement.

Benzoates↗
PubMed2003

Effect of ultraviolet germicidal lights installed in office ventilation systems on workers' health and wellbeing: double-blind multiple crossover trial.

BACKGROUND: Workers in modern office buildings frequently have unexplained work-related symptoms or combinations of symptoms. We assessed whether ultraviolet germicidal irradiation (UVGI) of drip pans and cooling coils within ventilation systems of office buildings would reduce microbial contamination, and thus occupants' work-related symptoms. METHODS: We undertook a double blind, multiple crossover trial of 771 participants. In office buildings in Montreal, Canada, UVGI was alternately off for 12 weeks, then turned on for 4 weeks. We did this three times with UVGI on and three times with it off, for 48 consecutive weeks. Primary outcomes of self-reported work-related symptoms, and secondary outcomes of endotoxin and viable microbial concentrations in air and on surfaces, and other environmental covariates were measured six times. FINDINGS: Operation of UVGI resulted in 99% (95% CI 67-100) reduction of microbial and endotoxin concentrations on irradiated surfaces within the ventilation systems. 771 participants appeared to remain masked, and reported no adverse effects. On the basis of within-person estimates, use of UVGI was associated with significantly fewer work-related symptoms overall (adjusted odds ratio 0.8 [95% CI 0.7-0.99]), as well as respiratory (0.6 [0.4-0.9]) and mucosal (0.7 [0.6-0.9]) symptoms than was non-use. Reduction of work-related mucosal symptoms was greatest among atopic workers (0.6 [0.5-0.8]), and never-smokers (0.7 [0.5-0.9]). With UVGI on, never-smokers also had large reduction of work-related respiratory (0.4 [0.2-0.9]), and musculoskeletal symptoms (0.5 [0.3-0.9]). INTERPRETATION: Installation of UGVI in most North American offices could resolve work-related symptoms in about 4 million employees, caused by microbial contamination of heating, ventilation, and air-conditioning systems. The cost of UVGI installation could in the long run prove cost-effective compared with the yearly losses from absence because of building-related illness.

Adult↗
PubMed2005

(E)-5-[2-(methoxycarbonyl)ethenyl]cytidine as a chemical actinometer for germicidal UV radiation.

(E)-5-[2-(Methoxycarbonyl)ethenyl]cytidine (S) was examined for use as a chemical actinometer for germicidal UV radiation. Its photoproduct, 3-beta-D-ribofuranosyl-2,7-dioxopyrido[2,3-d]pyrimidine (P), is strongly fluorescent with excitation and emission maxima at 330 and 385 nm, respectively. Experiments were conducted to characterize the dynamic behavior of aqueous solutions of S and P when subjected to UV radiation. UV sources used for these experiments included a low-pressure mercury lamp, a XeBr excimer lamp, and a KrCI excimer lamp; all three sources were mounted in collimating devices to provide incident beams that could be easily and accurately characterized by radiometry. These three sources each yielded essentially monochromatic outputwith characteristic wavelengths of 254, 282, and 222 nm, respectively. At practical concentrations, it was found that the absorbance of the actinometer solution was neither high enough to make the actinometer solutions optically opaque nor low enough to be optically transparent to UV. In addition, the photoproduct displayed a molar absorption coefficient that was similar in magnitude to that of the parent compound, thereby resulting in competitive absorption of UV energy between Sand Pduring irradiation. For purposes of evaluation of the results of irradiation, a mathematical model was developed to accountforthe nonideal optical characteristics of the system. The model is based on a description of local photochemical kinetics; predictions of overall reactor performance were developed by spatial and temporal integration of model results. The model was used to analyze the dynamic behavior of actinometer solutions during UV irradiation and to estimate the quantum yield for photoproduction of Pfrom S. This modeling approach is potentially applicable to other photochemical processes in which multiple compounds are present that absorb photoactive radiation; however, general application of this modeling approach to photochemical reactor systems will require inclusion of othertermsto describe relevanttransport behavior within the system.

Cytidine↗
PubMed2005

Impact of environmental factors on efficacy of upper-room air ultraviolet germicidal irradiation for inactivating airborne mycobacteria.

This study evaluated the efficacy of an upper-room air ultraviolet germicidal irradiation (UVGI) system for inactivating airborne bacteria, which irradiates the upper part of a room while minimizing radiation exposure to persons in the lower part of the room. A full-scale test room (87 m3), fitted with a UVGI system consisting of 9 louvered wall and ceiling fixtures (504 W all lamps operating) was operated at 24 and 34 degrees C, between 25 and 90% relative humidity, and at three ventilation rates. Mycobacterium parafortuitum cells were aerosolized into the room such that their numbers and physiologic state were comparable both with and without the UVGI system operating. Airborne bacteria were collected in duplicate using liquid impingers and quantified with direct epifluorescent microscopy and standard culturing assay. Performance of the UVGI system degraded significantly when the relative humidity was increased from 50% to 75-90% RH, the horizontal UV fluence rate distribution was skewed to one side compared to being evenly dispersed, and the room air temperature was stratified from hot at the ceiling to cold at the floor. The inactivation rate increased linearly with effective UV fluence rate up to 5 microW cm(-2); an increase in the fluence rate above this level did not yield a proportional increase in inactivation rate.

Air Microbiology↗
PubMed1999

The efficacy of three common hospital liquid germicides to inactivate Cryptosporidium parvum oocysts.

We evaluated three commonly used hospital disinfectants against three concentrations of Cryptosporidium parvum oocysts (1.5 x 10(6), 1.5 x 10(5), 1.5 x 10(4)). A 10% phenol product, a 10% povidone-iodine product and a 2.5% glutaraldehyde product were tested against Cryptosporidium parvum oocysts without organic load. In-vitro excystation was used to determine viability and a cell culture assay was used to determine infectivity of germicide-treated oocysts. A 2.5% glutaraldehyde product was the most effective in halting excystation of sporozoites and infection in cell monolayers. However, this occurred only at the longest exposure time of 10 h and with the lowest concentration of oocysts (1.5 x 10(4)). The 10% phenol product and the 10% povidone-iodine product also decreased excystation, but were unable to halt infection. Although the ability of C. parvum to with-stand chemical treatment is well known, the ability of oocysts to remain viable and infectious after a 10 h treatment in glutaraldehyde is cause for concern. Endoscopic equipment that may come into contact with these organisms cannot be immersed into glutaraldehyde for this length of time due to its corrosive nature. Thus, the results of this research are cause for concern in hospital disinfection units.

Animals↗
PubMed2001

Preventing the spread of hepatitis B and C viruses: where are germicides relevant?

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are the most prevalent bloodborne pathogens. Infections caused by these organisms can become chronic and may lead to liver cirrhosis and carcinoma. Limited chemotherapy is now available, but only HBV can be prevented through vaccination. Both viruses are enveloped and relatively sensitive to many physical and chemical agents; their ability to survive in the environment may not be as high as often believed. As a result, their spread occurs mainly through direct parenteral or percutaneous exposure to tainted body fluids and tissues. Careful screening of and avoiding contact with such materials remain the most effective means of protection. Nevertheless, the indirect spread of these viruses, although much less common, can occur when objects that are freshly contaminated with tainted blood enter the body or contact damaged skin. Germicidal chemicals are important in the prevention of HBV and HCV spread through shared injection devices, sharps used in personal services (such as tattooing and body piercing), and heat-sensitive medical/dental devices (such as flexible endoscopes) and in the cleanup of blood spills. Microbicides in vaginal gels may also interrupt their transmission. General-purpose environmental disinfection is unlikely to play a significant role in the prevention of the transmission of these viruses. Testing of low-level disinfectants and label claims for such products against HBV and HCV should be discouraged. Both viruses remain difficult to work with in the laboratory, but closely related animal viruses (such as the duck HBV) and the bovine viral diarrhea virus show considerable promise as surrogates for HBV and HCV, respectively. Although progress in the culturing of HBV and HCV is still underway, critical issues on virus survival and inactivation should be addressed with the use of these surrogates.

Animals↗
PubMed1998

Method for Evaluating Germicidal Ultraviolet Inactivation of Biocontaminated Surfaces.

Safety issues related to work-site conditions often deal with potential worker exposure to infectious airborne microorganisms due to their dissemination in indoor air and contamination of surfaces. Germicidal ultraviolet (GUV) radiation is used in health-care settings and other occupational environments for microbial inactivation. In this study, a new methodology for determining the efficiency of GUV microbial inactivation of surfaces was developed and evaluated. The method utilizes identical chambers in which test microorganisms are irradiated on agar surfaces at different humidity and irradiation intensity levels. The effects of GUV intensity and exposure time on microbial inactivation were examined for Micrococcus luteus and Serratia marcescens. It was found that at low humidity levels (20-25%) both organisms can be inactivated with at least 95% efficiency if the GUV intensity exceeds 50 μW/cm2 for at least 3-5 min (corresponding to a dose of ~ 10 mJ/cm2). The radiation dose needed for effective inactivation of S. marcescens, as measured by a UV meter near the microbial sample, was found not to be affected by the humidity level, whereas that of M. luteus increased at higher humidities. The findings of this study can be used to determine sufficient GUV inactivation doses for occupational environments with various microbial contaminations.

UV inactivation↗
PubMed2006

UV air cleaners and upper-room air ultraviolet germicidal irradiation for controlling airborne bacteria and fungal spores.

In-room air cleaners (ACs) and upper-room air ultraviolet germicidal irradiation (UVGI) are engineering control technologies that can help reduce the concentrations of airborne bacteria and fungal spores in the indoor environment. This study investigated six different types of ACs and quantified their ability to remove and/or inactivate airborne bacteria and fungal spores. Four of the air cleaners incorporated UV lamp(s) into their flow path. In addition, the efficacy of combining ACs with upper-room air UVGI was investigated. With the ventilation system providing zero or six air changes per hour, the air cleaners were tested separately or with the upper-room air UVGI system in operation in an 87-m3 test room. Active bacteria cells and fungal spores were aerosolized into the room such that their numbers and physiologic state were comparable both with and without air cleaning and upper-room air UVGI. In addition, the disinfection performance of a UV-C lamp internal to one of the ACs was evaluated by estimating the percentage of airborne bacteria cells and fungal spores captured on the air filter medium surface that were inactivated with UV exposure. Average airborne microbial clean air delivery rates (CADRm) varied between 26-981 m3 hr-1 depending on the AC, and between 1480-2370 m3 hr-1, when using air cleaners in combination with upper-room air UVGI. Culturing, direct microscopy, and optical particle counting revealed similar CADRm. The ACs performed similarly when challenged with three different microorganisms. Testing two of the ACs showed that no additional air cleaning was provided with the operation of an internal UV-C lamp; the internal UV-C lamps, however, inactivated 75% of fungal spores and 97% of bacteria cells captured in the air filter medium within 60 min.

Aerosols↗
PubMed1989

Germicidal effectiveness of Dialox, a new stable peroxyacetic acid solution, in the re-use of high-flux dialysers.

In this study we evaluate the effectiveness of a newly available peroxyacetic acid solution (Dialox) as a disinfecting agent in the re-use of highly permeable dialysers. The germicidal properties of Dialox were tested in an in vitro trial on previously used haemodiafilters (HF80, Fresenius) highly contaminated with Pseudomonas aeruginosa, Mycobacterium smegmatis or sporulated Bacillus cereus. Complete freedom from bacterial contamination was observed 5 min after the reprocessing treatment on a Renatron reprocessing machine, using the currently marketed Dialox concentrate.

Acetates↗
PubMedDate not supplied

The application of ultraviolet germicidal irradiation to control transmission of airborne disease: bioterrorism countermeasure.

Bioterrorism is an area of increasing public health concern. The intent of this article is to review the air cleansing technologies available to protect building occupants from the intentional release of bioterror agents into congregate spaces (such as offices, schools, auditoriums, and transportation centers), as well as through outside air intakes and by way of recirculation air ducts. Current available technologies include increased ventilation, filtration, and ultraviolet germicidal irradiation (UVGI) UVGI is a common tool in laboratories and health care facilities, but is not familiar to the public, or to some heating, ventilation, and air conditioning engineers. Interest in UVGI is increasing as concern about a possible malicious release of bioterror agents mounts. Recent applications of UVGI have focused on control of tuberculosis transmission, but a wide range of airborne respiratory pathogens are susceptible to deactivation by UVGI. In this article, the authors provide an overview of air disinfection technologies, and an in-depth analysis of UVGI-its history, applications, and effectiveness.

Air Microbiology↗
PubMed2001

Estimation of tuberculosis risk and incidence under upper room ultraviolet germicidal irradiation in a waiting room in a hypothetical scenario.

Environmental control measures (ventilation, high-efficiency particulate air filtration, and upper room ultraviolet germicidal irradiation [UVGI]) are recommended to effectively control tuberculosis (TB) transmission from unsuspected TB patients in high-risk settings, but the effectiveness of their use is not often clear. This study presents a simulation model for a hypothetical hospital waiting room, in which the number of susceptible immunocompetent people in the waiting room follows a Poisson distribution (M = 5) in either low (annual number of TB patients = 5) or high TB risk settings (annual number of TB patients = 50), and used the model to evaluate the reduction of TB transmission risk by upper room UVGI. An exponential dose-response model was used for TB transmission and a two-zone model was used for evaluating the effect of upper room UVGI. Upper room UVGI reduced TB risk by 1.6-fold at 3 microW/cm2 UV irradiance in the upper room in the low TB risk setting and by 4.1-fold at 15 microW/cm2 UV irradiance in the upper room in the high TB risk setting. Use of upper room UVGI also reduced the mean annual new infection rate from 2.2 to 1.3 infections per year at 3 microW/cm2 and to 0.6 infections per year at 15 microW/cm2 in our hypothetical high-risk settings. The effect of upper room UVGI was sensitive to both vertical air velocity (air mixing) and UV irradiance level. Results from partitioning variability indicate that most variability of TB transmission risk came from waiting time in our hypothetical hospital.

Computer Simulation↗
PubMed1997

Control of the amount of free molecular iodine in iodine germicides.

Horseradish peroxidase has been used to generate iodine compositions that comprised principally free molecular iodine. The concentration of free molecular iodine in these enzyme-based compositions ranged from 44 to 63% of the thiosulphate titratable iodine; this is substantially higher than the corresponding value for the povidone-iodine preparation betadine. The biocidal efficacy of these compositions was proportional to the concentration of free molecular iodine. Iodine compositions with relatively low total iodine concentrations but high levels of free molecular iodine (20-175 ppm) killed Staphylococcus aureus and spores of Bacillus subtilis more rapidly than betadine. The effects of normal saline and these enzyme-based iodine compositions on the rate of epidermal regeneration in superficial swine wounds were comparable. These results suggest that an effective germicide containing a high level of molecular iodine need not be irritating or toxic.

Animals↗
PubMed1991

Quantitative assessment of the germicidal efficacy of ultrasonic energy.

Propagated (free-field) ultrasonic energy at a frequency of 26 kHz was used to expose aqueous suspensions of bacteria (Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa), fungus (Trichophyton mentagrophytes), and viruses (feline herpesvirus type 1 and feline calicivirus) to evaluate the germicidal efficacy of ultrasound. There was a significant effect of time for all four bacteria, with percent killed increasing with increased duration of exposure, and a significant effect of intensity for all bacteria except E. coli, with percent killed increasing with increased intensity level. There was a significant reduction in fungal growth compared with that in the controls, with decreased growth with increased ultrasound intensity. There was a significant reduction for feline herpesvirus with intensity, but there was no apparent effect of ultrasound on feline calicivirus. These results suggest that ultrasound in the low-kilohertz frequency range is capable to some degree of inactivating certain disease agents that may reside in water. The physical mechanism of inactivation appears to be transient cavitation.

Bacteria↗
PubMed2004

Size and UV germicidal irradiation susceptibility of Serratia marcescens when aerosolized from different suspending media.

Experimental systems have been built in laboratories worldwide to investigate the influence of various environmental parameters on the efficacy of UV germicidal irradiation (UVGI) for deactivating airborne microorganisms. It is generally recognized that data from different laboratories might vary significantly due to differences in systems and experimental conditions. In this study we looked at the effect of the composition of the suspending medium on the size and UVGI susceptibility of Serratia marcescens in an experimental system built in our laboratory. S. marcescens was suspended in (i) distilled water, (ii) phosphate buffer, (iii) 10% fetal calf serum, (iv) phosphate-buffered saline (saline, 0.8% sodium chloride), and (v) synthetic saliva (phosphate-buffered saline with 10% fetal calf serum). At low humidity (36%), S. marcescens suspended in water-only medium was the most susceptible to UVGI, followed by those in serum-only medium. The count median diameters (CMDs) for culturable particles from water-only and serum-only media were 0.88 and 0.95 micro m, respectively, with the measurements based on their aerodynamic behavior. The bacteria suspended in phosphate buffer, synthetic saliva, and phosphate-buffered saline had similar UVGI susceptibility and CMD at 1.0, 1.4, and 1.5 micro m, respectively. At high humidity (68%) the CMD of the particles increased by 6 to 16%, and at the same time UVGI susceptibility decreased, with the magnitude of decrease related to the type of suspending medium. In conclusion, the choice of suspending medium influenced both size and UVGI susceptibility of S. marcescens. These data are valuable for making comparisons and deciding on the use of an appropriate medium for various applications.

Aerosols↗