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- Disinfection of Rigid Nasal Endoscopes Following In Vitro Contamination With Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae. [JOURNAL ARTICLE]
- JAMA Otolaryngol Head Neck Surg 2013 May 16.:1-5.
IMPORTANCE If not adequately cleaned, rigid nasal endoscopes (RNEs) have the potential to cause iatrogenic cross-contamination.
OBJECTIVETo test the efficacy of various disinfection methods in reducing bacterial load on RNEs in vitro. DESIGN AND SETTING In vitro model. INTERVENTIONS Staphylococcus aureus, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae contamination was separately induced on RNEs in vitro. Two experimental sets were completed. The RNEs were disinfected using the following protocols: 30-second scrub with antimicrobial soap (ABS) and water, 30-second scrub with 70% isopropyl alcohol (IA), 30-second scrub with ABS followed by 30-second scrub with IA, 30-second scrub with germicidal cloth, isolated 5-minute soak in an enzymatic soap solution, 5- and 10-minute soaks in ortho-phthalaldehyde, 0.55%, solution (Cidex OPA), and isolated 30-second rinse with tap water, all with 30-second precleaning and postcleaning rinses with tap water. Two sets of experiments (experiment sets A and B) were carried out with a 30-second tap water rinse after inoculation of each RNE. This was followed by immediate cleaning in set A and a 1-hour air-dry delay in set B. Otherwise there were no differences in the disinfection protocols between sets for each method noted. MAIN OUTCOMES AND MEASURES Effectiveness of various disinfection protocols in cleaning rigid nasal endoscopes experimentally inoculated with bacteria commonly found in the upper aerodigestive tract. Positive cultures following disinfection indicated ineffective or incomplete disinfection.
RESULTSMost cleaning methods were effective in eliminating S aureus, S pneumoniae, and H influenzae from the scopes following experimental contamination. Continued growth of P aeruginosa was found after all of the disinfection trials in experiment set A with the exception of a 10-minute immersion in Cidex OPA, and in set B except for the 10-minute Cidex OPA immersion and ABS plus IA trials.
CONCLUSIONSAND RELEVANCE Most cleaning methods used in our trials appear to properly disinfect RNEs after in vitro inoculation with S aureus, S pneumoniae, and H influenzae. However, it appears that disinfectants may be less effective in cleaning rigid scopes experimentally inoculated with P aeruginosa. There is a paucity of published data regarding cross-contamination during rigid nasal endoscopy, and these results should guide future studies and to some extent practice to avoid iatrogenic spread of contamination.
- Nano-silica fabricated with silver nanoparticles: antifouling adsorbent for efficient dye removal, effective water disinfection and biofouling control. [JOURNAL ARTICLE]
- Nanoscale 2013 May 16.
A nano-silica-AgNPs composite material is proposed as a novel antifouling adsorbent for cost-effective and ecofriendly water purification. Fabrication of well-dispersed AgNPs on the nano-silica surface, designated as NSAgNP, has been achieved through protein mediated reduction of silver ions at ambient temperature for development of sustainable nanotechnology. The coated proteins on AgNPs led to the formation of stable NSAgNP and protected the AgNPs from oxidation and other ions commonly present in water. The NSAgNP exhibited excellent dye adsorption capacity both in single and multicomponent systems, and demonstrated satisfactory tolerance against variations in pH and dye concentration. The adsorption mainly occurred through electrostatic interaction, though π-π interaction and pore diffusion also contributed to the process. Moreover, the NSAgNP showed long-term antibacterial activity against both planktonic cells and biofilms of Gram-negative Escherichia coli and Pseudomonas aeruginosa. The antibacterial activity of AgNPs retarded the initial attachment of bacteria on NSAgNP and thus significantly improved the antifouling properties of the nanomaterial, which further inhibited biofilm formation. Scanning electron and fluorescence microscopic studies revealed that cell death occurred due to irreversible damage of the cell membrane upon electrostatic interaction of positively charged NSAgNP with the negatively charged bacterial cell membrane. The high adsorption capacity, reusability, good tolerance, removal of multicomponent dyes and E. coli from the simulated contaminated water and antifouling properties of NSAgNP will provide new opportunities to develop cost-effective and ecofriendly water purification processes.
- Molecular Mechanism of Metal-independent Decomposition of Lipid Hydroperoxide 13-HPODE by Halogenated Quinoid Carcinogens. [JOURNAL ARTICLE]
- Free Radic Biol Med 2013 May 13.
Halogenated quinones are a class of carcinogenic intermediates and newly identified chlorination disinfection byproducts in drinking water. 13-Hydroperoxy-9,11-octadecadienoic acid (13-HPODE) is the most extensively studied endogenous lipid hydroperoxide. Although it is well known that the decomposition of 13-HPODE can be catalyzed by transition metal ions, it is not clear whether halogenated quinones could enhance its decomposition independent of metal ions, and if so, what are the unique characteristics and similarities? Here we show that 2,5-dichloro-1,4-benzoquinone (DCBQ) could markedly enhance the decomposition of 13-HPODE and formation of the reactive lipid alkyl radicals such as pentyl and 7-carboxyheptyl radicals, and the genotoxic 4-hydroxy-2-nonenal (HNE), through the complementary application of ESR spin-trapping, HPLC-MS and GC-MS methods. Interestingly, two chloroquinone-lipid alkoxyl conjugates were also detected and identified from the reaction between DCBQ and 13-HPODE. Analogous results were observed with other halogenated quinones. This represents the first report that halogenated quinoid carcinogens can enhance the decomposition of the endogenous lipid hydroperoxide 13-HPODE and formation of reactive lipid alkyl radicals and genotoxic HNE via a novel metal-independent nucelophilic substitution coupled with homolytic decomposition mechanism, which may partly explain their potential genotoxicity and carcinogenicity.
- [Response and evaluation of the disinfection effects on an anthrax outbreak inhuman being and cattle in Guizhou]. [Journal Article]
- Zhonghua Liu Xing Bing Xue Za Zhi 2013 Jan; 34(1):104-5.
- Incineration or autoclave? A comparative study in isfahan hospitals waste management system (2010). [Journal Article]
- Mater Sociomed 2013 Mar; 25(1):48-51.
Medical wastes are among hazardous wastes and their disposal requires special methods prior to landfilling. Medical wastes are divided into infected and non-infected wastes and the infected wastes require treatment. Incineration is one of the oldest methods for treatment of medical wastes, but their usage have faced wide objections due to emission of hazardous gases such as CO2 and CO as well as Carcinogenic gases such as Dioxins and Furans which are generated as a result of incomplete combustion of compositions like PVCs. Autoclave is one the newest methods of medical wastes treatment which works based on wet disinfection.The statistical population in this descriptive, comparative study includes hospitals located in Isfahan city and the sample hospitals were selected randomly. To environmentally evaluate the Autoclave method, TST (time, steam, temperature) and Spore tests were used. Also, samples were made from incinerator's stack gases and their analyses results were compared with WHO standards.TST and spore tests results were negative in all cases indicating the success of treatment process. The comparison of incinerator's stack gases with WHO standards showed the high concentration of CO in some samples indicating the incomplete combustion. Also, the incineration efficiency in some cases was less than 99.5 percent, which is the efficiency criterion according to the administrative regulations of wastes management law of Iran. No needle stick was observed in Autoclave method during the compaction of bags containing wastes, and the handlers were facing no danger in this respect. The comparison of costs indicated that despite higher capital investment for purchasing autoclave, its current costs (e.g. maintenance, etc) are much less than the incineration method.Totally, due to inappropriate operation of incinerators and lack of air pollution control devices, the use of incinerators doesn't seem rational anymore. Yet, despite the inefficiency of autoclaves in treatment of bulky wastes such as Anatomical wastes, their usage seems logic considering the very low amounts of such wastes. Also, considering the amount of generated wastes in Isfahan hospitals, a combination of centralized and non-centralized autoclaves is recommended for treatment of infected wastes. Mobile autoclaves may also be considered according to technical and economical conditions. It must not be forgotten that the priority must be given to the establishment of waste management systems particularly to personnel training to produce less wastes and to well separate them.
- Ferrate(VI): a novel oxidant for degradation of cationic surfactant - cetylpyridinium bromide. [Journal Article]
- Water Sci Technol 2013 May; 67(10):2184-9.
Ferrate(VI) is an efficient multi-functional water treatment reagent that has several novel properties, such as strong oxidation, absorption, flocculation, disinfection and deodorization. The removal of cationic surfactants based on ferrate (K2FeO4) was performed in the case of cetylpyridinium bromide (CPB). The inﬂuence of operating variables on the mineralization efﬁciency was studied as a function of ferrate dosage, initial pH and reaction time. Total organic carbon (TOC), UV and infrared spectra were performed to gain a better understanding of the degradation process. Results show that the optimal treatment conditions are as follows, solution initial pH is over 5, oxidation time is 5 min and ferrate dosage is 1.5 times that of CPB. The removal efficiency of CPB above 99% and TOC removal percentage of 91.3% can be achieved in minutes. The reaction of CPB with K2FeO4 responds to a second-order kinetic law.
- Intracellular Organic Matter from Cyanobacteria as a Precursor for Carbonaceous and Nitrogenous Disinfection Byproducts. [JOURNAL ARTICLE]
- Environ Sci Technol 2013 May 15.
The formation of total organic halogen (TOX), carbonaceous disinfection byproducts (DBPs) (trihalomethanes (THMs) and haloacetic acids (HAAs)) and nitrogenous DBPs (trichloronitromethane (TCNM) or chloropicrin, haloacetonitriles (HANs) and nitrosamines) was examined during the chlorination or chloramination of intracellular organic matter (IOM) extracted from Microcystis aeruginosa, Oscillatoria sp. (OSC), and Lyngbya sp. (LYN). The percentage of unknown TOX (22-38%) during chlorination indicated the majority of DBPs were identified among THMs, HAAs, TCNM, and HANs. Bromide was readily incorporated into DBPs with speciation shifting slightly from dihalogenated species to trihalogenated species. During formation potential testing with chloramines, nitrosamine yields from IOM were measured for N-nitrosodimethylamine (NDMA, 10-52 ng/mgC), N-nitrosopyrrolidine (NPYR, 14 ng/mgC), N-nitrosopiperidine (NPIP, 3.7-5.5 ng/mgC), and N-nitrosomethylethylamine (NMEA, 2.1-2.6 ng/mgC). When IOM was added to a natural water matrix, the nitrosamine yields were not realized likely due to competition from natural organic matter. Ozonation increased NDMA and NMEA formation and reduced NPYR and NPIP formation during subsequent chloramination. In addition, ozone oxidation of IOM formed detectable concentration of aldehydes, which may contribute to DBP formation. Finally, bioluminescence-based test results showed that >99% of the IOM extracted from OSC and LYN was biodegradable. Therefore, a biological treatment process could minimize this source of DBP precursor material during drinking water treatment.
- Magnetically ultraresponsive nanoscavengers for next-generation water purification systems. [Journal Article]
- Nat Commun 2013.:1866.
The development of sustainable, robust and energy efficient water purification technology is still challenging. Although use of nanoparticles is promising, methods are needed for their efficient recovery post treatment. Here we address this issue by fabrication of magnetically ultraresponsive 'nanoscavengers', nanoparticles containing synthetic antiferromagnetic core layers and functional capping layers. When dispersed in water, the nanoscavengers efficiently interact with contaminants to remove them from the water. They are then quickly collected (<5 min) with a permanent magnet, owing to their magnetically ultraresponsive core layers. Specifically, we demonstrate fabrication and deployment of Ag-capped nanoscavengers for disinfection followed by application of an external magnetic field for separation. We also develop and validate a collision-based model for pathogen inactivation, and propose a cyclical water purification scheme in which nanoscavengers are recovered and recycled for contaminant removal.
- Speciation and formation of iodinated trihalomethane from microbially derived organic matter during the biological treatment of micro-polluted source water. [JOURNAL ARTICLE]
- Chemosphere 2013 May 11.
Water sources are micro-polluted by the increasing range of anthropogenic activities around them. Disinfection byproduct (DBP) precursors in water have gradually expanded from humic acid (HA) and fulvic acid to other important sources of potential organic matter. This study aimed to provide further insights into the effects of microbially derived organic matter as precursors on iodinated trihalomethane (I-THM) speciation and formation during the biological treatment of micro-polluted source water. The occurrence of I-THMs in drinking water treated by biological processes was investigated. The results showed for the first time that CHCl2I and CHBrClI are emerging DBPs in China. Biological pre-treatment and biological activated carbon can increase levels of microbes, which could serve as DBP precursors. Chlorination experiments with bovine serum albumin (BSA), starch, HA, deoxyribonucleic acid (DNA), and fish oil, confirmed the close correlation between the I-THM species identified during the treatment processes and those predicted from the model compounds. The effects of iodide and bromide on the I-THM speciation and formation were related to the biochemical composition of microbially derived organic precursors. Lipids produced up to 16.98μgL(-1) of CHCl2I at an initial iodide concentration of 2mgL(-1). HA and starch produced less CHCl2I at 3.88 and 3.54μgL(-1), respectively, followed by BSA (1.50μgL(-1)) and DNA (1.35μgL(-1)). Only fish oil produced I-THMs when iodide and bromide were both present in solution; the four other model compounds formed brominated species.
- Improving hand hygiene compliance in the anesthesia working room work area: More than just more hand rubs. [JOURNAL ARTICLE]
- Am J Infect Control 2013 May 11.