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PubMed2005

Bacterial contamination of central venous catheters during insertion: a double blind randomised controlled trial.

Static electricity within sterile packaging may result in bacterial contamination of central venous catheters (CVCs) prior to insertion. To prevent this, some surgeons inject saline into the pack before opening it. This trial was designed to determine the effect of this procedure. A double blind randomised controlled trial of 47 CVCs comparing injection of 2 ml of sterile saline into the pack prior to opening with no injection was performed. Five centimetre lengths cut from the tip of the catheter before and after subcutaneous tunnelling were sent for microbiological culture. Eight catheters (17%) showed evidence of bacterial contamination prior to insertion into the vein. Two (4.2%) were contaminated prior to tunnelling and seven (14.9%) afterwards. One catheter was contaminated before and after tunnelling. All but one of the contaminating bacteria were coagulase negative staphylococci. There was no significant difference in the contamination rate between catheters from packs that had been injected (5/25) and those that had not (3/22), P = 0.56. Just under one-fifth of the catheters were contaminated with bacteria prior to insertion into the vein but this was not influenced by prior injection of saline into the pack. We conclude that there is no evidence to support the practice of injecting the catheter pack prior to opening.

Adolescent↗

PubMed1993

Microbiologic contamination during dental radiographic film processing.

This study investigated microbiologic contamination of an automatic dental radiograph processor and daylight loader during a week of simulated clinical use. Pure cultures of Candida albicans, Streptococcus pneumoniae, Staphylococcus aureus, or Klebsiella pneumoniae were used to contaminate 320 vinyl intraoral radiograph packets. Each end of the films was deliberately contaminated during opening. These films and 24 uncontaminated control films were processed. Daylight loader ports, inlet and outlet rollers, fixer and developer samples, and 12 processed films were cultured daily. To simulate a weekend, the processor sites were cultured during 72 hours of inactivity after the contaminated runs. The results showed that contamination of the processor and daylight loader occurred and remained even after 48 hours of inactivity. Films remained contaminated after processing. In addition, cross-contamination of films occurred in the processor.

Candida albicans↗

PubMed1994

Chlorinated hydrocarbon contaminants in arctic marine mammals.

By 1976, the presence of chlorinated hydrocarbon contaminants (CHCs) had been demonstrated in fur seal (Callorhinus ursinus), ringed seal (Phoca hispida), hooded seal (Cystophora cristata), bearded seal (Erignathus barbatus), walrus (Obdobenus rosmarus divergens), beluga (Delphinapterus leucas), porpoise (Phocoena phocoena) and polar bear (Ursus maritimus) in various parts of the Arctic. In spite of this early interest, very little subsequent research on contaminants in Arctic marine mammals was undertaken until the mid-1980s. Since that time, there has been an explosion of interest, resulting in a much expanded data base on contaminants in Arctic marine mammals. Except in the Russian Arctic, data have now been obtained on the temporospatial distribution of PCBs and other contaminants in ringed seal, beluga and polar bear. Contaminants in narwhal (Monodon monoceros) have also now been measured. On a fat weight basis, the sum of DDT-related compounds (S-DDT) and PCB levels are lowest in walrus (< 0.1 microgram/g), followed by ringed seal, (0.1-1 microgram/g range). Levels are an order of magnitude higher in beluga and narwhal (1-10 micrograms/g range). It appears that metabolism and excretion of S-DDT and PCBs may be less efficient in cetaceans, leading to greater biomagnification. Polar bears have similar levels of PCBs as cetaceans (1-10 micrograms/g), but with a much simpler congener pattern. DDE levels are lowest in polar bear, indicating rapid metabolism. Effects of age and sex on residue levels are found for all species where this was measured. Among cetaceans and ringed seal, sexually mature females have lower levels than males due to lactation. Although PCB levels in adult male polar bears are about twice as high as females, there is only a trivial age effect in either sex apart from an initial decrease from birth to sexual maturity (age 0-5). Comparison of levels of S-DDT and PCBs in Arctic beluga and ringed seal with those in beluga in the Gulf of St. Lawrence and ringed seal in the Baltic Sea, indicate that overall contamination of the Arctic marine ecosystem is 10-50 times less than the most highly contaminated areas in the northern hemisphere temperate latitude marine environment. Geographic distribution of residue levels in polar bears indicates a gradual increase from Alaska east to Svalbard, except PCB levels are significantly higher in eastern Greenland and Svalbard. Information on temporal trends is somewhat contradictory.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1991

Influence of biofilms on microbial contamination in dental unit water.

Water from dental units (DU), used for cooling and clearing the field of dental operations, is frequently contaminated by microorganisms. Retrograde spread of oral microbes into DU tubuing, contaminated plumbing systems and endogenous DU contamination have been implicated. This study investigated the contribution of DU tubing to this contamination in 11 randomly selected DU. The times required, under standardized conditions, for DU bacterial levels to decrease in response to the flushing caused by DU operation, or increase in response to stagnation caused by shutting down the DU, were measured. The DU tubing was then removed and similarly manipulated. The results showed similar bacterial levels and populations in the DU and their corresponding tubes. Sixteen control samples taken from the connecting plumbing system at distant locations, after periods of stagnation which result in DU bacterial contamination, were negative. This suggests the plumbing, in our system, is not an important factor. Thus, DU can endogenously contaminate the water passing through them; their tubes have the potential to generate similar magnitudes of bacterial contamination to that determined from intact DU. Scanning electron microscopy of the tube lumens showed a biofilm, characterized by microorganisms embedded in an amorphous matrix in all cases. This biofilm could act as a reservoir to facilitate rapid recontamination. Further analysis of the data indicates there could be other contributing factors.

Bacteria↗

PubMed2004

Effects of blood contamination on the shear bond strengths of conventional and hydrophilic primers.

The purpose of this study was to assess the effect of blood contamination on the shear bond strength and failure site of 2 orthodontic primers (Transbond XT and Transbond MIP; 3M/Unitek, Monrovia, Calif) when used with adhesive-precoated brackets (APC II brackets; 3M/Unitek). One hundred twenty bovine permanent mandibular incisors were randomly divided into 8 groups; each group contained 15 specimens. Each primer-adhesive combination was tested under a different enamel surface condition: dry, blood contamination before priming, blood contamination after priming, or blood contamination before and after priming. Stainless steel APC II brackets were bonded to the teeth. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested for shear bond strength. Noncontaminated enamel surfaces had the highest bond strengths for both conventional and hydrophilic primers; their values were almost the same. Under blood-contaminated conditions, both primers showed significantly lower shear bond strengths. For each type of primer, no significant differences were reported among the blood-contaminated groups. Significant differences in debond locations were found among the groups bonded with the 2 primers under the various enamel surface conditions. Blood contamination of enamel during the bonding procedure of conventional and hydrophilic primers significantly lowers their bond strength values and might produce a bond strength that is not clinically adequate.

Adhesives↗

PubMed2004

Contamination by mercury and cadmium in the cetacean products from Japanese market.

Cetaceans hunted coastally in Japan include several species of odontocete (dolphins, porpoises and beaked whales), and fresh and frozen red meat and blubber, as well as boiled internal organs, such as liver, lung, kidney and small intestine, are still sold for human consumption. Furthermore, red meat and blubber products originating from mysticete minke whales caught in the Antarctic and Northern Pacific are also sold for human consumption. We surveyed mercury and cadmium contamination levels in boiled liver, lung, kidney and red meat products being marketed in Japanese retail outlets. We also analyzed the DNA of these products to obtain information concerning gender and species. Total mercury (T-Hg) and methyl mercury (M-Hg) contamination levels in all the cetacean products were markedly higher in odontocete species than in mysticete species, and slightly higher in females than in males. T-Hg contamination in the organs was seen in the following order: boiled liver>boiled kidney=boiled lung>red meat. In particular, T-Hg concentrations in the boiled liver were high enough to cause acute intoxication even from a single ingestion: the mean +/-SD (range) of T-Hg was 388+/-543 (0.12-1980) microg/wetg. In contrast, although M-Hg contamination in the liver was not markedly higher than that in other organs, M-Hg contamination was in the following order: boiled liver>odontocete red meat>boiled kidney>boiled lung. The contamination levels of T-Hg and M-Hg in odontocete red meat, the most popular whale product, were 8.94+/-13.3 and 5.44+/-5.72 microg/wetg, respectively. These averages exceeded the provisional permitted levels of T-Hg (0.4 microg/wetg) and M-Hg (0.3 microg/wetg) in marine foods set by the Japanese Ministry of Health, Labor and Welfare by 22 and 18 times, respectively, suggesting the possibility of chronic intoxication by T-Hg and M-Hg with frequent consumption of odontocete red meat. Cadmium contamination levels in boiled liver, kidney and lung were 8.59+/-12.0, 10.4+/-8.6 and 1.66+/-1.27 (microg/wetg), respectively.

Animals↗

PubMed2006

Heavy metal contamination of soil and vegetables in suburban areas of Varanasi, India.

Heavy metal contamination of soil resulting from wastewater irrigation is a cause of serious concern due to the potential health impacts of consuming contaminated produce. In this study an assessment is made of the impact of wastewater irrigation on heavy metal contamination of Beta vulgaris (palak); this is a highly nutritious leafy vegetable that is widely cultivated and consumed in urban India, particularly by the poor. A field study was conducted at three major sites that were irrigated by either treated or untreated wastewater in the suburban areas of Varanasi, India according to normal practice. Samples of irrigation water, soil, and the edible portion of the palak (Beta vulgaris L. var All green H1) were collected monthly during the summer and winter seasons and were analyzed for Cd, Cu, Zn, Pb, Cr, Mn, and Ni. Heavy metals in irrigation water were below the internationally recommended (WHO) maximum permissible limits set for agricultural use for all heavy metals except Cd at all the sites. Similarly, the mean heavy metal concentrations in soil were below the Indian standards for all heavy metals, but the maximum value of Cd recorded during January was higher than the standard. However, in the edible portion of B. vulgaris, the Cd concentration was higher than the permissible limits of the Indian standard during summer, whereas Pb and Ni concentrations were higher in both summer and winter seasons. Results of linear regression analysis computed to assess the relationship between individual heavy metal concentration in the vegetable samples and in soil showed that Zn in soil had a positive significant relationship with vegetable contamination during winter. Concentrations of Cd, Cu, and Mn in soil and plant showed significant positive relationships only during summer. Concentration of Cr and Pb during winter season and Zn and Ni during summer season showed significant negative relationships between soil and plant contamination. The study concludes that the use of treated and untreated wastewater for irrigation has increased the contamination of Cd, Pb, and Ni in edible portion of vegetables causing potential health risk in the long term from this practice. The study also points to the fact that adherence to standards for heavy metal contamination of soil and irrigation water does not ensure safe food.

Agriculture↗

PubMed2005

Soil As contamination and its risk assessment in areas near the industrial districts of Chenzhou City, Southern China.

In order to assess soil As contamination and potential risk for human, soil, paddy rice, vegetable and human hair samples from the areas near the industrial districts in Chenzhou, southern China were sampled and analyzed. The results showed that the anthropogenic industrial activities have caused in local agricultural soils to be contaminated with As in a range of 11.0-1217 mg/kg. The GIS-based map shows that soil contamination with As occurred on a large scale, which probably accounted for up to 30% of the total area investigated. Soil As concentration abruptly decreased with an increase in the distance from the polluting source. High As concentrations were found in the rice grain that ranged from 0.5 to 7.5 mg/kg, most of which exceed the maximal permissible limit of 1.0 mg/kg dry matter. Arsenic accumulated in significantly different levels between leafy vegetables and non-leafy vegetables. Non-leafy vegetables should be recommended in As-contaminated soils, as their edible parts were found in relatively low As level. Arsenic concentrations in 95% of the total human hair samples in the contaminated districts were above the critical value, 1.0 mg/kg, set by the World Health Organization. Arsenic could be enriched in human hair to very high levels without being affected by As containing water. The results revealed that the soils and plants grown on them are major contributors to elevate hair As in the industrial population. Therefore, the potential impact on human health of ingestion/inhalation of soil As around the industrial districts seems to be rather serious. Hence proper treatments for As contaminated soils are urgently needed to reduce the contamination.

Arsenic↗

PubMed2006

Dietary composition and contaminants in north Greenland, in the 1970s and 2004.

OBJECTIVES: The fatty acid composition and other nutrients in traditional Inuit food appear to provide some protection against diseases of affluent industrialized societies, such as cardiovascular diseases and type 2 diabetes. A transition towards increased amounts of imported food might increase the occurrence of these diseases among Inuit. However, since the 1970s it has become evident that the marine-based Inuit diet also contains high levels of potentially toxic lipophilic organic pollutants and heavy metals. Since these two opposing effects on health appear to be inseparable, the phenomenon has become known as "The Arctic Dilemma". However, both the fatty acid composition and the contaminant levels vary in Greenlandic food items. Thus, in theory, it is possible to compose a diet where the benefits outweigh the risks. Our objective was to compare traditional and modern meals in Greenland regarding dietary composition, content of n-3 fatty acids and contaminants. STUDY DESIGN: The present study was part of the Arctic Monitoring and Assessment Programme, AMAP, comparing the results of dietary composition and nutrients in 177 traditional meals collected in Uummannaq municipality, north Greenland in 1976 with 90 meals sampled in Uummannaq town in 2004 under similar conditions. Eleven pesticides, 14 PCB congeners, heavy metals, selenium, and fatty acids were analysed in meals and blood samples from the participants. Contaminant levels were compared between 1976 and 2004 after adjustment for n-3 fatty acids, indicating local food content. RESULTS: Between the traditional meals collected 30 years ago and the meals from 2004, dramatic and significant changes have occurred in the dietary composition. The percentage of local food has decreased, and with it the intake of n-3 fatty acids. Calculated as daily intake, all but three contaminants had decreased significantly. However, this could be explained by the lower intake of local food. After adjustment for n-3 fatty acid content in the food, significant declines of concentration in the local food were evident only for PCBs and lead, whereas for mercury, DDTs, and chlordanes the levels were unchanged, and for hexachlorobenzene, mirex, and toxaphenes, the levels had increased significantly. CONCLUSION: The consumption of locally produced food has decreased in Greenland during the last 30 years and this has led to a reduction in the daily intake of contaminants. However, the concentrations of contaminants in local food items have not decreased, except for PCB and Lead. Therefore, we recommend that the consumption of local products is not increased beyond the present level, until the level of contaminants is reduced to a safer level.

Diet↗

PubMed2002

Contamination of single-use biopsy forceps: a prospective in vitro analysis.

BACKGROUND: It has been suggested that single-use biopsy forceps prevent interpatient transmission of infection during endoscopy. Passage of sterile forceps through the accessory channel of the endoscope may lead to contamination, however, if the endoscope has been inadequately processed. The potential for contamination of single-use biopsy forceps at various stages of endoscope reprocessing was prospectively evaluated. METHODS: A total of 50 disposable biopsy forceps were passed through the accessory channels of 10 colonoscopes at the following stages of reprocessing: (1) before use in patients to establish a baseline of high-level disinfection, (2) directly after colonoscopy to confirm contamination with use, (3) after manual cleaning and flushing of the accessory channel to support the claim that manual cleaning significantly decreases bioburden, (4) after manual cleaning and a 2-minute soak in 2% glutaraldehyde to assess for contamination after an inadequate cleaning time, and (5) after manual cleaning and a 20-minute soak in 2% glutaraldehyde. The forceps were then sealed in sterile plastic bags after adding 20 mL of thioglycollate broth medium. The suspension was passed through a 0.2-micron vacuum filter and the filters were cultured. All cultures were incubated more than 48 hours. RESULTS: Biopsy forceps underwent a total of 50 aerobic and 50 anaerobic cultures. Colony-forming units too numerous to count of GI flora, including Escherichia coli, Klebsiella, Pseudomonas, and Clostridium species, grew on 19 of 20 culture plates from biopsy forceps passed through colonoscopes immediately after use. One plate in this group grew 3 colony-forming units of E coli. Persistence of GI flora was noted on 5 of 20 plates after manual cleaning of the colonoscopes. No GI flora were found on forceps after the colonoscopes after soaking in gluteraldehyde for 2 and 20 minutes. Environmental contaminants including diptheroids, Staphylococcus, and Streptococcus species grew on 16 culture plates. CONCLUSIONS: (1) Single-use biopsy forceps are highly susceptible to contamination during passage through the accessory channels of improperly cleaned endoscopes. (2) Disinfection of the colonoscopes in this study prevented contamination of the forceps at baseline and after reprocessing. (3) Proper endoscope reprocessing may be the most important factor in preventing biopsy forceps-related interpatient infection.

Bacteria↗

PubMed2001

Use of PFGE typing for tracing contamination with Listeria monocytogenes in three cold-smoked salmon processing plants.

The sites of Listeria monocytogenes contamination in three cold-smoked salmon (Salmo salar) processing plants were detected by sampling salmon and the plant's environment and equipment at different production stages. Of the 141 samples collected from three processing plants, 59 (42%) were contaminated with L. monocytogenes. The rates of contamination varied as to the plant and the sample source. L. monocytogenes isolates from 17 various contaminated seafood products (fresh, frozen and smoked fishes, cooked mussels) were also studied. A total of 155 isolates from the three plants and the various seafoods were characterized by genomic macrorestriction using ApaI and SmaI with pulsed-field gel electrophoresis (PFGE) and 82 isolates were serotyped. Macrorestriction yielded 20 pulsotypes and serotyping yielded four serovars: 1/2a, 1/2b, 1/2c, 4b (or e), with 77 (93%) belonging to serovar 1/2a. One clone of L. monocvtogenes predominated and persisted in plant I and was the only pulsotype detected in the final product although it was not isolated from raw salmon. No L. monocytogenes was detected in the smoked skinned salmon processed in plant II, even though 87% of the raw salmon was contaminated. All the smoked salmon samples collected in plant III were contaminated with a unique clone of L. monocytogenes, which may have occurred during slicing. In the three plants, the contamination of final products did not seem to originate from the L. monocytogenes present on raw salmon, but from the processing environment.

Animals↗

PubMed2002

Current contamination by 137Cs and 90Sr of the inhabited part of the Techa river basin in the Urals.

Previous discharges of radioactivity from the Mayak Production Association plant in the Urals have resulted in considerable radionuclide contamination of the Techa River, and consequent high radiation doses during the late 1940s and 1950s to residents of villages along the Techa river. The most contaminated villages close to the site were evacuated in the period 1954-1962. The objective of this recent study was to conduct a preliminary assessment of the current radioactive contamination of soil, vegetation and foodstuffs in the two remaining villages closest to the Mayak site, Muslyumovo and Brodokalmak. The highest contamination levels in soil were found in the floodplain at 5.5 MBq m(-2) for 137Cs and 1.0 MBq m(-2) for 90Sr. Radionuclide contamination in soil of the villages was much lower, but exceeded that expected from global fallout. Data from 1207 measurements of 137Cs in milk and 1180 for 90Sr in milk for the period 1992-1999 were collated. There was no change with time in the 90Sr or 137Cs activity concentration in milk over the measured period. There were significantly higher 137Cs activity concentrations in milk sampled during the housed winter period in Muslyumovo compared with the grazing summer period, but compared to that for Brodokalmak or for either settlement for 90Sr. The highest measured activity concentrations in food products of 137Cs and 90Sr were found in river fish, waterfowl, poultry and milk. The measured activity concentrations of 137Cs and 90Sr in some animal products were higher than that expected from soil and vegetation from fields and pasture in the villages (not including the floodplain) confirming that the highly contaminated floodplains are contributing to contamination of some animal products.

Agriculture↗

PubMedDate not supplied

[Detection of external contamination of methotrexate vials in an Argentine hospital].

OBJECTIVE: To quantify external contamination of methotrexate vials and alert about occupational health hazards. METHOD: All 50 mg and 500 mg methotrexate vials were opened and cleaned with an alcohol wet white wipe in February 2005. The vials were divided in two groups according to visual external contamination or not. The air tightness of the vials was stated. RESULTS: 9.33% methotrexate vials were contaminated under visual inspection. Two of five manufacturers presented contaminated vials. The proportion of contaminated vials in the two former manufacturers was 18.8 and 21.43%. CONCLUSIONS: External contamination would be due to manufacture processes. Cutaneous absorption is very important because of the contamination founded. It s strongly recommended that all personal involved in cytotoxic handling take protection measures.

Antineoplastic Agents↗

PubMed2002

Uptake of trace elements and PAHs by fruit and vegetables from contaminated soils.

The aims of this study were to investigate the uptake of seven trace elements and five PAHs in crop plants in order to establish advice regarding consumption of fruit and vegetables grown in soils contaminated by trace elements and PAHs. In a field experiment, vegetables were grown in two contaminated soils and in a reference soil, whereas fruits were collected from uncontaminated and contaminated private gardens. The results showed elevated levels of several trace elements and PAHs in the vegetables from contaminated soil. Bioconcentration factors (BCF values), based on dry weight, were below 1, except for those of Cd in lettuce and carrot with peel from uncontaminated soil. In most cases, BCF values were decreasing with increasing concentrations in soil. From the heavily contaminated soil, BCF values for Pb in lettuce, potato, and carrot with peel were 0.001, 0.002, and 0.05, respectively, and those for benzo[a]pyrene were 0.004, 0.002, and 0.002, respectively. For most metals in most vegetables, linear regression showed good correlation between soil and crop concentrations. For PAHs, such good correlation was generally not found. The contents of contaminants in fruits were generally low and no correlation with the level of contamination in the soils was found.

Biological Availability↗

PubMed2006

Maize (Zea mays L.) genetic factors for preventing fumonisin contamination.

Fusarium moniliforme and Fusarium proliferatum are the most frequently isolated fungi from maize (Zea mays L.) in Spain. Both Fusarium species produce toxins potentially dangerous for animals and humans, the fumonisins being the most significant of those toxins. White maize is preferred for human consumption, and extra care should be taken to avoid kernel mycotoxin contamination. The objectives of this study were to identify and quantify kernel infection by Fusarium spp. and contamination by fumonisin on white maize hybrids, to search for white maize sources of resistance to infection by Fusarium spp. and mycotoxin contamination, and to preliminarily study the genetics involved in such resistances. Ten F(1) single crosses derived from a diallel mating design among five white maize inbreds were evaluated in a randomized complete block design with three replications in 2002 at two locations. Fusarium verticilloides and F. proliferatum were detected on kernels of white maize hybrids cultivated in northwestern Spain. No differences in fungal infection were found among maize genotypes, but differences in fumonisin contamination were significant and could be related, in part, to differences in husk tightness. Among the genotypes studied, general combining ability (GCA) effects were the most important for resistance to fumonisin contamination. Inbreds EP10 and EC22 showed the most favorable GCA effects for husk tightness and fumonisin content, and the cross between them, EP10 x EC22, had the most favorable specific combining ability (SCA) effect for husk tightness. Inbreds EP10 and EC22 showed favorable GCA effects for fumonisin contamination and husk tightness, and the cross EP10 x EC22 was the only one with an average fumonisin level below 1 mug/g. Although this should be confirmed with more extensive studies, white maize inbreds developed from white maize landraces could be sources of resistance to fumonisin contamination.

Breeding↗

PubMed1998

Contamination of embryo transfer catheter and treatment outcome in in vitro fertilization.

PURPOSE: The effect of embryo transfer (ET) catheter contamination with mucus and/or blood on treatment outcome in an in vitro fertilization (IVF) program was evaluated. METHODS: One thousand four ET procedures in 877 patients having conventional IVF in the long (1189 cycle) and short (15 cycles) protocol were analyzed to determine the impact of catheter contamination on the incidence of retained embryos and the clinical pregnancy rate. RESULTS: Catheter contamination with mucus and/or blood is a feature of difficult ET. Embryos were significantly more likely to be retained when the transfer catheter was contaminated with mucus (17.8 versus 3.3%) or blood (12 versus 3.3%). When the catheter was contaminated and an embryo(s) was retained and immediately retransferred, the pregnancy rate was not compromised. The pregnancy rate was significantly reduced when the ET catheter was contaminated with blood (15.5 versus 27.1%; P = 0.002), but no embryo was retained in the catheter set. CONCLUSIONS: Catheter contamination compromises the treatment outcome in IVF only when there is no associated retained embryo(s). As increased vigilance in searching for extruded embryos may not be practical, we suggest that cervical mucus should be routinely aspirated and ET performed as atraumatically as possible.

Adult↗

PubMed2005

A study of visual and blood contamination on reprocessed endodontic files from general dental practice.

OBJECTIVE: This study examined methods used for reprocessing endodontic instruments in general dental practice and determined the degree of residual visual contamination and blood contamination on 250 reprocessed files collected from 25 general dental practices. MATERIALS AND METHODS: A questionnaire was administered to 25 general dental practitioners to obtain information on the re-processing of used endodontic files. Ten files which had been used and reprocessed were also collected from each practice. These were examined visually under a dissecting light microscope for residual contamination and then tested for blood deposits using the Kastle-Meyer test. RESULTS: Nineteen of the 25 practices used stainless steel hand files. No practitioners used endodontic files as single use devices. Ninety-two per cent of the practitioners discarded and replaced files when they were bent or damaged. Several decontamination methods were reported. The two combinations employed most frequently were manual cleaning and autoclaving or manual cleaning, followed by ultrasonic cleaning and autoclaving. Of the 250 files, 75% showed some degree of visual contamination and seven percent tested positive for residual blood. Blood contaminated files were significantly more heavily contaminated when examined visually. Large variations were found in residual contamination of files collected from practices using the same methods of decontamination. CONCLUSIONS: While all practitioners re-used endodontic files, the variations in decontamination methods reported indicate a lack of clarity on best practice. This study demonstrates that endodontic files are not reliably decontaminated by methods currently employed in dental practice.

Blood↗

PubMed2003

Monitoring of apheresis platelet bacterial contamination with an automated liquid culture system: a university experience.

BACKGROUND: With 4 million platelet units transfused per year in the United States and with the current estimate of bacteria contamination rate in PLT units, it would be expected that 2000 to 4000 bacterially contaminated units are transfused and associated with 333 to 1000 cases of clinical sepsis. STUDY DESIGN AND METHODS: Apheresis platelets were sampled on Day 2 of storage (collection day=Day 0) and issue (or following outdate, Days 6-8) using a sterile connection device (SCD) to attach a sampling bag. Using aseptic technique and a laminar flow hood, bottles were inoculated and placed onto an automated liquid culture system (BacT/ALERT 3D Microbial Detection System) for 7 days. RESULTS: A total of 2397 apheresis PLT units were sampled. A triple apheresis collection was reactive within 14 hours of the Day 2 sampling (aerobic bottles) and the bags were removed from inventory. Staphylococcus epidermidis was identified in all three contaminated bags. Two double-apheresis collections were found to be contaminated with Proprionibacterium sp. after 6 days of incubation but had been transfused to four patients without discernible clinical sequelae. There was one false-positive aerobic bottle and one false-positive anaerobic result due to inadvertent contamination of a bottle. Thus, the overall true-positive rate was 7 of 2397 apheresis units (0.29%) with a true-positive rate for aerobic organisms of 0.13% and an anaerobic true-positive rate of 0.17%. The false-positive rate was 2 out of 4794 samplings (0.04%) or 2 out of 9588 bottles (0.02%). CONCLUSION: This preliminary data suggests that the use of a SCD, aseptic technique, and a laminar flow hood is associated with a low rate of contamination. In no case did an issue (or outdate) detect contamination that was not detected by the Day 2 culture. Additional surveillance is necessary before we can conclude that a Day 2 sterile culture is truly predictive of an issue (or outdate) sterile culture. Bacterial culture surveillance of PLTs would be expected to save lives and may facilitate an extension in PLT storage.

Adult↗