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PubMed1988

Predictors of intraoperative bacterial contamination and postoperative infection in elective colorectal surgery.

This prospective study of 238 patients undergoing colorectal operations attempted to identify the risk factors for intraoperative bacterial contamination and postoperative infection. The degree of contamination was assessed by the recovery of Enterobacteriaceae spp. or Staphylococcus aureus in peritoneal irrigation fluid using dip-slides. Uni- and multivariate analyses comprised 17 parameters. Intraoperative contamination was strongly associated with postoperative infection (P less than 0.001). Abdominal drains were correlated with contamination (P = 0.019), but not with infection. Decompressive colostomy was over-represented in patients with contamination (P less than 0.001) but contributed to infection independent of its association with contamination (P less than 0.05), as did advanced age (P less than 0.05).

Adolescent↗

PubMed1992

Test models for hygienic handrub and hygienic handwash: the effects of two different contamination and sampling techniques.

Two methods for artificial contamination of hands and two sampling techniques to recover the test organisms were compared for their effects on the results of two post-contamination hand treatments: a handrub with two portions of 3 ml of 2-propanol 60% v/v for 1 min, and a handwash with liquid soap 20% w/v for 1 min followed by a 15 s rinse. The two contamination methods involved a short immersion of the hands (up to the middle of the mid-hand) in a suspension of the test organism followed by either air-drying (3 min) or drying by rubbing the hands' vigorously against each other (3 min) in a standardized way. The two sampling techniques consisted of rubbing the fingertips in either 10 ml trypticase soy broth (TSB) against the bottom of a Petri dish; or 100 ml TSB against glass beads contained in a bowl. Sixteen volunteers were randomly allotted to four blocks of four. They carried out the four possible combinations of two treatments and two contamination methods in a series of four tests arranged in a Latin-square design. In addition, the two sampling techniques were compared with each other concurrently by sampling of the right and left hand each with a different one of the two techniques. The alcoholic handrub reduced the release of test organisms significantly (2P less than 0.005) more effectively, by 1.1-1.3 x log10, than did the handwash with liquid soap, regardless of the contamination or sampling method. Whereas the two recovery techniques yielded virtually identical results in corresponding situations, the method of artificial contamination affected the mean reduction factors, strongly.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Propanol↗

PubMed1992

Handwashing and disinfection of heavily contaminated hands--effective or ineffective?

Hands are among the principal vehicles for transfer of nosocomial pathogens in hospitals. Often, outbreaks of infection are thought to be caused by a lack of compliance with handwashing guidelines, rather than due to the inadequacy of the handwashing agents used. In this study the effectiveness of proper handwashing and the use of three different hand disinfectants: ethanol 70% (E), isopropanol 40% (I) and alcoholic chlorhexidine (70%) (AC) was compared using three volunteers whose fingertips were heavily contaminated with a succession of bacteria including: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli and Enterobacter cloacae. After each contamination, thorough handwashing and application of one disinfectant on the hands were performed three times. Fingerprint-samples were taken before and 1 min after application of the disinfectants. Thorough handwashing with an ordinary liquid soap ('Sterisol') did not reduce the confluent growth of bacteria on fingertips for any of the species used (197 examinations). Only AC had a significant effect on fingers heavily contaminated with S. aureus (126 examinations; AC compared with E and I; P less than 0.0002 and P less than 0.0002 respectively), but did not completely eradicate the bacteria. After contamination with Ent. cloacae (118 examinations), none of the three agents were particularly effective, but E and AC seemed to be somewhat more effective than I (P less than 0.0002 and P less than 0.01 respectively). When successive contamination was performed using all bacterial species, AC was the most effective decontaminant. However, Ent. cloacae was still present on the fingertips after 15 repeated courses of handwashing and applications of disinfectants. Bathing of hands in AC for 20s completely eradicated all bacteria from the hands. The study demonstrates that, when heavily contaminated, an ordinary handwashing followed by disinfectants is not enough to eradicate potentially pathogenic bacteria from the hands.

1-Propanol↗

PubMed1994

Comparative effectiveness of hand-cleansing agents for removing methicillin-resistant Staphylococcus aureus from experimentally contaminated fingertips.

BACKGROUND: Five subjects participated in a study of optimal conditions for removing methicillin-resistant Staphylococcus aureus from contaminated fingertips. METHODS: Fingertips were contaminated experimentally and cleaned by various methods. Bacterial removal was measured as percentage and is given as mean +/- standard error of the mean. RESULTS: Rinsing the fingertips with tap water for 20 seconds and drying them with paper towels removed 95.2% +/- 1.6% of the contamination. Application of hand-cleansing agents to fingertips for 20 seconds, followed by a 20-second tap-water rinse and towel drying, removed bacteria as follows: povidone-iodine detergent, 99.2% +/- 0.4%; chlorhexidine detergent, 97.2% +/- 0.8%; and liquid soap, 96.1% +/- 1.1%. In a modification of the method, 80% ethyl alcohol applied to the fingertips for 20 seconds, followed by air drying for 40 seconds, removed 99.1% +/- 0.8% of the bacteria. Statistical analyses indicated that povidone-iodine and 80% ethyl alcohol were more effective than the other agents. CONCLUSIONS: Rinsing contaminated fingertips with tap water and towel drying them is sufficient to reduce contamination with methicillin-resistant S. aureus by 95%. Washing with povidone-iodine or 80% ethyl alcohol further reduces contamination by an additional 99%.

Adult↗

PubMed1990

Decanting--a source of contamination of enteral feeds?

The techniques of opening and decanting ready-to-use enteral feeds packaged in bottles (crown-cap and screw-cap), cans and tetrapaks were evaluated as potential routes for the contamination of these feeds. It was found that the outsides of the feed containers, bottle openers, scissors and the experimenters' hands all acted as sources of contamination during the transfer of feeds to the nutrient container. The main source of contamination appeared to be the experimenters' hands with counts up to 10(2) cfu ml(-1) being recorded for feeds that had been decanted from screw-cap bottles, cans and tetrapaks by experimenters with either unprotected bare hands or hands experimentally contaminated with K. aerogenes. Levels of contamination and the number of samples contaminated after opening and decanting were consistently higher for cans and tetrapaks than for crown-cap or screw-cap bottles. Disinfection of feed containers followed by the use of sterile gloves and/or disinfected openers yielded bacteria-free feed from all the types of feed container studied.

Journal Article↗

PubMed1987

Oil contamination of raptors migrating along the Red Sea.

There are few accounts of oil contamination of raptors, and it has not been considered a threat for them. However, we and our colleagues found oil-based asphalt on 55 individuals of 9 species out of 1052 raptors (5.2%) captured and examined in the spring of 1985 and 1986 during our raptor migration study at Elat, Israel. Some were extensively contaminated and probably succumbed to the effects of ingested asphalt. The birds most likely picked up the contamination while drinking water from pools with surface oil. Examples of the contamination will be described. Over 1.2 million raptors were counted passing Elat during the spring of 1985. If 5% of these were contaminated, that would be over 60,000 birds, and this does not consider the raptors that migrate along the Red Sea and do not pass near Elat, nor those that pass Elat unseen by the counters. Thus asphalt contamination could be a major problem for raptors migrating along the Red Sea.

Journal Article↗

PubMed1988

Influence of contaminated particles on the bioaccumulation of hydrophobic organic micropollutants in fish.

The influence of contaminated particles on the bioconcentration of hydrophobic chemicals by fish is dependent on the hydrophobicity of the chemicals. This has been shown for polychlorinated benzenes and biphenyls (ranging over three orders of magnitude in octan-1-ol/water partition coefficient) which are sorbed on very low organic carbon content particles. For chemicals with low to moderate hydrophobicity, the amount of the chemical which is sorbed, relative to the amount which is dissolved, determines the influence that contaminated particles have on the uptake of the chemicals by fish. In this present experiment, for lower chlorinated benzenes and biphenyls, the amount dissolved in water are high compared with the amounts which are present in the sorbed state, and the influence of contaminated particles on their uptake by fish is negligible. For more hydrophobic chemicals, which have lower aqueous solubilities, such as penta and hexachlorobenzene, and tri and tetrachlorobiphenyls, contaminated particles can have a much greater influence on the uptake by fish. If the number of contaminated particles is sufficiently high, the low aqueous solubilities, in combination with relatively high rates of desorption or dissolution, enable the particles to act as a source of the hydrophobic chemicals. For extremely hydrophobic chemicals, the rates of dissolution or desorption determine the rates of uptake of the chemical by the fish. Hence, during relatively short periods of exposure, there is no influence of contaminated particles on the bioaccumulation.

Journal Article↗

PubMed1991

Contaminant trends in soils and crops.

The evidence for long-term changes in the contaminant content of soils and crops is reviewed. Heavy metals, acidification and trace organic contaminants are each considered separately, with the emphasis placed on changes brought about by inputs from long-term atmospheric deposition. It is argued that effectively all soils in industrialised countries have become contaminated with selected trace substances (notably Pb, Cd, polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins and -furans) above their true (historical) background level by aerial inputs. In the case of Pb, for example, cumulative deposition inputs over several centuries have probably roughly doubled the Pb burden of contemporary UK surface soils. Despite this, there is little evidence for a concomitant rise in the contaminant content of UK crops through the twentieth century. In fact, the burden of many contaminants in vegetation may well be somewhat lower than in earlier decades of this century because (1) crop composition is strongly influenced by direct deposition onto the above-ground portion of the plant, (2) root uptake and translocation of soil-borne heavy metals and recalcitrant organic contaminants are inefficient processes, and (3) UK air quality has generally improved over the last 10-20 years. Acidification of soils is of considerable regional significance. The evidence for changes in soil pH over this century is reviewed, and it is concluded that atmospheric inputs have enhanced the rate of soil acidification over large areas of Scandinavia and elsewhere.

Journal Article↗

PubMed1988

The psychological dimensions of health care for patients exposed to radiation and the other invisible environmental contaminants.

Invisible environmental contaminants are those contaminants that possess environmental and/or medical invisibility. Recent studies indicate: (1) that these contaminants can and do have traumatic psychological effects on those individuals who have been exposed to them and (2) that there is a remarkable uniformity to these traumatic affects as they have been found in the various invisible exposures that have been studied to date. The common denominators in all of these situations is the invisibility of the involved contaminants. The adverse psychological effects of the invisible contaminants are as follows: (1) experienced uncertainty, (2) adaptational dilemmas, (3) hypervigilance, (4) nonempirical belief systems about the exposure, and (5) traumatic neuroses. This paper will: (1) review the data that documents the occurrence of psychological effects of the invisible environmental contaminants, (2) present an adaptational model that explains the manner in which these psychological trauma develop, and (3) examine the clinical and public policy implications of these findings.

Environmental Pollutants↗

PubMed1985

Variables determining the amount of microbial contamination on cadaveric allograft skin used as a biological wound dressing.

The increased availability and use of cadaveric allograft skin as a temporary burn wound dressing has emphasized the need for a complete understanding of the parameters affecting the contamination level of this material. We undertook a prospective evaluation of the allograft skin obtained from 300 cadaveric donors over 5 years. We evaluated the contribution to skin contamination of eight parameters: sex, age, race, cause of death, elapsed time postmortem before skin removal, total refrigerated storage time of the skin prior to cryopreservation, donor body area from which the skin was removed, and choice of surgical operators or teams. The only parameters significantly related to skin contamination level were the choice of surgical operator or team which prepared the body and removed the skin (P = 0.0001) and the acceptance of skin from donors when the cause of death was unknown but presumed to be from natural causes (PNC) such as myocardial infarction or cerebral vascular accident (P = 0.006). In the case of the PNC deaths, there was only a small 3.4 per cent increase in bacterial contamination and no increase in fungi or yeast, while some surgical operators were associated with five-fold more bacterial contamination and nearly 13-fold more fungal contamination than other surgical operators. We conclude that the performance of surgical operators appears to be the major determinant of the microbiological cleanliness of skin from cadaveric allograft donors.

Age Factors↗

PubMed1985

The role of sampling in the detection of microbial contamination on cadaveric allograft skin used as a biological wound dressing.

The availability of cryopreservation and low temperature storage techniques for cadaveric allograft skin allows it to be preserved while microbial assessments are made before its use as a temporary biological dressing on burn wounds. In a 300-donor, 5-year prospective study, we tested ten skin samples from defined areas on each donor for microbiological contamination. Although the skin from 52.3 per cent of the donors possessed some detectable residual microbial contamination after surgical body preparation and skin removal, such contamination was limited to an average of 1.4 areas per body, leaving 86 per cent of all skin obtained free from detectable contamination and suitable for use as biological wound dressings. The number of skin samples tested per donor body determined the accuracy of detection of the presence of contamination. Testing one skin sample per donor body yielded a correct skin assessment 92 per cent of the time, while testing five skin samples increased the accuracy to 96 per cent, and testing ten skin samples yielded a 99.9 per cent accuracy in detection of skin contamination. Thus, it is within the ability of a skin bank to set the limits of microbiological risk to patients receiving processed cadaveric allograft skin.

Bacteria↗

PubMed1986

Enzymatic activity in crude oil contaminated rats.

The activity of enzymes found in the plasma, malate dehydrogenase (MDH) and lactate dehydrogenase (LDH), and enzymes from erythrocytes, glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase, was studied in rats contaminated by crude oil. Crude oil (tube fed) contamination caused a significant increase in MDH and LDH activity 96 hr after contamination while a decrease in activity was noted in 6-6-PDH and catalase. An additional contamination (1 week after the first contamination), measured 96 hr after contamination, caused a relative decrease in MDH and LDH activity while there was a contrasting relative increase in G-6-PDH and catalase activity. After a recovery period of 3 weeks the only significant change was an increase in catalase activity.

Animals↗

PubMed2004

The challenge of determining aqueous contamination rate in anterior segment intraocular surgery.

PURPOSE: To determine aqueous contamination rate in anterior segment intraocular surgery using two different techniques of obtaining aqueous fluid and to assess whether a 3-day application of topical 0.3% ofloxacin reduces this contamination rate compared with a 1-hour application. DESIGN: Randomized clinical trial. METHODS: One hundred and thirty-three eyes of 130 patients undergoing anterior segment intraocular surgery were randomized to either control (64 eyes received topical ofloxacin 1 hour before surgery) or study groups (69 eyes received topical ofloxacin four times a day for 3 days before surgery in addition to 1 hour preoperatively). Eyes in both groups received a periorbital iodine scrub and two drops of topical 5% iodine. Aqueous fluid was obtained at the beginning and conclusion of surgery using a cannula passed through a paracentesis or a needle passed through clear cornea. The aqueous, cannula, and needles were inoculated in blood culture media broth and bacterial growth was identified. RESULTS: Overall, eight of 89 aqueous samples (9%) obtained using a cannula at the beginning of surgery were culture-positive. Similarly, six of 41 aqueous samples (15%) obtained through a needle through clear cornea at the beginning of surgery showed contamination. At the conclusion of surgery, nine of 112 samples (8%) showed positive cultures. There was no difference in the aqueous contamination rates between the control and study groups. CONCLUSIONS: Despite the use of a needle to obtain aqueous fluid at the beginning of surgery before creating a paracentesis, the aqueous contamination rate remained higher than that found at the conclusion of surgery. A 3-day application of topical ofloxacin before surgery did not reduce the anterior chamber aqueous contamination rate relative to a 1-hour application.

Anterior Eye Segment↗

PubMed2004

Effect of blood contamination on shear bond strength of brackets bonded with conventional and self-etching primers.

This study assessed the effect of blood contamination on the shear bond strength and bond failure site of 2 different orthodontic primers (Transbond XT and Transbond Plus Self-Etching Primer, both from 3M Unitek, Monrovia, Calif) used with adhesive-precoated brackets. Four different enamel surface conditions were tested: (1) dry, (2) blood contamination before priming, (3) blood contamination after priming, and (4) blood contamination before and after priming. Noncontaminated enamel surfaces had the highest bond strengths for both conventional and self-etching primers, which produced almost the same strength values. Under blood-contaminated conditions, both primers showed significantly reduced shear bond strengths. For the conventional primer, no significant differences were reported among the blood-contaminated groups, whereas when the self-etching primer was used, condition 4 reduced significantly the bond strength values. Significant differences in debond locations were found among the groups bonded with the 2 primers under the various enamel surface conditions.

Acid Etching, Dental↗

PubMed2004

Daphnia need to be gut-cleared too: the effect of exposure to and ingestion of metal-contaminated sediment on the gut-clearance patterns of D. magna.

The presence of sediment particles in the gut indicated that Daphnia magna used in whole-sediment bioassays ingest sediment. If gut contents are not removed prior to whole-body tissue-burden analysis, then the bioavailability of any sediment-associated contaminants (e.g. metals) can be overestimated. Gut clearing patterns were determined for D. magna after exposure to both clean and metal-contaminated (Cu and Zn) field-collected sediments. D. magna exposed to reference sediment had fuller guts than those exposed to metal-contaminated sediment (95% versus 60% full). Neither reference- nor metal-exposed D. magna could clear their gut completely of sediment particles when held in clean water for 24 h. When Daphnia were transferred to clean water after exposure to metal-contaminated sediment, there was no significant decrease in gut-fullness (P>0.05) even after 48 h of purging. By comparison, animals transferred to water containing 5 x 10(5) cells of algae (Pseudokircheriella subcapita) after exposure to contaminated sediment showed a significant drop in gut fullness from 56% immediately after exposure to 17% after 4 h of gut-clearance. Although gut fullness did not change significantly beyond 2 h of purging, data were much less variable after 8 h of gut-clearance than after 2 h or 4 h. The depuration of Cu was well described with a two-compartment first-order kinetic model (r2=0.78, P<0.0001) indicating that D. magna exposed to metal-contaminated sediment have one pool of Cu that is quickly depurated (0.2 h(-1)), and one that has been incorporated into the tissues (<<0.00001 h(-1)). Assuming tissue background of 48 microg/g, an exposed animal which has not been depurated or which has been purged with water alone would yield whole-body tissue Cu concentrations that are 5.6- and 4-fold higher, respectively, than that purged with algae + water (8 h). We recommend that D. magna used to estimate metal bioavailability from sediment be gut-cleared in the presence of algae for 8 h prior to determination of whole-body metal concentrations.

Animals↗

PubMed2005

Impact of cadmium contamination and oxygenation levels on biochemical responses in the Asiatic clam Corbicula fluminea.

The aim of this work was to evaluate the potential utility of several biochemical parameters as indicators of the toxic effects of cadmium in the freshwater clam Corbicula fluminea under two levels of oxygenation (normoxia 21 kPa and hypoxia 4 kPa). These variations in oxygenation are representative of the natural environments of bivalves living at the bottom of the water column, where hypoxic episodes may occur regularly. Cadmium accumulation, metallothionein synthesis, MXR protein induction, lipoperoxidation and antioxidant enzyme activities (catalase, glutathione reductase and total and selenium-dependent glutathione peroxidases) were assessed in the gills of C. fluminea in four experimental conditions: normoxia, hypoxia, normoxia with cadmium and hypoxia with cadmium ([Cd]=30 microg l(-1)) over a 14-day period. Behavioural reactions were also followed for the duration of the experiment by monitoring clam activity and valve movements. This study is a first report on biochemical responses under cadmium contamination and hypoxia and will enable us to determine better biomarkers for C. fluminea as they were measured simultaneously. In metal-exposed animals, we found an increasing accumulation of cadmium in the gills with time, and this was more severe in hypoxic conditions. Metallothionein synthesis occurred in contaminated clams and was precocious in hypoxic conditions. MXR protein induction appeared promising due to its quick and significant response to metal with a strong impact from hypoxic contamination. On the other hand, in our experimental conditions, antioxidant parameters did not show decisive responses to contamination and hypoxia, except glutathione peroxidases which decreased systematically with time in a cadmium-independent manner. Lipid peroxidation, expressed as malondialdehyde content, was not stimulated by normoxic contamination, as has been shown in other studies, but was stimulated under hypoxic cadmium contamination. Our study confirms the importance of a multi-biomarker approach in environmental studies as some are not appropriate to all organisms.

Analysis of Variance↗

PubMed2005

Removal of polycyclic aromatic hydrocarbons from manufactured gas plant-contaminated soils using sunflower oil: laboratory column experiments.

Laboratory column experiments were performed to remove PAHs (polycyclic aromatic hydrocarbons) from two contaminated soils using sunflower oil. Two liters of sunflower oil was added to the top of the columns (33 cm x 21 cm) packed with 1 kg of PAH-contaminated soil. The sunflower oil was applied sequentially in two different ways, i.e. five additions of 400 ml or two additions of 1l. The influence of PAH concentration and the volume of sunflower oil on PAH removal were examined. A soil respiration experiment was carried out and organic carbon contents of the soils were measured to determine degradability of remaining sunflower oil in the soils. Results showed that the sunflower oil was effective in removing PAHs from the two soils, more PAHs were removed by adding sunflower oil in two steps than in five steps, probably because of the slower flow rate in the former method. More than 90% of total PAHs was removed from a heavily contaminated soil (with a total 13 PAH concentration of 4721 mg kg(-1)) using 4 l of sunflower oil. A similar removal efficiency was obtained for another contaminated soil (with a total 13 PAH concentration of 724 mg kg(-1)), while only 2l was needed to give a similar efficiency. Approximately 4-5% of the sunflower oil remained in the soils. Soil respiration curves showed that remaining sunflower oil was degraded by allowing air exchange and supplying with nutrients. Organic carbon content of the soil was restored to original level after 180 d incubation. These results indicated that the sunflower oil had a great capacity to remove PAHs from contaminated soils, and sunflower oil solubilization can be an alternative technique for remediation of PAH contaminated soils.

Carbon↗

PubMed2006

Organic contaminant loads into the Western Mediterranean Sea: estimate of Ebro River inputs.

Annual input estimates for several organic contaminants from the Ebro River into the Northwestern Mediterranean Sea were carried out on the basis of monthly sampling from November 2002 to October 2003. Some organochlorine compounds (DDT and its degradation products, DDD and DDE, PCBs (9 congeners), HCB and gamma-HCH) were selected due to their reported occurrence in the river. Furthermore, some polar pesticides used in the Ebro Delta were also determined (atrazine, simazine, diazinon, fenitrothion and molinate). Concentrations ranged from 0.4 to 19.5 ng l(-1) for the organochlorine compounds (sum of particulate and dissolved phases) and from not detected (ND) to 170 ng l(-1) for the more polar pesticides, which were only found in the dissolved phase. The sum of PCB congeners (mean 8.9 ng l(-1)) showed the highest concentrations among the organochlorine compounds and atrazine (mean 82 ng l(-1)) among the polar pesticides. Based on the contaminant concentrations and on hydrological data, contaminant discharges into the sea were estimated amounting in total to 167 and 1,258 kg year(-1) of organochlorine compounds and polar pesticides, respectively. Furthermore, it was observed that PCBs, DDTs and HCB inputs were basically influenced by spate periods due to an increase in suspended particulate matter associated to runoff and sediment resuspension. Whereas for more water soluble contaminants, such as the agrochemicals, their seasonal use had a higher incidence in contaminant fluxes. Bulk chemical parameters such as SPM, DOC, POC, %OC, %ON and C/N ratio provided additional information on the organic matter sources. This provides a better understanding of the temporal variability of the contaminant concentrations.

Animals↗