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PubMed1962

Microbiological contamination of hospital air. I. Quantitative studies.

The levels of airborne contamination in various areas of two hospitals were determined during a 15-month sampling period, using Casella and Andersen volumetric samplers. Based on nearly 5,000 samples, the mean count per ft(3) ranged from 4.5 in obstetric-gynecology delivery rooms to 72.4 in waste-handling areas. The mean count for the entire hospital environment was on the order of 20 contaminants per ft(3); 48% were associated with particles >5 mu diam, 30% with particles between 2 and 6 mu diam, and 22% with particles <2 mu diam. The airborne contamination was influenced by traffic, activity, ventilation considerations, and gross surface contamination, but not markedly by seasonal changes. When suitable control measures were implemented, the level of contamination could be diminished and kept low.

Air Microbiology↗

PubMed2004

Two novel real-time reverse transcriptase PCR assays for rapid detection of bacterial contamination in platelet concentrates.

The incidence of platelet bacterial contamination is approximately 1 per 2,000 units and has been acknowledged as the most frequent infectious risk from transfusion. In preliminary studies, the sterility of platelet concentrates (PCs) was tested with an automated bacterial blood culturing system and molecular genetic assays. Two real-time reverse transcriptase PCR (RT-PCR) assays performed in a LightCycler instrument were developed and compared regarding specificity and sensitivity by the use of different templates to detect the majority of the clinically important bacterial species in platelets. Primers and probes specific for the conserved regions of the eubacterial 23S rRNA gene or the groEL gene (encoding the 60-kDa heat shock protein Hsp60) were designed. During the development of the 23S rRNA RT-PCR, problems caused by the contamination of reagents with bacterial DNA were noted. Treatment with 8-methoxypsoralen and UV irradiation reduced the level of contaminating DNA. The sensitivity of the assays was greatly influenced by the enzyme system which was used. With rTth DNA polymerase in a one-enzyme system, we detected 500 CFU of Escherichia coli or Staphylococcus epidermidis/ml. With a two-enzyme system consisting of Moloney murine leukemia virus RT and Taq DNA polymerase, we detected 16 CFU/ml. With groEL mRNA as the target of RT-PCR under optimized conditions, we detected 125 CFU of E. coli/ml, and no problems with false-positive results caused by reagent contamination or a cross-reaction with human nucleic acids were found. Furthermore, the use of mRNA as an indicator of viability was demonstrated. Here we report the application of novel real-time RT-PCR assays for the detection of bacterial contamination of PCs that are appropriate for transfusion services.

Bacteria↗

PubMed1995

Acanthamoeba, bacterial, and fungal contamination of contact lens storage cases.

BACKGROUND: Microbial corneal infection is the most serious complication of contact lens wear. Contact lens cases are a recognised potential source of pathogens associated with corneal ulcers. METHODS: This survey established the incidence of protozoal, bacterial, and fungal contact lens case contamination in 101 asymptomatic daily wear cosmetic contact lens wearers from a domiciliary contact lens practice. RESULTS: Eighty two (81%) contact lens cases were found to be contaminated, with 19 (19%) sterile. Of all contact lens cases, 78 (77%) grew bacteria, 24 (24%) fungi, and 20 (20%) protozoa. Acanthamoeba spp were isolated from eight (8%) contact lens cases. Fifty six (55%) contact lens cases yielded mixed bacterial contamination. This is the first contact lens case survey in which hydrogen peroxide disinfection was the major method of contact lens disinfection (75% of subjects) and no home made saline was used. All the contaminating organisms were shown to possess the enzyme catalase that breaks down hydrogen peroxide to oxygen and water. The polymicrobial nature of the biofilms found in many contact lens cases is illustrated electron micrographically. CONCLUSION: Based on data from this and previous studies, the authors conclude with recommendations for contact lens wearers: (1) regular scrubbing of contact lens case interior to disrupt biofilms; (2) exposure of contact lens case to very hot water (> or = 70 degrees C) will kill Acanthamoeba contaminants; (3) allow contact lens case to air dry between uses; (4) if hydrogen peroxide disinfection is preferred, use a two step system; (5) replace contact lens case regularly.

Acanthamoeba↗

PubMed2003

A preliminary investigation into bacterial contamination of Welsh emergency ambulances.

OBJECTIVES: The objective of this regional study across Wales was to perform a preliminary examination of Welsh emergency vehicles to determine levels of bacterial contamination. METHODS: Specific sites within emergency vehicles were swabbed, before and after vehicle cleaning, over a 12 month period, on a monthly basis. All swabs were sent to pathology laboratories for culturing and analysis. RESULTS: Results showed that most sites within emergency vehicles across Wales were contaminated with a range of bacterial species before vehicle cleaning. After vehicle cleaning, many sites in vehicles were still contaminated, and some sites that were previously uncontaminated, became freshly contaminated as a result of cleaning methods used. CONCLUSIONS: The authors conclude that the Welsh emergency vehicles examined exhibited an unacceptable level of bacterial contamination. This finding should be carefully considered and all attempts must be made to tackle the problem of vehicle cleanliness and infection control.

Ambulances↗

PubMed1996

Effect of pre-slaughter washing of lambs on the microbiological and visible contamination of the carcases.

Studies in four slaughterhouses with contrasting dressing systems showed that microbiological contamination with total aerobic bacteria and Escherichia coli was greater on carcases which had been washed before slaughter, irrespective of wool length, and was generally higher on carcases derived from woolly lambs than on those derived from shorn lambs. The effects of pre-slaughter washing on the forequarters compared with the hindquarters were not consistent, and this was attributed to differences between the dressing systems applied in the slaughterhouses. Over all trials the mean total aerobic count ranged from 3.45 to 5.36 log10/cm2, and the mean counts of E coli ranged from 0.39 to 2.11 log10/cm2. There was less visible contamination on the carcases of washed lambs than on those of unwashed lambs. The differences in contamination with wool were largely dependent on the level of contamination of individual carcases, whereas the differences in contamination with faecal material and dirt or sand were largely dependent on the prevalence of affected carcases. The use of pre-slaughter washing to compensate in visual terms for poor pre-slaughter presentation results in a detrimental effect on microbiological loads on ovine carcases.

Abattoirs↗

PubMed2004

Effect of U and 137Cs chronic contamination on dopamine and serotonin metabolism in the central nervous system of the rat.

Following the Chernobyl accident, the most significant problem for the population of the former Soviet Union for the next 50-70 years will be chronic internal contamination by radionuclides. One of the few experiments carried out in this field reported that neurotransmitter metabolism in the central nervous system of the rat was disturbed after feeding with oats contaminated by 137Cs for 1 month. The present study assessed the effect of chronic contamination by depleted U or 137Cs on the metabolism of two neurotransmitters in cerebral areas of rats. Dopamine and serotonin were chosen because their metabolism has been shown to be disturbed after external irradiation, even at moderate doses. Dopamine, serotonin, and some of their catabolites were measured by high-pressure liquid chromatography coupled with an electrochemical detector in five cerebral structures of rats contaminated over a 1-month period by drinking water (40 mg U.L -1 or 6500 Bq 137Cs.L -1). In the striatum, hippocampus, cerebral cortex, thalamus, and cerebellum, the dopamine, serotonin, and catabolite levels were not significantly different between the control rats and rats contaminated by U or 137Cs. These results are not in accordance with those previously described.

3,4-Dihydroxyphenylacetic Acid↗

PubMed1990

The use of trichothecene-contaminated grains in feeds.

A review is presented describing the relative efficiencies of the various technologies that have been proposed to permit incorporation of mycotoxin-contaminated grains into animal diets without adversely influencing growth rate or resulting in hazardous residues in edible animal tissues. When the degree of contamination is modest, it may be possible to dilute the contaminated materials with uncontaminated grain to lower the concentration of trichothecenes below the threshold of significant biological activity. A less useful alternative to dilution is the other mechanical approach of milling to remove the most heavily contaminated fractions of the grain. Chemical destruction of triochothecenes is also a possibility. An example is the use of sodium bisulfite treatment to destroy deoxynivalenol in contaminated corn. Such treatments may, however, reduce palatability and nutritional value. When the biochemical mechanism of trichothecene toxicity is known, in vivo therapeutic treatments may be possible. It has been shown, for example, that T-2 toxin-induced changes in brain prostaglandin production can be overcome by treatment with dexamethasone resulting in increased survival. A similar effect was seen using the selective platelet activating factor antagonist BN 52021. Another approach is the use of dietary treatments to either promote in vivo detoxification of mycotoxins or to reduce absorption from the digestive tract with the aid of nonnutritive binding agents.

Animal Feed↗

PubMed2000

Environment and contaminants in traditional food systems of northern indigenous peoples.

Traditional food resources of indigenous peoples are now recognized as containing a variety of environmental contaminants which reach food species through local or long-range transport avenues. In this chapter we review the published reports of contaminants contained in traditional food in northern North America and Europe as organochlorines, heavy metals, and radionuclides. Usually, multiple contaminants are contained in the same food species. Measurement of dietary exposure to these environmental contaminants is reviewed, as are major issues of risk assessment, evaluation, and management. The dilemma faced by indigenous peoples in weighing the multiple nutritional and socioeconomic benefits of traditional food use against risk of contaminants in culturally important food resources is described.

Chlordan↗

PubMed1992

Analysis of strike-through contamination in saturated sterile dressings.

The method of saturating gauze sponges directly in their wrapper was tested to determine strike-through contamination. Contamination occurred in 100% of the uncoated-wrapper sponges, regardless of exposure to Staphylococcus epidermidis or Escherichia coli. Among coated-wrapper sponges, 80% exposed to Staphylococcus epidermidis and 20% exposed to Escherichia coli demonstrated strike-through contamination. Coated-wrapper sponges had a significantly lower rate of contamination than uncoated-wrapper sponges when exposed to Escherichia coli. Occurrence of contamination of all sponges was significantly higher from Staphylococcus epidermidis. The findings render the popular practice of saturating gauze sponges in their wrapper unacceptable.

Bandages↗

PubMed1995

Strike-through contamination in saturated sterile dressings: a clinical analysis.

This multisite study examined the risk of strike-through contamination of 4" x 4" gauze sponges using a shortcut method of saturating sterile sponges directly on their wrappers. Sterile gauze sponges were saturated directly on their wrappers on hospital over-bed tables of postoperative general surgical patients. Cultures were taken at 0.5, 1, 3, and 5 minutes after saturation to ascertain whether strike-through contamination occurred. Saturated sponges showed significant microorganism growth when compared to expected zero microorganisms at all sampling times following saturation. Although microorganisms identified in strike-through contamination were not microbiologically or pathogenically threatening, the basic principle of asepsis was violated. There was no significant difference in strike-through contamination between sponges saturated on coated wrappers and sponges saturated on uncoated wrappers. Clinicians should be aware that coated wrappers do not provide a moisture-proof barrier against strike-through contamination. The findings suggest the shortcut method should not be used for saturating sponges.

Asepsis↗

PubMed2005

Comparison of urine contamination rates using three different methods of collection: clean-catch, cotton wool pad and urine bag.

Collecting uncontaminated urine specimens from infants is difficult. Commonly, an adhesive urinecollecting bag is used, which is uncomfortable. This study determined bacterial contamination rates using three methods of urine collection sequentially on the same infant (without known urinary tract infection)-clean-catch, cotton wool (sanitary) pad and urine bag. The study was undertaken in children under 3 years of age in the Institute of Maternal and Child Health of Pernambuco (IMIP), Recife, Brazil. Urine samples were analysed using phase contrast microscopy and routine culture. Culture of bacteria at any level was interpreted as a contaminated urine specimen. Cultures with > 10(5) colony-forming units/ml of one species by all three collection methods were regarded as true urinary tract infection and these children were excluded. Altogether, 534 urine samples from 191 patients were analysed. Median age was 2 months (1 day-36 months) and 124 (65%) were boys. Twelve children (6.3%) were considered to have true urinary tract infection, three were indeterminate and in 16 one or more samples were missing and all were excluded from analysis. There were more missing samples using the clean-catch method (12%) than when using the bag (4%) or pad (4%). Seventy-six of 160 (47.5%) children had evidence of bacterial contamination. Clean-catch specimens showed the least contamination (14.7%) and rates were similar between pads (29%) and bags (26.6%) (kappa = 0.40). Urine contamination rates were similar for sanitary pads and urine bags and significantly higher than for clean-catch (p<0.01). However, pads were a simple, non-invasive and comfortable alternative to bags.

Child, Preschool↗

PubMed2006

Study of Salmonella, Campylobacter, and Escherichia coli contamination in raw food available in factories, schools, and hospital canteens in Hanoi, Vietnam.

This study on the contamination rates of raw foods available in factory, school, and hospital canteens in Hanoi, Vietnam, with the bacteria of Salmonella, Campylobacter, and Escherichia coli (E. coli) was carried out between 2003 and 2004. A total of 177 raw food samples of vegetables, meat (beef and pork), fish, and poultry were examined to provide baseline data for evaluation of microbiological risks in general, and identification of potential vehicles for pathogenic cross-contamination in canteens. The study confirmed that unprocessed fish and poultry are likely to be contaminated with Salmonella and in the absence of proper kitchen hygiene and may contaminate processed foods. Raw poultry samples were highly contaminated with E. coli (45%), Campylobacter jejuni (C. jejuni) (28.3%), and Salmonella (8.3%) and classified as high-risk food. E. coli was also detected in raw meat, fish, and vegetables with the rate of 21.3%, 6.6%, and 18.5%, respectively. This article confirmed the importance of hygienic working practices when preparing food.

Animals↗

PubMed1979

Selenium 75 contamination in iodine 131 solutions.

During investigations on athyreotic patients given large test doses of 131I, whole-body counting has shown the presence of 75Se contamination in some patients. The investigations were carried out to measure the small long-term component of 131I retention in such patients. In an earlier paper (Smith and Edmonds, 1977), we concluded that the effects of 75Se contamination were negligible in the patients described. Subsequent studies on a further small group of similar patients, however, have indicated that the levels of contamination are variable, and this report is intended as a warning of the possibility of measurement error due to this contamination in metabolic studies similar to those to be described. The effects of 75Se contamination observed in two out of five patients studied have been assessed.

Drug Contamination↗

PubMed2000

Serum polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans among people eating contaminated home-produced eggs and beef.

We compared serum polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) among residents of two homes to levels among age- and sex-matched comparison subjects. The residents of the two homes consumed contaminated eggs and beef from animals raised at the homes. The animals had greater soil contact than those raised with conventional commercial husbandry practices. The comparison subjects were from a similar rural area, but did not consume home-produced beef and eggs. Serum levels of 2,3,7, 8-substituted tetra-, penta-, and hexaCDDs and penta-, hexa-, and heptaCDFs were increased between 2- and 6-fold in residents from one home; contaminated eggs and beef were consumed by residents for 2-15 years. Elevations were less for those in the other index home, where only home-produced eggs were consumed for 2 years; a 3-fold elevation of 1,2,3,7,8,9-hexaCDD as compared to controls was most apparent. Very strong bivariate correlations among all of the 2,3,7, 8 penta- and hexaCDDs/CDFs were observed. The elevations observed verify that PCDD/PCDF-contaminated food contributed to the body burden of these compounds. The blood levels among the highest exposed participants are generally higher than those observed in other studies of U.S. contaminated-fish consumers and higher than average adipose tissue levels observed in U.S. urban populations. There are sufficient animal toxicologic and human epidemiologic data to recommend that exposures be reduced. In the study area, pentachlorophenol and pentachlorophenol incineration sources have been identified, and the animal contamination and blood elevations probably reflect these sources. Soil reference values and site-specific risk assessments should include estimates of exposures to contamination in home-produced animal products. Such estimates can be verified with limited PCDD/PCDF sampling of animals and humans.

Adolescent↗

PubMed1997

Evaluation of the population distribution of dietary contaminant exposure in an Arctic population using Monte Carlo statistics.

Organochlorines and heavy metals have bioaccumulated in Arctic wildlife, which is an important food source for the Inuit. In this study, we have developed a statistical model to describe the population distribution of contaminant exposure and the usual intake of the high-end contaminant consumers. Monte Carlo methods are used to account for variations due to seasonal dietary pattern and contaminant concentrations. Distribution of the dietary intake of the contaminants of most concern-mercury, polychlorinated biphenyls (PCBs), chlordane, and toxaphenes-are described. Over 50% of the residents had dietary exposure levels exceeding the tolerable daily intake or provisional tolerable daily intake for Hg, toxaphene, and chlordane (83, 91, and 71% for men and 73, 85, and 56% for women, respectively). The high-end consumers (i.e. the 95th centile) have intake levels 6 times higher than the provisional tolerable weekly intake of Hg, and over 20 times the tolerable daily intake of chlordane and toxaphene. Assessment of health risks of the relative high contaminant exposure in this community must also consider the nutritional, economical, cultural, and social importance of these traditional foods. A comprehensive risk management scheme has yet to be developed.

Adult↗

PubMed1997

[Evaluation of lead and cadmium levels in milk in environmental contamination in the Vale do Paraíba Region, southeastern Brazil].

INTRODUCTION: A factory producing lead ingots, located in Caçapava, caused lead and cadmium contamination of the environment, in the Paraiba Valley region of Southeastern, Brazil, through the discharge of industrial waste and the recycling of batteries. The factory, set in a rural, dairy cattle breeding area, worried sanitary authorities who envisaged the possibility of these metals' having entered the food chain. For the purpose of assessing the levels of contamination of the milk produced in the region, due to the cattle's possible consumption of contaminated grass and water, the amounts of cadmium and lead present in the milk were verified. MATERIAL AND METHOD: Major producers, covering an area of up to 20 km from the contaminated source, authorized collection of 218 samples of both pasteurized and non-pasteurized milk, which were analysed. Lead and cadmium levels were determined by flame atomic absorption spectrophotometry, the lead being pre-concentrated by complexation with APDC (ammonium 1-pyrrolidinecarbodithioate) and further extraction with isobutyl methylketone. RESULTS AND CONCLUSIONS: Of the total number of samples, 43 presented lead levels over the maximum limit of 0.05 mg/kg established by Brazilian legislation. The median value found for lead was 0.04 mg/L. The variance analysis, with 95% confidence level, found no significant difference among the types of milk studied with regard to lead levels. As for cadmium, all samples showed levels below the 0.02 mg/L quantification limit of the method. In spite of the environmental contamination, the levels of cadmium found in the milk were below the 1.0 mg/kg limit established by Brazilian legislation.

Animals↗

PubMedDate not supplied

Effect of prior serial in vivo passage on the frequency of Salmonella enteritidis contamination in eggs from experimentally infected laying hens.

Experimental infection models are valuable tools for understanding and preventing the deposition of Salmonella enteritidis inside eggs. Oral inoculation is believed to closely simulate naturally occurring S. enteritidis infections of chickens, but oral infection studies have often generated relatively low frequencies of egg contamination. The present study assessed whether repeated in vivo passage of an S. enteritidis strain could affect its ability to cause egg contamination in experimentally infected hens. The incidence of egg contamination was determined in groups of hens inoculated orally with either a phage type 13a S. enteritidis strain or derivatives of this parent strain that were obtained by three successive rounds of passage and reisolation from tissues of infected hens. Passaged S. enteritidis isolates recovered from ovaries and oviducts induced a significantly higher incidence of egg contamination (16.97%) than was attributed to the parent strain (8.27%). However, passaged S. enteritidis isolates recovered from livers and spleens were not associated with a significantly increased frequency of deposition in eggs. By either inducing or selecting for the expression of relevant microbial properties, passage of S. enteritidis through reproductive tissues of chickens may be useful for improving the efficiency at which experimental infection models produce egg contamination.

Administration, Oral↗

PubMed2006

Comparison of surface contamination with cyclophosphamide and fluorouracil using a closed-system drug transfer device versus standard preparation techniques.

PURPOSE: A comparison was conducted of the levels of surface contamination with two commonly used antineoplastic drugs, cyclophosphamide and fluorouracil, on countertops, floors, and hood surfaces in three oncology pharmacies following preparation with standard hazardous drug (HD) preparation techniques, or a closed-system drug transfer device (CSTD) in conjunction with standard HD preparation techniques, or a CSTD in conjunction with standard HD preparation techniques but prepared on a countertop outside the biological safety cabinet (BSC). METHODS: Wipe samples of the various surfaces in each pharmacy were obtained biweekly for 12 weeks (six samples) to establish a baseline. Following implementation of the CSTD, an additional six biweekly samples were collected. The CSTD was then removed, and a final six samples were collected again using standard preparation techniques. During the CSTD Phase, fluorouracil was prepared on the countertop outside the BSC. RESULTS: During the 36-week study, 342 samples were collected. A total of 8% positive fluorouracil wipe samples were found in the three pharmacies. The proportion of positive fluorouracil samples was significantly less in the CSTD Phase than in the control phases (p = 0.0002). There were 324 (95%) positive cyclophosphamide wipe samples. The median surface contamination was significantly different across the three phases (p < 0.00001). This was consistent at all sites, for both the BSC work surfaces and countertops. Contamination on floors adjacent to the BSCs was not consistently reduced. CONCLUSION: The use of a CSTD in the BSC in conjunction with standard HD preparation techniques significantly reduced cyclophosphamide surface contamination as compared to standard techniques alone. Preparation of fluorouracil outside the BSC using the CSTD did not result in significant analytically detectable contamination on the countertops.

Antineoplastic Agents↗