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PubMed2001

Contamination and survival of Pseudomonas aeruginosa in hospital used sponges.

The microbial contamination of in-use sponges was investigated. Of the sixty sponges examined, 51 (85%) were contaminated with 10(3)-10(9) colony forming units (CFU) per sponge. Pseudomonas aeruginosa was isolated from sixteen (26.7%) of the sixty sponges. P. aeruginosa survived for 2 months in contaminated sponges which were left at room temperature and became dry to the touch. The susceptibility of sponges to P. aeruginosa contamination should be recognized. Once sponges are contaminated with P. aeruginosa, eradication of this organism is difficult even if the sponges are dried.

Cell Division↗

PubMedDate not supplied

Extents of contamination of top milk and their determinants in an urban slum of Varanasi, India.

A community based study to examine the extent of contamination of supplementary milk feeds of 149 children aged 6-24 months was conducted in a semi urban slum of Varanasi, India. Out of 201 children, 149 top milk samples were collected directly from the feeding utensils into a sterile vial and subjected to bacteriological analysis. Overall, 53.7% of milk samples were contaminated by bacteria and among them 16.1% were potentially enteropathogenic in nature. The distribution of pathogens was E. coli (13.4%), Klebsiella spp (5.4%), Enterobacter spp. (5.4%), Pseudomonas aeruginosa (4.7%), Shigella spp. (2.7%) and others (22.1%). The rate of contamination was significantly higher (p < 0.001) in lower income group (73.4%), lower caste (69.6%) and in case of illiterate mothers (69.3%). Bivariate analysis indicated that wherever the afore mentioned parameters of hygiene were adverse, isolation rates increased multifoldely. Multiple logistic regression analysis indicated that the probability of a milk sample being positive for bacterial contamination was higher by 20 times when unclean utensils were used, by 3 times if mothers hands were dirty and by 2.8 time if the mothers were illiterate. The odds of contamination by pathogens was 25.7 times higher if the feeding utensils were dirty.

Animals↗

PubMed2001

False-positive growth of Mycobacterium tuberculosis attributable to laboratory contamination confirmed by restriction fragment length polymorphism analysis.

SETTING: Despite the high prevalence of tuberculosis in Korea, false-positive cultures have not yet been reported. At Pusan National University Hospital, in which positive mycobacterial culture specimens were 2.8 daily on average, 12 specimens from 10 patients requested on the same day were positive for Mycobacterium tuberculosis. OBJECTIVE: To identify an episode of laboratory cross-contamination in a tertiary care hospital. DESIGN: All isolates were analyzed by restriction fragment length polymorphism, and patients' medical records were reviewed. RESULTS: All isolates from 10 patients with supposed cross-contamination were identical. Anti-tuberculosis drugs were administered to two patients unnecessarily, resulting in adverse drug reactions in one patient. In one patient who had known tuberculous empyema, the medication course was probably lengthened unnecessarily. CONCLUSIONS: An episode of laboratory cross-contamination in mycobacterial cultures occurred, possibly due to droplets splashed from a sample in a centrifuge tube. Consequently, the aerosol soiled the tip of the dispenser and contaminated the following specimens sequentially. This episode of laboratory cross-contamination resulted in some modifications in our methods of specimen processing and interpretation of the results.

Adult↗

PubMed2001

Bacterial contamination of dental handpieces.

Bacterial contamination of water- and air-lines was investigated after artificial contamination and clinical use of dental handpieces. The effect of lubrication, disinfection and autoclaving on this contamination was also addressed. Bacterial growth was recorded in both the air- and water-lines during clinical and artificial contamination, with water-lines showing heavier contamination than air-lines. External and internal surfaces of handpieces still yielded bacterial growth after lubrication and disinfection, while heat sterilisation (autoclaving) rendered both internal and external surfaces sterile.

Air Microbiology↗

PubMed2002

Potential food contaminants and associated health risks.

The potential toxicants in food are derived from natural or industrial sources. Compounds like lectins and glycoalkaloids that are toxic to man are naturally present in some vegetables like potatoes or legumes. A wide variety of marine toxins mostly produced by dinoflagellates occurring secondarily in molluscs and mussels are usually ingested by human beings causing poisoning. On the other hand, toxic compounds find their way into food during manufacture, storage, or transportation. These include largely the industrial contaminants, persistent organic pollutants (POP), pesticides, heavy metals, and toxins of fungal and bacterial origin. Further, toxic compounds like higher alcohols may be produced as byproducts during processing. Migration of compounds from packaging materials into packaged food like contamination with lead from solder in certain metal cans is well known. Additives (emulsifiers, preservatives, and antioxidants) could also influence the quality of foods. Solvent residues may find their way into food as a result of their use in extraction processes like the use of trichloroethylene and methylene chloride in decaffeination of coffee. In addition, poor hygiene, storage, and preparation may also lead to food contamination by various microbes and ova or cysts of nematodes. The problem of food contamination can be overcome to a great extent by regular surveillance and monitoring programmes and strict implementation of food and adulteration act. In the present review some of these aspects of food contamination have been discussed in detail.

Animals↗

PubMed2002

Bacterial contamination of colostrum fed to newborn calves in Québec dairy herds.

A convenience sample of 234 colostral specimens, collected directly from the nursing bottle immediately prior to the first feeding, was studied. Samples originated from 6 farms and were collected over 24 months. Routine bacteriologic techniques were used to quantify the bacterial load of the colostrum, as well as to identify the bacteria. Overall, at least 1 microorganism was cultured from 221 colostral samples (94.4%). By using the upper tolerance level of 100,000 bacteria/mL, 84 samples (35.9%) were considered contaminated. Staphylococcus spp. (57.7%), gram-negative rods (47.9%), coliforms (44.0%), and Streptococcus uberis (20.5%) were among the most frequently isolated bacteria. The relative risk (RR) of contamination with more than 100,000 bacteria/mL was significantly greater in warm months [RR = 2.55, 95% confidence interval (CI): 1.63 to 4.02] than in cool months and in colostrum offered to male calves (RR = 1.55, 95% CI: 1.09 to 2.20). Bacterial load was also associated with the farm of origin (P < 0.0001). When assessing colostrum management, one should consider bacterial contamination. Multiple factors are likely associated with the degree of contamination, and farm-specific factors may be important. Further studies are necessary to evaluate the impact of bacterial contamination of colostrum on neonatal health.

Animals↗

PubMed2003

Quantification of incidental needle and suture contamination during strabismus surgery.

PURPOSE: To quantify the level of bacterial contamination of needles and sutures immediately after use in strabismus surgery. METHODS: Strabismus surgery was performed on 56 eyes from 31 pediatric strabismus surgical cases. Preoperative site preparation included instillation of 5% povidone-iodine in the conjunctival fornices in all cases. A total of 124 needles and 127 sutures were cultured immediately after final scleral passage. RESULTS: Seventeen of the 31 cases (54.8%) produced at least one positive specimen. Nineteen per cent of the needles and 25.2% of the sutures were culture positive. The bulk of positive specimens (96.7% of needles, 91.3% of sutures) produced 3 or less colony forming units, corresponding to 7 or less total viable organisms per needle or sutures in accordance with the dilution scheme. Coagulase-negative staphylococci overwhelmingly predominated. CONCLUSIONS: Needles and sutures used in strabismus surgery can become contaminated during surgery despite preoperative povidone-iodine preparation. The number of viable bacterial contaminants is usually below the level known to consistently produce experimental endophthalmitis. However, a few needles and sutures carried a high contaminant load, suggesting the possibility that contaminated needles and sutures could potentially cause postoperative intraocular infection.

Adolescent↗

PubMed2003

[Quantification of the probability of milk contamination by Listeria monocytogenes during manufacture of hard cheese].

BACKGROUND: The present work is concerned with the probability of contamination by Listeria monocytogenes in the artisanal manufacture of Swiss Emmental hard cheese made from raw milk. The simulation model follows the evolution of the contaminant flora from raw milk at the farm to milk mixing, storage at the cheese factory and to the cheese manufacturing process. METHODS: The simulations are based on models of predictive microbiology, namely the exponential growth model of bacteria including the lag-time, a cardinal growth model and a Log-linear model of thermal deactivation of bacteria. RESULTS: The results of the actual simulation indicate that the contamination of milk at the farm is a rare event (P=0.0036), but the mixing of milk at the cheese factory leads to a higher probability of contamination of cheese milk (P=0.07). Elevated bacterial concentrations are mainly due to cases of mastitis involving Listeria monocytogenes. The decline in bacterial counts during cheese manufacture depends on the curing temperature (52-54 degrees C) and varies between 1.5 and 3.2 Log cfu/ml. Freshly manufactured Emmental-cheese made from contaminated raw milk is expected to have only 4.6 cfu of heat injured Listeria monocytogenes /kg cheese mass in the press. CONCLUSION: Depending on listeria evolution, from the press to the product consumption, consumer exposure has been evaluated and might result in 1 to 10 Listeria monocytogenes per portion of cheese. The bacterial presence could be due to recontamination during packaging, distribution and cheese preparation by the consumer. Based on the presented data and estimations, it is concluded that the consumption of traditionally/artisanal manufactured Swiss Emmental hard cheese presents an extremely low, but existent risk, especially for people with a deficient or diminished immune system.

Animals↗

PubMedDate not supplied

Bacterial contamination rate of eyedrops: comparison of a hospital and a private outpatient center in Kermanshah, Iran.

Bacterial contamination rate of eyedrops: comparison of a hospital and private outpatient ophthalmology centers of Kermanshah, Iran. Eye drops are sterile solutions with different clinical effects. Like any therapeutic medication, they should be administered using aseptic technique and stored in a way that prevents bacterial contamination. In our hospital and local private clinical settings, some cases of bacterial keratitis are thought to be due to eyedrops, which are used on multiple patients and at some point become contaminated. This study was done to compare the bacterial contamination rate in an educational hospital with private ophthalmic centers and attempt to identify the route of contamination and consequently, a method to resolve or reduce the problem.

Cross Infection↗

PubMed2004

Influence of salivary contamination on marginal microleakage of pit and fissure sealants.

PURPOSE: To assess quantitatively the influence of salivary contamination in vitro on marginal microleakage of pit and fissure sealants. METHODS: Forty-eight sound human third molars were selected and assigned to three groups: 1) Fluroshield (F), 2) Single Bond + Fluroshield (SBF) and 3) Ketac-fil (KF). Each group was divided into two subgroups: control (C) and with salivary contamination (SC). The occlusal surfaces were etched with 40% polyacrylic acid for 10 seconds or 37% phosphoric acid for 30 seconds, for either glass-ionomer or resin-based sealants, respectively. Specimens were contaminated with 0.25 mL of fresh human saliva for 20 seconds and dried afterwards. The sealants were placed and samples were thermocycled, immersed in a 0.2% Rhodamine B solution for 24 hours, embedded in acrylic resin and serially sectioned. The sections were viewed under an optical microscope connected to a computer and a video camera, and the images obtained were digitized. The extent of dye penetration along buccal and lingual slopes was measured in millimeters, using specific computer software, and converted into percentage, according to the fissures extension. RESULTS: The microleakage means (%) were: F/C:0 (+/- 0); F/SC: 31.71 (+/- 31.69); SBF/C: 0 (+/- 0); SBF/SC: 0 (+/- 0); KF/C: 0.98 (+/- 2.79) and KF/SC: 11.82 (+/- 15.45). ANOVA and Tukey test showed that salivary contamination provided significant increase in microleakage. Under salivary contamination, only SBF provided complete marginal sealing. When F and KF were compared, the glass-ionomer cement yielded the best sealing.

Acid Etching, Dental↗

PubMed2004

[Survey and analysis on sterigmatocystin contaminated in grains in China].

In order to determine the Sterigmatocystin (ST) contaminated in grains by indirect competitive enzyme link immune sorbent assays (IC-ELISA), 1580 samples including wheat, corn and rice were taken from 12 provinces located in East-north, west-north, west-south, east and central China. Results showed that the average contaminated content of ST in wheat, corn and rice was 68.9 ug/kg, 32.2 ug/kg and 13.9 ug/kg respectively. Also, the contaminated rate was 98%, 89% and 72% respectively. The contaminated content and rate of ST was highest in wheat followed by corn and the rice ranged in third that was statistically highly significant. Severity of contamination was different in different geo-regions with higher in east China and Western China that in north-east China, central China and south-western China that were statistically highly significant.

China↗

PubMedDate not supplied

A novel approach to the statistical evaluation of media fill tests by the difference from no contamination data.

It is obvious that, in the media fill test and process simulation test, positive numbers in total fills should not have any significant difference from zero or asepsis. There are many reports concerning the definition of "sterility" or "asepsis." However, any scientific and practical methods to demonstrate "no significant difference from zero" have not been reported up to now. The existing criteria, such as "less than 0.1%," "less than 0.05%," and "less than two positives" are not appropriate to assure the integrity of processes, and sometimes lead to erroneous results. The purpose of this report is to demonstrate novel, reasonable and practical methods and criteria based on scientific and statistical consideration. According to the ISO 13408-1 Aseptic Processing of Health Care Products, Part 1 (1998), General Requirement for Aseptic Processing, the action level for the number of positive units in media fill tests is specified as 0.1%, and the alert level is 0.05%. In this paper it is shown that the existing ISO standard and other official methods are inappropriate in that zero contaminated units (sterile product) is outside the confidence range of probable distribution of contaminated units, even though the contaminated units are less than 0.1% in larger numbers of fills, and even less than 0.05%. This indicates that the limit of 0.1% or 0.05% is inappropriate in cases of larger numbers of fills. For sterile products, the number of contaminated units other than "zero" at the statistical confidence range must be judged to be contaminated units in process and as non-sterile. In order to harmonize this criteria-"no significant difference from zero"-with the existing criteria, the new criteria may be combined with only the existing criteria of 0.05% in smaller number of fills.

Drug Contamination↗

PubMedDate not supplied

Analysis of possible cross-contamination with the Venturi system atomizer.

BACKGROUND: The physics behind the Venturi atomizers suggest a possibility of bacterial colonization and the potential for patient cross-contamination. A protocol for use of the atomizer and clinically appropriate demonstration of cross contamination has not been established. METHODS: Three sterilized atomizers filled with a solution of 2% Pontocaine and 1% ephedrine (two test and one control) were used during a 5-day study period. Clinic staff was instructed to (1) use a nozzle tip, (2) use a nasal speculum, (3) avoid contact between the atomizer and the patient, and (4) apply a continuous, <1-second spray to the nasal cavity. Samples were obtained from each of the atomizers three times per day and plated on chocolate agar plates. The number and type of bacterial colony were registered. RESULTS: No respiratory pathogens grew from any of the 45 plated samples. Nine of 30 experimental atomizer samples produced 12 bacterial colonies. Of the 12 bacterial colonies obtained, 6 colonies of coagulase-negative Staphylococcus, 5 colonies of Corynebacterium sp., and 1 colony of Bacillus sp. were identified. One of 15 plated control atomizer samples produced two colonies of coagulase-negative Staphylococcus. An average of 1.3 colonies per positive test plate and an average of 2.0 colonies per positive control plate were identified. There was no evidence of an increasing number of colonies per plate or persistence of any particular bacteria identified over time to suggest contamination or colonization of the system reservoir. CONCLUSION: There is no risk of cross-contamination of patients with the use of the Venturi system atomizer as outlined in this study. Culture results from this study were consistent with random culture contamination during the plating and/or culturing period. There was no evidence to support the idea of bacterial colonization of the atomizers. Continued use of the Venturi system atomizer is an acceptable practice.

Administration, Intranasal↗

PubMed1991

Bovine viral diarrhea virus contamination of nutrient serum, cell cultures and viral vaccines.

Bovine viral diarrhea virus (BVDV) infection is common in the bovine population. Infection in utero leads to virus and antibody contamination of the fetal bovine serum used in cell cultures. These contaminants can interfere with diagnosis of viral infection. The high frequency of virus and antibody detection in individual animal or small pool samples suggests that any large pool of unscreened sera will be contaminated. Infection of cell cultures with BVDV can lead to interference with the growth of other viruses. Vaccine produced on contaminated cells may in turn be contaminated, leading to seroconversion or disease in the vaccine. The safety, purity, and efficacy of viral vaccines require BVDV testing of ingredients, cell substrates and final product. Methods for detection of BVDV in nutrient serum, cell cultures, seed viruses, and viral vaccines, and the frequency of their detection at the National Veterinary Services Laboratories are discussed.

Animals↗

PubMed1991

Evaluation of factors influencing ampoule secondary particulate contamination. A strategy for its reduction in small volume parenterals.

In this paper, we evaluated the influence of some glass ampoules characteristics that are critical as far as secondary particle contamination (visible and sub-visible) of small volume parenterals. Following characteristics were considered: snap-opening system (colour-break scoring and o.p.c.); break-point strength (high and low); dimensional characteristics (three types D1, D2, D3). According to the proper statistical design, 18 different batches of 2 ml ampoules filled with water for injection were manufactured; then sub-visible and visible particulate contamination generated on snap-opening the ampoules were examined. Sub visible particle counting was performed by the light-blockage method and visible particles counting by the membrane-filtration method. With regard to sub-visible particles, statistical analysis showed significant interactions of break-point strength with both ampoule dimensional characteristics and the type of snap-opening system. Break-point strength seems to have the greatest influence on the level of particulate contamination. Differences in ampoule snap-opening systems and dimensional characteristics exert a significant effect on the level of particle contamination only at high break-point strength. With regard to visible particles generated on snapping the ampoules, data are consistent with the findings of sub-visible particulate contamination. Ampoules manufactured according to DIN dimensional characteristics and with an o.p.c. snap-opening system provide the lowest particle burden.

Drug Contamination↗

PubMed1990

Biological responses of sheep treated with endotoxin-contaminated superoxide dismutase and endotoxin preparations.

The purpose of this study was to evaluate the biological response of sheep to different doses of endotoxin and endotoxin-contaminated enzyme preparations. The enzyme used in this experiment was superoxide dismutase (SOD), as it is currently being used in many different experiments and because several preparations were found to be heavily contaminated with endotoxin. A group of ewes were injected intravenously with a variety of different treatments. Peripheral blood was used to determine the total number of leukocytes, a differential cell count to find out the numbers of polymorphonucleocytes (PMN) and monocytes (M), and to measure the concentration of 15-ketodihydro-PGF2 alpha. In addition, rectal temperature was recorded. Treatments included saline (control), Pharmacia-Chiron's Cu/Zn-SOD (r-hSOD, 8 mg/kg), Sigma's bovine SOD (bSOD, 8 mg/kg), Grünenthal's bSOD (8 mg/kg), various doses of Salmonella typhimurium endotoxin (1000, 200, 100, 50, 20, 10, 5, and 1 ng/kg), and a mixture of endotoxin (200 ng/kg) plus r-hSOD (8 mg/kg). Results indicate that sheep react to endotoxin-contaminated SOD preparations with an endotoxemia which is similar to that seen in animals receiving endotoxin alone. This endotoxemia includes, among other things, a rise in rectal temperature, a peak in the PGF2 alpha metabolite, and an increased PMN/M ratio. Endotoxin administered at doses of 50 to 200 ng/kg also caused the expected signs of endotoxemia. At 1000 ng/kg endotoxin actually led to a decreased rectal temperature. This may be due to a type of endotoxemic shock, resulting in a decrease in peripheral blood circulation. Low doses of endotoxin (10, 5, and 1 ng/kg) caused a leukocytosis via increases in PMN; no greater changes in rectal temperature or the PGF2 alpha metabolite were noted. The combination of r-hSOD with 200 ng/kg of endotoxin caused an endotoxemia similar to that caused by 200 ng/kg of endotoxin alone. In conclusion, if an endotoxin-contaminated SOD-preparation was used to study the efficacy of SOD, there would be a serious risk of interaction by the endotoxins. In such a case it would be impossible to distinguish the effects of the endotoxin from those of the preparation itself. It is therefore important that researchers are alert to the problem of endotoxin contamination.

Animals↗

PubMed1989

[Aspects of long-term ingestion of contaminated food by cattle and game].

A radioactive contamination monitoring system of the Czechoslovak Federal Ministry of Agriculture and Food is described, including measuring and calibration methods and the monitoring results. Cesium contamination higher than the international derived intervention level was found only in game. The reasons were as follows: uncultivated green fields, forest herbage and needle-leaves are sufficient sources of game contamination; there exist evident differences between continuous ingestion of contaminated or mixed feed with respect to the cesium contamination of tissues.

Animal Feed↗

PubMed1988

[Bacterial contamination of the inspiratory circuit of artificial ventilation apparatus: influence of the frequency of circuit renewal and the duration of ventilation].

In a study concerning contamination of artificial ventilators (Drager model UV1), the influence of 2 parameters was assessed: the frequency of changing the circuit (2 and 4 days) and the interval between admission of the patient into the intensive care unit and obtaining the sample. As a function of these variables, 4 groups of 15 patients each were constituted. The levels of contamination noted at 4 sites in the inspiratory phase tubing (cascade humidifier, condensate collector, tubing nearest to the patient and tubing nearest to the humidifier) and in the gas flow showed no significant difference between the groups, regardless of whether the circuit was changed after 2 or 4 days, or whether the patient had been recently admitted to the department or had been there for at least 6 days. Quantitative and qualitative study of bacteria showed that the one(s) contaminating the inspiratory phase tubing were the same as the one(s) colonizing the tracheal secretions of the patient, and that the most contaminated areas were those nearest to the patient (proximal tubing, collector), which confirms the retrograde contamination of the circuit.

Bacterial Infections↗