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At least 19 recordsLinked to original sources
PubMed1979

[On the contamination of the citric acid fermentation. I. The contamination by representatives of Enterobacteriaceae (author's transl)].

Among the most dangerous bacterial contaminations of the citric acid fermentation is the so-called brown contamination, which is called forth by non pathogenic representatives of Enterobacteriaceae like Escherichia coli, Aerobacter aerogenes, Enterobacter cloacae and Proteus vulgaris, while other bacteria do not produce the mentioned contamination. There is given a comprehensive characterization of the brown contamination. Enterobacteriaceae interrupt the growth of the mycelium of the mold Aspergillus niger and stop the production of citric acid, produce a characteristic repugnant smell and reduce nitrate to nitrite. In a case of weak contamination the phenomena of the brown contamination do not appear, but the yield of citric acid is rather low. The contamination may be transferred successfully within the first 24 hrs. of incubation. The effect of the bacteria is determined by their virulence and some other factors.

Aspergillus niger↗
PubMed1989

Microbial contamination of arterial infusions used for hemodynamic monitoring: a randomized trial of contamination with sampling through conventional stopcocks versus a novel closed system.

Arterial catheters are now commonly used to monitor blood pressure and obtain blood samples for arterial blood gas and other laboratory determinations. Stopcocks inserted into the pressure monitoring circuit have been the primary means of obtaining blood from arterial catheters. However, these stopcock systems have been associated with nosocomial contamination and bacteremias. Because of the problems of bacterial contamination and blood wasting with the stopcock sampling systems, we compared the frequency and extent of contamination of external sampling ports and the monitoring tubing fluid in stopcocks with that of a novel closed needle-sampling system (Lab-Site, Migada Ltd, Rehovot, Israel), incorporated into pressure monitoring tubing (Abbott Laboratories Inc., North Chicago, Illinois). We found that use of the novel sampling system resulted in significantly fewer episodes of internal bacterial contamination of the arterial monitoring line (7%) than did the use of a stopcock system (61%). External contamination of the sampling port was also lower in the novel system (8%) than in the stopcock system (37%). This suggests that the closed system may reduce the risk of nosocomial infections in patients requiring arterial pressure monitoring.

Adult↗
PubMed1975

Nationwide epidemic of septicemia caused by contaminated intravenous products: mechanisms of intrinsic contamination.

Between 1 July 1970 and April 1971, in many hospitals in this country, there were outbreaks of nosocomial septicemia caused by Enterobacter cloacae of E. agglomerans (formerly Erwinia, herbicola-lathyri). All of these hospitals used infusion products manufactured by one company, Abbott Laboratories, and all affected patients had onset of septicemia while receiving the company's infusion products. Septicemia was epidemiologically and microbiologically traced to intrinsic contamination of the company's screw-cap closure for infusion bottles which was sealed with a newly introduced elastomer liner. Epidemic organisms were isolated from these closures. Investigations both in the laboratory and in the manufacturing plant into the mechanism of contamination of these products revealed the following. (i) Epidemic strains were present in numerous areas throughout the manufacturing plants. (ii) Viable microorganisms gained access to the interior of screw-cap closures after the autoclave step of production. (iii) Cooling closures actively drew moisture through the thread interstices into the inner-most depths of the closure. (iv) Transfer of contaminants from closures to fluid was easily effected by simple manipulations duplicating normal in-hospital use. (v) The red-rubber liner used in the company's screw-cap closures before the introduction of elastomer contained a broad-spectrum antimicrobial inhibitor. The findings from this epidemic and the associated studies show that the screw-cap closure as it is now designed cannot be considered secure for products that must remain sterile.

Cross Infection↗
PubMedDate not supplied

In vitro contamination of "piggyback/heparin lock" assemblies: prevention of contamination with a closed, positive locking device (Click-Lock).

Direct contact and airborne transmission are established modes of microbial contamination of standard intravenous (iv) assemblies such as piggyback and heparin lock. In this study, 60% of the standard iv assemblies inoculated with Staphylococcus aureus (S. aureus) at the barrel of their exposed needle grew these organisms when cultured in a Soy Casein Digest Broth (SCDB). Also, 40 closed, positive locking iv assemblies (Click-Lock) were inoculated at possible contamination sites, and none of these assemblies grew S. aureus in a SCDB. These in vitro studies suggest that a closed, positive locking iv assembly such as the Click-Lock device may substantially reduce, and potentially prevent contamination of iv systems.

Culture Media↗
PubMed1978

Bacterial contamination in a modern operating suite. 4. Bacterial contamination of clothes worn in the suite.

Clean clothes in the staff dressing rooms were heavily contaminated with bacteria, mainly Bacillus sp., but Staphylococcus aureus were found on 14% and Clostridium sp. on 10% of the garments examined. A comparison of the occurrence of Staph. aureus on shirts worn by staff in wards and operating departments showed ward shirts to be contaminated more heavily and with more strains. Examination of sterile gowns worn by surgeons showed that 70% were contaminated with Staph. aureus after operation. Of the strains isolated 31% were identical with those carried by the surgeon or by the patient operated on, but for the remainder no source could be found.

Bacillus↗
PubMed1992

Limiting bacterial contamination of enteral nutrient solutions: 6-year history with reduction of contamination at two institutions.

Running enteral nutrient solution (ENS) bacterial contamination logs that were collected over a 6-year time frame are presented. At hospital A, reconstituted ENS were prepared by the pharmacy department in bulk and were frozen in the final container. These solutions were cultured and counted after 12 hours of storage at room temperature to stimulate this institution's hang time. Major reductions in ENS bacterial counts occurred after improvements in sanitation, a reduction in solution hang time, the conversion to the use of sterile water for dilution and reconstitution of ENS, and most dramatically, after the incorporation of a preservative (potassium sorbate) to reconstituted ENS. At hospital B, ENS usage consisted of canned feedings that were prepared by nursing personnel and were transferred to the feeding container at the bedside. Reductions in final counts of contamination of ENS occurred after procedural changes, which included container changes every 24 hours, use of sterile water for dilution, cleansing of can lids with alcohol swabs before use, rinsing and air drying of intermittent feeding containers between feedings, and limiting feeding container fills to 4-hour hang time quantities. At both institutions, the value of an ongoing three-class enteral quality control program with a defined acceptance/rejection criteria was demonstrated in that ENS contamination was reduced to acceptable levels comparable with federal standards for milk and dairy products.

Enteral Nutrition↗
PubMed1991

Effects of mercury, selenium, and organochlorine contaminants on reproduction of Forster's terns and black skimmers nesting in a contaminated Texas Bay.

Mean mercury (0.40 micrograms/g), and geometric mean DDE (1.6 micrograms/g) and polychlorinated biphenyl (PCB) (2.3 micrograms/g) concentrations in Forster's tern (Sterna forsteri) eggs from Lavaca Bay were higher than those in tern eggs from a reference area in San Antonio Bay, but residues were not correlated with hatching success. Nest success was similar between bays. Selenium levels in Lavaca Bay tern eggs (0.71 micrograms/g) were also comparable to those in eggs from the reference area (0.68 micrograms/g). Clutch size (3.1 to 3.4) of Lavaca Bay black skimmers (Rynchops niger) was no different than that (3.4) at a reference colony near Laguna Vista. Nest success was similar among three Lavaca Bay colonies, but success was lower at one Lavaca Bay colony (40%) than at Laguna Vista (65%). Mean mercury (0.46 micrograms/g) and selenium (0.75 micrograms/g) concentrations in skimmer eggs from Lavaca Bay were higher than those (0.19, 0.33 micrograms/g) from Laguna Vista; however, concentrations of neither contaminant were related to hatching success. DDE concentrations in Lavaca Bay skimmer eggs (3.4 micrograms/g) were similar to those from Laguna Vista (3.2 micrograms/g) and DDE was negatively correlated with hatching success. PCBs were higher in eggs from Lavaca Bay (1.3 micrograms/g) than Laguna Vista (0.8 micrograms/g). Organochlorine and metal contaminants in most eggs were below embryotoxic levels. Eggshell thinning in Forster's terns (7%) and black skimmers (5%) was below that associated with lowered reproduction. DDE and PCBs were detected in 9 Caspian tern (S. caspia) eggs; maximum concentrations were 4.7 and 5.4 micrograms/g. Caspian tern and least tern (S. albifrons) eggs contained low (less than or equal to 0.9 micrograms/g) concentrations of mercury and selenium.

Animals↗
PubMed2026

Leveraging environmental applications and risks of coal gangue: A critical review on authigenic inorganic heavy metals, organic contaminants, and the removal of exogenetic contaminants.

Coal gangue (CG) as bulk solid waste has seriously threatened the ecosystem. Therefore, identifying the key risk drivers and exploring feasible disposal methods for CG are essential for developing a sustainable strategy. However, there is currently a lack of comprehensive information that balances the contamination risks with the valuable constituents present in CG, which hinders its full potential for sustainable use without negative environmental impacts. Given the complex composition and associated risks, we propose that addressing the critical properties related to contamination is crucial for the efficient utilization of CG. On this premise, we summarized several practical resource pathways (ecological multifunctional materials, extraction of rare elements, and soil additives) that are more favorable for sustainable development relative to conventional disposals. Meanwhile, we also propose that coupling disposals could intensely reduce CG's environmental footprints and capital costs. Consequently, regardless of the number of challenges to be solved, we believe the CG has broad application prospects, and we hope this review will promote the conversion of CG into an asset with lower ecological and social impacts.

Metals, Heavy↗
PubMed1971

Prevention of airborne contamination and cross-contamination in germ-free mice by laminar flow.

The efficacy of horizontal and vertical laminar flow units (equipped with high-efficiency air filters) in the prevention of cross-contamination between cages and of contamination from outside has been demonstrated. With germ-free mice and using germ-free standard techniques for sterilization and for the transfer of germ-free mice into the cabinets via a standard entry lock, it was found that during an observation period of 2 weeks the animals remain ;negative'. Other experiments were performed with equally good results in cabinets equipped with a hinged flap, closing 95% of the open front side. When the flap was closed the air flow could be reduced accordingly, thus reducing the noise level and the risk of dehydration.Experiments made with germ-free mice in a ;down-flow unit' were also invariably good.In another type of experiment, cages with conventional mice were placed in the cabinets between cages with germ-free animals at varying distances. If all animals were maintained on wire mesh (to minimize the aerosol production of dust) and if the ;conventional' cages were at a distance of 10 cm. from ;germ-free cages' the latter remained bacteria-free during test periods of one week.The use of ;laminar flow isolators' for the isolation of human patients is mentioned.

Air↗
PubMed1978

Bacterial contamination in a modern operating suite, 2. Effect of a zoning system on contamination of floors and other surfaces.

In this investigation the bacterial contamination of surfaces such as walls and floors in a modern operating suite, together with surfaces of lamps in the operating theatres, and the clogs worn by staff, was studied. Counts of colony-forming units were made on impression plates containing blood-agar with Tween 80 for total bacterial counts, Baird Parker medium with egg yolk and tellurite for Staphylococcus aureus and trypticase peptone agar with neomycin and polymyxin for Clostridium spp. The areas examined were divided into the patients' route to the operating theatre, the staff's route, and the central area containing the operating rooms, anaesthetic rooms, and exit and scrub-up areas. In the patients' route counts of total organisms ranged from about 10000 to 30000/m2; for Staph. aureus the range was from 70 to 540/m2. In the staff's route the highest count was about 70000/m2 in the dressing area, and the numbers of Staph. aureus were about the same as along the patients' route. In the inner zone the counts were somewhat lower for both total organisms and Staph. aureus. Total counts on the floor from all areas of the inner zone were significantly higher just before the second operation than before the first operation on the same day. The total and Staph. aureus counts on walls, floors and lamps were the same after clean operations as after operations classified as "contaminated" or "dirty".

Air Microbiology↗
PubMed1992

Efficiency of measures aimed at decreasing the contamination of agricultural products in areas contaminated by the Chernobyl NPP accident.

The sequence of agricultural countermeasures taken in the Polessye area of the Ukraine contaminated by radionuclides as a result of the Chernobyl NPP accident is discussed. The efficiency of these countermeasures has been analysed. The concentration of 137Cs in crops has been shown to vary 10-100-fold, depending on the biological features of the plant species and on soil properties. Liming and mineral fertilizing of meadows increase the yield of grass and reduce 137Cs transfer to cows' milk up to 3.5-fold.

Accidents↗
PubMed1979

Accidental contamination of diagnostic cultures of mycobacteria and phage identification of the contaminating strain.

Phage typing of mycobacteria is a new technique not yet widely used for classification and intraspecies differentiation. Systematic long-term studies organized by the WHO have succeeded, using a battery of 11 different mycobacterial phages, in dividing M. tuberculosis into 3 different phage sub-groups, preliminarily labelled as A, B and C. A special case of phage-typing is presented which enabled identification of a virulent mycobacterial strain causing accidental contamination of diagnostic mycobacterial cultures. The strain was an old laboratory one, H37Rv, belonging to phage subgroup B.

Bacteriophage Typing↗
PubMed1978

Bacterial contamination in a modern operating suite. 3. Importance of floor contamination as a source of airborne bacteria.

The redispersal factor for bacteria-carrying particles from a contaminated floor was determined after mopping, blowing and walking activity. Walking gave the highest redispersal factor, 3.5 X 10(-3) m-1, which was three times higher than for blowing and 17 times higher than for mopping. The mean die-away rate for the bacteria-carrying particles used was 1.9/h without ventilation and 14.3/h with ventilation. It was calculated that in the operating rooms less than 15% of the bacteria found in the air were redispersed floor bacteria.

Air Microbiology↗
PubMed1988

Contaminating coagulase-negative staphylococci isolated in a lysis-centrifugation (Isolator) blood culture system. Application of different epidemiological markers for deduction of mode of contamination.

The lysis-centrifugation blood culture system, Isolator, is a promising system with respect to detection of many significant microorganisms, e.g. Staphylococcus aureus and Enterobacteriaceae, as compared with conventional systems. A drawback of the Isolator system is a disturbingly high rate of clinically insignificant, supposedly contaminating coagulase-negative staphylococci, which leads to considerable waste of time and materials in the laboratory. Several sources of these isolates have been proposed (viz. the patient, the ward environment, the laboratory handling, and the plate media). The aim of this study was to pinpoint the origin of these clinically doubtful coagulase-negative staphylococci, using different epidemiological markers, such as species identification, antibiotic susceptibility patterns, phage-types, and plasmid profiles. Plasmid profile analysis proved to be more discriminating than the other techniques and made it possible to conclude that the laboratory handling of the Isolator system was a major source of coagulase-negative staphylococci in this system.

Bacteriological Techniques↗