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At least 163 records · Page 9Linked to original sources

PubMed1987

Microbial contamination associated with routine aseptic practice.

We have studied the rate of fortuitous contamination associated with routine aseptic technique under operational conditions. Stainless steel strips, as simulators of surgical instruments, were contained in sterilized surgical packs and assayed by nursing personnel during surgical and other invasive procedures at three different hospitals. The rates of contamination observed for the 36 investigators ranged from 0% to 11.3%, with an overall rate of 2.7%. Assays conducted in a clean room environment, under conditions approaching industrial sterility standards, showed a contamination rate of 0.16%. We concluded that aseptic practices, as routinely performed without any noticeable breaks or transgressions, do not guarantee sterility. The concept of surgical sterility implies low level, but measurable, microbial contamination.

Antisepsis↗

PubMed1995

The experimental study of microbial contamination of the space hardware.

The role of potential contaminants of design materials and products of space technology--aerobic and anaerobic prokaryotes (myxobacteria, eubacteria, corinebacteria, actinomyces), and eukaryotes (micromyces), psychrophilic, mesophilic and thermophilic forms, chemolythotrophic microorganisms is discussed in this paper. The methods of analysis of microbial contamination in the solution of problem of the planetary protection are considered. The necessity of the use of ultrasound at the evaluation of surface and subsurface contamination of specimens is demonstrated; methods of determination of buried contamination (with the use of organic solvents and mechanical pulverization) are discussed. The data on buried and subsurface contamination for some materials and electronic parts together with microflora resistivity to sterilizing treatment are given.

Bacteria↗

PubMed2003

Microbial contamination of two urban sandstone aquifers in the UK.

Development of urban groundwater has historically been constrained by concerns about its quality. Rising urban water tables and overabstraction from rural aquifers in the UK have led to a renewed interest in urban groundwater, particularly the possibility of finding water of acceptable quality at depth. This study assessed the microbial quality of groundwater collected from depth-specific intervals over a 15-month period within the Permo-Triassic Sherwood Sandstone aquifers underlying the cities of Nottingham and Birmingham. Sewage-derived bacteria (thermotolerant coliforms, faecal streptococci and sulphite-reducing clostridia) and viruses (enteroviruses, Norwalk-like viruses, coliphage) were regularly detected to depths of 60 m in the unconfined sandstone and to a depth of 91 m in the confined sandstone. Microbial concentrations varied temporally and spatially but increased frequency of contamination with depth coincided with geological heterogeneities such as fissures and mudstone bands. Significantly, detection of Norwalk-like viruses and Coxsackievirus B4 in groundwater corresponded with seasonal variations in virus discharge to the sewer system. The observation of low levels of sewage-derived microbial contaminants at depth in the Triassic Sandstone aquifer is explained by the movement of infinitesimal proportions of bulk (macroscopic) groundwater flow along preferential pathways (e.g., fissures, bedding planes). The existence of very high microbial populations at source (raw sewage) and their extremely low detection limits at the receptor (multilevel piezometer) enable these statistically extreme (microscopic) flows to be traced. Rapid penetration of microbial contaminants into sandstone aquifers, not previously reported, highlights the vulnerability of sandstone aquifers to microbial contamination.

Cities↗

PubMed1967

Use of ultrasonic energy in assessing microbial contamination on surfaces.

Ultrasonic tanks were evaluated for their ability to remove viable microorganisms from various surfaces for subsequent enumeration. Test surfaces were polished stainless steel, smooth glass, frosted glass, and electronic components. The position of contaminated surfaces in relation to the ultrasonic energy source, distance of the ultrasonic source from the test surfaces, and temperature of the rinse fluid were some of the factors which influenced recovery. Experimental systems included both naturally occurring microbial contamination and artificial contamination with spores of Bacillus subtilis var. niger. The results showed that ultrasonic energy was more reliable and efficient than mechanical agitation for recovering surface contaminants. Conditions which increased the number and percentage of microorganisms recovered by ultrasonic energy were: using a cold rinse fluid, placing the sample bottle on the bottom of the ultrasonic tank, and facing the contaminated surfaces toward the energy source. It was also demonstrated that ultrasonic energy could be effectively used for eluting microorganisms from cotton swabs.

Journal Article↗

PubMedDate not supplied

Low-cost screening for microbial contaminants in aerosols generated in a dental office.

It has been reported that aerosols and droplets generated by high-speed dental drills and cavitrons are contaminated with blood and bacteria and represent a potential route for transmitting disease. Bacterial cells possess a negative electrical charge, while the cathode ray tubes (CRT) that are used in computer monitors generate positively charged static electric fields. Consequently, bacteria dispersed within these aerosols could be attracted to the screens on CRT monitors. In this study, pathogenic strains of Staphylococcus aureus were found on CRT screens in different locations within the Louisiana State University School of Dentistry facility. The results suggest that surveying CRT screens is a simple method for evaluating the airborne microbial contaminants present within a dental office.

Aerosols↗

PubMed1993

Microbial contaminants found in low egg passage rabies vaccine used in Nigeria.

Bacteriological and mycological examinations (cultural and biochemical characteristics) identified 4 pathogenic organisms as contaminants in 6 out of 7 LEP batch 20 rabies vaccines produced 1990 in Nigeria. Cryptococcus neoformans and Penicillium spp. were isolated from 5 vaccine samples, while one sample additionally also contained Rhizopus and Pseudomonas. One vaccine sample was negative for microbial contaminants. Improper conditions of vaccine production and storage are discussed.

Animals↗

PubMed2004

Development of a toolbox to assess microbial contamination risks in small water systems.

Individual and small water systems account for the majority of waterborne disease outbreaks recorded in the United States each year. To address this problem a project was undertaken to develop a comprehensive self-assessment toolbox that could be used by small water system personnel to determine where their system has the greatest potential risks from microbial contamination. The toolbox components consist of: (1) a survey that asks specific questions; (2) a ranking tool that computes numerical scores for water system components based on survey answers; (3) comments and results from the ranking tool; (4) a guidance document to help the user understand why certain conditions may represent a risk; and (5) instructions for using the toolbox. A unique feature of the ranking tool is the ability to input expert opinion in the form of scores for each answer and weighting factors. Weighting factors are derived using ranked, pairwise comparisons, and then used to determine numerical scores for system components. Toolbox administrators are allowed to modify weighting factors used by the ranking tool application, thus allowing input of expert opinion.

Disease Outbreaks↗

PubMed2004

Control of microbial contamination during surgical harvest of pig renal xenografts.

The pig has been identified as the most likely source of xenograft material for clinical use and studies are ongoing to overcome the immunological hurdles of pig-to-human transplantation. Attention is now being focussed on identifying and reducing the potential microbiological hazards associated with this technique. Studies have primarily addressed issues surrounding the production and health monitoring of xenograft source pigs and none have so far specifically evaluated the possible risks of microbial contamination during xenograft harvest. In this report, we evaluate the possible routes for contamination of a pig kidney xenograft during organ harvest and describe approaches to the control of these hazards, including the novel use of a custom designed airtight surgical canopy. A standard procedure for microbiological monitoring during xenograft harvest was devised and evaluated. This allowed the rapid identification and anti-microbial sensitivity testing of any isolated organisms. This would enable an early and appropriate pre-emptive treatment of infection because of transmission of pig micro-organisms.

Animals↗

PubMed2004

Efficacy of A-dec's ICX dental unit waterline treatment solution in the prevention and treatment of microbial contamination in dental units.

OBJECTIVE: Even though some chemical agents can disinfect biofilms in dental unit waterlines, there remains concern that all remnants of the biofilm matrix are not eliminated. Even with periodic treatments, the bacterial populations in dental unit waterlines recur rapidly. In addition, with some previously tested products, patient safety, as well as toxic, caustic and corrosive residual chemicals are also a concern. This study evaluated ICX, A-dec's new water treatment solution, in a series of experiments for prevention, microbial spectrum of activity, minimum inhibitory time determination, and treatment of established biofilms. METHODOLOGY: New dental unit waterline tubing was treated continuously during simulated patient care over 28 days with municipal water. It was then treated with ICX. Effluents from lines with established biofilms (averaging > 10(4) CFU/ml at day 0) were treated to assess levels of CFU counts within 21 days of exposure to ICX. RESULTS: Tubing treated with ICX did not develop a detectable biofilm using ruthenium red staining, and microbes in effluents remained undetectable. CONCLUSION: ICX is effective in maintaining the effluent within the American Dental Association's and the Centers for Disease Control's recommendation for < 500 CFU/ml. In addition, considering the preliminary finding that ICX reduces microbial contamination of effluents from established biofilm lines, it may be useful in long-term treatment alone or when coupled with a shock treatment to assist in biofilm destruction.

Biofilms↗

PubMed1992

Microbial contamination of hydrophilic contact lenses. Part II: Quantitation of microbes after patient handling and after aseptic removal from the eye.

We cultured Soflens (polymacon) contact lenses to determine the number of microorganisms present after patient handling and the number present after patient handling and 5 hours of lens wear. Twenty adapted contact lens patients were each dispensed two pairs of new sterile Soflens contact lenses. Both pairs of lenses were handled by the patients during a single experimental session. Prior to handling lenses, patients were instructed to wash their hands with soap and water, rinse with tap water, and dry with a paper towel. One pair (handled-only) was cultured immediately after handling. The second pair (handled-and-worn) was placed on the eyes by the patient, removed aseptically following 5 hours of wear, and then cultured. All 40 handled-only lenses had viable microorganisms associated with them (mean: 653 colony forming units (CFU) per lens). Bacteria were isolated on all of these lenses and fungi were detected on six. The mean bacterial count for the handled-and-worn lenses was 30 CFU/lens; fewer than half exhibited handled-and-worn lenses was 30 CFU/lens; fewer than half exhibited bacteria and no fungi were isolated. These data suggest that patient handling is a highly significant source of microbial contamination of hydrophilic contact lenses. Also, the number of microorganisms on lenses is significantly reduced (P < 0.0001) after the lens has been worn on the eye.

Asepsis↗

PubMed1977

[Sources of microbial contamination in the production of veal].

Investigated was the microflora of various objects contributing to the contamination of veal during the process of its production. It was found that the main sources of primary contamination of the carcass surface with microorganisms are the hair coat, residual mud on the hoofs, intestinal contents of the calves for slaughter, the slaughter premise itself (walls, floor, air), tools used in slaughter (knives, axes for cutting open), clothing for work as well as the hands of the workers. The microbial contamination of the objects studied during work proved strong, in some cases the log value of the total count of organisms for some of them reaching up to 8.90, of the psychrophiles--up to 7.91, of the coliform bacteria--up to 7.04, of the moulds and yeasts--up to 6.08. Disinfection with 1 per cent water solution of Vosfasteril lowered the contamination of the objects studied by more than 99 per cent. The detergent used produced a high bactericidal effect and could successfully be employed at the meat producing enterprises throughout the country.

Animals↗

PubMed1984

A comparison of methods for the estimation of the proportion of microbial nitrogen in duodenal digesta, and of correction for microbial contamination in nylon bags incubated in the rumen of sheep.

Four sheep, each fitted with cannulas in the rumen and proximal duodenum, were given two diets (1390 g dry matter (DM)/d) consisting of lucerne (Medicago sativa) pellets (24.2 g nitrogen/kg DM) plus pelleted reed canary grass (Phalaris arundinacea; 14.1 g N/kg DM) or chopped hay (11.8 g N/kg DM) at intervals of 2 h. Flow of duodenal digesta measured by reference to the markers 51Cr-EDTA and 103Ru-phenanthroline indicated a net gain of 5.8-7.5 g non-ammonia-N (NAN) between mouth and duodenum. The proportion of microbial N in duodenal digesta N was estimated using 15N and 35S incorporation into bacteria and digesta. Two methods of analysis for 35S content, the Bird & Fountain (1970; B&F method) and the Mathers & Miller (1980; M&M method), were used. (15NH4)2SO4 and Na2(35)SO4 were infused into the rumen for 3.5 d before and 4.0 d during sampling. A bacterial fraction was prepared from the fluid phases of sampled duodenal digesta and rumen contents by differential centrifugation. In addition, samples of ground canary grass and of lucerne were incubated in nylon bags in the rumen for 3-48 h during the infusion. Each of the 35S analytical methods yielded similar values of 35S content of isolated rumen or duodenal bacteria, but there was more (P less than 0.05) incorporation of 15N into rumen than into duodenal bacteria. Relative to values obtained using the M&M method and 15N incorporation, the B&F method for S analysis yielded higher (P less than 0.05) estimates of microbial content of duodenal digesta from sheep given chopped reed canary grass. 35S activity associated with washed nylon-bag residues increased rapidly with time-period of incubation and was substantially greater (P less than 0.05) when analysed by the B&F method compared with the M&M method. The 35S content (/g DM) of adherent bacteria removed from nylon-bag residues by homogenization in a second experiment varied from 0.65 to 1.88 that of free-living bacteria isolated from rumen fluid by differential centrifugation. The difference in 35S content in digesta and nylon-bag residues as measured using the two analytical methods was considered in relation to 35S-labelled extracellular material postulated to be produced by bacteria adherent to plant residues. Estimates of disappearance of dietary N from nylon bags after correction for microbial contamination indicated a disparity with estimates based on in vivo information.

Animal Feed↗

PubMed1974

Factors that influence microbial contamination of fluids associated with hemodialysis machines.

Studies were conducted on the microbiological quality of fluids associated with different types of dialysis systems located in six dialysis centers and 14 homes. Included were (i) single-pass systems employing either parallel flow (Kiil or Gambro) or capillary cartridge dialyzers and (ii) recirculating single-pass and batch recirculating systems using coil dialyzers. Microbiological assays were performed on the water used to prepare dialysis fluid, the concentrated dialysate, and either pre- and postdialyzer dialysate (single-pass systems) or the dialysate contained in storage reservoirs and recirculating cannisters (recirculating systems). The levels of microbial contamination consisting of gram-negative bacteria were directly related to the type of dialysis system, method of water treatment, distribution system, and in some instances, the type of dialyzer. Recirculating single-pass and batch recirculating systems consistently contained significantly higher levels of contamination than single-pass systems. These results were directly related to the design of recirculating systems which permits carbon- and nitrogen-containing waste products dialyzed from the patient to accumulate, be used as nutrients by microorganisms, and subsequently allow for 2- to 4-log increases in contamination levels during a dialysis treatment. In contrast, levels of contamination in single-pass machines were related more to the quality of the water used to prepare dialysis fluid and the adequacy of cleaning and disinfection procedures than to the design of the system.

Acinetobacter↗

PubMed2004

Risk analysis of drinking water microbial contamination versus disinfection by-products (DBPs).

Managing the provision of safe drinking water has a renewed focus in light of the new World Health Organization (WHO) water safety plans. Risk analysis is a necessary component to assist in selecting priority hazards and identifying hazardous scenarios, be they qualitative to quantitative assessments. For any approach, acute diarrhoeal pathogens are often the higher risk issue for municipal water supplies, no matter how health burden is assessed. Furthermore, potential sequellae (myocarditis, diabetes, reactive arthritis and cancers) only further increase the potential health burden of pathogens; despite the enormous uncertainties in determining pathogen exposures and chemical dose-responses within respective microbial and chemical analyses. These interpretations are currently being improved by Bayesian and bootstrapping approaches to estimate parameters for stochastic assessments. A case example, covering the health benefits of ozonation for Cryptosporidium inactivation versus potential cancers from bromate exposures, illustrated the higher risks from a pathogen than one of the most likely disinfection by-products (DBPs). Such analyses help justify the industries long-held view of the benefits of multiple barriers to hazards and that microbial contamination of water supplies pose a clear public health risk when treatment is inadequate. Therefore, efforts to reduce potential health risks from DBP must not compromise pathogen control, despite socio-political issues.

Carcinogens↗

PubMed2005

Microbial contamination of cell cultures: a 2 years study.

Cell line contamination is a major drawback of main cell banks of the world and it has cost of losing important biological products or valuable research. The causative agents are different chemicals, invertebrates, bacteria, fungi, parasites, viral species and even other cell lines. In this retrospective study, cell lines from various species such as human, fish, insect, animals either offered or accessed through usual official accession in CGBRI were studied during 2 years (2002-2004) to detect their microbial contaminations and the causative organisms. Samples were taken for sterility test upon cell lines receipt and upon each cell line sub-culture. Samples were examined for bacterial (including mycoplasmas) and fungal contamination using conventional microbiological techniques. The study excluded parasites, viruses and other contaminating agents. This study revealed 39% of specimens were contaminated. The major contaminating agents were mycoplasmas (19%) followed by mixed infection (8%), fungi (8%) and bacteria (4%). Among various bacterial species (except mycoplasmas) Bacillus sp., Enterococcus sp. and Staphylococcus sp. are main bacterial agents and among various fungi Aspergillus sp. followed by Penicillium sp., Sepedonium sp. and Botrytis sp. were main fungal causative agents of CGBRI cell line contamination. Our study also delineates each cell line contamination rate and its causative agents. This is the first report of cell culture contamination from cell banks of Middle-East countries like Iran.

Animals↗

PubMedDate not supplied

Potential for microbial contamination of ADD-Vantage admixtures.

OBJECTIVE: To test for potential bacterial contamination of the ADD-Vantage system when the components are assembled in various hospital environments. STUDY DESIGN: One hundred fifty ADD-Vantage units were assembled by three different people in three separate locations within a hospital. Each person assembled ten units per day; the study spanned five days. After 72 hours of incubation, units were inspected for evidence of contamination. SETTING: ADD-Vantage units were assembled by a pharmacist in a laminar-flow hood, a pharmacy student using the pharmacy counter, and a nurse at a patient's bedside table. Personnel at each site wore their regular work attire. Each person observed handwashing techniques normally used during routine working hours. DATA EXTRACTION: Positive results were sent to the hospital microbiology laboratory for determination of growth type. RESULTS: After 72 hours, none of the systems exhibited microbial growth on visual inspection. No differences in microbial contamination of the ADD-Vantage systems relative to assembly site, day of assembly, or person performing the assembly were observed. The incidence of contamination was calculated at less than seven percent. CONCLUSIONS: There is minimal risk of bacterial contamination when ADD-Vantage systems are compounded either on a pharmacy counter or at a patient's bedside. Larger samples must be studied in order to detect differences in the incidence of contamination among assembly sites.

Cimetidine↗

PubMedDate not supplied

[Total parenteral nutrition: a study of the microbial contamination of the bags and the infusion lines].

The authors have examined during 60 groups of patients submitted to TPN each for a period of 10-15 days. In the first group the whole infusional set became replaced after 24 h., in the second and in the third group such replacement was done, respectively, after 48 and 72 h. The bacteriological examination of the fluid in the was always sterile 6 h. after preparation except in one case of the third group. The bacteriological examination of the terminal part of the infusional set was always negative in the first group, it was positive in the 3.33% of the cases, in the second group and in the 6.66% of the cases in the third group. The authors, consequently, believe that the infusional set has to be replaced after a period no longer than 24 h. Total parenteral nutrition: study on microbial contamination of bags and infusion lines.

Asepsis↗

PubMed1996

Microbial contamination in an in vitro fertilization-embryo transfer system.

OBJECTIVE: To determine sources and transmission of microorganisms in IVF-ET and efficacy of in-place controlling systems. DESIGN: Prospective study. SETTING: In Vitro Fertilization-Embryo Transfer Unit at a university teaching hospital. PATIENTS: Twenty-eight couples undergoing 30 completed IVF-ET cycles. INTERVENTIONS: Gamete and embryo processing in a penicillin and streptomycin-rich medium. MAIN OUTCOME MEASURES: Presence of microorganisms at various stages of IVF-ET. Fertilization, cleavage, and pregnancy rates. RESULTS: In 50% of cycles no microorganisms were isolated and in the other 50% microbes were cultured from various loci. Cultures of four preprocessed semen samples were positive and corresponding postprocessed samples negative. Microbes were detected in 27% of needle washes after oocyte collection; in 40% and 32% of follicular fluids from left and right ovaries, respectively; and in two culture media from egg-sperm incubations at 20 hours after insemination. No microorganisms were grown from media from zygote incubations. Fertilization, cleavage, and pregnancy rates were independent of microbial presence. CONCLUSION: Seminal fluid and transvaginally collected oocytes are potential sources of microbial contamination of the IVF-ET culture system. A penicillin- and streptomycin-rich culture medium is effective in removing contaminating microbes. End point measures are not affected by commensal contamination.

Culture Media↗