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PubMed2006

Risk factors for infection of the diabetic foot with multi-antibiotic resistant microorganisms.

AIM: To investigate the risk factors for infection of the diabetic foot with multidrug resistant microorganisms. METHODS: Amongst 102 diabetic patients with evidence of soft tissue infection of the foot who presented to our health center over a three year period, we investigated risk factors that might be predictive of multi-antibiotic resistance of the infecting organism. RESULTS: Of 102 patients with a diabetic foot wound, bacteria were cultured from 73, yielding a total of 104 isolates. The number of multidrug resistant isolates was 42 from 36 cases and the number of isolates other than multidrug resistant ones was 62 from 37 cases. Previous antibiotic therapy (p=0.002) and its duration (p=0.0001), frequency of hospitalization for the same wound (p=0.000), duration of hospital stay (p=0.000) and osteomyelitis (p=0.001) were significant risk factors for infections with multidrug resistant microorganisms. CONCLUSION: In conclusion, an appropriate antibiotic should be initiated promptly, wound perfusion should be effective, duration of hospital stay should be as short as possible and optimum hygiene should be provided during wound care to prevent infections of diabetic foot wound with multidrug resistant microorganisms.

Aged↗
PubMed2004

A simple method for differential isolation of freely dispersed and particle-associated peat microorganisms.

Differential isolation of physiologically and ecologically diverse microbial groups facilitates evaluation of their activities in the environment. Here we describe a new method for differential isolation of freely dispersed and particle-associated peat microorganisms. The method is based on sequential elution of peat. Two types of natural peat, "young" sphagnum peat and "old" reed-based peat that have significantly different molecular composition as revealed by solid-state 13C NMR, were used for the method development. Various combinations of elution parameters (pH values, surfactant concentration, and sonication) were tested. Protein yield, CFU counts, 16S rDNA gene sequence, and T-RFLP analyses were used as criteria for evaluating the effectiveness of the elution protocols. The optimal method consisted of sequential elutions with (i) pH 6.2, 0.1 M potassium phosphate buffer, (ii) the same buffer amended with 0.01% of Tween 80, and (iii) treatment (ii) amended with sonication for 2 min. This method allowed differential isolation of freely dispersed and particle-associated microorganisms with (i) highest yield, (ii) highest diversity within the each microbial fraction, and (iii) best discrimination between the freely dispersed and particle-associated microbial communities. The method was applied for characterization of peat microbial communities and revealed different taxonomic composition and similar spatial organization of sphagnum and reed-sage peat microorganisms.

Arthrobacter↗
PubMed2006

Food-processing enzymes from recombinant microorganisms--a review.

Enzymes are commonly used in food processing and in the production of food ingredients. Enzymes traditionally isolated from culturable microorganisms, plants, and mammalian tissues are often not well-adapted to the conditions used in modern food production methods. The use of recombinant DNA technology has made it possible to manufacture novel enzymes suitable for specific food-processing conditions. Such enzymes may be discovered by screening microorganisms sampled from diverse environments or developed by modification of known enzymes using modern methods of protein engineering or molecular evolution. As a result, several important food-processing enzymes such as amylases and lipases with properties tailored to particular food applications have become available. Another important achievement is improvement of microbial production strains. For example, several microbial strains recently developed for enzyme production have been engineered to increase enzyme yield by deleting native genes encoding extracellular proteases. Moreover, certain fungal production strains have been modified to reduce or eliminate their potential for production of toxic secondary metabolites. In this article, we discuss the safety of microorganisms used as hosts for enzyme-encoding genes, the construction of recombinant production strains, and methods of improving enzyme properties. We also briefly describe the manufacture and safety assessment of enzyme preparations and summarize options for submitting information on enzyme preparations to the US Food and Drug Administration.

Animals↗
PubMed1996

Role of bacterial vaginosis-associated microorganisms in endometritis.

OBJECTIVE: Our goal was to define the role of bacterial vaginosis and bacterial vaginosis-associated microorganisms in endometritis. STUDY DESIGN: Endometrial biopsies were obtained for histologic and microbiologic study from 178 consecutive women with suspected pelvic inflammatory disease, and 85 of them underwent laparoscopy to diagnose salpingitis. RESULTS: Histologic endometritis was confirmed in 117 (65%) of the women. Among women who underwent laparoscopy, salpingitis was present in 68% of those with and 23% of those without endometritis. Some but not all bacterial vaginosis-associated microorganisms were linked with endometritis. By logistic regression analysis, after adjustment for bacterial vaginosis and isolation of Neisseria gonorrhoeae and Chlamydia trachomatis, endometritis was associated with endometrial N. gonorrhoeae (odds ratio 5.7, 95% confidence interval 1.8 to 17.5), C. trachomatis (odds ratio 4.8, 95% confidence interval 1.3 to 18.2), anaerobic gram-negative rods (odds ratio 2.6, 95% confidence interval 1.1 to 5.7), and nonwhite race (odds ratio 2.3, 95% confidence interval 1.1 to 4.8). CONCLUSIONS: The association of anaerobic gram-negative rods with endometritis, after adjustment for bacterial vaginosis, N. gonorrhoeae, and C. trachomatis, supports the role of these microorganisms in the etiology of histologic endometritis among women with clinically suspected pelvic inflammatory disease.

Adult↗
PubMed1971

Spectral analysis of laser light scattered from motile microorganisms.

The theoretical basis of laser scattering from motile microorganisms is examined. Spectra of swimming particles are compared with spectra arising from brownian motion. For mixtures of motile and resting organisms, that part of the spectrum related to the motile organisms is enhanced when V(s)/|k|D is large, where V(s) is the mean swimming speed of the motile microorganisms,|k| is the Bragg wave vector, and D is the diffusion coefficient of the nonmotile particles. When the directed motion of swimming microorganisms persists for periods which are much longer than tau = (|k|V(s))(-1), the scattering spectrum is given as S(k, omega) infinity P(| [omega - omega(0)]/k|), where P is the probability distribution obtained by two-dimensional integration over the swimming speed distribution. A computation of scattering from bull spermatozoa, based on published velocity distributions, is investigated in detail.

Animals↗
PubMed2000

Are seminal fluid microorganisms of significance or merely contaminants?

OBJECTIVE: To determine the contribution of urethral and skin flora to seminal fluid cultures and the relation between bacteriospermia and seminal leukocytes. DESIGN: Prospective study. SETTING: IVF-ET unit at a university teaching hospital. PATIENT(S): Sixty men starting an IVF-ET program. INTERVENTION(S): Culture of sequential first-catch urine, midstream urine, and semen samples with evaluation of seminal leukocytes. MAIN OUTCOME MEASURE(S): A comparison of microbes from first-catch urine, midstream urine, and semen samples and the correlations of seminal microbes, elevated leukocyte concentrations, and pregnancy. RESULT(S): Microorganisms were detected in 37% of first-catch urine samples, 27% of midstream urine samples, and 51% of semen samples. Most microorganisms were gram-positive microbes and were common to both urine and semen samples. Mean and median leukocyte concentrations were 0.98 x 10(6)/mL and 0.10 x 10(6)/mL, respectively. There was no correlation between seminal microbes and raised leukocytes or between leukocytospermia and/or bacteriospermia and pregnancy. CONCLUSION(S): Microorganisms are commonly found in insignificant quantities in the semen of asymptomatic men. The frequent isolation of gram-positive microbes common to both urine and semen and the absence of a correlation with raised leukocyte concentrations suggest that bacteriospermia most commonly represents contamination.

Embryo Transfer↗
PubMed2002

Cadmium biosorption by free and immobilised microorganisms cultivated in a liquid soil extract medium: effects of Cd, pH and techniques of culture.

Instead of soil clean-up, a process not very technically and economically suited to agricultural soil contaminated by heavy metals (with a low concentration of heavy metals but highly or potentially highly contaminated surfaces), the control of the transfer of cadmium from the soil to the crops may well be a convenient method. We tested the bacterium ZAN-044, the actinomycete R27 and a basidiomycete Fomitopsis pinicola isolated for their ability to biosorb Cd, in order to inoculate agricultural soils afterwards. We then compared the cadmium biosorption by viable microbial cells which were free or immobilised in alginate beads and incubated in a soil extract liquid medium at various pH values (5, 6 and 7) and cadmium concentrations (1 and 10 mg/l). The Cd concentration in the medium had the most important effect on the percentage of Cd biosorbed by the microorganisms, but the culture mode (free or immobilised cells) was not a side effect. In the case of F. pinicola and the actinomycete R27, the percentage of Cd biosorbed by free cells did not decrease when the Cd concentration in the medium increased (6-42% at the lowest Cd concentration to 11-48% at 10 mg Cd/l). On the other hand, with a low Cd concentration (1 mg Cd/l), the percentage of Cd biosorbed by the bacterium ZAN-044 was maximum (69%) at pH 7, while this bacterium did not grow at 10 mg Cd/l and it did not accumulate Cd. For the three micro-organisms tested, relatively low specific biosorptions of Cd were observed, when the microorganisms were cultivated with a soil extract medium ('poor' medium), comparatively to those with a 'rich' medium. Finally, the choice of microorganism for the inoculation of contaminated soils depends on the cadmium level in the medium and on the distribution of the metal between the biomass and the medium.

Actinomycetales↗
PubMed2001

Structural diversity of microorganisms in chemically perturbed soil assessed by molecular and cytochemical approaches.

Until recently, our understanding of microbial community development in soil ecosystems exposed to different inorganic and organic pollutants has been limited to culturable microorganisms because of the techniques available. The discovery that most soil microorganisms are non-culturable but potentially viable and metabolically active accelerated the application of different culture-independent methods for structural diversity assessments of the microbial community. This review examines the results of recent studies on the impact of heavy metals and organic pollutants on the diversity of the microflora obtained with methods based on analyses of signature biomarkers such as nucleic acids and fatty acids. The application of these techniques allowed researchers to pinpoint reduction of microbial diversity in contaminated soil, and significant shifts in the community structure, leading to the dominance of only a few populations (species) and the disappearance of others, some of which were never isolated by conventional methods (e.g. an increase in Acidobacterium or a decrease in terrestrial non-thermophilic Crenarchaeota). Although the new techniques are not free from limitations, they allow the monitoring of the virtual impact of stressors on soil microorganisms and the direction of resuscitation of the microbial community during natural or induced bioremediation, especially when using combined approaches.

Bacteria↗
PubMed1999

Risk analysis of the thermal sterilization process. Analysis of factors affecting the thermal resistance of microorganisms.

A risk analysis was applied to experimental heat resistance data. This analysis is an approach for processing experimental thermobacteriological data in order to study the variability of D and z values of target microorganisms depending on the deviations range of environmental factors, to determine the critical factors and to specify their critical tolerance. This analysis is based on sets of sensitivity functions applied to a specific case of experimental data related to the thermoresistance of Clostridium sporogenes and Bacillus stearothermophilus spores. The effect of the following factors was analyzed: the type of target microorganism; nature of the heating substrate; pH, temperature; type of acid employed and NaCl concentration. The type of target microorganism to be inactivated, the nature of the substrate (reference or real food) and the heating temperature were identified as critical factors, determining about 90% of the alteration of the microbiological risk. The effect of the type of acid used for the acidification of products and the concentration of NaCl can be assumed to be negligible factors for the purposes of engineering calculations. The critical non-uniformity in temperature during thermobacteriological studies was set as 0.5% and the critical tolerances of pH value and NaCl concentration were 5%. These results are related to a specific case study, for that reason their direct generalization is not correct.

Citric Acid↗
PubMed1999

Resistance responses of microorganisms in food environments.

Food borne microorganisms display a broad spectrum of resistance responses to naturally occurring and intentionally added antimicrobial agents. Resistance may be conferred by innate structural features of the bacterial strain such as an impermeable outer membrane or a mechanism for antibiotic-inactivation. Bacteria previously susceptible to an antimicrobial compound can acquire resistance through mutation or through genetic transfer processes such as transformation, transduction, and conjugation. Resistance can also be conferred by biofilm formation on food processing surfaces as an adaptive response to protect colonies from cleaning and sanitation. Resistant pathogens are a global problem, facilitated by international trade of raw and processed foods. Cross resistance between clinical and nonclinical antimicrobials can exist and is of concern. The development of resistant foodborne pathogens has been attributed to increased antibiotic use in hospitals, outpatient facilities, and veterinary applications. Resistant microorganisms can also develop as a result of physical processes used in food preservation, such as acid treatments and irradiation processes. Strategies to effectively counter resistance development include: changing current practices of antibiotic usage, developing new antibiotics, applying hurdle preservation approaches, preventing bacterial adhesion, and utilizing competitive exclusion. This paper presents an overview of problems arising from the development of microbial resistance, and explores possible solutions for detecting and defeating the adaptive changes of microorganisms.

Drug Resistance, Microbial↗
PubMed2003

Evaluation of bacterial aerotaxis for its potential use in detecting the toxicity of chemicals to microorganisms.

Bacterial aerotaxis (the movement of a cell toward oxygen) was evaluated for its potential use in detecting the toxicity of chemicals to microorganisms. The level of toxicity was determined by the concentration of test chemicals resulting in a 50% inhibition of aerotaxis of Pseudomonas aeruginosa PAO1 after 40 min of exposure. The aerotactic responses of P. aeruginosa were measured by using chemotaxis well chambers. Each clear acrylic chamber had a lower and upper well separated by a polycarbonate filter with a uniform pore size of 8.0 microm. To automatically detect bacterial cells that crossed the filter in response to a gradient of oxygen, P. aeruginosa PAO1 was marked with green fluorescent protein (GFP), and the GFP fluorescence intensity in the upper well was continuously monitored by using a fluorescence spectrometer. By using this technique, volatile chlorinated aliphatic compounds, including trichloroethylene (TCE), trichloroethane, and tetrachloroethylene, were found to be inhibitory to bacterial aerotaxis, suggesting their possible toxicity to microorganisms. We also examined more than 20 potential toxicants for their ability to inhibit the aerotaxis of P. aeruginosa. Based on these experimental results, we concluded that bacterial aerotaxis has potential for use as a fast and reliable indicator in assessing the toxicity of chemicals to microorganisms.

Biosensing Techniques↗
PubMed1998

A new application of BCG antibody for rapid screening of various tissue microorganisms.

BACKGROUND: In routine dermatopathology there is growing demand for a simple, fast, cost-effective, and highly sensitive screening tool for the detection of microorganisms. OBJECTIVE: Our purpose was to determine whether immunostaining with polyclonal anti-Mycobacterium bovis (BCG), which is known for its interspecies cross-reactivity, is a suitable screening method for many common microorganisms in dermatopathologic specimens. METHODS: A total of 254 formalin-fixed, paraffin-embedded skin specimens of viral, protozoal, fungal, and bacterial infections were stained with appropriate histochemical stains and with anti-BCG. RESULTS: Anti-BCG labeled bacteria and fungi with high sensitivity and minimal background staining, but did not react with spirochetes, viruses, or protozoa (Leishmania). The quality and sensitivity of anti-BCG staining were superior to conventional histochemical stains. CONCLUSION: Because of its cross-reactivity with many bacteria and fungi as well as its high sensitivity and minimal background staining, the anti-BCG immunostain is a promising screening tool for the detection of the most common bacterial and fungal microorganisms in paraffin-embedded skin specimens.

Antibodies, Bacterial↗
PubMed2000

Influence of polyacrylamide application to soil on movement of microorganisms in runoff water.

Polyacrylamide (PAM) use in irrigation for erosion control has increased water infiltration and reduced soil erosion. This has improved runoff water quality via lower concentrations of nitrogen, phosphorous, and pesticides, and decreased biological oxygen demand. Since non-toxic high molecular weight anionic PAMs removed clay size sediment particles in flowing water, we hypothesized that PAM would effectively remove or immobilize microorganisms in flowing water. In an agricultural field, we determined the efficacy of PAM-treatment of furrow irrigation water to remove several categories of microorganisms in the inflow and runoff. Treatments were: (1) PAM application and a control; (2) three flow rates; (3) two distances from the inflow point; and (4) three times during each irrigation. After water traveled 1 m at 7.5 and 15.5 l min(-1), PAM-treatment reduced total bacterial and microbial biomass and total fungal biomass relative to the control treatment. After water traveled 40 m at 7.5, 15.5, and 22.5 l min(-1), PAM-treatment reduced algae, the numbers active and total bacteria, active and total fungal length, and total bacterial biomass, total fungal and microbial biomass relative to the control treatment. Although specific organisms were not identified or monitored in this study, the results clearly have implications for controlling the spread of soil-borne plant pathogens and other classes of harmful organisms within and among fields via irrigation water and in re-utilized return flows. Beyond furrow-irrigated agriculture, new methods to manage overland transmission of harmful microorganisms could potentially help control transport of pathogens from animal waste in runoff and groundwater.

Journal Article↗
PubMed2001

Population dynamics of transgenic microorganisms in the different microecosystem conditions.

The role of key environmental factors in adaptation of spore-forming and non-spore-forming transgenic microorganisms (TM) have been studied in model ecosystems. Model TM Escherichia coli Z905 (bearing plasmid genes of bacterial luminescence Ap (r) Lux+) has been found to have a higher adaptation potential than TM Bacillus subtilis 2335/105 (bearing genes of human alpha 2-interferon Km (r) Inf+), planned for employment as a living vaccine under varying environmental conditions. Effects of abiotic factors on migration of natural and recombinant plasmids between microorganisms under model ecosystem conditions has been estimated. The transgenic microorganisms with low copy number survived better under introduction conditions in the microcosms studied. This trend has been shown to be independent of the microcosm type and its complexity. Grant numbers: 99-04-96017, 25, 00-07-9011.

Adaptation, Physiological↗
PubMed2003

Survival and alteration of the plasmid-containing microorganism Escherichia coli Z905/pPHL7 introduced into manmade closed aquatic microcosms.

It has been demonstrated that the transgenic microorganism Escherichia coli Z905/pPHL7 (AprLux+) can exist for a long time at an elevated concentration of mineral salts. The microorganism was introduced into microcosms with sterile brackish water (salinity variable from 21 to 22 g l-1) taken from Lake Shira (Khakasia, Russia). The survival of the microorganism was estimated both by measuring the growth of the colonies on solid nutrient media and by the bioluminescence exhibited by the transgenic strain in samples from the microcosms and in the enrichment culture with the added selective factor-ampicillin (50 micrograms/ml). In the enrichment culture, the bioluminescent signal was registered through the 160-day experiment. It has been shown that in the closed microcosms with brackish water the E. coli strain becomes heterogeneous in its ampicillin resistance. The populations of the transgenic strain were mainly represented by isolates able to persist in the medium containing 50 micrograms/ml, but there were also the cells (about 10%) with the threshold of ampicillin resistance not more than 0.05 micrograms/ml. Thus, it was shown that in the microcosms with brackish water and in the absence of the selective factor the transgenic strain survives and retails the recombinant plasmid.

Ampicillin↗
PubMed2003

Growth of microorganisms in propofol and methohexital mixtures.

PURPOSE: The purpose of this study was to evaluate the growth of 4 different microorganisms in propofol, methohexital, and 1:1 and 1:3 mixtures of propofol and methohexital. MATERIALS AND METHODS: The microbial growth of Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli in 1:1 and 3:1 mixtures of methohexital and 2 types of propofol was measured for 48 hours after mixing the solutions. Two of the 4 test solutions were composed of 1% methohexital combined with Diprivan (AstraZeneca Pharmaceuticals, Wilmington, DE), which uses EDTA as a microbial growth inhibitor. The growth of the same 4 microorganisms was also evaluated in 1:1 and 3:1 mixtures of 1% methohexital and a recently introduced generic propofol marketed by Baxter Pharmaceuticals (Deerfield, IL) that uses sodium metabisulfite as a preservative. RESULTS: Combining either Diprivan or generic propofol with methohexital in a 1:1 or 1:3 mixture ratio resulted in a solution that, like methohexital alone, significantly resisted the growth of C albicans, E coli, S aureus, and P aeruginosa for 48 hours. CONCLUSION: The results of our study suggest that 1:1 and 1:3 mixtures of propofol (either Diprivan or generic propofol) and methohexital behave similarly to methohexital alone by resisting growth of the microorganisms studied over the 48-hour time period. If, as has been reported elsewhere, the mixture of these 2 agents results in a solution with desirable anesthetic properties, its ability to resist microbial growth becomes clinically significant by extending the shelf-life of propofol in these mixtures.

Analysis of Variance↗
PubMed1978

Interrelationships between soil microorganisms and polystyrene.

Transmission and scanning electron microscopy along with autoradiographic procedures were used for evaluating the interrelationship between soil microorganisms and polystyrene. Two hypotheses, allowing to explain the properties of polystyrene as a soil conditioner, were investigated: the first is concerned with a possible action of soil microorganisms on the compound; the second, reciprocally, with the polystyrene interference on microorganisms. Radioactivity translocation of 14C-Ecolyte-polystyrene along fungal hyphae and asexual fructification of strains, isolated from soil, as well as cytological modification at the cell wall level of the same microfungi, cultivated in the presence of polystyrene have been ascertained.

Cladosporium↗
PubMed1999

Methods for the differentiation of microorganisms.

Advances in analytical and diagnostic assays based on novel nucleic acid analyses techniques have revolutionized the application of molecular differentiation of microorganisms. Phenotypic typing schemes are now broadly supplemented by new genotyping methods which allow a more refined and detailed differentiation of closely related microorganisms, bacterial strains, isolates and pathogens on the DNA level. Bio-, sero- and phagetyping, antibiotic susceptibility tests, immunoblotting as well as multilocus enzyme- or polyacrylamide gel electrophoresis are now supported by the analysis of plasmid or chromosomal DNA restriction profiles, ribotyping, pulsed-field gel electrophoresis and polymerase- or ligase-chain reaction-based methods or direct sequencing technique to differentiate microorganisms. Some of these molecular techniques are also used in the field of virology to analyse and differentiate closely related sub- or genotypes. Few examples for the analysis and investigation of these usually small genomes will also be given.

Genotype↗