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PL
W artykule omówiono znaczenie bakterii z rodziny Enterobacteriaceae jako ważnej grupy uwzględnianej przy ustalaniu kryteriów higieny procesu produkcji środków spożywczych. Przedstawiono ogólną charakterystykę Enterobacteriaceae, źródła, z jakich dostają się do produktów spożywczych i ich ujemny wpływ na jakość tych produktów. Zwrócono uwagę na wzrastające znaczenie gatunków chorobotwórczych Yersinia enterocolitica i Enterobacter sakazakii.
EN
The article presents the importance of the Enterobacteriaceae family as the important group considered as the hygienic criterion in food production. The general characteristics of Enterobacteriaceae as well as their sources in food products and negative effects on the quality of those products are presented. The increasing importance of pathogenic species Yersinia enterocolitica and Enterobacter sakazakii is mentioned.
EN
Antibiotic resistance of 114 strains of the Enterobacteriaceae family bacteria isolated from vegetables, originating from retail, was investigated in the study. The highest number of the strains isolated were resistant to ampicilin (81.9%), whereas a lower number of the strains exhibited resistance to the following antibiotics: neomycin (29.3%), streptomycin (28.4%), rifampicin (21.5%), chloramphenicol (19.8%), colistin (12.9%), and nitrofurantoin (11.%). All the isolated strains appeared to be susceptible to vancomycin, kanamycin, doxycyclin, nalidixic acid and gentamycin.
PL
Określono oporność na antybiotyki 114 szczepów pałeczek z rodziny Enterobacteriaceae wyizolowanych z warzyw, pochodzących z handlu detalicznego. Wśród wyizolowanych szczepów najwięcej było opornych na ampicylinę 81,9%, natomiast mniej szczepów wykazywało oporność na następujące antybiotyki: neomycynę 29,3%, streptomycynę 28,4%, rifampicynę 21,5%, chloramfenikol 19,8%, kolistynę 12,9%, nitrofurantoinę w 11,2%. Wszystkie wyizolowne szczepy były wrażliwe na wankomycynę, kanamycynę, doksycyklinę, kwas nalidyksowy oraz gentamycynę (tab. 3).
PL
Przedstawiono wyniki badań ilościowych i jakościowych drobnoustrojów z rodziny Enterobacteriaceae w wodzie kąpielisk jeziora Wigry. Próby wody do badań mikrobiologicznych pobierano na terenie 8 najbardziej uczęszczanych kąpielisk jeziora Wigry w odstępach jednomiesięcznych od czerwca do września w latach 1995-1999. Próby wody pobierane ze stanowisk usytuowanych na terenie Ploso Północnego charakteryzowały się wyższą liczebnością drobnoustrojów z rodziny Enterobacteriaceae w porównaniu z próbami wody pobieranymi na pozostałych stanowiskach. Spośród bakterii z rodziny Enterobacteriaceae najliczniej były reprezentowane rodzaje Enterobacter, Escherichia, Citrobacter i Klebsiella. Rzeka Czarna Hańcza, do której dopływają ścieki z oczyszczalni ścieków w Suwałkach, ma istotny wpływ na zanieczyszczenie jeziora Wigry.
EN
Objectives: Public bath waters are used for recreation and bathing purposes, so their sanitary and bacteriological condition is important for the users safety. Because some infections are caused by bacteria from Enterobacteriaceae family, the aim of the study was detection and analysis of occurrence and differentiation of the waterborne bacteria! pathogens from this family in the water of Wigry Lake public bath areas. Wigry Lake is situated in north-eastern Poland, in the area of Wigry National Park. Methods: Eight sampling sites in the most frequently attended public bath areas of the lake, situated near landing stages, camping sites and holiday resorts were investigated. The water samples were collected from June 1995 to September 1999 at one-month intervals, during bathing season. The samples were taken from depth of 0.3 m at each site, poured into 250 ml sterile bottles with water-tight glass closures, transported at 4-^6°C to the laboratory and subjected to bacteriological analyses within 12 hours from collection. Microbial investigations involved the membrane filtration method (with 0.22 urn pore-size filters, Millipore). Volume ranging 1,10 and 50 ml of the sample were filtered through filter and the filters were incubated on solid media Endo Agar in the plates. Another 50 ml of the same water sample was inoculated into 50 ml of Mueller-Kaufmann's medium. Plates and flasks were incubated at 37°C for 24 or 48 hours. The isolates were preliminary screened using the following tests: cytochromeoxidase, Gram stain and motility. Only the strains found to be oxidase and Gram negative were considered to be potential Enterobacteriaceae. Individual colonies from each plate were then picked up, tested for activity and inoculation on solid media Chromocult Agar, Rambach Agar and SS Agar. The strains were then presumptively identified with API 20E strips (bioMerieux). Results: The results of this study allowed to make a qualitative evaluation and provide information on the presence/absence of microorganisms associated with pathogenicity in humans in surface waters. The concentration of Enterobacteriaceae colonies ranged from 2 o 10' to 4.5 o 10s in 100 ml of water. The highest number of Enterobacteriaceae was noticed in August and September (except bathing season 1996). The most abundant species were: Enterobacter cloacae, Enterobacter agglomerans, Escherichia coli and Citrobacter diversus. During the bathing period, relatively lower incidence of Escherichia coli (15%) could be ascribed to contamination from different additional sources and/or by excrements of sick people or disease carriers. The overall presence of Salmonella spp. recovered 22.6% of total (160) water samples; higher frequencies of this genus were found in those sites, which were situated close to villages and animal farms. The public bath areas in northern part of Wigry Lake (called Northern Ploso) showed the highest number of the waterborne bacterial from Enterobacteriaceae family. The Czarna Hańcza River, which brings a lot of pollution to northern part of Wigry Lake has immense influence on the sanitary state of Wigry Lake. The presence of pathogenic bacteria in absence of fecal coliforms, confirms that sanitary evaluation of water based exclusively on numbers of indicatory bacteria is not sufficient.
EN
Sensitivity to chemotherapeutic agents of 57 strains of Enterobacteriaceae isolated from different food products was examined. Significant differences of sensitivity in particular chemotherapeutic agents were found. The largest number of strains was resistant to penicillin (94.7% of all isolated strains). The percentage of strains resistant to trimethoprim was 63.2%, rifampicin - 56%, sulfamethoxazole - 47.4%, ampicillin - 42.1% and erythromycin - 38.6%. Lower percentages of strains were resistant to nitrofurantoin (26.3%), carbenicillin (22.8%), chloramphenicol (14%), oxytetracycline (12.3%), doxycycline and biseptol (10.5%), colistyn (8.8%). The resistance to neomycin, nalidixic acid and gentamycin was to not detected among the isolated strains.
PL
W biologicznych badaniach lipopolisacharydów (LPS), aktywność powszechnie wyrażana jest w jednostkach masy, bez uwzględnienia przeliczników molowych. Jest to szczególnie ważne przy porównywaniu preparatów różniących się długością łańcucha cukrowego i co się z tym wiąże, średnią zawartością lipidu A w cząsteczce, będącego aktywnym centrum endotoksyny. Zastosowanie ekwimolarnych dawek LPS pozwoliłoby na określenie wpływu zarówno wielkości jak i struktury części wielocukrowej na aktywność całego polimeru.
EN
In the paper, we propose a method for estimation of the mean molecular weight of lipopolysaccharide, which is important for accuracy of endotoxin activity investigation. In our study, it was assumed that lipid A portion in Enterobacterial lipopolysaccharide is substituted by four 3-hydroxytetradecanoic acid residues, Lipopolysaccharides of S, Ra, Rc and Re chemotypes being laboratory preparations as well as purchased from Sigma were investigated. Fatty acids were determined by of gas chromatography as methyl esters according to the procedure described by Wollenweber and Rietschel. Mean molecular weight was calculated by the formula: MMW = 4x10¬6 ng/mg NnM/mg . A high agreement between the estimated and the theoretical molecular weight values was demonstrated in the case of Salmonella minnesota R595 (Re) LPS preparation. As expected, LPS heterogeneity increase together with enlargement of polysaccharide chain lenght which is visible in electrophoregrams also. Except for LPS mean molecular weight estimation, the method allows its detection in various preparations and samples, distinguishing of R and S LPS forms as well as the determination of mean lenght of O-specific chain in lipopolysaccharides which structures are known.
EN
Our previous studies showed that glycerol fermentation by Hafnia alvei AD27 strain was accompanied by formation of high quantities of lactate. The ultimate aim of this work was the elimination of excessive lactate production in the 1,3-propanediol producer cultures. Group II intron-mediated deletion of ldh (lactate dehydrogenase) gene in an environmental isolate of H. alvei AD27 strain was conducted. The effect of the Δldh genotype in H. alvei AD27 strain varied depending on the culture medium applied. Under lower initial glycerol concentration (20 gL-1), lactate and 1,3-propanediol production was fully abolished, and the main carbon flux was directed to ethanol synthesis. On the other hand, at higher initial glycerol concentrations (40 gL-1), 1,3-propanediol and lactate production was recovered in the recombinant strain. The final titers of 1,3-propanediol and ethanol were similar for the recombinant and the WT strains, while the Δldh genotype displayed significantly decreased lactate titer. The by-products profile was altered upon ldh gene deletion, while glycerol utilization and biomass accumulation remained unaltered. As indicated by flow-cytometry analyses, the internal pH was not different for the WT and the recombinant Δldh strains over the culture duration, however, the WT strain was characterized by higher redox potential.
EN
Edwardsiella ictaluri is a Gram-negative bacterium and the causative agent of enteric septicemia of catfish. In this study, we examined the expression and function of the LuxS from a pathogenic E. ictaluri strain, J901. J901 was found to produce autoinducer 2 (AI-2) activity that maximized at mid-logarithmic phase and was enhanced by glucose and repressed by high temperature. Consistently, a luxS gene (luxSEi) was identified in J901, whose expression was regulated by cell density, glucose, and temperature in a manner similar to that observed with AI-2 activity. Further analysis showed that LuxSEi is a biologically active AI-2 synthase that was able to complement the luxS-defective phenotype of Escherichia coli DH5. To examine the functional importance of LuxSEi, a genetically modified variant of J901, J901Ri, was constructed, in which luxSEi expression was blocked by RNA interference. Compared to the wild type, J901Ri was (i) reduced in AI-2 activity to a level of 59% of that of the wild type; (ii) impaired in both planktonic and biofilm growth; (iii) significantly attenuated in the ability to infect cultured fish cells and to cause mortality in infected fish; (iv) unable to induce the expression of certain virulence-associated genes. Addition of exogenous AI-2 failed to rescue the growth defect of J901Ri as free-living cells but restored biofilm production and the expression of virulence genes to levels comparable to those of the wild type. Taken together, these results indicate that LuxSEi is a functional AI-2 synthase that is required for optimal cellular growth and host infection.
EN
In the study we tested drug sensitivity to 3 carbapenems (doripenem, imipenem and meropenem) of Gram-negative clinical isolates from Southern Poland. Material and methods. 89 strains were examined: 42 from Pseudomonas genus, 16 Acinetobacter baumannii strains and 31 Enterobacteriaceae strains. Etests were used according to the producers instructions, MIC values were interpreted using EUCAST criteria. Results. Highest in vitro activity against Pseudomonas spp. was shown for doripenem, then meropenem and the lowest for imipenem (MIC values were definitely lower for doripenem; differences were statistically significant); A. baumannii strains showed similar sensitivity to doripenem, meropenem and imipenem (differences non-significant); all Enterobacteriaceae strains showed sensitivity to the tested antimicrobials. Conclusions. As a conclusion-doripenem, which has high in vitro activity (almost the same as imipenem and meropenem) as well as beneficial pharmacologic properties, may be an alternative solution in the treatment of multiresistant Gram-negative bacteria, especially in patients in severe status who require restrictive antibiotic regimens.
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