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PubMed1985

[Esculin hydrolysis, a confirmation test for fecal streptococci detected on Slanetz-Bartley medium].

Samples of marine waters have been analyzed for recovering faecal streptococci applying the membrane filtration technique on Slanatez-Bartley medium. It has been pointed out that this medium can yield high proportions of non-group D streptococci: in fact its selectivity seems to be rather low at least for certain samples. This study aims to test and to overcome the disadvantage of the high counts of faecal streptococci due to background microrganisms. The hydrolysis of esculin may be used as a confirmatory test for increasing the selectivity. Membranes showing high numbers of streptococci-like colonies have been transferred from Slanetz-Bartley (MEA) medium to an esculin iron agar (EIA) plate. After 20 min at 41 degrees C small black spots appeared on the backside of the membrane where the colonies had hydrolyzed esculin were resident. The number of positive colonies may be recorded as the real number of faecal streptococci.

Esculin↗
PubMed1997

Fish meal extract bile esculin agar (FMBE) a selective medium for Bacteroides fragilis group.

Fish meal extract bile esculin agar (FMBE) is prepared using Fish meal extract concentrate as the basal substance, for the selective isolation and presumptive identification of B.fragilis group. The efficiency of the medium was evaluated by growing stock cultures of B.fragilis groups as well as inoculating clinical specimens and comparing the results with Bacteroides bile esculin agar (BBE). All the 87 stock cultures of B.fragilis grew on FMBE and BBE. No other anaerobes tested grew on the medium. However 7 out of 65 neomycin resistant aerobes grew on the FMBE. From the 100 clinical samples, 62 strains of B. Fragilis group were recovered on FMBE and BBE, and 53 strains on supplemented BHIBA. The cost effectiveness, selectivity and the ability to detect esculin hydrolysis will enable FMBE as a suitable medium as comparable to that of BBE, if not superior.

Agar↗
PubMed1976

Esculin hydrolysis by Streptococcus dysgalactiae.

In a mastitis control program based on eradication of intramammary infection, it is important to differentiate streptococci. According to earlier reports, Streptococcus dysgalactiae was unable to hydrolyze esculin. Preliminary data from the present study indicated that under optimal conditions, some strains of S dysgalactiae were capable of esculin hydrolysis. In a study of 45 strains of S dysgalactiae, 55.5% were able to hydrolyze esculin. In the past, these organisms would probably have been identified as Streptococcus uberis. Streptococcus dysgalactiae is more sensitive to antibiotics than S uberis, and the infection is easier to eradicate from infected glands.

Culture Media↗
PubMed1970

Presumptive identification of group D streptococci: the bile-esculin test.

Six tests commonly used for the presumptive identification of group D streptococci were evaluated. Strains tested included 282 group D streptococci and 366 non-group D. Ratios of percentages of group D to non-group D strains which gave positive reactions for each test are as follows: bile-esculin, 100:2; salt tolerance, 88:24; heat tolerance, 100:80; SF broth, 86:1; KF broth, 99:40; and methylene blue milk reduction, 90:17. These data indicate that the bile-esculin test provided a reliable means of identifying group D streptococci and differentiating them from non-group D streptococci. Methodology for reading and interpreting positive reactions and time of incubation of the bile-esculin medium was defined. Evidence of the need for standardization of salt and heat-tolerance tests was obtained.

Agar↗
PubMed1980

Simple disk technique for carbohydrate fermentation and esculin hydrolysis testing of anaerobic gram-negative bacilli.

Carbohydrate fermentation by anaerobic gram-negative bacilli was easily detected using Taxo-Disks placed on supplemented Columbia Agar. After incubation, two drops of a 0.2% solution of bromothymol blue were added to each disk: yellow coloring was indicative of a positive reaction. In the esculin hydrolysis test paper disks impregnated with 2 mg of esculin were placed on the same medium. The results were read after addition of two drops of a 10% solution of ferric chloride. When testing slow-growing and/or serophilic anaerobic gram-negative bacilli, such as Bacteroides melaninogenicus or Bacteroides oralis, the supplemented Columbia Agar was enriched with 10% sterile horse serum. Discrepancies between results with the conventional tube technique and the disk method were occasionally observed with salicin only.

Bacteriological Techniques↗
PubMed2005

Separation and simultaneous determination of rutin, puerarin, daidzein, esculin and esculetin in medicinal preparations by non-aqueous capillary.

A simple method for the simultaneous determination of five bioactive components (rutin, puerarin, daidzein esculin and esculetin) in traditional medicinal preparations by non-aqueous capillary electrophoresis with UV detection has been developed for the first time. A running buffer composed of 15% acetonitrile, 2.5% acetic acid and 90 mM sodium cholate in methanol was found to be the most suitable for this separation. The limits of detection for five analytes were over the range of 0.050-1.216 microg ml(-1). The relative standard deviations (R.S.Ds.) of the migration times and the peak areas of the analytes were in the range of 1.3-2.9% and 2.2-2.7% (intraday), 1.7-1.9% and 2.8-3.6% (interday), respectively. In the tested concentration range, linear relationships (correlation coefficients: 0.9974 for rutin, 0.9976 for puerarin, 0.9981 for daidzein, 0.9972 for esculin and 0.9929 for esculetin) between peak areas and concentrations of the analytes were obtained. This method has been successfully applied to simultaneous determination of the five bioactive components with recoveries over the range of 89.4-107.4%.

Electrophoresis, Capillary↗
PubMed1995

Modification of kanamycin-esculin-azide agar to improve selectivity in the enumeration of fecal streptococci from water samples.

Kanamycin-esculin-azide agar was modified by increasing the concentration of sodium azide to 0.4 g liter-1 and replacing kanamycin sulfate with 5 mg of oxolinic acid liter-1. The modification, named oxolinic acid-esculin-azide (OAA) agar, was compared with Slanetz-Bartley and KF agars by using drinking water and seawater samples. The OAA agar showed higher specificity, selectivity, and recovery efficiencies than those obtained by using the other media. In addition, no confirmation of typical colonies was needed when OAA agar was used, which significantly shortens the time of sample processing and increases the accuracy of the method.

Agar↗
PubMed1992

Pyrazinamidase, CR-MOX agar, salicin fermentation-esculin hydrolysis, and D-xylose fermentation for identifying pathogenic serotypes of Yersinia enterocolitica.

We evaluated several simple laboratory tests that have been used to identify pathogenic serotypes of Yersinia enterocolitica or to indicate the pathogenic potential of individual strains. A total of 100 strains of Y. enterocolitica were studied, including 25 isolated during five outbreak investigations, 63 from sporadic cases, and 12 from stock cultures. The pyrazinamidase test, which does not depend on the Yersinia virulence plasmid, correctly identified 60 of 63 (95% sensitivity) strains of pathogenic serotypes and 34 of 37 (92% specificity) strains of nonpathogenic serotypes. Salicin fermentation-esculin hydrolysis (25 degrees C, 48 h) correctly identified all 63 (100% sensitivity) strains of the pathogenic serotypes and 34 of 37 (92% specificity) strains of the nonpathogenic serotypes. The results of the pyrazinamidase and salicin-esculin tests disagreed for only 7 of the 100 strains of Y. enterocolitica, and these would require additional testing. Congo red-magnesium oxalate (CR-MOX) agar determines Congo red dye uptake and calcium-dependent growth at 36 degrees C, and small red colonies are present only if the strain contains the Yersinia virulence plasmid. This test has proven to be extremely useful for freshly isolated cultures, but only 15 of 62 strains of pathogenic serotypes that had been stored for 1 to 10 years were CR-MOX positive. None of the 16 strains of Y. enterocolitica serotype O3 fermented D-xylose, so this test easily differentiated strains of this serotype, which now appears to be the most common in the United States. Although antisera that can actually be used to serotype strains of Y. enterocolitica are not readily available, the four simple tests described above can be used to screen for pathogenic serotypes.

Agar↗
PubMed1998

Bile-esculin test for presumptive identification of enterococci and streptococci: effects of bile concentration, inoculation technique, and incubation time.

The bile-esculin test is used to differentiate enterococci and group D streptococci from non-group D viridans group streptococci. The effects on test performance of the concentration of bile salts, inoculum, and duration of incubation were examined with 110 strains of enterococci, 30 strains of Streptococcus bovis, and 110 strains of non-group D viridans group streptococci. Optimal sensitivity (> 99%) and specificity (97%) of the bile-esculin test can be obtained with a bile concentration of 40%, a standardized inoculum of 10(6) CFU, and incubation for 24 h.

Bile↗
PubMed1994

Detection of beta-Glucosidase Activity in Polyacrylamide Gels with Esculin as Substrate.

beta-Glucosidase can be located after nondenaturing polyacrylamide gel electrophoresis by incubating the gel with 0.1% esculin and 0.03% ferric chloride. The esculetin released from esculin by beta-glucosidase action reacts with ferric ion to produce a black band, corresponding to the beta-glucosidase, against the transparent background.

Journal Article↗
PubMed2004

Characterization of esculin-positive Pseudomonas fluorescens strains isolated from an underground brook.

A group of sixteen esculin-positive fluorescent pseudomonads isolated from an underground brook flowing through a cave complex was characterized by biotyping, multiple enzyme restriction fragment length polymorphism analysis of 16S rDNA (MERFLP), ribotyping and whole-cell fatty-acid methyl-esters analysis (FAME). All strains were phenotypically close to Pseudomonas fluorescens, but they revealed high biochemical variability as well as some reactions atypical for P. fluorescens species. Because identification of pseudomonads by of biochemical testing is often unclear, further techniques were employed. Fingerprints obtained by MERFLP clearly showed that all strains represent P. fluorescens species. Ribotyping separated the strains analyzed into four groups corresponding almost completely (with the exception of one strain) to the clustering based on biochemical profiles. FAME analysis grouped all the strains into one cluster together with the P. putida (biotype A, B), P. chlororaphis and P. fluorescens biotype F representatives, but differentiated them from other FAME profiles of all pseudomonads included in the standard library TSBA 40 provided by MIDI, Inc.

Bacterial Typing Techniques↗
PubMed1995

Effect of a total extract from Fraxinus ornus stem bark and esculin on zymosan- and carrageenan-induced paw oedema in mice.

This study investigates the total ethanol extract (TE) of the stem bark of Fraxinus ornus and its constituent esculin (EN). They inhibited classical pathway (CP) and alternative pathway (AP) of complement activation in mouse serum. After intraperitoneal administration the total extract displayed antiinflammatory activity in both zymosan- and carrageenan-induced paw oedema in mice. The results suggest that the traditional use of Fraxinus ornus stem bark extracts in the treatment of inflammatory disorders is at least partially due to its coumarin constituents.

Animals↗
PubMed1993

Simultaneous isolation of Rutin and Esculin from plant material and drugs using solid-phase extraction.

Simultaneous isolation of Rutin and Esculin from pharmaceutical materials (plant--Flos hippocastani and drugs--Venescin, Venacorn) using solid-phase extraction (SPE) have been made. For this investigation the Bakerbond SPE columns with different unpolar and polar chemically bonded phases were used. On the basis of isolation investigation the influence of SPE packing materials on the selectivity change and recovery of both extracted substances were studied.

Chemistry, Pharmaceutical↗
PubMed1987

Sodium chloride-esculin hydrolysis test for rapid identification of enterococci.

The ability of enterococci to cause severe disease in humans and their relative resistance to chemotherapeutic agents make it desirable to rapidly differentiate these organisms from other streptococci. We developed and evaluated a test that within 2 h distinguishes enterococci from other alpha-, beta-, or nonhemolytic streptococci in a buffered solution containing 0.2% esculin and 5% sodium chloride. All 239 strains of enterococci tested gave a positive reaction within 2 h, whereas 95 of 96 isolates of other streptococci remained negative at 4 h.

Esculin↗
PubMed1998

Evaluation of the oxolinic acid--esculin--azide medium for the isolation and enumeration of faecal streptococci in a routine monitoring programme for bathing waters.

m-Enterococcus agar (m-Ent) has been generally considered the reference medium for faecal streptococci in bathing waters. However, it shows several shortcomings, and therefore it is important to test newly developed media that can guarantee more precise results. In this sense, the recently described oxolinic acid--esculin--azide agar medium (OAA) and m-enterococcus agar (m-Ent) were comparatively evaluated for the detection of faecal streptococci from seawater and fresh water. The OAA medium showed a significantly higher relative recovery percentage and specificity for both types of water than m-Ent. A similar spectrum of species was recorded from both media, Enterococcus faecium being predominant in fresh water and Enterococcus faecalis, in seawater. The superior performance of the OAA medium in both types of bathing waters, added to the fact that it does not require the use of complementary confirmative tests, makes this medium an excellent candidate to be employed for monitoring programmes.

Azides↗
PubMed1989

[Effectiveness of ClNa-esculin broth for the rapid identification of the Enterococcus genus].

The efficacy of the ClNa-esculine broth for the rapid identification (2 hours) of the species of the genus Enterococcus was evaluated and compared with the conventional biochemical methods requiring an incubation of 18-24 hours. Out of the 274 evaluated strains, 171 were positive for this investigation; 160 of them corresponded to Enterococcus spp (100%). The sensitivity of the test was 100%, the specificity 99.1%, the positive predictive value 99.3% and the negative predictive value 100%.

Culture Media↗