PubMed Health⌕ Search

Biomedical subjects

J M Singer

Publications and source records attributed to J M Singer.

At least 55 records · Page 3Linked to original sources
PubMed1977

The use of bile - esculin agar for the taxonomic classification of the family Enterobacteriaceae.

Bile-esculin medium has been used for many years for the presumptive identification of group D Streptococcus. The test is based on the ability of a bacterium to grow in the presence of 40% bile and produce esculinase. 2935 strains of Enterobacteriaceae were inoculated onto bile-esculin agar slants and incubated at 35 C. Esculin hydrolysis was determined after 24 and 48 hours. At 24 hours of incubation esculin hydrolysis was limited to the genera Klebsiella, Enterobacter, Serratia, and the species P. vulgaris, P. rettgeri, and C. diversus. Not all strains of these species were positive, however. All other members of the family were negative. At 48 hours of incubation 37% of E. coli gave a positive reaction; all other Enterobacteriaceae which were negative at 24 hours remained negative. Esculin hydrolysis is a valuable test for the taxonomic classification of the family Enterobacteriaceae.

Bacteriological Techniques↗
PubMed1977

Esculin hydrolysis by Enterobacteriaceae.

Literature reports disagree concerning esculin hydrolysis in the family Enterobacteriaceae. A total of 2,490 strains of the family were investigated for esculin hydrolysis by two methods, the esculin spot test and the PathoTec incubation strip, which measures constitutive enzyme, and five growth-supporting methods, which determine both constitutive and inducible enzymes. The five growth-supporting media studied were: Vaughn-Levine, the standard esculin hydrolysis medium (P. R. Edwards and W. H. Ewing, Identification of Enterobacteriaceae, 3rd ed., 1972); Vaughn-Levine without iron; Vaughn-Levine without Andrade's indicator; and bile-esculin medium. Growth media were incubated at 35 degrees C and checked every 24 h for 120 h. On growth media, 0.3% of Escherichia coli were positive in 24 h, 34% in 48 h, and 61% in 120 h. No strains were positive on the "nongrowth" tests. It appeared that the esculin hydrolysis enzyme(s) of E. coli was inducible rather than constitutive. All esculin hydrolyzers, which yielded positive tests on "constitutive tests" and 24-h tests, were limited to the genera Klebsiella, Enterobacter, and Serratia and species of Proteus vulgaris, Proteus rettgeri, and Citrobacter diversus. When used with standardized inoculum size and incubation time, the esculin hydrolysis test is very useful for differentiation within the family Enterobacteriaceae.

Citrobacter↗
PubMed1977

Determination of antibody concentration using a stopped-flow turbidimetric technique.

The aggregation of albumin and anti-albumin is studied during the first seconds of the reaction by measuring the rate of change of the optical density of the mixture. When this rate is plotted against the antigen concentration of a constant serum dilution, bell-shaped curves are obtained. The maxima of these rate curves parallel the maxima of precipitation curves. Thus, the maximum rate establishes the antigen concentration for maximum precipitate. On the basis of these experiments a method for relative quantitation of antibody in sera is proposed. The absolute concentration of precipitating antibody can be obtained by means of an additional one-tube precipitation experiment.

Animals↗
PubMed1976

Pulmonary infection with Allescheria boydii.

Allescheria boydii, the most common fungus isolated from North American maduromycosis, is a well-described pathogen. Reports of its isolation from sites other than the extremities are rare. Only ten cases of pulmonary infection are recorded in the literature. Of these, two are primary infections, and eight are secondary. An eleventh case is reported. Although there are some elements in the patient's history that indicate that this infection is secondary, the authors regard the infection a primary one. A pathologic and microbiologic compendium of all 11 cases is presented.

Aged↗
PubMed1976

Rapid spot test for the determination of esculin hydrolysis.

Esculin hydrolysis is a useful test in the differentiation of both gram-positive and gram-negative bacteria covering a wide spectrum of aerobes, facultative anaerobes, and anaerobes. Commonly utilized methods require a minimum of 18 h of incubation in broth or agar medium and utilize the production of a brown-black compound, due to the combination of ferric ions with the hydrolysis product esculetin, as indicator. A procedure is presented that requires 15 to 30 min for completion and utilizes fluorescence loss as the indicator of hydrolysis. Esculin fluoresces at 366 nm, whereas the hydrolysis product esculetin does not. Over 1,400 strains of gram-positive and gram-negative bacteria were tested. There was 98.4% of correlation between the spot test and esculin broth and 97% correlation with the bile-esculin agar.

Aerobiosis↗
PubMed1975

Direct inoculation procedure for the rapid classification of bacteria from blood culture.

A procedure was developed for 4-h identification of bacteria from blood culture. From a turbid blood culture bottle a 10- to 15-ml aliquot was drawn off and centrifuged. The pellet was utilized to inoculate a series of enzymatic and physiologic reactions. Three hundred eight positive blood cultures were tested including 222 strains of Enterobacteriaceae, 40 strains of facultative grampositive cocci, 26 strains of anaerobes, and 20 assorted strains. There was over 96.5% agreement between 4-h and conventional methods with the Enterobacteriaceae, 98% with facultative gram-positive cocci, 100% with anaerobes, and 99% with the assorted strains.

Bacteria↗