An identification system was developed for enterobacteria isolated frequently from hospital patients, involving a set of biochemical reactions on agar media. The media were inoculated by a replication apparatus also used for setting up antibiotic sensitivity tests. Cultures in a control series showed a close correlation between reactions on the agar media and classical tests in a fluid medium. Of a series of 2668 laboratory isolates of enterobacteria, 2292 were identified outright by the selected reactions, 160 required one further test, and 216 could be identified only after repeating the reactions or the performance of additional tests. The identification has the advantages of speed, economy, and simplicity and is recommended for hospital laboratories handling large numbers of enterobacterial cultures.

Several strains of gram-negative bacteria (seven genera, eight species) isolated from patients with urinary tract infections were found to hydrolyze myeloma immunoglobulin A (IgA) protein. Human IgG and IgM and colostrum IgA were not degraded by these organisms. Examination of cleavage digests showed two fragments of different electrophoretic mobilities, with antigenic reactivity and sodium dodecyl sulfate polyacrylamide gel electrophoresis profiles consistent with their identification as Fc and Fab components. The immunoelectrophoresis patterns of cleavage digests suggested that the proteases responsible for this hydrolysis may be dissimilar in the specificity of their IgA cleavage sites.

A method is described for the separation and isolation of two electrophoretically distinct arylsulfatases (arylsulfatase EC.3.1.6.1) from Pseudomonas aeruginosa.Characterization of the enzymes revealed that they were type I arylsulfatases, with similar kinetic properties. They differed, however, in respect to charge, pH optima for substrate hydrolysis, and activation by anions. In addition, the enzymes displayed dual pH optima curves with both substrates used and the curious property of a shift in pH optima with varied p-nitrophenyl sulfate concentrations.

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A new compound, indoxyl-p-D-glucuronide, was assessed as a substrate for the rapid detection ofEscherichia coli in urine. Incorporation of this compound into MacConkey agar allowed the direct differentiation of E. coli as deep blue colonies distinct from lactose and nonlactose fermenters. The sensitivity was 88 to 90%, and the specificity was 100%.