Superoxol and aminopeptidase tests for identification of pathogenicNeisseria species andMoraxella (Branhamella) catarrhalis

Abstract

The superoxol test, and prolyl aminopeptidase and gammaglutamyl aminopeptidase tests were evaluated for the detection of pathogenic Neisseria spp. using 317 strains of Neisseria-ceae. The superoxol test was positive for all 116 gonococci and 62 Moraxella (Branhamella) catarrhalis strains, but also for three strains of Neisseria meningitidis, one strain of Neisseria lactamica and eight saprophytic neisseriae. When using strains grown on Thayer-Martin medium, the positive and negative predictive values of the superoxol test for the identification of Neisseria gonorrhoeae were 96.7% and 100% respectively. Meningococci were the only neisseriae growing on Thayer-Martin medium that showed gamma-glutamyl aminopeptidase activity. The prolyl aminopeptidase test showed low specificity.

Kinetics of catalyzed hydrolysis of 4-methylumbelliferyl caprylate (MUCAP) salmonella reagent

“…The majority of salmonella strains of all species and serotypes were capable of cleaving esters of the coumarin derivative 4-MU with esterase with particular activity on caprilate derivatives. Identifying salmonella in the clinical laboratories involves the use of 4-methylumbelliferyl caprylate (MUCAP); a substrate that fluoresces upon hydrolysis of the ester bond [28]. The enzyme acts on a substrate formed by an ester of 8 atoms of carbon conjugated with 4-MU, librating this last compound, which is strongly fluorescent and can be observed after 3-5 min under a UV lamp (wavelength, 366 nm).…”