A penicillinase test incorporated in the rapid carbohydrate fermentation method for rapid detection of beta-lactamase producing Neisseria gonorrhoeae.

A modification of the acidometric (phenol red) test for penicillinase producing N. gonorrhoeae was incorporated into the rapid fermentation method for rapid screening and identification of PPNG strains. Two hundred and twenty-four non-penicillinase-producing N. gonorrhoeae, 55 penicillinase-producing N. gonorrhoeae, 87 N. meningitidis and 89 N. lactamica were included in this study. Results of the modified test were comparable with the iodometric and penicillin disk diffusion susceptibility and were obtainable within 1 to 5 minutes.

Isolation of Salmonella typhi from standard whole-blood culture vs blood-clot cultures.

The use of 10% oxgall and bile broth medium, both supplemented with freshly prepared 100 u/ml streptokinase, for isolating Salmonella typhi by clot culture technique was evaluated and compared against whole blood culture systems (3 ml blood in 9 ml media and 8 ml blood in 72 ml media). These gave a 1:4 and 1:10 blood to medium ratio, respectively. Clot cultures in 10% oxgall (CLOX) gave a 57% positive isolation rate for S. typhi. A similar result was obtained from clot cultures in bile broth medium (CLBB). A total of 184 samples identified as positive for S. typhi were tested. There was no significant difference between the use of 10% oxgall or bile broth medium when used for clot culture. The whole blood culture systems still showed a significantly better rate of isolation than the clot culture methods.

Variation in the hemolytic activity of Leptospira interrogans serovar canicola.

Leptospira interrogans serovar canicola strain moulton was grown to a high cell density in a protein-free medium with hemin. The hemolysin produced in this culture system showed a greatly expanded spectrum of hemolysis as compared to previous reports of leptospiral hemolysin produced in a more traditional culture system containing serum.

Hemolysin production by Leptospira interrogans serovar canicola in a protein-free medium with hemin.

Leptospira interrogans serovar canicola strain moulton was grown to a high cell density in a protein-free medium. When hemin was added to this medium, hemolysin was produced. Hemolysin was not detected when other porphyrins or cytochrome C were substituted for hemin in the medium.