title: Rapid microbiological assay for chloramphenicol and tetracyclines.
abstract: An agar diffusion assay for chloramphenicol and tetracyclines is described, using inhibition of hemolysis by Clostridium perfringens as a biological indicator of antimicrobial activity. Well-defined zones formed after a 1.5- to 2-h incubation in an anaerobic chamber or after 3 h using a GasPak system. Serum levels of chloramphenicol as low as 2.0 mug/ml could be reproducibly determined with this method. Concurrent presence of gentamicin did not influence the assay. Levels of penicillin G were also reproducibly determined with this method, although use of stable zones of growth inhibition which would form after overnight incubation were a more convenient end point for this bactericidal drug. The hemolytic assay with C. perfringens is a reproducible, accurate, and rapid method for determination of levels for chloramphenicol and tetracyclines.
mesh_terms: D001681:Biological Assay; D002701:Chloramphenicol / Q000494:pharmacology*; D003016:Clostridium perfringens / Q000187:drug effects; D003470:Culture Media; D005839:Gentamicins / Q000494:pharmacology; D006461:Hemolysis / Q000187:drug effects; D008722:Methods; D010400:Penicillin G / Q000032:analysis; D013754:Tetracyclines / Q000494:pharmacology*
chemical_list: D003470:Culture Media; D005839:Gentamicins; D013754:Tetracyclines; D002701:Chloramphenicol; D010400:Penicillin G