virginiamycin and etamycin

Griseoviridin, a known antibiotic produced by Streptomyces cacaoi subsp. cacaoi, was found to be active against Brachyspira hyodysenteriae--the bacterium causing swine dysentery. An in vitro synergism is observed when it is used in combination with viridogrisein--a simultaneously produced antibiotic. In mouse experiments, the effect of griseoviridin alone was less than that of lincomycin--a commercially available swine dysentery medication. However, a 1:1 mixture of griseoviridin and viridogrisein revealed a noticeable synergistic effect. In an evaluation using pigs artificially infected with B. hyodysenteriae, a large difference was not observed between the effect of griseoviridin alone and that in combination with viridogrisein. Nevertheless, griseoviridin alone exhibited a therapeutic effect superior to that of lincomycin.

Topics: Animals; Anti-Bacterial Agents; Drug Synergism; Dysentery; Lincomycin; Macrolides; Male; Mice; Mice, Inbred Strains; Microbial Sensitivity Tests; Molecular Structure; Peptides; Specific Pathogen-Free Organisms; Spirochaetales; Spirochaetales Infections; Swine; Swine Diseases; Virginiamycin

A fluorescence assay for streptogramin B lyase, an enzyme that confers resistance to streptogramin B antibiotics, has been developed. The antibiotic substrates are fluorescent and the linear peptide products formed in the lyase-catalyzed reaction are relatively nonfluorescent. The assay has potential for assessing bacterial resistance to streptogramin B antibiotics and will be utilized to direct the purification of streptogramin B lyase from bacterial extracts.

Topics: Anti-Bacterial Agents; Drug Resistance, Microbial; Intramolecular Lyases; Isomerases; Macrolides; Spectrometry, Fluorescence; Streptomyces; Substrate Specificity; Virginiamycin