Abstract: New peptide antibiotic A54145, individual A54145 components A, A.sub.1, B, B.sub.1, C, D, E and F and their pharmaceutically acceptable salts, are useful antibacterial agents which also improve growth performance in animals, especially poultry. Biologically pure cultures of the A54145-producing Streptomyces fradiae cultures NRRL 18158, NRRL 18159 and NRRL 18160 cultures and methods of making antibiotic A54145 using those cultures are also provided.

Abstract: Antibiotic A42125, which is produced by a new strain of Nocardia aerocolonigenes, NRRL 18049, is a useful inhibitor of Gram-positive and methane-generating microorganisms. A42125 also increases feed utilization efficiency in ruminants. A biologically purified culture of N. aerocolonigenes NRRL 18049 and a method for producing A42125 by fermentation of this culture are provided.

Abstract: Antibiotic A42125, which is produced by a new strain of Nocardia aerocolonigenes, NRRL 18049, is a useful inhibitor of Gram-positive and methane-generating microorganisms. A42125 also increases feed utilization efficiency in ruminants. A biologically purified culture of N. aerocolonigenes NRRL 18049 and a method for producing A42125 by fermentation of this culture are provided.

Abstract: Antibiotic A41030, a complex of 7 individual factors, is produced by submerged, aerobic fermentation of new Streptomyces virginiae NRRL 12525, and Streptomyces virginiae NRRL 15156. The antibiotic factors are separated and possess antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic factors have shown inhibition of Streptococcus pneumonia Park I. The complex and the individual factors enhance feed efficiency in ruminant animals, and are growth promoters in chickens and swine, and are especially valuable in milk production in dairy cattle.

Abstract: Antibiotic A47934 is produced by submerged, aerobic fermentation of new Streptomyces toyocaensis NRRL 15009. The antibiotic is active against gram-positive bacteria in vitro and in vivo. It promotes growth in poultry and swine and serves to enhance feed efficiency in ruminant animals having a developed rumen.

Abstract: Antibiotic A41030, a complex of 7 individual factors, is produced by submerged, aerobic fermentation of new Streptomyces virginiae NRRL 12525, and Streptomyces virginiae NRRL 15156. The antibiotic factors are separated and possess antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic factors have shown inhibition of Streptococcus pneumonia Park I. The complex and the individual factors enhance feed efficiency in ruminant animals, and are growth promoters in chickens and swine, and are especially valuable in milk production in dairy cattle.

Abstract: A new antibiotic of the rifamycin class, A39079 factor S-1, which has the structure ##STR1## is an effective broad-spectrum antibiotic and increases feed-utilization efficiency in animals.

Abstract: Antibiotic A41030, a complex of 7 individual factors, is produced by submerged, aerobic fermentation of new Streptomyces virginiae NRRL 12525, and Streptomyces virginiae NRRL 15156. The antibiotic factors are separated and possess antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic factors have shown inhibition of Streptococcus pneumonia Park I. The complex and the individual factors enhance feed efficiency in ruminant animals, and are growth promoters in chickens and swine, and are especially valuable in milk production in dairy cattle.

Abstract: Antibiotic A47934 is produced by submerged, aerobic fermentation of new Streptomyces toyocaensis NRRL 15009. The antibiotic is active against gram-positive bacteria in vitro and in vivo. It promotes growth in poultry and swine and serves to enhance feed efficiency in ruminant animals having a developed rumen.

Abstract: Antibiotic A41030, a complex of 7 individual factors, is produced by submerged, aerobic fermentation of new Streptomyces virginiae NRRL 12525, and Streptomyces virginiae NRRL 15156. The antiobiotic factors are separated and possess antibacterial activity against Staphylococcus and Streptococcus species which are penicillin resistant. In addition, the antibiotic factors have shown inhibition of Streptococcus pneumonia Park I. The complex and the individual factors enhance feed efficiency in ruminant animals, and are growth promoters in chickens and swine, and are especially valuable in milk production in dairy cattle.

Abstract: Antibiotic A54556, a complex of 8 individual factors, produced by submerged, aerobic fermentation of new Streptomyces hawaiiensis NRRL 15010. The complex and the individual, separated factors are active against Staphylococcus and Streptococcus which are penicillin resistant.

Abstract: Antibiotic A47934 is produced by submerged, aerobic fermentation of new Streptomyces toyocaensis NRRL 15009. The antibiotic is active against gram-positive bacteria in vitro and in vivo. It promotes growth in poultry and swine and serves to enhance feed efficiency in ruminant animals having a developed rumen.

Abstract: Antibiotic A-39183 complex, comprising microbiologically active, related factors A, B, C, D, and E, is produced by submerged, aerobic fermentation of a new microorganism Streptomyces sp., NRRL 12049. The A-39183 antibiotics are closely related antibiotics. The individual A-39183 factors are separated by chromatography. The A-39183 factors are antibacterial agents which have activity against Staphylococcus and Streptococcus species that are penicillin resistant. The A-39183 factors are also active against both gram-positive and gram-negative anaerobic bacteria, and are ionophores.

Abstract: Antibiotic A-39183 complex, comprising microbiologically active, related factors A, B, C, D, and E, is produced by submerged, aerobic fermentation of a new microorganism Streptomyces sp., NRRL 12049. The A-39183 antibiotics are closely related antibiotics. The individual A-39183 factors are separated by chromatography. The A-39183 factors are antibacterial agents which have activity against Staphylococcus and Streptococcus species that are penicillin resistant. The A-39183 factors are also active against both gram-positive and gram-negative anaerobic bacteria, and are ionophores.

Abstract: The new microorganism Streptomyces granuloruber, NRRL 12389 and the fermentation process for preparing narasin by submerged aerobic fermentation of this organism.

Abstract: The new microorganism Streptomyces lydicus DeBoer et al., NRRL 12034 and the fermentation process for preparing narasin by submerged aerobic fermentation of this organism.

Abstract: The microorganism Aspergillus nidulans var. roseus NRRL 11440 and the method of producing the A-30912 antibiotics by submerged aerobic fermentation of this microorganism to give the A-42355 antibiotic complex. A-30912 factors A, B, D, and H are separated from the A-42355 complex by chromatography. The A-42355 complex and A-30912 factors A, B, D, and H are antifungal agents.

Abstract: Antibiotic A-39183 complex, comprising microbiologically active, related factors A, B, C, D, and E, is produced by submerged, aerobic fermentation of a new microorganism Streptomyces sp., NRRL 12049. The A-39183 antibiotics are closely related antibiotics. The individual A-39183 factors are separated by chromatography. The A-39183 factors are antibacterial agents which have activity against Staphylococcus and Streptococcus species that are penicillin resistant. The A-39183 factors are also active against both gram-positive and gram-negative anaerobic bacteria, and are ionophores.

Abstract: Antibiotic A-38533 complex, comprising microbiologically active, related factors A.sub.1, A.sub.2, B and C, is produced by submerged, aerobic fermentation of a new Streptomyces sp., NRRL 11298. The A-38533 antibiotics are closely related antibiotics. The individual A-38533 factors are separated by chromatography. The A-38533 factors are antibacterial agents which have a unique activity against Pseudomonas species.