Difficidin and oxydifficidin, two novel macrocyclic polyene lactone phosphate esters were discovered in fermentation broths of each of two strains of Bacillus subtilis: ATCC 39320 and ATCC39374. Difficidin and oxydifficidin each showed a broad spectrum of activity against aerobic and anaerobic bacteria. Manyof the susceptible aerobes and anaerobes were humanpathogens resistant to one or more antibiotics. Difficidin and oxydifficidin when administered intraperitoneally protected mice against an otherwise lethal bacteremia caused by Klebsiella pneumoniae (ED50 in mg/kg of 1.31 and 15.6 respectively).Neither difficidin nor oxydifficidin were effective when administered via the subcutaneous route.In the course of screening for new antibiotics, difficidin and oxydifficidin, two novel macrocyclic polyene lactone phosphate esters0, (Fig. 1)

GELRITE gellan gum (formerly known as PS-60 and S-60) is a new naturally derived, highly purified polysaccharide which displays several interesting properties, including selfgelling. The suitability of GELRITE as an agar substitute was tested by evaluating the performance of several media selected from among those most commonly used in the isolation, identification, and enumeration of microorganisms in clinical laboratories. Fifty different bacterial species previously implicated in human infections served as test strains. On the basis of the various parameters considered, namely, colony characteristics, biochemical reactions, hemolytic patterns, and plating efficiency, media gelled by agar and by GELRITE compared quite favorably.

The recently discovered class of cyclic hexadepsipeptide antibiotics is exemplified by azinothricin1) and A83586C2). In our search for novel substances with C5a antagonistic properties, a member of this class, L-156,602, was isolated from a newly isolated strain of streptomycete and found to be a competitive inhibitor of the binding of the anaphylatoxin C5a to its receptor on human PMNs3). Because of its broad range of biological properties, C5a has been implicated as a causative or aggravating agent in a variety of inflammatory and allergic diseases4'5) and an inhibitor of such inflammatory actions would therefore be therapeutically beneficial in the treatment of such diseases. The producing organism, MA-6348, was isolated from a plant rhizosphere soil sample obtained from a Japanese garden. Comparison of spectral data suggested the compound to be identical to PD 124,966, but no structure has been published6'7). We report here primarily on the structure determination of L-156,602 including absolute stereochemistry, based on spectroscopic and X-ray diffraction analyses. The culture was characterized by the International Streptomyces Project procedures described by Shirling and Gottlieb8*. Pigment production,

Efrotomycin is a narrow spectrum antibiotic. Among the genera tested for susceptibility in vitro it is most active against isolates of Moraxella, Pasteurella, Yersinia, Haeniophilus, Streptococcus and Corynebacterium. The drug is as active by oral administration as by the subcutaneous route. Blood levels rise rapidly to high concentrations, after oral dosing, and are prolonged. Two peaks occur which may indicate biliary excretion and reabsorption. Urinary excretion is minimal. The high blood concentrations explain, in part, the in vivo

Twenty-one strains of Campylobacter pylori (Campylobacter pyloridis) were tested for susceptibility to norfloxacin and other agents by the serial agar dilution method. Ampicillin (MIC for 90% of isolates [MIC901, 0.016 ,ug/ml) and famotidine (MIC90, >1,024 ,ug/ml) were, respectively, the most and the least active of the agents tested. Norfloxacin (MICg, 1 p,g/ml) and imipenem (MIC90, 0.125 p,g/ml) were substantially active against this organism.