Antibiotics blocking bacterial cell wall assembly (beta-lactams and glycopeptides) are facing a challenge from the progressive spread of resistant pathogens. Lantibiotics are promising candidates to alleviate this problem. Microbisporicin, the most potent antibacterial among known comparable lantibiotics, was discovered during a screening applied to uncommon actinomycetes. It is produced by Microbispora sp. as two similarly active and structurally related polypeptides (A1, 2246-Da and A2, 2230-Da) of 24 amino acids linked by 5 intramolecular thioether bridges. Microbisporicin contains two posttranslational modifications that have never been reported previously in lantibiotics: 5-chloro-trypthopan and mono- (in A2) or bis-hydroxylated (in A1) proline. Consistent with screening criteria, microbisporicin selectively blocks peptidoglycan biosynthesis, causing cytoplasmic UDP-linked precursor accumulation. Considering its spectrum of activity and its efficacy in vivo, microbisporicin represents a promising antibiotic to treat emerging infections.

BI 397 (formerly A-A-1) is a semisynthetic derivative of the teicoplanin-like glycopeptide A40926. It was more active in vitro against staphylococci (including some teicoplanin-resistant strains) than teicoplanin and vancomycin. Against streptococci (including penicillin-resistant strains) BI 397 has activity comparable with that of teicoplanin and better than vancomycin. BI 397, when administered to rats by the i.v. route, gives high and long lasting blood levels. It shows excellent activity in models of acute septicaemia in immunocompetent and neutropenic mice. In a rat staphylococcal endocarditis model it is as effective as teicoplanin and vancomycin at reducing bacterial loads in the heart, but at lower dosages and with a reduced number of daily treatments compared with the two glycopeptide controls. BI 397 is highly efficacious in clearing penicillin-susceptible and -resistant pneumococci from lungs of immunocompetent and neutropenic rats. The data from these studies show that BI 397 combines an excellent in-vitro antibacterial activity with favourable pharmacokinetic behaviour resulting in potent in-vivo activity.

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The description of the genus Kineosporiu is amended after chemotaxonomic and morphological studies of the type strain of the type species, Kineosporiu uurantiucu JCM 3230. This organism yielded both LL-and rneso-diaminopimelic acids, which suggested that the former is present in the mycelium and the latter is present in the spores. There was no characteristic sugar pattern. A diagnostic phospholipid was phosphatidylcholine, and a major menaquinone component was MK-9(H4). No iso/anteiso branched fatty acids and no mycolic acids were observed. Colonies on agar lacked aerial mycelia, formed central projections including spores, and were occasionally accompanied by bunches of spore clusters in the agar. Spores were catenated or were located singly or aggregately at the tips of the vegetative hyphae. Our data indicate that the strain representative of the genus Kineosporiu shows some similarity to the spore dome actinomycetes described by Willoughby and by Makkar and Cross.The name Kineosporia aurantiaca was proposed by Pagani and Parenti in 1978 (11) for an actinomycete that lacked aerial mycelia and bore numerous sporangia, each of which contained a single zoospore, on the substrate mycelia. Analyses of the cellular components in the original description showed the presence of glycine and LL-diaminopimelic acid (A,pm) in the cell walls and arabinose, galactose, and xylose in the whole organism. Pagani and Parenti emphasized the structure of the sporangium of their strain, compared with the sporangia of the other sporangium-forming actinomycetes, and consequently placed it in the new genus Kineosporia .Recently, Hasegawa et al. (4) reported that whole cells of K . aurantiaca contain two isomers of A,pm, the LL and meso forms, but lack arabinose and xylose. Our analyses agree with the analyses of these authors. In addition, we observed that the spores are catenated or form aggregately at the tips of hyphae.Therefore, the description of the genus Kineosporia should be revised, and further studies on K . aurantiaca should be undertaken. We studied this organism to gain a better understanding of the taxonomy of the monospecific genus Kineosporia . MATERIALS AND METHODSStrain used, cultivation, and spore collection. K . aurantiaca JCM 3230T (= KCC A-0320T = Ah0312 Pagani and ParentiT) (T = type strain) was cultivated in yeast extract-glucose broth containing 10 g of yeast extract (Difco Laboratories, Detroit, Mich.) and 10 g of glucose in 1,000 ml of distilled water (pH 7.2) at 28°C for 5 to 6 days and then harvested by centrifugation. The biomass consisted of mycelial mats and numerous zoospores; this preparation was designated whole cultured organism.Spores were collected from a spread culture grown on a dilute yeast extract-starch agar plate containing 0.5 g of yeast extract (Daigo Eiyo, Osaka, Japan), 2.5 g of soluble starch, and 15 g of agar in 1,000 ml of distilled water (pH 7.3) at 25°C for 6 days. The spread culture was dipped in distilled water, and the surface was lightly scratched to promote the release of m...

Actinoplanes sp. ATCC 33076 is a new strain that was found to produce an antibiotic, designated A-16686, which is a complex of three closely-related polypeptides containing chlorinated phenyl moieties and D-mannose. Both the complex and the single fractions possess a good activity against Gram-positive bacteria. A-16686 specifically inhibits the synthesis of the bacterial cell wall. Culture media* Medium No. 2 (yeast extract-malt agar)

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