[Studies on detection methods for Legionella species from environmental water]

We investigated selective cultivation media and previous treatments of samples suitable for detection of Legionella species from environmental water and for elimination of co-existing microbes which gave rise to an interference with the evaluation of Legionella sp. growth. Twenty thousand U of polymyxin B (PL-B)/ml and 100 micrograms of oxytetracycline (OTC)/ml seem to be useful as additives to MWY selective agar medium. Both antibiotics markedly inhibited the growth of co-existing microbes with almost no influence on the growth of Legionella sp. In the studies on the resistance of 8 strains of Legionella sp., 24 strains of co-existing microbes and 2 standard strains of Staphylococcus aureus and Escherichia coli to acid treatment (0.2 M HCl-KCl, pH 2.2, 25 degrees C, 4 minutes) and heating (50 degrees C, 20 minutes), acid treatment or heating alone showed no inhibition on the growth of almost all strains examined. However, combination with acid treatment after heating resulted in an apparent extinction of almost all microbes except for Legionella sp., Seven strains from co-existing microbes showed an apparent growth inhibition against 8 strains of Legionella sp. with different serotypes and were all identified as Pseudomonas aeurginosa, which were all eliminated by means of the combination with acid treatment after heating. From these results, it was concluded that the combined pre-treatment of water samples with acid after heating and the addition of PL-B and OTC into the selective cultivation medium is an useful method for detection of Legionella sp. from environmental water.

Boromycin, an anti-HIV antibiotic

The polyether-macrolide antibiotic, boromycin, was isolated as a potent anti-human immunodeficiency virus (HIV) antibiotic from a fermentation broth of Streptomyces sp. A-3376. Boromycin was found to strongly inhibit the replication of the clinically isolated HIV-1 strain as well as the cultured strain in in vitro laboratory experiments. The mechanism for the anti-HIV activity of boromycin is suggested to involve blocking the later stage of HIV infection, and probably the maturity step for replication of the HIV molecule.

Macrolide antibiotics M-4365 produced by Micromonospora. IV. Antimycoplasmal activity of antibiotic M-4365 G2 (de-epoxy rosamicin)

In vitro activities of M-4365 G2, a new basic 16-membered macrolide antibiotic, against a total 19 strains including human, bovine, porcine, rodent, avian and saprophytic mycoplasmas were compared with those of three other macrolide antibiotics, josamycin, erythromycin and tylosin. M-4365 G2 exhibited stronger activities than the other macrolide antibiotics against 11 strains of mycoplasma tested. Especially, its higher activities against M. pneumoniae Mac and FU, U. urealyticum T-960, M. mycoides PG-1 and M. gallisepticum Kp-13, PG-31 and 9-49A were to be noticed (final minimum inhibitory concentrations: 0.0001 approximately 0.049 microgram/ml). Higher antimycoplasmal activity of M-4365 G2 than that of tylosin was also proved in experimental treatment of chickens intranasally inoculated with M. gallisepticum Kp-13 by feeding a diet containing the drug. M. gallisepticum Kp-13 was not isolated from the infected chickens fed a diet containing 0.0063% or more of M-4365 G2.

Mutational biosynthesis of butirosin analogs. II. 3', 4'-Dideoxy-6'-N-methylbutirosins, new semisynthetic aminoglycosides

A pair of new butirosin analogs was isolated from the fermentation broth obtained by cultivating a neamine-negative mutant of the butirosin-producing organism Bacillus circulans in the medium supplemented with 6'-N-methylgentamine C1a. These antibiotics were characterized and elucidated as 3', 4'-dideoxy-6'-N-methylbutirosins A and B (DMB-A & DMB-B), by chemical and spectroscopic studies. DMB-A and DMB-B exhibited broad-spectrum antibacterial activities with in vitro potency similar to or slightly less than that for the butirosin A, with the exception of strains of Pseudomonas aeruginosa and Serratia marcescens against which they exhibited activities equal to or slightly greater than that for butirosin A. As expected, they exhibited stronger activities against butirosin-resistant organisms which contain acetylating enzymes AAC(6')-I and AAC(6')-IV, and phosphorylating enzyme APH(3')-II. They were also active against some of the clinical isolates resistant to butirosins, dibekacin and/or gentamicin. The acute intravenous toxicity in mice of the DMB complex (B:70 APPROXIMATELY 80%) was somewhat less than that of the butirosin A.

Mutational biosynthesis of butirosin analogs. III. 6'-N-methylbutirosins and 3', 4'-dideoxy-6'-c-methylbutirosins, new semisynthetic aminoglycosides

Two pairs of butirosin analogs were isolated from the fermentation broths obtained by cultivating a neamine-negative mutant of the butirosin-producing organism Bacillus circulans in the medium supplemented with 6'-N-methylneamine and gentamine C2, respectively. These amtibiotics were characterized as 6'-N-mentylbutirosins A and B (NMB-A & NMB-B), and 3', 4'-dideoxy-6'-C-methylbutirosins A and B (DCB-A & DCB-B), respectively, by chemical and spectroscopic studies. NMB-A and NMB-B exhibited broad-spectrum antibacterial activities with in vitro potency similar to or slightly less than that for butirosin A, but with greater activities against butirosin-resistant strain which contains acetylating enzyme AAC-(6')-I. The activities of NMB-A and NMB-B against Pseudomonas aeruginosa strains were relatively weak. DCB-B had broad-spectrum activity, and exhibited greatly improved activity against butirosin-resistant organisms which contain acetylating enzymes AAC(6')-I and AAC(6')-IV, and phosphorylating enzyme APH(3')-II. These new butirosin analogs were also active against some of the clinical isolates resistant to butirosins, dibekacin and/or gentamicin.

Biological glycosidation of macrolide aglycones. II. Isolation and characterization of desosaminyl-platenolide I

Biological glycosidation of platenolide I (I), a biosynthetic intermediate of 16-membered macrolide antibiotic platenomycin aglycones, with desosamine by Streptomycetes producing 14-membered macrolide antibiotics was attempted. Streptomyces narbonensis producing narbomycin gave a new product designated as 5-O-desosaminyl-platenolide I (III), and Streptomyces venezuelae producing narbomycin and picromycin gave III together with a second new product, 5-O-desosaminyl-14-hydroxyplatenolide I (IV). A nonantibiotic-producing blocked mutant of Streptomyces platensis subsp. malvinus, a producer of platenomycins, converted III to an antibiotically active compound identified as 3-O-propionyl-5-O-desosaminyl-9-dihydro-18-oxo-platenolide I (V).

Macrolide antibiotics M-4365 produced by Micromonospora. II. Chemical structures

By physiochemical analyses and chemical procedures, the structures of a series of basic 16-membered macrolide antibiotics, M-4365, A1, A2, A3, G1, G2 and G3 were elucidated, and it was found that M-4365 A1, G1 and G2 were novel, while M-4365 A2, A3 and G3 were identical with rosamicin, juvenimicins A4 and B1, respectively.

Biological glycosidation of macrolide aglycones. I. Isolation and characterization of 5-O-mycaminosyl narbonolide and 9-dihydro-5-O-mycaminosyl narbonolide

Glycosidation of narbonolide with mycaminose was attempted by feeding narbonolide during the fermentation of a parent or a mutant strain of Streptomyces platensis, a producer of 16-membered macrolide antibiotics, platenomycins. As a result, two new compounds I and II were isolated from the fermentation broth and identified as 5-O-mycaminosyl narbonolide (I) and 9-dihydro-5-O-mycaminosyl narbonolide (II), respectively. Physicochemical and antimicrobial properties of I and II are also referred to.

Mass spectrometry of platenolides and their derivatives in connection with structure elucidation

Mass spectra of platenolides--biosynthetic precursors of the 16-membered macrolide antibiotics, platenomycins--and their derivatives are discussed in detail especially in connection with structure elucidation. Mass spectrometry was of great use in establishing the structures for platenolides I (1) and II (2).