Antibiotic LL-E19085

Abstract

This disclosure describes novel antibacterial agents designated LL-E10985.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.gamma. and LL-E19085.zeta., having the structure: ##STR1## their production by aerobic fermentation of a new subspecies of Micromonospora citrea NRRL 18351 and mutants thereof, and the isolation and purification thereof.

Description

SUMMARY OF THE INVENTION

This invention relates to new antibacterial agents designated LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta. and LL-E19085.eta., to their production by fermentation, to methods for their recovery and concentration from crude solutions and to processes for their purification. The present invention includes within its scope the antibacterial agents in dilute form, as crude concentrates and in pure form. The effect of these new agents on specific microorganisms, together with their chemical and physical properties, differentiate them from previously described antibacterial agents. The structure of antibiotic LL-E19085 is as follows:

______________________________________ ##STR2##E19085 R1 R2______________________________________.alpha. COCH.sub.2 CH(CH.sub.3).sub.2 CH.sub.3.beta. COCH(CH.sub.3).sub.2 CH.sub.3.gamma. COCH.sub.3 CH.sub.3.zeta. COCH.sub.2 CH(CH.sub.3).sub.2 H.eta. H CH.sub.3______________________________________

The physiochemical characteristics of antibiotic LL-E19085.alpha. are as follows:

a) Molecular formula: C.sub.36 H.sub.31 NO.sub.12 ; b) Molecular weight: 669 FABMS (M+3H).sup.+ =M/Z 672.21176; c) Elemental Analysis: C, 64.55; H, 4.46; N, 1.92; d) Specific rotation: [.alpha.].sub.D.sup.26 =-52.degree. (C, 1.11%--dichloromethane); e) Ultraviolet absorption spectra: .lambda.max nm .epsilon. 0.1N HCl=224 nm (27,700), 255 nm (21,900), 328 nm (16,400), 420 nm (4,230) .lambda.max nm .epsilon. 0.1N NaOH=217 nm (76,100), 340 nm (15,100), 399 nm (12,900) .lambda.max nm .epsilon. CH.sub.3 OH=222 nm (38,200), 240 nm (30,100), 255 nm (30,100), 321 nm (24,500), 384 nm (8,050) f) infrared absorption spectrum: (KBr disk), max (cm.sup.-1) 1800, 1742, 1690, 1621, 1422, 1273; g) Proton magnetic resonance spectrum: (CDCl.sub.3) shows significant peaks as follows: ______________________________________.delta. #H M J (Hz)______________________________________13.47 1 s --8.20 1 d 8.57.92 1 d 8.57.58 1 s --7.19 1 s --7.09 1 s --4.78 1 d 11.64.45 1 d 11.64.02 3 s --3.99 3 s --3.48 1 d 12.83.35 1 d 12.82.21 2 d 6.82.10 1 m --1.83 3 s --1.80 3 s --0.955 6 d 6.48______________________________________ h) Carbon-13 nuclear magnetic resonance spectrum: (CDCl.sub.3) shows significant peaks as follows: ______________________________________.delta. M .delta. M .delta. M______________________________________181.2 s 134.8 s 65.0 t178.1 s 132.1 d 62.3 s 172.1* s 129.7 s 56.8 q171.5 s 124.4 d 56.5 q165.8 s 120.8 s 42.9 t162.1 s 119.9 s 41.9 t155.5 s 119.5 s 25.8 q153.4 s 117.7 d 25.5 d150.8 s 107.3 s 22.4 q148.7 s 104.9 d 22.3 q140.7 s 100.4 d 20.2 q137.7 s 93.4 s______________________________________ *Two superimposed resonances.

The physiochemical characteristics of antibiotic LL-E19085.beta. are as follows:

a) Molecular formula: C.sub.35 H.sub.29 NO.sub.12 ; b) Molecular weight: 655; c) Ultraviolet absorption spectra: .lambda.max (CH.sub.3 CH/0.05M pH 4.5 NH.sub.4 OAC 3/2) 258 nm, 325 nm, 385 nm; d) Infrared absorption spectra: .lambda.max (cm.sup.-1) 3434 br, 2924, 1804, 1752, 1693, 1621, 1426, 1272; e) Proton nuclear magnetic resonance spectrum: CDCl.sub.3 shows significant peaks as follows: ______________________________________.delta. #H M J (Hz)______________________________________13.50 1 br --8.26 1 d 8.57.94 1 d 8.57.66 1 s --7.21 1 s --7.14 1 s --4.77 1 d 11.64.47 1 d 11.64.04 3 s --4.02 3 s --3.50 1 d 14.83.36 1 d 14.82.55 1 septet 7.01.83 3 s --1.77 3 s --1.19 3 d 7.01.18 3 d 7.0______________________________________ f) HPCL* retention time: 2.4 minutes. *Analytical hplc system. The system consisted of a C.sub.18 reversed-phase column (2.1 mm.times.100 mm) eluted with 60% ACN 40% 0.05M pH 4.5 NH.sub.4 OAc at 0.5 ml/min. Detection was by absorbance at 325 nm.

The physiochemical characteristics of antibiotic LL-E19085.gamma. are as follows:

a) Molecular formula: C.sub.33 H.sub.25 NO.sub.12 ; b) Molecular weight: 627 c) Ultraviolet absorption spectra: .lambda.max (CH.sub.3 CN/0.05M pH 4.5 NH.sub.4 OAC 3/2) 258 nm, 325 nm, 385 nm; d) Infrared absorption spectra: .lambda.max (KBr) cm.sup.-1 : 3433 br, 2925, 1805, 1745, 1694, 1621, 1426, 1272; e) Proton nuclear magnetic resonance spectrum: CDCl.sub.3 shows significant peaks as follows: ______________________________________.delta. #H M J (Hz)______________________________________13.46 1 br --8.26 1 d 8.67.94 1 d 8.67.66 1 s --7.21 1 s --7.14 1 s --4.81 1 d 11.54.43 1 d 11.54.04 3 s --4.02 3 s --3.50 1 d 14.93.36 1 d 14.92.10 3 s --1.82 3 s --1.75 3 s --______________________________________ f) HPLC* retention time: 1.6 minutes. *Analytical hplc system. Same conditions as used in LL-E19085.beta. recited above.

The physiochemical characteristics of antibiotic LL-E19085.zeta. are as follows:

a) Molecular formula: C.sub.35 H.sub.29 NO.sub.12 ; b) Molecular weight: 655; c) Ultraviolet absorption spectra: .lambda.max (CH3CH/0.05M pH 4.5 NH.sub.4 OAC3/2): 258 nm, 324 nm, 380 nm, 420 nm; d) Infrared absorption spectrum: (KBr) .lambda.max (Cm.sup.-1) 3429 (br), 2960, 1805, 1745, 1693, 1626, 1421, 1279; e) Proton nuclear magnetic resonance spectrum: CDCl.sub.3 ______________________________________.delta. #H M J (Hz)______________________________________13.45 1 s --8.22 1 d 8.57.91 1 d 8.57.75 1 s --7.26 1 s --7.14 1 s --6.20 1 br --4.76 1 d 11.54.45 1 d 11.54.06 3 s --3.48 1 d 14.83.35 1 d 14.82.20 2 d 6.62.10 1 septet 6.61.81 3 s --1.75 3 s --.950 6 d 6.6______________________________________ f) Carbon 13 nuclear magnetic resonance spectra: ______________________________________ .delta. .delta.______________________________________ 181.4 119.7 178.0 119.6 172.8 117.7 171.7 108.4 171.6 107.1 165.6 100.2 161.6 93.4 154.7 64.9 153.5 62.3 150.2 56.5 146.3 42.8 140.5 41.7 137.5 25.6 134.6 25.4 132.2 22.2* 129.7 20.0 124.2 120.1______________________________________ *two superimposed signals g) HPLC* retention time: 1.9 minutes * Analytical hpcl system. Same conditions as in LL-E19085.beta. recited above.

The physiochemical characteristics of antibiotic LL-E19085.eta. are as follows:

a) Molecular formula: C.sub.31 H.sub.23 NO.sub.11 ; b) Molecular weight: 585 HRFABMS: (M+3H).sup.+ =M/Z 588.1479; c) Specific rotation: [.alpha.].sub.D.sup.26o =-63.degree. (C 0.19)DMSO; d) Ultra violet absorption spectrum: .lambda.max (MeOH/CH.sub.2 CL.sub.2 1:1) 223 (37,800), 321 (21,700), 302 (21,750); e) Infrared absorption spectrum: (KBr) .lambda.max CM.sup.-1 3437 (br), 2923, 1798, 1691, 1623, 1427, 1276; f) Proton nuclear magnetic resonance spectrum: (CDCl.sub.3 DMSO d.sub.6) ______________________________________.delta. #H M J (Hz)______________________________________8.24 1 d 8.57.96 1 d 8.57.63 1 s --7.23 1 s --7.17 1 s --5.28 1 br --4.33 1 brd 10.14.04 3 s --4.02 3 s --3.90 1 brd 10.13.51 1 d 14.73.37 1 d 14.71.77 3 s --1.71 3 s --______________________________________ g) Carbon 13 nuclear magnetic resonance spectrum: (CMSO D.sub.6 /CDCl.sub.3) ______________________________________ .delta. .delta.______________________________________ 180.9 107.4 177.7 104.4 173.0 100.7 171.9 93.3 165.8 65.8 161.4 63.4 155.6 56.7 153.8 56.1 150.8 41.4 148.6 25.3 140.3 19.0 137.3 135.2 132.2 129.6 123.9 120.2 119.3 119.2 117.6______________________________________ h) HPLC* retention time: 1.2 minutes * Analytical hplc system. Same conditions as in LL-E19085.beta. recited above.

DETAILED DESCRIPTION OF THE INVENTION

The antibacterial agents LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta. and LL-E19085.eta. are produced by aerobic fermentation of microbial culture LL-E19085 which is a natural selection isolate of a culture isolated from a soil sample collected in Manyara, Tanzania. The culture was taxonomically characterized and identified as a new subspecies of Micromonospora citrea.

This new subspecies is maintained in the culture collection of the Medical Research Division, American Cyanamid Company, Pearl River, N.Y. as culture number LL-E19085. A viable culture of this new microorganism has been deposited with the ARS Culture Collection, Fermentation Laboratory, Northern Regional Research Center, U.S. Department of Agriculture, 1815 North Univeristy Street, Peoria, Ill. 61604 and has been added to its permanent collection. It has been assigned the strain designation NRRL 18351 by such depository. Access to such culture, under strain designation NRRL 18351, during pendency of the instant application shall be available to one determined by the Commissioner of Patents and Trademarks to be entitled thereto under 37 C.F.R. Section 1.14 and 35 U.S.C. Section 122, and all restrictions on availability to the public of such culture will be irrevocably removed upon grant of a patent on the instant application.

Observations were made of the cultural, physiological and morphological features of culture LL-E19085 using methods well known in the art. The generic assignment of LL-E19085 to the genus Micromonospora was confirmed morphologically and chemically. The strain produced monospores on the vegetative hyphae. No aerial hyphae were observed. Electron microscopic examination showed that the spores were warty. Whole cell analysis showed that LL-E19085 contained the meso isomer as well as traces of the L isomer of diaminopimelic acid. This strain showed the presence of xylose plus traces of arabinose in its whole cell sugar hydrolysates. Therefore LL-E19085 is considered to be a subspecies of Micromonospora citrea.

Comparative data on the morphology of LL-E19085 is given in Tables I and II. Physiological data is given in Tables III and IV.

TABLE I______________________________________ISP Agar SolubleMedium Spores Vegetative Mycelium Pigments______________________________________Yeast-Malt Slight, black Strong orange (50) Slight,(ISP 2) at edge to medium orange- brown- yellow (71*) blackOatmeal None Light orange-yellow Slight,(ISP 3) (70) to vivid brownish orange-yellow (66)Inorganic None Light orange-yellow Slight,Salts-Starch (70) to vivid brownish(ISP 4) orange-yellow (66)Glycerol- Slight, Light tone of Slight,Asparagine brownish at brownish-orange brownish(ISP 5) edge (54)______________________________________ *Parenthetical numbers are colors taken from Kelly, K. L. and Judd, D. B. Color. Universal Language and Dictionary of Names, Nat. Bur. Stand. (U.S.), Spec. Publ. 440, 1976, Washington, D.C. and the accompanying InterSociety Color Council, National Bureau of Standards Centroid Color Charts. TABLE II______________________________________Agar Medium Actinomycete Growth (28.degree. C., 2 weeks)______________________________________Pablum Brown vegetative hyphae. Sparse spores. Soluble dark brown pigment.Yeast Czapek's Brownish tan vegetative hyphae. Sparse spores. Slight soluble dark-brownish pigment.Czapek's Vegetative hyphae covered/spores. Black spores. Slight dark pigment.Yeast Extract- Black spores, Dry soluble brownishDextrose pigment.Nutrient Orange-brown vegetative hyphae. Sparse black spores. Moderate brown pigment.Nutrient Glycerol Blackish-tan vegetative hyphae. Sparse spores. Intense brown-black pigment.Bennett's Dextrin Tan vegetative hyphae. Moderate black spores. Soluble reddish-brown pigment.Glucose Asparagine Orange-tan vegetative hyphae. No spores. Slight soluble dark pig- ment.______________________________________ TABLE III______________________________________ CarbohydrateCarbohydrate Utilization______________________________________Arabinose +Cellulose -Fructose .+-.Glucose +Inositol -Mannitol -Raffinose -Rhamnose -Sucrose .+-.Xylose +______________________________________ TABLE IV______________________________________ PhysiologicalGordon Test Reaction______________________________________Hydrolysis ofCasein +Xanthine -Hypoxanthine -Tyrosine +Adenine +Gelatin +Potato Starch +Esculin +PhysiologicalProduction ofNitrate Reductase -Phosphatase +Urease -Growth onSalicin -5% Sodium Chloride -Lysozyme Broth -Decarboxylation ofAcetate +Benzoate -Citrate -Lactate +Malate -Mucate -Oxalate -Propionate +Pyruvate +Succinate -Tartrate -Acid fromAdonitol -Arabinose +Cellobiose +Dextrin +Dulcitol -Erythritol -Fructose +Galactose +Glucose +GLycerol +Inositol -Lactose +Maltose +Mannitol -Mannose +.alpha.-Methyl-D-glucoside +Melibiose +Raffinose +Rhamnose -Salicin +Sorbitol -Sucrose +Trehalose +Xylose +.beta.-Methyl-D-xyloside -Growth at10.degree. C. -42.degree. C. +45.degree. C. +______________________________________ + = positive; - = negative

It is to be understood that for the production of the new antibacterial agents LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta. and LL-E19085.eta., the present invention is not limited to this particular organism or to organisms fully answering the above growth and microscopic characteristics, which are given for illustrative purposes only. In fact it is desired and intended to include the use of mutants produced from this organism by various means such as exposure to x-radiation, ultraviolet radiation, N'-methyl-N'-nitro-N-nitrosoguanidine, actinophages and the like.

The in vitro antibacterial effects of antibiotics LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta. and LL-E19085.eta. were determined by standard agar dilution methods against clinical isolates obtained from medical centers representing various geographical areas in the United States. The inoculum of each culture was approximately 1 to 5.times.10.sup.4 colony forming units applied with a Steers multiple inocula replicator to plates containing the antibiotic in Mueller-Hinton agar. The agar was supplemented with about 5% sheep blood where required for the growth of the organism. The results are given in Tables V and VI.

TABLE V______________________________________In vitro Antibacterial Activity of LL-E19085.alpha. Minimal Inhibitory ConcentrationOrganism (mcg/ml)______________________________________Staphylococcus aureus ATCC 25923 0.12Staphylococcus aureus Smith 0.12Staphylococcus aureus VGH 84-45 .ltoreq.0.06Staphylococcus aureus CMC 83-127 .ltoreq.0.06Staphylococcus aureus CMC 83-131 .ltoreq.0.06Staphylococcus aureus CMC 83-132 .ltoreq.0.06Staphylococcus aureus SSC 82-57 .ltoreq.0.06Staphylococcus epidermidis IO 83-58 .ltoreq.0.06Staphylococcus saphrophiticus VGH 84-50 .ltoreq.0.06Streptococcus .beta.-hemolyticus C 203 .ltoreq.0.06Streptococcus .beta.-hemolyticus VGH 84-60 .ltoreq.0.06Streptococcus .beta.-hemolyticus VGH 84-61 .ltoreq.0.06Streptococcus .beta.-hemolyticus VGH 84-62 .ltoreq.0.06Streptococcus pneumoniae SV-1 .ltoreq.0.06Streptococcus pneumoniae K 84-21 .ltoreq.0.06Enterococcus VGH 84-65 .ltoreq.0.06Enterococcus VGH 84-68 .ltoreq.0.06Enterococcus IO 83-28 .ltoreq.0.06Enterococcus IO 83-40 0.12Enterococcus CMC 83-72 .ltoreq.0.06Escherichia coli No. 311 >128Klebsiella pneumoniae AD >128Enterobacter cloacae VGH 84-37 >128Morganella morganii VGH 84-11 >128Serratia marcescens K 84-14 >128Pseudomonas aeruginosa 12-4-4 >128Citrobacter diversis MOR 84-3 >128Proteus vulgaris CMC 84-35 >128Alcaligenes ssp. ISG 86-34 >128erratia rubidea UHL 86-4 >128Bacteroides fragilis ATCC 25285 16Bacteroides vulgaris ATCC 29327 .ltoreq.0.06Bacteroides theta ATCC 29741 4Bacteroides theta ATCC 29742 4Clostridium perfringen ATCC 13124 .ltoreq.0.06Clostridium differensis ATCC 17858 .ltoreq.0.06Peptococcus magnus ATCC 29328 .ltoreq.0.06Peptococcus magnus ATCC 14956 .ltoreq.0.06Peptococcus asacrolytis ATCC 29743 .ltoreq.0.06Escherichia coli ATCC 25922 >128Staphylococcus aureus ATCC 29213 .ltoreq.0.06______________________________________ TABLE VI__________________________________________________________________________Invitro Antibacterial Activity of LL-E19085.beta.,.gamma.,.delta.,.eta. Minimal Inhibitory Concentration (mcg/ml)Organism LL-E19085 LL-E19085 LL-E19085 LL-E19085__________________________________________________________________________Staphylococcus aureus NEMC 87-69 4 4 8 .ltoreq..015Staphylococcus aureus ROSE (MP) 2 1 2 .ltoreq..015Staphylococcus aureus IVES 542 4 8 8 .ltoreq..015Staphylococcus hemolyticus AVAH 88-1 2 8 4 .ltoreq..015Staphylococcus hemolyticus AVAH 88-3 4 0.5 2 .ltoreq..015Bacteroides cereus DAVIES 2 0.5 2 .ltoreq..015Streptococcus faecalis ARUM 87-41 2 0.5 2 .ltoreq..015Enterococcus CHBM 88-60 2 0.5 2 .ltoreq..015Enterococcus Grp D WRVA 88-33 2 0.5 2 .ltoreq..015Streptococcus faecalis VCI 85-30 2 .06 2 .ltoreq..015Streptococcus faecalis VCH 84-69 2 .03 2 .ltoreq..015Streptococcus faecalis CMC 83-120 2 1 2 .ltoreq..015Streptococcus a-hemolyticus AMCH 88-84 0.5 .ltoreq..008 1 .ltoreq..015Streptococcus b-hemolyticus AMCH 88-86 2 .ltoreq..008 2 .ltoreq..015Streptococcus pneumoniae CHBM 88-70 .25 .ltoreq..008 .12 .ltoreq..015Streptococcus pneumoniae CHBB 88-75 .12 .ltoreq..008 .12 .ltoreq..015Streptococcus pneumoniae TEX 85-2 .12 .ltoreq..008 .12 .ltoreq..015Staphylococcus aureus ATCC 29213 2 1 2 .ltoreq..015Klebsiella pneumoniae NEMC 87-271 .gtoreq.64 .gtoreq.16 .gtoreq.32 .gtoreq.32Escherichia coli D21 .gtoreq.64 .gtoreq.16 .gtoreq.32 .gtoreq.32Escherichia coli D22 8 16 32 2Escherichia coli ATCC 25922 >64 >16 >32 >32Escherichia coli ATCC 35218 >64 >16 >32 >32Staphylococcus aureus ATCC 25923 0.5 .gtoreq.0.008 1 .ltoreq.0.015Staphylococcus aureus VGH 84-47 4 1 4 .ltoreq.0.015Staphylococcus aureus K82-26 2 .ltoreq.0.008 2 .ltoreq.0.015Staphylococcus aureus CMC 83-131 4 16 8 0.12__________________________________________________________________________

When the compounds are employed for the above utility, they may be combined with one or more pharmaceutically acceptable carriers, for example solvents, diluents and the like, and may be administered parenterally in the form of sterile injectable solutions or suspensions containing from about 0.05 to 5% suspending agent in an isotonic medium. Such pharmaceutical preparations may contain, for example, from about 0.05 up to about 90% of the active ingredient in combination with the carrier, more usually between about 5% and 60% by weight.

The effective dosage of active ingredient employed may vary depending on the particular compound employed, the mode of administration and the severity of the condition being treated. However, in general, satisfactory results are obtained when the compounds of the invention are administered at a daily dosage of from about 2 to about 100 mg/kg of animal body weight, preferably given in divided doses two to four times a day, or in substained release form. For most large mammals the total daily dosage is from about 100 to 750 mg, preferably from about 100 to 500 mg. Dosage forms suitable for internal use comprise from about 100 to 750 mg of the active compound in intimate admixture with liquid pharmaceutically acceptable carrier. This dosage regimen may be adjusted to provide the optimal therapeutic response, for example, several divided doses may be administered daily or the dose may be proportionally reduced as indicated by the exigencies of the therapeutic situation.

These active compounds may be administered by intravenous, intramuscular, or subcutaneous routes. Liquid carriers include sterile water, polyethylene glycols, non-ionic surfactants and edible oils such as corn, peanut and sesame oils, as are appropriate to the nature of the active ingredient and the particular form of administration desired. Adjuvants customarily employed in the preparation of pharmaceutical compositions may be advantageously included, such as preserving agents, and antioxidants, for example, vitamin E, ascorbic acid, BHT and BHA.

The pharmaceutical forms suitable for injectable use include sterile aqueous solutions or dispersions and sterile powders for the extemporaneous preparation of sterile injectable solutions or dispersions. In all cases, the form must be sterile and must be fluid to the extent that easy syringability exists. It must be stable under the conditions of manufacture and storage and must be preserved against the contaminating action of microorganisms such as bacteria and fungi. The carrier can be a solvent or dispersion medium containing, for example, water, ethanol, polyol (e.g. glycerol, propylene glycol and liquid polyethylene glycol), suitable mixtures thereof, and vegetable oils.

GENERAL FERMENTATION CONDITIONS

Cultivation of Micromonospora citrea sp. LL-E19085 may be carried out in a wide variety of liquid culture media. Media which are useful for the production of antibiotic LL-E19085.alpha. include an assimilable source of carbon, such as starch, sugar, molasses, glycerol, etc.; an assimilable source of nitrogen, such as protein, protein hydrolysate, polypeptides, amino acids, cornsteep liquor, etc.; and inorganic anions and cations, such as potassium, sodium, ammonium, calcium, sulfate, carbonate, phosphate, chloride, etc. Trace elements such as boron, molybdenum, copper, etc., are supplied as impurities of other constituents of the medium. Aeration is supplied by forcing sterile air through or onto the surface of the fermenting medium. Agitation is provided by a mechanical impeller. An antifoam agent may be added as needed. The growth of the organism is usually conducted at about 24.degree.-37.degree. C., preferably at about 28.degree. C.

The following examples describe the invention in detail.

EXAMPLE 1

Inoculum Preparation

A typical medium used to grow the inocula was prepared according to the following formula:

Dextrose: 1.0% Dextrin: 2.0% Yeast extract: 0.5% NZ Amine A *: 0.5% Calcium carbonate: 0.1% Defoam agent: 0.3% Water qs: 100% A pancreatic digest of casein, registered trademark of Sheffield Chemical, Norwich, N.Y.

This medium was sterilized and a 100 ml portion in a 500 ml flask was inoculated with mycelial scrapings from an agar slant of the culture Micromonospora citrea sp LL-E19085. The inoculated flask was then placed on a rotary shaker and agitated vigorously for approximately 48 hours at 32.degree. C., providing primary inoculum.

A 100 ml portion of this primary inoculum was then used to inoculate 10 liters of the above sterile medium which was incubated at 32.degree. C. with aeration for 72 hours, providing secondary inoculum.

A 10 liter portion of this secondary inoculum was then used to inoculate 260 liters of the above sterile medium in a tank. This medium was incubated at 32.degree. C. with agitation by an impeller driven at 180 rpm, a sterile air flow of 200 liters per minute and the addition of 50 ml of a defoaming agent for about 48 hours, providing tertiary inoculum.

EXAMPLE 2

Fermentation

A fermentation medium was prepared according to the following formulation:

Dextrin: 3.0% Dextrose: 0.5% Nutrisoy: 1.5% Corn steep liquor: 0.5% Calcium carbonate: 0.5% Defoam agent: 0.3% Water qs: 100%

A 2800 liter portion of the above medium in a tank was sterilized and then inoculated with 300 liters of tertiary inoculum prepared as described in Example 1. Aeration was supplied at the rate of 6.5 liters of sterile air per liter of mash per minute and agitation was supplied by an impeller driven at about 110 rpm. The temperature was maintained at 28.degree. C. and defoaming agent was added as required. The fermentation was terminated after 129 hours.

EXAMPLE 1

Isolation of Antibiotic LL-E19085.alpha.

A 1500 liter portion of the whole harvest mash, prepared as described in Example 2, was mixed with 15 liters of toluene for 30 minutes, then 250 lb of diatomaceous earth was added. After mixing for 15 minutes this mixture was filtered and the cake washed with 150 liters of water. The cake was slurried in a mixture of 208 liters of acetone, 416 liters of dichloromethane and 20 liters of 1.5N hydrochloric acid for 2 hours and then filtered. The cake was washed with about 175 liters of dichloromethane with the wash and filtrate combined. The cake was then washed with about 800 liters of water and this wash also combined with the above wash and filtrate and mixed. The dichloromethane layer was separated and washed with an equal volume of water. The dichloromethane layer was separated and concentrated to 100 liters, reextracted with fresh methylene chloride if any aqueous phase was present, and finally concentrated to about 1-3 liters.

The dichloromethane extracts were triturated repeatedly, first with hexane:dichloromethane (9:1) and then with hexane alone to remove the bulk of the fatty impurities giving a brown powder.

Several such partially purified preparations, from fermentations conducted as described in Example 2, totaling 20 g and averaging 10-30% LL-E19085.alpha., were combined and purified by reverse-phase chromatography. The column consisted of a 15 liter bed of C.sub.18 bonded phase packing of 40 micron particle size. The charge was loaded onto the column in 500 ml of acetonitrile:tetrahydrofuran (1:1). The column was developed at a flow rate of 1.0 liter per minute with a mobile phase consisting of acetonitrile:0.1M pH 4.5 ammonium acetate buffer (8.2). Fractions were collected at approximately 12 minute intervals. Fractions 6 and 7 were combined and evaporated, giving 2.7 g of pure LL-E19085.alpha. having the characteristics disclosed in the hereinabove specification.

EXAMPLE 4

Isolation of Antibiotics LL-E19085.beta. and LL-E19085.gamma.

These minor components were isolated from various side fractions derived from the refining of LL-E19085.alpha. from tank fermentations. Chromatography of the material from methylene chloride (CH.sub.2 Cl.sub.2), extraction of the whole mash on silica gel, and eluting with mixtures of acetone in CH.sub.2 Cl.sub.2 yielded a fraction enriched in .beta. and .gamma.. This material was dissolved in acetonitrile (ACN) and separated by reversed phase chromatography, NB 7411C99. The column was 21.4 mm.times.25 mm packed with C.sub.18 bonded silica. The column was eluted with 60% ACN, 40% 0.05M pH 4.5 NH.sub.4 OAc. Fractions were combined on the basis of analytical hplc to yield .beta. and .gamma..

EXAMPLE 5

Isolation of Antibiotic LL-E19085.eta.

An early fraction from he large-scale C.sub.18 column used to purify E19085.alpha. was used to obtain the .eta. component. The material was dissolved in ACN and separated on the 21.4 mm.times.25 cm C.sub.18 column eluting with 50% ACN, 50% 0.05M pH 4.5 NH.sub.4 OAc. Fractions were combined on the basis of analytical hplc to yield E19085.eta..

EXAMPLE 6

Isolation of LL-E19085.zeta.

Side fractions from silica gel purification of E19085.alpha. were enriched in E19085.zeta. (NB7411C73). The fraction containing zeta was rechromatographed on silica gel (150 g Wolen, column 2.5.times.50 cm) eluted with Ch.sub.2 Cl.sub.2 followed by 5% acetone 95% CH.sub.2 Cl.sub.2. Fractions were combined on the basis of analytical hplc and evaporated to dryness to yield E19085.zeta.. (7580C151)

Claims

1. The antibiotic LL-E19085.alpha., an antibacterial agent, of the formula: ##STR3## wherein R.sub.1 is COCH.sub.2 CH(CH.sub.3).sub.2 and R.sub.2 is CH.sub.3.

2. The antibiotic LL-E19085.beta. of the formula: ##STR4## wherein R.sub.1 is COCH(CH.sub.3).sub.2 and R.sub.2 is CH.sub.3.

3. The antibiotic LL-E19085.gamma., of the formula: ##STR5## wherein R.sub.1 is COCH.sub.3 and R.sub.2 is CH.sub.3.

4. The antibiotic LL-E19085.zeta.of the formula: ##STR6## wherein R.sub.1 is COCH.sub.2 CH(CH.sub.3).sub.2 and R.sub.2 is H.

5. The antibiotic LL-E19085.eta. of the formula: ##STR7## wherein R.sub.1 is H and R.sub.2 is CH.sub.3.

6. A pharmaceutical composition comprising an antibacterially effective amount of a compound of any one of claims 1, 2, 3, 4 or 5 in association with a pharmaceutically acceptable carrier.

7. A method of treating bacterial infections in warm-blooded animals which comprises administering to said animals an antibacterially effective amount of a compound selected from the group consisting of LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta., and LL-E19085.eta..

8. A process for producing an antibiotic selected from the group consisting of LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta., and LL-E19085.eta. which comprises aerobically fermenting the microorganism Micromonospora citrea sp. NRRL 18351 or mutants thereof which produce said antibiotic in a liquid medium containing assimilable sources of carbon, nitrogen and inorganic salts, until substantial antibiotic activity is imparted to said medium and then recovering said antibiotic therefrom.

9. The process for producing antibiotics LL-E19085.alpha., LL-E19085.beta., LL-E19085.gamma., LL-E19085.zeta., and LL-E19085.eta. as recited in claim 8, which comprises aerobically fermenting a liquid medium containing assimilable sources of carbon, nitrogen and inorganic salts, which medium has been inoculated with a viable culture of the microorganism Micromonospora citrea sp. NRRL 18351 or mutants thereof, which produce said antibiotic maintaining said fermentation culture at a temperature of about 24.degree.-37.degree. C. for a period of 50-150 hours, harvesting the mash and extracting said antibiotic.