Cyclipostins: novel hormone-sensitive lipase inhibitors from Streptomyces sp. DSM 13381. I. Taxonomic studies of the producer microorganism and fermentation results.

The cyclipostins are a group of hormone-sensitive lipase inhibitors produced by a Streptomyces species. Having verticillate spore chains this strain exhibits significant differences to the known species of the former genus Streptoverticillium. Taxonomic studies and fermentation results are presented.

Pluraflavins, potent antitumor antibiotics from Saccharothrix sp. DSM 12931.

The new pluramycin-type antibiotics pluraflavin A, C43H54N2O14, pluraflavin B, C43H56N2O15, and pluraflavin E, C36H41NO14 were isolated from cultures of the Saccharothrix species DSM 12931. The structures of the novel compounds were elucidated with the aid of 2D NMR and mass spectrometric investigations. The characteristic structural element of pluraflavins A and B is an additional 4-epi-vancosamine unit at position 13 of the anthraquinone-gamma-pyrone ring system. Pluraflavin E has a carboxyl group in this position. Pluraflavin A has a reactive dimethyl epoxide side chain at position 2 of the anthraquinone-gamma-pyrone aglycon, which may explain the high activity of the antibiotic. The outstanding biological characteristic of pluraflavin A is its powerful, organ-dependent cytostatic action: the IC50 in the colon carcinoma proliferation assay is in the subnanomolar range.

Cephaibols, new peptaibol antibiotics with anthelmintic properties from Acremonium tubakii DSM 12774.

Two groups of new peptaibol-type antibiotics termed cephaibols have been isolated from the fungus Acremonium tubakii, DSM 12774. These 16- or 17-unit straight-chain peptides, whose structures were characterized by amino acid analyses, 2-D NMR experiments, and by mass spectrometric sequencing, have a high content of the unusual amino acids aminoisobutyric acid and isovaline. The principal constituent of the novel peptaibol mixture is cephaibol A, which is formed in abundance in cultures of the wild strain. The striking biological property of cephaibol A is its pronounced anthelmintic action and activity against ectoparasites.

Friulimicins: novel lipopeptide antibiotics with peptidoglycan synthesis inhibiting activity from Actinoplanes friuliensis sp. nov. I. Taxonomic studies of the producing microorganism and fermentation.

A strain that produces new lipopeptide antibiotics is a new species of the genus Actinoplanes for which we propose the name Actinoplanes friuliensis (type strain: HAG 010964). The strain is an actinoplanete actinomycete having cell wall II composition and forming sporangia. Comparisons with Actinoplanes spp. which have similarities with our isolate, including fatty acid analysis, showed that the isolate belongs to a new species. Taxonomic studies and fermentation are presented.

Friulimicins: novel lipopeptide antibiotics with peptidoglycan synthesis inhibiting activity from Actinoplanes friuliensis sp. nov. II. Isolation and structural characterization.

Four novel lipopeptide antibiotics, friulimicins A, B, C, and D, were isolated from cultures of Actinoplanes friuliensis HAG 010964 after fermentation in different nutrient media. The new compounds were separated by ion-exchange chromatography from the acidic lipopeptides of the amphomycin type also present in the culture fluid, compounds A-1437 A, B, E, and G. The principal constituent friulimicin B, C59H94N14O19, was structurally characterized by mass spectrometric investigations of its hydrolysis and partial degradation products and by sequencing of the cyclic acyl peptide. The NMR data of friulimycin B and the amphomycin constituent A-1437 B were completely assigned by a variety of 2-D experiments, and confirmed the structures determined by mass spectrometry. All 8 lipopeptides possess an identical peptide macrocycle as their central element, linked via a diaminobutyric acid N-terminal either to an acylated asparagine residue or, in the case of the amphomycin series, to an acylated aspartic acid residue. The structures of the amphomycins have now been revised to take account of the peptide framework described herein and the determined cis-configuration of the exocyclic double bond. As a consequence of their higher isoelectric points, the new compounds friulimicin A, B, C, and D have different properties than the amphomycins.

Effect of PGG-glucan on the rate of serious postoperative infection or death observed after high-risk gastrointestinal operations. Betafectin Gastrointestinal Study Group.

BACKGROUND: Postoperative infections remain common after high-risk gastrointestinal procedures. PGG-glucan (Betafectin; Alpha Beta Technology Inc, Worcester, Mass), derived from yeast cell walls, promotes phagocytosis and intracellular killing of bacterial pathogens by leukocytes, prevents infection in an animal model of wound infection, and acts synergistically with antibiotics to reduce mortality in rat peritonitis. HYPOTHESIS: We hypothesized that infectious complications in these patients might be reduced by the administration of a nonspecific immune-enhancing agent. DESIGN: Multicenter, prospective, randomized, double-blind, placebo-controlled trial of 1249 patients prospectively stratified into colorectal or noncolorectal strata. SETTING: Thirty-nine medical centers throughout the United States. PATIENTS: Aged 18 years or older, scheduled for gastrointestinal procedure lasting 2 to 8 hours, with 2 or more defined risk factors. INTERVENTIONS: PGG-glucan, 0.5 mg/kg or 1.0 mg/kg, or placebo once preoperatively and 3 times postoperatively. All patients received standardized antibiotic prophylaxis. MAIN OUTCOME MEASURES: Serious infection or death within 30 days. RESULTS: All randomized patients revealed no difference in serious infections and deaths in the treated groups compared with placebo groups (15% vs 14%, P>.90). In the prospectively defined noncolorectal stratum (n = 391), PGG-glucan administration was associated with a statistically significant relative reduction (39%) in serious infections and death (placebo, 46 [36%] of 129 vs either PGG-glucan group, 29 [21%] of 132 and 28 [22%] of 130, P<.02). PGG-glucan reduced postoperative infection or death in malnourished patients having noncolorectal procedures (31 [44%] of 70, placebo group; 16 [24%] of 68, 0.5-mg/kg PGG-glucan group; 12 [17%] of 72, 1.0-mg/kg PGG-glucan group; P<.001). Study drug was stopped owing to adverse effects more frequently for patients receiving PGG-glucan than placebo (2%, 4%, and 7% for the placebo group, 0.5-mg/kg PGG-glucan group, and 1.0-mg/kg PGG-glucan group, respectively, P<.003). CONCLUSION: Perioperative administration of PGG-glucan reduced serious postoperative infections or death by 39% after high-risk noncolorectal operations.

In vitro susceptibilities of Bordetella pertussis and Bordetella parapertussis to four fluoroquinolones (levofloxacin, d-ofloxacin, ofloxacin, and ciprofloxacin), cefpirome, and meropenem.

The in vitro activities of levofloxacin, ofloxacin, d-ofloxacin, ciprofloxacin, cefpirome, and meropenem against 34 clinical isolates each of Bordetella pertussis and Bordetella parapertussis were determined by agar dilution on Mueller-Hinton agar supplemented with 5% horse blood. Levofloxacin was as active as ciprofloxacin against both species (MIC, 0.06 microgram/ml) and more active than ofloxacin and d-ofloxacin. Cefpirome was more active against B. pertussis (MIC, 1.0 microgram/ml) than against B. parapertussis (MIC, > 2 micrograms/ml), while the reverse was true for meropenem (MIC, 2.0 micrograms/ml against B. pertussis and 1.0 microgram/ml against B. parapertussis).

Antibacterial activity of RU44790, a new N-tetrazolyl monocyclic beta-lactam.

RU44790 belongs to a new class of synthetic monocyclic beta-lactam antibiotics which feature a bioisosteric tetrazole moiety instead of the more classical acidic functions at the N-1 position of the beta-lactam ring. Its antibacterial activity was evaluated against some 900 strains and was compared with those of other recent beta-lactam derivatives, especially aztreonam. RU44790 is endowed with potent activity against gram-negative bacteria. At less than or equal to 0.6 micrograms/ml, RU44790 inhibited 90% of all strains of the family Enterobacteriaceae with the exception of Citrobacter spp. (MIC for 90% of strains tested, 1.2 micrograms/ml). The activity was similar to that of aztreonam against strains that are normally susceptible to expanded-spectrum cephalosporins. On the other hand, the new compound was 10 to 100 times more potent than aztreonam and most of the other antibiotics tested against enterobacteria that produce chromosome-encoded or plasmid-mediated extended-spectrum beta-lactamases. Pseudomonas aeruginosa isolates were equally susceptible to both monobactams. RU44790 was inactive against staphylococci and had only marginal activity against streptococci (MIC for 50% of strains tested, 2.5 micrograms/ml). RU44790 was highly resistant to hydrolysis by various beta-lactamases, particularly cephalosporinases such as P99. The latter enzyme was also inhibited by the compound. RU44790 showed a high affinity for penicillin-binding protein 3 of Escherichia coli. The results suggest that RU44790 has good potential in the treatment of infections caused by gram-negative microorganisms.

Mersacidin, a new antibiotic from Bacillus. In vitro and in vivo antibacterial activity.

Mersacidin is a new peptide antibiotic of the proposed lantibiotic family. It is active in vitro and in vivo against Gram-positive bacteria including the methicillin-resistant Staphylococci. Its in vitro activity is less than those of vancomycin and erythromycin but it shows much higher activity in the in vivo system than can be expected from the in vitro testing results. A water soluble potassium salt has been prepared which has an activity profile similar to that of mersacidin, but has better in vivo activity against Streptococcus pyogenes than the parent compound.

RU 29 246, the active compound of the cephalosporin prodrug-ester HR 916. III. Pharmacokinetic properties and antibacterial activity in vivo.

The pharmacokinetics of the broad spectrum cephem RU 29 246 and its prodrug-ester HR 916 B were investigated in mice, rats and dogs and compared to those of cefpodoxime proxetil, cefuroxime axetil and cefixime. HR 916 B is well absorbed following oral administration and efficiently converted to the antibacterially active form. In mice, mean peak blood levels of 31.1 micrograms/ml of the parent compound were recorded within 20 minutes after oral administration of a single dose equivalent to 40 mg/kg RU 29 246. The bioavailability calculated on the basis of the areas under the concentration-time curves (AUC) and the urinary recoveries was about 90%. In rats, peak blood levels of 14.5 micrograms/ml were obtained 1 hour after an oral 20 mg/kg dose. The bioavailability was calculated as 70%. In dogs, 40% of an oral 10 mg/kg dose was recovered in the urine within 24 hours. Cmax was 15.9 micrograms/ml at 4.6 hours. Mean elimination half-lives of RU 29 246 were 0.35, 0.5 and 2.1 hours in mice, rats and dogs, respectively. After an oral HR 916 B dose equivalent to 50 mg/kg of RU 29 246, tissue concentrations at 0.5 hour ranged between 0.8 micrograms/g in brain and 95.7 micrograms/g in murine kidneys. These values of HR 916 B are similar to, or distinctly higher than, those of the reference compounds. Of the oral cephalosporins tested, HR 916 B had the most balanced antibacterial spectrum. With ED50s of between 0.9 and 11.5 mg/kg against staphylococci, its activity was similar to that of the additional reference compound cefaclor and higher than that of cefuroxime. Cefixime and cefpodoxime proxetil displayed low antistaphylococcal activity or were inactive. In septicemias with Enterobacteriaceae, cefixime and cefpodoxime proxetil were more potent than HR 916 B and cefaclor. Cefuroxime axetil was inactive against most of these infections. HR 916 B was also highly effective against murine lung infections caused by Klebsiella pneumoniae DT-S or Streptococcus pneumoniae 1147.

Antibacterial activity in vitro of cefpirome against clinical isolates causing sexually transmitted diseases.

The in-vitro activity of cefpirome was compared with other antibiotics against organisms causing sexually transmitted diseases (STD). The excellent activity of cefpirome against Neisseria gonorrhoeae (MIC90 1.0 mg/L), Haemophilus ducreyi (MIC90 0.5 mg/L), and Gardnerella vaginalis (MIC90 1.0 mg/L) suggests that this agent might be useful in the empirical treatment of a variety of venereal diseases.

Pharmacokinetics of cefpirome administered intravenously or intramuscularly to rats and dogs.

The pharmacokinetic profile of cefpirome was evaluated in rats and dogs after a single intravenous or intramuscular dose. A two-compartment open model was used for the calculation of the pharmacokinetic parameters for both routes of administration. The elimination half-lives after intravenous and intramuscular administration of 20 mg/kg cefpirome did not differ significantly and ranged from 0.4 h in rats to 1.1 h in dogs. Cefpirome was mainly excreted via the kidneys. After iv or im dosing of the compound, between 80% (dogs) and 90% (rats) was recovered in urine within 24 h. The bioavailability of cefpirome in rats and dogs after both routes of administration was almost identical when calculated either by the AUC or the urinary recovery rates.

The in-vitro antibacterial activity of a combination of cefpirome or cefoperazone with vancomycin against enterococci and Staphylococcus aureus.

Cefpirome, cefoperazone and ceftazidime were tested for their in-vitro activity against Enterococcus faecalis and methicillin-resistant Staphylococcus aureus (MRSA) isolates. Cefpirome was the most active cephalosporin followed by cefoperazone. Ceftazidime had only very limited activity against these strains. In experiments with cefpirome/vancomycin and cefoperazone/vancomycin combinations, synergy was detected against most MRSA strains and some enterococci. Antagonism did not occur.

In-vitro activity of cefpirome against isolates from patients with urinary tract, lower respiratory tract and wound infections.

The in-vitro activity of cefpirome, a new injectable cephalosporin, was compared with that of several other antibiotics against bacterial isolates from hospitalized patients with lower respiratory tract infections, urinary tract infections and wound infections. Minimum inhibitory concentrations were determined for 874 strains against 16 antibiotics using a microtitration technique. Cefpirome showed a very broad spectrum of activity against most pathogens tested. The spectrum included organisms such as Staphylococcus spp., enterococci, Enterobacter spp., and Pseudomonas spp. which are frequently resistant to third generation cephalosporins.

RU 29 246, the active compound of the cephalosporin-prodrug-ester HR 916. I. Antibacterial activity in vitro.

The aminothiazolyl-cephalosporin RU 29 246 is the active metabolite of the prodrug-pivaloyl-oxyethyl-ester HR 916. RU 29 246 in vitro activity includes a wide range of clinically relevant bacterial pathogens. Against methicillin-sensitive Staphylococci RU 29 246 (MIC90 of 0.25 approximately 2 micrograms/ml) was clearly more active than cefaclor, cefuroxime, cefpodoxime, cefixime and ceftibuten, but slightly less active than cefdinir. RU 29 246 inhibited hemolytic Streptococci of the serogroups A, B, C and G as well as penicillin-sensitive Streptococcus pneumoniae at concentrations similar to cefdinir, cefpodoxime and cefuroxime (MIC90 less than or equal to 0.13 micrograms/ml), but less than the other oral cephalosporins investigated (cefixime, cefaclor and ceftibuten). MIC90s of RU 29 246 against Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Salmonella spp., Shigella spp., Proteus mirabilis and Haemophilus influenzae were less than or equal to 0.5 micrograms/ml. Only RU 29 246 and cefdinir demonstrated moderate activity against Acinetobacter baumannii (MIC90 greater than or equal to 4 micrograms/ml). Most strains of Pseudomonas spp., Serratia marcescens, Enterobacter spp., Hafnia alvei and Bacteroides spp. were resistant to RU 29 246. RU 29 246 killed Escherichia coli and Staphylococcus aureus at a rate of 99% to 99.9% at concentrations of two times MIC. The pH value of the medium (range 5.5 to 8.5) and the inoculum size (range 10(5) to 10(7) cfu/ml) had no or only low influence on the antibacterial activity of RU 29 246. RU 29 246 is a broad spectrum cephalosporin including in its activity both Gram-positive and Gram-negative pathogens and therefore--depending on the bioavailability of its prodrug--looks promising as to its therapeutic perspective.

RU 29 246, the active compound of the cephalosporin-prodrug-ester HR 916. II. Stability to beta-lactamases and affinity for penicillin-binding proteins.

The aminothiazolyl-cephalosporin RU 29 246, the active metabolite of the prodrug-ester HR 916, is active against strains producing the widespread plasmid-encoded TEM-1, TEM-2 and SHV-1 beta-lactamases. Except for TEM-7 the activity of RU 29 246 against strains producing extended broad spectrum beta-lactamases (TEM-3, TEM-5, TEM-6, SHV-2, SHV-4, SHV-5, CMY-1, CTX-M), however, is low. Relative hydrolysis rates of RU 29 246 are comparable with those of cefpodoxime, the active metabolite of CS-807, and are extremely low for the TEM-1 and SHV-1 beta-lactamases. The compound demonstrates remarkable inhibitory activity against the chromosomal beta-lactamase of Enterobacter cloacae P99. In the presence of 1.7 microM this enzyme loses 50% of its activity. At concentrations of 0.43, 0.003 and 0.01 micrograms/ml the compound binds preferentially to the penicillin-binding protein (PBP) 3 of Escherichia coli K12, to the PBPs 2x and 3 of Streptococcus pneumoniae R6 and to PBP 1 of Staphylococcus aureus SG 511, respectively.

Secondary metabolites by chemical screening. 17. Nigericinol derivatives: synthesis, biological activities, and modeling studies.

The synthesis and the biological activity of C-1-reduced nigericin derivatives (nigericinols) are described and discussed. The dichloronigericinol 7 impressively demonstrated that the C-1 carboxylic acid moiety was not required for a distinct activity against bacteria and viruses. Based on the correlation between K+/H+ antiport activities and antibacterial activities it was deduced that the mode of action of the described nigericinols are related to their ionophoric properties. Molecular modeling studies showed that the efficiency of the nigericinols as ionophores correlates, qualitatively, with the probability of forming a cyclic structure, with the exception of 7.

Antibacterial activities in vitro and in vivo and pharmacokinetics of cefquinome (HR 111V), a new broad-spectrum cephalosporin.

Cefquinome is a new injectable aminothiazolyl cephalosporin derivative. It is stable against chromosomally and plasmid-encoded beta-lactamases and has a broad antibacterial spectrum. Staphylococcus aureus, streptococci, Pseudomonas aeruginosa, and members of the family Enterobacteriaceae (Escherichia coli, Salmonella spp., Klebsiella spp., Enterobacter spp., Citrobacter spp., and Serratia marcescens) are inhibited at low concentrations. Cefquinome is also active against many strains of methicillin-resistant staphylococci and enterococci. Its in vitro activity against gram-negative anaerobes is very limited. The high in vitro activity of cefquinome is reflected by its high in vivo efficacy against experimental septicemia due to different gram-positive and gram-negative bacteria. We studied the pharmacokinetic properties of cefquinome in mice, dogs, pigs, and calves. After single parenteral administrations, cefquinome displayed high peak levels, declining with half-lives of about 0.5, 0.9, 1.2, and 1.3 h, respectively. The areas under the concentration-time curve determined for dogs and mice showed linear correlations to the given doses. In dogs the urinary recovery was more than 70% within 24 h of dosing.

Secondary metabolites by chemical screening. 7. I. Elaiophylin derivatives and their biological activities.

The synthesis and the biological activity of 34 acyl derivatives of elaiophylin (1) and 6 deglycosidation products were described. Especially the unsymmetric deglycosidation products 33, 38 and 40 and dimethyloctahydroelaiophylin (21) exhibited an activity against nematodes.