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At least 19 recordsLinked to original sources
PubMed1990

Selection of Streptomyces ambofaciens mutants that produce large quantities of spiramycin and determination of optimal conditions for spiramycin production.

The aim of this work was to develop a strategy to isolate a morphologically stable mutant of Streptomyces ambofaciens ATCC 15154 which produced high titers of spiramycin. The rationale was to grow a nitrosoguanidine-mutated population for many generations under nonselective conditions followed by two cycles of protoplast formation and regeneration. A total of 2,400 surviving colonies were then screened for spiramycin production and subsequently checked for stability. From this experiment, strain 6-37 was isolated that produced 181 mg of spiramycin per liter and only one morphological type. The parent strain (ATCC 15154) produced 107 mg of spiramycin per liter and four morphological types. Strain 6-37 was then mutated with nitrosoguanidine, and 14,000 colonies were screened for spiramycin production. From this experiment, five strains were isolated that produced titers ranging from 187 to 373 mg of spiramycin per liter. Subsequent media and time studies with these strains resulted in a fermentation that produced 1,728 mg of spiramycin per liter.

Biotechnology↗
PubMed1978

Evaluation of spiramycin as a therapeutic agent for elimination of nasopharyngeal pathogens. Possible use of spiramycin for middle ear infections and for gonococcal and meningococcal nasopharyngeal carriage.

Varying doses of spiramycin were administered orally to healthy volunteers, and concentrations in serum and saliva were determined. The absorption of the drug was not significantly influenced by concomitant food intake. Saliva peak concentrations were 1.3--4.8 times higher than peak concentrations in serum. The elimination half life was 2--3 h in serum, and 4--8 h in saliva. Accumulation of the drug was seen in saliva but not in serum. The possible effect of spiramycin in eliminating bacteria from the nasopharynx was evaluated in vitro by comparing the spiramycin saliva concentrations with the MICs of bacteria known to establish themselves in the nasopharynx. At a concentration of 1.2 microgram/ml, spiramycin inhibited all investigated strains of group A streptococci, pneumococci and Branhamella catarrhalis, and at 2.4 microgram/ml all investigated gonococci. Concentrations of 19 and 38 microgram/ml, respectively, were required to inhibit all meningococci and Haemophilus influenzae. Following administration of 1.5 g spiramycin as a single daily dose for 3 days, the mean concentration in saliva reached or surpassed the MIC values of streptococci, pneumococci and Branhamella for 45 h, and of gonococci for 25 h. The possible use of spiramycin for prevention of relapses in acute otitis media and in treatment of serous otitis media is discussed, as well as the possible use of the drug in gonococcal and meningococcal nasopharyngeal carriage.

Acute Disease↗
PubMed1990

Cloning of spiramycin biosynthetic genes and their use in constructing Streptomyces ambofaciens mutants defective in spiramycin biosynthesis.

Several cosmid clones from Streptomyces ambofaciens containing the spiramycin resistance gene srmB were introduced into S. fradiae PM73, a mutant defective in tylosin synthesis, resulting in tylosin synthesis. The DNA responsible for this complementation was localized to a 10.5-kilobase EcoRI fragment. A 32-kilobase DNA segment which included the srmB spiramycin resistance gene and DNA which complemented the defect in strain PM73 were mutagenized in vivo with Tn10 carrying the gene for Nmr (which is expressed in Streptomyces spp.) or in vitro by insertional mutagenesis with a drug resistance gene (Nmr) cassette. When these mutagenized DNA segments were crossed into the S. ambofaciens chromosome, three mutant classes blocked in spiramycin synthesis were obtained. One mutant accumulated two precursors of spiramycin, platenolide I and platenolide II. Two mutants, when cofermented with the platenolide-accumulating mutant, produced spiramycin. Tylactone supplementation of these two mutants resulted in the synthesis of a group of compounds exhibiting antibiotic activity. Two other mutants failed to coferment with any of the other mutants or to respond to tylactone supplementation.

Chromosomes, Bacterial↗
PubMed1986

[Curative activity of spiramycin adipate by parenteral route in experimental septicemia in mice. Comparison with orally administered basic spiramycin].

Experimental septicemia was induced in mice by intraperitoneal injection of 10 to 100 lethal doses of Staphylococcus aureus and Streptococcus pneumoniae. Animals were treated by a mixture of adipic acid and spiramycin (subcutaneous route) or by spiramycin base (oral route), 1 and 6 hours after infection. To determine the effective dose 50% that achieves survival of half the mice after 7 days, each drug was used in 6 dosages (mg/kg) and each dosage was given to 12 mice. In 21 independent experiments, ED50S of spiramycin adipate by the subcutaneous route were found to be 5 to 50 times lower than those of spiramycin base per os. These results are consistent with the high serum peak concentrations of spiramycin adipate observed following subcutaneous administration.

Adipates↗
PubMed1984

Chemical modification of spiramycins. III. Synthesis and antibacterial activities of 4''-sulfonates and 4''-alkylethers of spiramycin I.

Among the derivatives protected with t-butyldimethylsilylether of spiramycin I, 2'-O-acetylspiramycin I 3,18-(O-t-butyldimethylsilyl)acetal was found to be a suitable intermediate for 4''-modification of spiramycin I. Seven 4''-sulfonates and four 4''-alkylethers were synthesized, which were more active against bacteria in vitro than spiramycin I. 4''-Substituted derivatives with relatively small sulfonyl and alkyl groups were comparable in therapeutic effect to spiramycin I.

Animals↗
PubMed1999

Dispensable ribosomal resistance to spiramycin conferred by srmA in the spiramycin producer Streptomyces ambofaciens.

Streptomyces ambofaciens produces the macrolide antibiotic spiramycin, an inhibitor of protein synthesis, and possesses multiple resistance mechanisms to the produced antibiotic. Several resistance determinants have been isolated from S. ambofaciens and studies with one of them, srmA, which hybridized with ermE (the erythromycin-resistance gene from Saccharopolyspora erythraea), are detailed here. The nucleotide sequence of srmA was determined and the mechanism by which its product confers resistance was characterized. The SrmA protein is a methyltransferase which introduces a single methyl group into A-2058 (Escherichia coli numbering scheme) in the large rRNA, thereby conferring an MLS (macrolide-lincosamide-streptogramin type B) type I resistance phenotype. A mutant of S. ambofaciens in which srmA was inactivated was viable and still produced spiramycin, indicating that srmA is dispensable, at least in the presence of the other resistance determinants.

Anti-Bacterial Agents↗
PubMed1985

Chemical modification of spiramycins. VI. Synthesis and antibacterial activities of 3,3''-di-O-acyl-4''-O-sulfonyl and 3,3''-di-O-acyl-4''-O-alkyl derivatives of spiramycin I.

3,3''-Di-O-acyl-4''-O-sulfonyl and 3,3''-di-O-acyl-4''-O-alkyl derivatives of spiramycin I were synthesized and evaluated by four parameters, antibacterial activity, affinity to ribosomes, lypophilicity and therapeutic effects. Among them, 3,3''-di-O-acetyl-4''-O-mesyl and 3,3''-di-O-acetyl-4''-O-methylspiramycin I having relatively small substituents at 4''-position were the most effective in mouse protection tests, and the results were comparable to acetylspiramycin.

Animals↗
PubMed1993

Resistance to spiramycin in Streptomyces ambofaciens, the producer organism, involves at least two different mechanisms.

During its stationary phase, Streptomyces ambofaciens produces the macrolide antibiotic spiramycin, and has to protect itself against this antibiotic. Young mycelia, not yet producing spiramycin, are sensitive to it, but they become fully resistant when production begins. In a sensitive mycelium, resistance could be induced by exposure to sub-inhibitory concentrations of spiramycin, and these induced mycelia, like producing mycelia were resistant not only to spiramycin but also to several other macrolide antibiotics. Ribosomes extracted from these resistant mycelia were shown in vitro to be more resistant to spiramycin than ribosomes extracted from sensitive mycelium, indicating that S. ambofaciens possesses a spiramycin-inducible ribosomal resistance to spiramycin and to macrolide antibiotics. Studies with spiramycin non-producing mutants showed that, in these mutants, resistance to spiramycin also varies during cultivation, in that an old culture was much more resistant than a young one. But with these non-producing mutants, the spectrum of resistance was narrower, and in vitro data showed that resistance was not due to ribosomal modification. These results suggest that S. ambofaciens presents at least two distinct mechanisms for spiramycin resistance; a spiramycin-inducible ribosomal resistance, and a second resistance mechanism which might be temporally regulated and which could involve decreased permeability to, or export of, the antibiotic. The two mechanisms are probably at work simultaneously in the producing mycelium, the spiramycin-inducible resistance being induced by endogenous spiramycin. In non-producing mutants, in the absence of self-induction by spiramycin, only the second mechanism is observed.

Anti-Bacterial Agents↗
PubMed1988

Pharmacokinetics of spiramycin in man.

The pharmacokinetics of spiramycin were studied after single and repeated administration by iv and oral routes. Following iv administration of a 500-mg dose in a one-hour infusion, peak serum concentrations were 1.54-3.10 mg/l. These concentrations are higher than MICs of spiramycin for various infectious agents. Eight hours after the end of infusion, the mean serum concentration was close to 0.25 mg/l. Spiramycin is rapidly and widely distributed throughout the body and achieves high ratios of tissue to serum concentrations in bucco-dental, pulmonary and prostatic tissues and skin. The distribution half-life of spiramycin was 10 min. The steady-state volume of distribution (Vdss) and the tissue distribution volume were 5.6 and 4.5 l/kg. The absolute bioavailability of spiramycin was 36% (S.D. +/- 14). Oral doses of spiramycin between 1 and 2 g resulted in linear increase in the peak serum levels and areas under the serum concentration-time curve. Spiramycin does not appear to undergo important metabolic conversion and is mainly excreted via the biliary route. Indeed, in man, the urinary excretion of active compounds represents only 7.6 to 20% of the administered dose. Spiramycin had a terminal elimination half-life of approximately 5 h. Renal clearance (144 ml/min) was much lower than non-renal clearance (887 ml/min). The total body clearance of spiramycin in young adults was 1.42 l/min (S.D. +/- 0.5) but only 0.53 l/min (S.D. +/- 14) in elderly subjects. During repeated iv administration (500 mg tid), steady state was achieved after four doses. Cmax and Cmin were 3.0 and 0.5 mg/l in young adults and 4.5 and 1.75 mg/l in elderly patients. Spiramycin's kinetics differ in several important respects from erythromycin's, notably the larger volume of distribution of spiramycin which reflects the higher tissue concentration. The reduced spiramycin clearance in elderly subjects requires further investigation.

Administration, Oral↗
PubMed1998

Pharmacodynamics and pharmacokinetics of spiramycin and their clinical significance.

The absolute bioavailability of oral spiramycin is generally within the range of 30 to 40%. After a 1 g oral dose, the maximum serum drug concentration was found to be within the range 0.4 to 1.4 mg/L. The tissue distribution of spiramycin is extensive. The volume of distribution is in excess of 300 L, and concentrations achieved in bone, muscle, respiratory tract and saliva exceed those found in serum. The intracellular penetration of spiramycin is also rapid and extensive, with the concentrations in alveolar macrophages 10 to 20 times greater than simultaneous serum concentrations. Spiramycin is less metabolised than some of the other macrolides. The renal excretion of spiramycin is low, with 4 to 20% of the dose being excreted by this route. High concentrations of spiramycin are achieved in bile, which is an important route of elimination. The serum elimination half-life of spiramycin is between 6.2 and 7.7 hours. Of significance to clinicians may be the finding that spiramycin is highly concentrated in the respiratory tract and other tissues and macrophages. The post-antibiotic effect of spiramycin is significant and this effect is more prolonged than that of erythromycin against Staphylococcus aureus. Spiramycin has also been shown to greatly reduce the capacity of strains of Gram-positive cocci to adhere to human buccal cells.

Animals↗
PubMed1988

Spiramycin uptake by alveolar macrophages.

The in-vitro and in-vivo uptake of spiramycin by human and animal alveolar macrophages was studied. In-vitro penetration was studied in guinea pig and human alveolar macrophages incubated in medium 199 at 37 degrees C containing spiramycin at various concentrations. Results were expressed as the cellular/extracellular concentration ratio (C/E). The in-vivo study was performed in patients receiving 500 or 1000 mg spiramycin every 8 h as a 1-h infusion on day 1. A single infusion was given on day 2, 2 h before serum and bronchoalveolar lavage (BAL) sampling. Spiramycin was assayed by HPLC, and by a microbiological assay. In guinea pig alveolar macrophages, the C/E ratio of spiramycin after 60 min at 37 degrees C was 20.3 +/- 6.5 when the concentration was 10 mg/l. In human alveolar macrophages, the C/E ratio was 21.3 +/- 8.7 at 5 mg/l spiramycin and 23.8 +/- 8.7 at 50 mg/l. The accumulated spiramycin was slowly released when the cells (guinea pig alveolar macrophages) were washed and re-incubated in antibiotic free medium. Spiramycin was able to penetrate the alveolar space. In BAL supernatant, spiramycin levels were about 24-fold the serum level (n = 6 patients), when the BAL/serum glucose ratios were used as the dilution estimate. Alveolar macrophage levels ranged from 17 to 210 mg/l (n = 6 patients receiving 500 mg spiramycin infusion). These results are consistent with the in-vitro data.

Animals↗
PubMed1994

Pharmacokinetics of spiramycin in the rhesus monkey: transplacental passage and distribution in tissue in the fetus.

Transplacental transfer of spiramycin was investigated in a rhesus monkey model to study whether the antibiotic reaches therapeutic levels in the fetus. Spiramycin concentrations were measured by bioassay and high-performance liquid chromatography. Pharmacokinetic parameters were determined for bioactive spiramycin as measured by the bioassay. Pharmacokinetic pilot studies showed that spiramycin distribution follows a two-compartment model in rhesus monkeys. Following a single intravenous dose of 50 or 250 mg, dose-dependent kinetics were observed. At a dose of 50 mg, 10% of the dose was excreted unchanged in the urine. At the higher dose of 250 mg, an oliguric effect was observed. Spiramycin concentrations in fetal serum were measured over time while the maternal concentration was maintained at a constant level. During a 5-h experiment, a maximum fetal-maternal serum ratio of 0.27 was found. In three fetuses, concentrations in serum and tissue were measured following intravenous administration of 50 mg of spiramycin twice daily to the mother for at least 7 days. The fetal-maternal serum ratios were found to be 0.4 to 0.58 after intravenous administration of the final dose of 50 mg to the mother. It appeared that spiramycin accumulated in the soft tissues, especially in the liver and spleen, of both the mother and the fetus. The concentration in placental tissue appeared to be 10 to 20 times that of the concentration in fetal serum. The concentration of spiramycin in amniotic fluid was about five times higher than the concentration in fetal serum. Another important observation was that absolutely no spiramycin was found in the brain.

Animals↗
PubMed1991

Respiratory tract distribution and bioavailability of spiramycin in calves.

Pharmacokinetic determinants of spiramycin and its distribution into the respiratory tract were studied in 2 groups of calves, 4 to 10 weeks old. Group-A calves (n = 4) were used to determine pharmacokinetic variables of spiramycin after IV (15 and 30 mg/kg of body weight) and oral administrations of the drug (30 mg/kg) and to measure distribution of spiramycin into nasal and bronchial secretions. Group-B calves (n = 4) were used to determine distribution of spiramycin into lung tissue and bronchial mucosa. Spiramycin disposition was best described by use of an open 3-compartment model. Mean (+/- SD) elimination half-life was 28.7 +/- 12.3 hours, and steady-state volume of distribution was 23.5 +/- 6.0 L/kg. Bio-availability after oral administration was 4 +/- 3%. High and persistent concentrations of spiramycin were achieved in the respiratory tract tissues and fluids. Tissue-to-plasma concentration ratio was 58 for lung tissue and 18 for bronchial mucosa at 3 hours after spiramycin administration and 137 and 49, respectively at 24 hours. Secretion-to-plasma concentration ratio was 4 for nasal secretions and 7 for bronchial secretions, and remained almost constant with time. Thus, spiramycin penetrates well into the respiratory tract, although the value in bronchial secretions is lower than that in lung tissues and bronchial mucosa. Calculations indicate that a loading dose of 45 mg/kg, administered IV, followed by a maintenance dose of 20 mg/kg, IV, once daily is required to maintain active concentrations of spiramycin against bovine pathogens in bronchial secretions.

Animals↗
PubMed1998

[Toxoplasmosis retinochorioiditis, a therapy comparison between spiramycin and pyrimethamine/sulfadiazine].

BACKGROUND: The treatment of toxoplasma retinochoroiditis with spiramycin is an alternative to sulfadiazine and pyrimethamine. The treatment with sulfadiazine is associated with multiple side effects. Sulfadiazine is contraindicated during pregnancy and breastfeeding period. Spiramycin has less side effects and is recommended during pregnancy and breastfeeding period. The efficacy of spiramycin in treatment of toxoplasma retinochoroiditis is still a matter of controversy. PATIENTS AND METHODS: In a retrospective study, side effects and outcome of therapy in 44 patients with toxoplasma retinochoroiditis treated with sulfadiazine and pyrimethamine (n = 30) or spiramycin (n = 14) were compared. We assessed duration of therapy and healing, ophthalmoscopic findings and observed side effects. RESULTS: The mean healing time in the group of spiramycin was 63.83 days in comparison to 88 days for the group of patients treated with sulfadiazine/pyrimethamine. The frequency of side effects was lower in the group treated with spiramycin. CONCLUSION: In comparison to a combined application of sulfadiazine and pyrimethamine the treatment with spiramycin alone requires a shorter duration of therapy and healing period. Additionally, side effects and contraindications appear to be less frequent. In view of these findings, spiramycin therapy must be considered as a promising approach in the treatment of toxoplasma retinochoroiditis.

Adult↗
PubMed1991

Coloning and expression of spiramycin polyketide synthase genes and resistance genes from S. spiramyceticus U-1941.

The plasmid containing the spiramycin polyketide synthase genes, pCN3H8, was obtained from the genomic library of spiramycin producing strain, S. spiramyceticus U-1941, using homologous DNA to actI and actIII genes as hybridization probes. Restriction analysis of the plasmid pCN3H8 showed that the molecular weight was 44kb. The regions homologous to the actI & actIII genes were localized by Southern hybridization, and corresponding DNA fragments were subcloned onto E. coli-Streptomyces shuttle vector pWHM3. A recombinant plasmid pCG4 was obtained. Transformation of the pCN3H8 DNA into the polyketide synthase deficient mutant of midecamycin producing strain, S. mycarofaciens subsp. No. 68, resulted in the production of midecamycin A by UV analysis. Transformation of the pCN3H8 DNA into the polyketide synthase deficient mutant of actinorhodin producing strain, S. coelicolor TK17, resulted in the production of an antibacterial compound which was neither similar to actinorhodin in color nor to spiramycin by paper chromatographic analysis. Transformant of S. lividans with pCN3H8 DNA produced an antibacterial compound as well. Resistance to spiramycin was expressed in transformants of spiramycin sensitive strain, S. griseofuscus, with pCN3H8 DNA. A plasmid pSG3 DNA with molecular weight of 7.0kb, isolated from the transformant, might be a result of in vivo deletion of pCN3H8 in S. griseofuscus. Retransformation of pSG3 DNA into S. griseofuscus confirmed that the gene of resistance to spiramycin was on the plasmid pSG3 DNA. Transformation of spiramycin producing strain, S. ambofaciens, with pCG4 or pSG3 DNA increased spiramycin production in fermentation broth.

Cloning, Molecular↗
PubMed1988

Early studies on in-vitro and experimental activity of spiramycin: a review.

This review of spiramycin activity in vitro is based mainly on early studies. The MICs of spiramycin for common pathogenic bacteria such as staphylococci, streptococci and pneumococci are higher than those of erythromycin. Conversely, in experimental models, the activity of spiramycin is equal to or greater than that of erythromycin. In addition, the activity of spiramycin on Neisseria, Legionella, Mycoplasma, Chlamydia, and Toxoplasma spp. completes its antimicrobial spectrum and shows that spiramycin covers the majority of agents responsible for respiratory tract infections. The 'spiramycin paradox'-the discrepancy between the relatively modest activity of spiramycin in vitro and its excellent activity in vivo will be explained by other papers. Its high tissue and intracellular concentrations, and the slow recovery of bacteria submitted to spiramycin are of great importance to account for its activity in vivo.

Bacteria↗