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Interactions of macrolide antibiotics (Erythromycin A, roxithromycin, erythromycylamine [Dirithromycin], and azithromycin) with phospholipids: computer-aided conformational analysis and studies on acellular and cell culture models.

The potential of 14/15 membered macrolides to cause phospholipidosis has been prospectively assessed, and structure-effects examined, using combined experimental and conformational approaches. Biochemical studies demonstrated drug binding to phosphatidylinositol-containing liposomes and inhibition of the activity of lysosomal phospholipase A1 toward phosphatidylcholine included in the bilayer, in close correlation with the number of cationic groups carried by the drugs (erythromycin A </= roxithromycin < erythromycylamine </= azithromycin). In cultured cells (fibroblasts), phospholipidosis (affecting all major phospholipids except sphingomyelin) was observed after 3 days with the following ranking: erythromycin A </= roxithromycin < erythromycylamine < azithromycin (roxithromycin could, however, not be studied in detail due to intrinsic toxicity). The difference between erythromycylamine and azithromycin was accounted for by the lower cellular accumulation of erythromycylamine. In parallel, based on a methodology developed and validated to study drug-membrane interactions, the conformational analyses revealed that erythromycin A, roxithromycin, erythromycylamine, and azithromycin penetrate into the hydrophobic domain of a phosphatidylinositol monolayer through their desosamine and cladinose moieties, whereas their macrocycle is found close to the interface. This position allows the aminogroups carried by the macrocycle of the diaminated macrolides (erythromycylamine and azithromycin) to come into close contact with the negatively charged phosphogroup of phosphatidylinositol, whereas the amine located on the C-3 of the desosamine, common to all four drugs, is located at a greater distance from this phosphogroup. Our study suggests that all macrolides have the potential to cause phospholipidosis but that this effect is modulated by toxicodynamic and toxicokinetic parameters related to the drug structure and mainly to their cationic character.

Anti-Bacterial Agents↗

Increased kasugamycin sensitivity in Escherichia coli caused by the presence of an inducible erythromycin resistance (erm) gene of Streptococcus pyogenes.

An inducible erythromycin resistance gene (erm) of Streptococcus pyogenes was introduced into Escherichia coli by transformation with a plasmid. The recipient E. coli cells were either kasugamycin sensitive (wildtype) or kasugamycin resistant (ksgA). The MIC values of erythromycin increased from 150 micrograms/ml to greater than 3000 micrograms/ml for E. coli. An extract of transformed cells, particularly a high-salt ribosomal wash, contained an enzyme that was able to methylate 23S rRNA from untransformed cells in vitro; however, 23S rRNA from transformed cells was not a substrate for methylation by such an extract. 165 rRNA and 30S ribosomal subunits of either the wild type or a kasugamycin resistant (ksgA) mutant were not methylated in vitro. Transformation of E. coli by the erm-containing plasmid led to a reduction of the MIC values for kasugamycin. This happened in wild-type as well as in ksgA cells. However, in vitro experiments with purified ksgA encoded methylase demonstrated that also in erm transformed E. coli, the ksgA encoded enzyme was active in wild-type, but not in ksgA cells. It was also shown by in vitro experiments that ribosomes from erm ksgA cells have become sensitive to kasugamycin. Our experiments show that in vivo methylation of 23S rRNA, presumably of the adenosine at position 2058, leads to enhanced resistance to erythromycin and to reduced resistance to kasugamycin. This, together with previous data, argues for a close proximity of the two sites on the ribosome that are substrates for adenosine dimethylation.

Aminoglycosides↗

Erythromycin ototoxicity in liver transplant patients.

We report on three liver transplant patients who developed erythromycin-related ototoxicity. This complication has been described in renal transplant patients and in patients with liver dysfunction, but to our knowledge it has not yet been reported in liver transplant patients. The influence of hepatic dysfunction, common renal failure, and the interaction between cyclosporin and erythromycin in the development of erythromycin ototoxicity are discussed.

Adult↗

[The effect of chloramphenicol on sleep in cat -- comparison with thiamphenicol, erythromycine, and oxytetracycline (author's transl)].

The effects of various antibiotics, which inhibit protein synthesis, has been studied on the sleep-waking cycle of cats. Chloramphenicol (CAP) selectively inhibits paradoxical sleep (SP). Thiamphenicol (TAP) and oxytetracycline however are ineffective; erythromycine induces only a small decrease of SP. When CAP is injected after TAP, the SP inhibition is longer than after CAP alone. Combining erythromycine and CAP produces the same effect as one or other of the antibiotic alone, depending only on the interval between administration of the two drugs. Slow wave sleep is decreased only with high doses of CAP and is unaffected by TAP, oxytetracycline or erythromycine. These results suggest that CAP may inhibit a peptide or protein synthesis involved in the mechanisms of SP.

Animals↗

Ultrastructural analysis of the effects of erythromycin on the morphology and developmental cycle of Chlamydia trachomatis HAR-13.

The effect of erythromycin (10 micrograms/ml) on the morphology and developmental cycle of Chlamydia trachomatis HAR-13 was examined by electron microscopy. When the antibiotic was added later than 24 h post infection, the HAR-13 morphology or developmental cycle was not altered. Addition at 18 or 24 h post infection inhibited glycogen production, blocked the transformation of the reticulate body to elementary body, and produced ghost bodies and reticulate bodies twice the diameter of untreated reticulate bodies. When erythromycin was added within 12 h post infection, the conversion of the elementary body to reticulate body was inhibited. Erythromycin (10 micrograms/ml) was bactericidal to strain HAR-13 throughout the developmental cycle.

Chlamydia trachomatis↗

Chromosomal and extrachromosomal inheritance of erythromycin-resistance in the "petite-negative" yeast Kluyveromyces lactis.

Spontaneously arising erythromycin-resistant mutants were isolated in the "petite-negative" yeast Kluyveromyces lactis. Two independently arising mutants were studied, in one erythromycin-resistance was conferred by a single dominant nuclear gene, and in the other the resistance was extrachromosomally inherited. In fermentable medium growth of sensitive and resistant strains in presence or absence of erythromycin does not qualitatively change the cytochrome absorption spectra, whereas oxygen uptake of parental strains growing in glucose-medium is affected by the drug. The importance of "petite-negative" yeasts like Kluyveromyces lactis for the study of nucleo-cytoplasmic interrelations is discussed.

Chromosomes↗

Erythromycin resistant mutations in Bacillus subtilis cause temperature sensitive sporulation.

All of several hundred erythromycin resistant single site mutants of Bacillus subtilis W168 are temperature senstive for sporulation. The mutants and wild type cells grow vegetatively at essentially the same rates at both permissive (30 degrees C) and nonpermissive (47 degrees C) temperatures. In addition cellular protein synthesis, cell mass increases and cell viabilities are similar in mutant and wild type strains for several hours after the end of vegetative growth (47 degrees C). in the mutants examined, the temperature sensitive periods begin when the sporulation process is approximately 40% completed, and end when the process is 90% completed. At nonpermissive temperatures, the mutants produce serine and metal proteases at 50% of the wild type rate, accumulate serine esterase at 16% of the wild type rate, and do not demonstrate a sporulation related increase in alkaline phosphatase activity. The eryR and spots phenotypes cotransform 100%, and cotransduce 100% using phage PBS1. Revertants selected for ability to sporulate normally at 47 degrees C (spot), simultaneously regain parental sensitivity to erthromycin. No second site revertants are found. Ribosomes from eryR spots strains bind erythromycin at less than 1% of the wild type rate. A single 50S protein (L17) from mutant ribosomes shows an altered electrophoretic mobility. Ribosomes from spo+ revertants bind erythromycin like parental ribosomes and their proteins are electrophoretically identical to wild type. These data indicate that the L17 protein of the 50S ribosomal subunit from Bacillus subtilis may participate specifically in the sporulation process.

Bacillus subtilis↗

[Erythromycin versus amoxicillin for the treatment of pneumonia in children (author's transl)].

Following a study in which the etiology of nearly 70% of 142 cases of pneumonia in children could be determined using a combination of bacteriological and serological methods, the effect of erythromycin ethylsuccinate was compared with that of amoxicillin in a randomized study on 120 cases of pneumonia. We first examined the tracheal secretion microbiologically and determined other serological parameters and clinical data. The tracheal secretion was sterile in only 19% of the cases. We were able to identify the etiology in 64% of the cases using a combination of microbiological and serological methods. A discontinuation of therapy and acceptable side-effects were considerably more frequent with amoxicillin than with erythromycin ethylsuccinate (75 mg/kg body weight). The advantages of erythromycin, especially for the initial therapy of pneumonia, and the improvements in diagnosis resulting from the examination of the tracheal secretion will be discussed.

Amoxicillin↗

Emergence of resistance to erythromycin and fluoroquinolones in thermotolerant Campylobacter strains isolated from feces 1987-1991.

During the period 1987 to 1991 a retrospective study was performed to determine the resistance of thermotolerant Campylobacter species isolated from feces to erythromycin and fluoroquinolones. Of the 672 strains studied, 614 (91.3%) were identified as Campylobacter jejuni and 58 (8.7%) as Campylobacter coli. During the study period the rate of resistance of Campylobacter jejuni to erythromycin remained relatively stable (0.9-3.5%), while resistance of Campylobacter coli to erythromycin emerged later (1989) with much higher rates (14.8-33%). Overall, 11.8% and 10.7% of Campylobacter jejuni strains isolated after 1987 were resistant to nalidixic acid and ciprofloxacin respectively, resistance increasing from 2.3% in 1988 to 32% in 1991. In 1991 the first strains of Campylobacter coli with resistance to these fluoroquinolones were detected (rates 29% and 26% respectively). Of the strains resistant to nalidixic acid, only 10.9% were susceptible to ciprofloxacin.

Anti-Infective Agents↗

Bioassay for A-56268 (TE-031) and identification of its major metabolite, 14-hydroxy-6-O-methyl erythromycin.

A-56268 is a new macrolide which is generally two-fold more potent than erythromycin. A new bioassay is described in which plasma samples are extracted with acetonitrile prior to bioassay. The concentration range for the assay is between 0.05-4.0 micrograms/ml, and the concentrations measured are within 6% of those measured by high-power liquid chromatography. An active metabolite which is as active as erythromycin was identified in the plasma. The plasma half-life and area under the plasma curve values of A-56268, as determined by bioassay, were significantly greater than those of erythromycin.

Biological Assay↗

Comparative in vitro activity of the new erythromycin derivative dirithromycin against gram-positive bacteria isolated from cancer patients.

The in vitro activity of dirithromycin (LY-237216), a new macrolide erythromycin derivative, was compared to that of four other agents (clarithromycin, erythromycin, roxithromycin, clindamycin) against 334 gram-positive isolates obtained from cancer patients. Dirithromycin was similar in potency and antimicrobial spectrum to the other agents tested. It was very active against beta-haemolytic streptococci and Streptococcus pneumoniae, and moderately active against penicillin and methicillin susceptible Staphylococcus aureus, Bacillus spp., Listeria monocytogenes and Corynebacterium jeikeium. Erythromycin resistant organisms were also resistant to dirithromycin.

Anti-Bacterial Agents↗

L-arginine/nitric oxide pathway modulates gastric motility and gallbladder emptying induced by erythromycin and liquid meal in humans.

There is recent evidence that nitric oxide, a soluble gas produced from L-arginine, is released by the smooth muscle cells and neurons of the gastrointestinal tract where it exerts a myorelaxive action. However, little is known about the effects nitric oxide has on gastric and gallbladder motility during the inter- and postprandial phases in man. We therefore investigated the effects 200 mg/kg/hr L-arginine exerts on the gastric and gallbladder motility induced by 2 mg/kg erythromycin or a liquid meal in 21 subjects in a double-blind, placebo-controlled study. Gastric and gallbladder emptying were evaluated by sonography. Fasting antral motility was expressed as antral motility index (MI). In fasting subjects, L-arginine administration determined a threefold increase in plasma nitrite concentrations. Administration of erythromycin caused a significant rise in the antral MI, which was inhibited by L-arginine (P < 0.05). Ingestion of a liquid meal also significantly increased antral MI, but it returned to basal values 90 min after the end of the meal. Although L-arginine administration caused a significant reduction in the antral MI (P < 0.05), it did not inhibit gastric emptying. L-Arginine provoked an approximately 40% increase in basal gallbladder volume, completely blocked erythromycin-induced emptying, and partially, but significantly, prevented the emptying induced by a liquid meal (P < 0.01). Our study suggests that nitric oxide may be implicated in the physiological modulation of gastric and gallbladder motility during the inter- and postprandial phases in man.

Adult↗

Determination of the optimal feeding regime during biosynthesis of erythromycin.

A systems approach to the analysis of the process of fermentaton of erythromycin in demonstrated. On the basis of biochemical and bioengineering data obtained in hydrodynamic tests and pilot plant fermentations of erythromycin a mathematical model for optimal technological parameters of growth of Streptomyces erythreus and product formation was postulated. The optimal regime was simulated and subsequently verified. The production of erythromycin increased to 112%.

Culture Media↗

Modelling the adsorption kinetics of erythromycin onto neutral and anionic resins.

In this study the selective adsorption method was chosen to enable the recovery of erythromycin. The following sorbents were tested: neutral resins (XAD-4, XAD-7 and XAD-16) and an anionic resin (IRA-410). A mathematical kinetic model for the adsorption of erythromycin against time, on XAD-4, XAD-7 and XAD-16 resins, is proposed. Both Freundlich and Langmuir models showed a good fit for the sorbents XAD-7 and IRA-410 resins. The highest adsorption efficiency was observed when synthetic neutral resin, XAD-7 and XAD-16, were used. The estimated affinity and concentration factors show that the neutral resins tested are adequate for the selective adsorption of erythromycin. The estimated values of enthalpy and free energy of adsorption, lower than 12 kJ mol(-1) and -2 kJ mol(-1), respectively, indicate that a physiosorption process occurred.

Acrylic Resins↗

Clonal relationships among isolates of erythromycin-resistant Streptococcus pyogenes of different geographical origin.

The clonal relationships among 261 erythromycin-resistant Streptococcus pyogenes isolates collected in 1986-1997 from nine countries in Europe and North and South America were studied by using two molecular typing methods: Vir typing and random amplified polymorphic DNA (RAPD) analysis. A total of 49 different Vir genotypes (VTs) and 33 different RAPD patterns were noted among the 261 isolates. Isolates that shared the same VT and RAPD pattern were considered to belong to the same clone. Although as many as 60 different clones were found among the isolates studied, only seven clones, comprising 157 of the 261 (60%) isolates, were found in more than one country. Five of these seven clones expressed the M phenotype known to be associated with the drug efflux mechanism, and only two clones expressed the macrolide-lincosamide-streptogramin B-resistance phenotype. The results indicate a polyclonal spread of erythromycin-resistant Streptococcus pyogenes. Furthermore, predominance of the seven clones indicates that erythromycin-resistant Streptococcus pyogenes of the same clonal origin may be widely distributed and found in several different countries.

Drug Resistance, Bacterial↗

Relative potency of telithromycin, azithromycin and erythromycin against recent clinical isolates of gram-positive cocci.

A ketolide (telithromycin), an azalide (azithromycin) and a macrolide (erythromycin) were tested against 2,733 isolates of gram-positive cocci gathered from 11 different medical centers. Telithromycin was active against erythromycin-resistant staphylococci that were susceptible to clindamycin but was not active against those that were resistant to clindamycin. More than 99% of all Streptococcus pneumoniae and Streptococcus pyogenes isolates were susceptible to 1 microg/ml of telithromycin including erythromycin- and azithromycin-resistant strains. Telithromycin was not only more potent than azithromycin against macrolide-susceptible strains, it was also active against most macrolide-resistant strains. Although the prevalence of macrolide-resistant pneumococci increased from 19% to 27% between 1997 and 1999, macrolide resistance among other gram-positive cocci did not change substantially in that 2-year period.

Anti-Bacterial Agents↗

Increased erythromycin production by alginate as a medium ingredient or immobilization support in cultures of Saccharopolyspora erythraea.

Erythromycin production by Saccharopolyspora erythraea immobilized in 2% (w/v) calcium alginate or grown in medium containing 20 g sodium alginate/l inoculated with free cells was almost twice more than that of the control. S. erythraea did not consume alginate, agar, dextran, silicon antifoaming agent or cyclodextrin as a carbon source, although, all of these increased the production of erythromycin. Highest titer of erythromycin (2.3 times more than that of the control) was achieved in medium containing 1 g agar/l.

Agar↗

Improvement of Bacillus thuringiensis delta-endotoxins synthesis yields through acquisition of erythromycin resistance.

The acquisition of the erythromycin resistance by Bacillus thuringiensis kurstaki improved yields of delta-endotoxins in sporulating cells ranging from 134 to 215%. Resistance to erythromycin decreased the final spore count by at least 50%. Consequently, erythromycin resistance is an efficient tool for the improvement of bioinsecticides yields with a high ratio of delta-endotoxins to spores.

Bacillus thuringiensis↗