We reconstructed the erythromycin macrocyclic lactone (6-deoxyerythronolide B, 6dEB) synthesis pathway in Escherichia coli. We first cloned all the genes needed to synthesize the 6dEB into multi-gene co-expressed vectors. Then using the recognition sequences of isoschizomers Xba I/Spe I of vectors, we assembled the related genes into a series multiple-genes recombinant plasmids pBJ144, pBJ130. The recombinant plasmids pBJ144, pBJ130 were cotransformed into BAP1 to get the recombinant BAP1(pBJ144/pBJ130). SDS-PAGE analysis showed that individual genes were expressed correctly. After inducing at low temperature, adding propionate as substrate, we validated the crude product by mass spectrometry and the 6dEB yield was about 10 mg/L. These results indicated that the synthetic pathway of 6dEB was successfully assembled and reconstructed in Escherichia coli, which will greatly facilitate the reconstruction of whole erythromycin synthesis pathway and finally help to establish a stable research platform for developing of new derivatives of erythromycin and combinatorial biosynthesis of polyketide-type antibiotics.
Anti-Bacterial Agents ; biosynthesis ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Erythromycin ; analogs & derivatives ; biosynthesis ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics

Drug-resistance has become a challenging clinical problem. Ketolides, a new class of erythromycin derivatives, have shown promising effectiveness in killing drug-resistant bacteria. This article reviews recent development in synthesis of ketolides, with focus on the modification and synthesis of some important positions on erythromycin A cycles.
Animals ; Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Drug Resistance, Bacterial ; Erythromycin ; analogs & derivatives ; chemical synthesis ; pharmacology ; Humans ; Ketolides ; chemical synthesis ; chemistry ; pharmacology ; Macrolides ; chemical synthesis

OBJECTIVETo investigate the effect of interstitial cells of Cajal (ICC) on contraction of intestinal tract smooth muscle induced by motilin receptor agonist.

METHODSTwo kinds of smooth muscle segments were isolated from the duodenum and colon of rabbit. Both kinds of smooth muscle were divided into two groups: group a (normal ICC group of duodenum); group c (impaired ICC group of duodenum); group b (normal ICC group of colon); group d (impaired ICC group of colon), each group contained 20 segments. The impairment of ICC was induced by selectively destroying ICC in the smooth muscle via treatment with methylene blue plus light. Then the frequency and amplitude of contraction of group a and c, group b and d was compared. Then motilin receptor agonist (ABT-229) was added into the Krebs solution, the frequency and amplitude of smooth muscle contraction before and after adding ABT-229 were recorded and compared.

RESULTSThe electron microscopy demonstrated that ICC in methylene blue plus light group were destroyed; the smooth muscle cells and neuron scattered close to ICC were normal. In group a, the contraction frequency, (17.89 +/- 1.88) times/min, was significantly lower as compared with that measured after ABT-229 was added [(18.76 +/- 1.18) times/min (P > 0.05)]; the amplitude of group a was (343 +/- 28) mg, which was lower as compared with that after adding ABT-229 [(597 +/- 68) mg (P < 0.001)]; in group b, the frequency was (5.89 +/- 1.03) times/min, the amplitude was (724 +/- 85) mg, after ABT-229 was added, the construction frequency increased to (8.45 +/- 0.69) times/min (P < 0.001), and the amplitude was (897 +/- 89) mg (P < 0.05), which was not affected by pretreatment with TTX, however it could be weakened by nifedipine significantly. In group c and d, the rhythmic contraction almost disappeared: in group c the contraction frequency was (1.06 +/- 0.24) times/min, and the amplitude were (50 +/- 10) mg. In group d, the amplitude and frequency significantly decreased as compared with the normal group (P < 0.001), in group c, and d, no significant difference in amplitude and frequency was found between the values measured before and after adding ABT-229 (P > 0.05). After Ach (100 micromol/L) was added, both group c and d could generate contraction.

CONCLUSIONICC may play an important role in the rhythmic contraction of intestinal tract. The promoting effect of motilin receptor agonist on intestinal tract may be mediated by ICC. ICC deficiency may cause functional impairment of gastrointestinal tract motivation. The medication may become ineffective when the number of ICC is reduced to a certain extent or the network of ICC is incomplete.

Animals ; Erythromycin ; analogs & derivatives ; pharmacology ; Female ; Gastrointestinal Motility ; drug effects ; physiology ; Interstitial Cells of Cajal ; physiology ; Male ; Rabbits ; Receptors, Gastrointestinal Hormone ; agonists ; Receptors, Neuropeptide ; agonists

Genetic engineering on macrolide antibiotics was a new field in recent years and more than 100 novel polyketides had been produced until then. Using genomic DNA of S. erythraea A226 as a template, about 3.2 kb DNA fragment without KR6 domain was amplified by overlapping PCR technique and cloned into pWHM3 carrier, which resulted in the construction of homologous recombinant plasmid pWHM2201. Plasmid pWHM2201 was introduced into protoplasts of S. erythraea A226 by PEG-mediated transformation and integrated into the gene locus for erythromycin biosynthesis. After integrants grew for two generations on R3M media without Tsr, they were protoplasted and grown on R3M plates. By PCR identification, 8 mutants without KR6 domain were selected out and named S. erythraea M(1-8). With the identification of mass spectrometry, it was proved that S. erythraea M1 synthesized a novel ketolide compound 3-deoxy-3-oxo-erythronolide B.
Anti-Bacterial Agents ; biosynthesis ; chemistry ; Chromosomes, Bacterial ; Erythromycin ; analogs & derivatives ; biosynthesis ; chemistry ; Genetic Engineering ; Ketolides ; Molecular Structure ; Multienzyme Complexes ; genetics ; Saccharopolyspora ; enzymology ; genetics ; metabolism

AIMTo synthesizs of derivatives of (9S)-12-methylene erythromycin possessed potent antibacterial activity.

METHODSUsing erythromycin A as a starting material, via two intermediate compounds protected 12,21-dehydroerythromycin A and 6,7: 12,21-didehydro erythromycin A, several 9-O, 11-O-ethylidene compounds were obtained. During this process, benzyl and isopropyl have been selected as the protecting group. The structures of compounds obtained were confirmed with 13C NMR and MS-FAB. Their antibacterial activity in vitro was tested.

RESULTSEleven derivatives of erythromycin were synthesized. Five of them were unknown compounds.

CONCLUSIONThe preliminary biological test showed that two target compounds exhibited less potent antibacterial activity in vitro.

Anti-Bacterial Agents ; chemical synthesis ; pharmacology ; Erythromycin ; analogs & derivatives ; chemical synthesis ; pharmacology ; Microbial Sensitivity Tests ; Staphylococcus aureus ; drug effects ; Staphylococcus epidermidis ; Streptococcus pneumoniae ; drug effects

OBJECTIVE: To determine the pharmacokinetics of erythromycin stinoprate capsules and to provide guidance for clinical research. METHODS: Thirty healthy volunteers (15 men and 15 women) were divided into 3 groups randomly, each including 5 men and 5 women. Single oral doses of 250, 500 and 750 mg were given to each volunteer. The concentrations of erythromycin propionate and erythromycin base in the plasma were determined by HPLC-MS. RESULTS All 30 volunteers completed the experiment without adverse reactions. Using 3P87 we analyzed the model and calculated the pharmacokinetic parameters. Three dose groups taking high, middle and low dose were all single compartment model. The pharmacokinetic parameters of erythromycin propionate after taking erythromycin stinoprate capsules were as follows: Low dose group: Ka (2.007 +/- 1.281 )/h, tmax ( actual value) (1.9 +/- 0.6) h, Cmax (437.0 +/- 295.0) microg/L, AUC0-14 (trapezoid area) (1840.2 +/- 1476.87) microg x h/L, Ke (0.329 +/- 0.119)/h, T1/2 (2.45 +/- 0.9) h. Middle dose group: Ka (1.451 +/- 0.380)/h, tmax (1.7 +/- 0.3) h, Cmax (923.1 +/- 217.5) microg/L, AUC0-14 (4542.44 +/- 1579.4) microg x h/L,Ke (0.237 +/- 0.057)/h, T1/2 (3.1 +/- 1.1) h; High dose group: Ka (2.076 +/- 1.559)/h, tmax (1.7 +/- 0.3) h, Cmax (1336.5 +/- 366.0) microg/L, AUC0-14 (7481.5 +/- 2496.2) microg x h/L, Ke (0.266 +/- 0.051)/h, T1/2 (2.7 +/- 0.5) h. The pharmacokinetic parameters of erythromycin were as follows: Low dose group: Ka (1.410 +/- 0.626)/h, tmax (1.8 +/- 0.5) h, Cmax (197.5 +/- 227.6) microLg/L, AUC0-14 (766.4 +/- 981.0) microg x h/L, Ke (0.519 +/- 0.240)/ h, T1/2 (1.6 +/- 0.8) h. Middle dose group: Ka (1.900 +/- 1.049)/h, tmax (1.6 +/- 0.2) h,Cmax (488.3 +/- 216.7) microg/L, AUC0-14( 488.3 +/- 216.7) microg/L, Ke (0.329 +/- 0.057)/h, T1/2(2.2 +/- 0.4) h; High dose group: Ka (1.934 +/- 0.794)/h, tmax (1.7 +/- 0.3) h, Cmax (749.3 +/- 387.2) microg/L, AUC0-14(3820.1 +/- 1966.4) microg x h/L, Ke (0.373 +/- 0.174)/h, T1/2( 2.2 +/- 0.7) h. AUC of both erythromycin propionate and erythromycin base was linearly correlated to the doses; T1/2 was not correlated to the doses, so they followed the first order processes. The pharmacokinetic parameters of erythromycin The erythromycin stinoprate propionate and erythromycin base had no gender differences. Conclusion was absorbed as erythromycin propionate. Cmax reached at about 1.6 h. T1/2 of elimination was 2.4-3.1 h. The active component of erythromycin propionate was erythromycin. Cmax of erythromycin is 1.8, T1/2 is 2.4-3.1 h. In the range of oral dose of 250 to 750 mg, both erythromycin propionate and erythromycin base accorded the first order processes. The pharmacokinetic parameters were different with those reported in foreign documents while the gender difference did not exist in Chinese adults.
Adult ; Area Under Curve ; Biological Availability ; Capsules ; Chromatography, High Pressure Liquid ; methods ; Erythromycin ; administration & dosage ; analogs & derivatives ; pharmacokinetics ; Female ; Humans ; Male

The efficacy and safety of clarithromycin, roxithromycin and erythromycin stearate in mild pneumonia were compared in an open randomized trial. Eighty-six male patients, doing their obligatory military service, ranging between 19 and 24 years of age (mean 20), were randomly treated: 29 with clarithromycin 500 mg 12-hourly, 30 with roxithromycin 150 mg 12-hourly, and 27 with erythromycin stearate 500 mg 6-hourly, each course being administered for 10 days. Seventy-eight patients were able to be evaluated for efficacy, 28 receiving clarithromycin, 28 roxithromycin, and 22 erythromycin stearate. There were no significant differences among the groups in terms of clinical success rates (clinical cure or improvement: 89% for clarithromycin, 82% for roxithromycin, and 73% for erythromycin stearate, p = 0.32). However, we found that there were significant differences among the groups in terms of clinical cure rates (75% for clarithromycin, 64% for roxithromycin, and 41% for erythromycin stearate, p = 0.04). Adverse events, mostly gastrointestinal, caused discontinuation of treatment in 3.4% of the patients in the clarithromycin group, in 6.6% of the patients in the roxithromycin group, and in 18.5% of the patients in the erythromycin stearate group. The results indicate that there were no statistically significant differences among the three treatment groups in terms of clinical success rates, but that clarithromycin and roxithromycin were better tolerated.
Adult ; Antibiotics, Macrolide/therapeutic use* ; Antibiotics, Macrolide/adverse effects ; Clarithromycin/therapeutic use* ; Clarithromycin/adverse effects ; Comparative Study ; Erythromycin/therapeutic use* ; Erythromycin/analogs & derivatives* ; Erythromycin/adverse effects ; Female ; Human ; Male ; Pneumonia/radiography ; Pneumonia/physiopathology* ; Pneumonia/microbiology ; Pneumonia/drug therapy* ; Radiography, Thoracic ; Roxithromycin/therapeutic use* ; Roxithromycin/adverse effects

The derivatives of (9S)-9-hydroxyl-12-methylene erythromycin A were synthesized by using erythromycin A as a starting material. An intermediate (9S)-9,11-O-isopropylidene-6-O-allyl-2' ,4"-O-bis(benzoyl)-12,21-anhydro erythromycin A 12 was obtained. The antibacterial activity in vitro of two compounds, 6 and 11, was tested. The preliminary biological test showed that two compounds exhibited less potent antibacterial activity in vitro.
Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Erythromycin ; analogs & derivatives ; chemical synthesis ; chemistry ; pharmacology ; Microbial Sensitivity Tests ; Molecular Structure ; Staphylococcus aureus ; drug effects ; Staphylococcus epidermidis ; drug effects ; Streptococcus pneumoniae ; drug effects

Anti-Bacterial Agents ; pharmacology ; Child ; Dyspepsia ; drug therapy ; Erythromycin ; analogs & derivatives ; pharmacology ; therapeutic use ; Gastroesophageal Reflux ; drug therapy ; Gastrointestinal Motility ; drug effects ; Humans ; Motilin ; pharmacology ; Receptors, Gastrointestinal Hormone ; drug effects ; Receptors, Neuropeptide ; drug effects

OBJECTIVETo analyze the mechanisms of macrolide resistance in Streptococcus pneumoniae from children in Beijing.

METHODSThe MICs of penicillin and erythromycin were determined by the E-test methods for 200 Streptococcus pneumoniae isolates collected from 2002 to 2003 at Beijing Children's Hospital. MICs of azithrhomycin, clarithromycin, acetylspiramycin and clindamycin for 147 erythromycin-resistant isolates were detected by the agar dilution methods. For phenotyping, macrolide resistance induction tests were used in erythromycin-resistant isolates. PCR was used to determine the presence of the erythromycin-resistant genes.

RESULTSOf 200 Streptococcus pneumoniae isolates, 89.5% were resistant to erythromycin. In 147 erythromycin-resistant isolates, resistance rates were as follows: azithromycin, 100%; clarithromycin, 100%; acetylspiramycin, 95.2%; and clindamycin, 95.9%. The most common macrolide resistance phenotype was the cMIS phenotype (95.9%), 1.4% had the iMLS phenotype and 2.7% the M phenotype. Erythromycin-resistant isolates were characterized for the underlying resistance genotype, with 79.6% having the ermB genotypes, 17.7% having both ermB and mefA, 2.7% having the mefA, and none having neither ermB nor mefA genotypes.

CONCLUSIONSThe rates of carriage of macrolide-resistant Streptococcus pneumoniae by children were high in Beijing during 2002 - 2003. cMLS was the most prevalent phenotype among erythromycin-resistant Streptococcus pneumoniae isolates, and ribosomal modification (ermB gene coded) was the main resistance mechanism against macrolides in Beijing region.

Anti-Bacterial Agents ; pharmacology ; Child ; China ; Clarithromycin ; pharmacology ; Clindamycin ; pharmacology ; Drug Resistance, Multiple, Bacterial ; genetics ; Erythromycin ; pharmacology ; Genotype ; Humans ; Macrolides ; pharmacology ; Microbial Sensitivity Tests ; Penicillins ; pharmacology ; Phenotype ; Spiramycin ; analogs & derivatives ; pharmacology ; Streptococcal Infections ; genetics ; microbiology ; Streptococcus pneumoniae ; drug effects ; genetics ; isolation & purification