Activity of telithromycin and seven other agents against 1034 pediatric Streptococcus pneumoniae isolates from ten central and eastern European centers

Objective  To test the activity of telithromycin against 1034 Streptococcus pneumoniae isolates from pediatric patients in ten centers from ten central and eastern European countries during 2000–2001, and to compare it with the activities of erythromycin A, azithromycin, clarithromycin, clindamycin, and quinupristin–dalfopristin.
Methods  The minimum inhibitory concentrations (MICs) of telithromycin, erythromycin A, azithromycin, clarithromycin, clindamycin, levofloxacin, quinupristin–dalfopristin and penicillin G were tested by the agar dilution method with incubation in air, and mechanisms of resistance to macrolides and quinolones were investigated.
Results  Strains were isolated from sputum, tracheal aspirates, ear, eye, blood, and cerebrospinal fluid. Among S. pneumoniae strains tested, 36% had raised penicillin G MICs (≥ 0.12 mg/L). Susceptibilities were as follows: telithromycin, quinupristin–dalfopristin and levofloxacin, ≥ 99%; clindamycin, 83%; and erythromycin A, azithromycin and clarithromycin, 78%. Of 230 (22.3%) erythromycin A-resistant S. pneumoniae strains, 176 (79.6%) had erm(B) , 38 (16.1%) had mef(A) , and 10 (4.3%) had mutations in 23S ribosomal RNA or in ribosomal protein L4. The rates of drug-resistant S. pneumoniae are high in all centers except Kaunas, Riga, and Prague.
Conclusion  Telithromycin had low MICs against all strains, irrespective of macrolide, azalide or clindamycin resistance. Ribosomal methylation was the most prevalent resistance mechanism among all resistant strains, except in Sofia, where the prevalence of the efflux mechanism was higher.     

4-[4-(吡啶-3-基)咪唑-1-基]丁胺的合成

以3-乙酰基吡啶为起始原料,经肟化、磺酰化、氧化、环合、还原得到3-(咪唑-4-基)吡啶,再经与N-(4-溴丁基)邻苯二甲酰亚胺缩合及肼解等反应制得抗菌剂泰利霉素的特定侧链化合物4-[4-(吡啶-3-基)咪唑-1-基]丁胺,总收率24%.     

Involvement of intestinal permeability in the oral absorption of clarithromycin and telithromycin

The involvement of intestinal permeability in the oral absorption of clarithromycin (CAM), a macrolide antibiotic, and telithromycin (TEL), a ketolide antibiotic, in the presence of efflux transporters was examined. In order independently to examine the intestinal and hepatic availability, CAM and TEL (10 mg/kg) were administered orally, intraportally and intravenously to rats. The intestinal and hepatic availability was calculated from the area under the plasma concentration–time curve (AUC) after administration of CAM and TEL via different routes. The intestinal availabilities of CAM and TEL were lower than their hepatic availabilities. The intestinal availability after oral administration of CAM and TEL increased by 1.3‐ and 1.6‐fold, respectively, after concomitant oral administration of verapamil as a P‐glycoprotein (P‐gp) inhibitor. Further, an in vitro transport experiment was performed using Caco‐2 cell monolayers as a model of intestinal epithelial cells. The apical‐to‐basolateral transport of CAM and TEL through the Caco‐2 cell monolayers was lower than their basolateral‐to‐apical transport. Verapamil and bromosulfophthalein as a multidrug resistance‐associated proteins (MRPs) inhibitor significantly increased the apical‐to‐basolateral transport of CAM and TEL. Thus, the results suggest that oral absorption of CAM and TEL is dependent on intestinal permeability that may be limited by P‐gp and MRPs on the intestinal epithelial cells. Copyright © 2014 John Wiley & Sons, Ltd.     

Desmethyl Macrolides: Synthesis and Evaluation of 4-Desmethyl Telithromycin

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Controlling acute bacterial maxillary sinusitis

In acute maxillary sinusitis, after an initial viral episode, bacterial infection can be demonstrated using specific investigations and bacterial isolation. In the vast majority of cases, however, the diagnosis is presumptive. Symptomatic treatments tend to reduce pain and inflammation for easier pus drainage. The decision for or against antibiotic therapy continues to be a matter of debate. Many antibiotics have been used but modern guidelines have established recommendations for the choice and duration of treatments, based on (i) knowledge of pathogens and of their resistance profiles; (ii) improved understanding of the pharmacology of antibiotics, guiding doses and administration routes; (iii) comparative double-blind studies, evaluating antibiotics versus placebo and β-lactams versus macrolides. Use of newer drugs (fluoroquinolones, ketolides) must be discussed in terms of cost and efficacy.     

Changing Pattern of Relapse in Osteosarcoma of the Extremities Treated with Adjuvant and Neoadjuvant Chemotherapy

Abstract

In 551 patients with osteosarcoma of the extremities treated between 1980 and 1991 in our Institution with surgery only (35 cases), surgery combined with adjuvant chemotherapy (147 cases) or neoadjuvant chemotherapy (369 cases) the relapse patterns were analyzed. Adjuvant chemotherapy was performed according to 2 different protocols and neoadjuvant chemotherapy according to 3 different protocols successively activated.

In the 252 patients who relapsed, the interval between initial treatment and first relapse was significantly longer in the group treated with adjuvant and neoadjuvant chemotherapy (18.1 and 21.3 mo) than in the group treated with surgery only (5.4 mo). For patients treated with neoadjuvant chemotherapy, a longer interval was seen in the most effective regimen of neoadjuvant chemotherapy (25 mo). No significant differences were seen among the 3 groups, according to the site of first metastasis, although in patients treated with the most effective neoadjuvant regimen there was a higher incidence of bone metastasis.

In patients who relapsed with pulmonary metastases the average number of nodules seen by standard X-rays, as well as CT scans, was significantly higher in patients treated with surgery only (3.6) than in patients treated with adjuvant or neoadjuvant chemotherapy (2.5 and 2.6 nodules).

We conclude that these changes in metastatic pattern in patients treated with adjuvant and neoadjuvant chemotherapy are important, because they may encourage the use of salvage therapy with thoracotomy in a larger number of patients.

Prolongation of time relapsed after more effective regimens of adjuvant and neoadjuvant chemotherapy should be considered when evaluating the preliminary results of new chemotherapy protocols.     

Desmethyl Macrolide Analogues to Address Antibiotic Resistance: Total Synthesis and Biological Evaluation of 4,8,10-Tridesmethyl Telithromycin

There is an urgent need to discover new drugs to address the pressing problem of antibiotic-resistance. Macrolide antibiotics such as erythromycin (1) are safe, broad-spectrum antibiotics used in the clinic since 1954. Herein we report the synthesis and evaluation of 4,8,10-tridesmethyl telithromycin (3), a novel desmethyl analogue of the 3rd-generation drug telithromycin (2), which is a semisynthetic derivative of 1. Analogue 3 was found to possess antibiotic activity and was superior to telithromycin (2) when tested against resistant strains of S. aureus possessing an A→T mutation at position 2058 (E. coli numbering).     

In vitro activities of oral cephem and telithromycin against clinical isolates of major respiratory pathogens in Japan

The in vitro antibacterial activities of oral cephem antibiotics and ketolide telithromycin against major respiratory pathogens possessing beta-lactam-resistant mutations (within the pbp gene) and/or macrolide-resistant genes (erm and mef) were examined in clinical isolates collected at 66 institutes in all over the Japan between 2002 and 2003. Telithromycin showed the strongest antibacterial activity against methicillinsusceptible Staphylococcus aureus strains with and without macrolide-resistant genes, such as ermA or ermC gene. All the cephem antibiotics showed potent antibacterial activity against Streptococcus pyogenes, with minimum inhibitory concentrations (MICs) of 0.015 mg/L or lower. Cefdinir had a much higher MIC90 against genotypic penicillin-resistant Streptococcus pneumoniae (gPRSP) than cefditoren and cefcapene (8 mg/L cefdinir vs. 1 mg/L cefditoren and cefcapene). The majority of gPRSP harbored either ermB or mefA, and the antibacterial activity of telithromycin against these strains was decreased however some susceptibility was still sustained. Cefditoren exerted the strongest antibacterial activity against beta-lactamase-negative ampicillin-resistant Haemophilus influenzae, with an MIC90 of 0.5 mg/L. These results underline the importance of checking the susceptibility and selecting an appropriate antibiotic against target pathogens.     

Telithromycin versus clarithromycin for the treatment of community-acquired respiratory tract infections: a meta-analysis of randomized controlled trials

Background The emergence of bacterial resistance to commonly used antibiotics,such as macrolides,is complicating the management of respiratory tract infections (RTIs).Telithromycin,a ketolide antimicro...     

Novel antibacterial agents for the treatment of serious Gram-positive infections

With the continuing development of clinical drug resistance among bacteria and the advent of resistance to the recently released agents quinupristin-dalfopristin and linezolid, the need for new, effective agents to treat multi-drug-resistant Gram-positive infections remains important. This review focuses on agents presently in clinical development for the treatment of serious multidrug-resistant staphylococcal, enterococcal and pneumococcal infections, including methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci and penicillin-resistant Streptococcus pneumoniae. Agents to be discussed that affect the prokaryotic cell wall include the antimethicillin-resistant S. aureus cephalosporins BAL9141 and RWJ-54428, the glycopeptides oritavancin and dalbavancin and the lipopeptide daptomycin. Topoisomerase inhibitors include the fluoroquinolones gemifloxacin, sitafloxacin and garenoxacin. Protein synthesis inhibitors are represented by the ketolides telithromycin and cethromycin, the oxazolidinones and the glycylcycline tigecycline. Although each of these compounds has demonstrated antibacterial activity against antibiotic-resistant pathogens, their final regulatory approval will depend on an acceptable clinical safety profile.