SEARCH · PubMed Health

Results for “Azithromycin”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,495 records · Page 83Linked to original sources

PubMed2006

Reduced ability of penicillin to eradicate ingested group A streptococci from epithelial cells: clinical and pathogenetic implications.

BACKGROUND: Group A streptococci (Streptococcus pyogenes; GAS) invades human epithelial cell lines. Failure of penicillin to eradicate GAS from the throats of patients, especially those who are GAS "carriers," has been increasingly reported. However, there has been no comprehensive evaluation of how effectively antibiotics that are used to treat GAS enter upper respiratory tract epithelial cells and kill internalized GAS. We examined the viability of ingested, intracellular GAS after epithelial cell exposure to antibiotics commonly recommended for therapy of GAS infections. METHODS: A human laryngeal epithelial cell line (HEp-2) was used. Three techniques were used to study antibiotic (penicillin V, erythromycin, azithromycin, cephalothin, and clindamycin) killing of ingested GAS: examination by electron microscopy of ultrathin sections of ingested GAS, qualitative determination of intra-epithelial cell antibiotic, and special stain evaluation of intracellular GAS viability after epithelial cell exposure to antibiotics. RESULTS: GAS survived intracellularly despite exposure of the GAS-containing epithelial cells to penicillin. In contrast, there was killing of ingested GAS after exposure of epithelial cells to either erythromycin or azithromycin. Electron microscopy confirmed a lack of intracellular GAS fragmentation (cell death) after exposure of epithelial cells to penicillin in contrast to obvious GAS fragmentation after epithelial cell exposure to erythromycin or azithromycin. Cephalothin, a cephalosporin, and clindamycin were more effective in killing ingested GAS than was penicillin, but they were less effective than erythromycin or azithromycin. CONCLUSIONS: These observations strongly suggest that if the GAS upper respiratory tract carrier state results from intra-epithelial cell GAS survival, the failure of penicillin to kill ingested GAS may be related to a lack of effective penicillin entry into epithelial cells. These unique observations may have clinical implications for understanding GAS respiratory tract carriers and managing GAS infections.

Anti-Bacterial Agents↗

PubMed1998

Prevention of experimental Haemophilus ducreyi infection: a randomized, controlled clinical trial.

Human subjects were infected with Haemophilus ducreyi. All subjects developed papules and were randomized to treatment with a single dose of azithromycin (1 g) or ciprofloxacin (500 mg). At weekly intervals, volunteers were reinoculated with H. ducreyi, and drug concentrations were measured in peripheral blood mononuclear cells (PBMC). When papules developed, the subjects were treated with antibiotics and dismissed from the study. Eight of the ciprofloxacin-treated subjects developed papules 1 week after the initial treatment, and the ninth subject developed disease 2 weeks after treatment. The 9 azithromycin-treated subjects developed papules 4-10 weeks (mean, 6.8) after the initial treatment (P < .001). Azithromycin was detected in PBMC for 3-6 weeks (mean, 4). Pre- and posttreatment lesions had histology typical of experimental chancroid or were culture positive. Azithromycin prevents experimental chancroid for nearly 2 months. These findings have implications for strategies to prevent chancroid.

Adult↗

PubMed1996

Cytotoxicity of macrolide antibiotics in a cultured human liver cell line.

Cytotoxicity of erythromycin base, erythromycin estolate, erythromycin-11,12-cyclic carbonate, roxithromycin, clarithromycin and azithromycin was compared in cultured human non-malignant Chang liver cells using reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide and cellular protein concentration as end points of toxicity. Erythromycin estolate was the most toxic macrolide in all tests differing clearly from all the other macrolides studied. Erythromycin-11,12-cyclic carbonate was also more toxic than the other macrolides. Roxithromycin and clarithromycin were the next toxic derivatives, while erythromycin base and azithromycin were least toxic. Thus, cytotoxicity of the new semisynthetic macrolides, roxithromycin, clarithromycin and azithromycin, is not substantially different from that of erythromycin base. In view of the low level of hepatotoxicity of macrolides hitherto reported in humans, the results do not suggest any substantial risk for hepatic disorders related to the use of azithromycin, clarithromycin and roxithromycin.

Anti-Bacterial Agents↗

PubMed2002

Intracellular activity of ABT-773 and other antimicrobial agents against Legionella pneumophila.

The intracellular activity of ABT-773 against Legionella pneumophila was compared with azithromycin and ciprofloxacin using HL-60 cells. Against L. pneumophila ATCC 33152 and three clinical isolates the MICs (mg/L) were ABT-773 0.015, ciprofloxacin 0.03 and azithromycin 0.03. At 48 h, the mean percentage inhibition was as follows: 28.5 +/- 5.9% and 32.6 +/- 4.6% at 8 x and 16 x MIC of ABT-773; 38.1 +/- 8.6% and 48.2 +/- 7.0% at 8 x and 16 x MIC of ciprofloxacin; and 26.3 +/- 9.9% and 28.5 +/- 9.9% at 8 x and 16 x MIC of azithromycin. In this study, all three agents were highly active, with ABT-773 demonstrating similar activity to azithromycin against L. pneumophila.

Anti-Bacterial Agents↗

PubMed2005

In vitro activity of pazufloxacin, tosufloxacin and other quinolones against Legionella species.

OBJECTIVES: The activities of pazufloxacin and tosufloxacin against Legionella spp. were evaluated in vitro and compared with those of other quinolones, macrolides and azithromycin. METHODS: The conventional MICs were determined by the microbroth dilution method. Intracellular activities of drugs were evaluated by a cfu count. The minimal extracellular concentration inhibiting intracellular growth of bacteria (MIEC) was determined by a colorimetric cytopathic assay. RESULTS: MICs of pazuloxacin and tosufloxacin at which 90% (MIC90) of isolates are inhibited in 76 different Legionella spp. strains (38 ATCC strains and 38 clinical isolates) were 0.032 and 0.016 mg/L, whereas the MIC90s of levofloxacin, ciprofloxacin, garenoxacin, erythromycin, clarithromycin and azithromycin were 0.032, 0.032, 0.032, 2.0, 0.125 and 2.0 mg/L, respectively. Pazufloxacin and tosufloxacin at 4x MIC inhibited intracellular growth of Legionella pneumophila SG1 (80-045 strain), as did other quinolones, clarithromycin and azithromycin, whereas erythromycin at 4x MIC did not. MIECs of pazufloxacin, tosufloxacin, levofloxacin, ciprofloxacin and garenoxacin for the strain were 0.063, 0.004, 0.016, 0.032 and 0.008 mg/L respectively, which were superior to those of macrolides and azithromycin. Pazufloxacin showed potent activity against three additional clinical isolates of L. pneumophila SG1, one clinical isolate each of L. pneumophila SG3 and SG5, as well as Legionella micdadei, Legionella dumoffii and Legionella longbeachae SG1. CONCLUSIONS: Pazufloxacin and tosufloxacin, as well as other quinolones, were more potent than macrolides and an azalide. Present data warrant further study on the efficacy of these drugs in the treatment of Legionella infections.

Animals↗

PubMed2006

A pharmacodynamic approach to antimicrobial activity in serum and epithelial lining fluid against in vivo-selected Streptococcus pneumoniae mutants and association with clinical failure in pneumonia.

OBJECTIVES: Emergence of resistance may be prevented by killing both the parental infecting strain and subsequent less susceptible step-mutants. The present study analyses eradication and resistance selection in Streptococcus pneumoniae with moxifloxacin, levofloxacin and azithromycin, using a parental serotype 3 clinical strain (strain A) and its correspondent step-mutant derivatives resistant to these antibiotics (B, C, D), which were selected in vivo in a patient with pneumonia. METHODS: Moxifloxacin, levofloxacin and azithromycin MICs were 1, 2 and 0.5 mg/L for the parental strain; 4, 16 and 4 mg/L for isolate B; and 4, 16 and >128 mg/L for isolates C and D, respectively. A pharmacokinetic computerized device was used to simulate serum and epithelial lining fluid (ELF) concentrations. Initial inoculum was approximately 10(8) cfu/mL. Population analysis profiles were performed using plates with increasing antimicrobial concentrations. RESULTS: In ELF simulations, moxifloxacin showed a bactericidal pattern against all isolates with a minority (approximately 100 cfu/mL) of the surviving population (isolates B, C and D) growing on plates with moxifloxacin concentrations just above those in ELF. Levofloxacin and azithromycin showed a bactericidal pattern only against isolate A, with the whole population of isolates B, C and D growing on plates with levofloxacin concentrations higher (16-64 mg/L) than those in ELF and in plates with azithromycin concentrations as high as 2048 mg/L (for isolates C and D). CONCLUSIONS: Antimicrobial activity in pulmonary tissue against possible emerging resistant mutants during pneumonia treatment may prevent failures more than the solely activity against the S. pneumoniae parental infecting strain.

Anti-Bacterial Agents↗

PubMed2002

Elimination of blinding trachoma.

PURPOSE OF REVIEW: A recently initiated major effort to eliminate blinding trachoma as a public health problem is discussed. RECENT FINDINGS: Mass (community-wide) treatment with a short course of oral azithromycin has been shown to be at least as effective as long courses (42 doses over a 6-week period) of topical tetracycline in reducing clinically active trachoma and the prevalence of chlamydial infection. The beneficial effects last for more than a year, in contrast to the short-lived results typically seen after previous control programs that used topical therapy. Azithromycin is a key element in the integrated approach towards eliminating blinding trachoma summarized as the 'SAFE' strategy (surgery for deformed eyelids; antibiotic treatment of whole communities with azithromycin, to control infection; face washing and improved hygiene of young children; and environmental improvements, particularly the provision of water and latrines). The first regional application of this strategy has shown dramatic results, producing a reduction in trachoma activity of more than 70% in Morocco. SUMMARY: The goal of eliminating blinding trachoma may be reachable. Further research is needed to determine how best to use azithromycin and which environmental improvements will be most effective. The important questions are as follows: how often antibiotic treatment programs will be required in the endemic areas; how best to evaluate the effects of treatment; and when (and perhaps whom) do we retreat.

Anti-Bacterial Agents↗

PubMed1998

Preventing Mycobacterium avium complex in patients who are using protease inhibitors: a cost-effectiveness analysis.

BACKGROUND: Practice guidelines recommending Mycobacterium avium complex (MAC) prophylaxis for patients with HIV disease were based on clinical trials in which individuals did not receive protease inhibitors. OBJECTIVE: To estimate the cost-effectiveness of strategies for MAC prophylaxis in patients whose treatment regimen includes protease inhibitors. DESIGN: Decision analysis with Markov modelling of the natural history of advanced HIV disease. Five strategies were evaluated: no prophylaxis, azithromycin, rifabutin, clarithromycin and a combination of azithromycin plus rifabutin. MAIN OUTCOME MEASURES: Survival, quality of life, quality-adjusted survival, health care costs and marginal cost-effectiveness ratios. RESULTS: Compared with no prophylaxis, rifabutin increased life expectancy from 78 to 80 months, increased quality-adjusted life expectancy from 50 to 52 quality-adjusted months and increased health care costs from $233000 to $239800. Ignoring time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $44300 per life year. Adjusting for time discounting and quality of life, the cost-effectiveness of rifabutin relative to no prophylaxis was $41500 per quality-adjusted life year (QALY). In comparison with rifabutin, azithromycin was associated with increased survival, increased costs and an incremental cost-effectiveness ratio of $54300 per QALY. In sensitivity analyses, prophylaxis remained economically attractive unless the lifetime chance of being diagnosed with MAC was less than 20%, the rate of CD4 count decline was less than 10 x 10(6) cells/l per year, or the CD4 count was greater than 50 x 10(6) cells/l. CONCLUSION: MAC prophylaxis increases quality-adjusted survival at a reasonable cost, even in patients using protease inhibitors. When not contraindicated, starting azithromycin or rifabutin when the patient's CD4 count is between 50 and 75 x 10(6) cells/l is the most cost-effective strategy. The main determinants of cost-effectiveness are CD4 count, viral load, place of residence and patient preference.

AIDS-Related Opportunistic Infections↗

PubMed2001

Antimicrobial susceptibility of Neisseria gonorrhoeae isolates from three Caribbean countries: Trinidad, Guyana, and St. Vincent.

BACKGROUND: The percentage of Neisseria gonorrhoeae isolates resistant to antimicrobial agents commonly used for treatment is unknown in many Caribbean countries. GOAL: To determine the antimicrobial susceptibility of N gonorrhoeae isolates from Trinidad (144 isolates), Guyana (70 isolates), and St. Vincent (68 isolates) so baseline data can be established for further studies, and to assist in establishing effective treatment guidelines. STUDY DESIGN: Consecutive urethral and endocervical specimens from several clinics were collected and identified as N gonorrhoeae. Isolates of N gonorrhoeae were tested for their susceptibility to penicillin, tetracycline, ceftriaxone, ciprofloxacin, spectinomycin, and azithromycin. The presumptive identification of penicillinase-producing N gonorrhoeae and/or tetracycline-resistant N gonorrhoeae isolates based on MIC was confirmed by plasmid and tetM content analysis. RESULTS: High percentages of penicillin and/or tetracycline resistance were observed in N gonorrhoeae isolates from Guyana (92.9%), St. Vincent (44.1%), and Trinidad (42.4%). Isolates from all three countries were susceptible to ceftriaxone, ciprofloxacin, and spectinomycin. One penicillinase-producing N gonorrhoeae/tetracycline-resistant N gonorrhoeae from Guyana had an MIC of 0.5 microg/l to ciprofloxacin. This and nine other isolates from Guyana also were resistant to azithromycin (defined as MIC > or = 2.0 microg/ml) as well as penicillin and tetracycline. A reduced susceptibility to azithromycin was displayed by 16% of the isolates from St. Vincent and 72% of the isolates from Guyana (MIC, 0.25-1.0 microg/ml). Most penicillinase-producing N gonorrhoeae isolates carried Africa-type plasmids (61/90), with 28 of 90 having Toronto-type plasmids and a single isolate carrying an Asia-type plasmid. The tetM determinant in tetracycline-resistant N gonorrhoeae isolates was predominantly of the Dutch type (68/91). CONCLUSIONS: The high prevalence of N gonorrhoeae isolates from 3 of 21 English- and Dutch-speaking Caricom countries in the Caribbean with either plasmid-mediated or chromosomal resistance to penicillin and tetracycline supports international observations that these drugs should not be used to treat gonococcal infections. The detection of isolates with reduced susceptibility to drugs such as azithromycin, which currently are recommended for treatment in the region, attest to the importance of the continued monitoring of gonococcal antimicrobial susceptibility for the maintenance of effective treatment guidelines.

Anti-Bacterial Agents↗

PubMed2006

Antipneumococcal activity of DW-224a, a new quinolone, compared to those of eight other agents.

DW-224a is a new broad-spectrum quinolone with excellent antipneumococcal activity. Agar dilution MIC was used to test the activity of DW-224a compared to those of penicillin, ciprofloxacin, levofloxacin, gatifloxacin, moxifloxacin, gemifloxacin, amoxicillin-clavulanate, cefuroxime, and azithromycin against 353 quinolone-susceptible pneumococci. The MICs of 29 quinolone-resistant pneumococci with defined quinolone resistance mechanisms against seven quinolones and an efflux mechanism were also tested. DW-224a was the most potent quinolone against quinolone-susceptible pneumococci (MIC(50), 0.016 microg/ml; MIC(90), 0.03 microg/ml), followed by gemifloxacin, moxifloxacin, gatifloxacin, levofloxacin, and ciprofloxacin. beta-Lactam MICs rose with those of penicillin G, and azithromycin resistance was seen mainly in strains with raised penicillin G MICs. Against the 29 quinolone-resistant strains, DW-224a had the lowest MICs (0.06 to 1 microg/ml) compared to those of gemifloxacin, clinafloxacin, moxifloxacin, gatifloxacin, levofloxacin, and ciprofloxacin. DW-224a at 2x MIC was bactericidal after 24 h against eight of nine strains tested. Other quinolones gave similar kill kinetics relative to higher MICs. Serial passages of nine strains in the presence of sub-MIC concentrations of DW-224a, moxifloxacin, levofloxacin, ciprofloxacin, gatifloxacin, gemifloxacin, amoxicillin-clavulanate, cefuroxime, and azithromycin were performed. DW-224a yielded resistant clones similar to moxifloxacin and gemifloxacin but also yielded lower MICs. Azithromycin selected resistant clones in three of the five parents tested. Amoxicillin-clavulanate and cefuroxime did not yield resistant clones after 50 days.

Amoxicillin-Potassium Clavulanate Combination↗

PubMed1996

New pharmacokinetic in vitro model for studies of antibiotic activity against intracellular microorganisms.

The capacity for intracellular growth is an important survival strategy for a large group of common pathogens. Helicobacter pylori, the etiological agent for gastritis and duodenal ulcer, has been shown by both in vivo and in vitro studies to have the capacity to invade epithelial cells. In vitro models are used to study the effect of antibiotics on microoganisms. Most investigations are performed in broth culture or on agar plates, but kinetic models for bacteria in broth have been described. We present a new, kinetic model adapted for intracellular pathogens. A glass chamber, with a metal rack fitting Falcon cell culture inserts, was connected to a pump by rubber tubes. Different tube diameters and pump speeds were evaluated, and the assay was designed to mimic the half-lives of the antibiotics in vivo, i.e., 11.5 h for azithromycin, 5 h for clarithromycin, and 1 h for amoxicillin. Monolayers of HEp-2 cells were grown in the inserts for 2 days, after which H. pylori (clinical strain 88-23), was added to the system. Internalization was allowed for 12 h, and extracellular H. pylori cells were eradicated with gentamicin. The inserts were moved to the glass chamber, containing medium with 12.5 mg of either amoxicillin or azithromycin per liter or 2.4 mg of clarithromycin per liter. This represents 12.5, 50, and 80 times the extracellular minimum bactericidal concentration value, respectively. Samples were taken at 0, 2, 4, 6, 8, and 24 h. The HEp-2 cells were lysed, and intracellular bacteria were counted by plating. Inserts with infected cells grown in drug-free medium were included as controls for each time interval. A 3-log10 reduction of H. pylori was achieved in the experiments with azithromycin, and a 4-log10 reduction was achieved in the clarithromycin experiments, while no intracellular effect was seen when amoxicillin was used. The antibiotic concentrations at the sampling intervals were 12.5, 3.1, 0.8, 0.2, 0.05, and 0 mg/liter for amoxicillin; 12.5, 11.5, 10, 9, 8, and 3 mg/liter for azithromycin; and 2.4, 1.8, 1.4, 1, 0.8, and 0 mg/liter for clarithromycin. This new model for pharmacokinetic studies provides a useful tool, with applications for a broad range of microorganisms.

Amoxicillin↗

PubMed1999

Mechanism of the intracellular killing and modulation of antibiotic susceptibility of Listeria monocytogenes in THP-1 macrophages activated by gamma interferon.

Listeria monocytogenes, a facultative intracellular pathogen, readily enters cells and multiplies in the cytosol after escaping from phagosomal vacuoles. Macrophages exposed to gamma interferon, one of the main cellular host defenses against Listeria, become nonpermissive for bacterial growth while containing Listeria in the phagosomes. Using the human myelomonocytic cell line THP-1, we show that the combination of L-monomethyl arginine and catalase restores bacterial growth without affecting the phagosomal containment of Listeria. A previous report (B. Scorneaux, Y. Ouadrhiri, G. Anzalone, and P. M. Tulkens, Antimicrob. Agents Chemother. 40:1225-1230, 1996) showed that intracellular Listeria was almost equally sensitive to ampicillin, azithromycin, and sparfloxacin in control cells but became insensitive to ampicillin and more sensitive to azithromycin and sparfloxacin in gamma interferon-treated cells. We show here that these modulations of antibiotic activity are largely counteracted by L-monomethyl arginine and catalase. In parallel, we show that gamma interferon enhances the cellular accumulation of azithromycin and sparfloxacin, an effect which is not reversed by addition of L-monomethyl arginine and catalase and which therefore cannot account for the increased activity of these antibiotics in gamma interferon-treated cells. We conclude that (i) the control exerted by gamma interferon on intracellular multiplication of Listeria in THP-1 macrophages is dependent on the production of nitric oxide and hydrogen peroxide; (ii) intracellular Listeria may become insensitive to ampicillin in macrophages exposed to gamma interferon because the increase in reactive oxygen and nitrogen intermediates already controls bacterial growth; and (iii) azithromycin and still more sparfloxacin cooperate efficiently with gamma interferon, one of the main cellular host defenses in Listeria infection.

Ampicillin↗

PubMed2003

Effects of an efflux mechanism and ribosomal mutations on macrolide susceptibility of Haemophilus influenzae clinical isolates.

This study investigated macrolide resistance mechanisms in clinical Haemophilus influenzae strains with different levels of susceptibility to macrolides. A total of 6,382 isolates were collected during the Alexander Project from 1997 to 2000. For 96.9% of these isolates, the azithromycin MICs were 0.25 to 4 micro g/ml, and these were defined as baseline strains. For 1.8% of the isolates, the azithromycin MICs were lower (<0.25 micro g/ml), and for 1.3% of the isolates, the MICs were higher (>4 micro g/ml). These isolates were defined as hypersusceptible and high-level macrolide-resistant strains, respectively. To identify the mechanisms associated with these three susceptibility patterns, representative strains were studied for the presence of macrolide efflux pumps and for ribosomal alterations. Macrolide efflux was studied by measuring the accumulation of radioactive azithromycin and clarithromycin in the presence or absence of carbonyl cyanide m-chlorophenylhydrazone (CCCP), a protonophore. Treatment with CCCP increased the accumulation of macrolides in baseline as well as high-level resistant strains, demonstrating the presence of an efflux mechanism, but not in the 20 hypersusceptible strains tested. Among the 31 strains studied that showed high-level resistance to both azithromycin and clarithromycin, 28 had ribosomal alterations, 7 had mutations in ribosomal protein L4, 11 had mutations in L22, 2 had mutations in 23S rRNA, 8 had multiple mutations, and 3 had no mutations. From these results, we conclude that the vast majority (>98%) of H. influenzae strains have a macrolide efflux mechanism, with a few of these being hyperresistant (1.3%) due to one or several ribosomal mutations. Occasional hypersusceptible strains (1.8%) were found and had no macrolide resistance mechanisms and appeared to be the only truly macrolide-susceptible variants of H. influenzae.

Anti-Bacterial Agents↗

PubMed2005

Bactericidal activity of first-choice antibiotics against gamma interferon-induced persistent infection of human epithelial cells by Chlamydia trachomatis.

Chlamydia trachomatis is responsible for clinically important chronic inflammatory diseases of humans, including trachoma and pelvic inflammatory disease. Persistent infection of mucosal sites may contribute to the development of these chronic inflammatory diseases. Standard clinical therapy results in satisfactory cure rates of acute infections; however, chronic infection associated with persistence has been suggested to be less responsive to antibiotic therapy. We report the efficiency of two first-line chlamydial antibiotics, azithromycin and doxycycline, under conditions of eradication of C. trachomatis persistent infection using the in vitro model of gamma interferon (IFN-gamma)-mediated persistence and reactivation from persistence. Doxycycline was superior in eradicating acute (minimal bactericidal concentration [MBC](100) = 2.5 to 5.0 microg/ml) compared to persistent (MBC(100) = 10 to 50 mirog/ml) infection. In contrast, azithromycin was significantly more effective in eradicating persistent infection (MBC(100) = 2.5 to 5.0 microg/ml) than acute infection (MBC(100) = 10 to 50 microg/ml). The superior bactericidal effect of azithromycin against persistent infection was found to correlate with the enhanced uptake of the drug by IFN-gamma-treated infected epithelial cells. Based on these findings, we hypothesize that azithromycin should be a particularly efficacious anti-infective agent for the eradication of IFN-gamma-induced chlamydial persistent infection in vivo.

Anti-Bacterial Agents↗

PubMed1996

Chlamydial cervicitis and urethritis: single dose treatment compared with doxycycline for seven days in community based practises.

STUDY GOAL: To compare the efficacy and safety of single 1 g oral azithromycin with doxycycline, 100 mg twice daily for seven days for treatment of uncomplicated urogenital chlamydial infection. STUDY DESIGN: Randomised, unblinded, comparative trial, involving 597 patients demonstrating clinical evidence of genital chlamydia and a positive non-culture assay for Chlamydia trachomatis. RESULTS: Among the azithromycin- and doxycycline-treated patients 61% and 60%, respectively, were asymptomatic within one week after the first dose. At two weeks, these figures increased to 86% and 83%, respectively. Bacteriological eradication, based on a negative assay, occurred in 338 (97%) of 347 azithromycin-treated patients and 161 (99%) of 163 doxycycline-treated patients. CONCLUSION: Treatment of uncomplicated chlamydial cervicitis and urethritis with single 1 g oral azithromycin is equivalent to standard therapy with doxycycline. Drug-related adverse events were approximately twice as common as previously reported for both drugs.

Adolescent↗

PubMedDate not supplied

[Treatment for Legionnaires' disease. Macrolides or quinolones?].

BACKGROUND: Macrolides and fluoroquinolones are the recommended treatment for Legionnaires' disease. The aim of our study was to analyze the clinical efficacy of clarithromycin, azithromycin and levofloxacin in patients with Legionnaires' disease. METHODS: Prospective, observational study involving all adult patients with Legionella pneumophila pneumonia attended at Hospital Universitario Vall d'Hebron (Barcelona, Spain) from January 2001 to December 2004. Duration of fever, length of hospital stay and mortality were compared among 52 patients treated with clarithromycin, 43 with azithromycin and 18 with levofloxacin. RESULTS: The proportion of patients with risk factors for Legionnaires' disease, the initial severity of the pneumonia and the number of patients who required intensive care unit admission were similar in patients treated with clarithromycin, azithromycin and levofloxacin. In-hospital mortality was 5.3%. There were no significant differences in fever duration, length of hospital stay or mortality among the 3 groups of patients. CONCLUSION: In our experience, clarithromycin, azithromycin and levofloxacin were all efficacious for the treatment of Legionnaires' disease.

Adult↗

PubMedDate not supplied

Evaluation of different antibiotics in inhibiting colonization of Vibrio cholerae O1 and O139 in the rabbit intestine.

The effects of furazolidone, erythromycin and azithromycin in inhibiting colonisation of Vibrio cholerae O1 and O139 in the rabbit intestine were tested. Both V. cholerae O1 and O139 highly colonised the gut in control rabbits. The colonisation of furazolidone-resistant strains in the rabbit intestine was prevented effectively by both erythromycin and azithromycin. In furazolidone-sensitive strains, the efficacies of erythromycin and azithromycin were very much comparable to furazolidone. These results suggested that azithromycin may be subjected to clinical trial in comparison to furazolidone and erythromycin for the treatment of cholera due to O1 and O139 infection in children.

Animals↗

PubMed1995

Inhibition of cytoplasmic and organellar protein synthesis in Toxoplasma gondii. Implications for the target of macrolide antibiotics.

We investigated potential targets for the activity of protein synthesis inhibitors against the protozoan parasite Toxoplasma gondii. Although nanomolar concentrations of azithromycin and clindamycin prevent replication of T. gondii in both cell culture and in vivo assays, no inhibition of protein labeling was observed in either extracellular or intracellular parasites treated with up to 100 microM drug for up to 24 h. Quantitative analysis of > 300 individual spots on two-dimensional gels revealed no proteins selectively depleted by 100 microM azithromycin. In contrast, cycloheximide inhibited protein synthesis in a dose-dependent manner. Nucleotide sequence analysis of the peptidyl transferase region from genes encoding the large subunit of the parasite's ribosomal RNA predict that the cytoplasmic ribosomes of T. gondii, like other eukaryotic ribosomes, should be resistant to macrolide antibiotics. Combining cycloheximide treatment with two-dimensional gel analysis revealed a small subset of parasite proteins likely to be synthesized on mitochondrial ribosomes. Synthesis of these proteins was inhibited by 100 microM tetracycline, but not by 100 microM azithromycin or clindamycin. Ribosomal DNA sequences believed to be derived from the T. gondii mitochondrial genome predict macrolide/lincosamide resistance. PCR amplification of total T. gondii DNA identified an additional class of prokaryotic-type ribosomal genes, similar to the plastid-like ribosomal genes of the Plasmodium falciparum. Ribosomes encoded by these genes are predicted to be sensitive to the lincosamide/macrolide class of antibiotics, and may serve as the functional target for azithromycin, clindamycin, and other protein synthesis inhibitors in Toxoplasma and related parasites.

Animals↗