PubMed Health⌕ Search

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 1,585 records · Page 88Linked to original sources

Oxyrase, a method which avoids CO2 in the incubation atmosphere for anaerobic susceptibility testing of antibiotics affected by CO2.

The Oxyrase agar dilution method, with exclusion of CO2 from the environment, was compared with the reference agar dilution method recommended by the National Committee for Clinical Laboratory Standards (anaerobic chamber with 10% CO2) to test the susceptibility of 51 gram-negative and 43 gram-positive anaerobes to azithromycin and erythromycin. With the Oxyrase method, anaerobiosis was achieved by incorporation of the O2-binding enzyme Oxyrase in addition to susceptibility test medium, antibiotic, and enzyme substrates into the upper level of a biplate. Plates were covered with a Brewer lid and incubated in ambient air. With azithromycin, Oxyrase yielded an MIC for 50% of strains tested (MIC50) and MIC90 of 2.0 and 8.0 micrograms/ml, compared to 8.0 and > 32.0 micrograms/ml in standard anaerobic conditions. At a breakpoint of 8.0 micrograms/ml, 90.4% of strains were susceptible to azithromycin with Oxyrase, compared to 53.2% in the chamber. The corresponding erythromycin MIC50 and MIC90 were 1.0 and 8.0 micrograms/ml with Oxyrase, compared to 4.0 and > 32.0 micrograms/ml by the reference method, with 89.3% of strains susceptible at a breakpoint of 4 micrograms/ml with Oxyrase, compared to 60.6% in CO2. Exclusion of CO2 from the anaerobic atmosphere when testing for susceptibility to azalides and macrolides yielded lower MICs, which may lead to a reconsideration of the role played by these compounds in treatment of infections caused by these strains.

Anaerobiosis↗

Escalation of CTX-M-producing extensively drug-resistant Shigella spp. in Kolkata, India, following the COVID-19 pandemic.

Shigella spp. is recognized by the World Health Organization as a high-priority pathogen due to its global prevalence, unique pathogenic mechanisms, and growing antimicrobial resistance (AMR). Nearly half of all Shigella strains worldwide are now multidrug-resistant (MDR), and the emergence of extensively drug-resistant (XDR) variants-resistant to ciprofloxacin, ceftriaxone, and azithromycin-has severely limited effective treatment options. The present study is based on prospective laboratory surveillance involving 323 Shigella isolates collected during 2021-2023, with pre-COVID-19 pandemic data included from a previously published study solely for historical comparison. The presence of antibiotic resistance genes (ARGs) was investigated, and whole-genome sequencing (WGS) was performed on representative isolates to assess phylogenetic relatedness with global isolates. Approximately 10% of isolates exhibited resistance to third-generation cephalosporins. While only 3% of Shigella isolates carried the blaCTX-M-15 gene from 2013 to 2019, its prevalence increased to 26% by 2022-2023. Among 38 ceftriaxone-resistant S. sonnei isolates, 33 were also resistant to azithromycin, categorizing them as XDR. These isolates showed 48% clonal similarity and high phylogenetic resemblance to the isolates reported from England. Hybrid genome assembly revealed a plasmid harboring both the blaCTX-M-15 and mphA ARGs. Conjugation experiments and plasmid profiling confirmed the plasmid's transferability. We report a rising trend in third-generation cephalosporin resistance among Shigella spp., primarily driven by the spread of extended-spectrum β-lactamase-producing S. flexneri and the emergence of XDR S. sonnei. These findings underscore the urgent need for strengthened national AMR containment strategies and enhanced international surveillance of cephalosporin-resistant Shigella to mitigate this growing public health threat.IMPORTANCEShigella is a leading cause of diarrheal disease globally and has been prioritized by the World Health Organization due to its rapid acquisition of antimicrobial resistance. Our prospective surveillance in Kolkata, India, reveals a worrisome escalation of third-generation cephalosporin resistance over the past decade, primarily associated with the spread of blaCTX-M-15 and the emergence of extensively drug-resistant (XDR) S. sonnei. The detection of plasmids carrying both blaCTX-M-15 and mphA, coupled with evidence of their transferability, highlights the potential for accelerated dissemination of multidrug resistance. When compared with a global data set of international genomes, the Kolkata XDR isolates were found to cluster closely with isolates reported from England. By linking local surveillance with global genomic context, our findings provide critical insights for treatment guidelines, antimicrobial stewardship, and the design of international containment strategies aimed at curbing the rise of cephalosporin- and azithromycin-resistant Shigella.

India↗

Follicular conjunctivitis caused by Chlamydia trachomatis in an infant Saharan population: molecular and clinical diagnosis.

AIMS: To ascertain the prevalence of acute trachoma as a supposed endemic disease among infants in the Saharan refugee camps of Tindouf (Algeria) and to evaluate the efficacy of treatment with a single dose of azithromycin. METHODS: 527 children aged between 3 and 17 were evaluated in the camp schools in October 2001. All the children were clinically and microbiologically examined, including slit lamp checks of anterior segment and two conjunctival swabs, one for the detection of membrane lipopolysaccharide by quick immunoassay test Clearview Chlamydia MF and the other for the detection of specific DNA by chlamydia plasmid specific polymerase chain reaction (PCR) assay. After examination, a single dose of azithromycin was administered to each child. One month later samples from positive children and 12 random negative children by the first PCR were taken to perform a new PCR assay. RESULTS: Chlamydia trachomatis was suspected in 2.47% of the children, papillary hypertrophy being the most frequently seen clinical sign. Scarring changes secondary to trachoma were detected in 11.7% of the children. Only four cases (0.8%) were positive to the immunoassay test and 12 cases (2.27%) were positive by PCR. After treatment a second PCR was performed on positive children and they were negative of chlamydia DNA amplification. However, one child who was negative and received the treatment was positive in the second PCR assay. CONCLUSION: Acute trachoma prevalence is much lower than expected among infants in this Saharan population. The possible reasons could be the recent improvements in hygiene and health care. Cicatricial trachoma is more frequent. The Clearview immunoassay test has very low sensitivity in the detection of this disease. A single dose of azithromycin is sufficient to treat chlamydial conjunctivitis. However, a programme of improvement in hygiene and health care is necessary to prevent re-infection.

Acute Disease↗

Tetracycline treatment does not eradicate Mycoplasma genitalium.

OBJECTIVES: To study the treatment efficacy of tetracyclines and azithromycin in Mycoplasma genitalium positive patients attending an STD clinic. METHODS: All M genitalium positive patients (34 men and 26 women) attending an STD clinic during a 6 month period were treated with antibiotics. All patients known to be partners of M genitalium positive patients and those who were M genitalium positive, but not initially treated, were treated with azithromycin. Patients with urethritis and/or cervicitis were treated with tetracyclines before their M genitalium status was known. RESULTS: 10 of 14 women (71%) and 10 of 16 men (63%) treated with tetracyclines were M genitalium positive at follow up, whereas all patients treated with azithromycin (16 men and 20 women) were M genitalium negative, at the 4 week follow up visit. CONCLUSIONS: These results suggest that tetracyclines are not sufficient to eradicate M genitalium. Randomised controlled treatment trials are urgently needed.

Anti-Bacterial Agents↗

Chlamydia pneumoniae infection in circulating human monocytes is refractory to antibiotic treatment.

BACKGROUND: Recovery of the intracellular bacterium Chlamydia pneumoniae from atherosclerotic plaques has initiated large studies on antimicrobial therapy in coronary artery disease. The basic concept that antibiotic therapy may eliminate and prevent vascular infection was evaluated in vitro and in vivo by examining the antibiotic susceptibility of C pneumoniae in circulating human monocytes, which are thought to transport chlamydiae from the respiratory tract to the vascular wall. METHODS AND RESULTS: Blood monocytes (CD14+) from 2 healthy volunteers were obtained before and after oral treatment with azithromycin or rifampin and then inoculated with a vascular C pneumoniae strain and continuously cultured in the presence of the respective antibiotic. Progress of infection and chlamydial viability was assessed by immunogold-labeling and detection of C pneumoniae-specific mRNA transcripts. Circulating monocytes from patients undergoing treatment with experimental azithromycin for coronary artery disease were examined for C pneumoniae infection by cell culture. Antibiotics did not inhibit chlamydial growth within monocytes. Electron microscopy showed development of chlamydial inclusion bodies. Reverse transcription-polymerase chain reaction demonstrated continuous synthesis of chlamydial mRNA for 10 days without lysis of the monocytes. The in vivo presence of viable pathogen not eliminated by azithromycin was shown by cultural recovery of C pneumoniae from the circulating monocytes of 2 patients with coronary artery disease. CONCLUSIONS: C pneumoniae uses monocytes as a transport system for systemic dissemination and enters a persistent state not covered by an otherwise effective antichlamydial treatment. Prevention of vascular infection by antichlamydial treatment may be problematic: circulating monocytes carrying a pathogen with reduced antimicrobial susceptibility might initiate reinfection or promote atherosclerosis by the release of proinflammatory mediators.

Aged↗

Antibiotic dosage in trachoma control programs: height as a surrogate for weight in children.

PURPOSE: National programs for trachoma control are implementing mass treatment programs in which azithromycin is used as part of the control strategy. Dose is determined by weight, which can be difficult to determine in field conditions. The purposes of this study were to determine whether an accurate dose could be determined by using height as a surrogate for weight and whether a single model of height-based dosage would be applicable in more than one setting. METHODS: Data on height, weight, age, and gender of 5558 children aged 6 months to15 years were obtained from Kongwa and Rombo, Tanzania; Malakal, Sudan; Jareng, The Gambia; and Daboya, Ghana. Models for predicting weight by measuring height were developed that incorporated country-specific parameters. Doses of azithromycin assumed suspension of 40 mg/mL and 250-mg tablets that could be halved. Tolerance limits were defined as 15 to 30 mg/kg. RESULTS: A regression model, predicting log weight as a function of log height, was the best fit and explained 94% of the variance. In children less than 1 year of age or 60 cm in height, dose determined by weight was preferred. Dosage by height resulted in more than 97% of children receiving doses within the tolerance limits. Children aged 1 to 2 years were the group most likely to be over- or undermedicated, but this occurred in only 6% of this age group. CONCLUSIONS: Height-based determination of dosage of azithromycin in trachoma control programs appears to be feasible, using the height-based schedule proposed. One model was adequate for all the countries in the study. Further expansion to other countries is warranted.

Adolescent↗

New macrolide antibiotics: usefulness in infections caused by mycobacteria other than Mycobacterium tuberculosis.

OBJECTIVE: To compare the pharmacology, in vitro activity, and clinical use of the new macrolide antibiotics, azithromycin and clarithromycin, in the treatment of infections caused by mycobacteria other than Mycobacterium tuberculosis. DATA IDENTIFICATION: An English-language literature search using MEDLINE (1987-1994), Index Medicus (1987-1994), Program and abstracts of the 31st (1991) and 32nd (1992) Interscience Conference on Antimicrobial Agents and Chemotherapy, and bibliographic reviews of related textbooks, review articles, and professional society publications. STUDY SELECTION: 105 articles were selected. In vitro and in vivo reports on the pharmacokinetics, microbiology, pharmacology, and effectiveness of clarithromycin and azithromycin were assessed to compare their effectiveness and safety. Emphasis was placed on the use of these new drugs in treating infections caused by Mycobacterium avium complex, Mycobacterium chelonae, and Mycobacterium fortuitum infections. RESULTS: A review of the in vitro activity of the new macrolides revealed moderate to very good activity against many strains of mycobacteria other than M. tuberculosis. Early clinical trials show promising results in pulmonary infections, lymphadenitis, cutaneous infections, and disseminated infections. CONCLUSIONS: The new macrolides, azithromycin and clarithromycin, show great promise for treating infections caused by these acid-fast bacteria. Clarithromycin is recommended as a component of combination therapy for the treatment of M. avium complex infections in patients with AIDS. The development of resistance in patients, particularly when these agents are used alone, has been reported.

Anti-Bacterial Agents↗

Rapid drug susceptibility of Mycobacterium avium complex using a fluorescence quenching method.

Mycobacteria Growth Indicator Tube (MGIT) is a recently introduced rapid growth detection method which uses an oxygen quenched fluorescent indicator. The present study evaluated the ability of this new method to determine the drug susceptibility of Mycobacterium avium complex (MAC). Thirty strains recovered from patients with AIDS were tested for susceptibility to clarithromycin, rifabutin, ciprofloxacin, azithromycin and amikacin using MGIT. Results were compared to susceptibilities determined by the agar dilution method. The results obtained showed a 100% correlation between MGIT and the agar dilution method for rifabutin and clarithromycin. There was a 100% correlation between the two methods for azithromycin against 27 strains. MGIT was well correlated with the agar dilution method for detecting resistance to clarithromycin, rifabutin and azithromycin in 4 days, but the correlation was poor when susceptibilities to ciprofloxacin and amikacin were determined. This rapid method is non-radiometric, noninvasive and does not require any special instruments.

Acquired Immunodeficiency Syndrome↗

Interaction of macrolides and ketolides with the phagocytic cell line PLB-985.

Interactions between antibacterial agents and polymorphonuclear neutrophils (PMNs) are a major focus of investigation. Owing to the variable drug susceptibility of PMNs from different individuals, in vitro studies require samples from large panels of healthy volunteers to reach statistical significance. Here, we used a phagocytic cell line, PLB-985, which can differentiate into mature PMNs in vitro, for the study of cellular interactions (drug uptake and antioxidant effects) of two macrolides (azithromycin and roxithromycin) and four ketolides [HMR 3004, HMR 3647 (telithromycin), HMR 3562 and HMR 3787]. The oxidative burst of differentiated (D) cells was inhibited by macrolides and ketolides. IC50% values (concentrations impairing the oxidative burst by 50%), determined after 30 min of incubation, were as follows for azithromycin, roxithromycin, HMR 3004, telithromycin, HMR 3562 and HMR 3787, respectively: 40, 39, 15, 23, 26, and 33 mg/l (fMLP stimulation) and 37, 86, 39, 43, 14, and 31 mg/l (PMA stimulation). These values were similar to those obtained with PMNs. Uptake of the two macrolides was significantly lower in non-differentiated (ND) cells than in D cells and PMNs. The cellular/extracellular (C/E) concentration ratios at 60 min for PMNs, D and ND PLB were respectively 67, 25 and 11 (roxithromycin) and 159, 137 and 48 (azithromycin). Ketolide uptake by ND-PLB was also significantly lower than that obtained with PMNs (C/E ratios at 60 min were about 75 versus 265 (HMR 3004), 36 vs 230 (telithromycin), 75 vs 235 (HMR 3562) and 20 vs 130 (HMR 3787). Although the active carrier system seemed to be present in ND cells, its activation pathway was not functional. Thus, the PLB-985 cell line is a good in vitro model for studying drug-PMN interactions. The use of ND and D cells may shed light on the nature and activation pathways of macrolide transport systems present on the PMN membrane.

Anti-Bacterial Agents↗

Which treatment for genital tract Chlamydia trachomatis infection?

A national opportunistic chlamydia screening programme, mainly targeting young sexually active women, is gradually being introduced across the UK and in future will predominantly occur in primary care sites. The relative efficacy of recommended antibiotic treatments for chlamydia has been poorly studied and especially that of single dose azithromycin. In Portsmouth, 1536 patients treated for chlamydia, with four different antibiotic regimens, during the Department of Health pilot study, were asked to return for test of cure. No difference in treatment outcome was found using doxycycline, oxytetracycline, erythromycin or azithromycin. Directly observed therapy with azithromycin may be especially helpful in treating young chlamydia-positive patients.

Adolescent↗

Treatment and prophylaxis of Mycobacterium avium complex.

The most common pathogens involved in disseminated bacterial infection in people with acquired immunodeficiency syndrome (AIDS) are organisms of the Mycobacterium avium-intracellulare complex (MAC). Azithromycin and clarithromycin, a new azalide and macrolide, respectively, are among the most potent monotherapies for MAC bacteraemia, Although many bloodstream isolates demonstrate increased minimum inhibitory concentrations after 4 months of treatment. Current recommended prophylaxis, based on the results of two randomized, double-blind, prospective studies, is rifabutin 300 mg daily for people with AIDS with < 100 CD4 lymphocytes/mm3. In the beige mouse model, we have shown that both azithromycin and clarithromycin prevent MAC bacteraemia following repetitive oral challenge. Clinical trails are now underway to confirm these effects in man; comparative treatments include placebo, rifabutin and an azalide/macrolide plus rifabutin. While combinations might be more effective and reduce the emergence of resistance, the spectre of cytochrome P-450 drug interactions necessitates careful study before combination prophylactic approaches are accepted. Such interactions are associated with rifabutin and some macrolides, although azithromycin may be less problematic in this respect as it appears to have little potential to interact with other antimicrobial agents.

AIDS-Related Opportunistic Infections↗

Atovaquone in the treatment of Babesia microti infections in hamsters.

The traditional therapy for the treatment of human Babesia microti infections has been the combination of clindamycin and quinine. However, in recent years, it has become apparent that some patients have not responded to this regimen. We became involved in the treatment of several cases of babesiosis in which atovaquone was used to treat this infection. Therefore, using the hamster model, we determined the efficacy of atovaquone alone as well as atovaquone plus azithromycin for the treatment of experimental babesiosis. Atovaquone (100 mg/kg/day) and atovaquone (100 mg/kg/day) with azithromycin (150 mg/kg/day) were effective agents for the treatment of experimental babesiosis in hamsters. When atovaquone was used as monotherapy recrudescences occurred. Organisms obtained from recrudescent animals, when inoculated into uninfected animals, proved to be unresponsive to atovaquone therapy, suggesting the emergence of drug resistance. Resistant organisms did not emerge in hamsters treated with the combination of atovaquone and azithromycin. Atovaquone should be considered in the therapeutic regimen of patients with babesiosis who have either failed standard therapy or have become intolerant to such therapy.

Animals↗

A cost-effectiveness analysis of screening and treatment for Chlamydia trachomatis infection in asymptomatic women.

OBJECTIVE: To assess the cost-effectiveness of identifying and treating asymptomatic female carriers of Chlamydia trachomatis. DESIGN: Cost-effectiveness analysis based on previously reported cohort analytic studies and average salaries and costs of medical care in Sweden. SETTING: Women attending youth, family planning, and gynecology clinics. PARTICIPANTS: 1000 women and their male sex partners. INTERVENTION: Screening with tissue cell culture, confirmed enzyme immunoassay, and DNA amplification assays based on either polymerase chain reaction or ligase chain reaction was compared with no screening (no treatment and no tracing of sexual contacts). The effect of antibiotic regimens on the outcome of the screening strategies was also evaluated. RESULTS: When the prevalence of chlamydial infection exceeded 6%, screening of women with DNA amplification assay and treatment of positive patients with a single oral dose of azithromycin given under supervision in the clinic was the most cost-effective intervention strategy. At greater prevalences, screening with enzyme immunoassay also generated savings and improved the cure rates compared with no screening, but such screening was less cost-effective than screening with a DNA amplification assay. Compared with no intervention, tissue cell culture is cost-effective only when the prevalence of infection is greater than 14%. Compared with the azithromycin regimen, the standard 7-day, twice-daily doxycycline regimen resulted in significantly lower cure rates because of patients' poor compliance with this regimen. CONCLUSION: For asymptomatic female carriers of C. trachomatis, screening with a DNA amplification assay combined with the single-dose azithromycin treatment of positive patients is the most cost-effective strategy when the prevalence is 6%. When the prevalence is lower than 6%, the decision to choose a competing strategy depends on the physician's view of the value of preventing an illness caused by untreated chlamydial infection.

Adolescent↗

The cost-effectiveness of prophylaxis for Mycobacterium avium complex in AIDS.

OBJECTIVE: To develop a simulation model to project costs, life expectancy, and cost-effectiveness in discounted dollars per quality-adjusted life-year (QALY) saved for clinical strategies to prevent Mycobacterium avium complex (MAC) in patients with AIDS. METHODS: We used natural history data from the Multicenter AIDS Cohort Study, efficacy and toxicity data from randomized clinical trials, and cost data from the AIDS Cost and Services Utilization Survey. The model permits timing of prophylaxis to be stratified by CD4 count (201-300, 101-200, 51-100, and < or = 50/mm3), and allows combinations of prophylaxis, crossover to second- and third-line agents for toxicity, and consideration of adherence, resistance, and quality of life. RESULTS: The model projects that the average HIV-infected patient with a beginning CD4 count between 201 and 300/mm3 has total lifetime costs of approximately $43,150 and a quality-adjusted life expectancy of 42.35 months. If azithromycin prophylaxis for M. avium complex is begun after the CD4 declines to 50/mm3, costs and quality-adjusted survival increase to approximately $44,040 and 42.78 months, respectively, for an incremental cost-effectiveness ratio of $25,000/QALY compared with no M. avium complex prophylaxis. Other prophylaxis options (i.e., rifabutin, clarithromycin, and combination therapies) either cost more but offer shorter survival, or have cost-effectiveness ratios above $260,000/QALY. Sensitivity analysis reveals that, for reasonable assumptions about quality of life, risk of infection, prophylaxis cost, adherence, and resistance, azithromycin remains the most cost-effective prophylaxis option. CONCLUSIONS: Azithromycin prophylaxis, begun after the CD4 count has declined to 50/mm3, is the most cost-effective M. avium complex prophylaxis strategy. Consistent with new United States Public Health Service guidelines, it should be the first-line prophylaxis option.

AIDS-Related Opportunistic Infections↗

[Susceptibility to macrolide antibiotics of Bordetella pertussis and Bordetella parapertussis strains isolated from whooping cough patients in 1968 and in 1997-99].

The activity of erythromycin, azithromycin, clarithromycin, dirithromycin, oleandomycin, roxithromycin, spiramycin and josamycin against 21 and 34 B. pertussis strains and against 6 and 8 B. parapertussis strains isolated respectively in the years 1968 and 1997-99 was examined. The antibiotic agar dilution method was used. The minimum concentration of macrolides which inhibited growth of B. pertussis and B. parapertussis was calculated for 50% (MIC50) and 90% (MIC90) of isolates. The susceptibility to macrolides of B. pertussis and B. parapertussis strains isolated in the years 1968 and 1997-99 did not differ significantly. The MIC90 values of erythromycin were the same for B. pertussis (MIC90 = 0.125 mg/l) and B. parapertussis strains (MIC90 = 0.25 mg/l) recovered in 1968 as for those recovered in the years 1997-99. The most active antibiotic against all strains was azithromycin (MIC90 = 0.06 mg/l). The least active antibiotics were oleandomycin (MIC90 = 2-4 mg/l) and spiramycin (MIC90 = 8 mg/l). The study showed that erythromycin remains the antibiotic of choice for treatment of whooping cough and in case of emergence of B. pertussis and/or B. parapertussis strains erythromycin resistant, can be replaced by azithromycin.

Anti-Bacterial Agents↗

[Eradication of Helicobacter pylori in patients with duodenal ulcer following the short course of treatment with azitromycin and amoxycillin].

The efficacy of short-term treatment with azithromycin in 17 patients with acute doudenal ulcer associated with H. pylori was evaluated. Bioptats of the gastric mucosa taken at the beginning and after one month of treatment were investigated for H. pylori presence by histological, bacteriological methods, by urease test and by PCR. All the patients with positive H. pylori test were treated with Gastrozol (omeperazole, ICN Pharmaceutical) 40 mg per day for 1 week followed by 20 mg per day for 3 weeks, Sumamed (azithromycin, peira) 0.5 g once daily for 3 days and amoxycillin 0.5 mg four times a day for 10 days. Bioptats analysis before treatment revealed H. pylori in 100% for PCR methods, in 94.1% for urease test, in 88.2% for histological test. After the treatment H. pylori was revealed in 12.5% for urease and histological test, in 18.8% for bacteriological test and in 25% for PCR test. Thus the treatment efficacy was 75%. Side effects for short-term azithromycin therapy were shown in 5.9% cases.

Adult↗

[Macrolides in the treatment of children with Mediterranean spotted fever].

Till now there is not a gold standard therapy for Mediterranean spotted fever (MSF) in children. Standard treatment for MSF is the administration of tetracycline or chloramphenicol, however both these drugs can cause significant adverse effects in children (tetracyclines can cause staining of teeth, chloramphenicol severe hematological adverse events such as aplastic anemia, gray baby syndrome and hemolytic anemia in patients with the Mediterranean form of G6PD deficiency). We conducted two randomized clinical trials; the first compared clarithromycin versus chloramphenicol: mean time to defervescence was 36.7 +/- 18.1 h in the clarithromycin group and 47.1+/- 21.9 h in the chloramphenicol group (P= 0.047). The second trial compared clarithromycin versus azithromycin and did not show any statistically significant difference: mean time to defervescence was 46.2 +/- 36.4 h in the clarithromycin group and 39.3 +/- 31.3 h in the azithromycin group (P= 0.34). On the basis of these studies we think that clarithromycin and azithromycin could constitute an acceptable alternative to chloramphenicol and to tetracyclines for the treatment of MSF in children

Adolescent↗

[Macrolide antibiotic resistance rates and phenotypes of group A beta hemolytic streptococci isolated between the years 1999-2000 and 2001-2002].

Macrolide resistance in group A beta hemolytic streptococci (GABHS) have been reported with increasing frequency from various geographic regions in the world, and for the respective treatment alternatives and epidemiologic studies, macrolide resistance rates and phenotypes have been determined. In this study erythromycin, clarithromycin and azithromycin were tested with disc diffusion method against 560 GABHS, isolated from the throat samples collected between 1999-2002. NCCLS guidelines were followed for the susceptibility tests and MIC values were obtained by E-Test in resistant isolates. For determining the resistance phenotype, erythromycin and clindamycin discs were used. Only one isolate (0.27%) was found intermediately resistant to erythromycin, and clarithromycin, and resistant to azithromycin between May 1999-January 2000, whereas in the period between January 2001-June 2002, one isolate (%0.5) was found susceptible to erythromycin and clarithromycin, but intermediately resistant to azithromycin. In each period three isolates (0.83% and 1.5%, respectively) were found to be resistant to all the tested macrolides. There was no statistically significant difference between the resistance rates in these periods. Three of the resistant isolates had inducible type, and the other five isolates had M phenotype macrolide resistance. Testing for macrolide susceptibilities and screening the resistance phenotypes have crucial importance in case of GABHS infections, since these can be taken into consideration for epidemiological issues as well as a guide for empirical treatment protocols in any geographical setting, as well as in our country.

Anti-Bacterial Agents↗