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PubMed2002

Solitary erythema migrans in children: comparison of treatment with azithromycin and phenoxymethylpenicillin.

OBJECTIVE: To compare clinical effectiveness and side effects of treatment with azithromycin or phenoxymethylpenicillin in children with solitary erythema migrans. METHODS: Consecutive patients younger than 15 years, referred to our institution in 1998 and 1999 with previously untreated typical solitary erythema migrans, were included in this prospective study. Basic demographic features and clinical data were collected by means of a questionnaire. The efficiency of treatment of acute disease, development of later major and/or minor manifestations of Lyme borreliosis and side effects of treatment were surveyed by follow-up visits during the first year. RESULTS: Forty-two patients received azithromycin 20 mg/kg/day for the first day followed by 10 mg/kg/day for a further four days and phenoxymethylpenicillin 100,000 IU/kg/day for 14 days. No differences in demographic and clinical pre-treatment characteristics were present in the two groups, with the exception of the duration of erythema migrans before treatment (3 days in the azithromycin group versus 4 days in the phenoxymethylpenicillin group; p = 0.0320). The clinical course during the post-treatment period revealed no significant differences between the two groups in the duration of EM (3 days versus 4 days; p = 0.2471), the appearance of minor manifestations of Lyme borreliosis (17.5% in the azithromycin group versus 24.4% in the phenoxymethyl-penicillin group; p = 0.6252), or in the emergence of major manifestations of Lyme borreliosis (one patient in each treatment group). One year after antibiotic treatment all patients were asymptomatic. Side effects of treatment were observed in 5.3% of patients treated with azithromycin and in 6% treated with phenoxymethylpenicillin. The appearance of "Herxheimer's reaction" at the beginning of treatment was recorded in 7 out of 42 patients (6%) in each treatment group. CONCLUSIONS: Azithromycin and phenoxymethylpenicillin are equally effective in treatment of children with solitary erythema migrans and have comparable side effects.

Adolescent↗
PubMed2003

[Comparative analysis of the effectiveness and costs of azithromycin and cefoperazone treatment of patients during COPD exacerbation].

UNLABELLED: The effectiveness and costs of azithromycin and cefoperazone treatment of COPD exacerbation have been analysed in this study. Forty patients at the mean age of 65.9 (+/- 11.5) years were enrolled. The subjects were randomly selected and treated either with cefoperazone 2 x 1.0 g i.v. daily (group I = 20 persons) or with azithromycin 1 x 0.5 g (group II = 20 persons), in sequential method. Body temperature, cough intensity, quality and quantity of expectorated sputum, number of breaths per minute and adverse events were recorded daily. The values of pulmonary function tests and leucocytosis were assessed three times during the study. Statistically significant differences between both groups have been found with respect to the mean time of staying in hospital (9.1 days--group I vs 6.1 days--group II), mean total duration of antibiotic therapy (10.1 days--group I vs. 6.6 days--group II) and duration of intravenous antibiotic therapy only [7.5 days (group I) vs 2.9 days (group II)] (p < 0.05). Taking into account the duration of hospitalization, it was shown that the mean total costs of treatment of COPD exacerbation with azithromycin was significantly lower than that of treatment with cefoperazone (2375.9 PLN and 1663.7 PLN, respectively) (p < 0.05). CONCLUSIONS: The effectiveness of treatment with azithromycin in patients with COPD exacerbation was evident. The total costs of treatment of COPD exacerbation with azithromycin is lower than with cefoperazone. Both azithromycin and cefoperazone are safe in the treatment of exacerbation of COPD.

Acute Disease↗
PubMed2003

Household willingness to pay for azithromycin treatment for trachoma control in the United Republic of Tanzania.

OBJECTIVE: Household willingness to pay for treatment provides important information for programme planning. We tested for relationships between socioeconomic status, risk of trachoma, perceptions of the effects of azithromycin, and the household willingness to pay for future mass treatment with azithromycin. METHODS: We surveyed 394 households in 6 villages located in central United Republic of Tanzania regarding their willingness to pay for future azithromycin treatment. A random sample of households with children under 8 years of age was selected and interviewed following an initial treatment programme in each village. Data were gathered on risk factors for trachoma, socioeconomic status, and the perceived effect of the initial azithromycin treatment. Ordered probit regression analysis was used to test for statistically significant relationships. FINDINGS: 38% of responding households stated that they would not be willing to pay anything for future azithromycin treatment, although they would be willing to participate in the treatment. A proxy for cash availability was positively associated with household willingness to pay for future antibiotic treatment. Cattle ownership (a risk factor) and being a household headed by a female not in a polygamous marriage (lower socioeconomic status) were associated with a lower willingness to pay for future treatment. A perceived benefit from the initial treatment was marginally associated with a willingness to pay a higher amount. CONCLUSIONS: As those at greatest risk of active trachoma indicated the lowest willingness to pay, imposing a cost recovery fee for azithromycin treatment would likely reduce coverage and could prevent control of the disease at the community level.

Adult↗
PubMed2005

Randomized, controlled, double-blind trial of daily oral azithromycin in adults for the prophylaxis of Plasmodium vivax malaria in Western Thailand.

We assessed the prophylactic efficacy of azithromycin (250 mg/day) against malaria in 276 adults in western Thailand in a randomized, double-blind, placebo-controlled trial. After antimalarial suppressive treatment, volunteers were randomized in a 2:1 ratio to either the azithromycin or placebo, respectively. Study medication was given for an average of 74 days. The azithromycin group (n = 179) had five endpoint parasitemias (1 Plasmodium vivax and 4 P. falciparum), and the placebo group (n = 97) had 28 endpoint parasitemias (21 P. vivax, 5 P. falciparum, and 2 mixed infections). Adverse events and compliance and withdrawal rates were similar in both groups. The protective efficacy (PE) of azithromycin was 98% for P. vivax (95% confidence interval [CI] = 88-100%). There were too few cases to reliably estimate the efficacy of azithromycin for P. falciparum (PE =71%, 95% C =-14-94%). We conclude that daily azithromycin was safe, well-tolerated, and had a high efficacy for the prevention of P. vivax malaria.

Adult↗
PubMed2006

Treatment of cyclosporine-induced gingival overgrowth with azithromycin-containing toothpaste.

OBJECTIVES: Gingival overgrowth is a complication of cyclosporine therapy following organ transplantation. Oral azithromycin is frequently used to treat this complication. This study examined the efficacy of local azithromycin, in the form of toothpaste, against cyclosporine-induced gingival overgrowth. MATERIALS AND METHODS: Twenty stable renal transplanted patients (10 men and 10 women) with gingival hyperplasia were randomly assigned to a test group and a control group. Azithromycincontaining toothpaste had 85 mg azithromycin per gram of toothpaste. Both toothpastes were prescribed b.i.d., each time using 1.5 cm, for 1 month. All participants received scaling, root planing, polishing, and oral hygiene instructions, at least 4 weeks prior to initiation of the study. Gingival overgrowth index, bleeding on probing, blood urea nitrogen, creatinine, and serum cyclosporine levels were measured at baseline, and then again in the second and fourth weeks after tooth brushing. Patient satisfaction with the toothpastes was evaluated by a visual analogue scale. The stability of clinical responses was followed for 3 months after cessation of the toothpastes. RESULTS: Gingival overgrowth index decreased significantly in the azithromycin-containing toothpaste group (from 1.1+/-0.56 to 0.51+/-0.47, P<.001); however, in the control group, this decrease was not significant (P=.22). Bleeding on probing also decreased significantly in patients in the azithromycin-containing toothpaste group compared with controls (P=.001). When compared with baseline levels, trough levels of cyclosporine, blood urea nitrogen, and creatinine did not change in either of the groups. Patients in the control group were more satisfied with the toothpaste than were patients in the test group (53 vs 38). CONCLUSIONS: Azithromycin-containing toothpaste is an effective, simple, and noninvasive treatment for cyclosporine-induced gingival overgrowth.

Adult↗
PubMed1990

Mechanism of azithromycin uptake in human polymorphonuclear leucocytes.

The new antibiotic azithromycin (CP-62.993) is enriched in human polymorphonuclear leucocytes by up to 300-fold the extra-cellular concentrations. To approach an understanding of the underlying mechanism of this unique behavior of azithromycin, some characteristics of the uptake process were investigated in vitro. The speed of the uptake in human polymorphonuclear leucocytes was found to be independent of the extracellular starting concentrations of azithromycin. There was no indication of saturation up to extracellular concentrations of 100 micrograms/ml. The uptake was largely determined by incubation temperatures. At 4 degrees C no penetration into the cells could be observed. The activation energy of azithromycin uptake came to 144 kJ mol-1, twice the value of erythromycin uptake. The presence of various inhibitors of cell metabolism did not change the intracellular accumulation compared to control, nor did the presence of some agents which interfere with certain transport channels. These findings suggest that passive diffusion is an essential mechanism of azithromycin transport through the phagocyte membrane, while active transport is less important. The high cellular enrichment of azithromycin and the relatively high activation energy of the uptake process could be explained by accumulation of the drug in phagocytic lysosomes and this would also be in keeping with pH partition considerations.

Adult↗
PubMed1995

Azithromycin does not increase plasma concentrations of oral midazolam.

Interaction between azithromycin and midazolam was investigated in a double-blind, randomized crossover study of 2 phases. Ten healthy volunteers were given azithromycin (500 mg on day 1 and 250 mg on days 2-5) or placebo pretreatments. On day 5 they ingested 15 mg midazolam. Plasma samples were collected and psychomotor performance measured for 17 h. Azithromycin treatment increased the median (range) concentration peak time of midazolam from 1.0 (0.5-2) h to 1.25 (0.5-5) h and decreased plasma concentrations of midazolam during initial 3 hours after the intake of midazolam (p < 0.05). Mean +/- SE mean peak concentration of midazolam was decreased from 86 +/- 17 ng ml-1 to 57 +/- 9 ng ml-1 (p < 0.05). Azithromycin did neither increase the total area under concentration-time curve nor change the elimination half-life of midazolam. In Maddox wing test the maximum effects of midazolam were reached later during azithromycin phase, but no other changes were observed in pharmacodynamics of midazolam. Azithromycin may delay the absorption of midazolam, which can postpone the onset of action of midazolam.

Administration, Oral↗
PubMed1994

Azithromycin and erythromycin in the treatment of cervical chlamydial infection during pregnancy.

OBJECTIVE: To compare azithromycin and erythromycin in regard to side effects, intolerance, and cure rate in a pregnant population with chlamydial cervicitis. METHODS: Thirty women were randomized to receive either erythromycin, 500 mg orally four times a day for 7 days, or azithromycin, 1 g orally as one dose. All subjects completed questionnaires identifying the incidence of nausea, vomiting, diarrhea, abdominal pain, and anorexia. Post-treatment cultures were taken from all subjects. RESULTS: All subjects receiving erythromycin reported two or more gastrointestinal side effects, versus none in the azithromycin group (P < .001). Five of 15 subjects in the erythromycin treatment arm were intolerant to the 500-mg dose given four times a day, compared to none in the azithromycin group (P < .025), so the dosage was lowered to 250 mg four times a day to complete the course. Repeat cervical testing demonstrated similar cure rates for both medications: 100 and 93% (14 of 15) for azithromycin and erythromycin, respectively. CONCLUSION: These data suggest that azithromycin is a valid treatment option in pregnant patients who cannot tolerate erythromycin because of side effects.

Administration, Oral↗
PubMed1995

[Azithromycin and bronchopulmonary infections].

Azithromycin is a molecule of the macrolide family, belonging to the azalides class. Several of its characteristics allow for its use in the treatment of the community-acquired lower respiratory tract infections. Commonly isolated pathogens in bronchial infections are most frequently H. influenzae, S. pneumoniae, M. catarrhalis, C. pneumoniae and M. pneumoniae, and more rarely or in the context of a particular background, S. aureus, Gram negative bacteria and L. pneumophila. MIC90 of these germs is generally low or slightly elevated, displaying an inhibitory activity of the azithromycin on these bacteria. Nevertheless, the frequency of macrolide-resistant S. pneumoniae is not negligible and this germ must be considered as inconstantly susceptible to the macrolide family. Pharmacokinetics studies evidenced from high to very high azithromycin concentrations in the pulmonary tissues, reaching values well above MIC of pathogens commonly isolated. Given the long half-life, these concentrations persist a long time after oral administration. As azithromycin concentrates much in polymorphonuclear leucocytes, they release azithromycin after having migrated into the infectious site by chimiotactism, thus allowing to increase the antibiotic concentration at infection site. These requirements have been confirmed in vivo in animal models and in clinical studies. Two experimental models on macrolide susceptible S. pneumoniae, and H. influenzae evidenced a better activity of azithromycin in comparison to other macrolides tested against these two germs.

Acute Disease↗
PubMed1996

Azithromycin in the treatment of pneumonias caused by Chlamydia spp: a retrospective study.

A retrospective study was undertaken in order to compare the efficacy and safety of azithromycin and doxycycline in the treatment of pneumonias caused by Chlamydia spp. Patients with radiologically confirmed pneumonia and positive complement fixation test for chlamydial infection who were hospitalized in the University Hospital of Infectious Diseases, Zagreb during the years 1989-1992 were reviewed. Among them, 83 were treated with azithromycin, given in a total dose of 1.5 g over 5 days (500 mg once daily at day 1 followed by 250 mg at days 2-5, 60 patients) or 3 days (500 mg once daily, 23 patients). Twenty-two patients were treated with doxycycline (100 mg b.i.d. for 10 days). Treatment groups were comparable with respect to age, sex, and severity of signs and symptoms of illness. All the patients were cured. There were no differences in duration of fever after treatment initiation between patients treated with azithromycin (whether pretreated with beta-lactam antibiotics or not) and doxycycline (p > 0.05). In addition, 3- and 5-day azithromycin courses were equally effective (p > 0.05). Both drugs were well tolerated, and only two patients treated with azithromycin reported nausea. It may be concluded that in the treatment of pneumonias caused by Chlamydia spp. azithromycin is as effective and well tolerated as doxycycline.

Adolescent↗
PubMed2006

Pregnancy outcome following gestational exposure to azithromycin.

BACKGROUND: Azithromycin is an azalide antibiotic with an extensive range of indications and has become a common treatment option due to its convenient dosing regimen and therapeutic advantages. Human studies addressing gestational use of azithromycin have primarily focused on antibiotic efficacy rather than fetal safety. Our primary objective was to evaluate the possibility of teratogenic risk following gestational exposure to azithromycin. METHODS: There were 3 groups of pregnant women enrolled in our study: 1) women who took azithromycin, 2) women exposed to non-teratogenic antibiotics for similar indications, and 3) women exposed to non-teratogenic agents. They were matched for gestational age at time of call, maternal age, cigarette and alcohol consumption. Rates of major malformations and other endpoints of interest were compared among the three groups. RESULTS: Pregnancy outcome of 123 women in each group was ascertained. There were no statistically significant differences among the three groups in the rates of major malformations; 3.4% (exposed) versus 2.3% (disease matched) and 3.4% (non teratogen) or any other endpoints that were examined. In the azithromycin group, 88 (71.6%) women took the drug during the first trimester CONCLUSION: Results suggest that gestational exposure to azithromycin is not associated with an increase in the rate of major malformations above the baseline of 1-3%. Our data adds to previous research showing that macrolide antibiotics, as a group, are generally safe in pregnancy and provides an evidence-based option for health professionals caring for populations with chlamydia.

Journal Article↗
PubMed2026

A Randomized Clinical Trial to Compare Moxifloxacin Versus Azithromycin for the Treatment of Mycoplasma genitalium: The FARTHEST Study.

BACKGROUND: Mycoplasma genitalium (MG) is increasingly characterized by high rates of macrolide and fluoroquinolone resistance. International guidelines recommend resistance-guided therapy; however, access to genotypic testing is limited, and randomized trial evidence is lacking. We assessed the efficacy of moxifloxacin and azithromycin without resistance assays. METHODS: This monocentric, open-label, superiority, randomized controlled trial enrolled adults with MG infection detected by multiplex PCR, randomized 1:1 to receive moxifloxacin 400 mg daily for 10 days or azithromycin 500 mg daily for 6 days. A test of cure was performed &#x2265;28 days after treatment completion. The primary endpoint was microbiological cure in the intention-to-treat (ITT) and per-protocol (PP) populations. Subgroup analyses assessed symptomatic versus asymptomatic infections, doxycycline exposure, re-treatment, and sexual behavior. RESULTS: Among 358 randomized participants, 87.0% of those treated with moxifloxacin and 61.2% of those treated with azithromycin achieved microbiological cure in the ITT analysis (absolute risk difference 25.8%, 95% CI 16.5, 35.2). The superiority of moxifloxacin was confirmed in the ITT and PP populations. Moxifloxacin remained superior across most subgroups, whereas azithromycin showed comparable efficacy only among heterosexual individuals. Doxycycline coadministration did not improve outcomes. Both regimens were well tolerated, with only one case of discontinuation. CONCLUSIONS: Moxifloxacin demonstrated superior efficacy compared to azithromycin for treating MG infection in the absence of resistance testing. These randomized data support the use of moxifloxacin as a first-line option when resistance assays are unavailable and may inform treatment strategies.

Humans↗
PubMedDate not supplied

Efficacy of azithromycin in reducing lower genital Ureaplasma urealyticum colonization in women at risk for preterm delivery.

OBJECTIVE: The purpose of this study was to determine if azithromycin is effective in reducing lower genital colonization of Ureaplasma urealyticum in women with preterm labor or preterm premature rupture of membranes (PROM). METHODS: A randomized, double-blinded, placebo-controlled prospective study of 60 pregnancies was carried out between 22 and 34 weeks. Genital mycoplasma cultures were performed at the time of admission. Patients were randomized to receive either a single dose of azithromycin (four 250 mg capsules) or a placebo in addition to prophylactic intravenous ampicillin. Repeat cultures were done on undelivered patients 7 days after enrollment. The study had power to detect a 50% decrease in colonization. RESULTS: Overall, lower genital colonization was 47/59 (79.7%) for U. urealyticum. Seven days after enrollment, U. urealyticum was isolated in 14/15 (93.3%) of the azithromycin-treated cases and in 11/14 (78.6%) of the controls (RR = 1.19, 95% CI = 0.88-1.61). Vertical transmission of U. urealyticum was 3/15 (20%) in the azithromycin-treated cases and 5/10 (50%) for the controls (RR = 0.40, 95%, CI = 0.12-1.31). CONCLUSION: These data suggests that a single 1 g dose of azithromycin is ineffective in reducing lower genital colonization with U. urealyticum.

Adult↗
PubMed2005

Effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media in children: a population-based study.

UNLABELLED: Population-based studies may give results different from randomized clinical trials assessing the efficacy of antibiotics. OBJECTIVE: To determine the effectiveness of amoxicillin, azithromycin, cefprozil and clarithromycin in the treatment of acute otitis media (AOM) in children. METHODS: Using Quebec Health Insurance databases (RAMQ), we selected a cohort of children aged < or = 6 years, with a first episode of AOM between 1999 and 2002. The index AOM was defined as a medical service claim with a diagnosis of AOM and an antibiotic dispensation in the following 72 hours. Failures were defined as a new antibiotic dispensation, a hospitalization or outpatient visit for complications related to AOM in the 30 days after the index AOM. Data were analyzed using logistic regression. RESULTS: Overall, 12,693 failures occurred among 60,513 first episodes of AOM. Azithromycin was the only antibiotic that was associated with a decreased risk of failure overall, when compared to amoxicillin (OR 0.88, 95% CI: 0.82, 0.94). However in the first 3 days of treatment (n = 680), azithromycin was more associated with treatment failure (OR 1.6, 95% CI: 1.3, 2.0). Compared to amoxicillin, post-therapy failures (n = 9387) were more likely to occur with cefprozil (OR 1.2, 95%CI: 1.2, 1.3) but were less with azithromycin (OR 0.8 95% CI: 0.8, 0.9). CONCLUSIONS: Azithromycin had the lowest risk of failure 30 days after the onset of treatment but an increased risk of failure during the first few days of treatment. Amoxicillin remains an effective first-line drug for treating first AOM episodes.

Acute Disease↗
PubMed2000

Azithromycin: antimalarial profile against blood- and sporozoite-induced infections in mice and monkeys.

The spectrum of antimalarial activity of the new macrolide antibiotic azithromycin was evaluated against blood- and sporozoite-induced infections with a chloroquine-resistant strain of Plasmodium yoelii nigeriensis (N-67) in Swiss mice and with simian parasite Plasmodium cynomolgi B in rhesus monkeys. Against experimental rodent malaria, a 70 mg/kg/day dose showed curative blood-schizontocidal activity in a four-dose regimen administered orally from day 0 to day 3 or from day 2 to day 5 to mice harboring established infection. The curative response was also obtained with a 40 mg/kg/day dose administered in an extended seven-dose (days 0-6) regimen. Azithromycin was also effective in the causal prophylactic test, since a 50 mg/kg dose from day -1 to day +2 protected mice against P. y. nigeriensis (N-67) sporozoite challenge. In comparison, erythromycin did not show either of the above activities up to a 405 mg/kg/day dose in identical regimens. Comparison of the ED(90) values showed that azithromycin was 31-fold more effective than erythromycin as a blood schizontocide. In the simian model, trophozoite-induced infections of P. cynomolgi B were cured with 25 mg/kg/day azithromycin administered for 7 days. In the causal prophylactic test, the prepatent period was significantly extended in monkeys challenged with P. cynomolgi B sporozoites, presumably because of the growth inhibition of preerythrocytic schizonts in hepatocytes. Azithromycin did not exhibit any hypnozoitocidal (dormant exoerythrocytic stages) activity at 25 mg/kg/day in a seven-dose regimen.

Animals↗
PubMed1999

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↗
PubMed1997

Synergistic effect of azithromycin on the phagocytic killing of Staphylococcus aureus by human polymorphonuclear leukocytes.

Many macrolides have been shown to affect the interaction between bacteria and various immune defense mechanisms, such as chemotaxis, accumulation, and bioactivity within phagocytic cells. The interaction of azithromycin with human polymorphonuclear leukocytes (PMNs) was studied in vitro and compared with the interactions between other macrolides and PMNs. The opsonophagocytic killing of Staphylococcus aureus was synergistically enhanced by azithromycin at concentrations below and above the minimal inhibitory concentration, with a reduction of up to 2.82 log10 cfu/ml with 2 mg/ml of azithromycin. Other macrolides were effective only at subinhibitory concentrations. The beneficial azithromycin-leukocyte interaction may explain azithromycin's efficacy against intracellular pathogens.

Anti-Bacterial Agents↗
PubMed1997

Potentiation of antifungal activity of amphotericin B by azithromycin against Aspergillus species.

The potential role of azithromycin in combination with amphotericin B against 25 clinical isolates of Aspergillus was assessed. The MIC of amphotericin B was 1 microg/ml for 44% of the isolates, 0.5 microg/ml for 48%, and 0.25 microg/ml for 8%. All isolates were resistant to azithromycin. Synergism, defined as a > or = twofold reduction in the MIC of both drugs upon combination, was demonstrated between amphotericin B and azithromycin for all 25 isolates. To prove that azithromycin exerts its antifungal effect by inhibiting protein synthesis, we studied [35S]-methionine incorporation into protein in one Aspergillus isolate. Neither amphotericin B at 0.125 microg/ml (fourfold below its MIC) nor azithromycin at 16 microg/ml (> or = 16-fold below its MIC) had any effect on protein synthesis when tested alone. Upon combination, however, a 68% inhibition in protein synthesis was evident by the inhibition of [35S]-methionine incorporation.

Amphotericin B↗