Hospital survey of antimicrobial prophylaxis to prevent endocarditis in patients with prosthetic heart valves.

The American Heart Association (AHA) has published guidelines for use of prophylactic antibiotics to prevent bacterial endocarditis, but few data are available about physician compliance with these guidelines. A retrospective review was conducted of the use of prophylactic antibiotics in patients with prosthetic heart valves who were undergoing diagnostic or operative procedures or heart catheterization at three hospitals. Compliance with AHA recommendations was only 30 percent (14 of 46) for procedures considered high risk for patients with prosthetic heart valves. Six (23 percent) of 26 patients who underwent right or left heart catheterization received prophylactic antibiotics (not recommended by AHA). Antibiotics were given to 42 (74 percent) of 57 patients who underwent surgical procedures considered at low risk of bacteremia, but only 33 (58 percent) received antibiotics that cover organisms commonly present at the site of the procedure. The results indicate that clinicians frequently do not administer prophylactic antibiotics in patients with prosthetic heart valves who are undergoing invasive procedures or do not follow published AHA guidelines when antibiotics are administered.

Presence of macrolide resistance in respiratory flora of HIV-Infected patients receiving either clarithromycin or azithromycin for Mycobacterium avium complex prophylaxis.

Clarithromycin 500 mg po bid or azithromycin 1200 mg po weekly is recommended as first line prophylaxis for Mycobacterium avium complex (MAC) in patients with HIV infection whose CD4 counts are <50 cells/microL. HIV-infected patients with CD4+ T-cell counts <200 cells/microL were randomized to receive either clarithromycin 500 mg po bid or azithromycin 1200 mg po weekly for 12 weeks. Nasopharyngeal swabs for Streptococcus pneumoniae and Haemophilus influenzae plus an anterior nare culture for Staphylococcus aureus were obtained at pretreatment, at 6 weeks, and at 12 weeks. A throat culture for oral flora was obtained for susceptibility testing against erythromycin. Minimum inhibitory concentrations (MICs) for clarithromycin and azithromycin were performed on all S. pneumoniae, H. influenzae, and S. aureus isolates. The study was terminated after respiratory flora, from all participants, revealed macrolide resistance. Because results of recent randomized trials indicate minimal efficacy of continuing MAC prophylaxis in patients who respond to potent combination antiretroviral therapy, the observed high incidence of macrolide-resistant bacterial colonization of the respiratory tract in this trial supports the discontinuation of macrolide prophylaxis in all AIDS patients whose CD4 counts have risen above 100 cells/microL.

Phase III, randomized, double-blind study of clarithromycin extended-release and immediate-release formulations in the treatment of patients with acute exacerbation of chronic bronchitis.

BACKGROUND: Clarithromycin has an established efficacy and safety profile in the treatment of respiratory tract infections. OBJECTIVE: The purpose of this study was to compare the clinical and bacteriologic efficacy and tolerability of clarithromycin extended-release and immediate-release formulations in patients with acute exacerbation of chronic bronchitis (AECB). METHODS: In a phase III, randomized, double-blind, parallel-group, multicenter study. patients aged > or =12 years with signs and symptoms of AECB and a productive cough with purulent sputum received treatment with extended-release (two 500-mg tablets once daily) or immediate-release (one 500-mg tablet twice daily) clarithromycin for 7 days. Assessments were performed before treatment, within 48 hours after treatment, and at the test-of-cure visit (study days 19-21). Patients who took > or =1 dose of study drug were included in the safety analysis. RESULTS: Of 620 patients randomized and treated, 182 were clinically and bacteriologically assessable (100 in the extended-release group and 82 in the immediate-release group). Treatment groups were well matched with respect to demographic characteristics and medical and social history. At the test-of-cure visit, 83% (83/100) of patients in the extended-release and 82% (67/82) of patients in the immediate-release group achieved clinical cure; 86% (85/99) and 85% (70/82), respectively, demonstrated bacteriologic cure. Overall pathogen eradication rates were 86% (100/116) in the extended-release group and 88% (86/98) in the immediate-release group. The most frequently reported adverse events were diarrhea (6% in extended-release group vs 4% in immediate-release group; no significant difference), taste alterations (4% in each group), and nausea (3% in each group); no clinically meaningful changes in laboratory values or vital signs, as assessed by the investigator, were observed. CONCLUSION: This study suggests that clarithromycin extended-release and immediate-release formulations have equivalent clinical and bacteriologic efficacy and tolerability in patients with AECB.

Phase III, randomized, double-blind study of clarithromycin extended-release and immediate-release formulations in the treatment of adult patients with acute maxillary sinusitis.

BACKGROUND: Clarithromycin has an established bacteriologic efficacy and safety profile in the treatment of respiratory tract infections. OBJECTIVE: This study compares the efficacy and tolerability of extended-release and immediate-release formulations of clarithromycin in patients with acute maxillary sinusitis. METHODS: Fourteen days' treatment with once-daily clarithromycin was compared with the immediate-release, twice-daily formulation in a phase III, randomized, double-blind, parallel-group, multicenter study. Patients aged > or =12 years with signs, symptoms, and a radiologically confirmed diagnosis of acute maxillary sinusitis were eligible. Patients were assessed before treatment, within 48 hours after treatment, on study days 16 to 18, and at the test-of-cure visit on study days 24 to 31. Patients who received > or =1 dose of study drug were included in the safety analysis. RESULTS: Of 283 patients treated, 245 were included in the efficacy analysis (122 in the extended-release group, 123 in the immediate-release group). Treatment groups were well matched with respect to demographic characteristics and medical condition and history. At the test-of-cure visit, 85% of patients in the clarithromycin extended-release group and 79% in the immediate-release group were deemed clinical cures; 89% and 91% in the extended-release and immediate-release groups, respectively, demonstrated radiographic success. Overall incidences of study drug-related adverse events were similar in the 2 treatment groups (32% in the extended-release group and 28% in the immediate-release group); however, significantly fewer patients receiving extended-release clarithromycin (2/142 11%]), compared with those receiving the immediate-release formulation (10/141 [7%]: P = 0.02) discontinued therapy because of drug-related gastrointestinal symptoms or abnormal taste. No clinically meaningful changes in laboratory values or vital signs were observed during the study. CONCLUSION: Although the efficacy of the 2 formulations was comparable, once-daily clarithromycin extended-release was better tolerated than the twice-daily immediate-release formulation by patients with acute maxillary sinusitis.

Thymostimuline and uterine cancer satellite lymph nodes. Morphometric comparison between an 8-day-before-surgery and a 14-day-before-surgery single treatment.

The Authors analyse the functional areas (cortical, paracortical, germinal center, medullary, histiocytosis of the sinuses) of regional lymph nodes in women having uterine carcinoma and previously treated with Thymostimuline, and who were operated on respectively 8 and 14 days after inoculation. They also evaluate the degree of significance when compared with a control group treated locally with a physiological solution. The number of lymph nodes examined is at least 5, and the stereological analysis was carried out with the use of a grid: 200 points, actual area 200 cm2, effective area at the level of the preparation 0.32 mm2 (250 X). The Authors examine the results obtained after 8 days' action by Thymostimuline, and, after 14 days, the difference between the 8-day-after and the 14-day-after administration results, and those between the cervical and the endometrial. 4 women with uterine cancer (Stages I and II) and treated with the same doses of physiological saline solution were used as controls.

Macrolide therapy of group A streptococcal pharyngitis: 10 days of macrolide therapy (clarithromycin) is more effective in streptococcal eradication than 5 days (azithromycin).

We compared recommended doses of 2 oral macrolide antibiotics (10 days of clarithromycin, 5 days of azithromycin) for eradicating group A streptococci from the throats of individuals aged > or = 12 years with symptomatic pharyngitis and a positive throat culture. Patients received either clarithromycin (250 mg b.i.d. for 10 days [n=260]) or azythromycin (500 mg on day 1, followed by 250 mg q.d. for 4 days [n=265]). Follow-up throat cultures were obtained both at 13--19 days and at 28--38 days. We evaluated 392 patients (median age, 26 years; clarithromycin, 194 patients; azyithromycin, 198 patients). Ten days of clarithromycin therapy was more effective than 5 days of azithromycin therapy in eradicating the organism (91% [176/194] vs. 82% [162/198]; P=.012). More than 97% of all streptococcal isolates were macrolide-sensitive. Whether these bacteriologic eradication rates were the result of the 2 macrolides compared or were due to differences in duration of therapy could not be determined, but the statistically significant difference in eradication of group A streptococci does raise additional questions about shortened courses of macrolide therapy for this common infection.

Clarithromycin resistance and susceptibility patterns of Mycobacterium avium strains isolated during prophylaxis for disseminated infection in patients with AIDS.

A randomized, placebo-controlled trial was conducted to evaluate the efficacy of clarithromycin in the prevention of disseminated Mycobacterium avium complex (MAC) infection in patients with AIDS; special attention was given to the development of clarithromycin resistance. The median time to documented MAC bacteremia was 199 days for placebo-treated patients, 217 days for clarithromycin-treated patients infected with clarithromycin-susceptible MAC, and 385 days for clarithromycin-treated patients infected with clarithromycin-resistant MAC. Most of the patients with clarithromycin-resistant isolates (91%) had a baseline CD4 T-cell count of < 20/microL, while these low counts occurred in only 25% of patients having clarithromycin-susceptible breakthrough isolates. The emergence of clarithromycin resistance did not affect the total period of survival. Resistance to clarithromycin in breakthrough MAC isolates emerges most likely when the patient is extremely immunodeficient at the time of initiation of the preventative therapy.

A randomized trial of clarithromycin as prophylaxis against disseminated Mycobacterium avium complex infection in patients with advanced acquired immunodeficiency syndrome.

BACKGROUND: Disseminated infection with Mycobacterium avium complex is the most common opportunistic infection in patients with advanced stages of the acquired immunodeficiency syndrome (AIDS). We studied the efficacy and safety of prophylactic treatment with clarithromycin, a macrolide antibiotic. METHODS: We conducted a randomized, placebo-controlled, double-blind study of clarithromycin in patients with AIDS in the United States and Europe. Entry criteria included blood cultures that were negative for M. avium complex, a Karnofsky performance score of 50 or higher, a CD4 cell count of 100 or less per cubic millimeter, and a life expectancy of at least six months. RESULTS: After the first interim analysis, the study was stopped. M. avium complex infection developed in 19 of the 333 patients (6 percent) assigned to clarithromycin and in 53 of the 334 (16 percent) assigned to placebo (adjusted hazard ratio, 0.31; 95 percent confidence interval, 0.18 to 0.53; P<0.001). During the follow-up period of about 10 months, 32 percent of the patients in the clarithromycin group died and 41 percent of those in the placebo group died (hazard ratio, 0.75; P=0.026). In the clarithromycin group, isolates from 11 of the 19 patients with M. avium complex infection were resistant to clarithromycin. Prophylaxis with clarithromycin was associated with an increased incidence of taste perversion (11 percent in the clarithromycin group vs. 2 percent in the placebo group, P<0.001) and rectal disorders (8 percent vs. 3 percent, P = 0.007); however, the frequency of more severe adverse events was similar in the two groups (7 percent and 6 percent, respectively). CONCLUSIONS: In patients with advanced AIDS, the prophylactic administration of clarithromycin is well tolerated, prevents M. avium complex infection, and reduces mortality.

Clarithromycin or rifabutin alone or in combination for primary prophylaxis of Mycobacterium avium complex disease in patients with AIDS: A randomized, double-blind, placebo-controlled trial. The AIDS Clinical Trials Group 196/Terry Beirn Community Programs for Clinical Research on AIDS 009 Protocol Team.

The efficacy and safety of clarithromycin and rifabutin alone and in combination for prevention of Mycobacterium avium complex (MAC) disease were compared in 1178 patients with AIDS who had < or =100 CD4 T cells/microL in a randomized, double-blind, placebo-controlled trial. MAC disease occurred in 9%, 15%, and 7% of those randomized to clarithromycin or rifabutin alone or in combination, respectively; time-adjusted event rates per 100 patient-years (95% confidence interval [CI]) were 6.3 (4.2-8.3), 10.5 (7.8-13.2), and 4. 7 (2.9-6.5). Risk of MAC disease was reduced by 44% with clarithromycin (risk ratio [RR], 0.56; 95% CI, 0.37-0.84; P=.005) and by 57% with combination therapy (RR, 0.43; 95% CI, 0.27-0.69; P=. 0003), versus rifabutin. Combination therapy was not more effective than clarithromycin (RR, 0.79; 95% CI, 0.48-1.31; P=.36). Of those in whom clarithromycin or combination therapy failed, 29% and 27% of MAC isolates, respectively, were resistant to clarithromycin. There were no survival differences. Clarithromycin and combination therapy were more effective than rifabutin for prevention of MAC disease, but combination therapy was associated with more adverse effects (31%; P<.001).