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Current guidelines suggest that disseminated Mycobacterium avium complex (MAC) infection be treated with a macrolide plus ethambutol or rifabutin or both. From 1993 to 1996, 198 AIDS patients with MAC bacteremia participated in a prospective, placebo-controlled trial of clarithromycin (500 mg b.i.d.) plus ethambutol (1,200 mg/d), with or without rifabutin (300 mg/d). At 16 weeks, 63% of patients in the rifabutin group and 61% in the placebo group (P = .81) had responded bacteriologically. Changes in clinical symptoms and time to survival were similar in both groups. Development of clarithromycin resistance during therapy was similar in the two groups; of patients who had a bacteriologic response, however, only 1 of 44 (2%) receiving rifabutin developed clarithromycin resistance, vs. 6 of 42 (14%) in the placebo group (P = .055). Thus, rifabutin had no impact on bacteriologic response or survival but may protect against development of clarithromycin resistance in those who respond to therapy.

The in vitro susceptibilities of baseline Mycobacterium avium complex (MAC) blood isolates from 86 patients with AIDS who were treated with clarithromycin, ethambutol, and rifabutin were determined to examine whether these results predict bacteriologic response to treatment. No patient received prior prophylaxis with clarithromycin or azithromycin. Minimum inhibitory concentrations (MICs) of clarithromycin for all isolates were < or = 2 micrograms/mL. The median MIC of rifabutin was between 0.25 and 0.5 microgram/mL, and all isolates were susceptible to < or = 2 micrograms of rifabutin/mL. The median MIC of ethambutol was 4 micrograms/mL, and the MIC90 was 8 micrograms/mL. There was no correlation between ethambutol susceptibility and subsequent bacteriologic clearance. At all time points through week 12, bacteriologic clearance occurred more frequently in patients with isolates for which MICs of rifabutin were lower, but this difference was statistically significant only at week 2. Susceptibility testing for baseline MAC isolates from AIDS patients not previously treated with clarithromycin or azithromycin does not appear to be useful in guiding therapy.

One hundred thirty-five cases of infective endocarditis in adults at the University of Alberta Hospital from 1985 to 1993 were reviewed and the von Reyn and Duke criteria were compared. There were 80 cases of native valve endocarditis, 15 cases of endocarditis in intravenous drug users, 7 cases of early prosthetic valve endocarditis, and 33 cases of late prosthetic valve endocarditis. Valve replacement or repair was performed in 33% of all cases. The overall mortality was 19%. The mortality among patients treated surgically was significantly lower than that among those treated medically (9% vs. 24%, respectively; P = .037). However, when patients who were too medically unstable for surgery or who refused surgery were excluded, the mortality among the medically treated group decreased to 15%, which was not significantly different from that among the surgically treated group. The 33 patients transferred from other hospitals were infected with similar pathogens; however, the rate of surgical intervention among these patients was much higher than that among other patients (64% vs. 24%, respectively; P < .0001), and the mortality was slightly lower (12.1% vs. 21.6%, respectively; P = .31). The 54 surgical and autopsy-proven cases were classified by the von Reyn and the Duke criteria without knowledge of the operative and autopsy results: 15% of these cases were rejected by the von Reyn criteria, and none were rejected by the Duke criteria.

Esophagitis due to herpes simplex virus is a well-recognized entity in immunocompromised patients but has only rarely been described in apparently immunocompetent hosts. We report four cases and review 27 additional cases identified in the English-language literature. Odynophagia, retrosternal chest pain, and fever are the most common symptoms. Single-contrast esophagography is insensitive and nonspecific, but double-contrast esophagography may be of more diagnostic value. Esophagoscopy with biopsy or collection of aspirate for cytologic examination and culture are required to make a definitive diagnosis. Patients are predominantly male, and most cases are associated with primary infection. Viral isolates were typed in 13 cases and were always type 1. Herpes simplex esophagitis in the immunocompetent patient is a self-limited infection; however, therapy with acyclovir may attenuate infection and hasten resolution of symptoms.