Fungal endocarditis complicating treatment of prosthetic valve bacterial endocarditis: value of prophylactic oral nystatin.

We describe two patients in whom fungal endocarditis occurred during antibiotic therapy for prosthetic valve bacterial endocarditis. Successful management of both patients was eventually achieved with antifungal therapy and replacement of the prosthetic valves. These cases and review of the literature suggest that (1) high-dose antibacterial therapy predisposes to fungal endocarditis; (2) during prolonged antibiotic therapy in patients predisposed to endocarditis, clinicians should consider the use of oral nystatin as prophylaxis against fungemia and possible fungal endocarditis; and (3) early replacement of prosthetic valves infected with fungi is indicated because chemotherapy alone is predictably inadequate to effect a cure.

Gram-stain neutrality of Mycobacterium tuberculosis.

Although the Gram stain is a frequently used technique, its application to mycobacterial identification is confusing. A recent clinical experience is presented to demonstrate the gram-neutrality of the air-dried bacillus.

Antibiotic susceptibility testing of Bacteroides.

Seventy Bacteroides strains isolated from clinical materials were tested in vitro against nine antibiotics by means of modified disc diffusion and agar dilution tests. Correlating the agar dilution susceptibility with the concentrations achievable in serum for each drug tested, we found that at least 90% of the strains were susceptible to clindamycin, chloramphenicol, carbenicillin, and lincomycin. Only 40% were susceptible to tetracycline. Except for tetracycline and chloramphenicol, the disc diffusion technique exhibited inadequate predictive value in terms of "susceptibility" and "resistance" for the Bacteroides strains tested.