The reculture technique: individualizing the treatment of Acanthamoeba keratitis.

PURPOSE: To assess the efficacy of three drugs in different concentrations against different strains of Acanthamoeba using the reculture technique. METHODS: Cysts and trophozoites were immersed in five separate solutions. The solutions administered included 0.1% and 0.02% polyhexamethylene biguanide (PHMB), 0.1% and 0.02% chlorhexidine, and propamidine isethionate (Brolene). Readings took place after 1, 5, and 24 hours. The cysts and trophozoites were then recultured for an additional period of 48 hours. An effective drug was defined as a medication that inhibited any growth of trophozoites using the reculture technique. RESULTS: Chlorhexidine at concentrations of 0.1% and 0.02% was the only effective drug against all five strains of Acanthamoeba examined, and no trophozoites were detected on plates immersed with this agent. Only 0.1% chlorhexidine was effective in destroying all cysts in the five strains examined. CONCLUSION: We found that 0.02% chlorhexidine was efficient in irradicating all trophozoites and 0.1% chlorhexidine was effective in eradicating all cysts in the samples we examined. Therefore, it may be possible that 0.02% chlorhexidine is a good initial treatment in amoebic keratitis. Sensitivity testing, then, may be performed using the reculture technique and specification of therapy can be made accordingly.

Successful treatment of disseminated Mycobacterium simiae infection in AIDS patients.

Mycobacterium simiae is rarely isolated in clinical settings of non-HIV-infected patients. Isolation of M. simiae from clinical specimens in clusters has been limited to some parts of the world that include Israel, Cuba and the southern USA, mainly Texas. Only 8 patients with HIV and disseminated M. simiae infection have been previously described in the English literature. Successful treatment of disseminated M. simiae infection has never been reported and 6 of the cases have died within 8 months of diagnosis. We reviewed retrospectively the medical records of HIV-infected patients who had positive blood or bone marrow cultures for M. simiae at the Sheba Medical Center, Tel-Hashomer, Israel, between January 1992 and December 1996. A case of disseminated M. simiae infection was defined as isolation of M. simiae in blood or bone marrow culture in an HIV-infected patient with a compatible, otherwise unexplained, systemic disease. Mycobacterium simiae was isolated in blood and/or bone marrow cultures from 3 HIV-infected patients during the last 5 y. We describe the first successful treatment in AIDS patients with disseminated M. simiae infection. The patients are alive and well 20 months after instituting a combination of 3 antimycobacterial agents, clarithromycin, ethambutol and ciprofloxacin and intensive antiretroviral therapy.

[Acanthamoebic keratitis].

Acanthamoebic keratitis is still a rare infection. It occurs in contact lens-wearers, especially when saline is prepared at home from contaminated tap water. There are periods of remission, and occasionally misleading findings resembling those of herpetic keratitis, which make the diagnosis difficult. The isolation of the acanthamoeba is not easy and special culture media are required. Early recognition and aggressive therapy with antiamebic medication and epithelial debridement, often in conjunction with penetrating keratoplasty, are needed. We describe the clinical course, laboratory diagnosis and treatment of 3 patients with acanthamoebic keratitis, 2 men aged 20 and 25, respectively and a women aged 42.