Resistance
Acyclovir-resistant HSV occurs mainly in immunocom- promised patients treated with the drug; isolates are usually also resistant to valacyclovir and famciclovir. Resistant HSV infection in HIV-positive patients has been associated with progressive mucosal disease and, rarely, visceral involvement. Acyclovir-resistant VZV strains in HIV-positive patients have been associated with chronic cutaneous lesions and, rarely, invasive disease.