A retrospective, case-control study of acyclovir resistance in herpes simplex virus.

Clinical Infectious Diseases

PubMedID: 16007528

Malvy D, Treilhaud M, Bouée S, Crochard A, Vallée D, El Hasnaoui A, Aymard M, RESSAC Study Group. A retrospective, case-control study of acyclovir resistance in herpes simplex virus. Clin Infect Dis. 2005;41(3):320-6.
BACKGROUND
Occasional cases of acyclovir resistance have been documented in the treatment of herpes simplex virus (HSV) infection. Thirty-eight subjects with acyclovir-resistant infections were identified in an epidemiological surveillance program involving 1811 HSV-infected subjects in France.

METHODS
Twenty-three index cases from whom acyclovir-resistant HSV strains had been isolated were compared with 46 control subjects matched for immunological status. Sociodemographic characteristics, features of the acyclovir-resistant HSV episode, history of HSV infection, treatment, outcome, and immunological history were recorded.

RESULTS
Twenty-two index case patients presented with immunodepression. Sixty-five percent reported clinically manifest recurrences, compared with 33% of matched control subjects. Significantly more index case patients had used antiviral drugs, and they had used them more often than had control subjects. However, 26.1% of index case patients reported no antiviral exposure in the previous 2 years. Two-thirds of the strains recovered from the index case patients were isolated because of suspicion of clinical resistance to acyclovir.

CONCLUSIONS
Clinical treatment resistance is associated with acyclovir-resistant HSV strains, but acyclovir-resistant strains were also isolated from treatment-naive subjects.