[Genotyping diagnosis of acyclovir resistant herpes simplex virus]

Area of Science:

• Virology
• Molecular Biology
• Genetics

Context:

• Acyclovir (ACV) resistance in herpes simplex virus (HSV) poses a significant clinical challenge, particularly in immunocompromised individuals.
• Resistance mechanisms primarily involve mutations in the viral thymidine kinase (TK) or DNA polymerase genes.
• Current detection methods rely on phenotypic testing, which is time-consuming (7-10 days).

Purpose:

• To highlight the need for rapid detection of ACV-resistant HSV.
• To discuss the genetic basis of ACV resistance, focusing on TK gene mutations.
• To advocate for the implementation of direct genotyping from clinical samples.

Summary:

• Herpes simplex virus resistance to acyclovir (ACV) is frequently linked to mutations in the thymidine kinase (TK) gene, often occurring in G/C homopolymer regions.
• These mutations can involve insertions, deletions, or substitutions, impacting viral susceptibility.
• Phenotypic resistance testing is slow, delaying appropriate patient management.

Impact:

• Direct genotyping offers a faster alternative for detecting ACV resistance directly from clinical specimens.
• Rapid diagnosis enables prompt switching to alternative antivirals like foscarnet or cidofovir.
• Improved diagnostic turnaround time can optimize treatment strategies for patients with resistant HSV infections.