Herpes simplex virus resistant to acyclovir: A single-centre experience from the Czech Republic.

Introduction and Aim: Infections caused by herpes simplex viruses (HSV) are frequent in the human population. Because of the widespread use of long-term treatment or prophylaxis by anti-herpetic antivirals in various specific medical contexts (immunosuppression, recurrent infections), the level of antiviral resistance is increasing. According to previous studies, there is a low resistance level in immunocompetent populations but a relatively high level in populations with immunodeficiency. However, there has been no study from the Czech Republic. This study presents results of a single-centre retrospective study from the Czech Republic.
Materials and Methods: Deep frozen DNA from patients with suspected clinical antiviral failure over a long time period (2009-2016) - a total of 15 isolates of HSV1 and seven of HSV2 - were examined for the presence of mutations associated with antiviral resistance. Sequence analysis was performed using an ABI PRISM 3500xL Genetic Analyzer (Applied Biosystems®).
Results: There were no mutations associated with resistance to antivirals inside the UL23 gene in HSV1 isolates. However, resistant mutation D672N (nucleotide change G2014A) was found inside the UL30 gene in seven of the isolates. One mutation associated with resistance to acyclovir (M183stop) was found inside the UL23 gene in one HSV2 isolate. Resistant mutation E678G (nucleotide change A2033G) was identified inside the UL30 gene in six of the HSV2 isolates.
Conclusions: This study confirmed the presence of resistance mutations within the Czech population, but it will be necessary to examine a higher number of isolates for further conclusions.
(Copyright © 2019 International Society for Antimicrobial Chemotherapy. Published by Elsevier Ltd. All rights reserved.)