Determinación de la sensibilidad a los antivíricos de las cepas de herpesvirus aisladas de muestras clínicas. Puesta a punto y evaluación de las técnicas

Abstract

Objectives: Standarize the plaque reduction assay (PRA), to study in vitro susceptibility to ganciclovir (GCV) and foscarnet (FOS) of human herpesvirus type 5 (HHV-5) strains and to aciclovir (ACV) and FOS of human herpesvirus type 3 (HHV-3) strains. Standarize the cytopathic effect reduction assay (CRA) and the dye-uptake assay (DUA), to study in vitro susceptibility to ACV and FOS of human herpesvirus types 1 and 2 (HHV-1 and HHV-2) strains. Analize the antiviral susceptibility values obtained with the HHV-1, 2 and 5 strains to compare with the clinical evolution of the patients after treatment. Material and methods: We studied the susceptibility of 204 HHV-1 y 2 strains isolated from different samples isolated from 165 immunosuppressed patients. Antiviral susceptibility values are expressed as the 50 per cent inhibitory dose (ID50). When the antiviral susceptibility was determined by CRA we used the Spearman-Kärber method to calculate the ID50 and with the DUA we determined this value, statistically, using a linear stimation. We studied the susceptibility of 80 HHV-5 strains isolated from the samples of 73 patients with o without underlying disease. Finally, we studied the susceptibility of nine HHV-3 strains isolated from the samples recovered from the skin lesions of nine patients. The ID50 values were determined using the Reed-Muench modified method. Results: Approximately 96% of HHV-1 and 2 strains were inhibited by ACV ID50 values lower than 3 mg/ml. All the strains were susceptible to FOS ID50 values lower than 200 mg/ml. Ninety eight per cent of HHV-5 strains were inhibited by GCV ID50 values lower than 12 mM and by FOS ID50 values lower than 400 mM. All the HHV-3 strains were susceptible to ACV and FOS. Conclusions: 1 - The CRA is easy to perform and can be used to study the susceptibility of HHV-1 and 2. 2 - The reproducibility of the CRA is about 87%. 3 - The addition of vital dye to the CRA adds complexity to this assay. 4 - The values obtained with CRA and PRA had a close correlation with the clinical outcome of patients. 5 - The frequency of HHV-1 and 2 resistant to ACV in immunosuppressed patients is low (4%) and when it's observed not necessarily indicates therapeutic failure. 6 - The PRA is easy to perform the study of susceptibility of HHV-5 and 3 and needs between six and eight weeks to obtain results limiting parcially its clinical utility. 7 - The frequency of HHV-5 strains in vitro resistant to GCV (4%) and to FOS (4%) is low in patients no treated previously. 8 - We didn't detect any HHV-3 strain resistant to ACV or to FOS. 9 - In our experience, there is no need to routinely test susceptibility of HHV-1 and 2 isolated to ACV. Study of HHV-1 and 2 susceptibility should be indicated only in viruses isolated from patients with a severe immunologic disturbance in whom lesions persist or worsen while on ACV therapy.

Date of Award	15 Feb 2002
Original language	Undefined/Unknown
Supervisor	Núria Rabella García (Director)