Susceptibility testing. Viral pathogens

The control of the global expansion and proliferation of the AIDS pandemic has been complicated by the emergence of resistant strains of HIV-1 to the many new antiviral drugs directed to the genes coding for reverse transcriptase and protease enzymes of the virus. Similarly, new drug regimens for the management of chronic hepatitis B and C infections have been complicated by the lack of sustained clinical responses recently associated with either nucleotide mutation (HBV) or specific genotype of the virus (HCV). Commercial systems for performing and interpreting genotypic analysis will facilitate the recognition of informative mutations, standardize results between laboratories, and produce informative and interpretative result formats for optimal treatment of patients. Drug-resistant strains of herpesviruses (HSV, VZV, CMV) are generally associated with prolonged treatment of these infections in immunocompromised patients. Ultimate relevance of genotypic assays for routine clinical practice will require correlation with phenotypic results and the outcomes of long-term studies associating clinical improvement with antiviral drugs with specific mutation patterns of these viruses.