Cytomegalovirus resistance testing: pitfalls and problems for the clinician

Area of Science:

• Virology
• Clinical Microbiology
• Pharmacology

Background:

• Cytomegalovirus (CMV) infections pose significant risks, especially in immunocompromised individuals.
• Antiviral therapy is crucial for managing CMV disease, but resistance can compromise treatment efficacy.
• Monitoring antiviral resistance is essential for guiding clinical management and optimizing patient outcomes.

Purpose of the Study:

• To review available diagnostic assays for detecting CMV antiviral resistance.
• To emphasize the practical utility and application of genotypic resistance testing.
• To discuss the clinical indications, contraindications, and interpretation of resistance test results.

Main Methods:

• Literature review of published studies on CMV antiviral resistance detection methods.
• Analysis of the advantages and limitations of phenotypic and genotypic assays.
• Synthesis of information regarding cross-resistance patterns among different antiviral agents.

Main Results:

• Genotypic assays offer a practical and widely applicable approach for detecting CMV antiviral resistance.
• Specific genetic mutations in CMV genes (e.g., UL97, UL54) are associated with resistance to commonly used antivirals.
• Phenotypic assays provide complementary information but are less frequently used in routine clinical practice.

Conclusions:

• Genotypic resistance testing is a valuable tool for guiding antiviral therapy in CMV infections.
• Understanding resistance mechanisms and cross-resistance is critical for effective treatment strategies.
• Standardized interpretation of genotypic results is necessary to ensure accurate clinical decision-making.