PCR-Sequencing for Detection of Human Cytomegalovirus Mutations Conferring Antiviral Resistance

  • Gillian M. Scott


Antiviral resistant strains will emerge in at least 10% of patients receiving long-term antiviral therapy for the prevention or treatment of cytomegalovirus (CMV) infection and disease. Prophylaxis therapy with the antiviral agent valganciclovir (the oral pro-drug of ganciclovir) is becoming a common strategy for the prevention of CMV infection in immunocompromised transplant recipients, and accordingly, requests for CMV antiviral resistance testing are also increasing. The antiviral agents cidofovir and foscarnet are also used against ongoing CMV infection and disease when ganciclovir or valganciclovir therapy has failed, but resistance to these compounds can also develop. The most accurate, sensitive and comprehensive approach for identification of antiviral resistant CMV strains is PCR-sequencing, where segments of the CMV UL97 and UL54 genes are amplified by nested PCR and the PCR products sequenced [1, 2]. Mutations that confer antiviral resistance to CMV strains occur in specific regions of UL97 and UL54, and therefore only specific segments of these genes (one segment for UL97 and two for UL54) need to be amplified and sequenced, increasing the overall sensitivity and specificity of the assay. In combination, sequencing of these three PCR products allows the identification of all mutations known to confer resistance to ganciclovir and valganciclovir, as well as foscarnet and cidofovir, including DNA polymerase mutations that can confer cross-resistance to two or more of these compounds. This information is highly valuable to clinicians trying to determine a course of action where CMV-positive patients fail to respond to the antiviral agent they have been administered.


Antiviral Agent UL54 Gene Antiviral Resistance Prophylaxis Therapy UL54 Mutation 
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    Iwasenko J, Scott G, Zeigler J et al (2007) Emergence and persistence of multiple antiviral-resistant CMV strains in a highly immunocompromised child. J Clin Virol 40:152–155PubMedCrossRefGoogle Scholar
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    Scott GM, Isaacs MA, Zeng F et al (2004) Cytomegalovirus antiviral resistance associated with treatment induced UL97 (protein kinase) and UL54 (DNA polymerase) mutations. J Med Virol 74(1):85–93PubMedCrossRefGoogle Scholar
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    Scott GM, Weinberg A, Rawlinson WD et al (2007) Multi-drug resistance conferred by novel DNA polymerase mutations in human cytomegalovirus isolates. Antimicrob Agents Chemother 51(1):89–94PubMedCrossRefGoogle Scholar
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    Chou S, Lurain NS, Thompson KD et al (2003) Viral DNA polymerase mutations associated with drug resistance in human cytomegalovirus. J Infect Dis 188(1): 32–39PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2010

Authors and Affiliations

  1. 1.Virology Division, Department of MicrobiologySEALS, Prince of Wales Hospital and School of Biotechnology and Biomolecular SciencesRandwickAustralia
  2. 2.University of New South WalesSydneyAustralia

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