title: Rapid ganciclovir susceptibility assay using flow cytometry for human cytomegalovirus clinical isolates.
abstract: Rapid, quantitative, and objective determination of the susceptibilities of human cytomegalovirus (HCMV) clinical isolates to ganciclovir has been assessed by an assay that uses a fluorochrome-labeled monoclonal antibody to an HCMV immediate-early antigen and flow cytometry. Analysis of the ganciclovir susceptibilities of 25 phenotypically characterized clinical isolates by flow cytometry demonstrated that the 50% inhibitory concentrations (IC50s) of ganciclovir for 19 of the isolates were between 1.14 and 6.66 microM, with a mean of 4.32 microM (+/-1.93) (sensitive; IC50 less than 7 microM), the IC50s for 2 isolates were 8.48 and 9.79 microM (partially resistant), and the IC50s for 4 isolates were greater than 96 microM (resistant). Comparative analysis of the drug susceptibilities of these clinical isolates by the plaque reduction assay gave IC50s of less than 6 microM, with a mean of 2.88 microM (+/-1.40) for the 19 drug-sensitive isolates, IC50s of 6 to 8 microM for the partially resistant isolates, and IC50s of greater than 12 microM for the four resistant clinical isolates. Comparison of the IC50s for the drug-susceptible and partially resistant clinical isolates obtained by the flow cytometry assay with the IC50s obtained by the plaque reduction assay showed an acceptable correlation (r2 = 0.473; P = 0.001), suggesting that the flow cytometry assay could substitute for the more labor-intensive, subjective, and time-consuming plaque reduction assay.
authors.affiliation: Albany Medical College, Albany, New York 12208, USA. jim_mcsharry@ccgateway.amc.edu
authors.forename: J J
authors.initials: JJ
authors.lastname: McSharry
authors.forename: N S
authors.initials: NS
authors.lastname: Lurain
authors.forename: G L
authors.initials: GL
authors.lastname: Drusano
authors.forename: A L
authors.initials: AL
authors.lastname: Landay
authors.forename: M
authors.initials: M
authors.lastname: Notka
authors.forename: M R
authors.initials: MR
authors.lastname: O'Gorman
authors.forename: A
authors.initials: A
authors.lastname: Weinberg
authors.forename: H M
authors.initials: HM
authors.lastname: Shapiro
authors.forename: P S
authors.initials: PS
authors.lastname: Reichelderfer
authors.forename: C S
authors.initials: CS
authors.lastname: Crumpacker
mesh_terms: D000956:Antigens, Viral / Q000096:biosynthesis; D000998:Antiviral Agents / Q000494:pharmacology*; D003587:Cytomegalovirus / Q000187:drug effects*; D005434:Flow Cytometry; D015774:Ganciclovir / Q000494:pharmacology*; D006801:Humans; D017874:Immediate-Early Proteins / Q000096:biosynthesis
chemical_list: D000956:Antigens, Viral; D000998:Antiviral Agents; D017874:Immediate-Early Proteins; C044582:immediate-early proteins, cytomegalovirus; D015774:Ganciclovir