Rapid detection of cytomegalovirus in clinical specimens by immunofluorescent staining of shell vial cultures

A recently described rapid technique for detection of cytomegalovirus (CMV) was evaluated in clinical specimens utilizing indirect immunofluorescent staining (IFA) of shell vial cultures. A total of 266 clinical specimens received for viral isolation were inoculated to commercially available shell vials seeded with human lung fibroblasts (MRC-5), centrifuged at 700 X g for one hour, and stained after 18 hours incubation with monoclonal antibody to CMV early nuclear protein (Biotech Research Laboratories) and fluorescein conjugated goat antimouse IgG (Cappel Laboratories). All specimens were also inoculated to tubes of human lung fibroblasts and observed for cytopathic effect (CPE) for 28 days. Of 54 specimens positive for CMV, 36 were positive by both IFA and CPE, 3 were positive by CPE only, and 15 were positive by IFA only (P less than 0.01 by the chi-square test). Failure to detect CMV associated CPE in 10 of these 15 samples was probably due to concomitant infection with herpes simplex virus or heavy bacterial or fungal contamination. Nine of the 13 patients with IFA-positive CPE-negative specimens had CMV infection documented by other positive cultures. It was concluded that the shell vial IFA rapid technique for detection of CMV is highly specific, more sensitive than conventional isolation, and well suited for application in a clinical virology laboratory.