Amplification techniques for detection of herpes simplex virus in neonatal and maternal genital specimens obtained at delivery

Physical and chemical methods for enhancing rapid detection of viruses and other agents

Viral replication events can be enhanced by physical, chemical, or heat treatment of cells. The centrifugation of cells can stimulate them to proliferate, reduce their generation times, and activate gene expression. Human endothelial cells can be activated to release cyclo-oxygenase metabolites after rocking for 5 min, and mechanical stress can stimulate endothelial cells to proliferate. Centrifugation of virus-infected cultures can increase cytopathic effects (CPE), enhance the number of infected cells, increase viral yields, and reduce viral detection times and may increase viral isolation rates. The rolling of virus-infected cells also has an effect similar to that of centrifugation. The continuous rolling of virus-infected cultures at < or = 2.0 rpm can enhance enterovirus, rhinovirus, reovirus, rotavirus, paramyxovirus, herpesvirus, and vaccinia virus CPE or yields or both. For some viruses, the continuous rolling of infected cell cultures at 96 rpm (1.9 x g) is superior to rolling at 2.0 rpm for viral replication or CPE production. In addition to centrifugation and rolling, the treatment of cells with chemicals or heat can also enhance viral yields or CPE. For example, the treatment of virus-infected cells with dimethyl sulfoxide can enhance viral transformation, increase plaque numbers and plaque size, increase the number of cells producing antigens, and increase viral yields. The infectivity of fowl plague virus is increased by 80-fold when 4% dimethyl sulfoxide is added to culture medium immediately after infection. The heat shocking of virus-infected cells also has been shown to have a stimulatory effect on the replication events of cytomegalovirus, Epstein-Barr virus, and human immunodeficiency virus. The effects of motion, chemicals, or heat treatments on viral replication are not well understood. These treatments apparently activate cells to make them more permissive to viral infection and viral replication. Perhaps heat shock proteins or stress proteins are a common factor for this enhancement phenomenon. The utility of these treatments alone or in combination with other methods for enhancing viral isolation and replication in a diagnostic setting needs further investigation.

Evaluation of a visual, rapid, membrane enzyme immunoassay for the detection of herpes simplex virus antigen

We evaluated a 12-min, direct, monoclonal antibody-based enzyme immunoassay (EIA) (SureCell; Kodak, Rochester, N.Y.) which aids in the detection of herpes simplex virus infection; the assay system is also approved for culture confirmation. The test was evaluated from direct clinical samples and compared with conventional culture methodology by using a single swab. A total of 265 specimens from 180 female cervical-urogenital sites, 62 male urogenital sites, 4 rectal sites, 3 skin sites, 6 oral sites, and 10 colposcopy sites were collected on Dacron or cotton swabs and placed in viral transport medium (VTM). Within 6 h of receipt, 0.2 ml of the vortexed VTM was inoculated into each of two replicate cell cultures. Cell monolayers were observed daily for ten days, and cytopathic effect was confirmed by using an indirect immunoperoxidase reagent. The procedure for the SureCell assay conformed to the manufacturer's recommendations. When conventional culture was compared with EIA results, the overall sensitivity, specificity, positive predictive value, negative predictive value, and agreement were 64.4, 98.9, 96.7, 84.4, and 87.2%, respectively. Variables affecting the EIA sensitivity are the stage of the lesion and conventional culture methodologies. A review of culture results for 32 EIA false-negative tests indicated that 15 were detected after 48 h of incubation. Cytopathic effect observed at 48-, 72-, and 96-h cutoffs altered the sensitivity for the EIA. To ensure detection of SureCell herpes simplex virus-negative specimens, it is recommended that an unused aliquot of VTM be tested in cell culture.

Detection of herpes simplex virus by the Kodak SureCell Herpes Test

The Kodak SureCell Herpes Test Kit (SC-HSV) was evaluated in a high-risk sexually transmitted disease clinic population. A total of 97 lesion specimens (from 94 patients) were tested for the presence of herpes simplex virus by SC-HSV and by spin-amplified tissue culture confirmed by an enzyme immunoassay. The overall sensitivity of SC-HSV compared with that of spin-amplified tissue culture-enzyme immunoassay was 81.1%; the specificity was 100%. For vesicular lesions only, SC-HSV sensitivity was 100%; for nonvesicular lesions, sensitivity was 75.6%, SC-HSV was rapid (less than 15 min) and very easy to perform.

Comparison of enzyme immunoassay, shell vial culture, and conventional cell culture for the rapid detection of herpes simplex virus

Specimens submitted for the detection of herpes simplex virus (HSV) were inoculated into conventional cell-culture tubes and fresh MRC-5 shell vials. The shell vial centrifugation cultures (SVCs) were examined at 16 hr postinoculation for HSV by using type-specific monoclonal antibodies (SVC-FA); they were also analyzed for HSV antigen by using an enzyme-linked immunoassay (SVC-ELISA). Mink Lung (ML) and rhabdomyosarcoma (RD) cells were used in the cell-culture tubes. Of 182 specimens, 35 (19%) were positive in cell-culture tubes, 16 (9%) were positive by SVC-ELISA, and 22 (12%) were positive SVC-FA. All specimens that were positive by SVC-ELISA, SVC-FA, and in culture tubes displayed cytopathic effect (CPE) at 16 hr. Those specimens that had a negative ELISA and/or FA result and were positive in culture were evaluated for the time in which it took to detect CPE. At 16 hr, 48% of the positive tubes were detected; at 40 hr (second day), 83% of the positive tubes were detected; and by the third day, 94% were detected. The RD cell line displayed CPE at the same time or earlier than ML cells did in 92% of the positive cases. The sensitivity of the SVC-ELISA at 16 hr was 46% with 100% specificity. The sensitivity of the SVC-FA at 16 hr was 63% with 99% specificity. Given the increased sensitivity, rapid display of CPE, and reduced cost and handling time of cell cultures, our laboratory found that rapid SVC-ELISA and SVC-FA procedures for HSV detection have no clinical or laboratory advantage.