Nested multiplex polymerase chain reaction for the diagnosis of cutaneous herpes simplex and herpes zoster infections and a comparison with electronmicroscopy

Herpes simplex virus (HSV) and varicella tester virus (VZV) are common caus es of cutaneous and mucocutaneous vesicular eruptions. Laboratory diagnosti c techniques include Tzanck smears, electronmicroscopy, antigen detection a nd viral culture. This paper describes a nested multiplex polymerase chain reaction with respective sensitivities of 0.0001, 0.01 and 0.1 TCID50 for V ZV, HSV-1 and HSV-2. The assay was used in (a) a salvage capacity for slide s already processed for electronmicroscopy, and (b) as a front-line assay f or prospectively processed specimens. Sixty-two glass slides with vesicle l ymph/scrapings from 58 patients with suspected cutaneous herpetic lesions w ere examined. The clinical presentations were described as atypical/not spe cified (24), VZV (20) or HSV (18), and involved eruptions from diverse anat omical sites, including the genitalia. Of the 62 specimens, 6 and 38 were p ositive by electronmicroscopy and multiplex PCR respectively, giving a comp arative sensitivity of 16% for electronmicroscopy. Nested multiplex PCR ide ntified 15 VZV and 20 HSV-1 infections. Where the clinical details indicate d either HSV or VZV (38/62), nested multiplex PCR was statistically likely to be reactive (26/38 vs. 9/24) (chi (2) P = 0.000004) whereas electronmicr oscopy was not (4/38 vs. 2/24) (chi (2) P = 0.77). Where the clinical detai ls in dicated VZV (20/62) or HSV (18/62), nested multiplex PCR was statisti cally more likely to confirm VZV (10/20 vs. 5/42) (chi (2) P= 0.001) or HSV (9/18 vs. 11/44) (chi (2) P= 0.05) respectively. Two suspected HSV and 6 s uspected VZV infections were shown to be VZV and HSV respectively by nested multiplex PCR. (C) 2001 Wiley-Liss, Inc.