Detection and typing of molluscum contagiosum virus in skin lesions by using a simple lysis method and polymerase chain reaction.

A polymerase chain reaction (PCR) assay for the rapid detection and typing of molluscum contagiosum virus (MCV) was developed. The target DNA was a 393 base pair (bp) segment, which is present in the coding region of the MCV p43K gene product. Release of MCV DNA from skin lesions was performed by using a simple procedure that provided suitable template DNA for amplification, and allowed detection of MCV directly in clinical material. The PCR yielded a unique 393 bp product when MCV DNA was used as template. This product was not shown with DNA from other viruses and bacterial pathogens causing skin diseases. The specific PCR product was obtained with individual lesions from all patients clinically diagnosed with MCV infection, whereas no products were detected with skin samples from healthy individuals. Sequencing of this PCR product allowed determination of the virus subtype on the basis of previously described nucleotide differences between subtypes MCVI and MCVII. To avoid the sequencing process, a second PCR assay was developed, in which the target DNA sequence included a MCVI-specific recognition site for the restriction endonuclease BamHI. This PCR assay yielded a unique 575 bp product with lesions from either MCVI- or MCVII-infected patients. However, only the MCVI-derived product was susceptible to BamHI digestion, which generated two fragments of 291 and 284 bp, respectively. Amplification of specific MCV DNA sequences from single, individual lesions provides a sensitive and reliable method for laboratory diagnosis and molecular epidemiology studies of molluscum contagiosum.