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Rapid detection of varicella–zoster virus infection by a loop‐mediated isothermal amplification method
Author(s) -
Okamoto Souki,
Yoshikawa Tetsushi,
Ihira Masaru,
Suzuki Kayoko,
Shimokata Kaoru,
Nishiyama Yukihiro,
Asano Yoshizo
Publication year - 2004
Publication title -
journal of medical virology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 121
eISSN - 1096-9071
pISSN - 0146-6615
DOI - 10.1002/jmv.20223
Subject(s) - loop mediated isothermal amplification , varicella zoster virus , agarose gel electrophoresis , virology , virus , polymerase chain reaction , dna extraction , biology , microbiology and biotechnology , detection limit , dna , chromatography , chemistry , genetics , gene
The reliability of varicella–zoster virus (VZV) loop‐mediated isothermal amplification (LAMP) was evaluated for rapid diagnosis of viral infection. VZV‐specific primers only amplified VZV DNA; no LAMP products were observed in reactions performed with other viral DNA templates. The specificity of this method was confirmed by two independent determinations, agarose gel electrophoresis and a turbidity assay. The sensitivity of VZV LAMP, determined by agarose gel electrophoresis, were 500 copies/tube. Detection using the turbidity assay, however, gave a sensitivity of 1,000 copies/tube. After these initial validation studies, reliability of VZV LAMP was evaluated for the detection of viral DNA in clinical specimens. Thirty‐two swab samples collected from patients with vesicular skin eruptions were tested for VZV DNA. VZV was confirmed in sample numbers 10–32 by VZV real‐time PCR, a previously established technique. VZV LAMP products were detected using turbidity from samples 13 to 32 (sensitivity; 87.0%, specificity; 100%, positive predictive value; 100%, negative predictive value; 75%). Although low levels of VZV DNA could be detected in the three samples exhibiting divergent results (samples numbers 10–12), no VZV LAMP product was detected in these samples, indicating a higher detection limit for this assay. Requirement of a DNA extraction step in the VZV LAMP method was examined in next experiment. The turbidity assay detected a VZV LAMP product in all of the 20 positive swab samples (samples numbers 13–32), regardless of DNA extraction. J. Med. Virol. 74:677–682, 2004. © 2004 Wiley‐Liss, Inc.