Open AccessLoop-Mediated Isothermal Amplification Method Targeting the lytA Gene for Detection of Streptococcus pneumoniae
Author(s) -
Mitsuko Seki,
Yoshihisa Yamashita,
Hirotaka Torigoe,
Hiromasa Tsuda,
Setsuko Sato,
Masao Maeno
Publication year - 2005
Publication title -
journal of clinical microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.349
H-Index - 255
eISSN - 1070-633X
pISSN - 0095-1137
DOI - 10.1128/jcm.43.4.1581-1586.2005
Subject(s) - streptococcus oralis , streptococcus mitis , loop mediated isothermal amplification , streptococcus pneumoniae , microbiology and biotechnology , primer (cosmetics) , biology , streptococcaceae , polymerase chain reaction , streptococcus , virulence , gene , dna , bacteria , chemistry , genetics , organic chemistry , antibiotics
It is difficult to separate Streptococcus pneumoniae from the genotypically similar species Streptococcus mitis and Streptococcus oralis, which are commensals of the human oral cavity. A novel nucleic acid amplification technique, loop-mediated isothermal amplification (LAMP), which amplifies DNA under isothermal conditions (63 degrees C) with high specificity, efficiency, and rapidity, was examined regarding its applicability for detecting S. pneumoniae. An S. pneumoniae-specific LAMP primer targeting the lytA gene was designed. The primer specificity was validated using 10 Streptococcus and 7 non-Streptococcus species. Within 60 min, the assay could detect 10 or more copies of purified S. pneumoniae DNA with a sensitivity 1,000 times that of conventional PCR. Clinical isolates of 21 other strains (3 S. oralis, 17 S. mitis, and 1 Streptococcus species) that harbor virulence-factor-encoding genes (lytA or ply) were tried to differentiate S. pneumoniae. The detection of S. pneumoniae in clinical isolates was more selective using the LAMP method than using conventional PCR. Therefore, LAMP appears to be a sensitive and reliable means of diagnosing S. pneumoniae infection.