P036

1:Duke-NUS Medical School; 2:Singapore General Hospital

Genomic nucleic acid amplification and species identification of microorganisms require high quality DNA. Since 2011, our lab been using the INNO-LiPA Mycobacteria v2 (INNO-LiPA) to identify nontuberculous mycobacteria isolated from clinical samples.  DNA is extracted using Heat-Sonication, which involves a 45min heat-inactivation and a 15min sonication process.  With increased number of nontuberculous mycobacteria being isolated, a more rapid DNA extraction method would be advantageous. The GenoLyse (Hain Lifescience, Germany) method only requires a 5min lysis time and a buffer neutralization step. Therefore, this study aimed to compare the INNO-LiPA performance and mycobacteria inactivation efficacy between the Heat-Sonication and GenoLyse extraction methods.  A total of 61 bacterial isolates (18 reference strains and 43 clinical isolates) were subjected to DNA extraction, using both methods for a pairwise evaluation. The INNO-LiPA and result interpretation were conducted following the manufacturer’s instructions. Although the Heat-Sonication method yielded a 3.35-fold higher (p value 0.0004) DNA concentration than the GenoLyse method, the latter produced a 1.45-fold higher (p value 0.000003) amplicon concentration than the former. Despite the significant differences, analytes amplified from Heat-Sonication and GenoLyse extraction methods demonstrated comparable performances with an assay sensitivity of 96.42% and 98.18%, respectively. The assay specificity was 100% for both extraction methods. The inactivation efficiency was also comparable, with 98.36% (60/61) by Heat-Sonication and 100% (61/61) by the GenoLyse method. In conclusion, the GenoLyse method was shown to be a rapid DNA extraction method that provides comparable INNO-LiPA identification performance when compared to that of Heat-Sonication extraction method.