An improving DNA isolation method for identification of anaerobic bacteria in human colostrum and faeces samples

The efficiency, with which the lysis of 20 anaerobic bacterial samples [8 different bacterial species isolated from 4 colostrum and 4 infants (which are fed only by breast milk and from 3 to 30-day-old) faeces] were lysed, was tested using a reference or an improving method that involves higher levels of lysozyme (Sigma-Aldrich) and proteinase K solution (Sigma-Aldrich). Eight species were lysed with the efficiency of > 87% by the reference methods. Also, the lytic efficiency for Bifidobacterium bifidum BB-12 was > 90%. Accordingly, since the DNA samples isolated by the improved methods can reflect nearly the true genomic information in the microbial flora, the improved methods should be appropriate for genomic analyses, that is, not only for bacteria in the human intestine, but also for bacteria in other human samples, such as colostrum. The study reports that the extraction method used to produce DNA of suitable quantity and quality for subsequent PCR is based on detection applications. The procedures are reliable and reproducible, in typically planning a success rate of over 90%. In summary, it develops a fast and reliable genomic DNA extraction protocol for anaerobic bacteria.