Optimized DNA extraction protocol for Staphylococcus aureus strains utilizing liquid nitrogen.

DNA extraction is crucial for conducting procedures, such as whole-genome sequencing, which demand methods that are reproducible and cost-effective. Lysing Staphylococcus aureus cells is particularly challenging due to their peptidoglycan layer that is resistant to common treatments. Traditional methods involve costly enzymatic lysis using lysostaphin. Here, we developed a novel approach for lysis utilizing liquid nitrogen and mechanical disruption in a mortar. DNA from S. aureus USA300 and related clinical isolates were purified using phenol-chloroform extraction followed by precipitation. The integrity and purity of DNA were confirmed, obtaining suitable concentration and purity for various molecular biology techniques. The quality of the employed DNA was validated by amplifying fragments of different genes using PCR. This method circumvents lysostaphin, yielding DNA that is suitable for use in other techniques.