Investigating the effect of microtube capping/decapping methods on Escherichia coli collection contamination:...

This study aimed to evaluate the effect of varying sample volumes (200 μL, 500 μL, and 1000 μL) on the leakage rates of samples between spin-down and non-spin-down conditions for the target genes Tet and uid-A, comparing machine-operated and manual protocols. The study was designed to assess the differences between mechanical versus manual operators handling different-volume specimens. JM109 Escherichia coli suspensions, carrying the plasmid pBR322 and in the logarithmic growth phase, were aliquoted into 1.5-mL microcentrifuge tubes and divided into six groups based on contamination risk (minimal splash contamination and manual handling). The results indicated that the conventional manual and person hand operated methods exhibited the highest incidence of splash contamination, with rates of 95 % and 100 %, respectively. In contrast, methods utilizing advanced software and automated mechanism methods significantly reduced the risk of splashing, with rates of only 10.53 % and 20 %, respectively, in a pairwise comparison. The comparison of different operational methods highlighted the importance of the automated experimental equipment in reducing laboratory contamination resulting from specimen splashing. Automated mechanical operations outperformed manual methodologies across all sample volumes and conditions, demonstrating their effectiveness in enhancing safety and reducing variability caused by operator-dependent factors. These results further emphasize the necessity of implementing automated mechanical systems to improve sample integrity and reduce laboratory contamination risks.