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Determination of the metagenome has become an important component of forensic identification, which requires efficient environmental sampling techniques. Therefore, in this study, we compared the efficiency of sample collection using swabbing with cotton swabs and three types of medical swabs (S7, S22, S24) along with three different solutions: phosphate-buffered saline (PBS), 1% Tween 20 + 1% glycerol in PBS (TG), and GS commercial solution (Noble Bio, Hwaseong, Republic of Korea). Combinations of the three solutions with the three types of swabs were tested at different volumes (cotton swab, S7: 0, 30, 50, 70 μL; S22, S24: 0, 70, 100, 130 μL). Escherichia coli and Staphylococcus aureus were selected as representative environmental microbial samples, and the number of colony-forming units (CFUs), DNA concentration, and DNA copy numbers were compared across groups. The sampling process had a clear effect on the efficiency of extraction, which allowed for determination of a more efficient sample sampling method. In particular, cotton swabs showed 2–10-fold greater CFUs of both species than the medical swabs, and resulted in significantly greater amounts of extracted DNA. TG was found to be the most efficient solution for bacterial DNA extraction, with higher CFUs and DNA obtained than with the other three solutions at all volumes tested. This study highlights the need for a standardized sampling method that can be applied to all environmental samples, especially for microbial quantification, and provides valuable reference data for the efficient collection of environmental samples for metagenomic analyses in microbial-based forensic assessments. • Sampling methods of bacterial DNA from artificial dried samples were compared. • Conventional cotton swabs showed better efficiency than medical swabs. • TG (1% Tween 20 + 1% glycerol in PBS) resulted in the most efficient recovery. • Efficient and standardized sampling can promote metagenomics in forensics analyses. [ABSTRACT FROM AUTHOR]

Although molecular diagnosis has replaced culture as the reference technique in gonococcal infection, conventional culture is still performed. The aim was to compare the survival of Neisseria gonorrhoeae (NG) in transport swabs at room temperature (RT) and at 4 °C. Fifty-four NG isolates were tested. A 1.5 × 10 8 CFU mL − 1 suspension was prepared for each strain, in which two swabs (Amies liquid medium with flocked swabs) were absorbed; one was preserved at RT and the other at 4 °C. At 24 and 48 h, 150 μL of Amies medium were plated in Thayer Martin agar. The recovery percentage was significantly higher for the swabs kept at 4 °C than for those kept at RT, both at 24 h (94.4% vs. 16.7%), and at 48 h (37% vs. 0%). This study clearly demonstrates the higher survival of NG when transport swabs are kept refrigerated. Modifying the guidelines could greatly improve the efficiency of microbiological diagnosis of the gonococcal infection. [ABSTRACT FROM AUTHOR]

Abstract: The Government Accountability Office report investigating the surface sampling methods used during the 2001 mail contamination with Bacillus anthracis brought to light certain knowledge gaps that existed regarding environmental sampling with biothreat agents. Should a contamination event occur that involves non-spore forming biological select agents, such as Yersinia pestis, surface sample collection and processing protocols specific for these organisms will be needed. Two Y. pestis strains (virulent and avirulent), four swab types (polyester, macrofoam, rayon, and cotton), two pre-moistening solutions, six transport media, three temperatures, two levels of organic load, and four processing methods (vortexing, sonicating, combined sonicating and vortexing, no agitation) were evaluated to determine the conditions that would yield the highest percent of cultivable Y. pestis cells after storage. The optimum pre-moistening agent/transport media combination varied with the Y. pestis strain and swab type. Directly inoculated macrofoam swabs released the highest percent of cells into solution (93.9% recovered by culture) and rayon swabs were considered the second best swab option (77.0% recovered by culture). Storage at 4°C was found to be optimum for all storage times and transport media. In a worst case scenario, where the Y. pestis strain is not known and sample processing and analyses could not occur until 72h after sampling, macrofoam swabs pre-moistened with PBS supplemented with 0.05% Triton X-100 (PBSTX), stored at 4°C in neutralizing buffer (NB) as a transport medium (PBSTX/NB) or pre-moistened with NB and stored in PBSTX as a transport medium (NB/PBSTX), then vortexed 3min in the transport medium, performed significantly better than all other conditions for macrofoam swabs, regardless of strain tested (mean 12 – 72h recovery of 85.9–105.1%, p <0.001). In the same scenario, two combinations of pre-moistening medium/transport medium were found to be optimal for rayon swabs stored at 4°C (p <0.001), then sonicated 3min in the transport medium; PBSTX/PBSTX and NB/PBSTX (mean 12–72h recovery of 83.7–110.1%). [Copyright &y& Elsevier]