Department of Forensic Medicine, Medical School, University of Pécs, 7624 Pécs, Hungary.
Institute of Bioanalysis, Medical School, University of Pécs, 7624 Pécs, Hungary.
Sci Justice. 2024 Mar;64(2):151-158. doi: 10.1016/j.scijus.2023.12.005. Epub 2023 Dec 22.
Good laboratory practice minimizes the biological hazard posed by potentially infectious casework samples. In certain scenarios, when the casework sample is contaminated with highly contagious pathogens, additional safety procedures such as disinfection might be advised. It was previously proven that ozone gas treatment does not hamper STR analysis, but there is no data on how the disinfection affects other steps of the forensic analysis. In this study, we aimed to assess the interference of ozone disinfection with forensic tests used to identify biological stains. A dilution series of blood, saliva, and semen samples were pipetted onto cotton fabric and let completely dry. Half of the samples were subjected to ozone treatment, while the rest served as controls. All the samples were tested with specific lateral flow immunochromatographic assays and for specific RNA markers with quantitative real-time PCR. Additionally, luminol test was carried out on blood spots, Phadebas® Amylase Test on saliva stains, and semen stains were examined with STK Lab kit and light microscope following Christmas Tree or Hematoxylin-Eosin staining. Ozone treatment had no detrimental effect on the microscopic identification of sperm cells. Undiluted blood samples were detected with luminol and immunoassay, but at higher dilution, the sensitivity of the test decreased after disinfection. The same decrease in sensitivity was observed in the detection of semen stains using STK Lab kit from STK® Sperm Tracker, and in the case of the immunoassay specific for prostate-specific antigen (PSA). Ozone treatment almost completely inhibited the enzymatic activity of amylase. The sensitivity of antibody-based detection of amylase was also greatly reduced. RNA markers showed degradation but remained detectable in blood and semen samples after incubation in the presence of ozone. In saliva, the higher Ct values of the mRNA markers were close to the detection limit, even before ozone treatment.
良好的实验室规范可最大程度降低潜在传染性检材带来的生物危害。在某些情况下，如果检材受到高传染性病原体污染，则可能需要建议额外的安全程序，例如消毒。先前已经证明，臭氧气体处理不会干扰 STR 分析，但尚无数据表明消毒如何影响法医分析的其他步骤。在这项研究中，我们旨在评估臭氧消毒对用于识别生物痕迹的法医检测的干扰。将血液、唾液和精液样本的稀释系列吸移到棉织物上，并使其完全干燥。一半的样本进行臭氧处理，其余的作为对照。所有样本均用特定的侧向流动免疫层析测定法和实时定量 PCR 进行特定的 RNA 标记物检测。此外，在血液斑上进行鲁米诺测试，在唾液斑上进行 Phadebas®淀粉酶测试，在精液斑上进行 STK Lab 试剂盒和显微镜检查，按照圣诞树或苏木精-伊红染色法进行。臭氧处理对精子细胞的显微镜鉴定没有不良影响。未稀释的血液样本可通过鲁米诺和免疫测定法检测，但在更高稀释度下，消毒后检测的灵敏度降低。使用 STK®精子追踪器的 STK Lab 试剂盒检测精液斑和针对前列腺特异性抗原 (PSA) 的免疫测定法也观察到相同的灵敏度降低。臭氧处理几乎完全抑制了淀粉酶的酶活性。基于抗体的淀粉酶检测的灵敏度也大大降低。RNA 标记物在孵育过程中存在臭氧时降解，但仍可在血液和精液样本中检测到。在唾液中，即使在臭氧处理之前，mRNA 标记物的 Ct 值也较高，接近检测限。
