Institute of Biology Bucharest of Romanian Academy, Splaiul Independentei, 296, 060031, Bucharest, Romania.
Sci Rep. 2020 May 22;10(1):8497. doi: 10.1038/s41598-020-65471-6.
For the last decades, forensic microbiology became an emerging complementary tool in criminalistics. Although the insect-microbe interactions regarding pathogen transmission were extensively studied, only scarce information is available on bacterial transfer from necrophagous insects to host tissues. Our data provides the first report on the occurrence of Wohlfahrtiimonas chitiniclastica and Ignatzschineria indica in Lucilia illustris Meigen, 1826 (Diptera: Calliphoridae), and the quantitative dynamics of the two bacterial species along the insect life-stages and transfer to beef and pork host tissues using qPCR gyrase b specific primers. The content of both bacterial species increased along the insect life stages. W. chitiniclastica was detected in all developmental stages independent of the feeding substrate. I. indica was measurable with 10 gene copies ng DNA threshold starting from the third instar larvae when feeding on beef, and from the egg stage with a 10× higher representation when using the pork substrate. The transfer of bacterial species to both tissues occurred after 3 colonization days except for I. indica that was visible in beef liver only during day 5. Considering the utilization of pork tissues as human analogues, these quantitative microbial dynamics data provides first insect-specific bacterial candidates as potential colonization biomarkers in forensic investigations.
在过去的几十年中，法医微生物学已成为法庭科学中的一种新兴的辅助工具。尽管昆虫与微生物之间的相互作用在病原体传播方面得到了广泛的研究，但关于从食腐昆虫向宿主组织转移细菌的信息却很少。我们的数据首次报道了沃氏贫养单胞菌和印度伊蚊在丽蝇（双翅目：丽蝇科）中的发生情况，以及使用 qPCR 拓扑异构酶 B 特异性引物定量研究这两种细菌在昆虫生活阶段和向牛肉和猪肉宿主组织转移的动态。两种细菌的含量随着昆虫的生活阶段而增加。沃氏贫养单胞菌在所有发育阶段都可检测到，而与喂养的基质无关。当以牛肉为食时，从第三龄幼虫开始，伊蚊的数量可测量到 10 个基因拷贝 ng DNA 阈值，而当使用猪肉基质时，其代表数量要高出 10 倍。在 3 天的定植后，细菌会转移到两种组织中，但伊蚊在第 5 天才能在牛肉肝脏中看到。考虑到将猪肉组织用作人类类似物，这些定量微生物动力学数据提供了昆虫特异性的细菌候选物，可作为法医调查中潜在的定植生物标志物。
