Deposition of resistant bacteria and resistome through FMT in germ-free piglets

Faecal microbiota transplantation (FMT) has received considerable attention in recent years due to its remarkable efficacy in restoring a normal gut microbiome. Here, we established the groups of post-FMT recipient piglets using germ-free piglets during early life to characterize the colonization of gut microbiota composition and the enrichment of resistance gene acquisition. By metagenomic analysis, we identified 115 bacterial phyla and 2111 bacterial genera that were acquired by the FMT recipients. We found that early-life microbial colonization and the spread of resistomes in recipient piglets were age dependent. A total of 425, 425 and 358 AR genes primarily belonging to 114, 114 and 102 different types were detected in the donors, post-FMT recipients in the FMT-3D group and post-FMT recipients in the FMT-15D group respectively. Genes that encoded tetracycline, macrolide and chloramphenicol resistance proteins were the most dominant AR genes, and the results corresponded with the exposure of antibiotic consumption at farm. Bacteroides, Escherichia, Clostridium, Parabacteroides, Treponema, Lactobacillus and Enterococcus were significantly correlated with the distribution of AR genes. More importantly, the relative abundance of AR genes was positively correlated with the levels of mobile genetic elements. Our results indicate that early-life microbial colonization can persistently shape the gut microbiota and antibiotic resistome.

Dichlorodiphenyltrichloroethane usage in the former Soviet Union

DDT (Dichlorodiphenyltrichloroethane), an organochlorine pesticide (OCP), is one of 12 persistent organic pollutants (POPs) that is being proposed for elimination or control under the Stockholm Convention on POPs. This paper presents historical DDT usage in the Former Soviet Union (FSU) from different sources. Although the data from different sources do not agree with each other, the data clearly show that the usage of DDT in the FSU were intensive in the 1950s and 1960s, and the use of DDT continued until early 1990s although DDT was officially banned in 1969/1970 by the FSU government. Two estimations (high and low) are made for the historical annual DDT usage in the FSU. The total DDT usage in the FSU from 1946 and 1990 was 520 kt for the high estimation and 250 kt for the low estimation. Gridded DDT usage inventories in the FSU on a 1 degree longitude by 1 degree latitude grid system are created by using the gridded distribution of cropland density for the FSU, and show that DDT usage varied considerably across the FSU. Most DDT was applied in southern regions of the FSU where agricultural activity was greatest, such as in Moldova and Ukraine followed by the Northern Caucasus region of Russia and the Central Asian republics.