Antimicrobial resistance (AMR) is a major threat to global health. Understanding the emergence, evolution, and transmission of individual antibiotic resistance genes (ARGs) is essential to develop sustainable strategies combatting this threat. Here, we use metagenomic sequencing to analyse ARGs in 757 sewage samples from 243 cities in 101 countries, collected from 2016 to 2019. We find regional patterns in resistomes, and these differ between subsets corresponding to drug classes and are partly driven by taxonomic variation. The genetic environments of 49 common ARGs are highly diverse, with most common ARGs carried by multiple distinct genomic contexts globally and sometimes on plasmids. Analysis of flanking sequence revealed ARG-specific patterns of dispersal limitation and global transmission. Our data furthermore suggest certain geographies are more prone to transmission events and should receive additional attention.

In March 2020, several international organizations started making recommendations regarding the need for prompt coronavirus-based diagnosis in order to prevent its spread among the world's population. The most widely used test for confirmation of COVID-19 is real-time PCR (RT-PCR). This technique uses plastic supplies in its procedures, which are 100% disposable to avoid cross-contamination and biological risks. The scientific community has become increasingly worried because of the environmental impacts associated with the current COVID-19 pandemic, such as medical plastic residues. We classified and estimated the amount of plastic residues generated as a consequence of COVID-19 diagnostic tests and analyzed the relationships of the plastics generated with number of confirmed cases, population size, and gross domestic product in each country. We evidenced that the RT-PCR generates 37.27 g of plastic residues per sample. All patients COVID-19 tested with RT-PCR have generated 15,439.59 tons of plastic residue worldwide, until August 2020. The plastic residues generated by the COVID-19 tests have no relation with size population or gross domestic product of the countries. There is also no relationship between the plastic residues generated by the COVID-19 tests and the confirmed cases. About 97% of the plastic residues from diagnostic tests for coronavirus are incinerated due to their hazardous nature to humans, but toxic chemicals are released into the environment during the process. In the short term, there is a need to reduce plastic waste and improve controls of gas emissions from incineration plants in countries where there is a deficit. In the long term, biodegradable biomedical manufacturing that are free of releasing toxic chemicals when they are incinerated, must be considered.

The opportunistic human pathogen, Pseudomonas aeruginosa, is a major cause of infections in chronic wounds, burns and the lungs of cystic fibrosis patients. The P. aeruginosa genome encodes at least three proteins exhibiting the characteristic three domain structure of autotransporters, but much remains to be understood about the functions of these three proteins and their role in pathogenicity. Autotransporters are the largest family of secreted proteins in Gram-negative bacteria, and those characterised are virulence factors. Here, we demonstrate that the PA0328 autotransporter is a cell-surface tethered, arginine-specific aminopeptidase, and have defined its active site by site directed mutagenesis. Hence, we have assigned PA0328 with the name AaaA, for arginine-specific autotransporter of P. aeruginosa. We show that AaaA provides a fitness advantage in environments where the sole source of nitrogen is peptides with an aminoterminal arginine, and that this could be important for establishing an infection, as the lack of AaaA led to attenuation in a mouse chronic wound infection which correlated with lower levels of the cytokines TNFα, IL-1α, KC and COX-2. Consequently AaaA is an important virulence factor playing a significant role in the successful establishment of P. aeruginosa infections.

resistance against antimicrobials that are critical for human and veterinary medicine, representing a major threat for public health. Additionally, these strains could have a competitive advantage in the presence of antimicrobial selective pressure, leading to an increase in food contamination. This study highlights the need for coordinated local and global actions regarding the use of antimicrobials in animal food production.

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