The resistome has been used to describe to two similar yet separate concepts: All the antibiotic resistance genes in communities of both pathogenic and non-pathogenic bacteria. All of the resistance genes in an organism, how they are inherited, and how their transcription levels vary to defend against pathogens like viruses and bacteria. Discovery and Current Data The resistome was first used to describe the resistance capabilities of bacteria preventing the effectiveness of antibiotics . Although antibiotics and their accompanying antibiotic resistant genes come from natural habitats, before next-generation sequencing, most studies of antibiotic resistance had been confined to the laboratory. Increased availability of whole-genome and metagenomic next-generation sequencing techniques have revealed significant reservoirs of antibiotic resistant bacteria outside of clinical settings. Repeated testing of soil metagenomes revealed that in urban, agricultural, and forest environments, spore-forming soil bacteria showed resistance to most major antibiotics regardless of where they'd originated. In this study, they observed nearly 200 different resistance profiles among the bacteria sequenced, indicating a diverse and robust response to the antibiotics tested regardless of their bacterial target or natural or synthetic origin. Antibiotic resistant bacteria have observed through metagenomic surveys in non-clinical environments such as water treatment facilities and human microbiomes like the mouth. We now know that the antibiotic resistome exists in every environmental niche on Earth, and sequences from ancient permafrost reveal that antibiotic resistance has been around millennia before the introduction of human-synthesized antibiotics. The Comprehensive Antibiotic Research Database (CARD) was created to compile a database of resistance genes from this rapidly increasingly available bacterial genomic data. The CARD is a compilation of sequence data and identification of resistance genes in unannotated genome sequences. The database "includes bioinformatic tools that enable the identification of antibiotic resistance genes from whole- or partial-genome sequence data, including unannotated raw sequence assembly contigs”. It is a resource intended to create a better understanding of the resistome and links healthcare, environmental, agricultural datasets. Human pathogens A major question surrounding the environmental resistome is: How do pathogenic bacteria acquire antibiotic resistance genes from the environment (and vice versa)? To answer this, we need to consider the mechanisms of horizontal gene transfer (HGT) and the various opportunities for contact between environmental bacteria and human pathogens. In soil antibiotic resistant bacterial communities, resistance-conferring genes have been found on mobile genetic elements. Similarly, in an analysis of the resistome in a water treatment plant, plasmids and