Glossary

Antimicrobial (agent)

Antibiotic

Co-resistance

Defined as a natural or synthetic substance that kills or inhibits the growth of micro-organisms such as bacteria (anti-bacterial), fungi (anti-fungal) and virus (anti-viral)

An antimicrobial compound produced by an organism.

Two or more genetically linked resistance genes. Genes responsible for two or more resistances can be located next to each other on one mobile genetic element therefore are likely to be subject to combined transmission by HGT.

Co-selection

The selection of multiple AMR genes when one of these genes is selected e.g. the integron is a cassette of resistance genes that are under the control of a single promotor. As a result, the genes are expressed in a coordinate manner. Since they are a form of transposon( transposable element) they can become a part of the bacterial chromosome or plasmid and can then be transmitted among different strains.

Cross-resistance

A single resistance mechanism confers resistance to an entire class of antimicrobial agents for example antibiotics and heavy metals.

Exaptation

Exogenous micro-organisms

The process by which a traits/features acquire functions for which they were not originally selected

Micro-organisms introduced to closed biological systems from the external world. Such systems can be aquatic and terrestrial systems. This class of bacteria are found in the environment but can survive in our bodies – typically called disease causing micro-organisms.

Horizontal Gene Transfer (HGT) The movement of genetic material between unicellular and/or multicellular organisms other than by the transmission of DNA from parent to offspring.

Integrons

Genetic elements capable of acquiring and exchanging DNA fragments named gene cassettes. Class 1 integrons are assumed to catalyse co-selection as frequently contain gene cassettes that mediate resistance to antimicrobials and are frequently found in contaminated environments.

MCC minimum heavy metal concentration which correlates with a detection of increased resistance specified as the minimum co-selective concentration (MCC) of a metal. If the environmental metal concentrations exceed the https://mottmac-my.sharepoint.com/personal/bryony_osbourn_mottmac_com/Documents/AMR/Natural corresponding MCC value then they are considered to be driving the dissemination of AMR. https://mottmac-my.sharepoint.com/personal/bryony_osbourn_mottmac_com/Documents/AMR/Natural

MIC antimicrobial concentrations needed to inhibit microbial growth. If the MIC is greater than an epidemiological cut off value then the strain is defined as being antimicrobial resistant.