I think tracking the source of drug resistance genes is not an easy task. Resistance to antibiotics is a natural phenomenon. Most of the antibiotics are fungal secondary metabolites or their derivatives. Fungi and bacteria are inhabitants of the Earth for millions of years prior humans. They're competing for resources and habitats. So, many environmental bacterial spp are intrinsically resistance to different antibiotics. The resistant phenotypes result from natural selection of members who have managed to undergo favorable mutations that confer resistance to fungal metabolites being deposited in the same niche. The same idea applies for medically important bacteria that become resistance to antibiotics gradually. Industrial wastes may contains many antimicrobial substances that induce mutations and cross resistance to antibiotics.

The natural transfer of genetic material containing resistance genes between phylogenetically related gebera/species adds an extra challenge. Of course genomic/computational analyses can determine the source species of resistance genes, yet multiple mutations within this genes may preclude source tracking.

It's a good idea to go through published literature on molecular epidemiology of resistance genes and phenotypes. The published literature regarding the development of antibiotic drug resistance is overwhelming.

When using antibiotics (veterinary or medical) we know that some species are very prevalent and adapted to a host species than to another. For example, for Salmonella enteric serovars: S. typhimurium and S. bovismorbificans are prevalent in cattle; S. Gallinarum and S. Pullorum in Chicken; S. Choleraesuis in pig; S. Paratyphi in humans.... The AMR origin may obtained via an epidemiological survey.

If we can track the origin the AMR through a genetic marker, that will be a giant leap.

Antimicrobial susceptibility testing only way to determine the AMR in human host.As like normal flora of human and animals, there's particular bacterial niche in the environmental samples based on these we can screen the source of these AMR bacteria. But we need to be reconfirmed the source by repititative antimicrobial susceptibility testing in order to assure the source of the samples.

An antimicrobial resistance could be due to several factors and it could be not depends upon so called primary targets (you will find in literature) and that's why for molecular hits to identify there's microarrays and proteomics like mechanisms are involved. A bug can throughout the drugs due to various mechanisms..Efflux pump is one of this kind.There is several mechanisms are involved and it's not restricted to primary targets. It's evolving as bacteria tries to adapt the host.

I agree with the opinions of my colleagues, regardless of the source of the resistance of bacteria, the problem of increasing resistance causes global concern at the level of public health... But in fact, there are bacterial spp. that parasitize in animal habitats and others that parasitize in humans, but there are other types in zoonoses and is transmitted between humans and animals... In general, bacteria acquire resistance genes to adapt to the selective pressure they are exposed to as a result of the misuse and abuse of antibiotics, whether in the field of animal and agricultural production or in the field of humans... And at the most, these genes may be acquired from bacteria existing in the environment or in the intestines, which are nonpathogenic through the mechanisms of genetic transfer ... In addition to the presence of genetic mobile elements such as plasmids and jumping genes (transposons), which enjoy wide freedom of movement within the bacterial populations.

Thank you so much for your opinions. Your suggestions broaden my thinking area.. @Jameel M. Abduljalil

@ Aissa Saidi

@ Dr Rajesh Sarkar

@ Manal Hadi Kanaan