Question

describe pathways for spread off antibiotic resistance from animals to humans

Answer 1

Resistant bacteria spread to humans and other animals through poorly prepared food, close proximity and poor hygiene.

Resistant bacteria spread to the environment and food through water contaminated by faeces or through wildlife. The more we use antibiotics, the more chance bacteria have to become resistant to them.

Antibiotic use has always been associated with the development of resistance.

An antibiotic is consumed it eliminates susceptible bacterial cells, leaving behind or selecting those unusual strains that continue to grow in its presence through a Darwinian selection process.

The resistant variants then multiply becoming the predominant bacterial population and transmit their genetic resistance characteristics to offspring.

Such phenomenon can occur in saprophytic, commensal and pathogenic bacteria in humans, animals and the environment.

Food animals, fish, and vegetables are considered large reservoirs of antibiotic-resistant bacteria, as the food production chain is an ecosystem composed of different ecological niches.

where large quantities of antibiotics are used and numerous bacteria co-exist. There are two principal biological pathways involved in the evolution and development of ABR.

First, resistance can be mediated by a pre-existing phenotype in natural bacterial populations.

During the evolutionary process, bacterial cells accumulate genetic errors in existing genes (in the chromosome or plasmid) and transfer the resistant genes to progeny cells via vertical gene transfer (VGT), leading to an innate or intrinsic or natural resistance.

The second scenario, called acquired resistance, involves genetic exchanges within and between bacterial species.

It implies horizontal gene transfer (HGT) and the acquisition of new resistant genes harbored on mobile genetic elements. such as plasmids, integrons, transposons, insertion sequences, and phage-related elements.

Such genetic materials are transferred through conjugation (transfer of DNA from donor to recipient bacterial through cell-to-cell contact by pili), transformation (naked-DNA present in the environment is taken-up by the recipient cell) and transduction (a bacteriophage acts as vector and inserts DNA into recipient cell.