Summary. Over the years, antimicrobials have controlled many serious infectious diseases in humans and animals. The emergence and spread of antibiotic resistance are complex problems driven by numerous interconnected factors. Resistance to antibiotics is a natural biological phenomenon that results largely from the selective pressure of antibiotics use in medicine, veterinary and as growth promoters or preventive agents in food-producing animals and poultry flocks. Most resistant bacteria have mobile genetic elements (R-plasmids, transposons) that carry resistance genes. Resistant bacteria can pass on their resistance genes by vertical transfer to progeny or to other related bacteria through conjugation, transformation and transduction. Increasing prevalence of resistance to antibiotics has significant public health implications. Infections caused by resistant microbes fail to respond to treatment, resulting in prolonged illness and greater risk of death. Moreover, resistant bacteria from animals may be passed to humans via the food chain or direct animal contact, and may result in resistant infections. Several different strategies can be employed to prevent emergence and transmission of antibiotic resistance from animals to humans.

Key words: antibiotics, resistance, bacteria