Enterococci and Antibiotic Resistance

Enterococci are widely distributed in nature.Intestinal tract of humans and animals is the natural habitat of these organisms.They gain entry into raw material and foodstuffs through the water supply, food animals, or unhygienic conditions of the production and handling.Enterococci have been known to be resistant to most antibiotics used in clinical practice.Multidrug-resistant and vancomycin-resistant enterococci are commonly isolated from humans, animal sources, aquatic habitats, agricultural run-off which indicates their ability to enter the human food chain.Vancomycin-resistant enterococci are emerging as a global threat to public health.Enterococcus sp., antimicrobial resistance, transmission, animals, human, food chain Microbial resistance to antibiotics is a world-wide problem in human and veterinary medicine.It is generally accepted that the main risk factor for the increase in the antibiotic resistance is an extensive use of antibiotics.This has lead to the emergence and dissemination of resistant bacteria and resistance genes in animals and humans.In both populations antibiotics are used for therapy and prophylaxis of infectious diseases (van den Bogaard and Stobberingh 2000a).The main sector of resistance-increasing medicine usage, in regard to human health, lies within the health care sector.The antimicrobial agents used in animal care are also significant, not only in increasing the resistance in animal pathogens, but also in bacteria transmitted from animals to humans.Most studies show that not only the level of resistance of pathogenic bacteria, but also of commensal bacteria increases.Commensal bacteria constitute a reservoir of resistance genes for pathogenic bacteria.Their level of resistance is considered to be a good indicator for selection pressure by antibiotic use and for resistance problems to be expected in pathogens.Resistant commensal bacteria of food animals might contaminate, as zoonotic bacteria, meat (products) and so reach the intestinal tract of humans.Monitoring the prevalence of resistance in indicator bacteria such as faecal Escherichia coli and enterococci in different populations, animals, patients and healthy humans, makes it feasible to compare the prevalence of resistance and to detect transfer of resistant bacteria or resistance genes from animals to humans and vice versa.Only in countries that use or used avoparcin as antimicrobial growth promoter (AMPG), is vancomycin resistance common in intestinal enterococci, not only in exposed animals, but also in the human population outside hospitals.Resistance genes against antibiotics, that are or have only been used in animals i.e. nourseothricin, apramycin etc. were found soon after their introduction, not only in animal bacteria but also in the commensal flora of humans, in zoonotic pathogens such as salmonellae, but also in strictly human pathogens such as shigellae.