Submitted to: American Association of Swine Practitioners Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 2/7/1998
Publication Date: N/A
Citation: Cray, P.J., Miller, M., Tollefson, L., Dargatz, D.A. 1998. Development of resistance in salmonella isolates of veterinary origin. American Association of Swine Practitioners Proceedings. P. 173-176. Interpretive Summary:
Technical Abstract: The emergence of resistance to antimicrobics has compromised control of many bacterial pathogens. Recently, resistance has been observed in bacteria known to cause plague as well as Staphylococcus aureus, a common pathogen of wound and blood infection. Additionally, multiple resistance has also emerged among many bacterial strains including Salmonella species. A penta-resistant strain (Salmonella typhimurium DT104) in which the resistance genes have been chromosomally integrated is proving to be particularly problematic resulting in increased morbidity and mortality in both animals and humans. The main reservoir appears to be cattle although it has been recovered from a variety of animal species. The development of antimicrobial resistance has emerged as a global problem. Expert scientific groups such as the Institute of Medicine, the American Society for Microbiology and the World Health Organization expressed apprehension about the national and global increase in antibiotic resistance and the complex issues surrounding the increase in the community and institutional settings. The development of resistant human pathogenic bacteria results from direct use of antimicrobial agents in humans and acquisition of resistant organisms or resistance factors from animal and environmental bacteria. Recovery of antibiotic resistant bacteria occurs more often in urban that rural settings implicating contaminated food products as the likely vehicle rather than the actual animals. Although food borne illness transmitted through foods contaminated by infected human food handlers must be considered along with animal sources, this mode of transmission has historically been of less importance. Person-to-person spread of foodborne pathogens is also possible, although food borne outbreaks are generally contained with few or no secondary cases except in institutions; transmission by this route is more common with E. coli and Shigella infections. Interestingly, the resistance patterns of intestinal flora from meat eaters does not differ when compared to vegetarians. The intestinal flora of animals that have been treated or prophylaxed with antimicrobial agents can serve as a reservoir of resistance factors. Use of antibiotics in animals can result in a human health hazard in a number of ways: if antibiotic-resistant bacteria pathogenic to humans are selected and food is contaminated during slaughter or food preparation, the bacteria may cause an infection that requires treatment and therapy is compromised; if antibiotic resistant bacteria pathogenic to humans are selected in the animal and food is contaminated, the bacteria may transfer the resistance to other bacteria in the human gut; or if antibiotics remain as residues in animal products, the residues may allow the selection of antibiotic-resistant bacteria in the consumer.