Antimicrobial susceptibility of foodborne pathogens in organic or natural production systems: an overview.

Organic and natural food production systems are increasing in popularity, at least partially because consumers perceive that these niche markets provide healthier and safer food products. One major difference between these niche markets and conventional production systems is the use of antimicrobials. Because antimicrobial agents exert selective pressures for antimicrobial resistance, relating antimicrobial susceptibility of foodborne bacteria to niche market production systems is of interest. Other differences between production systems might also influence the susceptibility of foodborne pathogens. The objective of this review is to compare the impact of food animal production systems on the antimicrobial susceptibility of common foodborne bacterial pathogens. Studies comparing the susceptibility of such pathogens were diverse in terms of geographic location, procedures, species of bacteria, and antimicrobials evaluated; thus, it was difficult to draw conclusions. The literature is highly variable in terms of production type and practices and susceptibility associations, although few studies have compared truly organic and conventional practices. When statistical associations were found between production type and minimum inhibitory concentrations or percentage of isolates resistant for a particular pathogen, the isolates from conventionally reared animals/products were more commonly resistant than the comparison group (organic, antibiotic free, etc.). Therefore, further studies are needed to better assess public health consequences of antimicrobial resistance and food animal production systems, specifically organic or natural versus conventional.