Antimicrobial resistance of Enterococcus from organic and conventional retail poultry in Davidson County, Tennessee

Ashlee Nicole Brown, Tennessee State University


Antimicrobial resistance in human pathogens is an escalating public health problem in the United States. Enterococci have emerged as an important cause of nosocomial infection. The use of antimicrobials in poultry production results in the presence of drug resistant bacteria. This work aimed to isolate and characterize Enterococci from raw chicken purchased from various local retail stores in Davidson County, Tennessee. Three hundred and sixteen samples consisting of organic and conventional chicken were analyzed for Enterococci by using conventional methods, API 20 Strep test System, and polymerase chain reaction. The Kirby-Bauer disk diffusion test was used to determine antibiotic resistance of Enterococcus isolated from raw chicken. The majority of the Enterococcus isolates were susceptible to amoxicillin/clavulanic acid, cefaclor, and erythromycin. Our results indicate that 94.8% (n = 109) of the isolates tested displayed multidrug resistance to three or more antibiotics. Resistance was most frequently observed to penicillin and streptomycin in conventional ground breast, with 100% resistance. In organic ground chicken breast, resistance levels were found for the antibiotics as follows: streptomycin (90%), cefoxitin (86.7%), penicillin (83.3%), amikacin (83.3%), kanamycin (76.7%). With few exceptions, resistance against the different categories of antibiotics was more prevalent in strains from conventional chicken than in organic chicken. In organic poultry, drumsticks showed the least resistance to ampicillin (4.1%) while breast were least resistant to amoxicillin/clavulanic and ampicillin (4.6%). Resistance to antibiotics was detected in conventional and organic chicken as 46.02% and 31.03%, respectively. Results from this study suggest retail meats, both conventional and organic, are significant sources of antibiotic-resistant Enterococci. Thus, the presence of antibiotic resistant Enterococci on chicken meat retailed in markets may render a significant public health risk for humans. Therefore, there is need to educate consumers on safe food handling practices.

Subject Area

Food Science|Agriculture

Recommended Citation

Ashlee Nicole Brown, "Antimicrobial resistance of Enterococcus from organic and conventional retail poultry in Davidson County, Tennessee" (2012). ETD Collection for Tennessee State University. Paper AAI1533487.