Submitted to: Emerging Infectious Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2002
Publication Date: 3/24/2002
Citation: Jackson, C.R., Cray, P.J., Barrett, J.B., Ladely, S.R. 2002. Prevalence of aminoglycoside resistance among enterococci isolated from poultry and swine. Emerging Infectious Diseases. Board 18. P. 74.
Technical Abstract: In this study, the prevalence of resistance to three aminoglycosides (gentamicin, kanamycin, and streptomycin) in enterococci isolated from poultry and swine was examined. One hundred and sixty-two enterococci from poultry and 444 enterococci from swine were isolated and speciated. The predominant species identified were Enterococcus faecium (n=105), followed by Enterococcus faecalis (n=40), and Enterococcus durans (n=8) from poultry and Enterococcus durans (n=175), followed by Enterococcus faecalis (n=120), and Enterococcus faecium (n=106) from swine. Approximately 74% of the poultry enterococci and 60% of the swine enterococci were resistant to at least one aminoglycoside. Using PCR, the isolates were also examined for the presence of 12 aminoglycoside resistance genes (ant(6)-Ia, ant(6)-Ib, ant(9)-Ia, ant(9)-Ib, ant(4')-Ia, ant(3")-Ia, aph(3')-IIIa, aph(2")-Ib, aph(2")-Ic, aph(2")-Id, aac(6')-Ie- aph(2")-Ia, and aac(6')-Ii). Eight of these resistance genes were identified in the isolates, most frequently aac(6')-Ii and ant(6)-Ia from E. faecium from both poultry and swine samples. E. faecium also contained the highest combination of resistance genes for both poultry and swine. Thirty-seven percent of E. faecium from poultry contained aac(6')-Ii-ant(6)-Ia-aph(2")-Ic while 21% from swine contained aac(6')- Ii-ant(6)-Ia-aph(3")-IIIa. Seven isolates exhibiting high-level resistance to all three antimicrobials (MIC >/= 1024 mg/ml) were negative for all genes tested. These data suggest that enterococci from animal sources contain diverse and potentially unidentified aminoglycoside resistance genes.