J Wildl Dis.: Prevalence and antibiotic-resistance characteristics of Enterococcus species isolated from free-living and captive raptors in central Illinois.
Article Type: Brief article
Subject: Birds of prey (Health aspects)
Enterococcus (Health aspects)
Enterococcus (Physiological aspects)
Drug resistance in microorganisms (Research)
Authors: Marrow, J.
Whittington, J.K.
Mitchell, M.
Pub Date: 06/01/2009
Publication: Name: Journal of Avian Medicine and Surgery Publisher: Association of Avian Veterinarians Audience: Academic Format: Magazine/Journal Subject: Health Copyright: COPYRIGHT 2009 Association of Avian Veterinarians ISSN: 1082-6742
Issue: Date: June, 2009 Source Volume: 23 Source Issue: 2
Topic: Event Code: 310 Science & research
Geographic: Geographic Scope: United States Geographic Name: Illinois Geographic Code: 1USA United States; 1U3IL Illinois
Accession Number: 252006964
Full Text: Because of their predatory nature, raptor species may serve as important indicators of environmental contamination with antimicrobial-resistant bacteria. Raptors prey on small rodents and birds that have diverse habitat ranges, including urban and rural environments, and their intestinal microflora can reflect that of the animals on which they feed. Enterococcus species were selected as target organisms because they have been isolated from the avian gastrointestinal tract, can be conferred by prey items, and are capable of multiple resistance patterns. They are also a concerning source of human antimicrobial resistance. In this study, fecal cultures were obtained from May 15, 2004 to August 31, 2004, from 21 free-living raptors and 4 captive raptors. Enterococcus was isolated from 21 (84%) of the 25 birds, and 54 isolates were chosen for further study based upon unique colony morphology. The most common isolate recovered was Enterococcus faecalis (95%; 95% confidence interval, 89-100). One bird in the study was determined to have Enterococcus gallinarum. Two distinct ribotypes of E faecalis were identified, one with unique bands at 11 and 13 kb and the other with unique bands at 14 and 20 kb. Both ribotypes were found in free-living and captive birds. The Enterococcus isolates in this study demonstrated a variety of antimicrobialresistance characteristics, including almost complete resistance to amikacin, first-generation cephalosporins, spectinomycin, and sulphadimethoxime. Isolates demonstrated variable resistance to chloramphenicol, gentamicin, enrofloxacin, erythromycin, and ticarcillin. No phenotypically vancomycin-resistant E faecalis isolates were recovered from any of the raptors; 3 isolates had intermediate-level susceptibility. A significantly higher number of isolates collected from captive birds demonstrated resistance to chloramphenicol than those obtained from flee-living birds. This trend was not duplicated with any of the remaining 18 antimicrobial drugs tested. The results of this study suggest that raptors in central Illinois are coming into contact with antimicrobials, prey exposed to antimicrobials, or bacteria that are capable of transferring resistance genes. Further study is needed to determine the source of antimicrobial-resistant Enterococcus in free-living raptors, but the limited data reflecting few differences between birds with and without antimicrobial exposure suggest that treatment and release of treated wild raptors is not contributing significantly to antimicrobial resistance in the environment.

et al. 2009;45:302-313.
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