Antimicrobial resistance in swine and chickens fed virginiamycin for growth promotion.
In a prospective controlled study, we evaluated pigs (5-month period) and chickens (11-week period) fed subtherapeutic levels of virginiamycin. A total of 13 Enterococcus faecium were isolated from 10 pigs and 17 from 8 chickens. There were 8 pulsed-field gel electrophoresis (PFGE) patterns in E. faecium isolates from pigs and 17 from chickens. Resistance to quinupristin/dalfopristin resistance occurred in 2 of 13 E. faecium from pigs and 2 of 17 E. faecium from chickens. There were no strains exhibiting high-level gentamicin (MIC> or =2000 microg/ml) or vancomycin resistance. There was no relative weight gain in animals that received virginiamycin. The mean weight increase for the pigs in the group fed virginiamycin was 107.6 lb vs. 126.4 lb in the group that did not receive virginiamycin (P=n.s.). Chickens fed virginiamycin had a mean weight increase of 1672 g vs. 1886 g in the group that did not receive virginiamycin (P=n.s.). There was no correlation between receipt of virginiamycin or weight gain and presence of quinupristin/dalfopristin-resistant strains.
Donabedian
Susan
S
Departments of Medicine and Clinical Pathology, Section of Infectious Diseases, William Beaumont Hospital, 3601 West 13 Mile Road, Royal Oak, MI 48073, USA.
Thal
Lee Ann
LA
Bozigar
Pamela
P
Zervos
Thomas
T
Hershberger
Ellie
E
Zervos
Marcus
M
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002645:Chickens / Q000254:growth & development / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D013293:Enterococcus faecalis / Q000187:drug effects / Q000302:isolation & purification; D016984:Enterococcus faecium / Q000187:drug effects / Q000302:isolation & purification; D005243:Feces / Q000382:microbiology; D005260:Female; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D011446:Prospective Studies; D013552:Swine / Q000254:growth & development / Q000382:microbiology*; D014769:Virginiamycin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D014769:Virginiamycin