Author
BEHM, SANDY - IOWA STATE UNIVERSITY | |
PEREIRA, SONIA - IOWA STATE UNIVERSITY | |
Wesley, Irene | |
Bouchard, Christopher | |
ZHANG, QIJING - IOWA STATE UNIVERSITY |
Submitted to: Research Workers in Animal Diseases Conference Proceedings
Publication Type: Abstract Only Publication Acceptance Date: 9/9/2004 Publication Date: 11/14/2004 Citation: Behm, S., Pereira, S., Wesley, I.V., Bouchard, C.T., Zhang, Q. 2004. Antibiotic resistance profiles of Campylobacter strains isolated from swine [abstract]. Conference of Research Workers in Animal Diseases. p. 91. Interpretive Summary: Technical Abstract: Campylobacter is a microaerophilic, thermophilic, gram-negative rod present among the normal intestinal flora of ruminants, poultry, and swine. Although it is nonpathogenic commensal of livestock, it causes gastroenteritis in humans. Transmission is most commonly associated with consumption of contaminated undercooked meat, poultry, water, and unpasteurized milk. Human Campylobacter infections are commonly treated with quinolone or macrolide antibiotics. However, the observed rise in the number of Campylobacter resistant to quinolone and macrolide antibiotics may be related to the use of antibiotics in animal agriculture. For example, swine feed is supplemented with the macrolide tylosin to promote growth while the macrolide erythromycin is used to treat Campylobacter infections in humans. This study focuses on the possible link between the use of tylosin in swine production and the occurrence of erythromycin resistant C. coli isolated from such swine. C. coli strains (n = 152) isolated from swine farms in the Midwest were tested by agar dilution antibiotic susceptibility method for ciprofloxacin, doxycyline, erythromycin, gentamicin, and meropenem. Initial trials (n = 106 isolates) indicated resistance to ciprofloxacin (2.8%), doxycycline (37.7%), and erythromycin (44.3%), but not to gentamicin (0.0%). In a limited test (n = 34 isolates), none were resistant to meropenem. The high resistance rate for erythromycin is consistent with the fact that macrolide antibiotics are used for swine production. PCR was then used to amplify the 23S ribosomal DNA on selected resistant and sensitive strains (n = XXX) to determine the genetic mechanisms responsible for erythromycin resistance. Sequencing results indicated that the resistant isolates have (or lack) the mutation in the 23S RNA gene, specific locus which encodes macrolide antibiotic resistance in Campylobacter. Together these findings indicate that swine Campylobacter isolates are highly resistant to erythromycin, which may be associated with the use of this class of antibiotics as growth promotants in swine production. |