Submitted to: Conference on Rumen Function
Publication Type: Abstract Only
Publication Acceptance Date: November 16, 2000
Publication Date: N/A
Technical Abstract: Recent reports have suggested feeding of antibiotics to domestic animals may result in increased microbial resistance to antibiotics, which can have an impact on human health. We have initiated an investigation of antibiotic resistant (AR) anaerobic bacteria present in both pig feces and manure storage pits. Samples were collected from a local swine facility. AR bacteria were enumerated on complex media with and without tetracycline (Tc), erythromycin (Em), or tylosin (Ty). AR bacteria were found in all samples, and the level of resistance ranged from 4% Em resistance to 32% Ty resistance. Several Em/Ty resistant strains were also Tc resistant. Em/Ty resistant bacteria were subjected to PCR tests for the presence of a different class of erm genes. At least two strains that were ermB positive were also Tc resistant and contained a tetM gene by PCR testing and sequencing. One Em resistant strain was found to contain a 4.1-kb plasmid. .This plasmid contained an ermT gene and was capable of replicating and providing Em resistance in B. subtilis, S. gordonii, and E. coli. Total DNA preparations from each sample were tested with Em and Tc gene PCR primers and the products randomly cloned and sequenced for similarity analyses with known AR genes. The finding of a high number of identified and unidentified AR eubacteria in swine feces and manure storage pits suggests that these ecosystems may serve as reservoirs of antibiotic resistance genes.