Isolation of bacteriophages specific to Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa in livestock from west-central Texas

Cross-species infections of methicillin-resistant Staphylococcus aureus (MRSA) from livestock to humans have been reported. Prior studies have isolated S. aureus and associated bacteriophages from dairy cattle. This research is undertaken to isolate bacteriophages specific for Escherichia coli, S. aureus and Pseudomonas aeruginosa from 13 beef cattle, 15 sheep and 12 goat fecal samples from a ranch in Tom Green Co., Texas. Phage enrichment was carried out using E. coli American Type Culture Collection (ATCC) strain 23848, S. aureus ATCC strain 13565 and P. aeruginosa ATCC strain PA01. Phage presence was detected using lawn spotting and reconfirmed using plaque assay. Bacteriophages specific to E. coli, S. aureus and P. aeruginosa were isolated from fecal samples of sheep and goats, while only S. aureus phages were isolated from cattle feces. Statistical analysis using Fisher's exact test and nested set modeling showed significant differences in phage isolation success between livestock types.