A comparative study on the effects of tylosin on select bacteria during continuous flow culture of mixed populations of gut microflora derived from a feral and a domestic pig.

摘要: Continuous flow cultures of feral (culture FC) and domesticated RPCF) pig gut microflora were established in steady state. Cultures continuously infused with 25 or 100 microg tylosin/mL sampled at intervals to assess effects on total culturable anaerobes, Bacteroides Enterococcus via plating agar supplemented without tylosin/mL, the latter bacterial sensitivity tylosin. Endogenous tylosin-insensitive anaerobes within cultures, while similar prior tylosin administration, responded differently during concentrations RPCF becoming enriched more than FC cultures. Tylosin-insensitive persisted increased after cessation administration whereas decreased slightly. Concentrations endogenous recovered medium near below detectable levels administered tylosin/mL. >5 log10 CFU/mL but not Populations In an exogenous-sourced E. faecium possessing resistance maintained itself only presence These results indicate that under conditions these tests, antibiotic exposure may enrich for antibiotic-insensitive bacteria populations exogenous origin ability tylosin-resistant persist is reduced absence antibiotic, likely due exclusion by native flora.