Reference | Schwaiger2013 (10111) (Excluded)

Chicken (breed: Ross) were purchased on day one of life from one hatchery and fed for 33 (turn 1), 37 (turn 2), or 31 days (turn 3) on a conventional chicken farm in a nonexperimental setting (field study). Chicken were kept in two different houses (A and B) on the same farm in three different turns (resulting in six different flocks, two flocks in each time period). Chicken houses were nearly identically built and equipped. In case of antibiotic treatment, all antibiotics were contemporarily applied with the drinking water in both chicken houses. Sulfamethoxazole + trimethoprim was used in four flocks (turn 1 and 2 in house A and B) within the first 3-6 days of life, and not used in two flocks (turn 3 in house A and B). 40mg Sulfamethoxazole + 10mg trimethoprim/day was applied to all chicken of the first two production turns in houses A and B (four flocks) within the first week of life. In turn 3 (two flocks), sulfamethoxazole + trimethoprim was not applied. 6mg Colistinsulfate/day was used in all flocks for prevention of dysbacteriosis between days 17-25.

E. coli (n = 438) were isolated from feces taken from the floor when the chicken were in their third and fifth week of life. At each sampling time, 10 collective samples of 5 g each were taken per chicken house by one person using sterile gloves and one-time equipment.

AST Method: Broth Microdilution

Reference explicitly reports AST breakpoints: True

Reference reports using a MIC table: False