Quantified sul2 determinants displayed
a similar trend to sul1. There was an interaction between treatment and time (P = 0.001) and sul2 concentrations in fecal buy LY2606368 deposits from all treatments increased in the first 42 days. DNA Damage inhibitor Levels of sul2 in AS700 and control fecal deposits on day 175 were greater than day 7 whereas in treatment A44 and T11 deposits, the concentration of sul2 decreased by day 175 and were not different than day 7. Solely the A44 treatment showed greater numbers of sul2, in comparison to the control, and only from days 0-42. Figure 3 Persistence of sulfonamide resistance genes in cattle fecal deposits under field conditions. The treatments were (N = 3; plus standard error): Control, no antimicrobial agents added to the diets of steers from which fecal deposits
originated; A44, chlortetracycline (44 ppm); AS700, chlortetracycline and sulfamethazine (each at 44 ppm); T11, tylosin (11 ppm). Erythromycin resistance genes Every erm gene quantified was affected by an interaction between treatment and time of exposure (P = 0.05, Figure 4). For erm (A), the concentrations increased in all treatments and remained greater than the day 7 values up to day 84. By day 175, the concentrations were not different from those on day 7. With the exceptions of days 98 and 112, the erm (A) in A44 fecal deposits INCB028050 order were always greater than control samples and were also greater than the concentrations in AS700 and A44 for the first 42 days. Similar to erm (A), the concentrations of erm (B) and erm (X) in control, A44, and AS700 deposits initially increased up to days 42-56 and then decreased to levels comparable to day 7. For both determinants, the concentrations decreased in T11 fecal deposits. Quantified erm (B) and erm (X) were greater in T11 deposits compared to all other treatments on day 7 and days 7-98, respectively. Reverse transcriptase In both A44 and T11 fecal deposits, the concentration of erm (T) were greater than control deposits on day 7 only. Amounts of erm (T) decreased
by day 175. This was similar to erm (F), which decreased by day 175 in all deposits except for A44 samples. Figure 4 Persistence of erythromycin resistance genes in cattle fecal depostis under field conditions. The treatments were (N = 3; plus standard error): Control, no antimicrobial agents added to the diets of steers from which fecal deposits originated; A44, chlortetracycline (44 ppm); AS700, chlortetracycline and sulfamethazine (each at 44 ppm); T11, tylosin (11 ppm). Denaturing gradient gel electrophoresis (DGGE) Representative results showing DGGE profiles from control samples are shown in Figure 5. When comparing all treatments, the DGGE profiles grouped into three main clusters (Figure 6). One cluster only consisted of day 7 DGGE profiles from A44, AS700, and T11 treatments and was least related to other DGGE profiles (42% average similarity).