The Effect Of Trime Thoprim Combined With Antibiotics And Antiparasities Of Sulfonamides

The study investigated the effect of trimethoprim (TMP), a antimicrobial synergist of Benzylprimidine, combined withβ-lactam antibiotics, macrolides and other antibiotics against Escherichia coli, golden staphylococcus,β-Streptococcus Hemolyticus and so on. We observed the minimal inhibitory concentration (MIC) of TMP, the antibiotics alone and combined each other against the different bacterial of different concentration. We determined the synergistic effect of antibacterials and the proper ratios of TMP and antimicrobials using the fractional inhibitory concentration (FIC). We also investigated the synergy of trimethoprim (TMP) and diaveridine (DVD) with different concentration of sulfaquinoxaline (SQ) and sulfaclozine (Esb) against anticoccidial using a disease mode of chicken E.tenella in which the rate of body weight gain, the rate of survival, the value of cecum lesion and cecum E.tenella oocyst were observed. We took the anticoccidial index (ACI) as the criterion to judge the synergism effect of the antimicrobials. The results were shown as below:1. There were remarkable synergism of trimethoprim combined with ceftazidime, cefazolin, cefuroxime, amoxycillin, ampicillin and penicillin G sodium against golden staphylococcus except for cefazolin which showed additive effect. The FIC were 0.06, 0.56, 0.31, 0.315, 0.13 and 0.14 respectively.. They all showed synergism againstβ-Streptococcus Hemolyticus. The FIC were 0.14, 0.27, 0.13, 0.13, 0.38 and 0.09 respectively.2. The FIC values of Trimethoprim combined with six macrolides (Erythromycin, Azithromycin, Kitasamycin, Clarithromycin, Kitasamycin and Erythromycin Lactobionate) were 0.23, 0.17, 2, 0.5, 0.35, 0.22 against golden staphylococcus respectively. They all showed synergism except for Kitasamycin which showed no relation. The FIC values of Trimethoprim combined with the six macrolides were 0.33, 0.37, 0.31, 0.27, 0.61, 0.33 againstβ-Streptococcus Hemolyticus. They all showed synergism except for Kitasamycin which showed additive effect.3. Trimethoprim combined with penicillin G sodium and amoxicillin showed synergistic effect against Escherichia coli . It showed additive effect combined with cefazolin, Lincomycin and Oxytetracycline. It showed no synergism on metronidazole. 4. There were synergism of trimethoprim combined with Florfenicol against golden staphylococcus and Salmonella. The FIC were both 0.5. It showed additive effect against Escherichia coli and the FIC was 0.75. It showed a synergistic effect against golden staphylococcus, Escherichia coli and Salmonella when combined with Mequindox.The FIC were all 0.5.5. The ACI of TMP and DVD combined with SQ and Esb in different proportion were investigated. The ACI of 0.02% SQ and 0.06% Esb (control groups) were 151 and 162 respectively. The ACI of TMP combined with 0.01% SQ, 0.02% SQ, 0.05% SQ, 0.03% Esb, 0.06% Esb, and 0.12% Esb were 177, 181, 195, 181, 188 and 192 respectively. The ACI of DVD combined with 0.01% SQ, 0.02% SQ, 0.05% SQ, 0.03% Esb, 0.06% Esb, and 0.12% Esb were 177, 194, 194, 185, 187 and 191 respectively. The study indicated that the anticoccidial effect of SQ and Esb were improved markedly by combined with TMP or DVD. However, there was no significant difference between the two synergists of sulfanilamides.