Twenty-four rams inoculated with Brucella ovis by conjunctival and preputial routes were treated with a long-acting oxytetracycline alone or in combination with dihydrostreptomycin sulfate. The combined treatment eliminated Brucella ovis from 11 of 12 (91.6%) treated rams. Only 4 of 12 (33.3%) rams treated with oxytetracycline alone were bacteriologically negative. Neither treatment resolved clinical epididymitis in 2 rams affected before treatment. Many rams had pathologic lesions in the epididymis and ampullae, which limited the efficacy of antibiotic treatment.

Oxytetracycline (OTC) pharmacokinetic values in plasma and bile were ascertained after IV administration of the drug. At 6 hours after administration of 1 mg of OTC/kg of body weight, 2.15% of the dose was found in the bile and 37.6% was found in the urine. At 2 hours after administration, the peak bile-to-plasma OTC concentration ratio was 60:1. Bioavailability of OTC was 47.6% when it was administered orally to fasted turkeys and was 9.4% when administered to fed turkeys.

Tissue specimens from muscle, liver, kidney, and injection sites were collected, and serum was obtained from 3 calves euthanatized on each of posttreatment days 5 and 22. Calves were treated with 6.7, 13.4, or 20 mg of oxytetracycline (OTC)/kg of body weight, IM, once daily for 3 days; these dosages are 1, 2, and 3 times the label dose, respectively. One control calf was euthanatized on each of posttreatment days 5 and 22. In treated male calves killed 2 days after the last injection, OTC residues were detected in all tissues and serum, using high-performance liquid chromatography. Tissues from all injection sites also were considered positive for antimicrobial residues, using swab test on premises (STOP), microbial inhibition test (MIT), and thin-layer chromatography-biautography (TLCB) test. Kidney tissues from a calf given 13.4 mg of OTC/kg and kidney and liver tissues from a calf given 20 mg of OTC/kg also were considered positive, using the MIT and TLCB. Results of the STOP only were considered positive for the liver and kidney of a calf given 20 mg of OTC/kg, but substitution of Saskatoon antibiotic medium-3 for the original medium (antibiotic medium-5) allowed the STOP to detect residues in these tissues from all treated calves. In female calves killed 19 days after the last injection, the STOP, MIT, and TLCB procedures revealed positive results for tissues from some injection sites, but revealed negative results for other tissues. High-performance liquid chromatographic analyses detected OTC in tissues from injection sites from all treated calves, in muscle and liver from a calf given 20 mg of OTC/kg, and in kidneys from calves given 13.4 or 20 mg of OTC/kg. The STOP, MIT, and TLCB procedures lacked the sensitivity of high-performance liquid chromatography for detection of OTC residues.

From July of 1997 to June of 1998, total 279 raw milk samples over wkthdarwal period after mastitis treatment from dairy farms located in the provinces of Kyonggi and Choongchung were collected to test drug residues. Each sample was tested by TTC-II test and Delvotest SP. Among the total 152 raw milk samples of cow treated by beta-lactams, 32 samples(21.2%) were positive on the Delvotest and 15 samples(9.9%) showed positive on the TTC-II test. Also, from the total 37 samples treated by sulfonamides, 5 samples(13.5%) were positive on the Delvotest and 3 samples(8.1%) showed positive on the TTC-II test. For the total 55 raw milk samples of cow treated by tetracyclines, 9 samples(16.4%) were positive on the Delvotest and 5 samples(9.1%) showed positive on the TTC-II test. In addition, from the total 35 samples treated by aminoglycosides, 7 samples(20.0%) were positive on the Delvotest and 5 samples(14.3%) showed positive on the TTC-II test. Our study shows that it is possible that drugs are to be detected by the drug residues test of and individual raw milk even over the withdrawal period after mastitis treatment and the raw milk of bulk tank.

Salmonella pullorum strain W was serially passaged on the brain heart infusion agar containing acridine orange (AO) as a concentration of 100 mcg/ml. S. pullorum A060 and S. pullorum A0150, which were subcultured 60 and 150 passages on AO media, were examined for permeability barrier function of the cell wall. A060 and A0150 were appeared to be decreased in susceptibility against hydrophobic substances such as crystal violet, chloramphenicol and rifamycin, which might be resulted from the changes of permeability barrier function of the cell

This study was carried out to treatment test for bovine mastitis by the determination of adenosine triphosphate (ATP) based on firefly bioluminescence. In the susceptibility test, cephalothin which looks the most effective were sensitive to Staphylococcus sp. (72.3 %), Micrococcus sp. (84.2 %), Streptococcus sp. (72.7 %) and Gram positive bacilli (72.7 %), Gram negative bacilli were sensitive to gentamycin (92.3 %) and Yeast-like-fungi was the most sensitive to clotrimazole, and nystatin in order. When the number of bacteria, such as Staphylococcus aureus, Candida tropicalis isolated from the mastitis milk were counted by conventional agar plating technique, and compared with the concentration of bacterial ATP, it gave a good linear relationship. The content of ATP per Staphylococcus aureus, cell was 3.1fM and Candida tropicalis showed the high level of ATP (90fM). The ATP assay was applied to the determination of minimal inhibitory concentration (MIC) of various antibiotics. When Staphylococcus aureus was incubated in the presence of different concentration of tetracycline, erythromycin, kanamycin and streptomycin sulfate and the growth was monitored by the conventional agar plating technique and ATP assay, both methods showed the same results that they were 1mcg/ml, 2mcg/ml, 6.25mcg/ml and 8mcg/ml, respectively. For the determination of susceptibility of sensitive and resistant Staphylococcus aureus isolated for the milk with mastitis to tetracycline, erythromycin, kanamycin and strepomycin sulfate, the minimum time required for the test was determined by the assay of ATP every 30 minutes during incubation of 3 hours at 37deg C. ATP concentration time curve calculated on both resistant and sensitive strains incubated 3 hours as the optimum time for the determination of susceptibilities of various antibiotics examed. The ATP concentration of each test brith (antibiotic contraining), expressed as a percentage of its own control brith (antibiotic-free) indicated values of 30 % to be indicative of each antibiotic sensitivity.

A total of 108 strains of C jejuni isolated from pigs and chickens were examined for the susceptibility to 10 antimicrobial agents and normal sera of cattle, sheep, guinea pigs and chickens. Minimal inhibitory concentration (MIC) ranges of antimicrobial agents to C jejuni isolates were = 100 micro g/ml for erythromycin, rifamycin, streptomycin and tetracycline, 50 to 100 micro g for cephalothin, = 50 micro g for ampicillin,

The capsular serogroupes and drug susceptibility of 111 isolates of Pasteurella multocida from pigs with atrophic rhinitis and pneumonic lesions were investigated. Of the 111 P multocida isolates, 42 were from lung lesions, 47 from nasal turbinate lesions and the remaining 22 from the nasal swabs. P multocida isolates were typed for capsular serogroupes A by hyaluronidase inhibition of capsule and D by acriflavine auto-agglutination. Most isolates (64.9 %) were type A, 23.4 % were type D and the remaining 11.7 % were untypable. Resistance to triple sulfa (97.3 %) was most frequent, followed by resistance to tiamulin (71.2 %), tylosin (56.8 %), streptomycin (36.9 %), and neomycin (36.0 %). The majority of the organisms were susceptible in order of prevalence to baytril (100 %), ampicillin (98.2 %), linsmycin (97.3 %), cephalothin (94.6 %), gentamycin (93.7 %), amikacin (92.3 %), tetracycline (91.9 %), trimethoprim/sulfamethoxazole (91.0 %), and kanamycin (90.1 %). No differneces in drug resistance in relation to capsular serogroupes of P multocida and the origin of lesions were noted. A high prevalence of multiple drug resistance was observed and the most common resistant patterns were Sss, Tm, Ty (12.6 %) and Sm, Sss, Tm, Ty (8.1 %) patterns