Owens W E, Xiang Z Y, Ray C H, Nickerson S C
Louisiana State University Agricultural Center, Homer 71040.
J Dairy Sci. 1990 Dec;73(12):3449-56. doi: 10.3168/jds.S0022-0302(90)79043-1.
Twenty-five Staphylococcus aureus strains isolated from bovine mastitis were tested for their susceptibility to ceftiofur. Zone diameter for 30 micrograms disks averaged 39 mm, and minimum inhibitory concentrations ranged from .5 to 1 microgram/ml. Tissue and milk concentrations were determined from biopsy and quarter milk samples collected from eight cows treated with either intramammary infusion of 100 or 200 mg of ceftiofur, one or two intramuscular injections of 500 mg of ceftiofur, or combination therapy of intramammary infusion coupled with intramuscular injection. Three additional cows received two intramammary infusions of 200 mg of cephapirin at 24-h intervals. Intramuscular injections of ceftiofur resulted in tissue and milk concentrations below detectable limits. Staphylococcus aureus was not eliminated from infected mammary glands by infusion of 100 mg of ceftiofur or by injection of 500 mg of ceftiofur by 48 h after treatment. Combination therapy of 100 mg of ceftiofur infused and 500 mg injected reduced S. aureus numbers in milk and tissue markedly, as did infusion of 200 mg of ceftiofur. Cows receiving intramammary infusion of 200 mg of ceftiofur (two doses at 24-h intervals) had highest concentrations in milk (450 micrograms/ml at 4 and 6 h) and in tissue (.08 microgram/mg at 30 h). These concentrations are similar to those obtained with two 200-mg doses of cephapirin at 24-h intervals. Histologic analysis of mammary parenchymal tissues showed that combination therapy resulted in higher percentages of alveolar luminal area and lower percentages of interalveolar stroma compared with infusion or injection alone. Histology of quarters receiving combination therapy was not different from that of quarters receiving cephapirin infusion alone.
对从牛乳腺炎中分离出的25株金黄色葡萄球菌进行了头孢噻呋敏感性测试。30微克纸片的抑菌圈直径平均为39毫米，最低抑菌浓度范围为0.5至1微克/毫升。从八头接受乳房内注入100或200毫克头孢噻呋、一或两次肌肉注射500毫克头孢噻呋或乳房内注入与肌肉注射联合治疗的奶牛所采集的活检组织和乳区乳样中测定组织和乳汁浓度。另外三头奶牛每隔24小时接受两次乳房内注入200毫克头孢匹林。肌肉注射头孢噻呋导致组织和乳汁浓度低于检测限。在治疗后48小时，注入100毫克头孢噻呋或注射500毫克头孢噻呋未能清除感染乳腺中的金黄色葡萄球菌。注入100毫克头孢噻呋并注射500毫克的联合治疗以及注入200毫克头孢噻呋均显著降低了乳汁和组织中的金黄色葡萄球菌数量。接受乳房内注入200毫克头孢噻呋（每隔24小时两次）的奶牛乳汁（4小时和6小时时为450微克/毫升）和组织（30小时时为0.08微克/毫克）中的浓度最高。这些浓度与每隔24小时两次注入200毫克头孢匹林所获得的浓度相似。乳腺实质组织的组织学分析表明，与单独注入或注射相比，联合治疗导致肺泡腔面积百分比更高，肺泡间基质百分比更低。接受联合治疗的乳区组织学与仅接受头孢匹林注入的乳区无异。
