Barkema H W, Schukken Y H, Zadoks R N
Dept. of Health Management, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PEI, Canada.
J Dairy Sci. 2006 Jun;89(6):1877-95. doi: 10.3168/jds.S0022-0302(06)72256-1.
Staphylococcus aureus is an important cause of udder infections in dairy herds. Both lactational and dry cow therapy are part of Staph. aureus control programs. Reported cure rates for Staph. aureus mastitis vary considerably. The probability of cure depends on cow, pathogen, and treatment factors. Cure rates decrease with increasing age of the cow, increasing somatic cell count, increasing duration of infection, increasing bacterial colony counts in milk before treatment, and increasing number of quarters infected. Staphylococcus aureus mastitis in hind quarters has a low cure rate compared with front quarters. Antimicrobial treatment of intramammary infections with penicillin-resistant Staph. aureus strains results in a lower cure rate for treatment with either beta-lactam or non-beta-lactam antibiotics. Other strain-specific factors may affect the probability of cure but routine diagnostic methods for use in bacteriology laboratories or veterinary practices are not yet available. The most important treatment factor affecting cure is treatment duration. Increased duration of treatment is associated with increased chance of cure. Economically, extended treatment is not always justified, even when indirect effects of treatment such as prevention of contagious transmission are taken into consideration. Usefulness of treatment trials could be improved by standardization of case definitions, consideration of host and strain factors, and sufficient statistical power. Treatment of young animals with penicillin-sensitive Staph. aureus infections is often justified based on bacteriological cure and economic outcome, whereas treatment of older animals, chronic infections, or penicillin-resistant isolates should be discouraged.
金黄色葡萄球菌是奶牛群乳房感染的重要病因。泌乳期治疗和干奶期治疗都是金黄色葡萄球菌防控计划的一部分。报道的金黄色葡萄球菌乳腺炎治愈率差异很大。治愈的可能性取决于奶牛、病原体和治疗因素。治愈率会随着奶牛年龄的增加、体细胞数的增加、感染持续时间的延长、治疗前牛奶中细菌菌落数的增加以及感染乳腺区数量的增加而降低。与前乳腺区相比，后乳腺区的金黄色葡萄球菌乳腺炎治愈率较低。用对青霉素耐药的金黄色葡萄球菌菌株进行乳房内感染的抗菌治疗，使用β-内酰胺类或非β-内酰胺类抗生素治疗的治愈率较低。其他菌株特异性因素可能会影响治愈的可能性，但细菌学实验室或兽医实践中尚未有常规诊断方法。影响治愈的最重要治疗因素是治疗持续时间。治疗持续时间延长与治愈机会增加相关。从经济角度看，即使考虑到治疗的间接效果（如预防传染性传播），延长治疗也并非总是合理的。通过病例定义标准化、考虑宿主和菌株因素以及足够的统计效力，可以提高治疗试验的有效性。基于细菌学治愈和经济结果，对感染青霉素敏感金黄色葡萄球菌的幼畜进行治疗通常是合理的，而对于老龄动物、慢性感染或对青霉素耐药的分离株则应避免治疗。
