Wenz J R, Barrington G M, Garry F B, McSweeney K D, Dinsmore R P, Goodell G, Callan R J
Department of Clinical Sciences, College of Veterinary Medicine, Colorado State University, Ft Collins 80523, USA.
J Am Vet Med Assoc. 2001 Oct 1;219(7):976-81. doi: 10.2460/javma.2001.219.976.
To determine the incidence of bacteremia in dairy cows with naturally occurring acute coliform mastitis (ACM) with a wide range of disease severity.
Cohort study.
144 dairy cows with ACM from 6 herds.
Cows were examined at time of identification of ACM (time 0) and classified as having mild, moderate, or severe mastitis on the basis of rectal temperature, hydration status, rumen contraction rate, and attitude. Cows were reexamined at 24 or 48 hours. Bacteriologic culturing of milk and blood (30 ml), CBC, and serum biochemical analysis were performed at each time point. Appropriate samples were obtained at a single point from herdmates without mastitis (controls) that were closely matched for lactation number and days since parturition. Blood culture results were compared among severity groups and controls by use of chi2 tests, as was outcome of an ACM episode for cows grouped by blood bacterial isolates.
Bacteria were isolated from 52 blood samples from 46 of 144 (32%) cows with ACM, which was significantly more than control cows (11/156; 7.1%). Group-1 isolates (Escherichia coli, Pasteurella multocida, Mannheimia haemolytica, Klebsiella pneumoniae, Enterobacter agglomerans, and Salmonella enterica serotype Typhimurium) were identified in 20 of 144 (14%) cows with ACM and 0 of 156 control cows. Group-1 isolates were identified in 4.3, 9.1, and 42% of cows classified as having mild, moderate, and severe ACM, respectively. Escherichia coli and K pneumoniae milk and blood isolates obtained from the same cow were of the same genotype. Bacillus spp were identified in 21 of 144 (15%) cows with ACM, which was significantly more than control cows (3/156; 1.9%). Thirty-five percent of cows with a group-1 isolate died during the mastitis episode.
Results suggest that bacteremia develops in a substantial proportion of cows with ACM. Classification of severity of disease is important for establishment of effective treatment protocols; parenteral antimicrobial treatment may be indicated in cows with ACM.
确定患有自然发生的急性大肠杆菌性乳腺炎（ACM）且疾病严重程度范围广泛的奶牛中菌血症的发生率。
队列研究。
来自6个牛群的144头患有ACM的奶牛。
在确定ACM时（时间0）对奶牛进行检查，并根据直肠温度、水合状态、瘤胃收缩率和态度将其分类为患有轻度、中度或重度乳腺炎。在24或48小时时对奶牛进行重新检查。在每个时间点进行牛奶和血液（30毫升）的细菌培养、全血细胞计数（CBC）和血清生化分析。从无乳腺炎的同群牛（对照）中在与泌乳次数和分娩后天数密切匹配的单个时间点采集适当样本。使用卡方检验比较严重程度组和对照组之间的血培养结果，以及按血液细菌分离株分组的奶牛的ACM发作结果。
从144头患有ACM的奶牛中的46头（32%）的52份血样中分离出细菌，这显著高于对照奶牛（156头中的11头；7.1%）。在144头患有ACM的奶牛中的20头（14%）和156头对照奶牛中的0头中鉴定出第1组分离株（大肠杆菌、多杀性巴氏杆菌、溶血曼氏杆菌、肺炎克雷伯菌、聚团肠杆菌和鼠伤寒沙门氏菌）。在分别分类为患有轻度、中度和重度ACM的奶牛中，第1组分离株的鉴定率分别为4.3%、9.1%和42%。从同一头奶牛获得的大肠杆菌和肺炎克雷伯菌的牛奶和血液分离株具有相同的基因型。在144头患有ACM的奶牛中的21头（15%）中鉴定出芽孢杆菌属，这显著高于对照奶牛（156头中的3头；1.9%）。有第1组分离株的奶牛中有35%在乳腺炎发作期间死亡。
结果表明，相当比例的患有ACM的奶牛会发生菌血症。疾病严重程度的分类对于制定有效的治疗方案很重要；患有ACM的奶牛可能需要进行胃肠外抗菌治疗。
