Haftu Rgbe, Taddele Habtamu, Gugsa Getachew, Kalayou Shewit
School of Veterinary Medicine, Addis Ababa University, Debre Zeit, Ethiopia.
Trop Anim Health Prod. 2012 Oct;44(7):1765-71. doi: 10.1007/s11250-012-0135-z. Epub 2012 Apr 4.
The study was undertaken to determine the prevalence of bovine mastitis, isolate mastitis causing bacteria, assess the association of some risk factors, and determine the antibiotic resistance pattern of bacterial isolates in cows in large-scale dairy farms of Northern Ethiopia. A total of 305 lactating and nonlactating cows were included in the present study. The overall prevalence of clinical and subclinical mastitis was 3.6 and 33.8 %, respectively. The quarter level prevalence was 15.4 %; from which, 11.9 and 1.1 % were subclinical form and blind teat, respectively, while the remaining 2.4 % were of clinical form. Staphylococcus aureus accounted for 36 % of the isolates followed by Escherichia coli (27.3 %). Risk factors including age (p < 0.001), parity (p < 0.001), and lactation stage (p = 0.02) showed significant association with the occurrence of mastitis. Higher prevalence was observed in both groups of older cows (i.e., 6-9 years (odds ratio (OR) = 4.65, 95 % confidence interval (CI) = 2.74-7.89) and >9 years (OR = 3.63, 95 % CI = 1.42-9.25)), cows with four to seven calves (OR = 3.39, 95 % CI = 2.06-5.60), and cows in late lactation stage (OR = 3.79, 95 % CI = 1.64-8.75). In multivariable logistic regression analysis, age (p = 0.005) and lactation stage (p = 0.027) showed statistically significant association with the occurrence of mastitis. The antimicrobial susceptibility pattern showed high susceptibility of S. aureus to nalidixic acid (82.4 %) followed by chloramphenicol (58.8 %); however, these species were resistant to the rest of the antimicrobials tested. Highest resistance was observed against clindamycin and ampicillin. Coliform bacteria (E. coli and Klebsiella pneumoniae) showed resistance to most of the antimicrobials used. Detailed investigation is needed to identify the interplay of managemental and environmental risk factors to design appropriate control measures.
本研究旨在确定埃塞俄比亚北部大型奶牛场奶牛乳房炎的患病率，分离引起乳房炎的细菌，评估一些风险因素的关联，并确定细菌分离株的抗生素耐药模式。本研究共纳入305头泌乳和非泌乳奶牛。临床型和亚临床型乳房炎的总体患病率分别为3.6%和33.8%。乳房四分位患病率为15.4%；其中，亚临床型和盲乳头分别占11.9%和1.1%，其余2.4%为临床型。金黄色葡萄球菌占分离株的36%，其次是大肠杆菌（27.3%）。年龄（p<0.001）、胎次（p<0.001）和泌乳阶段（p = 0.02）等风险因素与乳房炎的发生呈显著关联。在两组老龄奶牛（即6 - 9岁（优势比（OR）= 4.65，95%置信区间（CI）= 2.74 - 7.89）和>9岁（OR = 3.63，95% CI = 1.42 - 9.25））、产犊4至7头的奶牛（OR = 3.39，95% CI = 2.06 - 5.60）以及泌乳后期的奶牛（OR = 3.79，95% CI = 1.64 - 8.75）中观察到较高的患病率。在多变量逻辑回归分析中，年龄（p = 0.005）和泌乳阶段（p = 0.027）与乳房炎的发生呈统计学显著关联。抗菌药敏模式显示，金黄色葡萄球菌对萘啶酸的敏感性较高（82.4%），其次是氯霉素（58.8%）；然而，这些菌株对其余测试的抗菌药物耐药。观察到对克林霉素和氨苄西林的耐药性最高。大肠菌群（大肠杆菌和肺炎克雷伯菌）对大多数使用的抗菌药物耐药。需要进行详细调查以确定管理和环境风险因素之间的相互作用，从而设计适当的控制措施。
