Winter P, Schilcher F, Bagò Z, Schoder D, Egerbacher M, Baumgartner W, Wagner M
Department for Production Animals and Herd Management, Clinic for Ruminants, Vienna, Austria.
J Vet Med B Infect Dis Vet Public Health. 2004 May;51(4):176-9. doi: 10.1111/j.1439-0450.2004.00751.x.
Listeria monocytogenes was isolated from the milk of two cows and two sheep with mastitis in one quarter and one udder half. The animals were observed over a period of 2-12 months. Clinical examination of the udder, bacteriological examinations and determination of somatic cell counts of milk samples were performed monthly. All four cases suffered from a subclinical mastitis characterized by an elevated somatic cell count (0.8-10.1 x 10(6) cells/ml), a persistent shedding of Listeria and by a normal appearance of the milk. The animals did not show any systemic reaction, but all animals developed an atrophy of the infected mammary gland. Histological examinations revealed a chronic interstitial mastitis with diffuse infiltration of lymphocytes, plasma cells and macrophages. All internal organs showed no abnormalities, no Listeria could be isolated. Listeria could however be isolated from the affected mammary parenchyma and from the mammary lymph node. The results of the bacteriological examination could be confirmed by means of PCR. Using PFGE, all the isolates from the same animal were identical. Immunohistochemical examination of the ovine mammary glands achieved a very strong immunoreactivity for CD5 cells. The mode of infection and the reaction of the immune system's defense of the ovine udders are discussed.
从两头患有乳腺炎的奶牛和两只患有乳腺炎的绵羊的牛奶中分离出了单核细胞增生李斯特菌，其中两头奶牛的一个乳腺象限患病，两只绵羊的半个乳房患病。对这些动物进行了2至12个月的观察。每月对乳房进行临床检查、进行细菌学检查并测定牛奶样本的体细胞计数。所有四例均患有亚临床乳腺炎，其特征为体细胞计数升高（0.8 - 10.1×10⁶个细胞/毫升）、李斯特菌持续排出且牛奶外观正常。这些动物未表现出任何全身反应，但所有动物的感染乳腺均出现萎缩。组织学检查显示为慢性间质性乳腺炎，伴有淋巴细胞、浆细胞和巨噬细胞的弥漫性浸润。所有内脏器官均未显示异常，未分离出李斯特菌。然而，可从受影响的乳腺实质和乳腺淋巴结中分离出李斯特菌。细菌学检查结果可通过PCR得到证实。使用脉冲场凝胶电泳（PFGE），来自同一动物的所有分离株均相同。对绵羊乳腺进行免疫组织化学检查时，CD5细胞呈现出非常强的免疫反应性。文中讨论了绵羊乳房的感染方式以及免疫系统的防御反应。
