Doane R M, Oliver S P, Walker R D, Shull E P
Am J Vet Res. 1987 May;48(5):749-54.
Twenty-seven quarters of 18 lactating dairy cows were inoculated intramammarily with 3.6 X 10(4) colony-forming units (CFU) of a strain of Streptococcus uberis isolated from a cow with clinical mastitis. Before quarters were inoculated, 22 were considered as naturally colonized with Corynebacterium bovis, and 5 were considered bacteriologically negative. Streptococcus uberis was isolated from all quarters within 2 days after inoculation, and all quarters developed clinical mastitis by 3 days after inoculation. Mastitis was acute, and most cows had increased rectal temperatures. The number of somatic cells increased significantly (P less than 0.05), and milk production decreased significantly. In many cows, rectal temperatures remained increased, and Str uberis was isolated from infected glands after intramammary and systemic antimicrobial treatments were given. A decreased number (110 CFU) of the same strain of Str uberis caused equally severe mastitis in 3 quarters colonized with C bovis and in 1 bacteriologically negative quarter in 2 cows. Streptococcus uberis was isolated from all inoculated quarters, and all quarters developed clinical mastitis by 2 days after inoculation. Two quarters colonized with C bovis and 2 bacteriologically negative quarters were inoculated once with 25 CFU and once with 240 CFU of a different strain of Str uberis (ATCC 27958). Streptococcus uberis was never isolated from inoculated quarters, and changes in milk yield or number of somatic cells were not observed.
将从患有临床乳腺炎的奶牛分离出的3.6×10⁴菌落形成单位（CFU）乳房链球菌菌株经乳房内接种到18头泌乳奶牛的27个乳腺区。在乳腺区接种前，22个被认为自然定殖有牛棒状杆菌，5个细菌学检测为阴性。接种后2天内从所有乳腺区分离出乳房链球菌，接种后3天所有乳腺区均发生临床乳腺炎。乳腺炎为急性，大多数奶牛直肠温度升高。体细胞数量显著增加（P<0.05），产奶量显著下降。在许多奶牛中，直肠温度持续升高，在进行乳房内和全身抗菌治疗后，仍能从感染的腺体中分离出乳房链球菌。同一菌株数量减少（110 CFU）在2头奶牛中定殖有牛棒状杆菌的3个乳腺区和1个细菌学阴性乳腺区引起同样严重的乳腺炎。接种后2天内从所有接种的乳腺区分离出乳房链球菌，所有乳腺区均发生临床乳腺炎。对2个定殖有牛棒状杆菌的乳腺区和2个细菌学阴性乳腺区分别接种25 CFU和240 CFU的另一种乳房链球菌菌株（ATCC 27958）。接种的乳腺区从未分离出乳房链球菌，也未观察到产奶量或体细胞数量的变化。
