Nickerson S C, Boddie R L
Hill Farm Research Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Homer 71040.
J Dairy Sci. 1994 Sep;77(9):2526-36. doi: 10.3168/jds.S0022-0302(94)77194-0.
The influence of pre-existing Staphylococcus sp. IMI on development of new IMI after experimental challenge with Staphylococcus aureus and Streptococcus agalactiae was studied. The IMI data were analyzed from five trials in which quarters were challenged with major pathogens incident to studies of teat dip efficacy. Prior to each trial, quarter IMI status was determined, and new IMI were enumerated during challenge. Percentage of new Staph. aureus IMI in uninfected quarters was 3-fold that of quarters already infected with Staphylococcus sp. Of quarters that were initially uninfected, 13.23% acquired new Staph. aureus IMI, and 4.49% of quarters infected with Staphylococcus sp. became infected. Conversely, the percentage of new Strep. agalactiae IMI in quarters infected with Staphylococcus sp. was 1.5-fold that of uninfected quarters (8.38 vs. 5.52%). The percentage of clinical Staph. aureus IMI in uninfected quarters was higher than for quarters infected with Staphylococcus sp., but percentages of clinical Strep. agalactiae IMI were similar among IMI statuses. Geometric mean SCC prior to challenge were 87 x 10(3) for uninfected quarters and 260 x 10(3)/ml for quarters infected with Staphylococcus sp. Quarters infected with Staphylococcus sp. were less susceptible to Staph. aureus IMI, but more susceptible to Strep. agalactiae IMI.
研究了预先存在的葡萄球菌属乳房内感染（IMI）对金黄色葡萄球菌和无乳链球菌实验性攻击后新IMI发生发展的影响。IMI数据来自五项试验，在这些试验中，乳腺被与乳头浸液功效研究相关的主要病原体攻击。在每项试验之前，确定乳腺的IMI状态，并在攻击期间对新的IMI进行计数。未感染乳腺中新增金黄色葡萄球菌IMI的比例是已感染葡萄球菌属乳腺的3倍。在最初未感染的乳腺中，13.23%出现了新的金黄色葡萄球菌IMI，而感染葡萄球菌属的乳腺中有4.49%发生了感染。相反，感染葡萄球菌属的乳腺中新的无乳链球菌IMI比例是未感染乳腺的1.5倍（8.38%对5.52%）。未感染乳腺中临床金黄色葡萄球菌IMI的比例高于感染葡萄球菌属的乳腺，但临床无乳链球菌IMI的比例在不同IMI状态之间相似。攻击前未感染乳腺的几何平均体细胞计数（SCC）为87×10³，感染葡萄球菌属的乳腺为260×10³/ml。感染葡萄球菌属的乳腺对金黄色葡萄球菌IMI较不敏感，但对无乳链球菌IMI更敏感。
