Hassan A A, Abdulmawjood A, Yildirim A O, Fink K, Lämmler C, Schlenstedt R
Institut für Tierärztliche Nahrungsmittelkunde, Bakteriologie und Hygiene der Milch, Justus-Liebig-Universität Giessen, Germany.
Can J Microbiol. 2000 Oct;46(10):946-51.
In the present study, the CAMP-factor (cfb) gene of streptococci of serological group B (Streptococcus agalactiae) and the CAMP-factor (cfu) gene of S. uberis could be amplified by polymerase chain reaction. A cfb specific amplicon could be observed for all 128 phenotypically CAMP-positive S. agalactiae, for the phenotypically CAMP-negative S. agalactiae strain 74-360, and for 2 S. difficile reference strains. A cfu specific amplicon could be observed for all 7 phenotypically CAMP-positive S. uberis. Four S. agalactiae strains isolated from 4 cows with mastitis appeared to be phenotypically CAMP-negative and negative in the cfb gene PCR. The CAMP-positive and CAMP-negative isolates, including both S. difficile, could be identified as S. agalactiae by amplification of a S. agalactiae specific part of the V2 region of the 16S rRNA and a species-specific part of the 16S-23S rRNA intergenic spacer region. Amplification of an internal fragment of the cfb gene with a reduced annealing temperature yielded positive reactions not only for CAMP-positive S. agalactiae, but also for phenotypically CAMP-positive S. pyogenes (n = 4), S. canis (n = 28), and S. uberis (n = 7), indicating a close relation of the CAMP genes of these 4 species. The relation could be further demonstrated by sequencing the internal fragment of the CAMP-factor (cfg) gene of S. canis and comparing the sequence with those of S. agalactiae, S. pyogenes, and S. uberis.
在本研究中，B 族血清群链球菌（无乳链球菌）的 CAMP 因子（cfb）基因和乳房链球菌的 CAMP 因子（cfu）基因可通过聚合酶链反应进行扩增。对于所有 128 株表型 CAMP 阳性的无乳链球菌、表型 CAMP 阴性的无乳链球菌菌株 74 - 360 以及 2 株艰难梭菌参考菌株，均可观察到 cfb 特异性扩增产物。对于所有 7 株表型 CAMP 阳性的乳房链球菌，均可观察到 cfu 特异性扩增产物。从 4 头患乳腺炎的奶牛分离出的 4 株无乳链球菌菌株，在表型上为 CAMP 阴性，且在 cfb 基因 PCR 中呈阴性。通过扩增 16S rRNA 的 V2 区域的无乳链球菌特异性部分以及 16S - 23S rRNA 基因间隔区的物种特异性部分，包括两株艰难梭菌在内的 CAMP 阳性和 CAMP 阴性分离株均可被鉴定为无乳链球菌。降低退火温度对 cfb 基因内部片段进行扩增，不仅对 CAMP 阳性的无乳链球菌产生阳性反应，对表型 CAMP 阳性的化脓性链球菌（n = 4）、犬链球菌（n = 28）和乳房链球菌（n = 7）也产生阳性反应，这表明这 4 个物种的 CAMP 基因关系密切。通过对犬链球菌 CAMP 因子（cfg）基因内部片段进行测序，并将序列与无乳链球菌、化脓性链球菌和乳房链球菌的序列进行比较，可进一步证明这种关系。
