侵袭性和定植性分离株中编码三种假定B族链球菌毒力因子的基因频率。
The frequency of genes encoding three putative group B streptococcal virulence factors among invasive and colonizing isolates.
作者信息
Manning Shannon D, Ki Moran, Marrs Carl F, Kugeler Kiersten J, Borchardt Stephanie M, Baker Carol J, Foxman Betsy
机构信息
National Food Safety and Toxicology Center and Department of Pediatrics and Human Development, Michigan State University, East Lansing, Michigan, USA.
出版信息
BMC Infect Dis. 2006 Jul 17;6:116. doi: 10.1186/1471-2334-6-116.
BACKGROUND
Group B Streptococcus (GBS) causes severe infections in very young infants and invasive disease in pregnant women and adults with underlying medical conditions. GBS pathogenicity varies between and within serotypes, with considerable variation in genetic content between strains. Three proteins, Rib encoded by rib, and alpha and beta C proteins encoded by bca and bac, respectively, have been suggested as potential vaccine candidates for GBS. It is not known, however, whether these genes occur more frequently in invasive versus colonizing GBS strains.
METHODS
We screened 162 invasive and 338 colonizing GBS strains from different collections using dot blot hybridization to assess the frequency of bca, bac and rib. All strains were defined by serotyping for capsular type, and frequency differences were tested using the Chi square test.
RESULTS
Genes encoding the beta C protein (bac) and Rib (rib) occurred at similar frequencies among invasive and colonizing isolates, bac (20% vs. 23%), and rib (28% vs. 20%), while the alpha (bca) C protein was more frequently found in colonizing strains (46%) vs, invasive (29%). Invasive strains were associated with specific serotype/gene combinations.
CONCLUSION
Novel virulence factors must be identified to better understand GBS disease.
背景
B族链球菌（GBS）可导致极年幼婴儿发生严重感染，并可导致患有基础疾病的孕妇和成人发生侵袭性疾病。GBS的致病性在血清型之间和血清型内部均有所不同，菌株之间的基因含量存在相当大的差异。三种蛋白质，分别由rib编码的Rib以及由bca和bac编码的α和β C蛋白，已被提议作为GBS的潜在疫苗候选物。然而，尚不清楚这些基因在侵袭性GBS菌株与定植性GBS菌株中出现的频率是否更高。
方法
我们使用斑点印迹杂交技术对来自不同样本库的162株侵袭性GBS菌株和338株定植性GBS菌株进行筛选，以评估bca、bac和rib的频率。所有菌株均通过荚膜类型血清分型进行定义，并使用卡方检验来检测频率差异。
结果
编码β C蛋白（bac）和Rib（rib）的基因在侵袭性分离株和定植性分离株中出现的频率相似，bac分别为20%和23%，rib分别为28%和20%，而α（bca） C蛋白在定植性菌株（46%）中比在侵袭性菌株（29%）中更常见。侵袭性菌株与特定的血清型/基因组合相关。
结论
必须鉴定出新的毒力因子，以更好地了解GBS疾病。
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