Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL 35294-2170, USA.
J Infect Dis. 2010 Jul 1;202(1):29-38. doi: 10.1086/653123.
Recently, 2 serologically and biochemically distinct subtypes-11Aalpha and 11Abeta-were discovered among serotype 11A isolates of Streptococcus pneumoniae. Sequence comparison of the capsular polysaccharide synthesis (cps) loci of the 2 subtypes identified disruption of the wcjE gene, a putative O-acetyltransferase, as the genetic hallmark of the 11Abeta phenotype. Directed disruption of wcjE in vitro in an 11Aalpha strain switched the strain to the 11Abeta phenotype, confirming the role played by the gene in the divergence between the subtypes. Furthermore, sequences from 7 11Abeta clinical strains each contained unrelated disruptive mutations in the wcjE gene, displaying an unprecedented degree of genetic heterogeneity in a pneumococcal serotype. We propose to name the 11Aalpha subtype as serotype 11A and the 11Abeta subtype as 11E, a new serotype. Our findings also suggest that the diversity of pneumococcal capsules is much greater than was previously recognized.
最近，在肺炎链球菌 11 型分离株中发现了两种血清学和生化上不同的亚型 - 11Aalpha 和 11Abeta。对这两种亚型的荚膜多糖合成 (cps) 基因座的序列比较表明，wcjE 基因的破坏，即一个假定的 O-乙酰基转移酶，是 11Abeta 表型的遗传标志。在 11Aalpha 菌株中体外定向破坏 wcjE 可将该菌株转变为 11Abeta 表型，证实了该基因在亚型分化中的作用。此外，7 株 11Abeta 临床分离株的序列在 wcjE 基因中均含有无关的破坏突变，在肺炎球菌血清型中表现出前所未有的遗传异质性。我们建议将 11Aalpha 亚型命名为血清型 11A，11Abeta 亚型命名为 11E，这是一个新的血清型。我们的研究结果还表明，肺炎球菌荚膜的多样性比以前认识到的要大得多。
