Chander Yogesh, Primus Alexander, Oliveira Simone, Gebhart Connie J
Minnesota Veterinary Diagnostic Laboratory, University of Minnesota, St. Paul, MN 55108, USA.
J Vet Diagn Invest. 2012 Sep;24(5):903-10. doi: 10.1177/1040638712456975.
Since 2007, outbreaks of severe bloody diarrhea and hemorrhagic colitis have been reported in the United States and Canada. Though the primary causative agent of swine dysentery is Brachyspira hyodysenteriae, which is strongly hemolytic, the current report describes the isolation of a novel strongly hemolytic Brachyspira sp. This novel Brachyspira sp. was identified from clinical submissions at the Minnesota Veterinary Diagnostic Laboratory, and 40 of such isolates were obtained from 22 clinical submissions representing 5 states. Isolates were confirmed to be different from any known Brachyspira sp. on the basis of phylogenetic analysis of nucleotide sequences of nox and 16S ribosomal RNA (rRNA) genes. Phylogenetic analyses grouped all isolates into 2 clades (clades I and II), and grouping patterns were similar for both nox and 16S rRNA gene sequence analyses. Phenotypically, all isolates were indole and hippurate negative, and enzymatic profiling indicated 2 types of profiles, irrespective of the phylogenetic grouping, differing only in the production of β-glucosidase. The results suggest that a potentially virulent new species of Brachyspira sp., provisionally named "Brachyspira hampsonii ", is circulating among swine herds in the United States.
自2007年以来，美国和加拿大报告了严重血性腹泻和出血性结肠炎的疫情。虽然猪痢疾的主要病原体是具有强烈溶血作用的猪痢疾短螺旋体，但本报告描述了一种新型强溶血短螺旋体的分离情况。这种新型短螺旋体是从明尼苏达兽医诊断实验室的临床送检样本中鉴定出来的，从代表5个州的22份临床送检样本中获得了40株此类分离株。根据nox和16S核糖体RNA（rRNA）基因核苷酸序列的系统发育分析，确认分离株与任何已知的短螺旋体不同。系统发育分析将所有分离株分为2个进化枝（进化枝I和II），nox和16S rRNA基因序列分析的分组模式相似。在表型上，所有分离株吲哚和马尿酸盐均为阴性，酶谱分析表明有2种酶谱类型，与系统发育分组无关，仅在β-葡萄糖苷酶的产生上有所不同。结果表明，一种潜在有毒的新型短螺旋体，暂命名为“汉普森短螺旋体”，正在美国猪群中传播。
