Molecular heterogeneity of Ehrlichia chaffeensis isolates determined by sequence analysis of the 28-kilodalton outer membrane protein genes and other regions of the genome.

ABSTRACT: Ehrlichia chaffeensis, a tick-transmitted rickettsial agent, is responsible for human monocytic ehrlichiosis (HME). In this study, we genetically mapped 10 isolates obtained from HME patients. Sequence analysis of the 28-kDa outer membrane protein (OMP) multigene locus spanning 6 of the 22 tandemly arranged genes identified three distinct genetic groups with shared homology among isolates within each group. Isolates in Groups I and III contained six genes each, while Group II isolates had a gene deletion. There were two regions on the locus where novel gene deletion or insertion mutations occurred, resulting in the net loss of one gene in Group II isolates. Numerous nucleotide differences among genes in isolates of each group also were detected. The shared homology among isolates in each g

SUBMITTER: Cheng C 

PROVIDER: S-EPMC143425 | biostudies-literature | 2003 Jan

REPOSITORIES: biostudies-literature