Transcriptomic profiling of Yersinia enterocolitica O:3 and O:8 reveals serotype-specific expression differences leading to largely different YstA toxin levels

The enteric pathogen Yersinia enterocolitica is a the most common gram-negative zoonotic pathogen that causes a variety of gut-associated diseases named yersiniosis ranging from enteritis, watery diarrhea, mesenteric lymphadenitis to post infectious extraintestinal sequelae such as reactive arthritis human yersiniosis. The species Y. enterocolitica comprises a diverse group of about 70 serotypes of which only 11 are harmful to humans. Among the pathogenic strains are the highly mouse-virulent 1B/O:8 strains (YeO:8). This bioserotype, in particular YeO:8 strain 8081v has been used to study the pathogenesis of Y. enterocolitica using mouse infection models. However, by far the most frequent cause of human yersiniosis in Europe and Japan (>90%) is Y. enterocolitica bioserotype O:3 (YeO:3), which is also frequently found in pigs and pork products. In this study a comparative RNA-seq-based transcriptomic approach was used to identify serotype/isolate-specific differences in the transcriptome of the isolates YeO:8 8081v and YeO:3 Y1 under infection-relevant conditions. This strategy allowed the generation of the first in-depth single-nucleotide resolution transcriptome of Y. enterocolitica, revealed major differences in the temperature- and growth phase-dependent expression profiles, and led to the discovery of changes that modulate transcripts levels of important virulence-relevant traits. Additionally a comprehensive map of transcriptional start sites for Y. enterocolitica was generated using cDNA libraries based on samples enriched for primary transcripts. RNA of Y. enterocolitica Y1 (YeO:3) and 8081v (YeO:8) from in vitro cultures