Microevolution within ST11 group Clostridioides difficile isolates through mobile genetic elements based on complete genome sequencing

• Published in: BMC genomics 2019-10, Vol.20 (1), p.796-796, Article 796
• Main Authors: Wu, Yuan, Yang, Lin, Li, Wen-Ge, Zhang, Wen Zhu, Liu, Zheng Jie, Lu, Jin-Xing
• Format: Article
• Language: English
• Subjects: Antibiotics; Capillary electrophoresis-based PCR-ribotyping; Clostridioides difficile; Clostridium; Clostridium difficile - genetics; Clostridium difficile - isolation & purification; Clustered Regularly Interspaced Short Palindromic Repeats; Complete whole genome sequencing; CRISPR spacers; DNA sequencing; DNA Transposable Elements; Drug resistance; Drug Resistance, Bacterial - genetics; Elderly; Elderly patients; Electrophoresis; Evolution (Biology); Evolution, Molecular; Genes; Genetic aspects; Genetic research; Genome, Bacterial; Genomes; Genomics; Hospital patients; Methods; Microbial drug resistance; Mobile genetic elements; tcdC deletion; Transposons; Virulence (Microbiology); Whole Genome Sequencing
• ISSN: 1471-2164; 1471-2164
• DOI: 10.1186/s12864-019-6184-1

Clade 5 Clostridioides difficile diverges significantly from the other clades and is therefore, attracting increasing attention due its great heterogeneity. In this study, we used third-generation sequencing techniques to sequence the complete whole genomes of three ST11 C. difficile isolates, RT078 and another two new ribotypes (RTs), obtained from three independent hospitalized elderly patients undergoing antibiotics treatment. Mobile genetic elements (MGEs), antibiotic-resistance, drug resistance genes, and virulent-related genes were analyzed and compared within these three isolates. Isolates 10,010 and 12,038 carried a distinct deletion in tcdA compared with isolate 21,062. Furthermore, all three isolates had identical deletions and point-mutations in tcdC, which was once thought to be a unique characteristic of RT078. Isolate 21,062 (RT078) had a unique plasmid, different numbers of transposons and genetic organization, and harboring special CRISPR spacers. All three isolates retained high-level sensitivity to 11 drugs and isolate 21,062 (RT078) carried distinct drug-resistance genes and loss of numerous flagellum-related genes. We concluded that capillary electrophoresis based PCR-ribotyping is important for confirming RT078. Furthermore, RT078 isolates displayed specific MGEs, indicating an independent evolutionary process. In the further study, we could testify these findings with more RT078 isolates of divergent origins.