Yibin Lin,1,2 Lehua Liu,1 Siyang Lu,1 Linqi Fan,1 Huaqi Hu,1 Xuanyin Wang,1 Jichao Zhu,3 Xinhua Qiang,4 Jie He,5 Hongchang Zhou,1,2,6 Shengwen Shao,1,6 Gaoming Zheng7 

1School of Medicine, Huzhou University, Huzhou, 313000, People’s Republic of China; 2Key Laboratory for Precise Prevention and Control of Major Chronic Diseases, Huzhou University, Huzhou, 31300, People’s Republic of China; 3Clinical Laboratory, Huzhou Central Hospital, Huzhou, 313000, People’s Republic of China; 4Clinical Laboratory, First People’s Hospital Affiliated to Huzhou University, Huzhou, 313000, People’s Republic of China; 5Infectious Diseases Department, First People’s Hospital Affiliated to Huzhou University, Huzhou, 313000, People’s Republic of China; 6Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, Huzhou University, Huzhou, 313000, People’s Republic of China; 7Clinical Laboratory, Affiliated Hospital of Hangzhou Normal University, Hangzhou, 310015, People’s Republic of China

Correspondence: Gaoming Zheng; Shengwen Shao, Email zheng151031@sina.com; shaoshw@zjhu.edu.cn

Background: Bacillus cereus is a common bacterium found in the environment. Some strains can cause food poisoning, and very few can cause clinically severe infections, leading to death. Here, we characterized the genome sequence of B. cereus LIN78 isolated from teeth with deep caries and compared it with those of 25 other related species.
Methods: Third-generation sequencing technology, bacteriological analyses, biochemistry, and mass spectrometry were applied to characterize the drug-resistance genes and virulence factors of B. cereus LIN78.
Results: The complete genome sequence of B. cereus Lin78 consists of 5647 genes distributed on a circular chromosome, a 393 kbp plasmid, and 928 pseudogenes (37.4% of whole-genome DNA). The LIN78 genome contains 14 sets of 16s, 23s, and 5s ribosomal RNA operons; 106 tRNA genes, one tmRNA, 12 genomic islands, six prophases, 64 repeats; 37 antibiotic-resistant genes; and 1119 putative virulence genes, including enterotoxins and cytolysins. The B. cereus LIN78 genome carries multiple copies of non-ribosomal polypeptide synthetase (NRPS) and post-translationally modified peptides (RiPPs). Phylogenetic analysis of the 26 B. cereus strains showed that B. cereus LIN78 is evolutionarily closely related to B. thuringiensis ATCC 10792 and B. cereus ATCC 14579.
Conclusion: The newly isolated B. cereus carries many virulence genes, including enterotoxins and hemolysins, similar to B. anthracis, and multiple antibiotic resistance genes. These findings suggest that the strain has a potential risk of causing disease. Our studies are vital for further exploration of the evolution of B. cereus, its pathogenic mechanisms, and the control and treatment of bacterial infections.

Keywords: bacillus cereus, whole-genome DNA sequencing, virulence factor, drug resistance gene, human teeth