Genomic characterization and assessment of the virulence of the novel Paenibacillus sp. VT-400, a potentially pathogenic bacterium

Genomic characterization and assessment of the virulence and antibiotic resistance of the novel species Paenibacillus sp. strain VT-400, a potentially  pathogenic bacterium in the oral cavity of patients with hematological  malignancies

Gut pathogens (2016)

Publication Type Journal Article
Authors George Tetz
Victor Tetz
Maria Vecherkovskaya
Abstract Background

Paenibacillus sp. strain VT-400, a novel spore-forming bacterium, was isolated from patients with hematological malignancies.


Paenibacillus sp. strain VT-400 was isolated from the saliva of four children with acute lymphoblastic leukemia. The genome was annotated using RAST and the NCBI Prokaryotic Genome Annotation Pipeline to characterize features of antibiotic resistance and virulence factors. Susceptibility to antibiotics was determined by the Kirby–Bauer disc diffusion method. We used a mouse model of pneumonia to study virulence in vivo. Mice were challenged with 7.5 log10–9.5 log10 CFU, and survival was monitored over 7 days. Bacterial load was measured in the lungs and spleen of surviving mice 48 h post-infection to reveal bacterial invasion and dissemination.


Whole-genome sequencing revealed a large number of virulence factors such as hemolysin D and CD4+ T cell-stimulating antigen. Furthermore, the strain harbors numerous antibiotic resistance genes, including small multidrug resistance proteins, which have never been previously found in the Paenibacillus genus. We then compared the presence of antibiotic resistance genes against results from antibiotic susceptibility testing. Paenibacillus sp. strain VT-400 was found to be resistant to macrolides such as erythromycin and azithromycin, as well as to chloramphenicol and trimethoprim–sulphamethoxazole. Finally, the isolate caused mortality in mice infected with ≥8.5 log10 CFU.


Based on our results and on the available literature, there is yet no strong evidence that shows Paenibacillus species as an opportunistic pathogen in immunocompromised patients. However, the presence of spore-forming bacteria with virulence and antibiotic resistance genes in such patients warrants special attention because infections caused by spore-forming bacteria are poorly treatable.

Year of
Journal Gut Pathogens
DOI 10.1186/s13099-016-0089-1