Computational Systems Biology Lab

A comprehensive microbial surveillance was conducted at NASA’s Mars 2020 spacecraft assembly facility (SAF), where whole-genome sequencing (WGS) of 110 bacterial strains was performed. One isolate, designated 179-BFC-A-HS^T, exhibited less than 80% average nucleotide identity (ANI) to known species, suggesting a novel organism. This strain demonstrated high-level resistance [minimum inhibitory concentration (MIC) >256 mg/L] to third-generation cephalosporins, including ceftazidime, cefpodoxime, combination ceftazidime/avibactam, and the fourth-generation cephalosporin cefepime. The results of a comparative genomic analysis revealed that 179-BFC-A-HS^T is most closely related to Virgibacillus halophilus 5B73C^T, sharing an ANI of 78.7% and a digital DNA-DNA hybridization (dDDH) value of 23.5%, while their 16S rRNA gene sequences shared 97.7% nucleotide identity. Based on these results and the recent recognition that the genus Virgibacillus is polyphyletic, strain 179-BFC-A-HS^T is proposed as a novel species of a novel genus, Tigheibacillus jepli gen. nov., sp. nov (type strain 179-BFC-A-HS^T = DSM 115946^T = NRRL B-65666^T), and its closest neighbor, V. halophilus, is proposed to be reassigned to this genus as Tigheibacillus halophilus comb. nov. (type strain 5B73C^T = DSM 21623^T = JCM 21758^T = KCTC 13935^T). It was also necessary to reclassify its second closest neighbor Virgibacillus soli, as a member of a novel genus Paracerasibacillus, reflecting its phylogenetic position relative to the genus Cerasibacillus, for which we propose Paracerasibacillus soli comb. nov. (type strain CC-YMP-6^T = DSM 22952^T = CCM 7714^T). Within Amphibacillaceae (n = 64), P. soli exhibited 11 antibiotic resistance genes (ARG), while T. jepli encoded for 3, lacking any known β-lactamases, suggesting resistance from variant penicillin-binding proteins, disrupting cephalosporin efficacy. P. soli was highly resistant to azithromycin (MIC >64 mg/L) yet susceptible to cephalosporins and penicillins.

Original Paper: 

• G. Miliotis, P. Sengupta, A. Hameed, M. Chuvochina, F. McDonagh, A. C. Simpson, C. W. Parker, N. K. Singh, P. D. Rekha, D. Morris, K. Raman, N. C. Kyrpides, P. Hugenholtz, and K. Venkateswaran, “Novel spore-forming species exhibiting intrinsic resistance to third- and fourth-generation cephalosporins and description of Tigheibacillus jepli gen. nov., sp. nov.,” mBio, p. e00181–24, 2024.
  [bibtex]

  @article{Miliotis2024Novel,
    title = {Novel spore-forming species exhibiting intrinsic resistance to third- and fourth-generation cephalosporins and description of {Tigheibacillus} jepli gen. nov., sp. nov.},
    volume = {0},
    url = {https://journals.asm.org/doi/10.1128/mbio.00181-24},
    doi = {10.1128/mbio.00181-24},
    pmid = 38477597,
    number = {0},
    urldate = {2024-03-16},
    journal = {mBio},
    author = {Miliotis, Georgios and Sengupta, Pratyay and Hameed, Asif and Chuvochina, Maria and McDonagh, Francesca and Simpson, Anna C. and Parker, Ceth W. and Singh, Nitin K. and Rekha, Punchappady D. and Morris, Dearbháile and Raman, Karthik and Kyrpides, Nikos C. and Hugenholtz, Philip and Venkateswaran, Kasthuri},
    month = mar,
    year = {2024},
    note = {Publisher: American Society for Microbiology},
    pages = {e00181--24},
    file = {Full Text PDF:C\:\\Users\\Karthik\\Zotero\\storage\\GWM5ESQC\\Miliotis et al. - 2024 - Novel spore-forming species exhibiting intrinsic r.pdf:application/pdf},
  }