Genomic analysis of a multidrug-resistant Brucella anthropi strain isolated from a 4-day-old neonatal sepsis patient.

Objectives: Brucella anthropi is a Gram-negative, aerobic, motile, oxidase-positive, non-fermentative Alphaproteobacteria belonging to the family Brucellaceae. It is most commonly found in soil but is an emerging, opportunistic, nosocomial human pathogen. The objective of this study was to understand the genome features of a drug-resistant B. anthropi (SOA01) isolated from a blood culture of a 4-day-old neonate and to determine its antimicrobial resistance and pathogenic potential.

Methods: Hybrid genome assembly of B. anthropi strain SOA01 was generated using quality-trimmed short Illumina and long MinION reads. Identification and antimicrobial susceptibility profile were determined by MALDI-TOF, in silico ribosomal multilocus sequence typing (rMLST) and VITEK®2, respectively. PATRIC webserver and VFDB were used to identify antimicrobial resistance (AMR), virulence factor (VF) and transporter genes.

Results: Multidrug-resistant B. anthropi strain SOA01 has a genome of 4 975 830 bp with a G+C content of 56.29%. Several AMR, VF and transporter genes were identified in the genome. Antimicrobial susceptibility testing revealed resistance to different classes of antibiotics in strain SOA01.

Conclusion: Brucella anthropi SOA01 is a multidrug-resistant strain. Several AMR and VF genes were identified in the genome, revealing the potential threat posed by this pathogen. The genome data generated in this study are likely to be useful in better understanding its AMR mechanisms, pathogenic potential and successful adaptation from its primary habitat of soil to the human system. Since it is often misidentified as Brucella melitensis or Brucella suis, genome characterisation and detailed understanding of its biology are crucial.