Genomic Characterization of a Clinical Listeria monocytogenes ST1 Isolate Recovered from the Blood Sample of a Woman with Third Trimester Stillbirth

BACKGROUND: Listeria monocytogenes is a foodborne gram-positive bacterium which causes adverse pregnancy outcomes. Here, the genomic and phylogenetic characteristics of a L. monocytogenes isolate obtained from blood sample of a third trimester pregnant woman with stillbirth are investigated. METHODS: Whole genome DNA of L. monocytogenes ST1 was sequenced with HiSeq X Ten platform. The NCBI Prokaryotic Genome Annotation Pipeline was used to annotate the genome sequence. The sequence type (ST) and antimicrobial resistance genes were then identified. The core genome multilocus sequence typing (cgMLST) analysis with other closely related L. monocytogenes stored in the NCBI GenBank database was performed using BacWGSTdb 2.0. RESULTS: The complete genome sequence of L. monocytogenes ST1 is made up of 20 contigs totaling 2,914,725 bp, with 2886 protein-coding sequences and a GC content of 37.9%. Fosfomycin [fosX], Lincosamide antibiotic [lin] and peptide antibiotic [mprF] were discovered as antimicrobial resistance genes. In silico serogroup typing prediction revealed that L. monocytogenes ST1 belonged to serotype IVb. The closest relative of L. monocytogenes ST1, obtained from Poland in 2015, differs by only 15 cgMLST alleles. CONCLUSION: We identified a L. monocytogenes ST1 strain from blood sample of a woman with third trimester stillbirth in China. These discoveries would aid in our understanding of the genomic characteristics, mechanisms of antimicrobial resistance, and epidemiological features of this pathogen.