Identification and Characterization of a Novel Genomic Island Harboring Cadmium and Arsenic Resistance Genes in Listeria welshimeri

• Published in: Biomolecules (Basel, Switzerland) Switzerland), 2021-04, Vol.11 (4), p.560
• Main Authors: Lee, Sangmi, Parsons, Cameron, Chen, Yi, Hanafy, Zahra, Brown, Eric, Kathariou, Sophia
• Format: Article
• Language: English
• Subjects: Aquatic environment; Arsenic; Arsenic - toxicity; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Cadmium; Cadmium - toxicity; Cloning; Cystathionine b-lyase; Drug Resistance, Bacterial; Foodborne pathogens; Genetic diversity; Genomes; Genomic Islands; Genomics; heavy metal resistance; Heavy metals; LGI2-3; Listeria; Listeria - drug effects; Listeria - genetics; Listeria genomic island 2 (LGI2); Listeria monocytogenes; Listeria welshimeri; Listeriosis; Lyases - genetics; Lyases - metabolism; Minimum inhibitory concentration; Nucleotide sequence; Sequence analysis; Software
• ISSN: 2218-273X; 2218-273X
• DOI: 10.3390/biom11040560

the bacterial foodborne pathogen responsible for the severe disease listeriosis, frequently exhibits heavy metal resistance. Concurrent resistance to cadmium and arsenic in is strongly associated with the 35-kb chromosomal island LGI2. LGI2 has been encountered repeatedly among serotype 4b hypervirulent clones but, surprisingly, not among non-pathogenic spp. Here we describe a novel LGI2 variant, LGI2-3, in two strains from an urban aquatic environment. Whole genome sequence analysis revealed that the genomes were closely related except for one prophage region and confirmed a chromosomally integrated LGI2-3. It harbored a cystathionine beta-lyase gene previously only encountered in LGI2-1 of clonal complex 1 but was otherwise most closely related to LGI2. LGI2-3 harbored a novel cassette ( that, like LGI2's , was associated with lower-level tolerance to cadmium (MIC 50 μg/mL) than other cassettes (MIC ≥ 140 μg/mL). CadA sequence analysis identified two amino acids that may be important for mediating different levels of cadmium tolerance. Our findings clearly demonstrated the potential for LGI2-like islands to be harbored by non-pathogenic spp. and generate intriguing hypotheses on the genetic diversity mediated by this island and its transfer among spp.