Characterization of the emerging zoonotic pathogen Arcobacter thereius by whole genome sequencing and comparative genomics

Abstract

Four Arcobacter species have been associated with human disease, and based on current knowledge, these Gram negative bacteria are considered as potential food and waterborne zoonotic pathogens. At present, only the genome of the species Arcobacter butzleri has been analysed, and still little is known about their physiology and genetics. The species Arcobacter thereius has first been isolated from tissue of aborted piglets, duck and pig faeces, and recently from stool of human patients with enteritis. In the present study, the complete genome and analysis of the A. thereius type strain LMG24486T, as well as the comparative genome analysis with 8 other A. thereius strains are presented. Genome analysis revealed metabolic pathways for the utilization of amino acids, which represent the main source of energy, together with the presence of genes encoding for respiration-associated and chemotaxis proteins. Comparative genome analysis with the A. butzleri type strain RM4018 revealed a large correlation, though also unique features. Furthermore, in silico DDH and ANI based analysis of the nine A. thereius strains disclosed clustering into two closely related genotypes. No discriminatory differences in genome content nor phenotypic behaviour were detected, though recently the species Arcobacter porcinus was proposed to encompass part of the formerly identified Arcobacter thereius strains. The report of the presence of virulence associated genes in A. thereius, the presence of antibiotic resistance genes, verified by in vitro susceptibility testing, as well as other pathogenic related relevant features, support the classification of A. thereius as an emerging pathogen.

A Polyphasic and Taxogenomic Evaluation Uncovers Arcobacter cryaerophilus as a Species Complex That Embraces Four Genomovars

“…None of the genomes showed the cadF, hecA and hecB genes that encode a fibronectin binding protein, an adhesion protein and a factor for hemolysis activation, respectively. These results agree with those obtained for the genome of A. thereius LMG 24486 T (Rovetto et al, 2017 ). The irgA and tlyA genes that encode an iron-regulated outer membrane protein and a hemolysine, respectively, were the only ones found i.e.…”

“…The genome L406 was the only one that possessed a β-lactamase gene of class D. Resistance to β-lactamic compounds have been reported in other studies (Atabay and Aydin, 2001 ; Fera et al, 2003 ) and the same β-lactamase gene is present in the genome of A. butleri RM4018. However, this gene is absent in the genome of A. thereius LMG 24486 T (Rovetto et al, 2017 ). The genome LMG 29976 was the only one that presented genes for the resistance to streptomycin/spectomycin.…”

Aliarcobacter butzleri from Water Poultry: Insights into Antimicrobial Resistance, Virulence and Heavy Metal Resistance

“…The two heptosyltransferases I and II encoded by rfaC (formerly waaC ) and rfaF (formerly waaF ) were detected in both investigated strains. These heptosyltransferases are involved in the biosynthesis of the LPS core, as described in previous publications [ 27 , 86 ]. Although heptosyltransferases are not essential, their absence leads to structural changes in the outer membrane (reduced protein content; increased sensitivity towards hydrophobic agents) and sometimes to a rough phenotype [ 87 ].…”

Genomic Characterization of Arcobacter butzleri Isolated From Shellfish: Novel Insight Into Antibiotic Resistance and Virulence Determinants

“…In both genomes, we identified orthologues of waa C and waa F genes, which are described as virulence determinant in A. thereius (Rovetto et al, 2017), but also in Pseudomonas aeruginosa , E. coli , Klebsiella pneumonia , and other Campylobacteraceae (Oldfield et al, 2002; DeLucia et al, 2011; Nilsson et al, 2018). waaF codes for a predicted ADP-heptose–LPS heptosyltransferase ( Ab 55 D3M61_00085; Ab 6V D3M75_11180), involved in the biosynthesis of lipooligosaccharide (LOS); waaC codes for a lipopolysaccharide heptosyltransferase ( Ab 55 D3M61_00195; Ab 6V D3M75_05185), which catalyzes the transfer of sugar moieties from activated donor molecules to specific acceptor molecules, forming glycosidic bonds.…”