Novel virulence, antibiotic resistance and toxin gene-specific PCR-based assays for rapid pathogenicity assessment of Arcobacter faecis and Arcobacter lanthieri

Citation

Zambri, M., Cloutier, M., Adam, Z., Lapen, D.R., Wilkes, G., Sunohara, M., Topp, E., Talbot, G., Khan, I.U.H. (2019). Novel virulence, antibiotic resistance and toxin gene-specific PCR-based assays for rapid pathogenicity assessment of Arcobacter faecis and Arcobacter lanthieri. BMC Microbiology, [online] 19(1), http://dx.doi.org/10.1186/s12866-018-1357-7

Plain language summary

Our lab discovered Arcobacter faecis and A. lanthieri two newly classified species of genus Arcobacter where this study was conducted to assess their potential pathogenic health impacts to humans and animals by investigating virulence, antibiotic resistance and toxin (VAT) genes. We developed species- and gene-specific molecular assays for the detection of six virulence, two antibiotic resistance, and three toxin genes in these two target species by optimizing specificity, sensitivity as well as evaluation and validation of eleven mono- and multiplex DNA-based Polymerase Chain Reaction (PCR) assays in A. faecis and A. lanthieri strains isolated from various fecal and agricultural water sources. Our study results show that, overall, all ten and eleven target VAT genes were detected with high frequency in field isolates suggest that they are potentially pathogenic strains. These findings indicate that these two species can pose health risks to humans and animals. In conclusion, the developed PCR assays are simple, rapid, reliable and sensitive for the simultaneous assessment of the potential pathogenicity and antibiotic resistance profiling in these two species. Also, these novel PCR assays can be useful in diagnostic and analytical laboratories to determine the pathotypes and assessment of the virulence and toxin factors associated to human and animal infections.

Abstract

Background: Arcobacter faecis and A. lanthieri are two newly classified species of genus Arcobacter. The prevalence and distribution of virulence, antibiotic resistance and toxin (VAT) genes in these species are required to assess their potential pathogenic health impacts to humans and animals. This study (i) developed species- and gene-specific primer pairs for the detection of six virulence, two antibiotic resistance, and three toxin genes in two target species; (ii) optimized eight single-tube multiplex and three monoplex PCR protocols using the newly developed species- and gene-specific primers; and (iii) conducted specificity and sensitivity evaluations as well as validation of eleven mono- and multiplex PCR assays by testing A. faecis (n= 29) and A. lanthieri (n= 10) strains isolated from various fecal and agricultural water sources to determine the prevalence and distribution of VAT genes and assess the degree of pathogenicity within the two species. Results: Detection of all ten and eleven target VAT genes, and expression of cytolethal distending toxin (cdtA, cdtB and cdtC) genes in A. faecis and A. lanthieri reference strains with high frequency in field isolates suggest that they are potentially pathogenic strains. These findings indicate that these two species can pose a health risk to humans and animals. Conclusions: The study results show that the developed mono- and multiplex PCR (mPCR) assays are simple, rapid, reliable and sensitive for the simultaneous assessment of the potential pathogenicity and antibiotic resistance profiling of tet(O) and tet(W) genes in these two newly discovered species. Also, these assays can be useful in diagnostic and analytical laboratories to determine the pathotypes and assessment of the virulence and toxin factors associated to human and animal infections.