Occurrence of virulence-associated genes in Arcobacter butzleri and Arcobacter cryaerophilus isolates from foodstuff, water, and clinical samples within the Czech Republic

Bacteria of the Arcobacter (A.) genus, originating mainly from food and water, are dreaded germs for humans as well as animals. However, the virulence of these bacteria has not been fully elucidated yet. This study looked at the occurrence of eight virulence-associated factors (ciaB, cj1349, pldA, irgA, hecA, tlyA, mviN, hecB) in a total of 80 isolates of Arcobacter butzleri and 22 isolates of A. cryaerophilus. The isolates were derived from food, water, and clinical samples. A polymerase chain reaction using specific primers was used to detect these virulence-associated genes. The presence of all genes in the isolates of A. butzleri (98.8% ciaB, 95.0% cj1349, 98.8% pldA, 22.5% irgA, 31.3% hecA, 95.0% tlyA, 97.5% mviN, 38.8% hecB) and A. cryaerophilus (95.5% ciaB, 0.0% cj1349, 9.1% pldA, 0.0% irgA, 0.0% hecA, 31.8% tlyA, 90.9% mviN, 0.0% hecB) was monitored. Among the tested isolates, there were 13 isolates (12.7%) of A. butzleri, in which the presence of all eight virulence-associated genes was recorded in the genome. In contrast, in one A. cryaerophilus strain, none of the observed genes were detected. The presence of ciaB and mviN genes was significantly more frequent in A. cryaerophilus isolates than other genes (P<0.05). In general, more virulence-associated genes have been detected in A. butzleri isolates compared to A. cryaerophilus. The most common gene combination (ciaB, cj1349, pldA, tlyA, mviN) was detected in case of 39 isolates. In 50.0% of A. butzleri isolates derived from clinical samples, all eight virulence-associated genes were significantly more frequently detected (P<0.05). The tlyA gene occurred significantly more frequent in A. butzleri isolates from meat and water samples and irgA and hecB genes in clinical samples. Therefore, our study provides information about occurrence of virulence-associated genes in genome of Arcobacter isolates. These findings could be hazardous to human health, because the presence of virulence-associated genes is the assumption for potential dangerousness of these bacteria. Our results indicate high incidence of virulence-associated genes in Arcobacter genomes and hence potentially pathogenic properties of the studied strains.