Distribution of 13 virulence genes among clinical and environmental Aeromonas spp. in Western Australia

Abstract

We evaluated the pathogenic potential of 98 clinical and 31 environmental Aeromonas isolates by detecting the presence of 13 virulence genes using a polymerase chain reaction (PCR)-based method. The majority (96 %) of the strains contained at least one of the virulence genes. The overall distribution was aerA/haem (77 %), alt (53 %), lafA (51 %), ast (39 %), flaA (32 %), aspA (29 %), vasH (26 %), ascV (16 %) and aexT (13 %). No amplification products were detected for the genes encoding a bundle-forming pilus (BfpA and BfpG) or a Shiga-like toxin (stx-1 and stx-2). Five or more virulence genes were detected in 42 % of environmental and 24 % of clinical isolates. Among the major species, 48 % of A. hydrophila and 42 % of A. dhakensis isolates harboured five or more virulence genes compared with 19 % in A. veronii bv. sobria and none in A. caviae isolates. Our results suggest that, in Western Australia, strains of A. dhakensis and A. hydrophila are potentially more virulent than those of A. veronii bv. sobria and A. caviae, although the pathogenic potential of Aeromonas spp. is probably strain- rather than species-dependent.

Aeromonas hydrophilaandAeromonas veroniicause motileAeromonassepticaemia in the cultured Chinese sucker,Myxocyprinus asiaticus

“…In this study, A. hydrophila was more pathogenic than A. veronii , perhaps because the former had more key virulence factors than the latter. However, genes coding for LafA, BfpA, BfpG, VasH, Stx‐1 and Stx‐2 were not detected in either of the two isolates, which is likely associated with the low occurrence of these genes in Aeromonas strains (Aravena et al, ; Sechi et al, ). In short, we suggest that bacterial genome analysis is a feasible method for the deep exploration of the relationship between the pathogenicity and distribution of virulence factors.…”

“…Polymerase chain reaction was used to determine the distribution of 16 genes coding for lateral ( lafA ), polar ( flaA ), heat‐labile ( alt ) and heat‐stable ( ast ) cytotoxic enterotoxin; aerolysin ( aerA ); serine protease ( aspA ); components of type three ( aexT and ascV ) and type six ( vasH ) secretion systems; bundle‐forming pilus ( bfpA and bfpG ); a Shiga‐like toxin ( stx‐1 and stx‐2 ); outer membrane protein A ( ompA ); lipase ( lip ); and haemolysin ( hlyA ) in the isolated pathogenic strains. Fragments of these genes were amplified following the methods described in Aravena ().…”

Diverse Profiles of N‐acyl Homoserine l‐Lactones, Biofilm, Virulence Genes and Integrons in Food‐Borne Aeromonas Isolates

“…The pathogenesis of Aeromonas infection is multifactorial and an extensive array of putative virulence factors {heat‐labile ( alt ) and heat‐stable ( ast ) cytotonic enterotoxins, glycerophospholipid‐cholesterol acyltransferase ( gcat ), serine protease ( ser ), lateral ( lafA ), and polar ( fla ) flagella} that may play a significant role in the development of disease have been detected and studied in several Aeromonas spp. (Nawaz and others ; Aravena‐Román and others ). The multifactorial virulence determinants of Aeromonas include cell‐associated factors (flagella, lipopolysaccharide, adhesions, and pili), extracellular factors (exotoxins and extra‐cellular enzymes), siderophores, and secretion systems (Janda and Abbott ).…”

Characterization of a new strain of Aeromonas dhakensis isolated from diseased pacu fish (Piaractus mesopotamicus) in Brazil

“…) and Australia (Aravena‐Roman et al . ). Recently, A dhakensis was associated with fatal haemorrhagic necrotizing pneumonia and sepsis in a Risso's dolphin ( Grampus griseus ) from the Mediterranean Sea in Spain, increasing the number of potential hosts of this species (Perez et al .…”

“…This species (either as the newly classified A. dhakensis or as a subspecies of A. hydrophila or as A. aquariorum) has usually been described from human faeces, clinical sources, diseased fish or from environmental water in Europe (Esteve, Alcaide & Blasco 2012;Esteve, Alcaide & Gimenez 2015;Lobova et al 2015), Asia (Huys et al 2002;Puah et al 2013;Wu et al 2015), Africa (Ghenghesh et al 2014), Mexico (Soto-Rodriguez et al 2013) and Australia (Aravena-Roman et al 2014). Recently, A dhakensis was associated with fatal haemorrhagic necrotizing pneumonia and sepsis in a Risso's dolphin (Grampus griseus) from the Mediterranean Sea in Spain, increasing the number of potential hosts of this species (Perez et al 2015).…”