Distribution and expression of virulence genes in potentially pathogenic bacteria isolated from seafood in Thailand

Abstract

Since seafood can be a reservoir for diverse pathogenic bacteria, the risk to human health associated with seafood merits evaluation. The potentially pathogenic bacteria were isolated from seafood in Thailand. The 40 obtained strains were distinguished by ERIC-PCR fingerprints and identified to the species level by the VITEK 2 system. Their 16S rRNA gene had 97.74-99.79% nucleotide sequence identities to those of bacteria in 11 genera including Aeromonas, Citrobacter,

Identification, Characterization, and Virulence Gene Expression of Marine Enterobacteria in the Upper Gulf of Thailand

“…The presumptive enterobacterial strains were distinguished by ERIC-PCR which has been found to be extremely sensitive and can detect minor differences among strains of the same bacterial genus and species [ 29 ]. The UPGMA dendrogram ( Figure S1 ) constructed from ERIC-PCR fingerprints presents a high level of diversity among 113 strains as showing 20% similarity.…”

“…Virulence genes can be classified into three types including (1) true virulence genes which encode factors or enzymes producing factors that are involved in bacteria-host interaction and directly cause the pathological damage during infection; (2) virulence-associated genes which encode factors or enzymes producing factors that control virulence gene expression or stimulate virulence factors or are essential for the activity of true virulence factors; and (3) virulence life-style genes which encode factors or enzymes producing factors that promote host colonization or enable evasion of the host immune system or enable interaction survival or employ host-factors for the advantages of survival [ 27 ]. Previous reports demonstrated that the expression of virulence genes was affected by several factors such as (1) nutrient starvation [ 28 , 29 , 30 ]; (2) osmotic agents (NaCl, sucrose, and glucose) [ 29 , 31 , 32 , 33 , 34 , 35 , 36 ]; (3) oxygen [ 37 ]; (4) temperature [ 31 , 38 ]; (5) growth phase [ 29 , 39 , 40 ]; (6) kind of carbon source [ 41 , 42 ]; (7) pH [ 43 ]; (8) sodium glycocholate [ 44 ]; and (9) L-glutamine [ 45 ]. Besides being a major problem in public health concern, enterobacteria are also highlighted for their application potential.…”