aeromonas hydrophila secretes several extracellular proteins including enterotoxin, hemolysin and aerolysin that are associated with the bacterial virulence. previous studies have shown that two hemolytic toxins, hemolysin a and aerolysin a contribute to the virulence of aeromonas hydrophila. in the current study, a total of 50 strains of aeromonas hydrophila, including 28 (56%) strains isolate...

The aim of this study was to identify virulent Shiga toxin-producing Escherichia coli (STEC) strains isolated from faecal samples of 100 clinically healthy calves. In the present study, a total of 100 Escherichia coli (E. coli) isolates from clinically healthy calves belonging to 6 different farms located in Khorasan Razavi province, Iran, were examined for presence of virulence genes character...

In a previous study, the seasonal prevalence was reported for stx+ Escherichia coli O157:H7 in feces and on hides and carcasses of cattle at processing. Overall, 1,697 O157:H7 isolates have now been characterized for the incidence of (i) eae(O157), hlyA, stx1, and stx2 in the recovered isolates and (ii) presumptive rough and presumptive nonmotile isolates. Seven O157:H7 isolates (0.4%) lacked s...

BACKGROUND Cholera toxin (CT) and toxin-co-regulated pili (TCP) are the major virulence factors of Vibrio cholerae O1 and O139 strains that contribute to the pathogenesis of disease during devastating cholera pandemics. However, CT and TCP negative V. cholerae strains are still able to cause severe diarrheal disease in humans through mechanisms that are not well understood. METHODOLOGY/PRINCI...

The toxin HlyA is exported from Escherichia coli, without a periplasmic intermediate, by a type I system comprising an energized inner-membrane (IM) translocase of two proteins, HlyD and the traffic ATPase HlyB, and the outer-membrane (OM) porin-like TolC. These and the toxin substrate were expressed separately to reconstitute export and, via affinity tags on the IM proteins, cross-linked in vi...

Several genes involved in the lipopolysaccharide (LPS) biosynthetic pathway have been shown to affect the expression or activity of Escherichia coli hemolysin (Hly), a secreted cytotoxin that is the prototype of the RTX family of toxins. To further study this relationship, E. coli K-12 strains harboring mutations in the LPS biosynthetic genes rfaS, rfaQ, rfaJ, rfaP, and rfaC were transformed wi...