Duplication and variation of the thermostable direct haemolysin
(tdh) gene in Vibrio parahaemolyticus.
Out of 100 isolates, all produced haemolysin
, 85 isolates produced gelatinase, 60 isolates produced bile esculin, 06 isolates produced deoxyribonuclease and 17 isolates produced biofilm.
Several reasons explain the differences in the percentage of haemolysin
production by UPEC like: source of blood, type of haemolysin
produced, source of bacteria and method to screen the production ability (Al-Chalabi et al., 2010).
Bergamin and Kiosoglous (2017) reported on the role of virulence factors, such as adhesins, aerobactin, haemolysin
, K-capsule, and resistance to serum killing.
The 'rose milk' observed could be associated with intravascular haemolysis by the toxin haemolysin
, damage to vascular endothelial cells in udder parenchyma by pathogenic serovar like L.
All the strains isolated from infections in Galicia were characteristically tdh positive and trh negative, the only exceptions being the strains belonging to sequence type (ST) 36 isolated during the 2012 outbreak, which were positive for both haemolysin
, which would explain the invasive nature of these bacterium appears to be the most likely candidate in these serotypes.3 Cytotoxic and haemolytic activity has been previously demonstrated in a Non-O1 strain causing bacteraemia in a patient.4 It has also been postulated that the invasive nature of the bacteria can be attributed to a toxin named the zot toxin which functions by disabling the tight junctions between the epithelial cells of the intestine.5 Infections in humans arise most commonly due to ingestion of contaminated water and raw or undercooked seafood.
. Pure cultures of the bacterial isolates were grown on the surface of 5% defibrinated sheep blood agar in a trypticase soy agar base (Difco) and incubated at 37[degrees]C for 72 h.
The microbial growing is suspected, by inconspicuous hemolytic zones at 24 hours (h) of incubation at 37[degrees]C on bovine blood agar, thereafter at 48 h and with an exhaustive macroscopic examination, it is possible to see white pin point colonies with 1-2 mm diameter, surrounded by a more prominent total ([beta]) hemolysis [9, 46, 57], it is partially acid-alcohol resistant and has a fermentative metabolism ; unlike clinical samples, cultures do not have a characteristic odor; CAMP test is helpful to confirm the identification [13,31] and differentiation from Arcanobacterium haemolyticum, which inhibit Staphylococcus aureus [beta] haemolysin
intermedius) carry several virulence factors i.e coagulase, clumping factors, haemolysin
and leukotoxin, pyogenic toxins comprising staphylococcal enterotoxins, toxic shock syndrome toxin 1, and S.
Some of these virulence genes include the outer membrane protein (ompW) gene, toxR regulon, Zonula occludens toxin (zot) gene, pore-forming toxin haemolysin
(hlyA), and the heat-stable enterotoxin (stn/sto) gene.
Maha et al., "Candida albicans Isolates from a Malaysian hospital exhibit more potent phospholipase and haemolysin
activities than non-albicans Candida isolates," Tropical Biomedicine, vol.