Recently, it has been reported that flagellins of H7, H8, H9, H11, and H21 serotypes fromE

Recently, it has been reported that flagellins of H7, H8, H9, H11, and H21 serotypes fromE. TNF-, and IL-10 between 95100% using 100 ng of protein. A transfection assay using 293-hTLR5 cells showed IL-8 release of 197 pg/ml and suppression in the secretion of IL-8 when anti-hTLR5-IgA antibodies were used at different concentrations. These observations suggest that flagella and flagellin are involved in an inflammatory response dependent on TLR5 acknowledgement, which could contribute to the pathogenesis of the bacteria. == Introduction == Cronobacterspp. (formerlyEnterobacter sakazakii) are facultative, Gram-negative, non-spore forming, motile microorganisms that belongs to theGammaproteobacteriaclass and to the Enterobacteriaceae family[1]. Currently, based on the phenotypic and genotypic characterization of this genus, seven species have been explained:Cronobacter sakazakii,C.malonaticus,C.dublinensis,C.muytjensii,C. turicensis,C. universalis, andC. condimenti[2],[3],[4],[5],[6].Cronobacteris an ubiquitous organism that can be isolated from a wide range of environments, including water, ground, vacuum cleaner dust, air samples, rhizosphere, and a variety of processed foods and fresh produce[7],[8],[9]. The mechanisms of transmission of these bacteria have been associated with the ingestion of contaminated reconstituted formula, but it has also been isolated from a variety of Rabbit Polyclonal to BRP44L foods (from animal and vegetable origin)[8],[10]. Identification amongCronobacterspecies is hard due to the diversity of the genus. A Multi Locus Sequence Typing (MLST) of seven housekeeping genes was originally developed for the differentiation betweenC. sakazakiiandC. malonaticus, two species that could not be distinguished according to the 16S rDNA[11]. This molecular tool has provided an effective typing plan for theCronobactergenus, showing a high level of discernment between the isolates. Interestingly, MLST has identifiedC. sakazakiiST4 as the predominant sequence type isolated from cerebral spinal fluid from meningitis cases[12]. Cronobacterspecies are considered opportunistic pathogens that have been implicated in life threatening diseases in humans, across all group ages[13]. However, particularly neonates of low-birth excess weight are the major risk group recognized with a high mortality rate (4080%)[14]. This pathogen is a rare cause of neonatal meningitis, septicemia, and necrotizing enterocolitis in infants[15]. Although several genes have been recognized to be involved in the virulence ofCronobacterspecies, we are still far from understanding their pathogenesis. On the other hand, not allCronobacterspecies has been linked with infections and the severity of virulence varies among strains.Cronobacterspecies vary in their virulence with respect to the invasion of intestinal cells, enterotoxin production, survival in macrophages, and serum resistance[16],[17],[18],[19]. Recently, it has been suggested that this outer membrane proteins OmpA and OmpX fromC. sakazakiiare involved in basolateral invasion of human enterocyte-like Caco-2 Amylin (rat) and intestinal INT407 epithelial cells[19],[20],[21]. These data are the first statement ofC. sakazakiivirulence determinants essential for invasion that may be critical for the pathogenicity of this microorganism. Other studies showed the ability ofCronobacterspp. to adhere to two epithelial cell lines (HEp-2 and Caco-2 cells), as well as to a brain microvascular endothelial cell collection[17]. In addition,C. sakazakiiutilizes dendritic cells (DCs) as a vehicle for propagation and survival, hence evading potential immune surveillance[22]. Recently, the role of PMNs (polymorphonuclear leukocytes) and macrophages was examined in acuteC. sakazakiiinduced mouse model of NEC (necrotizing enterocolitis). Oral feeding ofC.sakazakiiresults in acute intestinal inflammation and death in newborn mouse pups; the presence and recruitment of PMNs and macrophages to the lamina propria is important for clearance of the bacteria during initial says of the contamination. Furthermore, their absence exacerbates mucosal injury by increasing the levels of pro-inflammatory cytokines[23].Cronobacterspp. are also Amylin (rat) involved in biofilm formation on glass, stainless steel, polyvinyl chloride, polycarbonate, silicone, and enteral feeding tubes which could represent the vehicle of contamination[24],[25]. The survival ofC. sakazakiiin biofilms is Amylin (rat) due to the presence of multiple nutritional factors and/or different environmental conditions, which is associated with the increase in antibiotic resistance[26],[27]. In.