Coli K1 Research Articles

Lipocalin 2 regulates intestine bacterial survival by interplaying with siderophore in a weaned piglet model of Escherichia coli infection.

Iron is an essential nutrient that facilitates cell proliferation and growth, which plays a pivotal role in modulating the battle for survival between mammalian hosts and their pathogens. Pathogenic bacteria secrete siderophores to acquire iron from the host. However, lipocalin 2 (Lcn2), a siderophore-binding antimicrobial protein, binds to siderophores to prevent bacterial uptake of iron, which is critical for the control of systemic infection with Escherichia coli (E. coli). But few studies focus on the anti-infective response of Lcn2 in the intestines by inhibiting bacterial proliferation based on microbial iron metabolism. In this study, we showed that iron was sequestrated within cells in a piglet model of E. coli K88 infection. Siderophores was produced following E. coli K88 infection and siderophore-related genes expression was upregulated in iron-deficiency environment in vitro. Meanwhile, we found that Lcn2 expression was rapidly and robustly induced in jejunum by E. coli K88 infection and could be stimulated by IL-17 and IL-22. Furthermore, both Lcn2 induced in epithelial cells IPEC-1 and added exogenously as a recombinant protein could inhibit the growth of E. coli. We can conclude that Lcn2 is a crucial component of mucosal immune defense against intestinal infection with E. coli K88.

Temporal changes of oxidative stress markers in Escherichia coli K1-induced experimental meningitis in a neonatal rat model.

Despite advances in antimicrobial therapy and advanced critical care neonatal bacterial meningitis has a mortality rate of over 10% and induces neurological sequelae in 20-50% of cases. Escherichia coli K1 (E. coli K1) is the most common gram-negative organism causing neonatal meningitis and is the second most common cause behind group B streptococcus. We previously reported that an E. coli K1 experimental meningitis infection in neonatal rats resulted in habituation and aversive memory impairment and a significant increase in cytokine levels in adulthood. In this present study, we investigated the oxidative stress profile including malondialdehyde (MDA) levels, carbonyl protein formation, myeloperoxidase activity (MPO) activity, superoxide dismutase (SOD) activity and catalase (CAT) activity 6, 12, 24, 48, 72 and 96h after E. coli K1 experimental meningitis infection. In addition, sulfhydryl groups, nitrite and nitrate levels and activity of the mitochondrial respiratory chain enzymes were also measured in the frontal cortex and hippocampus of neonatal rats. The results from this study demonstrated a significant increase in MDA, protein carbonyls and MPO activity and a simultaneous decrease in SOD activity in the hippocampus of the neonatal meningitis survivors but the same was not observed in frontal cortex. In addition, we also observed a significant increase in complex IV activity in the hippocampus and frontal cortex of meningitis survivor rats. Thus, the results from this study reaffirmed the possible role of oxidative stress, nitric oxide and its related compounds in the complex pathophysiology of E. coli K1-induced bacterial meningitis.

Molecular recognition of glyconanoparticles by RCA and E. coli K88 - designing transports for targeted therapy.

The targeted drug delivery has been studied as one of the main methods in medicine to ensure successful treatments of diseases. Pharmaceutical sciences are using micro or nano carriers to obtain a controlled delivery of drugs, able to selectively interact with pathogens, cells or tissues. In this work, we modified bovine serum albumin (BSA) with lactose, obtaining a neoglycan (BSA-Lac). Subsequently, we synthesized glyconanoparticles (NPBSA-Lac) with the premise that it would be recognized by microbial galactose specific lectins. NPBSA-Lac were tested for bio-recognition with adhesins of E. coli K88 and Ricinus communis agglutinin I (RCA). Glycation of BSA with lactose was analyzed by electrophoresis, infrared spectroscopy and fluorescence. Approximately 41 lactoses per BSA molecule were estimated. Nanoparticles were obtained using water in oil emulsion method and spheroid morphology with a range size of 300-500 nm was observed. Specific recognition of NPBSA-Lac by RCA and E. coli K88 was displayed by aggregation of nanoparticles analyzed by dynamic light scattering and atomic force microscopy. The results indicate that the lactosylated nanovectors could be targeted at the E. coli K88 adhesin and potentially could be used as a transporter for an antibacterial drug.

The effects of cytotoxic necrotizing factor 1 expression in the uptake of Escherichia coli K1 by macrophages and the onset of meningitis in newborn mice

ABSTRACTMacrophages are a permissive niche for E. coli K1 multiplication for which the interaction of the bacterial outer membrane protein A and its cognate receptor CD64 are critical. Using in vitro immunofluorescence and live microscopy with ex vivo macrophage cultures from RFP-Lifeact mice, we show that cytotoxic necrotizing factor 1 (CNF1) secreted by E. coli K1 sequesters cellular actin toward microspike formation, thereby limiting actin availability for OmpA-mediated bacterial invasion. Surprisingly, the observed effects of CNF1 occur despite the absence of 67-kDa laminin receptor in macrophages. Concomitantly, the CNF1 deletion mutant of E. coli K1 (Δcnf1) invades macrophages and the brains of newborn mice in greater numbers compared to wild-type. However, the Δcnf1 strain induces less severe pathology in the brain. These results suggest a novel role for CNF1 in limiting E. coli K1 entry into macrophages while exacerbating disease severity in the brains of newborn mice.

The molecular characterisation of Escherichia coli K1 isolated from neonatal nasogastric feeding tubes.

BackgroundThe most common cause of Gram-negative bacterial neonatal meningitis is E. coli K1. It has a mortality rate of 10–15 %, and neurological sequelae in 30–50 % of cases. Infections can be attributable to nosocomial sources, however the pre-colonisation of enteral feeding tubes has not been considered as a specific risk factor.MethodsThirty E. coli strains, which had been isolated in an earlier study, from the residual lumen liquid and biofilms of neonatal nasogastric feeding tubes were genotyped using pulsed-field gel electrophoresis, and 7-loci multilocus sequence typing. Potential pathogenicity and biofilm associated traits were determined using specific PCR probes, genome analysis, and in vitro tissue culture assays.ResultsThe E. coli strains clustered into five pulsotypes, which were genotyped as sequence types (ST) 95, 73, 127, 394 and 2076 (Achman scheme). The extra-intestinal pathogenic E. coli (ExPEC) phylogenetic group B2 ST95 serotype O1:K1:NM strains had been isolated over a 2 week period from 11 neonates who were on different feeding regimes. The E. coli K1 ST95 strains encoded for various virulence traits associated with neonatal meningitis and extracellular matrix formation. These strains attached and invaded intestinal, and both human and rat brain cell lines, and persisted for 48 h in U937 macrophages. E. coli STs 73, 394 and 2076 also persisted in macrophages and invaded Caco-2 and human brain cells, but only ST394 invaded rat brain cells. E. coli ST127 was notable as it did not invade any cell lines.ConclusionsRoutes by which E. coli K1 can be disseminated within a neonatal intensive care unit are uncertain, however the colonisation of neonatal enteral feeding tubes may be one reservoir source which could constitute a serious health risk to neonates following ingestion.Electronic supplementary materialThe online version of this article (doi:10.1186/s12879-015-1210-7) contains supplementary material, which is available to authorized users.

K88 Fimbrial Adhesin Targeting of Microspheres Containing Gentamicin Made with Albumin Glycated with Lactose.

The formulation and characterization of gentamicin-loaded microspheres as a delivery system targeting enterotoxigenic Escherichia coli K88 (E. coli K88) was investigated. Glycated albumin with lactose (BSA-glucose-β (4-1) galactose) was used as the microsphere matrix (MS-Lac) and gentamicin included as the transported antibiotic. The proposed target strategy was that exposed galactoses of MS-Lac could be specifically recognized by E. coli K88 adhesins, and the delivery of gentamicin would inhibit bacterial growth. Lactosylated microspheres (MS-Lac1, MS-Lac2 and MS-Lac3) were obtained using a water-in-oil emulsion, containing gentamicin, followed by crosslinking with different concentrations of glutaraldehyde. Electron microscopy displayed spherical particles with a mean size of 10–17 µm. In vitro release of gentamicin from MS-Lac was best fitted to a first order model, and the antibacterial activity of encapsulated and free gentamicin was comparable. MS-Lac treatments were recognized by plant galactose-specific lectins from Ricinus communis and Sophora japonica and by E. coli K88 adhesins. Results indicate MS-Lac1, produced with 4.2 mg/mL of crosslinker, as the best treatment and that lactosylated microsphere are promising platforms to obtain an active, targeted system against E. coli K88 infections.

Bioluminescent imaging reveals novel patterns of colonization and invasion in systemic Escherichia coli K1 experimental infection in the neonatal rat.

Key features of Escherichia coli K1-mediated neonatal sepsis and meningitis, such as a strong age dependency and development along the gut-mesentery-blood-brain course of infection, can be replicated in the newborn rat. We examined temporal and spatial aspects of E. coli K1 infection following initiation of gastrointestinal colonization in 2-day-old (P2) rats after oral administration of E. coli K1 strain A192PP and a virulent bioluminescent derivative, E. coli A192PP-lux2. A combination of bacterial enumeration in the major organs, two-dimensional bioluminescence imaging, and three-dimensional diffuse light imaging tomography with integrated micro-computed tomography indicated multiple sites of colonization within the alimentary canal; these included the tongue, esophagus, and stomach in addition to the small intestine and colon. After invasion of the blood compartment, the bacteria entered the central nervous system, with restricted colonization of the brain, and also invaded the major organs, in line with increases in the severity of symptoms of infection. Both keratinized and nonkeratinized surfaces of esophagi were colonized to a considerably greater extent in susceptible P2 neonates than in corresponding tissues from infection-resistant 9-day-old rat pups; the bacteria appeared to damage and penetrate the nonkeratinized esophageal epithelium of infection-susceptible P2 animals, suggesting the esophagus represents a portal of entry for E. coli K1 into the systemic circulation. Thus, multimodality imaging of experimental systemic infections in real time indicates complex dynamic patterns of colonization and dissemination that provide new insights into the E. coli K1 infection of the neonatal rat.

Livedo Reticularis: A Presenting Sign of Escherichia Coli Sepsis in a Newborn

Livedo reticularis is a red cutaneous netlike pattern that is caused by abnormalities of the microvascularization and can be associated with many other potential systemic etiologies. We describe a case of a newborn that presented with livedo reticularis on his first day of life without any obvious systemic signs. The livedo reticularis was associated with Escherichia Coli K1 meningitis as revealed by laboratory tests. Clinical infectious signs developed a few hours later. Despite appropriate antibiotics therapy, he died on his second day because of sepsis and disseminated intravascular coagulation. Cerebrospinal fluid culture, blood culture, and culture of samples from trachea showed the presence of Escherichia Coli serotype K1 with many virulence determinants. Conclusion: In newborn, livedo reticularis must not be considered as physiological, but as a potential sign of unknown severe bacterial infection. Thus, the presence of livedo reticularis must require urgent laboratory tests.

Effects of casein glycomacropeptide supplementation on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets.

Casein glycomacropeptide (CGMP) is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance, intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88 (E. coli K88) challenged piglets. Eighteen weaning piglets were randomly assigned to three groups. Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8–10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain (P < 0.05), increase in pathogenic bacteria amounts in intestinal contents (P < 0.05), intestinal morphology (P > 0.05) and barrier permeability damage (P < 0.05), and acute inflammatory response (P < 0.05) induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.

Function of KpsS, KpsC, and NeuE in Escherichia coli K1 Polysialic Acid Biosynthesis

Pathogenic Escherichia coli are often encapsulated with acidic polysaccharides such as polysialic acid. We have shown that four genes, kpsS, kpsC, neuE and neuS, in the E. coli K1 gene cluster are essential for initiation and elongation in E. coli K1 polysialic acid biosynthesis. NeuS is a polysialyltransferase. A previous report demonstrated that homologues of kpsC and kpsS gene products in N. meningitidis are cytidine 5′‐monophosphate‐2‐keto‐3‐deoxyoctulosonate (CMP‐KDO) transferases. These enzymes are involved in the biosynthesis of the putative glycolipid terminus of terminus of polysialic acid. Our objective in this report is to determine the function of KpsC, KpsS, and NeuE of E. coli in initiation of polysialic acid synthesis. We have successfully expressed in a soluble form and purified KpsC, KpsS, and NeuE of E. coli K1 to near homogeneity. This is the first time these full length membrane proteins have been expressed in a soluble form. We used HPLC and TLC methods to demonstrate that E. coli K1 KpsS and KpsC can transfer KDO to a fluorescence glycolipid acceptor substrate. The fluorescent products of KpsS and KpsC were isolated and used to investigate the function of the NeuE in polysialic acid biosynthesis.

Research progress in the mechanism of Escherichia coli K1 translocation of the blood-brain barrier

Neonatal purulent meningitis is one of the severe infectious diseases of the central nervous system.Escherichia coli K1(E.coli K1)strain is the most common Gram-negative bacteria which leads to neonatal purulent meningitis.The mechanism of E. coli K1 translocation of the blood-brain barrier(BBB)include the high degree of bacteremia, invasion of brain microvessel endothelia cell by E. coli K1, receptor-mediated pinocytosis transport for E. coli K1 and the living bacteria across the BBB.The current knowledge on the mechanisms underlying the successful E. coli K1 translocation of the BBB are summarized in this review. Key words: Purulent meningitis; Neonate; Escherichia coli K1; Blood-brain barrier; Mechanism

B lymphocytes activation in GALT (Gut Associated Lymphatic Tissue) in immunized hens with Escherichia coli K88.

B lymphocytes activation in GALT (Gut Associated Lymphatic Tissue) in immunized hens with Escherichia coli K88.

Utility of latex agglutination test (LAT) in detecting acute bacterial meningitis against culture as gold standard

Background: Bacterial meningitis is a medical emergency. It is a major cause of death and disability worldwide. Immediate steps must be taken to establish the cause and initiate effective therapy. Though Gram staining is essential in diagnosis of meningitis, some cases may be missed. Culture and latex agglutination tests (LATs) help to overcome this disadvantage. Objective: This study was conducted to find out the sensitivity of the LAT in acute bacterial meningitis against culture as the gold standard. Materials and Methods: Cerebrospinal fluid (CSF) samples were collected aseptically in dry, sterile bottles from all cases of bacterial meningitis by lumbar puncture from August 2011 to December 2013. They were subjected to cell count, Gram staining, culture and LAT. Results: Out of 538 samples, aetiological agents were identified by Gram stain and culture or LAT in 52 cases. Streptococcus pneumoniae was isolated in 22 (42%), Haemophilus influenzae type b in 14 (26.9%), Neisseria meningitidis in three (5.6%), Group B streptococci in three (5.6%), Klebsiella pneumoniae in six (11.5%), Acinetobacter baumannii in two (3.84%) and Escherichia coli in two (3.84%) cases. In the present study, the LAT for H. influenzae type b; Streptococcus pneumoniae; Neisseria meningitidis A, B, C, Y and W135; Group B streptococci; and E. coli K1 antigen had a sensitivity of 74.1%, specificity of 95.8%, positive predictive value 52.1% and negative predictive value 98.3%. Conclusion: LAT cannot replace the utility of culture. Despite its drawbacks, LAT is a simple, rapid procedure, suitable to be used as an adjunct laboratory test for establishing the aetiological diagnosis of bacterial meningitis, particularly in partially treated cases.

The Interaction of N-Glycans in Fcγ Receptor I α-Chain with Escherichia coli K1 Outer Membrane Protein A for Entry into Macrophages

Neonatal meningitis, caused by Escherichia coli K1, is a serious central nervous system disease. We have established that macrophages serve as permissive niches for E. coli K1 to multiply in the host and for attaining a threshold level of bacterial load, which is a prerequisite for the onset of the disease. Here, we demonstrate experimentally that three N-glycans in FcγRIa interact with OmpA of E. coli K1 for binding to and entering the macrophages. Adoptive transfer of FcγRIa(-/-) bone marrow-derived macrophages transfected with FcγRIa into FcγRIa(-/-) newborn mice renders them susceptible to E. coli K1-induced meningitis. In contrast, mice that received bone marrow-derived macrophages transfected with FcγRIa in which N-glycosylation sites 1, 4, and 5 are mutated to alanines exhibit resistance to E. coli K1 infection. Our molecular dynamics and simulation studies predict that N-glycan 5 exhibits strong binding at the barrel site of OmpA formed by loops 3 and 4, whereas N-glycans 1 and 4 interact with loops 1, 3, and 4 of OmpA at tip regions. Molecular modeling data also suggest no role for the IgG binding site in the invasion process. In agreement, experimental mutations in IgG binding site had no effect on the E. coli K1 entry into macrophages in vitro or on the onset of meningitis in newborn mice. Together, this integration of experimental and computational studies reveals how the N-glycans in FcγRIa interact with the OmpA of E. coli K1 for inducing the disease pathogenesis.

A proteinaceous fraction of wheat bran may interfere in the attachment of enterotoxigenic E. coli K88 (F4+) to porcine epithelial cells.

Wheat bran (WB) from Triticum aestivum has many beneficial effects on human health. To the best of our knowledge, very little has been published about its ability to prevent pathogenic bacterial adhesion in the intestine. Here, a WB extract was fractionated using different strategies, and the obtained fractions were tested in different in vitro methodologies to evaluate their interference in the attachment of enterotoxigenic Escherichia coli (ETEC) K88 to intestinal porcine epithelial cells (IPEC-J2) with the aim of identifying the putative anti-adhesive molecules. It was found that a proteinaceous compound in the >300-kDa fraction mediates the recognition of ETEC K88 to IPEC-J2. Further fractionation of the >300-kDa sample by size-exclusion chromatography showed several proteins below 90 kDa, suggesting that the target protein belongs to a high-molecular-weight (MW) multi-component protein complex. The identification of some relevant excised bands was performed by mass spectrometry (MS) and mostly revealed the presence of various protease inhibitors (PIs) of low MW: Serpin-Z2B, Class II chitinase, endogenous alpha-amylase/subtilisin inhibitor and alpha-amylase/trypsin inhibitor CM3. Furthermore, an incubation of the WB extract with ETEC K88 allowed for the identification of a 7S storage protein globulin of wheat, Globulin 3 of 66 kDa, which may be one of the most firmly attached WB proteins to ETEC K88 cells. Further studies should be performed to gain an understanding of the molecular recognition of the blocking process that takes place. All gathered information can eventually pave the way for the development of novel anti-adhesion therapeutic agents to prevent bacterial pathogenesis.

Identification of minimum carbohydrate moiety in N-glycosylation sites of brain endothelial cell glycoprotein 96 for interaction with Escherichia coli K1 outer membrane protein A

Bacterial meningitis is a serious central nervous system infection and Escherichia coli K1 (E. coli K1) is one of the leading etiological agents that cause meningitis in neonates. Outer membrane protein A (OmpA) of E. coli K1 is a major virulence factor in the pathogenesis of meningitis, and interacts with human brain microvascular endothelial cells (HBMEC) to cross the blood-brain barrier. Using site-directed mutagenesis, we demonstrate that two N-glycosylation sites (NG1 and NG2) in the extracellular domain of OmpA receptor, Ecgp96 are critical for bacterial binding to HBMEC. E. coli K1 invasion assays using CHO-Lec1 cells that express truncated N-glycans, and sequential digestion of HBMEC surface N-glycans using specific glycosidases showed that GlcNAc1-4GlcNAc epitopes are sufficient for OmpA interaction with HBMEC. Lack of NG1 and NG2 sites in Ecgp96 inhibits E. coli K1 OmpA induced F-actin polymerization, phosphorylation of protein kinase C-α, and disruption of transendothelial electrical resistance required for efficient invasion of E. coli K1 in HBMEC. Furthermore, the microvessels of cortex and hippocampus of the brain sections of E. coli K1 infected mice showed increased expression of glycosylated Ecgp96. Therefore, the interface of OmpA and GlcNAc1-4GlcNAc epitope interaction would be a target for preventative strategies against E. coli K1 meningitis.

Increased levels of standardized ileal digestible threonine attenuate intestinal damage and immune responses in Escherichia coli K88+ challenged weaned piglets

This study was conducted to investigate the effects of graded levels of standardized ideal digestible threonine (SIDT) on the small intestinal morphology and immune responses of Escherichia coli K88+ challenged weaned piglets. Thirty-six crossbred (Large White×Landrace) barrows, with an initial BW of 7.34±0.55kg and weaned at 21d, were assigned to 1 of 6 treatments according to a 3 (3.7, 7.5 or 11.1g/kg dietary SIDT content)×2 (non-challenged or challenged) factorial arrangement. On d 16, half of the piglets in each SIDT treatment were orally challenged with 10mL E. coli K88+ culture (1×109CFU/mL), while the other half were orally inoculated with the same amount of phosphate buffer (PBS). On d 18 (on 2d after E. coli challenged), the pigs were killed and blood and intestinal samples were collected. The average daily gain (ADG) and feed conversion ratio (FCR) of piglets receiving the 7.5 and 11.1g/kg SIDT diets were significantly improved (P<0.01) during pre-challenge (0–16d), post-challenge (16–18d) and over the entire experiment (0–18d) compared with pigs fed the 3.7g/kg SIDT diet. E. coli K88+ challenge markedly decreased (P<0.05) ADG and FCR of piglets compared with PBS. Increasing dietary SIDT increased the relative thymus body weight of non-challenged piglets while the relative body weight of challenged piglets was not affected by SIDT. Increasing of dietary SIDT significantly increased (P<0.05) lymphocyte proliferation under challenge. Compared with pigs fed the 3.7g/kg SIDT diet, the interleukin-1β concentration significantly (P<0.05) decreased, and the interleukin-6 concentration significantly (P<0.05) increased in the jejunum of piglets fed the 7.5 and 11.1g/kg SIDT diets. It was observed that an interaction between dietary SIDT and E. coli challenge on the levels of mucosal IgA and interleukin-1β (P<0.05). Increasing SIDT increased the duodenal villus width in non-challenged piglets and there was no difference among challenged piglets. Duodenal villi height decreased (P=0.05) after E. coli challenge. Piglets receiving either the 7.5 or 11.1g/kg SIDT diets had increased villi heights and villi height to crypt depth ratio (P<0.05), and decreased crypt depth (P<0.05) in jejunum compared with the 3.7g/kg SIDT diet. Once challenged with E. coli K88+, villus height and villus height to crypt depth ratio of jejunal decreased (P<0.05). The interaction between challenge and dietary SIDT was observed in jejunal crypt depth and villus height to crypt depth ratio. Increasing dietary SIDT decreased the jejunal crypt depth and increased villus height to crypt depth ratio in non-challenged piglets. Moreover, the ileal crypt depth increased (P<0.05) and ileal villus height to crypt depth ratio decreased (P<0.05) after E. coli challenge. Collectively, these results indicate that appropriate dietary SIDT improved mucosal immune function and intestinal morphology of non-challenged pigs and also had beneficial effects in maintaining jejunal integrity and repairing villous damage caused by E. coli challenge. Our findings indicate that appropriate dietary SIDT levels need to be considered when formulating diets for weaned piglets in different physical status.

Lactulose and Lactobacillus plantarum, a potential complementary synbiotic to control postweaning colibacillosis in piglets.

The potential of a prebiotic oligosaccharide lactulose, a probiotic strain of Lactobacillus plantarum, or their synbiotic combination to control postweaning colibacillosis in pigs was evaluated using an enterotoxigenic Escherichia coli (ETEC) K88 oral challenge. Seventy-two weanlings were fed four diets: a control diet (CTR), that diet supplemented with L. plantarum (2 × 10(10) CFU · day(-1)) (LPN), that diet supplemented with 10 g · kg(-1) lactulose (LAC), or a combination of the two treatments (SYN). After 7 days, the pigs were orally challenged. Six pigs per treatment were euthanized on days 6 and 10 postchallenge (PC). Inclusion of lactulose improved the average daily gain (ADG) (P < 0.05) and increased lactobacilli (P < 0.05) and the percentage of butyric acid (P < 0.02) in the colon. An increase in the ileum villous height (P < 0.05) and a reduction of the pig major acute-phase protein (Pig-MAP) in serum (P < 0.01) were observed also. The inclusion of the probiotic increased numbers of L. plantarum bacteria in the ileum and colon (P < 0.05) and in the total lactobacilli in the colon and showed a trend to reduce diarrhea (P = 0.09). The concentrations of ammonia in ileal and colonic digesta were decreased (P < 0.05), and the villous height (P < 0.01) and number of ileal goblet cells (P < 0.05) increased, at day 10 PC. A decrease in plasmatic tumor necrosis factor alpha (TNF-α) (P < 0.01) was also seen. The positive effects of the two additives were combined in the SYN treatment, resulting in a complementary synbiotic with potential to be used to control postweaning colibacillosis.

Effect of crowding stress and Escherichia coli K88+ challenge in nursery pigs supplemented with anti-Escherichia coli K88+ probiotics1

Under commercial conditions and during production periods, pigs are generally exposed to a number of stressors that may have direct or indirect influence on their performance and general health. As a result, environmental stressors can influence the productivity as well as the onset and severity of infectious diseases. The aim of this study was to investigate the effects of crowding stress on performance and some immunological responses in piglets challenged with enterotoxigenic Escherichia coli (ETEC) K88(+) and fed diets containing anti-ETEC probiotic strains derived from E. coli in a 3-wk trial. Ninety-six piglets at 20 ± 1 d of age were randomly assigned to 6 experimental treatments with 3 pigs/pen and 5 replicates/treatment and fed a basal mash diet. To model stress, piglets were housed in 2 kinds of pens: standard floor allowance (SFA; no stress) and half standard floor allowance (HSFA; stressed). The treatments were 1) control pigs with SFA, 2) control pigs with HSFA, 3) pigs with SFA and challenged with ETEC (ESFA), 4) pigs with HSFA and challenged with ETEC (EHSFA), 5) pigs with ESFA and supplemented with a cocktail of E. coli probiotics (PSFA), and 6) pigs with EHSFA and supplemented with a cocktail of E. coli probiotics (PHSFA). After 4 d acclimatization, crowding stress was started on d 5, E. coli probiotics were given daily from d 5, and ETEC challenge was administered on d 8 and 10. Body weight and feed disappearance were determined weekly and severity of diarrhea was characterized daily. Blood samples were collected for biochemistry and inflammatory analysis and pigs were euthanized to obtain digesta for bacterial enumeration. The ADG and ADFI decreased (P < 0.05) in stressed and ETEC-challenged pigs 5 d after ETEC challenge. The ETEC population was higher in both ileal and colon digesta of stressed pigs whereas ETEC-challenged and probiotic-fed pigs had higher fecal consistency scores 96 h and 7 d after ETEC challenge. Stressed pigs had higher (P < 0.001) levels of neutrophils, neutrophil:lymphocyte ratio, albumin:globulin ratio, fibrinogen, total protein:fibrinogen ratio, and cortisol. Generally, the levels of cortisol, interleukin 6 (IL-6), and tumor necrosis factor alpha (TNF-α) differed over time among some treatment groups. In conclusion, reduced space allowance stress and ETEC challenge depressed certain aspects of performance and immunological responses and increased E. coli counts; however, probiotics feeding had little positive effects on these measures suggesting further research.

Experimental mammalian Escherichia coli K1 meningitis

Escherichia coli (E. coli) is the most common gram-negative organism causing meningitis during the neonatal period. Neonatal meningitis due to E coli K1 is a serious illness with unchanged morbidity and mortality rates for the last few decades. The mechanism involved in the pathogenesis of E. coli meningitis remains unclear. Experimental studies with animal models have given new insights into its pathophysiology during the acute phase of the disease . E. coli strain originally isolated from the Cerebrospinal fluid of a child with 20 days old was complaining acute meningitis. In the present work, we describe in detail a simple, reproducible and efficient method to induce E.coli meningitis in mice by using the three route (intrapretonium , intravenous, oral) of infection . E.coli were recovered of same characters of the original isolate used for preparing the infective dose. The histopathological changes found in the experimentally infected mice we can conclude induce meningeal thickening , neutrophiles infiltration , hemorrhages and leukocyte infiltration in brain. Key word: bacterial Meningitis , Cerebrospinal fluid, Escherichia coli k1, histopathology