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Vancomycin-resistant enterococci colonization within hemodialysis population- single centre experience
No full textINTRODUCTION AND AIMS: Vancomycin-resistant Enterococci (VRE) colonization is common occurrence in hemodialysis patients, due to direct contact in closed dialysis setting, frequent hospitalizations and antibiotic use. Apart from epidemiological concern the high percentage of VRE carriers increase the risk of invasive infection outbreaks, with high morbidity and mortality in immunocompromised. The aim of this cross sectional single-centre study was to investigate the prevalence and risk factors for VRE colonization and infection among hemodialysis patients.
METHODS: Stool samples from 169 asymptomatic hemodialysis patients were obtained and cultured on enterococcosel agar with 6 μg/ml Vancomycin. Multiple regression analysis was used when studying the correlation of VRE colonization with demographic data, laboratory results, comorbidities, vascular access and previous hospitalization or antibiotic use inside of 30-day period. All patients were followed-up during 11 months, in order to asses the potential VRE infection development.
RESULTS: Coproculture of 49 patients (28.9%) showed the presence of VRE. Previous hospitalization inside 30 days, proved to be the most important risk factor for VRE development (OR 4.3, CI 1.4-10.4, p=0,014). Previous antibiotic (OR 2.2, CI 1.1-4-5, p=0.047), especially Vancomycin therapy (OR 3.5, CI 1.2-10.7, p=0.021), increased the odds of VRE colonization. We also found that VRE-colonized patients didn't have significantly higher inflammatory markers, but tended to have lower hemoglobin levels (10.2 vs 10.6 g/L, p= 0.025) with higher erythropoietin demand (5105 vs 3246 IU/week, p= 0.037). During follow-up, 11 patients (7%), of which 6 previously defined as VRE colonized, developed VRE infection. We didn't prove VRE colonization as significant risk factor for VRE infection development, but, if we observe only VRE colonized patients with central venous catheter as vascular access, they had 13.8 times higher odds of being VRE infected (OR 13.8, CI 2.7- 23.6, p=0.0014).
CONCLUSIONS: High VRE colonization rate in hemodialysis setting may increase the odds of subsequent infection among patients with central venous catheters. This finding emphasize importance of regular screening and cautious hygienic and antimicrobial practice
Sex Difference in Oxidative Stress Parameters in Spinal Cord of Rats with Experimental Autoimmune Encephalomyelitis: Relation to Neurological Deficit
No full textThe study examined (a) whether there is sex difference in spinal cord and plasma oxidative stress profiles in Dark Agouti rats immunised for experimental autoimmune encephalomyelitis (EAE), the principal experimental model of multiple sclerosis, and (b) whether there is correlation between the oxidative stress in spinal cord and neurological deficit. Regardless of rat sex, with the disease development xanthine oxidase (XO) activity and inducible nitric oxide synthase (iNOS) mRNA expression increased in spinal cord, whereas glutathione levels decreased. This was accompanied by the rise in spinal cord malondialdehyde level. On the other hand, with EAE development superoxide dismutase (SOD) activity decreased, while O-2 (-) concentration increased only in spinal cord of male rats. Consequently, SOD activity was lower, whereas O-2 (-) concentration was higher in spinal cord of male rats with clinically manifested EAE. XO activity and iNOS mRNA expression were also elevated in their spinal cord. Consistently, in the effector phase of EAE the concentration of advanced oxidation protein product (AOPP) was higher in spinal cord of male rats, which exhibit more severe neurological deficit than their female counterparts. In as much as data obtained in the experimental models could be translated to humans, the findings may be relevant for designing sex-specific antioxidant therapeutic strategies. Furthermore, the study indicated that the increased pro-oxidant-antioxidant balance in plasma may be an early indicator of EAE development. Moreover, it showed that plasma AOPP level may indicate not only actual activity of the disease, but also serve to predict severity of its course
The effect of infectious dose on humoral and cellular immune responses in Chlamydophila caviae primary ocular infection
Get PDFFollowing infection, the balance between protective immunity and immunopathology often depends on the initial infectious load. Several studies have investigated the effect of infectious dose; however, the mechanism by which infectious dose affects disease outcomes and the development of a protective immune response is not known. The aim of this study was to investigate how the infectious dose modulates the local and systemic humoral and the cellular immune responses during primary ocular chlamydial infection in the guinea pig animal model. Guinea pigs were infected by ocular instillation of a Chlamydophila caviae-containing eye solution in the conjunctival sac in three different doses: 1x10(2), 1x10(4), and 1x10(6) inclusion forming units (IFUs). Ocular pathology, chlamydial clearance, local and systemic C. caviae-specific humoral and cellular immune responses were assessed. All inocula of C. caviae significantly enhanced the local production of C. caviae-specific IgA in tears, but only guinea pigs infected with the higher doses showed significant changes in C. caviae-specific IgA levels in vaginal washes and serum. On complete resolution of infection, the low dose of C. caviae did not alter the ratio of CD4(+) and CD8(+) cells within guinea pigs' submandibular lymph node (SMLN) lymphocytes while the higher doses increased the percentages of CD4(+) and CD8(+) cells within the SMLN lymphocytes. A significant negative correlation between pathology intensity and the percentage of CD4(+) and CD8(+) cells within SMLN lymphocyte pool at selected time points post-infection was recorded for both 1x10(4), and 1x10(6) IFU infected guinea pigs. The relevance of the observed dose-dependent differences on the immune response should be further investigated in repeated ocular chlamydial infections
Lactobacillus helveticus lafti l10 supplementation modulates mucosal and humoral immunity in elite athletes: a randomized, double-blind, placebo-controlled trial
Get PDFTo test the influence of probiotic supplementation on humoral immune response, a double-blind, placebo-controlled trial was conducted. Thirty athletes (24 males and 6 females, females: (V)over dotO(2)max 38.2 +/- 4.9 ml.kg(-1).min(-1), age 23.2 +/- 1.4 years; males: (V)over dotO(2)max 57.5 +/- 9.2 ml.kg(-1).min(-1), age 24.0 +/- 2.4 years, mean +/- SD) were randomized either to the probiotic group (Lactobacillus helveticus Lafti L10, 2 x 10(10) colony-forming units) or to the placebo group. Serum and saliva samples were collected at the baseline and after 14 weeks. Total and specific antibacterial antibody levels of IgM, IgG, and IgA classes were determined for different bacteria in the serum, and in saliva, total and specific antibacterial IgA levels were examined. Total IgM was elevated in both probiotic (18%, 15-20%; mean, 90% confidence interval; p = 0.02) and placebo group (35%, 22-47%; p = 0.02), without observed differences in changes between the groups. No significant changes in IgM levels specific for tested bacteria were found. Total IgG level was constant in both groups. A significant (16%, 22.8 to 35%, p = 0.04) reduction of anti-Enterococcus faecalis IgG was noted in the placebo group, in comparison with the probiotic group. There was a substantial decrease in total IgA level in the placebo group, when measured either in serum (15%, 12-18%, p = 0.04) or in saliva (35%, -1.4 to 53%, p = 0.03). Significantly reduced levels of serum anti-lactic acid bacteria IgA antibodies in the placebo group compared with the probiotic group were detected for Lactobacillus rhamnosus LA68 (24%, 5.8-42%, p = 0.02) and for L. rhamnosus LB64 (15%, 2.7-27%, p = 0.02). Probiotic administration could have beneficial effects on systemic humoral and mucosal immune responses
Strain specificities in cellular and molecular immunopathogenic mechanisms underlying development of experimental autoimmune encephalomyelitis in aged rats
No full textTo understand strain-specificities of immune system in aged rats and their immunopathological implications, CD4+T lymphocyte-mediated neuroinflammation in experimental autoimmune encephalomyelitis (EAE) was studied in two strains. Upon immunization for EAE, 22-24-month-old Albino Oxford (AO) rats developed milder neurological deficit of prolonged duration compared with their Dark Agouti (DA) counterparts. Consistently, they exhibited: (i) diminished neuroantigen-specific CD4+T lymphocyte generation in draining lymph nodes (reflecting lower density of high-affinity IL-2 receptor complex on their surface and higher CD4+FoxP3+CD25+regulatory cell frequency); (ii) less favorable spinal cord expression of CXCL12 and CCL2, and consequently diminished infiltration of neuroantigen-specific CD4+T lymphocytes, including highly pathogenic IL-17+IFN-gamma+ones, and inflammatory monocytes into the spinal cord and (iii) subsequently impaired CD4+T lymphocyte reactivation/survival and differentiation into highly pathogenic IL-17+cells (reflecting downregulated expression of IL-1 beta, IL-6 and IL-23/p19). On the other hand, when the neurological deficit reached maximum/plateau, in AO rat spinal cord was found lower CD4+FoxP3+CD25+ cell frequency followed by higher frequency of IL-10-producing CD8+T cells, which most likely also belong to regulatory T lymphocytes. Thus, the altered relation between regulatory T cell and effector CD4+T cell subsets was linked with persistence of mild neuroinflammation in AO rat EAE model. (C) 2017 Elsevier B.V. All rights reserved
Evaluation of Food Allergy in Children by Skin Prick Tests with Commercial Extracts and Fresh Foods, Specific IgE and, Open Oral Food Challenge: Our Five Years Experience in Food Allergy Work-up
No full textIgE-mediated food allergy affects 6-8% of children. Our study aimed to define the correlations between the results obtained with skin prick tests (SPTs) using commercial extracts and fresh foods, and the correlations between these result and those obtained with specific IgE (sIgE) and/or challenge. Children aged from 2 months to 6 years were recruited prospectively. Overall 571 children were positive to one food. In all children we performed SPT using commercial extracts of suspected food and fresh foods and sIgE. If SPT and sIgE test results did not correspond to the history, we performed open oral food challenge. Sensitivity of SPT with commercial extracts for all tested food was poor (3-35%), while sensitivity of fresh food skin prick tests (FFSPT) was excellent (50-100%), and showed correlation with open oral food challenge (p lt 0.001). Our results suggest that fresh food extracts are more effective in detecting sensitization and with levels of sIgE greater than class 3 could predict clinical reactivity, without the need for potentially hazardous food challenges
Immunogenic Properties of Lactobacillus plantarum Producing Surface-Displayed Mycobacterium tuberculosis Antigens
Get PDFTuberculosis (TB) remains among the most deadly diseases in the world. The only available vaccine against tuberculosis is the bacille Calmette-Guerin (BCG) vaccine, which does not ensure full protection in adults. There is a global urgency for the development of an effective vaccine for preventing disease transmission, and it requires novel approaches. We are exploring the use of lactic acid bacteria (LAB) as a vector for antigen delivery to mucosal sites. Here, we demonstrate the successful expression and surface display of a Mycobacterium tuberculosis fusion antigen (comprising Ag85B and ESAT-6, referred to as AgE6) on Lactobacillus plantarum. The AgE6 fusion antigen was targeted to the bacterial surface using two different anchors, a lipoprotein anchor directing the protein to the cell membrane and a covalent cell wall anchor. AgE6-producing L. plantarum strains using each of the two anchors induced antigen-specific proliferative responses in lymphocytes purified from TB-positive donors. Similarly, both strains induced immune responses in mice after nasal or oral immunization. The impact of the anchoring strategies was reflected in dissimilarities in the immune responses generated by the two L. plantarum strains in vivo. The present study comprises an initial step toward the development of L. plantarum as a vector for M. tuberculosis antigen delivery. IMPORTANCE This work presents the development of Lactobacillus plantarum as a candidate mucosal vaccine against tuberculosis. Tuberculosis remains one of the top infectious diseases worldwide, and the only available vaccine, bacille Calmette-Guerin (BCG), fails to protect adults and adolescents. Direct antigen delivery to mucosal sites is a promising strategy in tuberculosis vaccine development, and lactic acid bacteria potentially provide easy, safe, and low-cost delivery vehicles for mucosal immunization. We have engineered L. plantarum strains to produce a Mycobacterium tuberculosis fusion antigen and to anchor this antigen to the bacterial cell wall or to the cell membrane. The recombinant strains elicited proliferative antigenspecific T-cell responses in white blood cells from tuberculosis-positive humans and induced specific immune responses after nasal and oral administrations in mice
Imunomodulatorna aktivnost rekombinanatne izoforme lektina iz banane u fiziološkim i patološkim uslovima u debelom crevu miševa BALB/c soja
Get PDFBanana lectin (BanLec) is primarily isolated from the fruit of banana (Musa paradisiac). It is glucose / mannose-specific lectin that belongs to the jackalin superfamily of lectins. There are several naturally occurring BanLec isoforms. Nowadays BanLec can also be produced by recombinant technology (rBanLec). rBanLec possesses structural and functional characteristics that highly resemble those reported for its natural counterparts. As most plant lectins, (r)BanLec is resistant to denaturation/proteolytic cleavage in the gastrointestinal tract. It has been reported that rBanLec attaches specifically to the mucosal surface of small intestine and passes into subepithelial compartment. (r)BanLec has been recognized as a potential immunomodulator. It has been shown that (r)BanLec modulates functional characteristics of lymphocytes but the effects of (r)BanLec stimulation in other immune cells are not yet elucidated. The aim of this study was to investigate immunomodulatory / immunostimulatory activity of rBanLec in the colon of BALB/c mice. This aim was accomplished through evaluation of the impact of rBanLec stimulation on 1) functional characteristics of antigen presenting cells (APC) isolated from BALB/c mice 2) local immune system in the large intestine of healthy BALB/c mice, and 3) the course of TNBS-induced experimental colitis in BALB/c mice. Peritoneal macrophages and spleen dendritic cells (DC) isolated from BALB/c mice were used in vitro for the evaluation of rBanLec influence on functional characteristics of APC. Generally, it is shown that rBanLec in a dose-dependent manner modulated the functional characteristics of APCs. By using resident (RMs) and thioglycollate-elicited (TGMs) peritoneal macrophages, it has been shown that effects of rBanLec stimulation depend on its concentration but also on the functional status of macrophages. Obtained results have clearly shown that rBanLec, in a positive dosedependent manner, promotes pro-inflammatory phenotype with BALB/c RMs (enhancement of NO and IL-12, reduction of arginase activity and IL-4 secretion) while, in the same manner, it tends to skew BALB/c TGMs towards anti-inflammatory profile (reduction of NO and IL-12 production, enhancement of arginase activity and IL-4 secretion). The dose-dependent changes in production of TGF-β by peritoneal macrophages also depended on their functional status: rBanLec stimulated the production of TGF-β by RMs in a negative dose-dependent manner, while in TGMs production of TGF-β positively correlated to the rBanLec concentration. The activity of myeloperoxidase (MPO) and productions of TNF-α and IL-10 were enhanced upon rBanLec stimulation in a positive dose-dependent manner with both RMs and TGMs. Further, it was shown that interactions of rBanLec with TLR2 and TLR4 / CD14 are important for initiations of the production of pro-inflammatory mediators by peritoneal macrophages irrespective to their functional status. rBanLec also stimulated in a specific dose-dependent manner the secretion of effector cytokines IFN-γ and IL-4 (negative dose dependent manner) and regulatory cytokine IL-10 (positive dose-dependent manner) by spleen DCs...Lektin banane (BanLec) pripada podgrupi lektina koji vezuju glukozu ili manoza- u okviru familije lektina sličnih žakalinu. U plodu banane, koji predstavlja prirodni izvor BanLec-a, javlja se u više izoformi, a može se proizvesti i rekombinantnom DNK tehnologijom. Rekombinantna izoforma BanLec-a (rBanLec) je po svojim strukturnim karakteristikama i specifičnosti vrlo slična prirodnim izoformama. Kao i većina biljnih lektina, (r)BanLec ne podleže brzo denaturaciji / razgradnji u uslovima digestivnog trakta, a pokazano je da se vezuje za epitel tankog creva i postepeno prolazi u subepitelni prostor. Danas je poznato da BanLec, nezavisno od izoforme, ima imunomodulatorni potencijal. Dosadašnja istraživanja su se dominantno bavila uticajem (r)BanLec-a na funkcionalne karakteristike limfocita i pokazano je da stimulacije određene ćelijske populacije prirodnim i rekombinantnom izoformom kvalitativno imaju isti ishod. Uticaj (r)BanLec-a na funkcionalne karakteristike drugih ćelija imunskog sistema nije detaljno analiziran. Cilj ove doktorske teze je da se kroz ispitivanja (1) modulatornog dejstva rBanLeca na funkcionalne karakteristike antigen-prezentujućih ćelija (APĆ) BALB/c miša, (2) imunomodulatornog dejstva rBanLec-a u debelom crevu BALB/c miša u fiziološkim uslovima, i (3) efekata profilaktičke i terapijske primene rBanLec-a u modelu TNBS-om indukovanog kolitisa kod BALB/c miša, dobije uvid u imunomodulatorni efekat rBanLec-a na imunski sistem u mukozi debelog creva miševa BALB/c soja pod specifičnim uslovima. Koristeći peritonealne makrofage i dendritske ćelije slezine (DĆ) kao in vitro model sisteme, pokazano je da rBanLec dozno-zavisno moduliše funkcionalne karakteristike APĆ BALB/c miševa. Analiza uticaja rBanLec stimulacije na karakteristike rezidentnih (RM) i tioglikolatom-indukovanh (TGM) peritonealnh makrofaga, pokazala je da ishod stimulacije određene ćelijske populacije nije jednoznačan već zavisi od njihovog funkcionalnog stanja. rBanLec na pozitivan dozno-zavisan način pospešuje proinflamatorni kapacitet RM (povećanje produkcije NO i IL-12 i smanjenje aktivnosti arginaze i sekrecije IL-4), a na isti način smanjuje proinflamatorni kapacitet TGM (smanjenje produkcije NO i IL-12 i povećanje aktivnosti arginaze i sekrecije IL-4). Uticaj rBanLec-a na produkciju TGF-β kod peritonealnih makrofaga takođe zavisi od funkcionalnog stanja makrofaga (kod RM, rBanLec negativno dozno-zavisan, a kod TGM pozitivno dozno-zavisno utiče na produkciju TGF-β). I kod RM i kod TGM, rBanLec na pozitivan dozno-zavisan način podstiče aktivnost mijeloperoksidaze (MPO), produkciju TNF-α i IL-10. Za stimulaciju produkcije proinflamatornih medijatora, nezavisno od funkcionalnog stanja makrofaga, značajno je vezivanje rBanLec-a za TLR2 i TLR4 / CD14. rBanLec utiče na sekreciju efektorskih citokina IFN-γ i IL-4 (negativno dozno-zavisno) i regulatornog citokina IL-10 (pozitivno dozno-zavisno) od strane DĆ slezine. rBanLec TLR2-posredovana stimulacija DĆ slezine nije ključna za promene u ekspresiji Ifn-γ i Il-4..
Hypoallergenic acid-sensitive modification preserves major mugwort allergen fold and delivers full repertoire of MHC class II-binding peptides during endolysosomal degradation
Get PDFModified allergens are a safer and more efficient alternative to natural allergens for specific immunotherapy. As the modification of an allergen can diminish its immunogenicity due to the alteration of T-cell epitopes, in this paper we study the effects of a reversible chemical modification of Art v 1, the main allergen of mugwort pollen, on its allergenicity and immunogenicity. Modification of Art v 1 by cis-aconitylation into a polyanionic derivative (CAA) did not result in any significant structural alteration. However, IgE-binding epitopes on CAA were blocked, resulting in a reduced IgE-binding and basophil activation. Both proteins induced proliferation of CD3(+)CD4(+) T-cells in mugwort-allergic patients, but only unmodified allergens increased IL-4, IL-5 and IL-10 production. Rabbit and mouse anti-CAA antibodies exhibited cross-reactivity with native allergens and blocked human IgE-binding to Art v 1. Degradation of CAA by lysosomal fraction enzymes resulted in a similar set of peptides, harboring MHC class II-binding peptides, as unmodified proteins. Thus, cis-aconitylation modified Art v 1 had a significantly reduced allergenicity, whereas its immunogenicity was completely preserved. Acid-environment-responsive modification, which releases a full repertoire of native allergen epitopes within a particular site, can be considered a smart drug delivery system, which is able to deliver a therapeutically-effective dose in a controlled manner, and minimizes adverse side effects
Active Lactobacillus rhamnosus LA68 or Lactobacillus plantarum WCFS1 administration positively influences liver fatty acid composition in mice on a HFD regime
No full textWestern life style, and high calorie diet in particular is causing major health problems such as insulin resistance, hepatic steatosis and heart disease in the modern age. High fat diet (HFD) induces similar changes in mice, such as increased body weight, hypercholesterolemia and accumulation of triglycerides in the liver. These changes can be ameliorated by the administration of some Lactobacillus species. The focus of this study was to analyze the fatty acid content of liver, heart and brain tissues of mice fed HFD and administered with either Lactobacillus plantarum WCFS1 or Lactobacillus rhamnosus LA68, and to analyze the fatty acid content of these organs after a two months washout period. The fatty acid composition of mouse liver tissue changed significantly due to probiotic administration during a 12 weeks HFD regime and active Lactobacillus administration had a slightly reversing effect toward the standard mouse diet group, but after the washout period these changes disappeared. The fatty acid composition of the heart and brain tissues was significantly changed in the HFD regime but probiotic administration had no significant influence on the fatty acid profile of these two organs. Upon the 8 weeks washout period the only remaining beneficial effect was the significantly lower mouse weight in the supplemented groups compared to the HFD group