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Lactic acid bacteria are the predominant group within meat products, whose metabolites such as bacteriocins and peptidoglycan hydrolases inhibit pathogenic or spoilage bacteria. Fermented meat products, as a salami, is a good source to analyze the viable microbiota, due to these products present a low risk to consumer health. The aim of this work was to identify the lactic acid bacteria with broad antibacterial activity present in salami, purify the protein responsible for this activity, achieve antagonistic spectrum and perform the biochemical characterization. Five strains from salami were selected, isolated and identified by 16S rRNA gene sequencing. The antimicrobial activity was evaluated by antagonism assay and zymography, using spoilage microorganisms commonly found in meat products. The strain that showed a broad antibacterial activity was Latilactobacillus sakei and the antibacterial activity was given by a protein with 75-kDa of molecular mass, identified by LC/MALDI-TOF/TOF. The sequence analysis showed 67% of identity with a N-acetylmuramoyl-L-alanine amidase protein with five non-identical LysM domains. The purified protein showed an optimal pH of 8.0 and heat resistance at 80 °C for 10 min. L. sakei strain displayed antibacterial activity against Gram-negative and Gram-positive spoilage microorganisms. The results of this study provide the information to use Latilactobacillus sakei as a starter culture which will provide the necessary metabolites to combat undesirable microorganisms. Additionally, the conditions and properties for the best application and use of the antibacterial protein produced by this strain. This protein may have a potential use in the food industry as a new antibacterial agent.

Assuntos

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INTRODUCTION: Pretransplant donor-specific HLA alloantibodies detected with the Single Antigen Bead (SAB) assay reflect an increased risk for acute antibody-mediated rejection (AMR). We herein report the incidence of both acute AMR and acute cellular rejection (ACR) during the first year posttransplantation, in a cohort of kidney transplant recipients (KTR) of deceased donor (DD) grafts, according to their DSA status. Pretransplant DSA do not preclude DD-KT in negative CDC-XM recipients at our center. PATIENTS AND METHODS: 246 KT were performed at our center between 01/2012 and 12/2015 and 100 KTR obtained from a DD were analyzed; 24% harbored DSA by SAB assay, MFI values >500 were considered positive. All recipients received thymoglobulin induction and generic tacrolimus-based maintenance therapy. Graft biopsies were performed by protocol on months 3 and 12 as well as per indication. The incidence of AMR and ACR was correlated with the existence of pretransplant DSA. RESULTS: Overall, 34% of patients developed an acute rejection episode, 54.2% in the DSA group versus 27.6% in the non-DSA group (p=0.032), and most of these events were detected as subclinical conditions in protocol biopsies. AMR events developed in 33.3% and 19.7% (p=0.176) in the DSA and the non-DSA groups, respectively. ACR events were found in 16.6% and 6.6% (p=0.127) in the DSA and non-DSA groups, respectively. Graft function was similar between groups at the end of the 1st year posttransplant and no immunological graft loss occurred. CONCLUSION: Despite the use of depleting induction therapy and adequate tacrolimus trough levels along with MMF and steroids, a high rate of rejection events was observed during the first year post-transplantation.

Assuntos

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The complement-binding capacity of anti-HLA antibodies (HLAabs) is recognized as a key pathogenic factor. The aim of this study is to describe the patient characteristics associated to the presence of C1q+ as well as those of the Abs per se when associated to C1q binding. METHODOLOGY: This is a cross-sectional, observational, descriptive study of patients with previous sensitizing factors and awaiting a kidney transplant (KT). We determined anti-HLA antibodies and their C1q binding capacity with the C1q assay. RESULTS: Among the 55 included patients, 26 (47.2%) had at least one C1q+ anti-HLAab. A previous transplant history, a greater number of HLAabs, a greater % of class I or class II PRA, the average MFI of all HLAabs, the MFI of the dominant HLAab and the HLAab antigenic specificities against HLA-B, -C and -DQ, all proved to be risk factors associated to the presence of C1q binding HLAabs (C1q+). In the total population, were detected 1268 HLAabs, 230 (18.1%) of which were C1q+. On multivariate analysis, both HLAabs against the HLA-DQ antigenic specificity (OR 9.82 95% CI 5.4-17.6, p<0.001) and the MFI documented by LABScreen®SAB (OR 1.2% CI 1.22-1.3, p<0.001), proved to be risk factors. CONCLUSION: Anti-HLA-DQ antibodies and the MFI (LABScreen®SAB) are highly and independently related to the C1q-binding capacity of HLA antibodies.

Assuntos

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The aim of the present study was to describe the association of positive flow cross match (FXM) and C1q-SAB. Methods. In this observational, cross-sectional, and comparative study, patients included had negative AHG-CDC-XM and donor specific antibodies (DSA) and were tested with FXM. All pretransplant sera were tested with C1q-SAB assay. Results. A total of 50 donor/recipient evaluations were conducted; half of them had at least one C1q+ Ab (n = 26, 52%). Ten patients (20.0%) had DSA C1q+ Ab. Twenty-five (50%) FXMs were positive. Factors associated with a positive FXM were the presence of C1q+ Ab (DSA C1q+ Ab: OR 27, 2.80-259.56, P = 0.004, and no DSA C1q+ Ab: OR 5, 1.27-19.68, P = 0.021) and the DSA LABScreen-SAB MFI (OR 1.26, 95% CI 1.06-1.49, P = 0.007). The cutoff point of immunodominant LABScreen SAB DSA-MFI with the greatest sensitivity and specificity to predict FXM was 2,300 (sensitivity: 72% and specificity: 75%). For FXM prediction, DSA C1q+ Ab was the most specific (95.8%, 85-100) and the combination of DSA-MFI > 2,300 and C1q+ Ab was the most sensitive (92.0%, 79.3-100). Conclusions. C1q+ Ab and LABScreen SAB DSA-MFI were significantly associated with FXM. DSA C1q+ Ab was highly specific but with low sensitivity.

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AIM: To identify the frequency of exposure to sensitizing factors and evaluate the risk ascribable to each sensitizing factor generating HLAabs measured by Luminex. METHODS: This is a retrospective cohort study that included 502 transplanted patients and 51 patients on the waiting list for a deceased donor graft. Patients were divided into 4 groups according to the %PRA: 0%, 1 to 19%, 20 to 49% and ≥50%. The OR attributable to each sensitizing factor or combination were calculated. RESULTS: Of the total 553 subjects, 53.5% were male, with an average age 35.42±12.96years. 69.1% were exposed to one or more sensitizing factors; 44.8% had %PRA class I≥1 and 38.9% had %PRA class II≥1. Independently or combined, sensitizing factors persist as a risk factor for the development of a %PRA >1%, >20% or >50%. After multivariate analysis, the three sensitizing factors remained significantly associated to HLAab development. CONCLUSIONS: In spite of using a most sensitive technique such as Luminex to measure the %PRA, a clear association persists between exposure to sensitizing factors and a high %PRA. The risk increases after exposure to more than one sensitizing factor.

Assuntos

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In complement dependent cytotoxicity crossmatch negative renal transplant candidates with human leukocyte antigen donor-specific antibodies (DSA), both the presence of DSA C1q+ and the dominant DSA fluorescence were significantly associated with a positive flow cytometry crossmatch (FXM+). The C1q+ assay was highly specific, but had low sensitivity when predicting FXM+, so the clinical significance of a FXM+ in the absence of DSA C1q+ remains to be clarified in future studies.

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BACKGROUND: Studies of Mycobacterium bovis BCG strains used in different countries and vaccination programs show clear variations in the genomes and immune protective properties of BCG strains. The aim of this study was to characterise the genomic and immune proteomic profile of the BCG 1931 strain used in Mexico. RESULTS: BCG Mexico 1931 has a circular chromosome of 4,350,386 bp with a G+C content and numbers of genes and pseudogenes similar to those of BCG Tokyo and BCG Pasteur. BCG Mexico 1931 lacks Region of Difference 1 (RD1), RD2 and N-RD18 and one copy of IS6110, indicating that BCG Mexico 1931 belongs to DU2 group IV within the BCG vaccine genealogy. In addition, this strain contains three new RDs, which are 53 (RDMex01), 655 (RDMex02) and 2,847 bp (REDMex03) long, and 55 single-nucleotide polymorphisms representing non-synonymous mutations compared to BCG Pasteur and BCG Tokyo. In a comparative proteomic analysis, the BCG Mexico 1931, Danish, Phipps and Tokyo strains showed 812, 794, 791 and 701 protein spots, respectively. The same analysis showed that BCG Mexico 1931 shares 62% of its protein spots with the BCG Danish strain, 61% with the BCG Phipps strain and only 48% with the BCG Tokyo strain. Thirty-nine reactive spots were detected in BCG Mexico 1931 using sera from subjects with active tuberculosis infections and positive tuberculin skin tests. CONCLUSIONS: BCG Mexico 1931 has a smaller genome than the BCG Pasteur and BCG Tokyo strains. Two specific deletions in BCG Mexico 1931 are described (RDMex02 and RDMex03). The loss of RDMex02 (fadD23) is associated with enhanced macrophage binding and RDMex03 contains genes that may be involved in regulatory pathways. We also describe new antigenic proteins for the first time.

Assuntos