Low-MFI (median fluorescence intensity) pre-transplant DSA (donor specific antibodies) leading to anamnestic antibody mediated rejection in live-related donor kidney transplantation.

"In solid organ transplantation, the compatibility between recipient and donor relies on testing prior to transplantation as a major determinant for the successful transplant outcomes. This compatibility testing depends on the detection of donor-specific antibodies (DSAs) present in the recipient. Indeed, sensitized transplant candidates are at higher risk of allograft rejection and graft loss compared to non-sensitized individuals. Most of the laboratories in India have adopted test algorithms for the appropriate risk stratification of transplants, namely: 1) donor cell-based flow-cytometric cross-match (FCXM) assay with patient's serum to detect DSAs; 2) HLA-coated beads to detect anti-HLA antibodies; and 3) complement-dependent cytotoxicity crossmatch (CDCXM) with donor cells to detect cytotoxic antibodies. In the risk stratification strategy, laboratories generally accept a DSA median fluorescence index (MFI) of 1000 MFI or lower MFI (low-MFI) as a negative value and clear the patient for the transplant. We present two cases of live-related donor kidney transplants (LDKTs) with low-MFI pre-transplant DSA values who experienced an early acute antibody-mediated rejection (ABMR) as a result of an anamnestic antibody response by DSA against HLA class II antibodies. These results were confirmed by retesting of both pre-transplant and post-transplant archived sera from patients and freshly obtained donor cells. Our examples indicate a possible ABMR in patients with low MFI pre-transplant DSA. Reclassification of low vs. high-risk may be appropriate for sensitized patients with low-MFI DSA."

Real-world data on renal transplantations from a tertiary-care hospital in North India, in context of Indian regulatory act-transplantation of human organs and tissues act (THOTA): A retrospective analysis.

INTRODUCTION: Renal transplantation is the treatment of choice for patients suffering from end stage renal disease (ESRD). Indian regulations defined under Transplantation of Human Organs and Tissues Act (THOTA), 2014 restricts organ donations to near-related living donors to curb any malpractices like 'paid donors' in living-donor kidney transplantation (LDKT). The aim of our study was to look at real-world data of donor-recipient pairs and to identify relationship of donors (with their respective patients) and the common (or uncommon) DNA profiling methods used for supporting "claimed relationship" in accordance with the regulations. MATERIAL AND METHODS: The donors were categorized and grouped into near-related donor, donors other than near-related donors, swap donors and deceased donors. Claimed relationship was confirmed, commonly by HLA typing, using SSOP method. In few cases, which were uncommon (and infrequent), autosomal DNA analysis, mitochondrial DNA analysis and Y-STR DNA analysis were performed to support the claimed relationship. Data collected included age, gender, relationship, DNA profiling test method. RESULTS: Among the 514 donor-recipient pairs evaluated, numbers of female donors out-numbered male donors. The decreasing order of relationships in near-related donor group were wife>mother>father>sister>son>brother>husband> daughter>grandmother. 11.9% of donors were in the category of donors other than near-related donors. In 97.86% cases, the claimed relationship was supported by HLA typing and in just 2.1% cases autosomal DNA analysis>mitochondrial DNA analysis> Y-STR DNA analysis, in this order, were performed to establish relationship. CONCLUSION: This study brought out gender disparity with women out-numbering men as donors. Among recipients, access to renal transplant was largely restricted to men. As far as relationship of donors to recipients was concerned, mostly near-related family members, like wife, were donors and claimed relationship was almost always (99%) was corroborated by HLA typing.

Environmental risk factors associated with the survival, persistence, and thermal tolerance of Cronobacter sakazakii during the manufacture of powdered infant formula.

Cronobacter sakazakii is an opportunistic foodborne pathogen of concern for foods having low water activity such as powdered infant formula (PIF). Its survival under desiccated stress can be attributed to its ability to adapt effectively to many different environmental stresses. Due to the high risk to neonates and its sporadic outbreaks in PIF, C. sakazakii received great attention among the scientific community, food industry and health care providers. There are many extrinsic and intrinsic factors that affect C. sakazakii survival in low-moisture foods. Moreover, short- or long-term pre-exposure to sub-lethal physiological stresses which are commonly encountered in food processing environments are reported to affect the thermal resistance of C. sakazakii. Additionally, acclimation to these stresses may render C. sakazakii resistance to antibiotics and other antimicrobial agents. This article reviews the factors and the strategies responsible for the survival and persistence of C. sakazakii in PIF. Particularly, studies focused on the influence of various factors on thermal resistance, antibiotic or antimicrobial resistance, virulence potential and stress-associated gene expression are reviewed.

Laboratory Diagnosis of ANCA-Associated Vasculitis (AAV) Using a Combination of Immunofluorescence Test (IIFT) and Line Immunoassay (LIA): Single-Centre Report From India.

INTRODUCTION: Anti-neutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is a small vessel vasculitis with insufficient epidemiological estimates in India. We aimed to determine demographic, clinical features, and laboratory diagnosis of AAV patients presenting to a large tertiary care centre in India. MATERIAL AND METHODS: 1289 patient samples were screened for ANCA by indirect immunofluorescence test (IIFT) and confirmation of ANCA target antigens was done by line immunoassay. Association between IIFT and LIA was determined in AAV. RESULTS: By IIFT, ANCA was detected in 13.0% (168 out of 1289), of which 23.8% (40/168) were positive with P-ANCA pattern, 25.0% (42/168) were positive with C-ANCA and 47.6% (80/168) showed an atypical pattern. On evaluation with a line immunoassay, 6.7% (86/1289) were positive out of which 52.3% (45/86), 41.9% (36/86), 8.8% (6/86) were positive for anti-MPO, anti-PR3, and anti-GBM respectively. In eosinophilic granulomatosis with polyangiitis (EGPA) 87.5% (7/8), and microscopic polyangiitis (MPA/RLV) 91.3% (21/23), anti-MPO was the predominantly observed antibody. In granulomatosis with polyangiitis (GPA) anti-PR3 antibody was predominant in 87.5% (28/32) cases. Out of 168 IIF positive samples 8, 32, and 23 cases of EGPA, GPA, and MPA/RLV were observed respectively. CONCLUSIONS: The primary aim of the study was to provide single-centre data to determine the laboratory diagnosis of AAV. A combination of IIFT and LIA was found to be an optimum testing strategy for the laboratory diagnosis of AAV.

Diagnostic value of different interleukins and procalcitonin in critically ill patients admitted with suspected sepsis.

BACKGROUND: : Many biomarkers have now been studied such as C-reactive Protein (CRP), procalcitonin (PCT), etc., and are widely used for the diagnosis of sepsis in clinical practice which may determine the appropriate antibiotic treatment. A flowcytometric cytokine bead array (CBA) assay has now been used to determine multiple interleukins (IL), simultaneously. The aim of this study was to determine the cytokine (IL2, IL4, IL6, IL10, TNFα, INFγ, and IL17) profiles of interleukins in plasma of sepsis patients by using multiplex Flowcytometric CBA array assay. MATERIALS AND METHOD: s: A total of 99 consecutive patients admitted with the suspected sepsis were studied. PCT concentrations were measured by using the enzyme-linked fluorescent immunoassay (ELFA) technique and flow cytometry-based BD™ CBA Cytokine Kit was used to evaluate levels of 7 cytokines [IL-2, IL-4, IL-6, IL-10, Tumour Necrosis Factor (TNF), Interferon- γ (IFN-γ), and IL-17A]. RESULTS: Microbiologically defined infection (MDI) demonstrated a positive culture report in 79/99 (79.7%) of patients. The IL6 [1873.7 (4-5000)] and IL10 [(154.7 (0-1764)] levels were significantly higher in septic patients than those in the negative MDI IL6 [901 (4-5000)] and IL10 [110.4 (4-1372)] levels. The AUROC value of IL6 [0.66 (0.53-0.79)] was found to be the highest among all followed by IL10 [0.65 (0.51-0.79)], IFNγ [0.63 (0.51-0.77)], PCT [0.61 (0.48-0.75)], and TNFα [0.55 (0.42-0.69)]. CONCLUSION: Our study suggests that that IL6 is substantially more economical and can reduce the investigation cost to half as compared with the procalcitonin assay.

Laboratory Diagnosis of ANCA-Associated Vasculitis (AAV) Using a Combination of Immunofluorescence Test (IIFT) and Line Immunoassay (LIA): Single-Centre Report From India / Diagnóstico de laboratorio de vasculitis asociada a ANCA (VAA), utilizando conjuntamente test de inmunofluorescencia (IIFT) e inmunoensayo lineal (LIA): Reporte de un único centro de la India

Introduction: Anti-neutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is a small vessel vasculitis with insufficient epidemiological estimates in India. We aimed to determine demographic, clinical features, and laboratory diagnosis of AAV patients presenting to a large tertiary care centre in India. Material and methods: 1289 patient samples were screened for ANCA by indirect immunofluorescence test (IIFT) and confirmation of ANCA target antigens was done by line immunoassay. Association between IIFT and LIA was determined in AAV. Results: By IIFT, ANCA was detected in 13.0% (168 out of 1289), of which 23.8% (40/168) were positive with P-ANCA pattern, 25.0% (42/168) were positive with C-ANCA and 47.6% (80/168) showed an atypical pattern. On evaluation with a line immunoassay, 6.7% (86/1289) were positive out of which 52.3% (45/86), 41.9% (36/86), 8.8% (6/86) were positive for anti-MPO, anti-PR3, and anti-GBM respectively. In eosinophilic granulomatosis with polyangiitis (EGPA) 87.5% (7/8), and microscopic polyangiitis (MPA/RLV) 91.3% (21/23), anti-MPO was the predominantly observed antibody. In granulomatosis with polyangiitis (GPA) anti-PR3 antibody was predominant in 87.5% (28/32) cases. Out of 168 IIF positive samples 8, 32, and 23 cases of EGPA, GPA, and MPA/RLV were observed respectively. Conclusions: The primary aim of the study was to provide single-centre data to determine the laboratory diagnosis of AAV. A combination of IIFT and LIA was found to be an optimum testing strategy for the laboratory diagnosis of AAV.(AU)

Introducción: La vasculitis asociada a anticuerpos anticitoplasma de neutrófilos –ANCA– (VAA) es una vasculitis de pequeños vasos con cálculos epidemiológicos insuficientes en India. Nuestro objetivo fue determinar las características demográficas y clínicas, y los diagnósticos de laboratorio de los pacientes con VAA que se presentaron en un gran centro de cuidados terciarios en India. Material y métodos: Se realizó un cribado de ANCA en 1.289 pacientes mediante test de inmunofluorescencia directa (IIFT), realizándose la confirmación de los antígenos diana de ANCA mediante inmunoensayo lineal. La asociación entre IIFT y LIA fue determinada en VAA. Resultados: Mediante IIFT, se detectó ANCA en el 13% de los pacientes (168 de 1.289), de los cuales, el 23,8% (40/168) fue positivo con el patrón P-ANCA, el 25% (42/168) fue positivo con C-ANCA y el 47,6% (80/168) reflejó un patrón atípico. En la evaluación con inmunoensayo lineal, el 6,7% (86/1.289) fue positivo, de los cuales, el 52,3% (45/86), 41,9% (36/86) y 8,8% (6/86) fueron positivos para anti-MPO, anti-PR3 y anti-GBM, respectivamente. En la granulomatosis eosinofílica con poliangitis (EGPA), en el 87,5% (7/8) de los casos, y en poliangitis microscópica (MPA/RLV) en el 91,3% (21/23), anti-MPO fue el anticuerpo predominantemente observado. En granulomatosis con poliangitis (GPA), el anticuerpo anti-PR3 fue predominante en el 87,5% (28/32) de los casos. De entre 168 muestras positivas de IIF, se observaron 8, 32, y 23 casos de EGPA, GPA y MPA/RLV, respectivamente. Conclusiones: El objetivo primario del estudio fue aportar los datos de un único centro para determinar el diagnóstico de laboratorio de VAA. El resultado fue que la combinación de IIFT y LIA es una estrategia óptima para el diagnóstico de laboratorio de VAA.(AU)

"Multidimensional correlation analysis of temperature and contact time on eradication of biofilms of Cronobacter sakazakii on abiotic surfaces by combination of hypochlorite and malic acid".

AIM: In the present study, malic acid in combination with sodium hypochlorite is evaluated for eradication of biofilms formed by Cronobacter sakazakii strains individually and in a cocktail on different abiotic surfaces. METHOD AND RESULTS: The biofilm formation by five strains of C. sakazakii and their cocktail culture on different substrates was studied in Tryptone Soy Broth (TSB) and reconstituted Powdered Infant Formula (PIF). Further, the effect of temperature (4, 27, 37 and 50°C) and contact time (10, 20, 30, 40, 50 and 60 min) on antibiofilm potential of test solution (0.0625 mol l-1 malic acid and 0.00004 mol l-1 sodium hypochlorite) against biofilm formed by C. sakazakii cocktail culture was investigated on these surfaces. The effect was evaluated in terms of viable cell count and biofilm texture using scanning electron microscopy (SEM). Principal Component Analysis (PCA) revealed that the maximum biofilm reduction was observed for stainless steel at 4°C after 60 min of contact whereas at 25, 37 and 50°C, maximum biofilm reduction was observed for polycarbonate. For glass and polyurethane, maximum log reductions were observed at 50°C. The SEM images revealed cell surface deformation and disruption in biofilms after treatment with the test solution. CONCLUSIONS: The antibiofilm potential was observed to be greatly affected by contact time and temperature. These results indicated that the combination of malic acid NaOCl can effectively kill and remove C. sakazakii biofilms from food contact surfaces and enteral feeding tubes.

"Multidimensional correlation analysis of temperature and contact time on eradication of biofilms of Cronobacter sakazakii on abiotic surfaces by combination of hypochlorite and malic acid".

AIM: In the present study, malic acid in combination with sodium hypochlorite is evaluated for eradication of biofilms formed by Cronobacter sakazakii strains individually and in a cocktail on different abiotic surfaces. METHOD AND RESULTS: The biofilm formation by five strains of C. sakazakii and their cocktail culture on different substrates was studied in Tryptone Soy Broth (TSB) and reconstituted Powdered Infant Formula (PIF). Further, the effect of temperature (4, 27, 37 and 50°C) and contact time (10, 20, 30, 40, 50 and 60 min) on antibiofilm potential of test solution (0.0625 mol l-1 malic acid and 0.00004 mol l-1 sodium hypochlorite) against biofilm formed by C. sakazakii cocktail culture was investigated on these surfaces. The effect was evaluated in terms of viable cell count and biofilm texture using scanning electron microscopy (SEM). Principal Component Analysis (PCA) revealed that the maximum biofilm reduction was observed for stainless steel at 4°C after 60 min of contact whereas at 25, 37 and 50°C, maximum biofilm reduction was observed for polycarbonate. For glass and polyurethane, maximum log reductions were observed at 50°C. The SEM images revealed cell surface deformation and disruption in biofilms after treatment with the test solution. CONCLUSIONS: The antibiofilm potential was observed to be greatly affected by contact time and temperature. These results indicated that the combination of malic acid NaOCl can effectively kill and remove C. sakazakii biofilms from food contact surfaces and enteral feeding tubes.

The utility of the Ion Torrent PGM next generation sequencing for analysis of the most commonly mutated genes among patients with colorectal cancer in India.

Background: The requirement for the mutation analysis for Kirsten rat sarcoma viral oncogene (KRAS) in colorectal cancer (CRC) is rapidly increasing as it is a predictive biomarker and also, its absence signifies response to anti-epidermal growth factor receptor (anti-EGFR) antibody treatment. The aim of our study was to investigate the pathological diagnosis and distribution of KRAS mutations in colorectal cancer with the use of next generation sequencing platform (Ion Torrent). Methods: A total of 56 CRC samples were tested to identify the genetic mutations, especially KRAS using the primers which included ~2800 COSMIC mutations of 50 oncogenes. Ion Torrent personal genome machine (semiconductor-based sequencing) was used for the sequencing and analysis. Along with KRAS, other 49 genes were also studied for COSMIC mutations. Results: KRAS mutation 25 (44.6%) had the highest frequency, followed by TP53 10 (17.9%) and PIK3CA mutation 4 (7.1%). Of all the KRAS mutations identified, mutations in codon 12 were most frequent followed by mutations in codon 13 and 61. The most frequent substitution was glycine to aspartate mutation in codon 12 (p.Gly12Asp) followed by glycine to valine (p.Gly12Val). Combinations of mutations were also studied. Our study revealed that seven cases (12.5%) had both KRAS and TP53 mutations (highest of all the combinations). Conclusion: The analysis of KRAS mutation frequency and its mutational subtype analysis in human CRCs by using semiconductor-based platform in routine clinical practices have been performed in Indian population. The findings were similar to earlier published reports from the Western literature.

Development of a Novel Multiplex Bead-based Assay for Measuring Autoantibodies on Flow Cytometric Platform.

BACKGROUND: Autoantibodies (AAbs) are important biomarkers for the diagnosis of Autoimmune Diseases (ADs). The detection of AAbs performed by current methods (indirect immunofluorescence test (IIFT)/Immunoblot (dot/line)/enzyme-linked immunosorbent assay ELISA) which have limitations in terms of performing multiple assays to arrive at laboratory diagnosis. We validated a novel multiplex bead-based assay (NMBA) that could quantify five common antibodies, simultaneously, on a flow-cytometry platform. METHODS: A total of five recombinant antigens (SS-A Ro60, CENP B, RNP 70, Scl 70 and Histones) were covalently coupled onto beads and tested using known positive sera (positive for AAbs) and analyzed using flow cytometer. RESULTS: The sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were obtained for each antigen, analyzed by both assays (NMBA and IIFT). It showed comparable or higher values for the NMBA. The Spearman's rank correlation coefficient (Rho) were ≥ 0.97, (P < .05), indicating that multiplexing of the five autoantigens did not alter the results obtained when antigens were tested individually. The mean intra-assay precision measured by coefficient of variation (CV) was7.56 ± 1.6% and the mean inter-assay CV was 10.03 ± 1.34%. The time taken from sample receipt to reporting of results was 90 minutes in NMBA as compared to 150 minutes of IIFT. CONCLUSION: The NMBA could quantitatively measure antibodies against five autoantigens, simultaneously in patient's sera. The assay is faster, objective, reproducible, requires low sample volume, and stable. Moreover, the flow cytometer in diagnostic laboratory settings for hematological and transplant immunology tests, can also be used for testing AAbs.

Prevalence of Clinically Significant anti-HLA Antibodies in Renal Transplant Patients: Single-center Report from North India.

INTRODUCTION: Solid organ transplantation is the preferred therapeutic modality of treatment in patients affected by terminal organ failures. Human leukocyte antigens (HLAs) plays an important role in graft survival. In many of the cases of rejection, antibodies are directed against HLA antigens expressed on the cells of the transplanted organ. Pre-transplant compatibility testing involves the use of different methodologies for the determination of anti-HLA antibodies. Luminex single-antigen bead (SAB) assay demonstrates higher sensitivity and specificity in detecting anti-HLA antibodies. The aim of this study was to determine the prevalence of anti-HLA antibodies in pre-transplant work up recipients, planned for renal transplant at a tertiary care center in India. METHODS: 1640 patients visiting tertiary care hospital for pre-transplant compatibility testing were screened with complement-dependent micro-lymphocytotoxicity crossmatch (CDC-XM) and flow cytometric crossmatch (FC-XM). The patients positive for either or both screening tests were assayed with the Luminex SAB tests in order to establish defined antigen specificity of the alloantibodies and determining donor-specific antibody (DSA). RESULTS: The two most frequent antibodies identified in each A, B, C locus of HLA class I were -A*24:03 (43.9%), A*25:01 (36.6%), B*57:01 (40.3%), B*15:12 (37.1%), C*17:01 (61.9%), C*07:01 (52.4%) and in DR, DQ DP locus in HLA class II were DRB1*09:01(40.0%), DRB1*14:04(37.6%), DQA1*04:01/DQB1*03:03 (58.4%), DQA1*05:01/DQB1*03:01 (55.1%), DPA1*02:01/DPB1*17:01 (55.0%), DPA1*02:01/DPB1*05:01 (45.0%). CONCLUSION: This study has found the prevalence and specificity of anti-HLA antibodies in north India.

Trending biocontrol strategies against Cronobacter sakazakii: A recent updated review.

Cronobacter sakazakii is an emerging foodborne pathogen, causing life-threatening infections in newborns and premature infants. Cronobacter spp. can survive under difficult processing conditions thereby contaminate the Powdered Infant Formula (PIF) during the manufacturing process. Infantile infections are associated with the consumption of contaminated PIF that was either contaminated intrinsically or extrinsically. This necessitates the development of sustainable strategies to manage the risk of Cronobacter infections. Natural methods of preservation holds promise as a viable alternative strategy to address the critical problem of emerging antimicrobial resistance and also to limit the negative effects of commonly used physico-chemical methods in food processing. The present study reviews the efficacies, potentials and developmental trends of biological antagonists and a combinatorial therapy to eliminate C. sakazakii using in vitro and in vivo methods. The mode of action of each biocontrol method has been discussed comprehensively. Most of these biocontrol agents interfere with the cell membrane integrity and its functions. However, none of the individual methods are able to eliminate the pathogen completely from the model food system i.e. reconstituted PIF. Each of the biological control strategies (agent) has its limitations in terms of their dose and method of application. A synergistic effect has been observed between the biological agent and physico-chemical treatments that may have the potential to ensure pathogen-free foods. Future research studies should evaluate the synergistic activities of these methods for their implication in infant foods as well as to understand the mechanisms of inactivation.

Laboratory Diagnosis of ANCA-Associated Vasculitis (AAV) Using a Combination of Immunofluorescence Test (IIFT) and Line Immunoassay (LIA): Single-Centre Report From India.

INTRODUCTION: Anti-neutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is a small vessel vasculitis with insufficient epidemiological estimates in India. We aimed to determine demographic, clinical features, and laboratory diagnosis of AAV patients presenting to a large tertiary care centre in India. MATERIAL AND METHODS: 1289 patient samples were screened for ANCA by indirect immunofluorescence test (IIFT) and confirmation of ANCA target antigens was done by line immunoassay. Association between IIFT and LIA was determined in AAV. RESULTS: By IIFT, ANCA was detected in 13.0% (168 out of 1289), of which 23.8% (40/168) were positive with P-ANCA pattern, 25.0% (42/168) were positive with C-ANCA and 47.6% (80/168) showed an atypical pattern. On evaluation with a line immunoassay, 6.7% (86/1289) were positive out of which 52.3% (45/86), 41.9% (36/86), 8.8% (6/86) were positive for anti-MPO, anti-PR3, and anti-GBM respectively. In eosinophilic granulomatosis with polyangiitis (EGPA) 87.5% (7/8), and microscopic polyangiitis (MPA/RLV) 91.3% (21/23), anti-MPO was the predominantly observed antibody. In granulomatosis with polyangiitis (GPA) anti-PR3 antibody was predominant in 87.5% (28/32) cases. Out of 168 IIF positive samples 8, 32, and 23 cases of EGPA, GPA, and MPA/RLV were observed respectively. CONCLUSIONS: The primary aim of the study was to provide single-centre data to determine the laboratory diagnosis of AAV. A combination of IIFT and LIA was found to be an optimum testing strategy for the laboratory diagnosis of AAV.

Prevalence of Autoimmune Diseases and Its Challenges in Diagnosis.

Autoimmune diseases (ADs) are the outcome of a malfunctioning immune system in which the immune system attacks self-antigens. These diseases are grouped into organ-specific and non-organ-specific types. Autoantibodies are important biomarkers used for confirming the diagnosis of ADs. Disease-specific autoantibodies are detected at a very early stage when typical clinical symptoms are not present in the patient, allowing prediction of the disease several years before the symptoms are visible. Diagnosis at an early stage is essential to decrease morbidity, disability, and mortality caused by ADs. Detection of autoantibodies, specific to particular phenotypes, helps to define these disorders as well as facilitate diagnosis, prognosis, and monitoring. In this review, we outline the present technologies used in autoimmune laboratories and the limitations of these methods along with future perspects of autoimmune diagnostics.

Evaluation of commercial probiotic lactic cultures against biofilm formation by Cronobacter sakazakii.

BACKGROUND/AIMS: Cronobacter sakazakii, an emergent pathogen is considered as a major concern to infants and neonates fed on reconstituted powdered infant milk formula. In conjunction with many other factors, biofilm forming capacity adds to its pathogenic potential. In view of the facts that infants are at highest risk to C. sakazakii infections, and emerging antibiotic resistance among pathogens, it is imperative to evaluate probiotic cultures for their efficacy against C. sakazakii. Therefore, pure probiotic strains were isolated from commercial probiotic products and tested for their antimicrobial and anti-biofilm activities against C. sakazakii. METHODS: A total of 6 probiotic strains were tested for their antibiotic susceptibility followed by antimicrobial activity using cell-free supernatant (CFS) against C. sakazakii. The inhibitory activity of CFS against biofilm formation by C. sakazakii was determined using standard crystal violet assay and microscopic observations. RESULTS: All the probiotic strains were sensitive to ampicillin, tetracycline, vancomycin and carbenicillin whereas most of the strains were resistant to erythromycin and novobiocin. Four of the 6 probiotic derived CFS possessed antimicrobial activity against C. sakazakii at a level of 40 µL. A higher biofilm inhibitory activity (>80%) was observed at initial stages of biofilm formation with weaker activity during longer incubation upto 48 hours (50%-60%). CONCLUSIONS: The study indicated the efficacy of isolated commercial probiotics strains as potential inhibitor of biofilm formation by C. sakazakii and could be further explored for novel bioactive molecules to limit the emerging infections of C. sakazakii.

Skimmed Milk-Based Encapsulation for Enhanced Stability and Viability of Lactobacillus gastricus BTM 7 Under Simulated Gastrointestinal Conditions.

The present study investigated skimmed milk and alginate-based encapsulation for protection of a probiotic strain, Lactobacillus gastricus BTM7 during storage and exposure to simulated gastrointestinal conditions. The investigations have revealed that coating with skimmed milk and alginate in a ratio of 1:1 resulted in highest encapsulation efficiency of 94% (p < 0.05) with approximately 1 log reduction in viable cell count and 90% release of encapsulated cells in 90 min. This formulation resulted in 5-fold higher survival of bacteria during storage at refrigeration for 21 days (p < 0.05). The encapsulation of L. gastricus BTM7 provided better protection at the pH of gastric juice or pancreatic conditions with 4- and 9-fold increase in survivability after 2 h of incubation. The principal component analysis (PCA) revealed the potential of skimmed milk supplementation to alginate (1:1) to enhance survival of probiotic strain under refrigerated storage, a process that can be safely incorporated into dairy products.

False negative single antigen bead assay: Is it always an effect of prozone?

BACKGROUND: Bead based flow cytometry and Luminex play a major role in identification of alloantibodies in renal transplant work-up. Strong sensitization events may lead to prozone phenomenon that can affect single antigen bead (SAB) assay and result in false negativity. However, this can also be due to high titer of other blocking antibodies. While methods like, heat inactivation, C1 inhibitor, Ethylene diamine tetra-acetic-acid and Dithio threitol treatment can remove interfering antibodies of complement and IgM, these methods are not optimal if false negativity is due to prozone effect, which is high titer of antibodies alone. METHODS: We hereby present a case of a highly sensitized renal transplant recipient with 64% panel reactive antibody positivity (PRA) and a subsequent negative SAB assay. This paradoxical finding hinted at SAB being a false negative result and serial dilutions were used to perform further tests. RESULTS: Serum dilutions lead to positive flow based panel reactive antibody (PRA) and flow cytometry crossmatch (FCXM), with an increasing trend in FCXM. CONCLUSIONS: In highly sensitized patients serial dilution should be considered during a transplant work-up to avoid missing any underlying antibodies. Serum dilution can be used as first option to circumvent prozone. Also, interference of other antibodies should not be labeled as prozone effect.