Guillain-Barré Syndrome-related campylobacter jejuni in Bangladesh: ganglioside mimicry and cross-reactive antibodies

BACKGROUND: <br/> Campylobacter jejuni is the predominant antecedent infection in Guillain-Barré syndrome (GBS). Molecular mimicry and cross-reactive immune responses to C. jejuni lipo-oligosaccharides (LOS) precipitate the development of GBS, although this mechanism has not been established in patients from developing countries. We determined the carbohydrate mimicry between C. jejuni LOS and gangliosides, and the cross-reactive antibody response in patients with GBS in Bangladesh.<br/> METHODOLOGY:<br/> Sera from 97 GBS patients, and 120 neurological and family controls were tested for antibody reactivity against LOS from C. jejuni isolates from GBS patients in Bangladesh (BD-07, BD-39, BD-10, BD-67 and BD-94) by enzyme-linked immunosorbent assay (ELISA). Cross-reactivity to LOS was determined by ELISA. The LOS outer core structures of C. jejuni strains associated with GBS/MFS were determined by mass spectrometry.<br/> PRINCIPLE FINDINGS:<br/> IgG antibodies to LOS from C. jejuni BD-07, BD-39, BD-10, and BD-67 IgG antibodies were found in serum from 56%, 58%, 14% and 15% of GBS patients respectively, as compared to very low frequency (<3%) in controls (p<0.001). Monoclonal antibodies specific for GM1 and GD1a reacted strongly with LOS from the C. jejuni strains (BD-07 and BD-39). Mass spectrometry analysis confirmed the presence of GM1 and GD1a carbohydrate mimics in the LOS from C. jejuni BD-07 and BD-39. Both BD-10 and BD-67 express the same LOS outer core, which appears to be a novel structure displaying GA2 and GD3 mimicry. Up to 90-100% of serum reactivity to gangliosides in two patients (DK-07 and DK-39) was inhibited by 50 µg/ml of LOS from the autologous C. jejuni isolates. However, patient DK-07 developed an anti-GD1a immune response while patient DK-39 developed an anti-GM1 immune response.<br/> CONCLUSION:<br/> Carbohydrate mimicry between C. jejuni LOS and gangliosides, and cross-reactive serum antibody precipitate the majority of GBS cases in Bangladesh

Guillain-Barré syndrome following varicella-zoster virus infection

We describe the frequency, clinical features, and electrophysiological and immunological phenotypes of Guillain-Barré Syndrome (GBS) patients treated at a single institution in Bangladesh who had preceding chicken pox (primary Varicella-zoster virus [VZV] infection) within 4 weeks of GBS onset. A literature review of GBS cases preceding VZV infection is also provided. Diagnosis of GBS was based on the National Institute of Neurological Disorders and Stroke criteria for GBS. Serum anti-VZV IgM and IgG antibodies were quantified by indirect chemiluminescence immunoassay (CLIA); anti-Campylobacter jejuni IgG, IgM, and IgA antibodies and anti-ganglioside GM1 IgM and IgG antibodies, by enzyme-linked immunosorbent assays. Neurophysiologic subtypes were categorized following the Hadden criteria. Of 536 patients with GBS, 7 (1.3%) had chicken pox within 4 weeks before GBS onset. Four of the seven cases were male (age range, 23 to 40 years old). All seven patients were bed-bound, six had sensory symptoms, and three required mechanical ventilation for respiratory failure. All seven patients had CSF albuminocytologic dissociation and evidence of demyelination in nerve conduction studies. Anti-VZV IgM antibodies were present and anti-GM1 and anti-Campylobacter jejuni lipo-oligosaccharides (LOS) were negative in all cases. All patients had excellent outcome at 1 year (able to run). A systematic literature review of GBS cases related to VZV revealed 39 previously reported patients with comparable clinical presentations and outcomes, of which 36 had neurophysiologic evidence of demyelination. VZV infection is associated with the demyelinating subtype of GBS, clearly distinct from the axonal form of GBS that predominate in countries like Bangladesh

Microarray screening of Guillain-Barré syndrome sera for antibodies to glycolipid complexes

__Objective:__ To characterize the patterns of autoantibodies to glycolipid complexes in a large cohort of Guillain-Barré syndrome (GBS) and control samples collected in Bangladesh using a newly developed microarray technique. __Methods:__ Twelve commonly studied glycolipids and lipids, plus their 66 possible heteromeric complexes, totaling 78 antigens, were applied to polyvinylidene fluoride-coated slides using a microarray printer. Arrays were probed with 266 GBS and 579 control sera (2 mL per serum, diluted 1/50) and bound immunoglobulin G detected with secondary antibody. Scanned arrays were subjected to statistical analyses. __Results:__ Measuring antibodies to single targets was 9% less sensitive than to heteromeric complex targets (49.2% vs 58.3%) without significantly affecting specificity (83.9% 85.0%). The optimal screening protocol for GBS sera comprised a panel of 10 glycolipids (4 single glycolipids GM1, GA1, GD1a, GQ1b, and their 6 heteromeric complexes), resulting in an overall assay sensitivity of 64.3% and specificity of 77.1%. Notable heteromeric targets were GM1:GD1a, GM1:GQ1b, and GA1:GD1a, in which exclusive binding to the complex was observed. __Conclusions:__ Rationalizing the screening protocol to capture the enormous diversity of glycolipid complexes can be achieved by miniaturizing the screening platform to a microarray platform, and applying simple bioinformatics to determine optimal sensitivity and specificity of the targets. Glycolipid complexes are an important category of glycolipid antigens in autoimmune neuropathy cases that require specific analytical and bioinformatics methods for optimal detection

An Architecture of IoT Service Delegation and Resource Allocation Based on Collaboration between Fog and Cloud Computing

Despite the wide utilization of cloud computing (e.g., services, applications, and resources), some of the services, applications, and smart devices are not able to fully benefit from this attractive cloud computing paradigm due to the following issues: (1) smart devices might be lacking in their capacity (e.g., processing, memory, storage, battery, and resource allocation), (2) they might be lacking in their network resources, and (3) the high network latency to centralized server in cloud might not be efficient for delay-sensitive application, services, and resource allocations requests. Fog computing is promising paradigm that can extend cloud resources to edge of network, solving the abovementioned issue. As a result, in this work, we propose an architecture of IoT service delegation and resource allocation based on collaboration between fog and cloud computing. We provide new algorithm that is decision rules of linearized decision tree based on three conditions (services size, completion time, and VMs capacity) for managing and delegating user request in order to balance workload. Moreover, we propose algorithm to allocate resources to meet service level agreement (SLA) and quality of services (QoS) as well as optimizing big data distribution in fog and cloud computing. Our simulation result shows that our proposed approach can efficiently balance workload, improve resource allocation efficiently, optimize big data distribution, and show better performance than other existing methods

Small volume plasma exchange for Guillain-Barré syndrome in resource poor settings: A safety and feasibility study

Background: In Bangladesh, most patients with Guillain-Barré syndrome (GBS) cannot afford standard treatment with intravenous immunoglobulin (IVIG) or a standard plasma exchange (PE) course, which partly explains the high rate of mortality and residual disability associated with GBS in this country. Small volume plasma exchange (SVPE) is an affordable and potentially effective alternative form of plasma exchange. SVPE is the repeated removal of small volumes of supernatant plasma over several days via sedimentation of patient whole blood. The aim of this study is to define the clinical feasibility and safety of SVPE in patients with GBS in resource poor settings. Methods: A total of 20 adult patients with GBS will be enrolled for SVPE at a single center in Bangladesh. Six daily sessions of whole blood sedimentation and plasma removal will be performed in all patients with GBS with a target to remove an overall volume of at least 8 liters (L) of plasma over a total of 8 days. Serious adverse events (SAE) are defined as the number of patients developing severe sepsis associated with the central venous catheter or deep venous thrombosis in the limb where the catheter is placed for SVPE. Based upon a predictive success rate of 75%, the SVPE procedure will be considered safe if less than 5 of 20 SVPE-treated GBS patients have a SAE. The procedure will be considered feasible if 8 L of plasma can be removed in at le

Small volume plasma exchange for Guillain-Barré syndrome in resource poor settings: A safety and feasibility study

Background: In Bangladesh, most patients with Guillain-Barré syndrome (GBS) cannot afford standard treatment with intravenous immunoglobulin (IVIG) or a standard plasma exchange (PE) course, which partly explains the high rate of mortality and residual disability associated with GBS in this country. Small volume plasma exchange (SVPE) is an affordable and potentially effective alternative form of plasma exchange. SVPE is the repeated removal of small volumes of supernatant plasma over several days via sedimentation of patient whole blood. The aim of this study is to define the clinical feasibility and safety of SVPE in patients with GBS in resource poor settings. Methods: A total of 20 adult patients with GBS will be enrolled for SVPE at a single center in Bangladesh. Six daily sessions of whole blood sedimentation and plasma removal will be performed in all patients with GBS with a target to remove an overall volume of at least 8 liters (L) of plasma over a total of 8 days. Serious adverse events (SAE) are defined as the number of patients developing severe sepsis associated with the central venous catheter or deep venous thrombosis in the limb where the catheter is placed for SVPE. Based upon a predictive success rate of 75%

CRISPR-CAS diversity in clinical salmonella enterica serovar typhi isolates from South Asian countries

Typhoid fever, caused by Salmonella enterica serovar Typhi (S. Typhi), is a global health concern and its treatment is problematic due to the rise in antimicrobial resistance (AMR). Rapid detection of patients infected with AMR positive S. Typhi is, therefore, crucial to prevent further spreading. Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated genes (CRISPR-Cas), is an adaptive immune system that initially was used for typing purposes. Later, it was discovered to play a role in defense against phages and plasmids, including ones that carry AMR genes, and, at present, it is being explored for its usage in diagnostics. Despite the availability of whole-genome sequences (WGS), very few studied the CRISPR-Cas system of S. Typhi, let alone in typing purposes or relation to AMR. In the present study, we analyzed the CRISPR-Cas system of S. Typhi using WGS data of 1059 isolates obtained from Bangladesh, India, Nepal, and Pakistan in combination with demographic data and AMR status. Our results reveal that the S. Typhi CRISPR loci can be classified into two groups: A (evidence level >2) and B (evidence level ≤2), in which we identified a total of 47 unique spacers and 15 unique direct repeats. Further analysis of the identified spacers and repeats demonstrated specific patterns that harbored significant associations with genotype, demographic characteristics, and AMR status, thus raising the possibility of their usage as biomarkers. Potential spacer targets were identified and, interestingly, the phage-targeting spacers belonged to the group-A and plasmid-targeting spacers to the group-B CRISPR loci. Further analyses of the spacer targets led to the identification of an S. Typhi protospacer adjacent motif (PAM) sequence, TTTCA/T. New cas-genes known as DinG, DEDDh, and WYL were also discovered in the S. Typhi genome. However, a specific variant of the WYL gene was only identified in the extensively drug-resistant (XDR) lineage from Pakistan and ciprofloxacin-resistant lineage from Bangladesh. From this work, we conclude that there are strong correlations between variations identified in the S. Typhi CRISPR-Cas system and endemic AMR positive S. Typhi isolates

Tracking the emergence of azithromycin resistance in multiple genotypes of typhoidal salmonella

The rising prevalence of antimicrobial resistance in Salmonella enterica serovars Typhi and Paratyphi A, causative agents of typhoid and paratyphoid, have led to fears of untreatable infections. Of specific concern is the emerging resistance against azithromycin, the only remaining oral drug to treat extensively drug resistant (XDR) typhoid. Since the first report of azithromycin resistance from Bangladesh in 2019, cases have been reported from Nepal, India, and Pakistan. The genetic basis of this resistance is a single point mutation in the efflux pump AcrB (R717Q/L). Here, we report 38 additional cases of azithromycin-resistant (AzmR) Salmonella Typhi and Paratyphi A isolated in Bangladesh between 2016 and 2018. Using genomic analysis of 56 AzmR isolates from South Asia with AcrB-R717Q/L, we confirm that this mutation has spontaneously emerged in different Salmonella Typhi and Paratyphi A geno-types. The largest cluster of AzmR Typhi belonged to genotype 4.3.1.1; Bayesian analysis predicts the mutation to have emerged sometime in 2010. A travel-related Typhi isolate with AcrB-R717Q belonging to 4.3.1.1 was isolated in the United Kingdom, increasing fears of global spread. For real-time detection of AcrB-R717Q/L, we developed an extraction-free, rapid, and low-cost mismatch amplification mutation assay (MAMA). Validation of MAMA using 113 AzmR and non-AzmR isolates yielded >98% specificity and sensitivity versus phenotypic and whole-genome sequencing assays currently used for azithromycin resistance detection

Small volume plasma exchange for Guillain-Barré syndrome in resource-limited settings: A phase II safety and feasibility study

Objective To assess the safety and feasibility of small volume plasma exchange (SVPE) for patients with Guillain-Barré syndrome (GBS). Design Non-randomised, single-arm, interventional trial. Setting National Institute of Neurosciences and Hospital, Dhaka, Bangladesh. Participants Twenty adult (>18 years) patients with GBS presented within 2 weeks of onset of weakness who were unable to walk unaided for more than 10 m. Interventions SVPE involves blood cell sedimentation in a blood bag and removal of supernatant plasma after blood cells are retransfused. This procedure was repeated three to six times a day, for eight consecutive days. Fresh frozen plasma (FFP) and normal saline were used as replacement fluid. Outcome measures Serious adverse events (SAEs) were defined as severe sepsis and deep venous thrombosis related to the central venous catheter (CVC) used during SVPE. SVPE was considered safe if less than 5/20 patients experienced an SAE, and feasible if 8 L plasma could be removed within 8 days in at least 15/20 patients. Results Median patient age 33 years (IQR 23-46; range 18-55); 13 (65%) were male. Median Medical Research Council (MRC) sum score was 20 (IQR 0-29; range 0-36); three (15%) patients required mechanical ventilation. One patient developed SAE (severe sepsis, possibly related to CVC). The median plasma volume exchanged was 140 mL/kg (range 110-175) and removal of 8 L plasma was possible in 15 (75%) patients. Patients received a median 1 g/kg IgG via FFP although a substantial proportion of IgG was probably removed again by the SVPE sessions. GBS disability score improved by at least one grade in 14 (70%) patients 4 weeks after SVPE started. No patients died. Conclusion SVPE seems a safe and feasible alternative treatment to standard plasma exchange (PE) or intravenous immunoglobulin (IVIg) for GBS; further studies of clinical efficacy in low-income and middle-income countries are warranted. Trial registration number NCT02780570

Salmonella enterica Serovar Typhi in Bangladesh: Exploration of Genomic Diversity and Antimicrobial Resistance

Typhoid fever, caused by Salmonella enterica serovar Typhi, is a global public health concern due to increasing antimicrobial resistance (AMR). Characterization of S Typhi genomes for AMR and the evolution of different lineages, especially in countries where typhoid fever is endemic such as Bangladesh, will help public health professionals to better design and implement appropriate preventive measures. We studied whole-genome sequences (WGS) of 536 S Typhi isolates collected in Bangladesh during 1999 to 2013 and compared those sequences with data from a recent outbreak in Pakistan reported previously by E. J. Klemm, S. Shakoor, A. J. Page, F. N. Qamar, et al. (mBio 9:e00105-18, 2018, https://doi.org/10.1128/mBio.00105-18), and a laboratory surveillance in Nepal reported previously by C. D. Britto, Z. A. Dyson, S. Duchene, M. J. Carter, et al. [PLoS Negl. Trop. Dis. 12(4):e0006408, 2018, https://doi.org/10.1371/journal.pntd.0006408]. WGS had high sensitivity and specificity for prediction of ampicillin, chloramphenicol, co-trimoxazole, and ceftriaxone AMR phenotypes but needs further impr