SCN1A rs6732655A/T polymorphism:Diagnostic and therapeutic insights for drug-resistant epilepsy

BACKGROUND A significant subset of individuals with epilepsy fails to respond to currently available antiepileptic drugs,resulting in heightened mortality rates,psychosocial challenges,and a diminished quality of life.Genetic factors,particularly within the SCN1A gene,and the pro-inflammatory cytokine response is important in intricating the drug resistance in idiopathic epilepsy cases.In this extended study,we determined the correlation of rs6732655A/T single nucleotide polymorphism to understand the causative association of SCN1A gene with epilepsy drug resistance and inflammatory response.AIM To find the correlation of SCN1A gene rs6732655A/T polymorphism with the drug-resistant epilepsy and inflammatory response.METHODS The study enrolled 100 age and sex-matched patients of both drug-resistant and drug-responsive epilepsy cases.We analysed the rs6732655A/T polymorphism to study its association and causative role in drug-resistant epilepsy cases using restriction fragment length polymorphism technique.The diagnostic performance of interleukin(IL)-1β,IL-6,and high mobility group box 1(HMGB1)protein levels was evaluated in conjunction with genotypic outcome receiver operating characteristic analysis.RESULTS AT and AA genotypes of rs6732655 SCN1A gene polymorphism were associated with higher risk of drug resistance epilepsy.Serum biomarkers IL-6,IL1βand HMGB1 demonstrated diagnostic potential,with cutoff values of 4.63 pg/mL,59.52 pg/mL and 7.99 ng/mL,respectively,offering valuable tools for epilepsy management.Moreover,specific genotypes(AA and AT)were found to be linked to the elevated levels of IL-1βand IL-6 and potentially reflecting increased oxidative stress and neuro-inflammation in drug-resistant cases supporting the previous reported outcome of high inflammatory markers response in drug resistance epilepsy.CONCLUSION SCN1A genotypes AA and AT are linked to higher drug-resistant epilepsy risk.These findings underscore the potential influence of inflammation and genetics on epilepsy treatment resistance.

Pharmacokinetic, pharmacodynamic, and neurochemical investigations of lamotrigine-pentylenetetrazole kindled mice to ascertain it as a reliable model for clinical drug-resistant epilepsy

Background:Pentylenetetrazole kindling has long been used for the screening of investigational antiseizure drugs.The presence of lamotrigine,at a very low dose,does not hamper kindling in mice;rather it modifies this epileptogenesis process into drug-resistant epilepsy.The lamotrigine-pentylenetetrazole kindled mice show resistance to lamotrigine,phenytoin,and carbamazepine.It may also be possible that other licensed antiseizure drugs,like the mentioned drugs,remain ineffective in this model;therefore,this was the subject of this study.Methods:Swiss albino mice were kindled with pentylenetetrazole for 35 days in the presence of either methylcellulose vehicle or lamotrigine(subtherapeutic dose,ie,5 mg/kg).Vehicle vs lamotrigine-kindled mice were compared in terms of(a)resistance/response toward nine antiseizure drugs applied as monotherapies and two drug combinations;(b)lamotrigine bioavailability in blood and brain;(c)blood-brain barrier integrity;and(d)amino acids and monoamines in the cerebral cortex and hippocampus.Results:Lamotrigine vs vehicle-kindled mice are similar(or not significantly different P>.05 from each other)in terms of(a)response toward drug combinations;(b)lamotrigine bioavailability;and(c)blood-brain barrier integrity except for,significantly(P<.05)reduced taurine and increased glutamate in the cerebral cortex and hippocampus.Aside from these,lamotrigine-kindled mice show significant(P<.05)resistant to lamotrigine(15 mg/kg),levetiracetam(40 mg/kg);carbamazepine(40 mg/kg),zonisamide(100 mg/kg),gabapentin(224 mg/kg),pregabalin(30 mg/kg),phenytoin(35 mg/kg),and topiramate(300 mg/kg).Conclusion:Lamotrigine-pentylenetetrazole kindling takes longer to develop(~5 weeks)in comparison to lamotrigine-amygdale(~4 weeks)and lamotriginecorneal(~2 weeks)kindling models.However,drug screening through this model may yield superior drugs with novel antiseizure mechanisms.

Young children with multidrug-resistant epilepsy and vagus nerve stimulation responding to perampanel: A case report

BACKGROUND Perampanel(PER),a third-generation antiepileptic drug,is a selective and noncompetitiveα-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor antagonist,and has been approved for the treatment of adults and adolescents with focal epilepsy.However,there are only a few studies about the efficacy and tolerability of PER in young children with multidrug-resistant epilepsy.In this case,we aimed to share our clinical experience in this group.CASE SUMMARY A 4-year-old boy without perinatal asphyxia and familial history of epilepsy began to have ictal seizures from age 14 mo,with jerky movement of four limbs and head nodding.Abnormal multifocal discharge and background activity were recorded through electroencephalography,and no pathogenic mutation was found in the whole exome sequencing for the patient and his parents.He had received valproate,levetiracetam,topiramate,oxcarbazepine,clonazepam and lacosamide sequentially at different times,but he still had frequent seizures even after vagus nerve stimulation(VNS)implantation.He was diagnosed with idiopathic multidrug-resistant epilepsy.However,his seizure frequency was significantly reduced after PER administration in a dose-dependent manner,and better cognitive behavior was observed.In addition,the adverse reactions of anger and aggression also appeared.CONCLUSION PER is effective as add-on therapy for young children with multidrug-resistant epilepsy who have previously undergone VNS implantation.

A Review of the Surgical Procedures for the Treatment of Drug-Resistant Epilepsy and Their Seizure Control Outcomes

Background: Drug-resistant epilepsy can be defined as the existence of seizures within 6 months, despite adequate therapy regimens with one or more antiepileptic drugs. Epilepsy surgery has been the standard therapy to help those patients who suffer from drug-resistant epilepsy. The goal of this surgery is to halt or reduce the intensity of seizures. This literature review aims to provide an overview of existing surgical procedures for the treatment of drug-resistant epilepsy and the degree of seizure control they provide based on available literature. Methods: Data were collected from medical journal databases, aggregators, and individual publications. The most used databases were PubMed, Medline and NCBI. Some of the keywords used to search these databases include: “drug resistant epilepsy”, “seizure control”, and “neurosurgery”. Results: Epileptic surgery is divided into resective and non-resective procedures. Studies have shown that a full resection of the epileptogenic brain area increases the probability of seizure eradication, however, the risks of postoperative impairments grow as the resection area is extended. On the other hand, patients who are unsuitable for seizure focus removal by resective surgery, such as those with multifocal seizures or overlapping epileptogenic zone with a functional cortex, may benefit from non-resective surgical options such as Vagus Nerve Stimulation and Responsive Neurostimulation. Conclusion: This literature review discusses the comprehensive treatment of epilepsy, especially the surgical treatment of drug-resistant epilepsy. The reviewed studies have shown that epilepsy surgery has promising outcomes in achieving seizure freedom/reducing seizure frequency with minimal adverse effects when performed correctly with the appropriate choice of surgical candidates.

Long-Term Impact in the Quality of Life of Patients with Drug-Resistant Epilepsy That Use Cannabidiol

Introduction: Epilepsy is considered a chronic neurological condition that manifests itself with seizures, where 30% - 40% of patients do not achieve control of their seizures despite proper management. Seizures represent a significant limitation in the patient’s daily activities and are often accompanied by emotional and relational difficulties that have a great impact on the quality of life of the patient and their families. Cannabidiol (CBD) has been found to be effective in controlling seizures and may also improve cognitive and behavioral abilities. Material and Methods: The Quality of Life of the Patient with Epilepsy (CAVE) scale was applied to patients with refractory epilepsies who use Cannabidiol (CBD) added to their base therapy, before the use of CBD and after 12 months of follow-up. The presentation of collateral effects was also evaluated. Results: Out of 34 patients, 26 (76.5%) increased their CAVE value at the end of the study and only 1 (2.9%) decreased. 19 (55.9%) improved in learning and behavior, 55.8% in the frequency of seizures and 79.4% reported a decrease in the intensity of seizures. There were other positive side effects such as improvement in alertness, language, sleep and behavior. The main side effects were mild and transitory, including drowsiness, and constipation. There was a correlation between the global perception of improvement and seizure control. Conclusions: This study shows that in the long term CBD improves the quality of life of patients with refractory epilepsies, through the control of seizures and the improvement of cognitive and behavioral functions.

Efficacy and safety of modified medium-chain triglyceride ketogenic diet in patients with drug-resistant epilepsy

Background Medium-chain triglyceride ketogenic diet(MCTKD)is previously less commonly used in China.This study was aimed to assess the efficacy and safety of the modified MCTKD in the treatment of drug-resistant epilepsy in Chinese patients.Methods Patients with drug-resistant epilepsy were enrolled to receive treatment with modified MCTKD in Guangdong Sanjiu Brain Hospital during December 2020 and September 2022.The modified MCTKD contained fat that provided 50–70%of the total energy,as well as proteins and carbohydrates that provided 20–30%and 20%of energy,respectively.The fat component was composed of 20–30%medium-chain triglycerides(MCTs)and 30–40%long-chain triglycerides.The efficacy and safety of the diet were assessed at 1,3 and 6 months.Results A total of 123 patients aged 2.5 to 65 years,were included in this study.The response rates at 1,3 and 6 months were 49.6%,43.1%,and 30.9%,respectively.The seizure freedom rates at 1,3 and 6 months were 12.2%,10.6%,and 6.5%,respectively.The retention rates at 1,3 and 6 months were 98.4%,65.0%and 33.3%respectively.Side effects occurred in 21.14%of patients,which were predominantly gastrointestinal symptoms such as abdominal pain,diarrhea,vomiting,and constipation,and most of them resolved after dietary adjustments.A total of 82 patients(66.7%)discontinued the treatment with the reason of refusing to eat(8.1%),poor efficacy(35.0%),poor compliance(4.9%),and inability to follow-up(9.8%).Only 4 patients(3.3%)withdrew the diet due to side effects.Conclusions The modified MCTKD with MCTs providing 20–30%of energy has a good safety in patients with drug-resistant epilepsy,but its effectiveness needs to be enhanced.Further modifications of MCTKD with an optimal energy ratio are required to achieve a better efficacy and safety.

Exploring multi-omics strategies for herbal treatment of drug-resistant epilepsy:a comprehensive review

Epilepsy affects approximately 70 million people worldwide.Yet scientists have a partial understanding of the disease pathophysiology due to its heterogenic nature.About 70%of cases of epilepsy are treatable with FDA-approved anti-epileptic drugs while temporal lobe epilepsy with hippocampus sclerosis(TLE-HS)is drug resistant.Numerous herbs have been noted for their potential anti-convulsant properties.Yet,due to the scarcity of experimental data,there is an urgent need to conduct thorough investigations into these herbs for their practical use in treating TLE-HS.In-depth multi-omics research is needed for targeted TLE-HS therapy,focusing on cornu ammonis subregions,dentate gyrus,and also genetically glutamate,andγ-aminobutyric acid receptors.Animal models,due to the lack of human brain tissue,enable homogeneous sample selection,comparable groups,and ample tissue for in-vitro and ex-vivo studies.Consequently,it becomes feasible to examine the effectiveness of herbs on individual brain regions at the molecular level,paving the way for the potential development of drug interventions to treat TLE-HS.

GABAergic Interneuron Cell Therapy for Drug-Resistant Epilepsy

Epilepsy,one of the most common central nervous system disorders,affects about 70 million people of all ages worldwide[1].It is characterized by hyperactive neuronal networks,resulting from imbalanced excitatory and inhibitory activity.Despite the development of multiple next-generation anti-seizure medicines,one-third of epilepsy patients are still drug-resistant[2].

The role of axon guidance molecules in the pathogenesis of epilepsy

Current treatments for epilepsy can only manage the symptoms of the condition but cannot alter the initial onset or halt the progression of the disease. Consequently, it is crucial to identify drugs that can target novel cellular and molecular mechanisms and mechanisms of action. Increasing evidence suggests that axon guidance molecules play a role in the structural and functional modifications of neural networks and that the dysregulation of these molecules is associated with epilepsy susceptibility. In this review, we discuss the essential role of axon guidance molecules in neuronal activity in patients with epilepsy as well as the impact of these molecules on synaptic plasticity and brain tissue remodeling. Furthermore, we examine the relationship between axon guidance molecules and neuroinflammation, as well as the structural changes in specific brain regions that contribute to the development of epilepsy. Ample evidence indicates that axon guidance molecules, including semaphorins and ephrins, play a fundamental role in guiding axon growth and the establishment of synaptic connections. Deviations in their expression or function can disrupt neuronal connections, ultimately leading to epileptic seizures. The remodeling of neural networks is a significant characteristic of epilepsy, with axon guidance molecules playing a role in the dynamic reorganization of neural circuits. This, in turn, affects synapse formation and elimination. Dysregulation of these molecules can upset the delicate balance between excitation and inhibition within a neural network, thereby increasing the risk of overexcitation and the development of epilepsy. Inflammatory signals can regulate the expression and function of axon guidance molecules, thus influencing axonal growth, axon orientation, and synaptic plasticity. The dysregulation of neuroinflammation can intensify neuronal dysfunction and contribute to the occurrence of epilepsy. This review delves into the mechanisms associated with the pathogenicity of axon guidance molecules in epilepsy, offering a valuable reference for the exploration of therapeutic targets and presenting a fresh perspective on treatment strategies for this condition.

Sodium channel mutation SCN1A T875M,D188V and associated dysfunction with drug resistant epilepsy

BACKGROUND The NaV1.1 sodium channel alpha subunit,encoded by SCN1A,is crucial for initiating and propagating action potentials in neurons.SCN1A gene has long been an established target in the etiology and therapy of epilepsy.However,very few studies have investigated the relevance of genetic variations in epilepsy and anti-epileptic drug resistance.AIM To investigate associations between polymorphisms,rs121917953 T/A and rs121918623 C/T,and drug resistance in epilepsy patients in the north Indian population.METHODS A total of 100 age-and sex-matched epilepsy patients(50 drug responsive and 50 drug resistant subjects)were recruited and SCN1A rs121918623 C/T*and rs121917953 T/A*polymorphisms were analyzed by the allele specific-PCR technique.χ^(2)and Fisher’s exact test were used to estimate differences between the distribution of SCN1A rs121918623 and rs121917953 gene polymorphisms among various groups.The association between distinct rs121917953 genotypes and drug resistance was analyzed using logistic regression analysis.RESULTS For the SCN1A rs121917953 T/A*(D188V)polymorphism,a significantly higher proportion of individuals with AT genotype were observed in the drug-resistant group as compared to the drug-responsive group.Additionally,a higher risk association was exhibited by AT genotype for drug resistance with an odds ratio of 3.51 and P value=0.017.For the SCN1A rs121918623 C/T*(T875M)polymorphism,no significant difference in genotype distribution was observed between the drug-resistant and drug-sensitive groups.CONCLUSION Our findings indicate that the SCN1A polymorphism D188V is associated with a higher risk of drug resistance for the AT variant as compared to the homozygous TT wild-type.Further research is needed at the functional level and in larger cohorts to determine the potential of these genes as a therapeutic target in epilepsy subjects.

Treatment of drug-resistant epilepsy with vagus nerve stimulation m review of 45 cases

Background Vagus nerve stimulation （VNS） is an alternative treatment for drug-resistant epilepsy （DRE）. The study aimed to explore the potential factors of prognosis, safety and effect of VNS treatment in patients with DRE. Methods We retrospectively examined 45 cases of DRE that received VNS treatment in our center from June 2004 to June 2010 and analyzed the parameters （age of patient receiving VNS, seizure frequency before and after VNS as well as treatment duration） by Student＇s t test, Fisher＇s exact and Mann-Whitney U tests, and multivariate Logistic regression. Results The overall response rate was 64% （29/45）, 67% （6/9） for adults and 64% （23/36） for children, with no significant difference （P=0.28）. Twenty-two cases had been in VNS therapy for over 1 year with a treatment efficacy of 73% （16/22）, whereas 23 cases had been in VNS therapy no more than 1 year with a treatment effecacy of 57% （13/23）, and has statistically significant difference （P=0.03）. The main side effect included hoarseness of voice and cough. One patient＇s device was removed due to infection. One patient＇s VNS was half-way terminated due to seizure aggravation. One patient died due to status epilepticus. Conclusions VNS is a safe and effective treatment for DRE. Duration of VNS therapy may be a crucial factor on prognosis.

Global burden of HIV-negative multidrug-and extensively drug-resistant tuberculosis based on Global Burden of Disease Study 2021

Background:Tuberculosis(TB),caused by Mycobacterium tuberculosis,remains the second leading cause of death from a single infectious disease globally and poses a significant economic and clinical burden in the world in 2022.Of particular concern is the emergence of drug-resistant TB,accounting for 15%-20%of TB deaths.It is imperative to delve into the global trends of incidence and death rate for multidrug-resistant tuberculosis(MDRTB)and extensively drug-resistant tuberculosis(XDR-TB),drawing upon the comprehensive Global Burden of Disease(GBD)2021 drug-resistant tuberculosis dataset.Methods:From the GBD 2021,data on incidence,prevalence,disability-adjusted life years(DALYs),and death of MDR-TB and XDR-TB from 1990 to 2021 were collected.We calculated the estimated annual percentage changes in age standardized incidence rate(ASIR)and age-standardized death rate(ASDR),segmented by age,sex,and socio-demographic index(SDI).The impacts of various risk factors on MDR-TB and XDR-TB were also analyzed.Results:In 2021,there were an estimated 443,680(95%uncertainty interval[UI]:259,196-766,545)incident cases of MDR-TB,and an estimated 106,818(95%UI:41,612-211,854)death cases of MDR-TB,while there were an estimated 24,036(95%UI:17,144-34,587)incident cases of XDR-TB and 7,946(95%UI:3,326-14,859)death cases of XDR-TB.The incidence and death cases of MDR-TB were lowest in high SDI regions,whereas the incidence rates of XDR-TB in high-middle SDI regions were higher than those in middle SDI and high SDI regions.Conclusion:This study reported the disease burden of drug-resistant TB from 1990 to 2021.Until 2021,drugresistant TB is still a serious problem in low SDI countries,especially for high-risk age populations with highrisk factors.Controlling drug-resistant TB requires effective control strategies and healthcare systems.

Efficacy and tolerability of ketogenic diet therapy in 55 Chinese children with drug-resistant epilepsy in Northwest China

Background:Due to the tradition of carbohydrate-rich diet,challenges exist for ketogenic diet(KD)implementation in Northwest China.This study was aimed to investigate the efficacy and tolerability of KD therapy administered with gradual initiation protocols in Chinese children with pharmacoresistant epilepsy in Northwest China.Methods:In this single-center study,55 children with drug-resistant epilepsy were enrolled from June 2013 to June 2019.The efficacy of KD,reasons for discontinuation,duration of retention and rate of adverse events were evaluated.Results:Fifty-five children aged from 2.2 months to 169.7 months were included,with a median age at KD initiation of 14.1 months,and 32 cases(58.2%)responded to the diet therapy at the last contact.The responder rates were 16.4%(9/55);36.4%(20/55),30.9%(17/55),27.3%(15/55)at 1,3,6 and 12 months,respectively.Univariate analysis indicated that the duration of epilepsy and the duration of KD therapy were predictors for KD effectiveness.Poor compliance and lack of response were main reasons for discontinuation of KD.There are a few side effects of KD,most of which were minor.Conclusions:The KD therapy with a gradual-initiation protocol is effective and tolerable for children with drug-resist-ant epilepsy in Northwest China.Early start of KD and KD duration of more than 6 months may be predictive factors for KD efficacy.

Emerging personalized virtual brain models: next-generation resection neurosurgery for drug-resistant epilepsy?

Recently,a novel workflow known as the virtual epileptic patient(VEP)has been proposed by a research team from Aix Marseille Universitéin their papers published in Lancet Neurology,Science Translational Medicine and Epilepsia.This method involves creating an individualized virtual brain model based on computational modelling,which can facilitate clinical decision-making by estimating the epileptogenic zone and performing the virtual surgery.Here,we summarize brief workflow,strengths,and limitations of VEP,as well as its performance in a retrospective study of 53 patients with drug-resistant focal epilepsy who underwent stereoelectroencephalography.A large-scale clinical trial(NCT03643016)is underway to further assess VEP,which is expected to enroll 356 patients prospectively.As supporting evidence accumulates,the clinical application of VEP has the potential to improve clinical practice,leading to better outcomes and qualities of life of patients.

Pathogenesis, diagnosis, and treatment of epilepsy: electromagnetic stimulation-mediated neuromodulation therapy and new technologies

Epilepsy is a severe,relapsing,and multifactorial neurological disorder.Studies regarding the accurate diagnosis,prognosis,and in-depth pathogenesis are crucial for the precise and effective treatment of epilepsy.The pathogenesis of epilepsy is complex and involves alterations in variables such as gene expression,protein expression,ion channel activity,energy metabolites,and gut microbiota composition.Satisfactory results are lacking for conventional treatments for epilepsy.Surgical resection of lesions,drug therapy,and non-drug interventions are mainly used in clinical practice to treat pain associated with epilepsy.Non-pharmacological treatments,such as a ketogenic diet,gene therapy for nerve regeneration,and neural regulation,are currently areas of research focus.This review provides a comprehensive overview of the pathogenesis,diagnostic methods,and treatments of epilepsy.It also elaborates on the theoretical basis,treatment modes,and effects of invasive nerve stimulation in neurotherapy,including percutaneous vagus nerve stimulation,deep brain electrical stimulation,repetitive nerve electrical stimulation,in addition to non-invasive transcranial magnetic stimulation and transcranial direct current stimulation.Numerous studies have shown that electromagnetic stimulation-mediated neuromodulation therapy can markedly improve neurological function and reduce the frequency of epileptic seizures.Additionally,many new technologies for the diagnosis and treatment of epilepsy are being explored.However,current research is mainly focused on analyzing patients’clinical manifestations and exploring relevant diagnostic and treatment methods to study the pathogenesis at a molecular level,which has led to a lack of consensus regarding the mechanisms related to the disease.

Interleukin-6 in epilepsy and its neuropsychiatric comorbidities: How to bridge the gap

There is growing evidence that interleukin(IL)-6 plays an important role in neurological and psychiatric disorders.This editorial comments on the study published in the recent issue of the World Journal of Psychiatry,which employed Mendelian randomization to identify a causal relationship between IL-6 receptor blockade and decreased epilepsy incidence.The purpose of this editorial is to highlight the dual effects of IL-6 in epilepsy and its related neuropsychiatric comorbidities.IL-6 plays a critical role in the facilitation of epileptogenesis and maintenance of epileptic seizures and is implicated in neuroinflammatory proce-sses associated with epilepsy.Furthermore,IL-6 significantly influences mood regulation and cognitive dysfunction in patients with epilepsy,highlighting its involvement in neuropsychiatric comorbidities.In summary,IL-6 is not only a pivotal factor in the pathogenesis of epilepsy but also significantly contributes to the emergence of epilepsy-related neuropsychiatric complications.Future resear-ch should prioritize elucidating the specific mechanisms by which IL-6 operates across different subtypes,stages and neuropsychiatric comorbidities of epilepsy,with the aim of developing more precise and effective interventions.Furthermore,the potential of IL-6 as a biomarker for the early diagnosis and prognosis of epile-psy warrants further investigation.

Therapeutic potential of Carum carvi in depression,memory loss,and hippocampal sclerosis reversal in temporal lobe epilepsy

Background:Epilepsy is a disease characterized by unprovoked seizures,and it affects around 70 million people worldwide.Standard treatment is ineffective in one third of all epilepsy patients.Temporal Lobe Epilepsy with Hippocampal Sclerosis(TLE-HS)is the most drug-resistant form of epilepsy,and it also impacts physical,mental,and psychological well-being of patients.Carum carvi extract has demonstrated anti-convulsant,anti-depressant,and anxiolytic properties.This study was designed to investigate if Carum carvi extract can alleviate depression and memory loss symptoms in a TLE-HS animal model.Methods:Male Sprague Dawley rats were used to create a model of TLE-HS and Carum carvi extract treatment,along with appropriate controls,was used to test the efficacy of this herbal extract in reducing the symptoms of depression and memory loss.Results:Forced swim test showed that Carum carvi extract treated TLE-HS rats resulted in significant improvement of the symptoms of depression.However,novel object recognition test showed that memory improvement did not occur.Conclusion:Depression significantly impacts the quality of life in TLE-HS patients,and this study has shown that Carum carvi extract should be explored further as an adjuvant treatment for TLE-HS patients to improve their quality of life.

Molecular Characterization of Drug-Resistant Beijing Family Isolates of Mycobacterium Tuberculosis from Tianjin,China

Objective Tuberculosis remains a severe public health issue, and the Beijing family of mycobacterium tuberculosis （M. tuberculosis） is widespread in East Asia, especially in some areas in China, like Beijing and Tianjin. This study aimed at determining the mutation patterns of drug-resistant Beijing strains of M. tuberculosis isolated from Tianjin, China. Methods A total of 822 M. tuberculosis isolates were screened for drug resistance by an absolute concentration method and the genotype was identified by PCR. 169 drug-resistant isolates of the Beijing family were analyzed for the potential mutations in the rpoB, katG, inhA promoter region and in rpsL, rrs and embB genes, which are associated with resistance to rifampin （RFP）, isoniazid （INH）, streptomycin （SM） and ethambutol （EMB） respectively by PCR and DNA sequencing. Results Fifty-eight out of 63 RFP-resistant isolates were found to carry the mutations within the 81-bp RFP resistance determining region （RRDR） of the rpoB gene and the most frequent mutations occurred at codon 531 （44.4%）, 526 （28.6%）, and 516 （7.9%） respectively. 16 mutation pattems affecting 12 different codons around the RRDR of rpoB were found. Of 116 INH-resistant isolates, 56 （48.3%） had the mutation of katG 315 （AGC→ACC） （Ser→Thr）, 3 （2.6%） carried S315N （AGC→AAC） and 27 （16.0%） had the mutation of inhA-15A→T. 84 out of 122 SM-resistant isolates （68.9%） displayed mutations at the codons 43 or 88 with AAG→AGG （Lys→Arg） of the rpsL gene and 22 （18.0%） with the mutations at positions 513A→C, 516C→T or 905 A→G in the rrs gene. Of 34 EMB-resistant isolates, 6 had mutation with M306V （ATG→GTG）, 3 with M306I （ATG→ATT）, 1 with M306I （ATG→ATA）, 1 with D328Y （GAT→TAT）, 1 with V348L （GTC→CTC）, and 1 with G406S （GGC→AGC） in the embB gene. Conelusion These novel findings extended our understanding of resistance-related mutations in the Beijing strains of M. tuberculosis and may provide a scientific basis for development of new strategies for diagnosis and control of tuberculosis in China and other countries where Beijing strains are prevalent.

Extensively drug-resistant bacteria are an independent predictive factor of mortality in 130 patients with spontaneous bacterial peritonitis or spontaneous bacteremia

AIM: To evaluate the epidemiology and outcomes of culture-positive spontaneous bacterial peritonitis (SBP) and spontaneous bacteremia (SB) in decompensated cirrhosis.METHODS: We prospectively collected clinical, laboratory characteristics, type of administered antibiotic, susceptibility and resistance of bacteria to antibiotics in one hundred thirty cases (68.5% males) with positive ascitic fluid and/or blood cultures during the period from January 1, 2012 to May 30, 2014. All patients with SBP had polymorphonuclear cell count in ascitic fluid > 250/mm3. In patients with SB a thorough study did not reveal any other cause of bacteremia. The patients were followed-up for a 30-d period following diagnosis of the infection. The final outcome of the patients was recorded in the end of follow-up and comparison among 3 groups of patients according to the pattern of drug resistance was performed.RESULTS: Gram-positive-cocci (GPC) were found in half of the cases. The most prevalent organisms in a descending order were Escherichia coli (33), Enterococcus spp (30), Streptococcus spp (25), Klebsiella pneumonia (16), S. aureus (8), Pseudomanas aeruginosa (5), other Gram-negative-bacteria (GNB) (11) and anaerobes (2). Overall, 20.8% of isolates were multidrug-resistant (MDR) and 10% extensively drug-resistant (XDR). Health-care-associated (HCA) and/or nosocomial infections were present in 100% of MDR/XDR and in 65.5% of non-DR cases. Meropenem was the empirically prescribed antibiotic in HCA/nosocomial infections showing a drug-resistance rate of 30.7% while third generation cephalosporins of 43.8%. Meropenem was ineffective on both XDR bacteria and Enterococcus faecium (E. faecium). All but one XDR were susceptible to colistin while all GPC (including E. faecium) and the 86% of GNB to tigecycline. Overall 30-d mortality was 37.7% (69.2% for XDR and 34.2% for the rest of the patients) (log rank, P = 0.015). In multivariate analysis, factors adversely affecting outcome included XDR infection (HR = 2.263, 95%CI: 1.005-5.095, P = 0.049), creatinine (HR = 1.125, 95%CI: 1.024-1.236, P = 0.015) and INR (HR =1.553, 95%CI: 1.106-2.180, P = 0.011).CONCLUSION: XDR bacteria are an independent life-threatening factor in SBP/SB. Strategies aiming at restricting antibiotic overuse and rapid identification of the responsible bacteria could help improve survival.

Molecular diagnosis and treatment of drug-resistant hepatitis B virus

Oral antiviral agents have been developed in the last two decades for the treatment of chronic hepatitis B(CHB).However,antiviral resistance remains an important challenge for long-term CHB therapy.All of the clinically available oral antiviral agents are nucleoside or nucleotide analogues that target the activity of viral reverse transcriptase(RT),and all are reported to have resistant mutations.Since the hepatitis B virus(HBV)RT,like other viral polymerases,lacks proofreading activity,the emergence of drug-resistance occurs readily under selective pressure from the administration of antiviral agents.The molecular diagnosis of drug-resistant HBV is based on sequence variations,and current diagnostic methods include sequencing,restriction fragment polymorphism analysis,and hybridization.Here,we will discuss the currently available molecular diagnosis tools,in vitro phenotypic assays for validation of drug-resistant HBV,and treatment options for drug-resistant HBV.