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Three compounds were identified from the ethanolic extract of Anemarrhena asphodeloides Bunge (A. asphodeloides) plant using silica gel chromatography. Their structures were confirmed by NMR and MS...

Tomato is one of the most important vegetables cultivated in Vietnam. Besides its regular consumption as a vegetable, a new demand for using tomato as a decorative plant on special occasions was identified in recent years. This study aimed to characterize new tomato accessions on their desirable morphological traits to select potential materials for further breeding programs of ornamental tomato varieties in Vietnam. Twenty-four heirloom tomato genotypes were evaluated on 19 morphological traits. Based on the describing system for tomato developed by the International Plant Genetic Resources Institute (IPGRI, 1996), significant variation was assessed in both qualitative and quantitative traits related to fruit morphology. The results of principle component analysis indicated that three main principle components explained over 60% of the total phenotypic variation. The five traits of fruit size, fruit shoulder shape, fruit cross-sectional shape, number of locules, and shape of the pistil scar were recommended as important traits for clustering tomato genotypes in this study. In addition, the 24 genotypes were classified at the coefficient of 0.39 into six different clusters. Finally, six interesting accessions, AU66, AU67, AU68, AU73, AU79, and AU83 (with strange fruit colors and shapes), were selected as potential materials for further breeding programs of ornamental tomato in Vietnam.

Background: The DNA barcoding is currently an effective and widely used tool that enables rapid and accurate identification of plant species. Methods: DNA barcoding of 9 chloroplast genes (rbcL, matK, trnH-psbA, accD-psaI, ndhA, psbE-petL, Rpl32-trnL, trnW-psaJ, trnSGCU-trnGGCC) were used to provide the theoretical basis for species identification, genetic diversity analysis of lotus population collected in Thua Thien Hue province, Vietnam. Universal primers were used and sequence products were analyzed using the MEGA X program. Result: The results showed that high levels of haplotype diversity (Hd), ranging from 0.618-0.869 and low levels of nucleotide diversity (Pi), ranging from 0.180 × 10-3-3.280 × 10-3 base on a total of nine gene regions of chloroplast genome. The neutrality tests show an excess of rare nucleotide position variations in individuals’ white lotus and derived haplotypes recent expansion. While the evolution of the individuals in the pink lotus may have to decrease. The phylogenetic analyses indicated that combined sequences were not insufficient to make a difference to the DNA barcoding in the individual’s lotus of the N. nucifera species this is in the study. The standardized and accurate barcode information of lotus is provided for researchers. It lays the foundation for the conservation, evaluation, innovative utilization and protection of Nelumbonaceae germplasm resources.

In this report, two new steroidal glycosides were isolated and determined from n-butanol fraction of A.asphodeloides. The structures were confirmed in comparison with the spectral data of known compounds by using different spectroscopic analysis approaches including 1D & 2D-NMR techniques and HRMS. The anti-proliferation screening against cancer cell lines A549 and HeLa indicated that compound 1 exhibited good inhibitory activities with IC50 values of 0.79 and 0.55 µg/mL, respectively.

The diarrheal disease cholera is still a burden for populations in developing countries with poor sanitation. To develop effective vaccines and prevention strategies against Vibrio cholerae, we must understand the initial steps of infection leading to the colonization of the small intestine., Intestinal mucus is the first line of defense against intestinal pathogens. It acts as a physical barrier between epithelial tissues and the lumen that enteropathogens must overcome to establish a successful infection. We investigated the motile behavior of two Vibrio cholerae strains (El Tor C6706 and Classical O395) in mucus using single-cell tracking in unprocessed porcine intestinal mucus. We determined that V. cholerae can penetrate mucus using flagellar motility and that alkaline pH increases swimming speed and, consequently, improves mucus penetration. Microrheological measurements indicate that changes in pH between 6 and 8 (the physiological range for the human small intestine) had little effect on the viscoelastic properties of mucus. Finally, we determined that acidic pH promotes surface attachment by activating the mannose-sensitive hemagglutinin (MshA) pilus in V. cholerae El Tor C6706 without a measurable change in the total cellular concentration of the secondary messenger cyclic dimeric GMP (c-di-GMP). Overall, our results support the hypothesis that pH is an important factor affecting the motile behavior of V. cholerae and its ability to penetrate mucus. Therefore, changes in pH along the human small intestine may play a role in determining the preferred site for V. cholerae during infection. IMPORTANCE The diarrheal disease cholera is still a burden for populations in developing countries with poor sanitation. To develop effective vaccines and prevention strategies against Vibrio cholerae, we must understand the initial steps of infection leading to the colonization of the small intestine. To infect the host and deliver the cholera toxin, V. cholerae has to penetrate the mucus layer protecting the intestinal tissues. However, the interaction of V. cholerae with intestinal mucus has not been extensively investigated. In this report, we demonstrated using single-cell tracking that V. cholerae can penetrate intestinal mucus using flagellar motility. In addition, we observed that alkaline pH improves the ability of V. cholerae to penetrate mucus. This finding has important implications for understanding the dynamics of infection, because pH varies significantly along the small intestine, between individuals, and between species. Blocking mucus penetration by interfering with flagellar motility in V. cholerae, reinforcing the mucosa, controlling intestinal pH, or manipulating the intestinal microbiome will offer new strategies to fight cholera.

Background: DNA barcoding is a relatively new method of identifying plant species using short sequences of chloroplast DNA. Although there is a large number of studies using barcoding on various plant species, there are no such studies in the genus Nelumbo. Methods: Three chloroplast DNA regions (rbcL, matK, trnH-psbA) were tested for their suitability as DNA barcoding regions of thirty three lotus samples which were collected in Thua Thien Hue province, Vietnam. Universal primers were used and sequenced products were analyzed using Minimum Evolution method in the MEGA 7.0 program.Result: We did not observe high variability in nucleotide sequences within the rbcL region (0.135%). White Nelumbo, while, the most encoding matK (8.013%) and variable trnH-psbA (with different number of repeating regions TAAAA) intergenic regions was the most useful for Nelumbo barcoding. Individual application of the studied regions did not provide the expected results. None of the regions used in the study allowed the division of white and pink lotus varieties of N. nucifera specie according to the adopted classification of the genus Nelumbo. The results confirm that the use of matK, rbcL and trnH-psbA or combine all three regions together is insufficient for DNA barcoding in white and pink lotus varieties of N. nucifera specie and better discrimination within the genus Nelumbo. Our results also indicate the necessity of using a different region. All of the new sequences have been deposited in GeneBank under the following accession numbers: rbcL (MN011708 to MN068956); matK (MN011719 to MN068978) and trnH-psbA (MN011730 to MN086252).

In this study, homogeneous titanate tubular (TNT) and diatom/TNT composites (D/TNT) were prepared by a facile hydrothermal method. The crystalline structure and morphology of the synthesised samples were studied by X-ray diffractometry (XRD), Raman spectroscopy, Transmission Electron Microscopy (TEM). Furthermore, the photocatalytic activity for degradation of methylene blue (MB) was investigated under sunlight irradiation. The results showed that the MB degradation by D/TNT was higher than bare TNT. Optical properties of the synthesized materials with enhanced photocatalytic activity could be explained through both UV-vis diffuse absorption and photoluminescence emission measurement. These results indicated that there was bandgap narrowing and longer carrier lifetime in the composite sample.

Background: Lotus is an important aquatic plant with great economic value, not only as an ornamental flower but also as a source of herbal medicine. In general, lotus is usually propagated through the rhizome or tuber but the normal propagation rate is very low and it often depends on the quality of water environment and the weather conditions where it is grown. Lotus propagation by tissue culture has many predominant advantages compared with the traditional propagation methods. The current study aims to study the in vitro propagation of Hue’s Red Lotus, a famous local lotus in Hue city, Vietnam. Methods: Fresh mature seeds of Red lotus (23 to 25 days old) were used as initial materials for in vitro propagation. Experiments are carried out to assess sterilization ability by HgCl2, 0.1% and determine the appropriate formula for shoot regeneration, multiple shoot clumps induction, root induction of multiple shoot clumps and acclimatization. Result: The optimum formula for seeds of Vinh Thanh Red Lotus is to sterilize surface of seeds by 70% ethanol for 30 seconds and then HgCl2 0.1% for 16 minutes. The samples were cultured on MS (Murashige Skoog) medium supplemented without plant growth regulators for in vitro shoot regeneration. MS medium added with 0.5 mg/L BAP gave the highest multiplication rate (5.60 shoots per explant) and good quality shoots. Adding 0.5 mg/L NAA in rooting medium provided the highest rooting effect and good root quality (18.17 roots/shoot clumps). The survival rate of transplanting plants was 40% on mud medium which were soaked for one week in 2g/L KMnO4 after two weeks in the greenhouse.

Hydrangeas are very popular shrubs thanks to their attractive, colorful flowers and foliage. Recently, they have been commercialized for cut-flower production. For mass propagation of this plant species using plant tissue culture, it is necessary to study the effects of culture medium and culture conditions on in vitro plant growth. In the first experiment, in vitro hydrangea shoots were cultured for 56 days on Murashige and Skoog (MS) media containing one among five different types of macro-elements. The half concentration of NH4NO3 on MS macro-elements significantly increased fresh and dry weights of hydrangea shoots in comparison with other treatments. The number of roots of in vitro plants in this treatment were the highest, resulting in better absorption of culture nutrient. Cross sections of the shoot base on day 14th showed that reducing only NH4NO3 on the MS medium enhanced the formation of adventitious roots. The experiment on culture conditions showed that photoautotrophic condition was suitable for the in vitro growth of hydrangea. Plants grown under photoautotrophic (PA) condition had increased fresh weight (341.39 mg/plt), increased dry weight (31.03 mg/plt) with leaf area (7.76 cm2) significantly greater than those grown under photomixotrophic (PM) condition (259.53 mg/plt, 38.22 mg/plt and 4.73 cm2 respectively). In addition, the net photosynthetic rate (Pn) of plants under PA condition was statistically higher and increased over the culture period while Pn of plants under PM condition remained constant. This study demonstrated that MS salts with half concentration of NH4NO3 and photoautotrophic culture method were appropriate for in vitro growth of hydrangea.

Trehalose synthase (TreS, EC 2.4.1.245) is a potential catalyst for synthesis of trehalose, an important natural disaccharide. In this study, the treS gene of Pseudomonas putida (VTCC 12263) was cloned into pHT01 plasmid at BamHI-XbaI position, expressed in Bacillus subtilis (B. subtilis) 1012, and characterized. The recombinant TreS had molecular weight of 68 kDa when fused with 8xHis tag at the C-terminus. catalyzed conversion of maltose to trehalose in optimal conditions had specific activity of 1.664 U/g. Expression of TreS was highest when B. subtilis 1012 harboring pHT01-treS was cultured in TB medium at 30 oC, induced with 1.0 mM IPTG when OD600 reached 0.8 and harvested after 10 hours of induction. The recombinant TreS purified by Ni-sepharose chromatography had specific activity of 41.700 U/g and formed a single band on Western blot with monoclonal antibody against His-tag. The recombinant TreS had optimal activity at 37 oC in 100 mM pH 7.4 PBS and 300 mM maltose. It was inhibited by NaCl, KCl and MgCl2 (retaining 45% or 75% specific activity in buffer containing 5 mM KCl or 5 mM MgCl2, respectively) and stimulated by imidazol (with specific activity increasing by 30–200%).

Outbreaks of emerging coronaviruses in the past two decades and the current pandemic of a novel coronavirus (SARS-CoV-2) that emerged in China highlight the importance of this viral family as a zoonotic public health threat. To gain a better understanding of coronavirus presence and diversity in wildlife at wildlife-human interfaces in three southern provinces in Viet Nam 2013-2014, we used consensus Polymerase Chain Reactions to detect coronavirus sequences. In comparison to previous studies, we observed high proportions of positive samples among field rats (34.0%, 239/702) destined for human consumption and insectivorous bats in guano farms (74.8%, 234/313) adjacent to human dwellings. Most notably among field rats, the odds of coronavirus RNA detection significantly increased along the supply chain from field rats sold by traders (reference group; 20.7% positivity, 39/188) by a factor of 2.2 for field rats sold in large markets (32.0%, 116/363) and 10.0 for field rats sold and served in restaurants (55.6%, 84/151). Coronaviruses were detected in the majority of wildlife farms (60.7%, 17/28) and in the Malayan porcupines (6.0%, 20/331) and bamboo rats (6.3%, 6/96) that are farmed. We identified six known coronaviruses in bats and rodents, clustered in threeCoronaviridaegenera, including theAlpha-,Beta-, andGammacoronaviruses. Our analysis also suggested either mixing of animal excreta in the environment or interspecies transmission of coronaviruses, as both bat and avian coronaviruses were detected in rodent feces in the trade. The mixing of multiple coronaviruses, and their apparent amplification along the wildlife supply chain into restaurants, suggests maximal risk for end consumers and likely underpins the mechanisms of zoonotic spillover to people.

Bacteria within a swarm move characteristically in packs, displaying an intricate swirling motion in which hundreds of dynamic rafts continuously form and dissociate as the swarm colonizes an increasing expanse of territory. The demonstrated property of E. coli to reduce its tumble bias and hence increase its run duration during swarming is expected to maintain and promote side-by-side alignment and cohesion within the bacterial packs. In this study, we observed a similar low tumble bias in five different bacterial species, both Gram positive and Gram negative, each inhabiting a unique habitat and posing unique problems to our health. The unanimous display of an altered run-tumble bias in swarms of all species examined in this investigation suggests that this behavioral adaptation is crucial for swarming., Many bacteria use flagellum-driven motility to swarm or move collectively over a surface terrain. Bacterial adaptations for swarming can include cell elongation, hyperflagellation, recruitment of special stator proteins, and surfactant secretion, among others. We recently demonstrated another swarming adaptation in Escherichia coli, wherein the chemotaxis pathway is remodeled to decrease tumble bias (increase run durations), with running speeds increased as well. We show here that the modification of motility parameters during swarming is not unique to E. coli but is shared by a diverse group of bacteria we examined—Proteus mirabilis, Serratia marcescens, Salmonella enterica, Bacillus subtilis, and Pseudomonas aeruginosa—suggesting that increasing run durations and speeds are a cornerstone of swarming.

To examine the transmission dynamics of Mycobacterium tuberculosis (Mtb) isolated from tuberculosis patients in Ho Chi Minh City, Vietnam, we sequenced the whole genomes of 1,635 isolates and compared these with 3,144 isolates from elsewhere. The data identify an underlying burden of disease caused by the endemic Mtb lineage 1 associated with the activation of long-term latent infection, and a threefold higher burden associated with the more recently introduced Beijing lineage and lineage 4 Mtb strains. We find that Beijing lineage Mtb is frequently transferred between Vietnam and other countries, and detect higher levels of transmission of Beijing lineage strains within this host population than the endemic lineage 1 Mtb. Screening for parallel evolution of Beijing lineage-associated SNPs in other Mtb lineages as a signal of positive selection, we identify an alteration in the ESX-5 type VII-secreted protein EsxW, which could potentially contribute to the enhanced transmission of Beijing lineage Mtb in Vietnamese and other host populations.

Medicago truncatula seeds were cultured and developed in Thua Thien Hue province, Vietnam, and they were used as materials for cloning a DHDPS gene with the encoding of the isozyme dihydrodipicolinate synthase (DHDPS) as well as optimizing the culture conditions for having the highest DHDPS gene expression in Escherichia coli BL21 StarTM (DE3) cells. The results revealed that the coding region of the DHDPS gene from M. truncatula was 100% similar with M. truncatula 4-hydroxy-tetrahydrodipicolinate synthase 2 (DHDPS2) submitted in NCBI (accession number: XM_013589555.2), coding for a long polypeptide of 307 amino acid with the molecular mass of about 33495 Da (Protein ID: XP_013445009.1). The DHDPS gene was successfully expressed in the Escherichia coli BL21 StarTM (DE3) cells with a pET200 / D-TOPO vector, and this produced the DHDPS2 protein with molecular masses of approximately 33.87 kDa (»33.5 kDa of DHDPS2 and 3.7 kDa of fusion fragment of pET 200/D-TOPO vector). The effects of the six different culture mediums of LB, SOB, SOC, YJ, HSG and TB, the induction times of 2h, 4h, 6h, 8h, 10h and 12h, and the inducer concentrations of 0.2 mM; 0.5 mM; 0.7 mM; 1.0 mM; 1.2 mM and 1.5 mM IPTG (Isopropyl â-D-1-thiogalactopyranoside) were also investigated for the purpose of optimising the expression of DHDPS2 in E. coli cells, and it was found that strong expression of recombinant DHDPS2 protein in E. coli. BL21 (DE3) cells occurred on the TB, HSG and YJ culture mediums after 8 hours with 0.2 mM inducible IPTG (BioRad).

The fundamental motile behavior of E. coli is a random walk, where straight “runs” are punctuated by “tumbles.” This behavior, conferred by the chemotaxis signaling system, is used to track chemical gradients in liquid. Our study results show that when migrating collectively on surfaces, E. coli modifies its chemosensory physiology to decrease its tumble bias (and hence to increase run durations) by post-transcriptional changes that alter the levels of a key signaling protein. We speculate that the low tumble bias may contribute to the observed Lévy walk (LW) trajectories within the swarm, where run durations have a power law distribution. In animals, LW patterns are hypothesized to maximize searches in unpredictable environments. Swarming bacteria face several challenges while moving collectively over a surface—maintaining cohesion, overcoming constraints imposed by a physical substrate, searching for nutrients as a group, and surviving lethal levels of antimicrobials. The altered chemosensory behavior that we describe in this report may help with these challenges., Many flagellated bacteria “swarm” over a solid surface as a dense consortium. In different bacteria, swarming is facilitated by several alterations such as those corresponding to increased flagellum numbers, special stator proteins, or secreted surfactants. We report here a change in the chemosensory physiology of swarming Escherichia coli which alters its normal “run tumble” bias. E. coli bacteria taken from a swarm exhibit more highly extended runs (low tumble bias) and higher speeds than E. coli bacteria swimming individually in a liquid medium. The stability of the signaling protein CheZ is higher in swarmers, consistent with the observed elevation of CheZ levels and with the low tumble bias. We show that the tumble bias displayed by wild-type swarmers is the optimal bias for maximizing swarm expansion. In assays performed in liquid, swarm cells have reduced chemotactic performance. This behavior is specific to swarming, is not specific to growth on surfaces, and persists for a generation. Therefore, the chemotaxis signaling pathway is reprogrammed for swarming.

Introduction: Ricinus communis Linn. (Castor oil plant) is a monotypic species of Ricinus genus (Euphorbiaceae) and widely distributed in all tropical countries. Phytochemical data of this plant are scarce. As part of ongoing research on a survey of Vietnamese medicinal plants, the investigation of this plant was performed. The isolation and structural determination of five phenolic compounds isolated from the leaves of R. communis Linn. growing in Binh Phuoc province were addressed. Method: The dried power of R. communis Linn. leaves was macerated in ethanol to afford the crude extract, which was then separated by liquid-liquid extraction with n-hexane, chloroform, and ethyl acetate, respectively to obtain the corresponding extracts. These extracts were applied to multiple silica gel column chromatography and thin-layer chromatography to yield five compounds. Their chemical structures were determined by spectroscopic methods and by comparison of NMR data with literature values. Antioxidant evaluation of 1 was carried out using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) free radical scavenging assay. Results: Five phenolic compounds, including one coumarinolignan cleomiscosin A (1), two flavonol glycosides kaempferol-3-O-β-D-glucopyranoside (2) and kaempferol-3-O-β-D-xylopyranoside (3), and two aromatic acids gallic acid (4) and vanillic acid (5) were identified. Conclusion: Compound 1 was determined for the first time in Ricinus genus and exhibited weak DPPH radical scavenging activity with an SC50 value of 403.23 μg/mL.

Tuberculosis (TB) is a leading cause of death from infectious disease and the global burden is now higher than at any point in history. Despite coordinated efforts to control TB transmission, the factors contributing to its successful spread remain poorly understood. Vietnam is identified as one of 30 high burden countries for TB and MDR-TB with an incidence of 137 TB cases per 100,000 individuals in 2015. Recent phylogenomic analyses of the causative agent Mycobacterium tuberculosis (Mtb) in other high-prevalence regions have provided insights into the complex processes underlying TB transmission. Here we examine the transmission dynamics of Mtb isolated from TB patients in Ho Chi Minh City (HCMC), Vietnam via whole genome analysis of 1,635 isolates and comparison with 3,085 isolates from other locations. The genomic data reveal an underlying burden of disease caused by endemic Mtb Lineage 1 associated with activation of long-term latent infection, on top of which is overlaid a three-fold higher burden associated with introduction of exotic Lineage 2 and 4 Mtb strains. We identify frequent transfer of Beijing lineage Mtb into the country, which are associated with higher levels of transmission in this host population than endemic Lineage 1 Mtb. We identify a mutation in the secreted protein EsxW in Beijing strains that also appears to be under positive selection in other Mtb lineages, which could potentially contribute to the enhanced transmission of the Beijing lineage in Vietnamese and other host populations.

Ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), which is a member of the ubiquitin carboxyl-terminal hydrolase (UCH) family, is highly expressed in neurons. In vitro, UCH- L1 exhibits both ubiquitin hydrolase and ligase activity. Many studies have suggested that UCH-L1 is involved in the pathogenesis of Parkinson's disease and some different human cancer diseases, but its role in a living system is still unclear. Recently, Drosophila melanogaster has been shown to be a compatible model for studying human diseases. To investigate the role of UCH-L1 in a living system, the UCH-L1 homologous protein in Drosophila melanogaster (dUCH) is used for analyzing the role of the protein's function in transgenic Drosophila. Here, we used DNA molecular techniques to clone, express, and purify dUCH protein from Escherichia coli. The purified dUCH protein was injected into a rabbit to produce an anti-dUCH antibody, which was shown to have high specificity and sensitivity to the dUCH protein. The affinity of the antibody is 1:320,000 at 7.81 ng/μL antigen concentration. The 1:40,000 dilution-produced antibodies can detect antigen at a low concentration of 0.98 ng/μL. Success in producing this antibody provides good material for further experiments in the study of the role of UCH-L1 by a Drosophila model.

We used large sequence polymorphisms to determine the genotypes of 397 isolates of Mycobacterium tuberculosis from human immunodeficiency virus-uninfected Vietnamese adults with pulmonary ( n = 235) or meningeal ( n = 162) tuberculosis. We compared the pretreatment radiographic appearances of pulmonary tuberculosis and the presentation, response to treatment, and outcome of tuberculous meningitis between the genotypes. Multivariate analysis identified variables independently associated with genotype and outcome. A higher proportion of adults with pulmonary tuberculosis caused by the Euro-American genotype had consolidation on chest X-ray than was the case with disease caused by other genotypes ( P = 0.006). Multivariate analysis revealed that meningitis caused by the East Asian/Beijing genotype was independently associated with a shorter duration of illness before presentation and fewer cerebrospinal fluid (CSF) leukocytes. Older age, fewer CSF leukocytes, and the presence of hemiplegia (but not strain lineage) were independently associated with death or severe disability, although the East Asian/Beijing genotype was strongly associated with drug-resistant tuberculosis. The genotype of M. tuberculosis influenced the presenting features of pulmonary and meningeal tuberculosis. The association between the East Asian/Beijing lineage and disease progression and CSF leukocyte count suggests the lineage may alter the presentation of meningitis by influencing the intracerebral inflammatory response. In addition, increased drug resistance among bacteria of the East Asian/Beijing lineage might influence the response to treatment. This study suggests the genetic diversity of M. tuberculosis has important clinical consequences.

OBJECTIVES: To determine 1) the relationship between specific streptomycin (SM) resistance mutations and the minimum inhibitory concentration (MIC), and 2) whether these mutations are preferentially associated with the Beijing genotype in Viet Nam. METHODS: A total of 131 consecutive Mycobacterium tuberculosis isolates resistant to either isoniazid (INH) or rifampicin (RMP), collected previously, were tested for SM resistance, spoligotyped and sequenced in the rpsL, rrs and gidB genes. The MIC for 50 mutants was also determined. RESULTS: Overall, 116/131 isolates were SM-resistant. The three most frequently occurring mutation sites in rpsL and rrs were at codon 43 of rpsL (72/116, 62.1%), rpsL88 (22/116, 18.9%) and rrs514 (8/116, 6.9%). Mutations in the rrs910 region were found in two isolates (1.7%), and three isolates had mutations in both rpsL and rrs (2.6%). gidB mutations were found in both resistant and susceptible strains. Among SM-resistant isolates resistant to INH/RMP, the Beijing genotype was strongly associated with rpsL43 mutation (aOR 23.6, 95%CI 2.9-193.4, P = 0.002). The median MIC for each mutation was as follows: rpsL43 = 256 μg/ml, rpsL88 = 16 μg/ml, 515 loop = 4 μg/ml, 910 region = 8 μg/ml, and double mutation = 256 μg/ml. We found a strong association between rpsL43 and high drug resistance levels, with all rpsL43 mutants having an MIC >256 μg/ml (P < 0.001).

Background The GeneXpertMTB/RIF (Xpert) assay is now recommended by WHO for diagnosis of tuberculosis (TB) in children but evaluation data is limited. Methods One hundred and fifty consecutive HIV negative children (

Human infections with Gnathostoma spinigerum frequently occur in southern Vietnam. Previous investigations have implicated infected swamp eels (Monopterus albus) as an important source of infection to humans. Because aquaculture of M. alba is an important farming activity in Vietnam, a 2-yr study was carried out to assess the relative importance of farmed and wild eels as potential sources of gnathostome infections in humans. Eels sold for public consumption in markets in southern provinces were examined between November 2005 and August 2007. Although no infections were detected in 1,020 cultured eels and 1,021 wild-caught eels collected from November 2005 to September 2006, larval G. spinigerum (AL3) infections were first detected in September 2006 in 28 of 230 wild-caught eels (12.2%) obtained from markets in Long An province and the Hoc Mon district of Ho Chi Minh City. Subsequently, monthly surveillance of wild-caught eels from these markets was carried out through August 2007. Prevalence of AL3 varied monthly, ranging from 0.8 to 19.6%. Both prevalence and infection intensity were higher during the latter part of the rainy season (August- October). These results demonstrate that potentially zoonotic G. spinigerum larvae are common in wild eels in southern Vietnam and present a risk to consumers of raw fish dishes, especially during the annual rainy season. This information could help target public health education efforts in the region. The basis for the seasonal variation on eel infections is not known, but may be related to climate effects (flooding, higher temperatures) on intermediate host species ecology.

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Microbiological confirmation is rare, and treatment is often delayed, increasing mortality and morbidity. The GeneXpert MTB/RIF test was evaluated in a large cohort of patients with suspected tuberculous meningitis. Three hundred seventy-nine patients presenting with suspected tuberculous meningitis to the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam, between 17 April 2011 and 31 December 2012 were included in the study. Cerebrospinal fluid samples were tested by Ziehl-Neelsen smear, mycobacterial growth indicator tube (MGIT) culture, and Xpert MTB/RIF. Rifampin (RIF) resistance results by Xpert were confirmed by an MTBDR-Plus line probe assay and all positive cultures were tested by phenotypic MGIT drug susceptibility testing. Overall, 182/379 included patients (48.0%) were diagnosed with tuberculous meningitis. Sensitivities of Xpert, smear, and MGIT culture among patients diagnosed with TBM were 59.3% (108/182 [95% confidence interval {CI}, 51.8 to 66.5%]), 78.6% (143/182 [95% CI, 71.9 to 84.3%]) and 66.5% (121/182 [95% CI, 59.1 to 73.3%]), respectively. There was one false-positive Xpert MTB/RIF test (99.5% specificity). Four cases of RIF resistance (4/109; 3.7%) were identified by Xpert, of which 3 were confirmed to be multidrug-resistant (MDR) TBM and one was culture negative. Xpert MTB/RIF is a rapid and specific test for the diagnosis of tuberculous meningitis. The addition of a vortexing step to sample processing increased sensitivity for confirmed TBM by 20% ( P = 0.04). Meticulous examination of a smear from a large volume of cerebrospinal fluid (CSF) remains the most sensitive technique but is not practical in most laboratories. The Xpert MTB/RIF represents a significant advance in the early diagnosis of this devastating condition.

Background Tuberculosis (TB) in children is rarely confirmed due to the lack of effective diagnostic tools; only 10 to 15% of pediatric TB is smear positive due to paucibacillary samples and the difficulty of obtaining high-quality specimens from children. We evaluate here the accuracy of Xpert MTB/RIF in comparison with the Micoroscopic observation drug susceptibility (MODS) assay for diagnosis of TB in children using samples stored during a previously reported evaluation of the MODS assay. Methods Ninety-six eligible children presenting with suspected TB were recruited consecutively at Pham Ngoc Thach Hospital in Ho Chi Minh City Viet Nam between May to December 2008 and tested by Ziehl-Neelsen smear, MODS and Mycobacterial growth Indicator (MGIT, Becton Dickinson) culture. All samples sent by the treating clinician for testing were included in the analysis. An aliquot of processed sample deposit was stored at −20°C and tested in the present study by Xpert MTB/RIF test. 183 samples from 73 children were available for analysis by Xpert. Accuracy measures of MODS and Xpert were summarized. Results The sensitivity (%) in detecting children with a clinical diagnosis of TB for smear, MODS and Xpert were 37.9 [95% CI 25.5; 51.6], 51.7 [38.2; 65.0] and 50.0 [36.6; 63.4], respectively (per patient analysis). Xpert was significantly more sensitive than smear (P=0.046). Testing of additional samples did not increase case detection for MODS while testing of a second sputum sample by Xpert detected only two additional cases. The positive and negative predictive values (%) of Xpert were 100.0 [88.0; 100.0] and 34.1 [20.5; 49.9], respectively, while those of MODS were 96.8 [83.3; 99.9] and 33.3 [19.6; 49.5]. Conclusion MODS culture and Xpert MTB/RIF test have similar sensitivities for the detection of pediatric TB. Xpert MTB RIF is able to detect tuberculosis and rifampicin resistance within two hours. MODS allows isolation of cultures for further drug susceptibility testing but requires approximately one week to become positive. Testing of multiple samples by xpert detected only two additional cases and the benefits must be considered against costs in each setting. Further research is required to evaluate the optimal integration of Xpert into pediatric testing algorithms.

The factors that govern the development of tuberculosis disease are incompletely understood. We hypothesized that some strains of Mycobacterium tuberculosis (M. tuberculosis) are more capable of causing disseminated disease than others and may be associated with polymorphisms in host genes responsible for the innate immune response to infection. We compared the host and bacterial genotype in 187 Vietnamese adults with tuberculous meningitis (TBM) and 237 Vietnamese adults with uncomplicated pulmonary tuberculosis. The host genotype of tuberculosis cases was also compared with the genotype of 392 cord blood controls from the same population. Isolates of M. tuberculosis were genotyped by large sequence polymorphisms. The hosts were defined by polymorphisms in genes encoding Toll-interleukin 1 receptor domain containing adaptor protein (TIRAP) and Toll-like receptor-2 (TLR-2). We found a significant protective association between the Euro-American lineage of M. tuberculosis and pulmonary rather than meningeal tuberculosis (Odds ratio (OR) for causing TBM 0.395, 95% confidence intervals (C.I.) 0.193–0.806, P = 0.009), suggesting these strains are less capable of extra-pulmonary dissemination than others in the study population. We also found that individuals with the C allele of TLR-2 T597C allele were more likely to have tuberculosis caused by the East-Asian/Beijing genotype (OR = 1.57 [95% C.I. 1.15–2.15]) than other individuals. The study provides evidence that M. tuberculosis genotype influences clinical disease phenotype and demonstrates, for the first time, a significant interaction between host and bacterial genotypes and the development of tuberculosis., Author Summary Tuberculosis, caused by the bacterium Mycobacterium tuberculosis, kills over 2 million people each year. It is estimated that approximately one-third of the world population is infected with M. tuberculosis, though the majority will never develop active disease. The most severe form of tuberculosis occurs when the bacterium spreads to the brain to cause meningitis. We examined whether the genetic variation of the person and the bacteria influenced the type of disease a person develops. We have previously shown that certain mutations in genes of the human immune system can predispose adults in Vietnam to developing tuberculous meningitis. In this study we show that some strains of M. tuberculosis commonly found in Europe and America are less likely to cause tuberculous meningitis in Vietnamese adults than strains predominantly found in Asia. We then looked at the interaction between M. tuberculosis strains and mutations in human immune genes and show that a particular mutation, TLR2 T597C, is more commonly found in patients infected with the East-Asian/Beijing strains of M. tuberculosis. This is the first study to look at both the host and pathogen genotypes together in tuberculosis infection, and the findings suggest that the outcome of exposure to M. tuberculosis can depend on both the human genotype and the bacterial genotype.