A novel huperzine A-producing endophytic fungus Fusarium sp. Rsp5.2 isolated from Huperzia serrate.

The isolation, identification and characterization of a novel huperzine A (HupA)-producing fungal strain Rsp5.2 isolated from Huperzia serrata (Thunb. ex Murray) Trev. in Vietnam. The fifty-eight endophytic fungi were recovered from roots of natural H. serrata in Lao Cai province of northern Vietnam and screened for HupA-producing by thin-layer chromatography (TLC). The only one of the 58 strains, Rsp5.2, could produce HupA. The amount of HupA produced by Rsp5.2 was quantified to be 19.45 µg g-1 dried mycelium by high-performance liquid chromatography (HPLC). Acetylcholine esterase (AchE) inhibition (IC50) of the crude HupA extract from Rsp5.2 fermentation broth was 2.849 ± 0.0026 µg mL-1. The fungus was identified as Fusarium sp. Rsp5.2 by morphological characteristics and Internal Transcribed Spacer (ITS) sequences. This is the first report of Fusarium sp. as a HupA-producing endophyte isolated from H. serrata.

Sodium Polyanethol Sulfonate Modulates Natural Transformation of SigH-Expressing Staphylococcus aureus.

Expression of genes required for natural genetic competence in Staphylococcus aureus is controlled by an alternative transcription sigma factor, SigH. However, even in the SigH-expressing cells, the DNA transformation efficiency varies depending on culture conditions. We report here that cells grown in the competence-inducing medium (CS2 medium) exhibit enlarged morphology with disintegrated cell walls. Notably, an autolysis inhibitor, Sodium Polyanethol Sulfonate (SPS), facilitated transformation in CS2 medium in a dose-dependent manner, suggesting the involvement of the cell wall metabolism in transformation. However, the transformation efficiency of cells grown in TSB was not improved by physical or enzymatic damage on the cell walls.

Nanodiamond enhances immune responses in mice against recombinant HA/H7N9 protein.

BACKGROUND: The continuing spread of the newly emerged H7N9 virus among poultry in China, as well as the possibility of human-to-human transmission, has attracted numerous efforts to develop an effective vaccine against H7N9. The use of nanoparticles in vaccinology is inspired by the fact that most pathogens have a dimension within the nano-size range and therefore can be processed efficiently by the immune system, which leads to a potent immune response. Herein, we report a facile approach to increase antigen size to achieve not only fast but also effective responses against the recombinant HA/H7N9 protein via a simple conjugation of the protein onto the surface of nanodiamond particles. RESULTS: In this study, trimeric Haemagglutinin (H7) that is transiently expressed in N. benthamiana was purified using affinity chromatography, and its trimeric state was revealed successfully by the cross-linking reaction. The trimeric H7 solution was subsequently mixed with a nanodiamond suspension in different ratios. The successful conjugation of the trimeric H7 onto the surface of nanodiamond particles was demonstrated by the changes in size and Zeta-potential of the particles before and after protein coating, Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and Western-blot analysis. Next, biofunction of the protein-nanodiamond conjugates was screened using a haemagglutination assay. A mixture containing 5 µg of trimeric H7 and 60 µg of nanodiamond corresponds to a ratio of 1:12 (w/w) of agglutinated chicken red blood cells at HA titer of 1024, which is 512-fold higher than the HA titer of free trimeric H7. After the 2nd and 3rd immunization in mice, ELISA and Western blot analyses demonstrated that the physical mixture of trimeric H7 protein and nanodiamond (1:12, w/w) elicited statistically significant stronger H7-specific-IgG response demonstrated by higher amounts of H7N9-specific IgG (over 15.4-fold with P < 0.05 after the second immunization). CONCLUSIONS: These results indicated a potential effect inherent to nanodiamond towards modulating immune systems, which should be further evaluated and broadly applied in nanovaccine development.

Horizontal gene transmission of the cfr gene to MRSA and Enterococcus: role of Staphylococcus epidermidis as a reservoir and alternative pathway for the spread of linezolid resistance.

OBJECTIVES: Linezolid resistance mediated by the cfr gene represents a global concern due to its dissemination among multiresistant nosocomial pathogens such as MRSA and Enterococcus. In the present work, we have evaluated the in vitro transmission of cfr pSCFS7-like plasmids from two Staphylococcus epidermidis ST2 strains (SE45 and SE50) isolated in Spanish hospitals, to clinical MRSA and Enterococcus spp. isolates obtained in Japan, a country in which cfr has not been detected yet. We have also investigated alternative mechanisms of horizontal gene transfer involved in the spread of the cfr gene. METHODS: MRSA (n = 16) and Enterococcus spp. (n = 8) clinical isolates were used as recipients in conjugative experiments. Bacteriophage-mediated transmission was tested using MR83a phage and N315, COL and Mu50 strains. A transformation assay was carried out using a natural competent strain derived from N315. RESULTS: The SE45 strain was able to transfer the cfr gene to all strains tested, while transmission from SE50 was observed only to a few strains and with less efficiency. No transmission was observed to Enterococcus spp. isolates. Even though conjugation is thought to be the main mechanism of cfr dissemination, we have demonstrated that transduction can be considered an alternative pathway for transmission of the cfr gene between MRSA strains. However, the results suggest an absence of transmission by natural transformation. CONCLUSIONS: Linezolid resistance mediated by cfr vectors, such as pSCFS7-like plasmids, can be efficiently transferred to clinical MRSA in Japanese isolates. After reaching the staphylococcal pool, the cfr gene could be spread among MRSA strains by either conjugation or transduction.

Mapping cerebral perfusion in mice under various anesthesia levels using highly sensitive BOLD MRI with transient hypoxia.

Cerebral perfusion is critical for the early detection of neurological diseases and for effectively monitoring disease progression and treatment responses. Mouse models are widely used in brain research, often under anesthesia, which can affect vascular physiology. However, the impact of anesthesia on regional cerebral blood volume and flow in mice has not been thoroughly investigated. In this study, we have developed a whole-brain perfusion MRI approach by using a 5-second nitrogen gas stimulus under inhalational anesthetics to induce transient BOLD dynamic susceptibility contrast (DSC). This method proved to be highly sensitive, repeatable within each imaging session, and across four weekly sessions. Relative cerebral blood volumes measured by BOLD DSC agree well with those by contrast agents. Quantitative cerebral blood volume and flow metrics were successfully measured in mice under dexmedetomidine and various isoflurane doses using both total vasculature-sensitive gradient-echo and microvasculature-sensitive spin-echo BOLD MRI. Dexmedetomidine reduces cerebral perfusion, while isoflurane increases cerebral perfusion in a dose-dependent manner.

Impact of long COVID-19 on posttraumatic stress disorder as modified by health literacy: an observational study in Vietnam.

BACKGROUND: The prevalence of posttraumatic stress disorder (PTSD) has increased, particularly among individuals who have recovered from coronavirus disease 2019 (COVID-19) infection. Health literacy is considered a "social vaccine" that helps people respond effectively to the pandemic. We aimed to investigate the association between long COVID-19 and PTSD, and to examine the modifying role of health literacy in this association. METHODS: A cross-sectional study was conducted at 18 hospitals and health centers in Vietnam from December 2021 to October 2022. We recruited 4,463 individuals who had recovered from COVID-19 infection for at least 4 weeks. Participants provided information about their sociodemographics, clinical parameters, health-related behaviors, health literacy (using the 12-item short-form health literacy scale), long COVID-19 symptoms and PTSD (Impact Event Scale-Revised score of 33 or higher). Logistic regression models were used to examine associations and interactions. RESULTS: Out of the study sample, 55.9% had long COVID-19 symptoms, and 49.6% had PTSD. Individuals with long COVID-19 symptoms had a higher likelihood of PTSD (odds ratio [OR], 1.86; 95% confidence interval [CI], 1.63-2.12; p<0.001). Higher health literacy was associated with a lower likelihood of PTSD (OR, 0.98; 95% CI, 0.97-0.99; p=0.001). Compared to those without long COVID-19 symptoms and the lowest health literacy score, those with long COVID-19 symptoms and a 1-point health literacy increment had a 3% lower likelihood of PTSD (OR, 0.97; 95% CI, 0.96-0.99; p=0.001). CONCLUSION: Health literacy was found to be a protective factor against PTSD and modified the negative impact of long COVID-19 symptoms on PTSD.

Determinants of Frailty among Patients with Type 2 Diabetes In Urban Hospital.

Objectives: Frailty and diabetes are on the rise due to the aging population. This study was conducted to examine frailty conditions among patients with Type 2 diabetes (T2DM) in Hanoi, Vietnam, as well as determine its associated factors. Methods: A cross-sectional study on T2DM patients at an urban hospital. This study assessed the frailty status using the FRAIL questionnaire. Socio-demographic, clinical, and paraclinical characteristics were obtained. Multivariate regression models were performed to detect factors associated with frailty. Results: Of 379 patients, the FRAIL scale results showed that 8/379 patients were at the frailty level (2.1%), and 33/379 patients were at the pre-frailty level (8.7%). Patients who had above high school education and were retired were at lower risk of pre-frailty/frailty than those with high school education or below, and self-employed, respectively. Conversely, patients with a higher number of comorbidities were more likely to develop pre-frailty and frailty. Conclusion: This study showed a low prevalence of pre-frailty and frailty among T2DM patients. It is necessary to manage diabetes carefully and strictly control the comorbidities in this population. Interventions should focus on higher risk populations, such as those with low education levels and self-employment.

Outpatient antibiotic prescribing for acute respiratory infections in Vietnamese primary care settings by the WHO AWaRe (Access, Watch and Reserve) classification: An analysis using routinely collected electronic prescription data.

Background: This study aims to investigate patterns of antibiotic prescribing and to determine patient-specific factors associated with the choice of antibiotics by the World Health Organization's Access-Watch-Reserve (WHO AWaRe) class for acute respiratory infections (ARIs) in rural primary care settings in northern Vietnam. Methods: We retrospectively reviewed health records for outpatients who were registered with the Vietnamese Health Insurance Scheme, visited one of 112 commune health centres in 6 rural districts of Nam Dinh province, Vietnam during 2019, and were diagnosed with ARIs. Patient-level prescription data were collected from the electronic patient databases. We used descriptive statistics to investigate patterns of antibiotic prescribing, with the primary outcomes including total antibiotic prescriptions and prescriptions by WHO AWaRe group. We identified patient-specific factors associated with watch-group antibiotic prescribing through multivariable logistic regression analysis. Findings: Among 193,010 outpatient visits for ARIs observed in this study, 187,144 (97.0%) resulted in an antibiotic prescription, of which 172,976 (92.5%) were access-antibiotics, 10,765 (5.6%) were watch-antibiotics, 3366 (1.8%) were not-recommended antibiotics. No patients were treated with reserve-antibiotics. The proportion of watch-antibiotic prescription was highest amongst children under 5-years old (18.1%, compared to 9.5% for 5-17-years, 4.9% for 18-49-years, 4.3% for 50-64-years, and 3.7% for 65-and-above-years). In multivariable logistic regression, children, district, ARI-type, comobid chronic respiratory illness, and follow-up visit were associated with higher likelihood of prescribing watch-group antibiotics. Interpretation: The alarmingly high proportion of antibiotic prescriptions for ARIs in primary care, and the frequent use of watch-antibiotics for children, heighten concerns around antibiotic overuse at the community level. Antimicrobial stewardship interventions and policy attention are needed in primary care settings to tackle the growing threat of antibiotic resistance. Funding: This work was supported through Australian government and UK aid from the UK government funding to FIND (Foundation for Innovative New Diagnostics) grant number FO17-0015, in addition to a Wellcome Trust grant (213920/Z/18/Z), and an Oxford University Clinical Research Unit internal grant from the Wellcome Trust Africa Asia Programme core grant in Vietnam (106680/Z/14/Z).

Sequential Organ Failure Assessment (SOFA) Score for predicting mortality in patients with sepsis in Vietnamese intensive care units: a multicentre, cross-sectional study.

OBJECTIVES: To compare the accuracy of the Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) Scores in predicting mortality among intensive care unit (ICU) patients with sepsis in a low-income and middle-income country. DESIGN: A multicentre, cross-sectional study. SETTING: A total of 15 adult ICUs throughout Vietnam. PARTICIPANTS: We included all patients aged ≥18 years who were admitted to ICUs for sepsis and who were still in ICUs from 00:00 to 23:59 of the specified study days (ie, 9 January, 3 April, 3 July and 9 October of the year 2019). PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was hospital all-cause mortality (hospital mortality). We also defined the secondary outcome as all-cause deaths in the ICU (ICU mortality). RESULTS: Of 252 patients, 40.1% died in hospitals, and 33.3% died in ICUs. SOFA Score (areas under the receiver operating characteristic curve (AUROC): 0.688 (95% CI 0.618 to 0.758); cut-off value≥7.5; PAUROC<0.001) and APACHE II Score (AUROC: 0.689 (95% CI 0.622 to 0.756); cut-off value ≥20.5; PAUROC<0.001) both had a poor discriminatory ability for predicting hospital mortality. However, the discriminatory ability for predicting ICU mortality of SOFA (AUROC: 0.713 (95% CI 0.643 to 0.783); cut-off value≥9.5; PAUROC<0.001) was fair and was better than that of APACHE II Score (AUROC: 0.672 (95% CI 0.603 to 0.742); cut-off value≥18.5; PAUROC<0.001). A SOFA Score≥8 (adjusted OR (AOR): 2.717; 95% CI 1.371 to 5.382) and an APACHE II Score≥21 (AOR: 2.668; 95% CI 1.338 to 5.321) were independently associated with an increased risk of hospital mortality. Additionally, a SOFA Score≥10 (AOR: 2.194; 95% CI 1.017 to 4.735) was an independent predictor of ICU mortality, in contrast to an APACHE II Score≥19, for which this role did not. CONCLUSIONS: In this study, SOFA and APACHE II Scores were worthwhile in predicting mortality among ICU patients with sepsis. However, due to better discrimination for predicting ICU mortality, the SOFA Score was preferable to the APACHE II Score in predicting mortality.Clinical trials registry - India: CTRI/2019/01/016898.

Whole-brain perfusion mapping in mice by dynamic BOLD MRI with transient hypoxia.

Non-invasive mapping of cerebral perfusion is critical for understanding neurovascular and neurodegenerative diseases. However, perfusion MRI methods cannot be easily implemented for whole-brain studies in mice because of their small size. To overcome this issue, a transient hypoxia stimulus was applied to induce a bolus of deoxyhemoglobins as an endogenous paramagnetic contrast in blood oxygenation level-dependent (BOLD) MRI. Based on stimulus-duration-dependent studies, 5 s anoxic stimulus was chosen, which induced a decrease in arterial oxygenation to 59%. Dynamic susceptibility changes were acquired with whole-brain BOLD MRI using both all-vessel-sensitive gradient-echo and microvascular-sensitive spin-echo readouts. Cerebral blood flow (CBF) and cerebral blood volume (CBV) were quantified by modeling BOLD dynamics using a partial-volume-corrected arterial input function. In the mouse under ketamine/xylazine anesthesia, total CBF and CBV were 112.0 ± 15.0 ml/100 g/min and 3.39 ± 0.59 ml/100 g (n = 15 mice), respectively, whereas microvascular CBF and CBV were 85.8 ± 6.9 ml/100 g/min and 2.23 ± 0.27 ml/100 g (n = 7 mice), respectively. Regional total vs. microvascular perfusion metrics were highly correlated but a slight mismatch was observed in the large-vessel areas and cortical depth profiles. Overall, this non-invasive, repeatable, simple hypoxia BOLD-MRI approach is viable for perfusion mapping of rodents.

Predictive validity of the quick Sequential Organ Failure Assessment (qSOFA) score for the mortality in patients with sepsis in Vietnamese intensive care units.

BACKGROUND: The simple scoring systems for predicting the outcome of sepsis in intensive care units (ICUs) are few, especially for limited-resource settings. Therefore, this study aimed to evaluate the accuracy of the quick Sequential (Sepsis-Related) Organ Failure Assessment (qSOFA) score in predicting the mortality of ICU patients with sepsis in Vietnam. METHODS: We did a multicenter cross-sectional study of patients with sepsis (≥18 years old) presenting to 15 adult ICUs throughout Vietnam on the specified days (i.e., 9th January, 3rd April, 3rd July, and 9th October) representing the different seasons of 2019. The primary and secondary outcomes were the hospital and ICU all-cause mortalities, respectively. The area under the receiver operating characteristic curve (AUROC) was calculated to determine the discriminatory ability of the qSOFA score for deaths in the hospital and ICU. The cut-off value of the qSOFA scores was determined by the receiver operating characteristic curve analysis. Upon ICU admission, factors associated with the hospital and ICU mortalities were assessed in univariable and multivariable logistic models. RESULTS: Of 252 patients, 40.1% died in the hospital, and 33.3% died in the ICU. The qSOFA score had a poor discriminatory ability for both the hospital (AUROC: 0.610 [95% CI: 0.538 to 0.681]; cut-off value: ≥2.5; sensitivity: 34.7%; specificity: 84.1%; PAUROC = 0.003) and ICU (AUROC: 0.619 [95% CI: 0.544 to 0.694]; cutoff value: ≥2.5; sensitivity: 36.9%; specificity: 83.3%; PAUROC = 0.002) mortalities. However, multivariable logistic regression analyses show that the qSOFA score of 3 was independently associated with the increased risk of deaths in both the hospital (adjusted odds ratio, AOR: 3.358; 95% confidence interval, CI: 1.756 to 6.422) and the ICU (AOR: 3.060; 95% CI: 1.651 to 5.671). CONCLUSION: In our study, despite having a poor discriminatory value, the qSOFA score seems worthwhile in predicting mortality in ICU patients with sepsis in limited-resource settings. CLINICAL TRIAL REGISTRATION: Clinical trials registry-India: CTRI/2019/01/016898.

Factors relating to mortality in septic patients in Vietnamese intensive care units from a subgroup analysis of MOSAICS II study.

Sepsis is the most common cause of in-hospital deaths, especially from low-income and lower-middle-income countries (LMICs). This study aimed to investigate the mortality rate and associated factors from sepsis in intensive care units (ICUs) in an LMIC. We did a multicenter cross-sectional study of septic patients presenting to 15 adult ICUs throughout Vietnam on the 4 days representing the different seasons of 2019. Of 252 patients, 40.1% died in hospital and 33.3% died in ICU. ICUs with accredited training programs (odds ratio, OR: 0.309; 95% confidence interval, CI 0.122-0.783) and completion of the 3-h sepsis bundle (OR: 0.294; 95% CI 0.083-1.048) were associated with decreased hospital mortality. ICUs with intensivist-to-patient ratio of 1:6 to 8 (OR: 4.533; 95% CI 1.621-12.677), mechanical ventilation (OR: 3.890; 95% CI 1.445-10.474) and renal replacement therapy (OR: 2.816; 95% CI 1.318-6.016) were associated with increased ICU mortality, in contrast to non-surgical source control (OR: 0.292; 95% CI 0.126-0.678) which was associated with decreased ICU mortality. Improvements are needed in the management of sepsis in Vietnam such as increasing resources in critical care settings, making accredited training programs more available, improving compliance with sepsis bundles of care, and treating underlying illness and shock optimally in septic patients.

Establishment of Recombinase Polymerase Amplification assay for rapid and sensitive detection of Orientia tsutsugamushi in Southeast Asia.

Scrub typhus, caused by Orientia tsutsugamushi, is a common fever in parts of Southern and Southeast Asia. As delayed diagnosis of scrub typhus leads to inappropriate treatment and high mortality rates, of up to 70%, sensitive and rapid detection of O. tsutsugamushi is required for timely and appropriate treatment. Molecular assays, such as PCR and real-time PCR, have been shown to be more sensitive than conventional immunoassay, however, they are only available in centralized laboratories. In contrast to PCR assays, Recombinase Polymerase Amplification (RPA) is conducted under a constant temperature ranging from 24°C to 45°C. Therefore, this technology is very promising for nucleic acid testing in the field, and in resource-limited areas. An RPA assay for the detection of O. tsutsugamushi based on the target gene encoding for the 47 kDa outer membrane protein has been reported, but the primer and probe sequences of this assay are suboptimal for detection of the majority of recently published sequences of O. tsutsugamushi isolates from Southeast Asia. We have established a real-time RPA assay with primer and probe sequences that are optimized for most Southeast Asia's isolates of O. tsutsugamushi. As a result, the new RPA assay showed better performance than the previous assay in detecting O. tsutsugamushi in clinical samples of scrub typhus cases found in Vietnam. The specificity of RPA assay was also evaluated using genomic DNA from microorganisms commonly encountered in the differential diagnosis of scrub typhus, and blood samples from healthy controls and O. tsutsugamushi negative confirmed cases.

The emergence of plasmid-borne cfr-mediated linezolid resistant-staphylococci in Vietnam.

OBJECTIVES: Linezolid is one of the last resort antibiotics effectively used in the treatment of infections caused by multidrug-resistant Gram-positive bacteria. Recent outbreaks of Linezolid resistance have been the great concern worldwide, while many countries have not experienced it. In this work, we aimed to evaluate the existence of linezolid resistance and further clarify potential resistance mechanism(s) in staphylococcal isolates obtained from the hospital in Vietnam, a country in which linezolid resistance had not been previously detected. METHODS: Seventy staphylococcal clinical isolates including MRSA (n=63) and methicillin-resistant coagulase-negative staphylococci (MRCNS, n=7) were collected and analyzed for linezolid resistance. Linezolid-resistant isolates were submitted for whole genome sequencing to search for the resistance determinants. RESULTS: We identified two coagulase-negative staphylococcal isolates that were resistant to linezolid. Whole genome sequencing revealed several alterations in the 23S rRNA and L3, L17, L22, L24, L30 ribosomal proteins. Importantly, both isolates harbour the chloramphenicol/florfenicol resistance (cfr) gene on a plasmid. The plasmid was closely identical to the pLRSA417 plasmid that was originally reported in China. CONCLUSIONS: To the best of our knowledge, this is the first report of cfr-mediated linezolid resistance in clinically isolated staphylococci in Vietnam. We suggest that adequate surveillance is necessary to monitor the dissemination of linezolid resistance among staphylococcal species and other important pathogens.

Pharmacokinetics and ex vivo pharmacodynamic antimalarial activity of dihydroartemisinin-piperaquine in patients with uncomplicated falciparum malaria in Vietnam.

Compared to healthy subjects, malaria patients show a reduction in the mean oral clearance (1.19 versus 5.87 liters/h/kg of body weight) and apparent volume of distribution (1.47 versus 8.02 liters/kg) of dihydroartemisinin in Vietnamese patients following treatment with dihydroartemisinin-piperaquine (Artekin) for uncomplicated Plasmodium falciparum. Dihydroartemisinin is responsible for most of the ex vivo antimalarial activity of dihydroartemisinin-piperaquine.

The complete mitochondrial genome of Mong Cai pig (Sus scrofa) in Vietnam.

The Mong Cai pig is an indigenous breed and popularly raised as maternal line in northern Vietnam. In this study, the complete mitochondrial genome sequence of the Mong Cai pig is reported. The total length of this mitochondrial genome is 16 632 bp, including 1 non-coding control region (D-loop region), two ribosomal RNA genes, 13 protein-coding genes and 22 transfer RNA genes. The phylogenetic tree of 162 pig complete mitogenomes reveals a very close relationship between Mong Cai pig in Vietnam and Bama miniature pig in southern China. This complete mitochondrial genome sequence of Mong Cai pig is useful to further genetic studies on adaptation and performance.