102 research outputs found
Spatiotemporal evolution of SARS-CoV-2 Alpha and Delta variants during large nationwide outbreak of COVID-19, Vietnam, 2021
We analyzed 1,303 SARS-CoV-2 whole-genome sequences from Vietnam, and found the Alpha and Delta variants were responsible for a large nationwide outbreak of COVID-19 in 2021. The Delta variant was confined to the AY.57 lineage and caused >1.7 million infections and >32,000 deaths. Viral transmission was strongly affected by nonpharmaceutical interventions
The Sudden Dominance of blaCTX–M Harbouring Plasmids in Shigella spp. Circulating in Southern Vietnam
Shigellosis is a disease caused by bacteria belonging to Shigella spp. and is a leading cause of bacterial gastrointestinal infections in infants in unindustrialized countries. The Shigellae are dynamic and capable of rapid change when placed under selective pressure in a human population. Extended spectrum beta lactamases (ESBLs) are enzymes capable of degrading cephalosporins (a group of antimicrobial agents) and the genes that encode them are common in pathogenic E. coli and other related organisms in industrialized countries. In southern Vietnam, we have isolated multiple cephalosporin-resistant Shigella that express ESBLs. Furthermore, over two years these strains have replaced strains isolated from patients with shigellosis that cannot express ESBLs. Our work describes the genes responsible for this characteristic and we investigate one of the elements carrying one of these genes. These finding have implications for treatment of shigellosis and support the growing necessity for vaccine development. Our findings also may be pertinent for other countries undergoing a similar economic transition to Vietnam's and the corresponding effect on bacterial populations
A Multi-Center Randomized Trial to Assess the Efficacy of Gatifloxacin versus Ciprofloxacin for the Treatment of Shigellosis in Vietnamese Children
The bacterial genus Shigella is the most common cause of dysentery (diarrhea containing blood and/or mucus) and the disease is common in developing countries with limitations in sanitation. Children are most at risk of infection and frequently require hospitalization and antimicrobial therapy. The WHO currently recommends the fluoroquinolone, ciprofloxacin, for the treatment of childhood Shigella infections. In recent years there has been a sharp increase in the number of organisms that exhibit resistance to nalidixic acid (an antimicrobial related to ciprofloxacin), corresponding with reduced susceptibility to ciprofloxacin. We hypothesized that infections with Shigella strains that demonstrate resistance to nalidixic acid may prevent effective treatment with ciprofloxacin. We performed a randomized controlled trial to compare 3 day ciprofloxacin therapy with 3 days of gatifloxacin, a newer generation fluoroquinolone with greater activity than ciprofloxacin. We measured treatment failure and time to the cessation of individual disease symptoms in 249 children with dysentery treated with gatifloxacin and 245 treated with ciprofloxacin. We could identify no significant differences in treatment failure between the two groups or in time to the cessation of individual symptoms. We conclude that, in Vietnam, ciprofloxacin and gatifloxacin are similarly effective for the treatment of acute dysentery
Prevalence and Risk Factors for Tuberculosis Infection among Hospital Workers in Hanoi, Viet Nam
BACKGROUND: Transmission of tuberculosis (TB) to health care workers (HCWs) is a global issue. Although effective infection control measures are expected to reduce nosocomial TB, HCWs' infection has not been assessed enough in TB high burden countries. We conducted a cross-sectional study to determine the prevalence of TB infection and its risk factors among HCWs in Hanoi, Viet Nam. METHODOLOGY/PRINCIPAL FINDINGS: A total of 300 HCWs including all staff members in a municipal TB referral hospital received an interferon-gamma release assay (IGRA), QuantiFERON-TB Gold In-Tube(TM), followed by one- and two-step tuberculin skin test (TST) and a questionnaire-based interview. Agreement between the tests was evaluated by kappa statistics. Risk factors for TB infection were analyzed using a logistic regression model. Among the participants aged from 20 to 58 years (median = 40), prevalence of TB infection estimated by IGRA, one- and two-step TST was 47.3%, 61.1% and 66.3% respectively. Although the levels of overall agreement between IGRA and TST were moderate, the degree of agreement was low in the group with BCG history (kappa = 0.29). Working in TB hospital was associated with twofold increase in odds of TB infection estimated by IGRA. Increased age, low educational level and the high body mass index also demonstrated high odds ratios of IGRA positivity. CONCLUSIONS/SIGNIFICANCE: Prevalence of TB infection estimated by either IGRA or TST is high among HCWs in the hospital environment for TB care in Viet Nam and an infection control program should be reinforced. In communities with heterogeneous history of BCG vaccination, IGRA seems to estimate TB infection more accurately than any other criteria using TST
Measurement of the lifetime
An absolute measurement of the lifetime is reported using
decays in events reconstructed from data
collected by the Belle II experiment at the SuperKEKB asymmetric-energy
electron-positron collider. The total integrated luminosity of the data sample,
which was collected at center-of-mass energies at or near the
resonance, is 207.2~\mbox{fb}^{-1}. The result, fs, is the most precise
measurement to date and is consistent with previous determinations.Comment: Accepted for publication in PR
Measurements of the branching fractions for decays at Belle II
This paper reports a study of decays using
fb of data collected during 2019--2020 by the Belle II experiment at the
SuperKEKB asymmetric-energy collider, corresponding to events. We find , ,
, and signal events in the decay modes , ,
, and , respectively. The uncertainties quoted for the
signal yield are statistical only. We report the branching fractions of these
decays: where the first
uncertainty is statistical, and the second is systematic. The results are
consistent with world-average values
Precise Measurement of the D and D Lifetimes at Belle II
We report a measurement of the D and D lifetimes using D→Kπ and D→Kππ decays reconstructed in ee→ data recorded by the Belle II experiment at the SuperKEKB asymmetric-energy ee collider. The data, collected at center-of-mass energies at or near the Υ(4S) resonance, correspond to an integrated luminosity of 72 fb. The results, τ(D)=410.5±1.1(stat)±0.8(syst) fs and τ(D)=1030.4±4.7(stat)±3.1(syst) fs, are the most precise to date and are consistent with previous determinations
Measurement of the branching fraction and asymmetry of decays using pairs in Belle II data
We report measurements of the branching fraction and asymmetry in
decays reconstructed at Belle II in an
electron-positron collision sample containing
pairs. We measure a branching fraction \mathcal{B}(\Bpipi) =
(1.38 \pm 0.27 \pm 0.22) \times 10^{-6} and a asymmetry \Acp(\Bpipi)
= 0.14 \pm 0.46 \pm 0.07, where the first uncertainty is statistical and the
second is systematic
Search for a resonance in events with the Belle II experiment
We report the first search for a non-standard-model resonance decaying into
pairs in events in
the 3.6-10 GeV/ mass range. We use a 62.8 fb sample of
collisions collected at a center-of-mass energy of 10.58 GeV by the Belle II
experiment at the SuperKEKB collider. The analysis probes three different
models predicting a spin-1 particle coupling only to the heavier lepton
families, a Higgs-like spin-0 particle that couples preferentially to charged
leptons (leptophilic scalar), and an axion-like particle, respectively. We
observe no evidence for a signal and set exclusion limits at 90% confidence
level on the product of cross section and branching fraction into pairs,
ranging from 0.7 fb to 24 fb, and on the couplings of these processes. We
obtain world-leading constraints on the couplings for the leptophilic scalar
model for masses above 6.5 GeV/ and for the axion-like particle model over
the entire mass range
Determination of from untagged decays using 2019-2021 Belle II data
We present an analysis of the charmless semileptonic decay , where , from 198.0 million pairs of
mesons recorded by the Belle II detector at the SuperKEKB
electron-positron collider. The decay is reconstructed without identifying the
partner meson. The partial branching fractions are measured independently
for and as functions of
(momentum transfer squared), using 3896 and
5466 decays. The total branching fraction is
found to be for decays, where the uncertainties are statistical and
systematic, respectively. By fitting the measured partial branching fractions
as functions of , together with constraints on the nonperturbative
hadronic contribution from lattice QCD calculations, the magnitude of the
Cabibbo-Kobayashi-Maskawa matrix element , , is extracted. Here, the first uncertainty is
statistical, the second is systematic and the third is theoretical
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