Excessive antimicrobial usage and deficiencies in hygiene in meat production systems may result in undesirable human health hazards, such as the presence of antimicrobial drug residues and ...non-typhoidal Salmonella (NTS), including antimicrobial resistant (AMR) NTS. Recently, Vietnam has witnessed the emergence of integrated intensive animal production systems, coexisting with more traditional, locally-sourced wet markets. To date no systematic studies have been carried out to compare health hazards in beef, pork and chicken in different production systems. We aimed to: (1) estimate the prevalence of antimicrobial residues in beef, pork and chicken meat; (2) investigate the prevalence and levels of NTS contamination; and (3) investigate serovar distribution and AMR against critically important antimicrobials by animal species and type of retail (wet market vs. supermarket) in Vietnam. Fresh pork, beef and chicken meat samples (N=357) sourced from wet markets and supermarkets in Ho Chi Minh City (HCMC), Hanoi and Dong Thap were screened for antimicrobial residues by PremiTest, and were further investigated by Charm II. Samples from HCMC (N=113) were cultured using ISO 6579:2002/Amd 1:2007. NTS bacteria were quantified using a minimum probable number (MPN) technique. NTS isolates were assigned to serovar by Multilocus Sequence Typing (MLST), and were investigated for their phenotypic susceptibility against 32 antimicrobials. A total of 26 (7.3%) samples tested positive by PremiTest (9.5% beef, 4.1% pork and 8.4% chicken meat). Sulfonamides, tetracyclines and macrolides were detected by Charm in 3.1%, 2.8% and 2.0% samples, respectively. Overall, meat samples from wet markets had a higher prevalence of residues than those from supermarkets (9.6% vs. 2.6%) (p=0.016). NTS were isolated from 68.4% samples from HCMC. Chicken samples from wet markets had by far the highest NTS counts (median 3.2 logMPN/g). NTS isolates displayed high levels of resistance against quinolones (52.2%) and β-lactams (49.6%), but low levels against 3rd generation cephalosporins (4.4%) and aminoglycosides (0.8%). The highest adjusted prevalence of multidrug resistance (MDR) corresponded to isolates from chicken meat and pork (OR 8.3 and 1.8, respectively) (baseline=beef). S. Kentucky was the most common serovar identified (11 from chicken, 1 from beef) and 91.7% isolates was MDR. 11/12 isolates corresponded to ST198, a worldwide-disseminated multi-resistant NTS clone. We recommend stepping up policy measures to promote responsible antimicrobial use in animal production, as well as awareness about withdrawal periods to limit the hazard of residues in animal products, and improving slaughtering/hygiene procedures to limit cross-contamination with NTS, particularly in poultry wet markets.
•Antimicrobial residues were found in 7.3% meat samples (9.6% in meat from wet markets and 2.6% in meat from supermarkets).•Over two thirds (68.4%) of meat samples were contaminated with non-typhoidal Salmonella; 52.2% of isolates were multidrug resistant.•Chicken meat from wet markets had the highest loads of contamination with non-typhoidal Salmonella (median 3.2logMPN/g in positive samples).•Multidrug resistance was highest in Salmonella from chicken meat, and lowest in beef; the type of retail was not linked to increased resistance.•The most commonly identified serovar was multidrug resistant Salmonella Kentucky ST198, with high levels resistance against β-lactams and quinolones.
Crinum latifolium (CL) leaf is a source of various biologically active compounds such as alkaloid and phenolic compounds, which exhibit anti-inflammatory, antitumor, and antimicrobial effects. In the ...purpose of expanding applications for the field of bionanotechnology, we report biosynthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) by using aqueous extract from C. latifolium leaf and explore antibacterial activity and catalytic performance for degradation of pollutants. The formation of CL-AgNPs and CL-AuNPs is confirmed and optimized by UV-visible spectroscopy with surface plasmon resonance (SPR) peaks at around 402 and 539 nm, respectively. The spherical CL-AgNPs have an average diameter of 20.5 nm and the multishaped CL-AuNPs possess an average size of 17.6 nm. The actions of four bacterial strains were strongly inhibited by using the CL-AgNPs. Furthermore, the biosynthesized metallic nanoparticles (MNPs) exhibited the excellent catalytic degradation performance of pollutants.
Data on breakthrough SARS-CoV-2 Delta variant infections in vaccinated individuals are limited.
We studied breakthrough infections among Oxford-AstraZeneca vaccinated healthcare workers in an ...infectious diseases hospital in Vietnam. We collected demographic and clinical data alongside serial PCR testing, measurement of SARS-CoV-2 antibodies, and viral whole-genome sequencing.
Between 11th–25th June 2021 (7-8 weeks after the second dose), 69 staff tested positive for SARS-CoV-2. 62 participated in the study. Most were asymptomatic or mildly symptomatic and all recovered. Twenty-two complete-genome sequences were obtained; all were Delta variant and were phylogenetically distinct from contemporary viruses obtained from the community or from hospital patients admitted prior to the outbreak. Viral loads inferred from Ct values were 251 times higher than in cases infected with the original strain in March/April 2020. Median time from diagnosis to negative PCR was 21 days (range 8–33). Neutralizing antibodies (expressed as percentage of inhibition) measured after the second vaccine dose, or at diagnosis, were lower in cases than in uninfected, fully vaccinated controls (median (IQR): 69.4 (50.7-89.1) vs. 91.3 (79.6-94.9), p=0.005 and 59.4 (32.5-73.1) vs. 91.1 (77.3-94.2), p=0.043). There was no correlation between vaccine-induced neutralizing antibody levels and peak viral loads or the development of symptoms.
Breakthrough Delta variant infections following Oxford-AstraZeneca vaccination may cause asymptomatic or mild disease, but are associated with high viral loads, prolonged PCR positivity and low levels of vaccine-induced neutralizing antibodies. Epidemiological and sequence data suggested ongoing transmission had occurred between fully vaccinated individuals.
Wellcome and NIH/NIAID
Chemical composition and bioactivities including bacterial and fungal resistance of the essential oils extracted from leaves of
Piper betle
L. (
T
) and
Cleistocalyx operculatus
L. (
V
) and aerial ...parts of
Ageratum conyzoides
L. (
H
) were investigated. The components presenting in the essential oils of the natural sources were analysized by a gas chromatography–mass spectrometry. Molecular docking simulation was utilised to support an antimicrobial mechanism of the essential oil compounds on
Candida albicans
fungus and
Streptococcus pyogenes
bacteria. This was based on the inhibition of the extracted compounds onto the microbial proteins, i.e. 4ESW and P0C0C7, respectively. There are 32 compounds identified in total in the three essential oils. The most effective inhibitors are the following: (i) chavicol acetate (
T3
), eugenol acetate (
T11
) and eugenol (
T4
) found in
Piper betle
L.; (ii) precocene II (
H10
) and precocene I (
H6
) found in
Ageratum conyzoides
L.; and (iii) caryophyllene oxide (
V15
) and
cis
-Lanceol (
V19
) found in
Cleistocalyx operculatus
L.. The overall antifungal and antibacterial capability of the investigated essential oils given indirect justification via their average inhabitability towards the two proteins accords with the order
Piper betle
L.
Ageratum conyzoides
L.
Cleistocalyx operculatus
L.. The results suggest these as promising natural sources for antimicrobial remedies.
Starting from April 1st, 2020, the nationwide partial lockdown in Vietnam has shown the effectiveness in stopping the community transmission of COVID-19, however, it also produced adverse impacts on ...the economy and inhabitants’ life. A cross-sectional study using a web-based approach was conducted in the second week of April 2020 to examine the influence of the national social distancing on the quality of life and economic well-being of Vietnamese citizens under COVID-19 pandemic. The data included socio-economic characteristics, impact of COVID-19 on household income, health status, and health-related quality of life (HRQOL). Ordered logistic regression and multivariable Tobit regression model were employed to examine factors correlated to income change and HRQOL. Results showed that among 341 participants, 66.9% reported household income loss due to the impact of COVID-19. People holding undergraduate degrees, working in other sectors rather than healthcare, and having definite-term contract had a higher likelihood of income reduction. The mean score of EQ-5D-5L and EQ-VAS was 0.95 (± 0.07) and 88.2 (± 11.0), respectively. The domain of Anxiety/Depression had the highest proportion of reporting any problems among 5 dimensions of EQ-5D-5L (38.7%). Being female, having chronic conditions and living in the family with 3–5 members were associated with lower HRQOL scores. A comprehensive assessment of the influence of COVID-19 along with public health interventions, especially mental health programs, should be implemented to mitigate the negative effects of this pandemic on the economic status and quality of life of citizens.
We studied the development and persistence of neutralizing antibodies against SARS-CoV-2 ancestral strain, and Delta and Omicron (BA.1 and BA.2) variants in Vietnamese healthcare workers (HCWs) up to ...15 weeks after booster vaccination. We included 47 HCWs, including group 1 (G1, N = 21) and group 2 (G2; N = 26) without and with breakthrough Delta variant infection before booster immunization, respectively). The study participants had completed primary immunization with ChAdOx1-S and booster vaccination with BNT162b2. Neutralizing antibodies were measured using a surrogate virus neutralization assay. Of the 21 study participants in G1, neutralizing antibodies against ancestral strain, Delta variant, BA.1, and BA.2 were (almost) abolished at month 8 after the second dose, but all had detectable neutralizing antibodies to the study viruses at week 2 post booster dose. Of the 26 study participants in G2, neutralizing antibody levels to BA.1 and BA.2 were significantly higher than those to the corresponding viruses measured at week 2 post breakthrough infection and before the booster dose. At week 15 post booster vaccination, neutralizing antibodies to BA.1 and BA.2 dropped significantly, with more profound changes observed in those without breakthrough Delta variant infection. Booster vaccination enhanced neutralizing activities against ancestral strain and Delta variant compared with those induced by primary vaccination. These responses were maintained at high levels for at least 15 weeks. Our findings emphasize the importance of the first booster dose in producing cross-neutralizing antibodies against Omicron variant. A second booster to maintain long-term vaccine effectiveness against the currently circulating variants merits further research.
Among mitotic kinases, Aurora kinases are the most widely studied, since their expression is restricted to mitosis. They play a key role in chromosome segregation and cell polyploidy. Aurora kinases ...are important therapeutic targets, and several research groups have directed their efforts toward the identification of kinase inhibitors. The aim of this study is to screen and characterize Aurora kinase inhibitors from natural substances extracted from plants that are used in the Vietnamese pharmacopoeia. We have characterized in vitro Derrone, extracted from Erythrina orientalis L. MURR, as a novel Aurora kinase inhibitor. This compound exhibited an ability to inhibit the phosphorylation of histone H3 at ser10 both in kinase assay and at the cellular level. The compound was more effective against Aurora kinase B, with a lower IC50 value as compared to Aurora A. Moreover, it impaired the mitotic spindle checkpoint and led to endoreduplication in cancer cells, a phenomenon caused by an Aurora B inhibitor. Interestingly, using the xCelligence system and real-time cell analysis (RTCA) software, we set up a comparison of cell proliferation profiles between cancer cells treated with Derrone and VX680—a well-known Aurora kinase inhibitor—and we found that these profiles exhibited considerable similarity in cell morphology, growth, and death. Additionally, Derrone significantly inhibited the formation and growth of MCF7 tumor spheroids.
Eighteen active substances, including 17 organosulfur compounds found in garlic essential oil (T), were identified by GC–MS analysis. For the first time, using the molecular docking technique, we ...report the inhibitory effect of the considered compounds on the host receptor angiotensin-converting enzyme 2 (ACE2) protein in the human body that leads to a crucial foundation about coronavirus resistance of individual compounds on the main protease (PDB6LU7) protein of SARS-CoV-2. The results show that the 17 organosulfur compounds, accounting for 99.4% contents of the garlic essential oil, have strong interactions with the amino acids of the ACE2 protein and the main protease PDB6LU7 of SARS-CoV-2. The strongest anticoronavirus activity is expressed in allyl disulfide and allyl trisulfide, which account for the highest content in the garlic essential oil (51.3%). Interestingly, docking results indicate the synergistic interactions of the 17 substances, which exhibit good inhibition of the ACE2 and PDB6LU7 proteins. The results suggest that the garlic essential oil is a valuable natural antivirus source, which contributes to preventing the invasion of coronavirus into the human body.
To describe the prevalence of antimicrobial resistance among commensal Escherichia coli isolates on household and small-scale chicken farms, common in southern Vietnam, and to investigate the ...association of antimicrobial resistance with farming practices and antimicrobial usage.
We collected data on farming and antimicrobial usage from 208 chicken farms. E. coli was isolated from boot swab samples using MacConkey agar (MA) and MA with ceftazidime, nalidixic acid or gentamicin. Isolates were tested for their susceptibility to 11 antimicrobials and for ESBL production. Risk factor analyses were carried out, using logistic regression, at both the bacterial population and farm levels.
E. coli resistant to gentamicin, ciprofloxacin and third-generation cephalosporins was detected on 201 (96.6%), 191 (91.8%) and 77 (37.0%) of the farms, respectively. Of the 895 E. coli isolates, resistance to gentamicin, ciprofloxacin and third-generation cephalosporins was detected in 178 (19.9%), 291 (32.5%) and 29 (3.2%) of the isolates, respectively. Ciprofloxacin resistance was significantly associated with quinolone usage (OR = 2.26) and tetracycline usage (OR = 1.70). ESBL-producing E. coli were associated with farms containing fish ponds (OR = 4.82).
Household and small farms showed frequent antimicrobial usage associated with a high prevalence of resistance to the most commonly used antimicrobials. Given the weak biocontainment, the high prevalence of resistant E. coli could represent a risk to the environment and to humans.
Abstract
Background
Little is known about the natural history of asymptomatic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.
Methods
We conducted a prospective study at a ...quarantine center for coronavirus disease 2019 in Ho Chi Minh City, Vietnam. We enrolled quarantined people with reverse-transcription polymerase chain reaction (RT-PCR)–confirmed SARS-CoV-2 infection, collecting clinical data, travel and contact history, and saliva at enrollment and daily nasopharyngeal/throat swabs (NTSs) for RT-PCR testing. We compared the natural history and transmission potential of asymptomatic and symptomatic individuals.
Results
Between 10 March and 4 April 2020, 14 000 quarantined people were tested for SARS-CoV-2; 49 were positive. Of these, 30 participated in the study: 13 (43%) never had symptoms and 17 (57%) were symptomatic. Seventeen (57%) participants imported cases. Compared with symptomatic individuals, asymptomatic people were less likely to have detectable SARS-CoV-2 in NTS collected at enrollment (8/13 62% vs 17/17 100%; P = .02). SARS-CoV-2 RNA was detected in 20 of 27 (74%) available saliva samples (7 of 11 64% in the asymptomatic group and 13 of 16 81% in the symptomatic group; P = .56). Analysis of RT-PCR positivity probability showed that asymptomatic participants had faster viral clearance than symptomatic participants (P < .001 for difference over the first 19 days). This difference was most pronounced during the first week of follow-up. Two of the asymptomatic individuals appeared to transmit SARS-CoV-2 to 4 contacts.
Conclusions
Asymptomatic SARS-CoV-2 infection is common and can be detected by analysis of saliva or NTSs. The NTS viral loads fall faster in asymptomatic individuals, but these individuals appear able to transmit the virus to others.
Forty-three percent (13/30) of confirmed SARS-CoV-2–infected individuals were asymptomatic, with the virus detected in both saliva and nasopharyngeal/throat swabs. Viral clearance was faster in asymptomatic individuals, but they still appeared able to pass the infection to others.
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