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1.
Pathogens ; 13(5)2024 May 10.
Article in English | MEDLINE | ID: mdl-38787252

ABSTRACT

Clostridium perfringens is one of the most important zoonotic pathogens as it can cause food poisoning in humans and necrotic enteritis in both animals and humans. Meat, especially pork and chicken meat, is considered the main vehicle for the transmission of C. perfringens from animals to humans. The purpose of this study was to determine the prevalence, toxinotype, and antimicrobial resistance profile of C. perfringens isolated from pork and chicken meat sold in Vietnam. The isolation results showed that 15/50 (30%) of pork samples and 8/50 (16%) of chicken meat samples were contaminated with C. perfringens. The isolates exhibited their highest resistance rate to tetracycline (21/23; 91.30%) and clindamycin (10/23; 43.48%). On the contrary, their lowest resistance rates were observed in response to imipenem (2/23; 8.70%) and cefoxitin (1/23; 4.35%). In particular, 34.78% (8/23) of C. perfringens isolates were identified to be multidrug-resistant strains. The results of toxin genotyping indicated that all isolates were positive for the cpa gene and belonged to type A.

2.
Front Surg ; 11: 1366338, 2024.
Article in English | MEDLINE | ID: mdl-38601876

ABSTRACT

Background: Iliac artery stenosis or occlusion is a critical condition that can severely impact a patient's quality of life. The effectiveness of balloon angioplasty and intraluminal stenting for the treatment of iliac artery lesions classified as TASC II A and B was evaluated in this single-center prospective study. Methods: Conducted between October 2016 and September 2020 at Cho Ray Hospital's Vascular Surgery Department, this prospective study involved PAD patients categorized by TASC II A and B classifications who underwent endovascular intervention. Intervention outcomes were assessed peri-procedure and during short-term and mid-term follow-ups. Results: Of the total of 133 patients, 34.6% underwent balloon angioplasty, while 65.4% received stenting. The immediate technical success rate was 97.7%, while the clinical success rate was 62.4%. Complications were minimal, with major limb amputation reported in 1.5% of the cases. There was a significant improvement in Rutherford classification and ABI at short-term follow-up, with a patency rate of 90.2%. The mid-term post-intervention follow-up yielded similar results with an 86.1% patency rate. The mortality rates associated with arterial occlusion were 2.3% during short-term follow-up and 1.7% during mid-term follow-up. Conclusion: Balloon angioplasty and stent placement are effective and safe interventions for TASC II A and B iliac artery occlusions with favorable short and mid-term outcomes. Further, multi-center studies with larger sample sizes are recommended for more comprehensive conclusions, including long-term follow-up assessment.

3.
Infect Drug Resist ; 17: 259-273, 2024.
Article in English | MEDLINE | ID: mdl-38283112

ABSTRACT

Purpose: Staphylococcus aureus is a commensal bacteria species that can cause various illnesses, from mild skin infections to severe diseases, such as bacteremia. The distribution and antimicrobial resistance (AMR) pattern of S. aureus varies by population, time, geographic location, and hospital wards. In this study, we elucidated the epidemiology and AMR patterns of S. aureus isolated from a general hospital in Vietnam. Methods: This was a cross-sectional study. Data on all S. aureus infections from 2014 to 2021 were collected from the Microbiology department of Military Hospital 103, Vietnam. Only the first isolation from each kind of specimen from a particular patient was analyzed using the Cochran-Armitage and chi-square tests. Results: A total of 1130 individuals were diagnosed as S. aureus infection. Among them, 1087 strains were tested for AMR features. Most patients with S. aureus infection were in the age group of 41-65 years (39.82%). S. aureus isolates were predominant in the surgery wards, and pus specimens were the most common source of isolates (50.62%). S. aureus was most resistant to azithromycin (82.28%), erythromycin (82.82%), and clindamycin (82.32%) and least resistant to teicoplanin (0.0%), tigecycline (0.16%), quinupristin-dalfopristin (0.43%), linezolid (0.62%), and vancomycin (2.92%). Methicillin-resistant S. aureus (MRSA) and multidrug-resistant (MDR) S. aureus were prevalent, accounting for 73.02% and 60.90% of the total strains respectively, and the strains isolated from the intensive care unit (ICU) had the highest percentage of multidrug resistance (77.78%) among the wards. Conclusion: These findings highlight the urgent need for continuous AMR surveillance and updated treatment guidelines, particularly considering high resistance in MRSA, MDR strains, and ICU isolates. Future research focusing on specific resistant populations and potential intervention strategies is crucial to combat this rising threat.

4.
Int J STD AIDS ; 35(3): 197-205, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37967472

ABSTRACT

INTRODUCTION: We assessed trends in HIV and syphilis prevalence, HIV incidence, related risk factors, and preventive behaviors among men who have sex with men (MSM) in Vietnam from 2015 to 2020. METHODS: Data originated from the HIV Sentinel Surveillance Plus system, which sampled MSM at venues and hotspots in seven of Vietnam's 63 provinces in 2015, 2016, 2018, and 2020 (N = 1100-1445 per year; ∼150-300 per province per year). RESULTS: HIV prevalence estimates increased from 6.6% (95% CI 4.5-9.6) in 2015 to 13.8% (95% CI 10.5-18.2, p = .001 for trend) in 2020 overall, and separately in An Giang, Can Tho, Hai Phong, and Khanh Hoa provinces but not in Ho Chi Minh City, Hanoi, or Kien Giang. Syphilis prevalence increased from 2.7% (95% CI 1.4-5.1) in 2015 to 12.6% (95% CI 8.7-18.0) in 2020 overall (p < .001 for trend), and separately in An Giang, Can Tho, and Hai Phong provinces but not in Ho Chi Minh City or Kien Giang. We calculated time-at-risk from first anal sex to first HIV-positive or last HIV-negative test to estimate HIV incidence. Estimated HIV incidence suggested increasing rates of seroconversion from 1.36 per 100 person-years experienced by participants in 2015 to 2.61 per 100 person-years among participants in 2020 (hazard ratio per year 1.13, 95% CI 1.08-1.18, p < .001). There was a statistically significant increase in HIV testing, STI testing, and receipt of free condoms over the period (p < .05 for trend), and a statistically significant decrease in amphetamine use (p = .043 for trend). CONCLUSIONS: Despite prevention efforts and improvements in some risk indicators, consecutive cross-sectional sampling results provide evidence of increasing incidence of HIV and syphilis among MSM in Vietnam, especially outside the major cities. Aggressive HIV prevention and treatment services can be expanded while conducting deeper investigations into the causes of these increases.


Subject(s)
HIV Infections , Sexual and Gender Minorities , Syphilis , Male , Humans , HIV , Syphilis/epidemiology , Homosexuality, Male , Cross-Sectional Studies , Incidence , Prevalence , Vietnam/epidemiology , HIV Infections/epidemiology
5.
Asian Cardiovasc Thorac Ann ; 32(1): 5-10, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37981294

ABSTRACT

BACKGROUND: The bidirectional Glenn (BDG) shunt operation serves as temporary surgery for the treatment of single-ventricle physiology with the eventual Fontan procedure. In some cases, the procedure can be performed without the support of a cardiopulmonary bypass (CPB) machine. In this study, we present the surgical outcomes of off-pump BDG operation with the use of a temporary veno-atrial shunt to decompress the superior vena cava (SVC) during clamping time. METHODS: A cohort of 23 patients underwent off-pump BDG operations at Cardiovascular Center, E Hospital. All patients were operated on using a veno-atrial shunt to decompress the SVC. RESULTS: Satisfactory results with mean oxygen saturation increased from 79.6 ± 11.2% to 87.2 ± 4.7%. The SVC clamping time was 14 ± 2.4 min (ranging from 12 to 21 min). Among 23 patients, only six patients required blood transfusion, 17 patients had BDG without blood transfusion. No neurological complications or deaths occurred after the surgery, and the post-operative period was uneventful. CONCLUSIONS: The use of veno-atrial shunts to decompress SVC during off-pump BDG operation is safe with good surgical outcomes and can avoid the deleterious effects caused by CPB. It is easily reproducible, at low cost and economically effective.


Subject(s)
Fontan Procedure , Heart Defects, Congenital , Humans , Infant , Vena Cava, Superior/diagnostic imaging , Vena Cava, Superior/surgery , Cardiopulmonary Bypass/adverse effects , Heart Defects, Congenital/diagnostic imaging , Heart Defects, Congenital/surgery , Fontan Procedure/adverse effects , Fontan Procedure/methods , Pulmonary Artery/surgery , Treatment Outcome
6.
Arch Virol ; 169(1): 11, 2023 Dec 15.
Article in English | MEDLINE | ID: mdl-38102389

ABSTRACT

Feline panleukopenia, caused by feline parvovirus (FPV), has been studied worldwide, but there have been very few studies conducted in Vietnam. In this study, 19 rectal swab samples were collected from northern Vietnam in 2018-2019 and screened for the presence of FPV using PCR. Through sequence analysis of the full-length VP2 gene, it was found that the FPV strains detected in Vietnam were closely related to those obtained from dogs in Vietnam, Asia, Europe, and America. Moreover, the FPV strains found in Vietnam may constitute a distinct group, related to viruses sampled in China. Interestingly, most of the nucleotide changes identified were T-C substitutions.


Subject(s)
Parvoviridae Infections , Parvovirus, Canine , Cats , Animals , Dogs , Feline Panleukopenia Virus/genetics , Parvovirus, Canine/genetics , Parvoviridae Infections/epidemiology , Parvoviridae Infections/veterinary , Vietnam/epidemiology , Genetic Variation
8.
Sensors (Basel) ; 23(21)2023 Oct 26.
Article in English | MEDLINE | ID: mdl-37960447

ABSTRACT

Artificial intelligence (AI) radar technology offers several advantages over other technologies, including low cost, privacy assurance, high accuracy, and environmental resilience. One challenge faced by AI radar technology is the high cost of equipment and the lack of radar datasets for deep-learning model training. Moreover, conventional radar signal processing methods have the obstacles of poor resolution or complex computation. Therefore, this paper discusses an innovative approach in the integration of radar technology and machine learning for effective surveillance systems that can surpass the aforementioned limitations. This approach is detailed into three steps: signal acquisition, signal processing, and feature-based classification. A hardware prototype of the signal acquisition circuitry was designed for a Continuous Wave (CW) K-24 GHz frequency band radar sensor. The collected radar motion data was categorized into non-human motion, human walking, and human walking without arm swing. Three signal processing techniques, namely short-time Fourier transform (STFT), mel spectrogram, and mel frequency cepstral coefficients (MFCCs), were employed. The latter two are typically used for audio processing, but in this study, they were proposed to obtain micro-Doppler spectrograms for all motion data. The obtained micro-Doppler spectrograms were then fed to a simplified 2D convolutional neural networks (CNNs) architecture for feature extraction and classification. Additionally, artificial neural networks (ANNs) and 1D CNN models were implemented for comparative analysis on various aspects. The experimental results demonstrated that the 2D CNN model trained on the MFCC feature outperformed the other two methods. The accuracy rate of the object classification models trained on micro-Doppler features was 97.93%, indicating the effectiveness of the proposed approach.


Subject(s)
Artificial Intelligence , Radar , Humans , Signal Processing, Computer-Assisted , Walking , Fourier Analysis
9.
Clin Ter ; 174(4): 353-359, 2023.
Article in English | MEDLINE | ID: mdl-37378506

ABSTRACT

Objective: This study evaluated the effectiveness and safety of C1-C2 transarticular screw fixation (transarticular screw fixation com-bined with bone grafting) and C1 lateral mass-C2 pedicle screw fixation (modified Harms technique) in patients with C1-C2 instability. Materials and methods: This prospective, self-controlled, single-center study evaluated two fixation techniques for the treatment of atlantoaxial instability injury. From June 2006 to February 2017, 118 patients were admitted to our hospital because of atlantoaxial instability injury. These patients were divided into two groups: group 1, including 52 patients who underwent C1-C2 transarticular screw fixation (C1C2-TAS group), and group 2, including 66 patients who underwent C1 lateral mass-C2 pedicle screw fixation (C1LM-C2PS group). Results: There were significant differences in the operation time, blood loss amount, and hospital stay length between the groups (p<0.001). The mean operation time (78.94 vs. 110.91 min; p=0.0003) and hospital stay length (5.31 vs. 8.34 days; p=0.0003) were shorter, and the mean blood loss amount during surgery (122.31 vs. 258.33 mL; p<0.0001) was smaller in the C1C2-TAS group than in the C1LM-C2PS group. The surgical complication rate was low and no vertebral artery injury was observed. After surgery, the clinical presentations were significantly reduced in both groups. The patients showed sati-sfactory internal fixation on postoperative radiography and computed tomography. Conclusion: Both C1-C2 transarticular screw fixation and C1 lateral mass-C2 pedicle screw fixation are effective and safe in treat-ing atlantoaxial instability injury. Notably, C1-C2 transarticular screw fixation yields a shorter operation time and hospital stay length and a smaller intraoperative blood loss amount than does C1 lateral mass-C2 pedicle screw fixation.


Subject(s)
Joint Instability , Pedicle Screws , Spinal Fusion , Humans , Cervical Vertebrae/surgery , Prospective Studies , Spinal Fusion/methods , Joint Instability/surgery
10.
Antibiotics (Basel) ; 12(6)2023 Jun 20.
Article in English | MEDLINE | ID: mdl-37370397

ABSTRACT

Bacterial food poisoning cases due to Salmonella and E. coli O157:H7 have been linked with the consumption of a variety of food products, threatening public health around the world. This study describes the combined effects of a phage cocktail (STG2, SEG5, and PS5), EDTA, nisin, and polylysine against the bacterial cocktail consisting of S. typhimurium, S. enteritidis, and E. coli O157:H7. Overall, phage cocktail (alone or in combination with nisin or/and polylysine) not only showed great antibacterial effects against bacterial cocktail at different temperatures (4 °C, 24 °C, and 37 °C), but also totally inhibited the emergence of phage resistance during the incubation period. These results suggest that the combination of phages with nisin or/and polylysine has great potential to simultaneously control S. typhimurium, S. enteritidis, and E. coli O157:H7.

11.
Int J Food Microbiol ; 402: 110295, 2023 Oct 02.
Article in English | MEDLINE | ID: mdl-37352774

ABSTRACT

Salmonella spp., one of the most frequently reported bacteria, causes foodborne illness and economic losses. Due to the threat of increasing antibiotic resistant foodborne pathogens, application of bacteriophages as novel antibacterial agents in food matrices has become an emerging strategy. In this study, a novel Salmonella phage PS3-1 with high lytic activity against Salmonella Typhimurium was identified from previously isolated phages. PS3-1 belonged to the class Caudoviricetes with a broad host range, and had relatively short latent period (15 min), large burst size (92 PFU/cell), high pH stability (pH 3.0-11.0) and thermal tolerance (4-60 °C). Genome sequencing analysis showed that PS3-1 genome consisted of 107,110 bp DNA, without antibiotic resistance and virulence related genes. The results of growth curve and time-kill assay showed that PS3-1 not only inhibited the growth of S. Typhimurium, but also effectively decreased the viable cell counts (0.30-4.72 log) after 24-h incubation at 7, 25 and 37 °C (P < 0.05). Moreover, >1.28 log of established biofilm cells were effectively removed after 24-h treatment with PS3-1. Besides, PS3-1 significantly reduced the viability of S. Typhimurium in milk, lettuce, raw pork meat and ready-to-eat steamed-chicken breast at different temperatures (P < 0.05). These results demonstrated that PS3-1 may be an excellent antibacterial agent for controlling S. Typhimurium in food industry.


Subject(s)
Bacteriophages , Pork Meat , Red Meat , Salmonella Phages , Animals , Swine , Salmonella typhimurium , Bacteriophages/genetics , Chickens , Lactuca/microbiology , Host Specificity , Milk , Meat/microbiology , Myoviridae
12.
Pathogens ; 12(5)2023 May 16.
Article in English | MEDLINE | ID: mdl-37242391

ABSTRACT

Identifying and ensuring the inactivation of the African Swine Fever virus in deadstock is a gap in the swine industry's knowledge and response capabilities. The results of our study demonstrate that ASFv in deadstock was inactivated using static aerated composting as the carcass disposal method. Replicated compost piles with whole market hogs and two different carbon sources were constructed. In-situ bags containing ASFv-infected spleen tissue were placed alongside each of the carcasses and throughout the pile. The bags were extracted at days 0, 1, 3, 7, 14, 28, 56, and 144 for ASFv detection and isolation. Real-time PCR results showed that DNA of ASFv was detected in all samples tested on day 28. The virus concentration identified through virus isolation was found to be below the detection limit by day 3 in rice hulls and by day 7 in sawdust. Given the slope of the decay, near-zero concentration with 99.9% confidence occurred at 5.0 days in rice hulls and at 6.4 days in sawdust. Additionally, the result of virus isolation also showed that the virus in bone marrow samples collected at 28 days was inactivated.

13.
Pathogens ; 12(4)2023 Apr 21.
Article in English | MEDLINE | ID: mdl-37111514

ABSTRACT

African swine fever (ASF) is a highly contagious swine disease with high mortality. In many countries, culling pigs infected and exposed to the ASF virus is mandatory to control the disease, which poses a real challenge in the disposal of large numbers of carcasses during ASF outbreaks. Shallow burial with carbon (SBC) Thanks ew mortality disposal method developed from deep burial and composting. The present study investigates the effectiveness of SBC in disposing of ASF virus-infected pigs. The real-time PCR results showed that DNA of the ASF virus was still detected in bone marrow samples on day 56, while the virus isolation test revealed that the infectious ASF virus was destroyed in both spleen and bone marrow samples on day 5. Interestingly, decomposition was found to occur rapidly in these shallow burial pits. On day 144, only large bones were found in the burial pit. In general, the results of this study indicated that SBC is a potential method for the disposal of ASF-infected carcasses; however, further studies are needed to provide more scientific evidence for the efficacy of SBC in different environment conditions.

14.
J Gen Appl Microbiol ; 68(6): 262-269, 2023 Mar 06.
Article in English | MEDLINE | ID: mdl-35781262

ABSTRACT

From the biotechnological point of view, enzymes are powerful tools that help sustain a clean environment in several ways. The enzymatic biodegradation of synthetic dyes is a promising goal since it reduces pollution caused by textile dyeing factory wastewater. Lignin peroxidase (EC 1.11.1.14, LiP) has high redox potential; thus, it is great for application in various industrial fields (e.g., paper- waste treatment and textile dyeing wastewater treatment). In the present study, a LiP from an isolated strain Pleurotus pulmonarius CPG6 (PpuLiP) was successfully purified with a specific activity of 6.59 U mg -1. The enzyme was purified by using three-step column chromatography procedures including DEAE, Sephadex G-75, and HiTrapTM Q FF columns with 17.8-fold purity. The enzyme with a molecular weight of 40 kDa exhibited enhanced pH stability in the acidic range. The activity retention was over 75% at a pH of 3.0 for more than 6 hours. Purified PpuLiP was able to oxidize a variety of substrates including veratryl alcohol, 2,4-DCP, n propanol, and guaiacol. The effect of metal ions on PpuLiP activity was analyzed. The study will provide a ground to decolorize dyes from various groups of PpuLiP. Purified PpuLiP could decolorize 35% Acid blue 25 (AB25), 50% Acid red 129 (AB129), 72% Acid blue 62 (NY3), 85% Acid blue 113 (AB113), 55% Remazol Brilliant blue R (RBBR), and 100% Reactive red 120 (RR120) for 12 hours. Most of the dyes were decolorized, but the heat-denatured enzyme used as negative control obviously did not decolorize the tested dyes. These results indicate that the PpuLiP has potential application in enzyme-based decolorization of synthetic dyes. Keywords: Decolorization; lignin peroxidase; Pleurotus pulmonarius; textile dyes.


Subject(s)
Pleurotus , Pleurotus/metabolism , Biodegradation, Environmental , Coloring Agents/analysis , Coloring Agents/chemistry , Coloring Agents/metabolism , Textiles , Laccase/metabolism
15.
Int J Food Microbiol ; 385: 109999, 2023 Jan 16.
Article in English | MEDLINE | ID: mdl-36335891

ABSTRACT

As one major foodborne pathogen, Salmonella can cause serious food poisoning outbreaks worldwide. Bacteriophage therapy is increasingly considered as one of the promising antibacterial agents for the biocontrol of foodborne pathogens. In the current study, a lytic phage STG2 capable of infecting S. enteritidis and S. typhimurium was characterized, and its efficacy in reducing these foodborne pathogens in both planktonic and biofilm forms was evaluated on cabbage and various surfaces. Genomic characterization revealed that phage STG2 was Siphoviridae phage (Epseptimavirus genus) with a dsDNA genome comprising of 114,275 bp and its genome does not contain any genes associated to antibiotic resistance, toxins, lysogeny, or virulence factors. Additionally, phage STG2 exhibited great efficacy in reducing (>2 Log) planktonic cells on cabbage as well as the biofilms formed on cabbage, polystyrene, and stainless steel, suggesting that phage STG2 is capable of simultaneously controlling both S. enteritidis and S. typhimurium contaminations on food and food-related surfaces.


Subject(s)
Bacteriophages , Salmonella Phages , Salmonella Phages/genetics , Bacteriophages/genetics , Plankton/genetics , Salmonella enteritidis , Biofilms , Genomics
16.
Res Vet Sci ; 153: 105-114, 2022 Dec 31.
Article in English | MEDLINE | ID: mdl-36347064

ABSTRACT

Canine distemper virus (CDV) is a pathogen causing fatal disease in a wide range of carnivores. Sequence analysis of CDV strains has been classified into several geographically-related lineages, and the evolution and emergence of these strains are not fully yet investigated. In this study, the complete H gene sequences of 15 CDV strains isolated on Vero DST cell culture from clinical samples of vaccinated domestic dogs in Vietnam were investigated. Fifteen CDV isolates belonging to Asia-1 CDV variants were predominant antigenic type circulated in Central and Northern Vietnam with notable differences regarding the region and some genetic variation, and the most closely related Asia-1 variants lineage reported in Vietnam, China, Taiwan, and Japan. All identified CDV isolates clustered into 2 novel clades Asia-1-C1 and Asia-1-C2. The major amino acid mutation variants of Vietnamese Asia-1 CDV strains were found at sites 51, 157, 159, 160, 171, 178, 186, 235, 245, 277, 288, 313, 324, 330, 337, 345, 358, 359, 365, 383, 446, 475, 517, 530, 584, 598 which include N-glycosylation sites and neutralizing epitope regions in H gene. The results of the virus neutralization titer (VNT) assay showed that the dogs vaccinated with commercial vaccines had significantly low VNT (4.89 and 12.8) against field CDV isolate strains (VNUA NA04, HN18, and NB05) isolated in northern and central Vietnam, respectively. These data may suggest the need for further research in CDV monitoring and development of preventative measures against CDV in Vietnam.

17.
Transbound Emerg Dis ; 69(5): e3036-e3044, 2022 Sep.
Article in English | MEDLINE | ID: mdl-35830975

ABSTRACT

African swine fever (ASF) has been considered as one of the most important and devastating swine diseases with high mortality rates. Since effective vaccines and treatment are not available, mass euthanasia of infected and exposed pigs has been known to be the best measure to control ASF. Although composting has been proved to be a safe method for the rapid disposal of animal carcasses during outbreaks, there is no information about the effect of composting on the viability of ASF virus in swine carcasses. This study investigates the survival of the ASF virus in swine carcasses during composting. The findings suggested that the DNA of the ASF virus was detected in all samples tested. On the contrary, infectious ASF virus particles were rapidly destroyed at day 3.


Subject(s)
African Swine Fever Virus , African Swine Fever , Composting , Swine Diseases , Vaccines , African Swine Fever Virus/genetics , Animals , Disease Outbreaks , Sus scrofa , Swine
18.
PLoS Negl Trop Dis ; 15(12): e0010017, 2021 12.
Article in English | MEDLINE | ID: mdl-34898620

ABSTRACT

The epidemiology of typhoid fever in Lao People`s Democratic Republic is poorly defined. Estimating the burden of typhoid fever in endemic countries is complex due to the cost and limitations of population-based surveillance; serological approaches may be a more cost-effective alternative. ELISAs were performed on 937 serum samples (317 children and 620 adults) from across Lao PDR to measure IgG antibody titers against Vi polysaccharide and the experimental protein antigens, CdtB and HlyE. We measured the significance of the differences between antibody titers in adults and children and fitted models to assess the relationship between age and antibody titers. The median IgG titres of both anti-HylE and CdtB were significantly higher in children compared to adults (anti-HylE; 351.7 ELISA Units (EU) vs 198.1 EU, respectively; p<0.0001 and anti-CdtB; 52.6 vs 12.9 EU; p<0.0001). Conversely, the median anti-Vi IgG titer was significantly higher in adults than children (11.3 vs 3.0 U/ml; p<0.0001). A non-linear trend line fitted to the anti-CdtB and anti-HlyE IgG data identified a peak in antibody concentration in children <5 years of age. We identified elevated titers of anti-HlyE and anti-CdtB IgG in the serum of children residing in Lao PDR in comparison to adults. These antigens are associated with seroconversion after typhoid fever and may be a superior measure of disease burden than anti-Vi IgG. This approach is scalable and may be developed to assess the burden of typhoid fever in countries where the disease may be endemic, and evidence is required for the introduction of typhoid vaccines.


Subject(s)
Antigens, Bacterial/blood , Salmonella typhi/immunology , Typhoid Fever/blood , Adolescent , Adult , Age Factors , Antibodies, Bacterial/blood , Child , Child, Preschool , Cohort Studies , Enzyme-Linked Immunosorbent Assay , Female , Humans , Immunoglobulin G/blood , Infant , Laos/epidemiology , Male , Salmonella typhi/genetics , Typhoid Fever/epidemiology , Typhoid Fever/microbiology , Young Adult
19.
FEMS Microbiol Lett ; 368(16)2021 09 01.
Article in English | MEDLINE | ID: mdl-34415008

ABSTRACT

Chitinases are enzymes that catalyze the degradation of chitin, a major component of the cell walls of pathogenic fungi and cuticles of insects, gaining increasing attention for the control of fungal pathogens and insect pests. Production of recombinant chitinase in a suitable host can result in a more pure product with less processing time and a significantly larger yield than that produced by native microorganisms. The present study aimed to express the synthetic chi42 gene (syncodChi42), which was optimized from the chi42 gene of Trichoderma asperellum SH16, in Escherichia coli to produce 42 kDa chitinase (Ta-CHI42); then determined the activity of this enzyme, characterizations and in vitro antifungal activity as well as its immunogenicity in mice. The results showed that Ta-CHI42 was overexpressed in E. coli. Analysis of the colloidal chitin hydrolytic activity of purified Ta-CHI42 on an agar plate revealed that this enzyme was in a highly active form. This is a neutral chitinase with pH stability in a range of 6-8 and has an optimum temperature of 45°C with thermal stability in a range of 25-35°C. The chitinolytic activity of Ta-CHI42 was almost completely abolished by 5 mM Zn2+ or 1% SDS, whereas it remained about haft under the effect of 1 M urea, 1% Triton X-100 or 5 mM Cu2+. Except for ions such as Mn2+ and Ca2+ at 5 mM that have enhanced chitinolytic activity; 5 mM of Na+, Fe2+ or Mg2+ ions or 1 mM EDTA negatively impacted the enzyme. Ta-CHI42 at 60 U/mL concentration strongly inhibited the growth of the pathogenic fungus Aspergillus niger. Analysis of western blot indicated that the polyclonal antibody against Ta-CHI42 was greatly produced in mice. It can be used to analyze the expression of the syncodChi42 gene in transgenic plants, through immunoblotting assays, for resistance to pathogenic fungi.


Subject(s)
Chitinases , Gene Expression , Hypocreales , Animals , Chitin/metabolism , Chitinases/genetics , Chitinases/metabolism , Escherichia coli/genetics , Genes, Synthetic/genetics , Hypocreales/enzymology , Hypocreales/genetics , Mice
20.
Food Microbiol ; 100: 103853, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34416958

ABSTRACT

The combined effects of ethylenediaminetetraacetic acid (EDTA) and bacteriophage (phage) treatment of foodborne pathogens were investigated. Although viable counts for Campylobacter jejuni decreased by 1.5 log after incubation for 8 h in the presence of phage PC10, re-growth was observed thereafter. The combination of phage PC10 and 1 mM EDTA significantly inhibited the re-growth of C. jejuni. The viable counts for C. jejuni decreased by 2.6 log (P < 0.05) compared with that of the initial count after 24 h. Moreover, EDTA at 0.67 or 1.3 mM, combined with the specific lytic phages, also effectively inhibited the re-growth of phage-resistant cells of Campylobacter coli, Salmonella enterica serovar Enteritidis, and Salmonella enterica serovar Typhimurium. In addition, the combined effects of lytic phages and EDTA were investigated on the viability of Campylobacter in BHI broth at low temperatures followed by the optimum growth temperature. The re-growth of C. coli was significantly inhibited by the coexistence of 1.3 mM EDTA, and the viable counts of surviving bacteria was about the same as the initial viable count after the incubation. This is the first study demonstrating the combined use of lytic phages and EDTA is effective in inhibiting the re-growth of phage-resistant bacteria in Gram-negative bacteria.


Subject(s)
Bacteriophages/physiology , Campylobacter coli/growth & development , Campylobacter jejuni/growth & development , Edetic Acid/pharmacology , Salmonella enteritidis/growth & development , Salmonella typhimurium/growth & development , Campylobacter coli/drug effects , Campylobacter coli/virology , Campylobacter jejuni/drug effects , Campylobacter jejuni/virology , Microbial Viability , Salmonella enteritidis/drug effects , Salmonella enteritidis/virology , Salmonella typhimurium/drug effects , Salmonella typhimurium/virology
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