38 research outputs found

    Poultry and Beef Meat as Potential Seedbeds for Antimicrobial Resistant Enterotoxigenic Bacillus Species: A Materializing Epidemiological and Potential Severe Health Hazard

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    Although Bacillus cereus is of particular concern in food safety and public health, the role of other Bacillus species was overlooked. Therefore, we investigated the presence of eight enterotoxigenic genes, a hemolytic gene and phenotypic antibiotic resistance profiles of Bacillusspecies in retail meat samples. From 255 samples, 124 Bacillus isolates were recovered, 27 belonged to B. cereusand 97 were non-B. cereus species. Interestingly, the non-B. cereus isolates carried the virulence genes and exhibited phenotypic virulence characteristics as the B. cereus. However, correlation matrix analysis revealed the B. cereus group positively correlates with the presence of the genes hblA, hblC, and plc, and the detection of hemolysis (p \u3c 0.05), while the other Bacillus sp. groups are negatively correlated. Tests for antimicrobial resistance against ten antibiotics revealed extensive drug and multi-drug resistant isolates. Statistical analyses didn’t support a correlation of antibiotic resistance to tested virulence factors suggesting independence of these phenotypic markers and virulence genes. Of special interest was the isolation of Paenibacillus alvei and Geobacillus stearothermophilus from the imported meat samples being the first recorded. The isolation of non-B. cereus species carrying enterotoxigenic genes in meat within Egypt, suggests their impact on food safety and public health and should therefore not be minimised, posing an area that requires further research

    Immunoinformatics and reverse vaccinology approach in designing a novel highly immunogenic multivalent peptide-based vaccine against the human monkeypox virus

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    Background: Monkeypox is a highly infectious zoonotic disease, often resulting in complications ranging from respiratory illnesses to vision loss. The escalating global incidence of its cases demands prompt attention, as the absence of a proven post-exposure treatment underscores the criticality of developing an effective vaccine.Methods: Interactions of the viral proteins with TLR2 and TLR4 were investigated to assess their immunogenic potentials. Highly immunogenic proteins were selected and subjected to epitope mapping for identifying B-cell and MHC class I and II epitopes. Epitopes with high antigenicity were chosen, considering global population coverage. A multi-target, multi-epitope vaccine peptide was designed, incorporating a beta-defensin 2 adjuvant, B-cell epitopes, and MHC class I and II epitopes.Results: The coordinate structure of the engineered vaccine was modeled and validated. In addition, its physicochemical properties, antigenicity, allergenicity, and virulence traits were evaluated. Molecular docking studies indicated strong interactions between the vaccine peptide and the TLR2 receptor. Furthermore, molecular dynamics simulations and immune simulation studies reflected its potent cytosolic stability and robust immune response dynamics induced by the vaccine.Conclusion: This study explored an innovative structure-guided approach in the use of immunoinformatics and reverse vaccinology in pursuit of a novel multi-epitope vaccine against the highly immunogenic monkeypox viral proteins. The simulation studies indicated the engineered vaccine candidate to be promising in providing prophylaxis to the monkeypox virus; nevertheless, further in vitro and in vivo investigations are required to prove its efficacy

    The Potential Link between Thermal Resistance and Virulence in Salmonella: A Review

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    In some animals, the typical body temperature can be higher than humans, for example, 42°C in poultry and 40°C in rabbits which can be a potential thermal stress challenge for pathogens. Even in animals with lower body temperatures, when infection occurs, the immune system may increase body temperature to reduce the chance of survival for pathogens. However, some pathogens can still easily overcome higher body temperatures and/or rise in body temperatures through expression of stress response mechanisms. Salmonella is the causative agent of one of the most prevalent foodborne illnesses, salmonellosis, and can readily survive over a wide range of temperatures due to the efficient expression of the heat (thermal) stress response. Therefore, thermal resistance mechanisms can provide cross protection against other stresses including the non-specific host defenses found within the human body thus increasing pathogenic potential. Understanding the molecular mechanisms associated with thermal responses in Salmonella is crucial in designing and developing more effective or new treatments for reducing and eliminating infection caused by Salmonella that have survived heat stress. In this review, Salmonella thermal resistance is assessed followed by an overview of the thermal stress responses with a focus on gene regulation by sigma factors, heat shock proteins, along with the corresponding thermosensors and their association with virulence expression including a focus on a potential link between heat resistance and potential for infection

    Bacillus thuringiensis PM25 ameliorates oxidative damage of salinity stress in maize via regulating growth, leaf pigments, antioxidant defense system, and stress responsive gene expression

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    Soil salinity is the major abiotic stress that disrupts nutrient uptake, hinders plant growth, and threatens agricultural production. Plant growth-promoting rhizobacteria (PGPR) are the most promising eco-friendly beneficial microorganisms that can be used to improve plant responses against biotic and abiotic stresses. In this study, a previously identified B. thuringiensis PM25 showed tolerance to salinity stress up to 3 M NaCl. The Halo-tolerant Bacillus thuringiensis PM25 demonstrated distinct salinity tolerance and enhance plant growth-promoting activities under salinity stress. Antibiotic-resistant Iturin C (ItuC) and bio-surfactant-producing (sfp and srfAA) genes that confer biotic and abiotic stresses were also amplified in B. thuringiensis PM25. Under salinity stress, the physiological and molecular processes were followed by the over-expression of stress-related genes (APX and SOD) in B. thuringiensis PM25. The results detected that B. thuringiensis PM25 inoculation substantially improved phenotypic traits, chlorophyll content, radical scavenging capability, and relative water content under salinity stress. Under salinity stress, the inoculation of B. thuringiensis PM25 significantly increased antioxidant enzyme levels in inoculated maize as compared to uninoculated plants. In addition, B. thuringiensis PM25-inoculation dramatically increased soluble sugars, proteins, total phenols, and flavonoids in maize as compared to uninoculated plants. The inoculation of B. thuringiensis PM25 significantly reduced oxidative burst in inoculated maize under salinity stress, compared to uninoculated plants. Furthermore, B. thuringiensis PM25-inoculated plants had higher levels of compatible solutes than uninoculated controls. The current results demonstrated that B. thuringiensis PM25 plays an important role in reducing salinity stress by influencing antioxidant defense systems and abiotic stress-related genes. These findings also suggest that multi-stress tolerant B. thuringiensis PM25 could enhance plant growth by mitigating salt stress, which might be used as an innovative tool for enhancing plant yield and productivity

    Isolation, identification, and characterization of resistant bacteria to antibiotics from pharmaceutical effluent and study of their antibiotic resistance

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    Pharmaceutical effluents primarily enter aquatic environments through the discharge of treated and untreated wastewater from various sources, including hospitals, pharmaceutical manufacturing facilities, and households. Microbes sourced from pharmaceutical effluents such as Pseudomonas spp. pose a significant public health concern because of their high levels of resistance to multiple drugs and extreme multidrug resistance. Therefore, the present study was conducted for the isolation, identification, and molecular characterization of selected isolates from pharmaceutical effluents and also determined their antibiotic sensitivity patterns. From June 2016 to March 2017, a study was conducted on four well-known pharmaceutical companies specializing in antibiotic production in Dhaka and Gazipur. Four wastewater samples were collected from various origins and then brought to the Bacteriology laboratory for microbiological examination. Twelve pure isolates were obtained and characterized through cultural and biochemical tests while molecular identification of Pseudomonas spp. was performed using the 16S rRNA gene sequence. Twelve commercially available antibiotics were used for antibiotic sensitivity tests using Kirby-Bauer disk diffusion methods. We isolated the most predominant isolates, Pseudomonas aeruginosa (41.67%), followed by Bacillus spp. (33.33%) and Staphylococcus spp. (25%) respectively. Among 12 antibiotics, ciprofloxacin is 100% sensitive against P. aeruginosa, while the remaining 11 antibiotics are 100% resistant. Bacillus spp. showed 100% resistance to all antibiotics while 50% sensitive to vancomycin and 100% to chloramphenicol, respectively. Staphylococcus spp. was 100% resistant to all antibiotics. Our research suggested that P. aeruginosa is the reservoir of antibiotic resistance genes and spreads disease to humans from the environment. The findings of this study, i.e., the isolation, identification, and characterization of antibiotic-resistant bacteria from pharmaceutical effluent have highlighted, comprehended, and mitigated the dissemination of antibiotic resistance and opportunistic bacteria

    Production, optimization, and physicochemical characterization of biodiesel from seed oil of indigenously grown Jatropha curcas

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    With the growing demand for vegetable oils, alternative non-edible feedstocks like Jatropha curcas seed oil have gained interest for biodiesel production. The study aimed to comprehensively evaluate the physicochemical properties and biodiesel production potential of locally produced J. curcas seeds in Pakistan. Two different approaches were applied: a chemical synthesis approach involving acidic pretreatment and alkaline transesterification, and a biosynthetic approach using a lipase-producing strain of the Bacillus subtilis Q5 strain. The microbial biosynthesized biodiesel was further optimized using the Plackett–Burman design. The physicochemical properties of the J. curcas methyl esters were analyzed to assess their suitability as biodiesel fuel. Initially, the raw oil had a high free fatty acid content of 13.11%, which was significantly reduced to 1.2% using sulfuric acid pretreatment, keeping the oil to methanol molar ratio to be 1:12. Afterward, alkaline transesterification of purified acid-pretreated seed oil resulted in 96% biodiesel yield at an oil to methanol molar ratio of 1:6, agitation of 600 revolutions per minute (RPM), temperature 60°C, and time 2 h. Moreover, alkaline transesterification yielded ∼98% biodiesel at the following optimized conditions: oil to methanol molar ratio 1:6, KOH 1%, time 90 min, and temperature 60°C. Similarly, the Bacillus subtilis Q5 strain yielded ∼98% biodiesel at the following optimized conditions: oil: methanol ratio of 1:9, agitation 150 RPM, inoculum size 10%, temperature 37°C, and n-hexane 10%. The fuel properties of J. curcas seed biodiesel are closely related to standard values specified by the American Society for Testing and Materials (ASTM D6751–20a), indicating its potential as a viable biodiesel fuel source

    Integrative Taxonomy of Novel <i>Diaporthe</i> Species Associated with Medicinal Plants in Thailand

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    During our investigations of the microfungi on medicinal plants in Thailand, five isolates of Diaporthe were obtained. These isolates were identified and described using a multiproxy approach, viz. morphology, cultural characteristics, host association, the multiloci phylogeny of ITS, tef1-α, tub2, cal, and his3, and DNA comparisons. Five new species, Diaporthe afzeliae, D. bombacis, D. careyae, D. globoostiolata, and D. samaneae, are introduced as saprobes from the plant hosts, viz. Afzelia xylocarpa, Bombax ceiba, Careya sphaerica, a member of Fagaceae, and Samanea saman. Interestingly, this is the first report of Diaporthe species on these plants, except on the Fagaceae member. The morphological comparison, updated molecular phylogeny, and pairwise homoplasy index (PHI) analysis strongly support the establishment of novel species. Our phylogeny also revealed the close relationship between D. zhaoqingensis and D. chiangmaiensis; however, the evidence from the PHI test and DNA comparison indicated that they are distinct species. These findings improve the existing knowledge of taxonomy and host diversity of Diaporthe species as well as highlight the untapped potential of these medicinal plants for searching for new fungi

    Antimicrobial activity of some plant extracts against bacterial strains causing food poisoning diseases

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    Prevention of food spoilage and food poisoning pathogens is usually achieved by use of chemical preservatives which have negative impacts including: human health hazards of the chemical applications, chemical residues in food & feed chains and acquisition of microbial resistance to the used chemicals. Because of such concerns, the necessity to find a potentially effective, healthy safer and natural alternative preservatives is increased. Within these texts, Plant extracts have been used to control food poisoning diseases and preserve foodstuff. Antimicrobial activity of five plant extracts were investigated against Bacillus cereus, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi using agar disc diffusion technique. Ethanolic extracts of Punica granatum, Syzygium aromaticum, Zingiber officinales and Thymus vulgaris were potentially effective with variable efficiency against the tested bacterial strains at concentration of 10 mg/ml while extract of Cuminum cyminum was only effective against S. aureus respectively. P. granatum and S. aromaticum ethanolic extracts were the most effective plant extracts and showed bacteriostatic and bactericidal activities against the highly susceptible strains of food borne pathogenic bacteria (S. aureus and P. aeruginosa) with MIC's ranged from 2.5 to 5.0 mg/ml and MBC of 5.0 and 10 mg/ml except P. aeruginosa which was less sensitive and its MBC reached to 12.5 mg/ml of S. aromaticum respectively. These plant extracts which proved to be potentially effective can be used as natural alternative preventives to control food poisoning diseases and preserve food stuff avoiding healthy hazards of chemically antimicrobial agent applications

    Prevalence of Multidrug-Resistant Bacteria in Healthcare-Associated Bloodstream Infections at Hospitals in Riyadh, Saudi Arabia

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    Bloodstream infection (BSI) prevalence in hospitalized patients has increased owing to the spread of antibiotic-resistant pathogens; moreover, antimicrobial resistance in bacteria is a global problem. Here, BSIs are investigated in several patients at a hospital in Saudi Arabia, and the resistance of bacterial isolates to widely used drugs is determined. Throughout 2020, bacteria isolated from patients were identified and subjected to antibiotic susceptibility testing. In total, 1125 bacterial isolates were obtained from 1039 patients; among them, gram-positive bacteria were significantly more abundant than gram-negative bacteria. The most prevalent bacteria were Staphylococcus epidermidis and Klebsiella pneumoniae. Notably, gram-negative bacteria were mainly isolated from adult patients, and 20.63% of the gram-positive isolates were from pediatric patients, which was significantly higher than the corresponding percentages in elders and adults. The gram-positive isolates were mainly resistant to cephalothin, oxacillin, amoxicillin-clavulanate, and erythromycin and susceptible to penicillin, gentamicin, ciprofloxacin, and vancomycin. Additionally, the gram-negative isolates were mainly resistant to ampicillin, cephalothin, and amoxicillin-clavulanate and susceptible to amikacin, ertapenem, aztreonam, colistin, and trimethoprim-sulfamethoxazole. Consequently, the high prevalence of infective multidrug-resistant bacteria may account as a significant health issue; it is considered a hazard in Riyadh hospitals and must be prevented at all costs

    Molecular characterization of the capsular antigens of Pasteurella multocida isolates using multiplex PCR

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    The use of molecular techniques for detection and characterization of the Pasteurella multocida is very important for rapid and specific detection and characterization of the organism. During the period from 15th February, 2014 to 15th April, 2015, 425 nasopharyngeal swabs and 175 lung and spleen samples were collected and examined by conventional methods, 80 strains (18.82%) of P. multocida were isolated from the calves, sheep and goat with respiratory manifestation. Meanwhile, 77 strains (44%) were isolated from emergency slaughtered animals. All the recovered strains were positive for specific PCR for detection of P. multocida strains previously identified as P. multocida by standard microbiological techniques. Multiplex PCR for molecular typing of the capsular antigens of the recovered P. multocida revealed positive amplification of 1044 bp fragments specific to the capsular antigen type A with 105 strains (66.88%), and amplification 511 bp fragments of the capsular antigen type E with 52 strain (33.12%) and absence of B, D and F antigens. Multiplex PCR for molecular typing of the capsular antigens of P. multocida can be used as a simple, sensitive, rapid, reliable technique instead of the serological techniques for identification of the capsular antigens of P. multocid
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