scholarly journals Update on molecular diversity and multipathogenicity of staphylococcal superantigen toxins

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Dong-Liang Hu ◽  
Shaowen Li ◽  
Rendong Fang ◽  
Hisaya K. Ono

AbstractStaphylococcal superantigen (SAg) toxins are the most notable virulence factors associated with Staphylococcus aureus, which is a pathogen associated with serious community and hospital acquired infections in humans and various diseases in animals. Recently, SAg toxins have become a superfamily with 29 types, including staphylococcal enterotoxins (SEs) with emetic activity, SE-like toxins (SEls) that do not induce emesis in primate models or have yet not  been tested, and toxic shock syndrome toxin-1 (TSST-1). SEs and SEls can be subdivided into classical types (SEA to SEE) and novel types (SEG to SElY, SE01, SE02, SEl26 and SEl27). The genes of SAg toxins are located in diverse accessory genetic elements and share certain structural and biological properties. SAg toxins are heat-stable proteins that exhibit pyrogenicity, superantigenicity and capacity to induce lethal hypersensitivity to endotoxin in humans and animals. They have multiple pathogenicities that can interfere with normal immune function of host, increase the chances of survival and transmission of pathogenic bacteria in host, consequently contribute to the occurrence and development of various infections, persistent infections or food poisoning. This review focuses on the following aspects of SAg toxins: (1) superfamily members of classic and novelty discovered staphylococcal SAgs; (2) diversity of gene locations and molecular structural characteristics; (3) biological characteristics and activities; (4) multi-pathogenicity of SAgs in animal and human diseases, including bovine mastitis, swine sepsis, abscesses and skin edema in pig, arthritis and septicemia in poultry, and nosocomial infections and food-borne diseases in humans.

PRILOZI ◽  
2020 ◽  
Vol 41 (3) ◽  
pp. 49-57
Author(s):  
Fatah B Ahtesh ◽  
Lily Stojanovska ◽  
Jack Feehan ◽  
Maximilian PJ de Courten ◽  
Matthew Flavel ◽  
...  

AbstractPlants that are primarily used as a food source commonly have undervalued biological properties beyond the basic supply of nutrients. One important example of this are the antimicrobial properties of plants. Inclusion of natural and food grade antimicrobial ingredients in recipes to prevent food spoilage and disease transmission, or in cosmetic products to prevent transient and pathogenic bacteria would have world-wide public health implications. A patented natural polyphenol rich sugar cane extract (PRSE), is marketed as a high anti-oxidant and polyphenol ingredient, but its anti-microbial activity has not been reported previously. We determined the anti-bacterial properties of PRSE on common human pathogens relating to a range of diseases including food poisoning, tooth decay, acne and severe skin infections using disc/well diffusion experiments. Our findings indicate that PRSE is an efficient antimicrobial, which could be included at differing dosages to target a range of food borne and environmental pathogens.


2014 ◽  
Vol 8 (11) ◽  
pp. 1407-1414 ◽  
Author(s):  
Laila Nimri ◽  
Fatina Abu AL- Dahab ◽  
Raymond Batchoun

Introduction: The purpose of the study was to isolate, identify, and determine the antimicrobial resistance of the bacterial pathogens recovered from shawarma (donair) sandwiches served to the public in Jordan. Methodology: Bacterial contamination of 100 shawarma sandwiches with pathogenic bacteria was studied by culture on selective media, serology, PCR assay, and antimicrobial susceptibility testing. Results: One hundred and forty-five bacterial isolates were identified. The predominant species was Escherichia coli (28.3%), with six isolates of serotype O157:H7, followed by Salmonella spp. (25.5%). Higher contamination rates were found in chicken sandwiches. The majority of these bacteria expressed high resistance to several antimicrobials, especially tetracycline and streptomycin. Citrobacter freundii was isolated from 15.9% and Staphylococcus aureus was isolated from 8.3% of the sandwiches. The presence of these pathogens is of primary concern because some strains are capable of producing a heat-stable enterotoxin that causes food poisoning in humans, and should therefore be taken into account in risk assessment. Conclusions: Results signify the importance of sustained surveillance of foodborne pathogens in shawarma sandwiches to minimize the risk of contamination. Availability of data on the isolated pathogens and modes of transmission in food from different countries would provide a common ground for reaching international agreement on food safety regulations.


Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 734
Author(s):  
Wioleta Chajęcka-Wierzchowska ◽  
Joanna Gajewska ◽  
Patryk Wiśniewski ◽  
Anna Zadernowska

Although coagulase-positive staphylococci are considered to be the main factor responsible for food poisoning, an increasing role for the coagulase-negative staphylococci in the production of enterotoxins has been observed in recent years. This study was conducted to assess the occurrence of genes responsible for the production of staphylococcal enterotoxins (SE), enterotoxin-like toxins (SEI) and toxic shock syndrome toxin-1 (TSST-1) in coagulase-negative staphylococci (CoNS) isolated from ready-to-eat food from bars and restaurants. One hundred and eighteen CoNS strains were tested using polymerase chain reaction (PCR) to five superantigenic toxin genes, including five different types of classical enterotoxins (sea, seb, sec, sed and see) and the toxic shock syndrome toxin-1 (tsst-1) as well as to supertoxin-like genes. PCR-positive isolates were then tested using immunoenzymatic methods (SET-RPLA, Vidas SET 2) for toxin expression. Out of 118 CoNS strains, the presence of staphylococcal enterotoxins was confirmed in 72% of them. The most frequently found enterotoxin-like genotype was ser, selu. Two of the tested strains had up to ten different enterotoxin genes in the genome at the same time. Although no production of enterotoxins was detected in the CoNS, which means that their possible role in the epidemiology of food-borne diseases is minimal, the data demonstrated that the toxigenic capacity of the CoNS should not be ignored, and that this group of microorganisms should be continuously monitored in food.


1979 ◽  
Vol 83 (1) ◽  
pp. 33-40 ◽  
Author(s):  
M.-L. Danielsson ◽  
R. Möllby ◽  
H. Brag ◽  
N. Hansson ◽  
P. Jonsson ◽  
...  

SUMMARYAll of 86 foods routinely examined for potentially pathogenic enteric bacteria were found to harbour one or more coliform species. None of the strains isolated produced heat-labile enterotoxin (LT) or showed invasive properties. The suckling mouse test indicated that one strain ofEscherichia coliproduced heat-stable enterotoxin (ST). Twelve incidents of suspected food poisoning were also investigated. In two of them the foods examined contained LT-producing strains ofE. coliand in two there were LT-producing strains ofKlebsiella pneumoniae. The counts of viable enterotoxigenic micro-organisms in these foods were 3000–30 000E. coli/g and 50 000 to 1 millionK. pneumoniae/g. The dominant symptom in all the incidents was watery diarrhoea. These seem to be the first reported cases of foodborne enterotoxigenic enteric bacteria in Europe. Though enterotoxigenicE. coliand related gram-negative enterotoxin-producing species are rare in correctly handled food in Sweden, these micro-organisms should be searched for when outbreaks of food poisoning are investigated.


2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Mahsa Abbasi ◽  
Samaneh Dolatabadi ◽  
Ghazaleh Ghorbannezhad ◽  
Fatemeh Sharifi ◽  
Hamid Reza Rahimi

ABSTRACTMethicillin-resistant Staphylococcus aureus (MRSA) is a hospital-acquired pathogen with high prevalence across the globe. It raises a serious health concern due to its resistance to antibiotic agents, in particular, β-lactam, carbapenem, and penem. This pathogen causes various medical conditions, namely endocarditis, osteomyelitis, pneumonia, toxic shock syndrome (TSS), and food poisoning. Strains of lactic acid bacteria (LAB) such as Lactobacillus sp. and Bifidobacterium sp. inhibit pathogenic bacteria through competition for nutrients and adhesion sites, production of antimicrobial substances, and enhancement of immune system. The present hypothesis describes that these probiotics prevent the growth of MRSA by producing inhibitory agents like bacteriocin, lactic acid, acetic acid, propionic acid, hydrogen peroxide, and the intestinal pH reduction. Given an increasing resistance to antibiotics and its adverse effects, the use of other alternatives seems necessary. These beneficial bacteria and their metabolites which are available in the market as tablets, capsules, and powders can widely establish control over the growth of MRSA.


Author(s):  
Malireddy S Reddy

The worldwide popularity of Dr. M.S. Reddy’s Multiple Mixed Strain Probiotic Therapy to treat or prevent the hospital acquired infections (nosocomial infections) arose a great interest in the medical community around the world (Reddy and Reddy, 2016; 2017). The following questions were raised on this subject: Does Multiple Mixed Strain Probiotics directly inhibit the pathogenic bacteria (C. diff) in the gastrointestinal tract or indirectly through modulation of the host immune system or both? To be more specific, what is the exact and/or hypothetical mechanism at molecular level behind the breakthrough discovery of Dr. M.S. Reddy’s Multiple Mixed Strain Probiotic Therapy?  To answer these questions, the specific immunomodulation regulatory functions of the individual Probiotic strains (on host) have beenresearched, investigated andoutlined in this article.  A detailed explanation(s) and hypotheses have been proposed outlining the possible cumulativedirect bacteriological and indirect immunomodulatory effects (at the molecular level) of the Multiple Mixed Strain Probiotics used in Dr. M.S. Reddy’s Multiple Mixed Strain Probiotic Therapy to successfully treat C. diff infection.  A detailed scientific and research attempts were made to correlate the Probiotic induced immune activities in relation to the reduction of the symptoms associated with the hospital acquired Clostridium difficile infection during and after the Multiple Mixed Strain Probioitc Therapy.  Results of the clinical trials, microbiological tests on feces, and the clinical blood tests significantly revealed that the reasons for the success of Dr. Reddy’s Multiple Mixed Strain Probiotic Therapy are multifold. Presumably, it is predominantly due to the immunomodulatory effect they have exerted on the host immune system along with the direct inhibition of C. diff bacteria by multiple Probiotics, due to the production of bacteriocins, lactic acid and nutritional competency.In addition, the size of the individual cells of the Probiotic strains in the Multiple Mixed Strain Probiotics and their significant effect on immunomodulation has been thoroughly discussed. Results clearly proved that if Probiotics are absent in the GI tract during C. diff infection, the chances of patient survival is zero.  This is because of the excess immune stimulation and incurable damage to the epithelial cell barrier of the gastrointestinal tract caused by C. diff bacteria.  The results also revealed, without any doubt, as of to-datethe latest discovery of Dr. M.S. Reddy’s Multiple Mixed Strain Probiotic Therapy is the best way to cure the deadly hospital acquired infections affecting millions of people around the world, with high degree of mortality.  This has been attested by several practicng medical professionals and scientists around the world (Reddy and Reddy, 2017).


Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1066
Author(s):  
Fahima Abdellatif ◽  
Muhammad Akram ◽  
Samir Begaa ◽  
Mohammed Messaoudi ◽  
Adel Benarfa ◽  
...  

This study describes the minerals elements, chemical composition, antioxidant and antimicrobial activities of Algerian Melissa officinalis plant. The essential oil (EO) was extracted by hydrodistillation (HD) using a Clevenger-type apparatus of dry leaves of M. officinalis and was analyzed by two techniques, gas chromatography coupled with flame ionization (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS). Eighteen minerals comprising both macro- and microelements (As, Br, K, La, Na, Sb, Sm, Ba, Ca, Ce, Co, Cr, Cs, Fe, Rb, Sc, Th, and Zn) were determined using neutron activation analysis technique for the first time from Algerian Melissa officinalis plant. Seventy-eight compounds were identified in the essential oil, representing 94.090% of the total oil and the yields were 0.470%. The major component was geranial (45.060%). Other predominant components were neral (31.720%) and citronellal (6.420%). The essential oil presented high antimicrobial activity against microorganisms, mainly five human pathogenic bacteria, one yeast, Candida albicans, and two phytopathogenic fungi. The results can be used as a source of information for the pharmaceutical industry and medical research.


2021 ◽  
Vol 12 (1) ◽  
pp. 85-93
Author(s):  
Wallapat Phongtang ◽  
Ekachai Chukeatirote

Abstract Bacillus cereus is considered to be an important food poisoning agent causing diarrhea and vomiting. In this study, the occurrence of B. cereus bacteriophages in Thai fermented soybean products (Thua Nao) was studied using five B. cereus sensu lato indicator strains (four B. cereus strains and one B. thuringiensis strain). In a total of 26 Thua Nao samples, there were only two bacteriophages namely BaceFT01 and BaceCM02 exhibiting lytic activity against B. cereus. Morphological analysis revealed that these two bacteriophages belonged to the Myoviridae. Both phages were specific to B. cereus and not able to lyse other tested bacteria including B. licheniformis and B. subtilis. The two phages were able to survive in a pH range between 5 and 12. However, both phages were inactive either by treatment of 50°C for 2 h or exposure of UV for 2 h. It should be noted that both phages were chloroform-insensitive, however. This is the first report describing the presence of bacteriophages in Thua Nao products. The characterization of these two phages is expected to be useful in the food industry for an alternative strategy including the potential use of the phages as a biocontrol candidate against foodborne pathogenic bacteria.


Planta Medica ◽  
2021 ◽  
Author(s):  
Vincent Brieudes ◽  
Eleni V. Mikropoulou ◽  
Errikos Kallergis ◽  
Andriana C. Kaliora ◽  
Efstathia Papada ◽  
...  

AbstractChios mastic gum is the resinous secretion obtained from the barks of the shrub Pistacia lentiscus var. Chia, which is endemic to the Greek island of Chios. Since antiquity, Chios mastic gum has found several uses as a phytotherapeutic remedy, primarily for the treatment of gastrointestinal disorders while recently, Chios mastic gum was also recognized by EMA as an herbal medicinal product with specific indications. Chios mastic gumʼs biological properties are attributed to triterpenes which comprise the major chemical group (approx. 70%) and notably isomasticadienonic acid and masticadienonic acid. However, due to their structural characteristics, the isolation thereof in high yield and purity is challenging and since they are not commercially available, pharmacological studies aiming to assess their biological properties are limited. In the present work, masticʼs phytochemical investigation by UPLC-HRMS is followed by the isolation and characterization of isomasticadienonic acid and masticadienonic acid to be used as analytical standards for their accurate and reliable quantification in human plasma. A UHPLC-tQ-MS method that was developed and validated (in terms of specificity, linearity, limit of quantification, accuracy and precision), for the direct quantification of the targeted compounds in the low ng/mL range of concentration, was subsequently implemented on plasma samples of healthy volunteers thus demonstrating its fitness for purpose. The results presented herein might provide insight to the understanding of this traditional natural product consumed notably for its anti-inflammatory, antioxidant and lipid lowering properties. Moreover, this method might serve as a starting point for any study aiming to monitor bioactive triterpenes in biological fluids.


Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 979 ◽  
Author(s):  
Fei Wang ◽  
Jin Zhang ◽  
Bo Zhu ◽  
Jie Wang ◽  
Qiao Wang ◽  
...  

Salmonella is one of the most common food-borne pathogens. It can be transmitted between chickens, as well as to people by contaminated poultry products. In our study, we distinguished chickens with different resistances mainly based on bacterial loads. We compared the cecal tonsil transcriptomes between the susceptible and resistant chickens after Salmonella infection, aiming to identify the crucial genes participating in the antibacterial activity in the cecal tonsil. A total of 3214 differentially expressed genes (DEGs), including 2092 upregulated and 1122 downregulated genes, were identified between the two groups (fold change ≥ 2.0, padj < 0.05). Many DEGs were mainly involved in the regulation of two biological processes: crosstalk between the cecal tonsil epithelium and pathogenic bacteria, such as focal adhesion, extracellular-matrix–receptor interaction, and regulation of the actin cytoskeleton and host immune response including the cytokine–receptor interaction. In particular, the challenged resistant birds exhibited strong activation of the intestinal immune network for IgA production, which perhaps contributed to the resistance to Salmonella infection. These findings give insight into the mRNA profile of the cecal tonsil between the two groups after initial Salmonella stimulation, which may extend the known complexity of molecular mechanisms in chicken immune response to Salmonella.


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