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Topic Review
Antimicrobial Resistance in Acinetobacter baumannii
Acinetobacter baumannii is a Gram-negative bacillus that causes multiple infections that can become severe, mainly in hospitalized patients. Its high ability to persist on abiotic surfaces and to resist stressors, together with its high genomic plasticity, make it a remarkable pathogen. The isolation of strains with high antimicrobial resistance profiles has gained relevance, which complicates patient treatment and prognosis. This resistance capacity is generated by various mechanisms, including the modification of the target site where antimicrobial action is directed. This mechanism is mainly generated by genetic mutations and contributes to resistance against a wide variety of antimicrobials, such as β-lactams, macrolides, fluoroquinolones, aminoglycosides, among others, including polymyxin resistance, which includes colistin, a rescue antimicrobial used in the treatment of multidrug-resistant strains of A. baumannii and other Gram-negative bacteria.
  • 907
  • 27 Jun 2022
Topic Review
Viable but Non-Culturable Listeria monocytogenes
The detection, enumeration, and virulence potential of viable but non-culturable (VBNC) pathogens continues to be a topic of discussion. While there is a lack of definitive evidence that VBNC Listeria monocytogenes (Lm) pose a public health risk, recent studies suggest that Lm in its VBNC state remains virulent. VBNC bacteria cannot be enumerated by traditional plating methods, so the results from routine Lm testing may not demonstrate a sample’s true hazard to public health. We suggest that supplementing routine Lm testing methods with methods designed to enumerate VBNC cells may more accurately represent the true level of risk.
  • 904
  • 13 Feb 2021
Topic Review
Dietary Fibers and Intestinal Microbiota Affects T2D
Foods contain dietary fibers which can be classified into soluble and insoluble forms. The nutritional composition of fast foods is considered unhealthy because it negatively affects the production of short-chain fatty acids (SCFAs). Dietary fiber is resistant to digestive enzymes in the gut, which modulates the anaerobic intestinal microbiota (AIM) and fabricates SCFAs. Acetate, butyrate, and propionate are dominant in the gut and are generated via Wood–Ljungdahl and acrylate pathways. In pancreatic dysfunction, the release of insulin/glucagon is impaired, leading to hyperglycemia. SCFAs enhance insulin sensitivity or secretion, beta-cell function, leptin release, mitochondrial function, and intestinal gluconeogenesis in human organs, which positively affects type 2 diabetes (T2D). Research models have shown that SCFAs either enhance the release of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) from L-cells (entero-endocrine), or promotes the release of leptin hormone in adipose tissues through G-protein receptors GPR-41 and GPR-43. Dietary fiber is a component that influences the production of SCFAs by AIM, which may have beneficial effects on T2D.
  • 903
  • 22 May 2023
Topic Review
Avian Reovirus
Avian reoviruses belong to the genus Orthoreovirus, and Reoviridae family. They are non-enveloped viruses that undergo replication in the cytoplasm of infected cells. It has icosahedral symmetry and contains a double-shelled arrangement of surface protein. Virus particles can range between 70–80 nm. Morphologically, the virus is a double stranded RNA virus that is composed of ten segments. The genome and proteins that are encoded by the genome can be separated into three different sizes ranging from small, medium, or large. Of the eleven proteins that are encoded for by the genome, two are nonstructural, while the remaining nine are structural. Avian reoviruses can withstand a pH range of 3.0–9.0. Ambient temperatures are suitable for the survival of these viruses, which become inactive at 56 °C in less than an hour. Common areas where this virus can survive include galvanized metal, glass, rubber, feathers, and wood shavings. Avian reovirus can survive for up to ten days on these common areas in addition to up to ten weeks in water. Cultivation and observation of the effects of avian reovirus is most often performed in chicken embryos. If infected into the yolk sac, the embryo will succumb to death accompanied by hemorrhaging of the embryos and cause the foci on the liver to appear yellowish-green. There are several primary chicken cell cultures/areas that are susceptible to avian reoviruses, which include the lungs, liver, kidney, and fibroblasts of the chick embryo. Of the following susceptible areas, liver cells from the chick embryo have been found to be the most sensitive for primary isolation from clinical material. Typically, the CPE effect of avian reoviruses is the production of syncytia. CPE, or cytopathic effects are the visible changes in a host cell that takes place because of viral infection. Syncytia is a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei.
  • 902
  • 14 Nov 2022
Topic Review
Oxidative-Stress-Mediated Antimicrobial Properties of Metal-Based Nanoparticles
Nanotechnologies have provided opportunities for the use of nanomaterials as components in the development of antibacterial agents. Indeed, metal-based nanoparticles (NPs) show an effective role in targeting and killing bacteria via different mechanisms, such as attraction to the bacterial surface, destabilization of the bacterial cell wall and membrane, and the induction of a toxic mechanism mediated by a burst of oxidative stress. Considering the lack of new antimicrobial drugs with novel mechanisms of action, the induction of oxidative stress represents a valuable and powerful antimicrobial strategy to fight MDR bacteria. Consequently, it is of particular interest to determine and precisely characterize whether NPs are able to induce oxidative stress in such bacteria. 
  • 901
  • 28 Feb 2022
Topic Review
Bacteriophage Therapy to Control Bovine Mastitis
Bovine mastitis is a polymicrobial disease characterised by inflammation of the udders of dairy and beef cattle. The infection has huge implications to health and welfare of animals, impacting milk and beef production and costing up to EUR 32 billion annually to the dairy industry, globally. Bacterial communities associated with the disease include representative species from Staphylococcus, Streptococcus, Enterococcus, Actinomyces, Aerococcus, Escherichia, Klebsiella and Proteus. Conventional treatment relies on antibiotics, but antimicrobial resistance, declining antibiotic innovations and biofilm production negatively impact therapeutic efficacy. Bacteriophages (phages) are viruses which effectively target and lyse bacteria with extreme specificity and can be a valuable supplement or replacement to antibiotics for bovine mastitis. 
  • 901
  • 29 Aug 2023
Topic Review
Immune Response to Necrotic Enteritis in Broilers
Clostridium perfringens type A and C are the primary etiological agents associated with necrotic enteritis (NE) in poultry. The predisposing factors implicated in the incidence of NE changes the physical properties of the gut, immunological status of birds, and disrupt the gut microbial homeostasis, causing an over-proliferation of C. perfringens. The principal virulence factors contributing to the pathogenesis of NE are the α-toxin, β-toxin, and NetB toxin. The immune response to NE in poultry is mediated by the Th1 pathway or cytotoxic T-lymphocytes. C. perfringens type A and C are also pathogenic in humans, and hence are of public health significance. C. perfringens intoxications are the third most common bacterial foodborne disease after Salmonella and Campylobacter.
  • 900
  • 28 Oct 2022
Topic Review
Lung Microbiome
The lung microbiome has recently emerged as a major mediator of host inflammation and pathogenesis. Understanding how the lung microbiota exerts its effects on lung cancer and the tumor microenvironment will allow for novel development of therapies.
  • 899
  • 04 Jan 2021
Topic Review
Mycobacteria and Cancer
Although the therapeutic effect of mycobacteria as antitumor agents has been known for decades, recent epidemiological and experimental studies have revealed that mycobacterium-related chronic inflammation may be a possible mechanism of cancer pathogenesis. Mycobacterium tuberculosis and non-tuberculous Mycobacterium avium complex infections have been implicated as potentially contributing to the etiology of lung cancer, whereas Mycobacterium ulcerans has been correlated with skin carcinogenesis. The risk of tumor development with chronic mycobacterial infections is thought to be a result of many host effector mechanisms acting at different stages of oncogenesis.
  • 899
  • 28 Sep 2021
Topic Review
Water Age and Plumbing Pathogens
One of the most important characteristics that can affect the growth and proliferation of opportunistic pathogens in premise plumbing systems is water age. Water age is a term that represents the average time taken for water to reach its point-of-use from its point-of-entry within a distribution system. It is more precisely defined as a summation of residence time from the treatment facility to the water meter of a building (i.e., mains distribution) and residence time from the water meter to the point of use (i.e., premise plumbing distribution). Water age can be described primarily as a function of water demand, system design, and system operation. As demand increases, the time that water is resident in a system decreases.
  • 898
  • 08 Jun 2021
Topic Review
Meningococcal Vaccines and Mucosal Immunity
Neisseria meningitidis causes a devastating invasive disease but is also a normal colonizer of the human nasopharynx. Due to the rapid progression of disease, the best tool to protect individuals against meningococcal infections is immunization. Clinical experience with polysaccharide conjugate vaccines has revealed that an ideal meningococcal vaccine must prevent both invasive disease and nasal colonization, which confers herd immunity. However, not all meningococcal vaccines are equal in their ability to prevent nasal colonization, for unknown reasons. 
  • 898
  • 23 Jul 2021
Topic Review
Coliphages in Urban Wastewater Treatments
There is an urgent need to control the fate of fecal microorganisms in wastewater to avoid the negative health consequences of releasing treated effluents into surface waters (rivers, lakes, etc.) or marine coastal water. On the other hand, the measurement of bacterial indicators yields insufficient information to gauge the human health risk associated with viral infections. It would therefore seem advisable to include a viral indicator—for example, somatic coliphages—to monitor the functioning of wastewater treatments.
  • 897
  • 08 Jul 2021
Topic Review
Microbe-Assisted Remediation of Crude-Oil-Contaminated Environment
Crude oil contamination is an emerging environmental concern on a global scale due to inadvertent oil leakage. Oil spillage and discharges frequently happen as a consequence of explosion incidents during oilfield drilling; leakage from oil and gas pipelines and reservoirs, fuel tankers, and well waxing; and during overhauls of refineries and petrochemical manufacturing equipment. Crude oil and its products damage water and air quality and also reduce soil fertility. Crude oil can harm plants by clogging soil pores, reducing soil aeration and water permeability, which can have both ecological and toxicological effects and disrupt the soil’s natural structure. Aside from these environmental concerns, one of the most serious consequences of such anthropogenic emissions is current global climate change. Crude oil contamination not only impacts different ecosystems but also influences global socio-economic status.
  • 897
  • 25 Apr 2023
Topic Review
Phage-Based Biosensors
Bacteriophage-based biosensors offer several benefits, including specificity to their host organism, the detection of only live pathogens, and resistance to extreme environmental factors such as organic solvents, high temperatures, and a wide pH range. Phage-based biosensors are receiving increasing attention owing to their high degree of accuracy, specificity, and reduced assay times. These characteristics, coupled with their abundant supply, make phages a novel bio-recognition molecule in assay development, including biosensors for the detection of foodborne bacterial pathogens to ensure food safety.
  • 896
  • 26 Oct 2022
Topic Review
Liquid Fermentation of Edible and Medicinal Fungi
Liquid fermentation of edible and medicinal fungi involves cultivating and growing fungi in a liquid medium, providing optimal conditions for their growth and fermentation. This method offers advantages over traditional solid-state fermentation, such as better control of environmental factors, higher yield and purity, and faster production cycles. It also enables the extraction of bioactive compounds with therapeutic potential, which can be utilized in pharmaceuticals, nutraceuticals, cosmetics, and functional foods. Overall, it is a modern technique for producing high-quality fungal products with enhanced bioactive properties.
  • 896
  • 21 Sep 2023
Topic Review
Robert Koch
Robert Heinrich Hermann Koch was a pioneering German physician and microbiologist whose groundbreaking work laid the foundations for modern bacteriology. He is most renowned for discovering the causative agents of tuberculosis, cholera, and anthrax, and for formulating the postulates that define pathogenic organisms in infectious diseases.
  • 896
  • 14 Jul 2025
Topic Review
Inoviridae
Inoviridae is a family of viruses that infect bacteria. Members of the family are commonly called filamentous bacteriophages due to their filamentous shape that resembles a worm-like chain (long, thin and flexible, reminiscent of a length of cooked spaghetti) about 6 nm in diameter and about 1000-2000 nm long. Filamentous bacteriophages are among the simplest living organisms known, with far fewer genes than the classical bacteriophages studied by the phage group. Its simplicity makes it an attractive model system to study fundamental aspects of molecular biology, and it has also proven useful as a tool in immunology and nanotechnology. The family contains 29 defined species, divided between 23 genera. However, mining of genomic and metagenomic datasets using machine learning approach led to the discovery of 10,295 inovirus-like sequences in nearly all bacterial phyla across virtually every ecosystem, indicating that this group of viruses is much more diverse and widespread than originally appreciated.
  • 895
  • 20 Nov 2022
Topic Review
Metallo-β-Lactamase Fold Enzymes in Bacteria
β-lactamase enzymes have generated significant interest due to their ability to confer resistance to the most commonly used family of antibiotics in human medicine. Among these enzymes, the class B β-lactamases are members of a superfamily of metallo-β-lactamase (MβL) fold proteins which are characterised by conserved motifs (i.e., HxHxDH) and are not only limited to bacteria.
  • 895
  • 13 Jul 2023
Topic Review
Helminthophagous Fungi
Helminthophagous fungi can be divided into five groups: nematode-trapping/predatorial, opportunistic or ovicidal, endoparasitic, toxin-producing, and producers of special attack devices. The fungi of the first and second groups produce modified hyphae called traps, with which, by a mechanical/enzymatic process, they bind and digest nematode larvae, eggs, cysts, and nematode females. Thus, they are the ones that best act in the predation of animal parasites. Supplied orally, after passing through the gastrointestinal tract of animals, fungal structures such as conidia, mycelium, and chlamidospores germinate in the feces, forming a network of hyphae with the ability to capture and destroy infective forms of animal parasitic helminths.
  • 893
  • 30 Nov 2021
Topic Review
Legionella pneumophila in Dental Practice
Legionella pneumophila is defined as a bacterium that can cause severe pneumonia. It is found in the natural environment and in water, and is often found in water tanks. It can be an integral part of biofilms in nature, and the protozoa in which it can live provide it with food and protect it from harmful influences; therefore, it has the ability to move into a sustainable but uncultured state (VBNC). L. pneumophila has been shown to cause infections in dental practices. The most common transmission route is aerosol generated in dental office water systems, which can negatively affect patients and healthcare professionals. The most common way of becoming infected with L. pneumophila in a dental office is through water from dental instruments, and the dental unit. In addition to these bacteria, patients and the dental team may be exposed to other harmful bacteria and viruses. Therefore, it is vital that the dental team regularly maintains and decontaminates the dental unit, and sterilizes all accessories that come with it. In addition, regular water control in dental offices is necessary. 
  • 892
  • 14 Mar 2022
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