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Topic Review
Heavy Metals Bioremediation
Cadmium (Cd), chromium (Cr) and lead (Pb) are heavy metals that have been classified as priority pollutants in aqueous environment while methane-oxidizing bacteria as a biofilter arguably consume up to 90% of the produced methane in the same aqueous environment before it escapes into the atmosphere. However, the underlying kinetics and active methane oxidizers are poorly understood for the hotspot of epipelon that provides a unique micro-ecosystem containing diversified guild of microorganisms including methane oxidizers for potential bioremediation of heavy metals. In the present study, the Pb2+, Cd2+and Cr6+ bioremediation potential of epipelon biofilm was assessed under both high (120,000 ppm) and near-atmospheric (6 ppm) methane concentrations. Epipelon biofilm demonstrated a high methane oxidation activity following microcosm incubation amended with a high concentration of methane, accompanied by the complete removal of 50 mg L−1 Pb2+ and 50 mg L−1 Cd2+ (14 days) and partial (20%) removal of 50 mg L−1 Cr6+ after 20 days. High methane dose stimulated a faster (144 h earlier) heavy metal removal rate compared to near-atmospheric methane concentrations. DNA-based stable isotope probing (DNA-SIP) following 13CH4 microcosm incubation revealed the growth and activity of different phylotypes of methanotrophs during the methane oxidation and heavy metal removal process. High throughput sequencing of 13C-labelled particulate methane monooxygenase gene pmoA and 16S rRNA genes revealed that the prevalent active methane oxidizers were type I affiliated methanotrophs, i.e., Methylobacter. Type II methanotrophs including Methylosinus and Methylocystis were also labeled only under high methane concentrations. These results suggest that epipelon biofilm can serve as an important micro-environment to alleviate both methane emission and the heavy metal contamination in aqueous ecosystems with constant high methane fluxes.
  • 1.1K
  • 27 Oct 2020
Topic Review
HTLV-1 and Strongyloides stercoralis
Infection with HTLV-1 has been associated with various clinical syndromes including co-infection with Strongyloides stercoralis, which is an intestinal parasitic nematode and the leading cause of strongyloidiasis in humans. Interestingly, HTLV-1 endemic areas coincide with regions citing high prevalence of S. stercoralis infection, making these communities optimal for elucidating the pathogenesis of co-infection and its clinical significance. HTLV-1 co-infection with S. stercoralis has been observed for decades in a number of published patient cases and case series; however, the implications of this co-infection remain elusive. Thus far, data suggest that S. stercoralis increases proviral load in patients co-infected with HTLV-1 compared to HTLV-1 infection alone. Furthermore, co-infection with HTLV-1 has been associated with shifting the immune response from Th2 to Th1, affecting the ability of the immune system to address the helminth infection. Thus, further research is required to fully elucidate the impact of each pathogen in co-infected patients. This review provides an analytical view of studies that have evaluated the variation within HTLV-1 patients in susceptibility to S. stercoralis infection, as well as the effects of strongyloidiasis on HTLV-1 pathogenesis. Further, it provides a compilation of  available clinical reports on the epidemiology and pathology of HTLV-1 with S. stercoralis co-infection, as well as data from mechanistic studies, to facilitate moving this field forward.
  • 1.1K
  • 23 Nov 2020
Topic Review
New Carbapenemase Inhibitors
Carbapenem resistance is a major global health problem that seriously compromises the treatment of infections caused by nosocomial pathogens. Production of carbapenemases (carbapenem-hydrolyzing enzymes) is the most important mechanism of carbapenem resistance. A new generation of promising carbapenemase inhibitors, together with the recently approved avibactam, relebactam and vaborbactam are being tested in clinical and pre-clinical trials.This review summarizes the main, most promising carbapenemase inhibitors synthesized to date. 
  • 1.1K
  • 30 Dec 2020
Topic Review
Spirochetes as Causative Agents of Alzheimer’s Disease
Spirochetes are bacteria that can also form biofilms, and there is increasing evidence regarding infections with specific species. Borrelia burgdorferi, and several species of treponemes are some of the most studied spirochetes regarding Alzheimer’s Disease. Spirochetes were visualized in the neurofibrillary tangles and senile plaques in the brains of individuals with AD, and peptidoglycan was also located near Aβ deposits.
  • 1.1K
  • 06 Jan 2022
Topic Review
Targeting Gut Microbial Biofilms
Colorectal cancer (CRC) is a global public health issue which poses a substantial humanistic and economic burden on patients, healthcare systems and society. In recent years, intestinal dysbiosis has been suggested to be involved in the pathogenesis of CRC, with specific pathogens exhibiting oncogenic potentials such as Fusobacterium nucleatum, Escherichia coli and enterotoxigenic Bacteroides fragilis having been found to contribute to CRC development. More recently, it has been shown that initiation of CRC development by these microorganisms requires the formation of biofilms. Gut microbial biofilm forms in the inner colonic mucus layer and is composed of polymicrobial communities. Biofilm results in the redistribution of colonic epithelial cell E-cadherin, increases permeability of the gut and causes a loss of function of the intestinal barrier, all of which enhance intestinal dysbiosis. This literature review aims to compile the various strategies that target these pathogenic biofilms and could potentially play a role in the prevention of CRC. We explore the potential use of natural products, silver nanoparticles, upconverting nanoparticles, thiosalicylate complexes, anti-rheumatic agent (Auranofin), probiotics and quorum-sensing inhibitors as strategies to hinder colon carcinogenesis via targeting colon-associated biofilms.
  • 1.1K
  • 22 Oct 2020
Topic Review
Hepatitis B Virus Infection Understanding
Chronic hepatitis B virus (HBV) infection affects 292 million people worldwide and is associated with a broad range of clinical manifestations including cirrhosis, liver failure, and hepatocellular carcinoma (HCC). Despite the availability of an effective vaccine HBV still causes nearly 900,000 deaths every year. Current treatment options keep HBV under control, but they do not offer a cure as they cannot completely clear HBV from infected hepatocytes. The recent development of reliable cell culture systems allowed for a better understanding of the host and viral mechanisms affecting HBV replication and persistence. Recent advances into the understanding of HBV biology, new potential diagnostic markers of hepatitis B infection, as well as novel antivirals targeting different steps in the HBV replication cycle are summarized in this review article.
  • 1.1K
  • 29 Sep 2020
Topic Review
Probiotics in cosmetics
Probiotics, defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host,” are becoming increasingly popular and marketable. The cosmetic industry has harnessed this potential by producing products claiming to contain probiotics. However, not all products marketed as such comply with the requirements for this claim.  
  • 1.1K
  • 10 Mar 2021
Topic Review
Antimicrobial Potential of Curcumin
Curcumin is a bioactive compound that is extracted from Curcuma longa and that is known for its antimicrobial properties. Curcuminoids are the main constituents of curcumin that exhibit antioxidant properties. It has a broad spectrum of antibacterial actions against a wide range of bacteria, even those resistant to antibiotics. Curcumin has been shown to be effective against the microorganisms that are responsible for surgical infections and implant-related bone infections, primarily Staphylococcus aureus and Escherichia coli. The efficacy of curcumin against Helicobacter pylori and Mycobacterium tuberculosis, alone or in combination with other classic antibiotics, is one of its most promising antibacterial effects. Curcumin is known to have antifungal action against numerous fungi that are responsible for a variety of infections, including dermatophytosis. Candidemia and candidiasis caused by Candida species have also been reported to be treated using curcumin. Life-threatening diseases and infections caused by viruses can be counteracted by curcumin, recognizing its antiviral potential.
  • 1.1K
  • 16 Mar 2022
Topic Review
Salmonella enterica
Salmonella enterica serovars are important pathogens of humans and animals that are responsible for enormous morbidity, mortality and economic loss worldwide.  Models used to study the disease pathology so far have provided valuable advancements, however, the molecular complexity of its pathogenesis remains poorly understood, particularly in humans. Therefore there remains a disconnect between what works at the bench versus at the bedside, especially in case of vaccines. The development of organoids/enteroids offers a tremendous opportunity to bridge this gap by bringing human-specific factors into the research models as well as elevate our understanding of the interactions and crosstalk between multiple cell types and the microbiota with Salmonella. Thus the use of organoids in studying Salmonella biology has the potential for improving clinical outcomes and future prophylactic and therapeutic intervention strategies.
  • 1.1K
  • 29 Oct 2020
Topic Review
Wood Antimicrobial Behavior Test Method
Some wood species have antimicrobial properties and a variety of methods are used to investigate them. For testing the effect of antimicrobial compounds, direct and indirect methods are used. Meanwhile, the survival of microbes is also tested on surfaces (or material in contact with microbes) to validate the safety of surfaces.
  • 1.1K
  • 29 Oct 2020
Topic Review
Dysregulation of Microbiome–Immunity Interaction in Various Diseases
Gut microbes and their metabolites are actively involved in the development and regulation of host immunity, which can influence disease susceptibility. The role of the microbiome as a protective force is supported by research indicating that immature microbiomes of neonates are more susceptible to invasion by pathobionts. During early years of development, exposure to various microbes shapes the immune system for a lifetime. The gut microbiome has a wide range of metabolic activities, including metabolizing lipids, carbohydrates, and proteins, and participates in maintaining host homeostasis. Therefore, disruption of gut microbiome can lead to conditions as severe as cancer.
  • 1.1K
  • 06 Feb 2023
Topic Review
Clostridium Difficile Infection
Clostridium difficile infection (CDI or C-dif) is a symptomatic infection due to the spore-forming bacterium, Clostridium difficile. Symptoms include watery diarrhea, fever, nausea, and abdominal pain. It makes up about 20% of cases of antibiotic-associated diarrhea. Complications may include pseudomembranous colitis, toxic megacolon, perforation of the colon, and sepsis. Clostridium difficile infection is spread by bacterial spores found within feces. Surfaces may become contaminated with the spores with further spread occurring via the hands of healthcare workers. Risk factors for infection include antibiotic or proton pump inhibitors use, hospitalization, other health problems, and older age. Diagnosis is by stool culture or testing for the bacteria's DNA or toxins. If a person tests positive but has no symptoms, the condition is known as C. difficile colonization rather than an infection. Prevention is by hand washing, terminal room cleaning in hospital, and limiting antibiotic use. Discontinuation of antibiotics may result in resolution of symptoms within three days in about 20% of those infected. Often the antibiotics metronidazole, vancomycin or fidaxomicin will cure the infection. Retesting after treatment, as long as the symptoms have resolved, is not recommended, as the person may remain colonized. Recurrences have been reported in up to 25% of people. Some tentative evidence indicates fecal microbiota transplantation and probiotics may decrease the risk of recurrence. C. difficile infections occur in all areas of the world. About 453,000 cases occurred in the United States in 2011, resulting in 29,000 deaths. Rates of disease globally have increased between 2001 and 2016. Women are more often affected than men. The bacterium was discovered in 1935 and found to be disease-causing in 1978. In the United States, health–care associated infections increase the cost of care by US$1.5 billion each year.
  • 1.1K
  • 07 Nov 2022
Topic Review
Limosilactobacillus fermentum CECT5716
Limosilactobacillus fermentum CECT5716 has become one of the most promising probiotics and it has been described to possess potential beneficial effects on inflammatory processes and immunological alterations.
  • 1.1K
  • 15 Apr 2021
Topic Review
Multidrug Resistant Gram-Negative Bacteria
Antibiotic resistance has increased markedly in Gram-negative bacteria, causing severe infections intractable with traditional drugs and amplifying mortality and healthcare costs. Consequently, to find novel antimicrobial compounds, active on multidrug resistant bacteria, is mandatory. In this regard, cationic antimicrobial peptides (CAMPs)—able to kill pathogens on contact—could represent an appealing solution. However, low selectivity, hemolytic toxicity and cost of manufacturing, hamper their massive clinical application. In the recent years—starting from CAMPs as template molecules—less toxic and lower-cost synthetic mimics of CAMPs, including cationic peptides, polymers and dendrimers, have been developed. Although the pending issue of hemolytic toxicity and biodegradability is still left not completely solved, cationic antimicrobial polymers (CAPs), compared to small drug molecules, thanks to their high molecular weight, own appreciable selectivity, reduced toxicity toward eukaryotic cells, more long-term activity, stability and non-volatility. With this background, an updated overview concerning the state of the art of the main manufactured types of CAPs, active on Gram-negative bacteria, is herein reported, including synthetic procedure and action’s mechanism. Information about the antibacterial activity, advantages and drawbacks of the most appealing compounds was also provided.
  • 1.1K
  • 28 Oct 2020
Topic Review
Bacteremia
Bacteremia (also bacteraemia) is the presence of bacteria in the blood. Blood is normally a sterile environment, so the detection of bacteria in the blood (most commonly accomplished by blood cultures) is always abnormal. It is distinct from sepsis, which is the host response to the bacteria. Bacteria can enter the bloodstream as a severe complication of infections (like pneumonia or meningitis), during surgery (especially when involving mucous membranes such as the gastrointestinal tract), or due to catheters and other foreign bodies entering the arteries or veins (including during intravenous drug abuse). Transient bacteremia can result after dental procedures or brushing of teeth. Bacteremia can have several important health consequences. The immune response to the bacteria can cause sepsis and septic shock, which has a high mortality rate. Bacteria can also spread via the blood to other parts of the body (which is called hematogenous spread), causing infections away from the original site of infection, such as endocarditis or osteomyelitis. Treatment for bacteremia is with antibiotics, and prevention with antibiotic prophylaxis can be given in high risk situations.
  • 1.1K
  • 10 Oct 2022
Topic Review
Cytophagales
Cytophagales is an order of non-spore forming, rod-shaped, Gram-negative bacteria that move through a gliding or flexing motion. These chemoorganotrophs are important remineralizers of organic materials into micronutrients. They are widely dispersed in the environment, found in ecosystems including soil, freshwater, seawater and sea ice. Cytophagales is included in the Bacteroidetes phylum.
  • 1.1K
  • 31 Oct 2022
Topic Review
Endolysins
Endolysins are phage-encoded enzymes utilized by mature phage virions to hydrolyze the cell wall from within. There is significant evidence that proves the ability of endolysins to degrade the peptidoglycan externally without the assistance of phage. Thus, their incorporation in therapeutic strategies has opened new options for therapeutic application against bacterial infections in the human and veterinary sectors, as well as within the agricultural and biotechnology sectors. While endolysins show promising results within the laboratory, it is important to document their resistance, safety, and immunogenicity for in-vivo application.
  • 1.1K
  • 24 Mar 2021
Topic Review
Mycobacteriophages for Drug-Resistant Tuberculosis Treatment
The current emergence of multi-, extensively-, extremely-, and total-drug resistant strains of Mycobacterium tuberculosis poses a major health, social, and economic threat, and stresses the need to develop new therapeutic strategies. Mycobacteriophages are genetically diverse viruses that specifically infect mycobacterial hosts, including members of the M. tuberculosis complex. Here, we will review general features of mycobacteriophages and their mechanisms of M.tb killing, as well as their advantages and limitations as therapeutic and prophylactic agents against drug-resistant M.tb. 
  • 1.1K
  • 31 Mar 2021
Topic Review
Anaerobic Phototrophic Sulfur Bacteria
Phototrophic purple and green sulfur bacteria have been known for a long time. These microorganisms are characterized by using reduced sulfur (S) compounds as electron donors in the process of anoxygenic photosynthesis and are classified into different families based on their morphology, physiological and biochemical characteristics. Representatives of the largest family, the Chromatiaceae—members of which may be observed in nature as a light red coloration of the anaerobic layer of water—were first described in the second half of the 19th century. In contrast, the less numerous Chlorobiaceae family—also referred to as green sulfur bacteria—were isolated later in the second half of the 20th century.
  • 1.1K
  • 24 Jun 2021
Topic Review
Zetaproteobacteria
The class Zetaproteobacteria is the sixth and most recently described class of the Proteobacteria. Zetaproteobacteria can also refer to the group of organisms assigned to this class. The Zetaproteobacteria were originally represented by a single described species, Mariprofundus ferrooxydans, which is an iron-oxidizing neutrophilic chemolithoautotroph originally isolated from Loihi Seamount in 1996 (post-eruption). Molecular cloning techniques focusing on the small subunit ribosomal RNA gene have also been used to identify a more diverse majority of the Zetaproteobacteria that have as yet been unculturable. Regardless of culturing status, the Zetaproteobacteria show up worldwide in estuarine and marine habitats associated with opposing steep redox gradients of reduced (ferrous) iron and oxygen, either as a minor detectable component or as the dominant member of the microbial community. Zetaproteobacteria have been most commonly found at deep-sea hydrothermal vents, though recent discovery of members of this class in near-shore environments has led to the reevaluation of Zetaproteobacteria distribution and significance.
  • 1.1K
  • 18 Nov 2022
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