Critical Reviews in Microbiology

The growing demand for nanomedicine and its potentially diverse biological function required the investigation of raw materials for fabricating the nanomaterial. Current developments have emphasized the implementation of green chemistry to develop metal-oxide and metal nanoparticles. Endophytic fungi have emerged as a potential reservoir of bioactive compounds exemplified by unique structures and influential antibacterial properties. Over the past decade, substantial progress has been achieved in uncovering and profiling these valuable antibacterial compounds. These endophytic fungi-derived bioactive chemicals have diverse applications in various biological properties. Nanoparticle synthesis from materials derived from endophytic fungi, be it whole extracts or pure components, owing to their accessibility, cost-effectiveness in fabrication, material-tissue compatibility, and modest cytotoxicity toward higher organism cells. Nanoparticles from endophytic fungi have been utilized to treat various diseases, including those caused by bacterial, viral, and fungal pathogens. The present review provides a comprehensive discussion of the mechanistic insight into the synthesis and application of endophytic fungi-bioinspired nanoparticles as potential therapeutic agents to control microbial infection. The underlying action mechanism involved in the antimicrobial action of the nanoparticles has also been discussed. The discussion highlights various attributes of nanoparticles that may significantly benefit future researchers as potential therapeutic agents to control microbial infection.

Antimicrobial resistance threatens humans and animals worldwide and is recognized as one of the leading global public health issues. Escherichia coli (E. coli) has an unquestionable role in carrying and transmitting antibiotic resistance genes (ARGs), which in many cases are encoded on plasmids or phage, thus creating the potential for horizontal gene transfer. In this literature review, the authors summarize the major antibiotic resistance genes occurring in E. coli bacteria, through the major antibiotic classes. The aim was not only listing the resistance genes against the clinically relevant antibiotics, used in the treatment of E. coli infections, but also to cover the entire resistance gene carriage in E. coli, providing a more complete picture. We started with the long-standing antibiotic groups (beta-lactams, aminoglycosides, tetracyclines, sulfonamides and diaminopyrimidines), then moved toward the newer groups (phenicols, peptides, fluoroquinolones, nitrofurans and nitroimidazoles), and in every group we summarized the resistance genes grouped by the mechanism of their action (enzymatic inactivation, antibiotic efflux, reduced permeability, etc.). We observed that the frequency of antibiotic resistance mechanisms changes in the different groups.

Bacteria-mediated tumor treatment (BMTT) has recently garnered significant attention as a promising avenue in tumor treatment. Despite the application of various strains in animal models and clinical trials, the effectiveness of BMTT has been hindered by its toxicity and inefficiency. In recent years, it has been explored that applying the biological effects of ultrasound could further improve the precision and effectiveness of BMTT. This review briefly introduces the challenges of BMTT and summarizes how the biological effects of ultrasound improve the efficacy and safety of BMTT in strategies involving genetic engineering, visualization and targeted delivery. The potential application and limitations of ultrasound in advancing BMTT controllable strategies are also discussed.

Staphylococcus aureus (S. aureus) is a clinically significant opportunistic pathogen, and its colonization of the nasal cavity increases the risk of S. aureus infections in humans. Elucidating the mechanisms of nasal colonization by S. aureus would be beneficial in preventing infections, although this is intricate. The colonization of the nasal cavity by S. aureus depends firstly on the organism's ability to adhere to the nasal cavity, with surface components such as ClfB, IsdA, and wall teichoic acid playing an important role. Secondly, S. aureus must continuously adapt to the unfavorable environment in the nasal cavity, including epithelial cell shedding, weak acids, low nutrients, and mechanical forces, which is a prerequisite for maintaining reproduction. Furthermore, S. aureus evades the host immune system's clearance mechanisms by resisting antimicrobial substances and interfering with immune cells. Concurrently, there are interfering, competitive, or mutually beneficial relationships between the nasal microbiota and S. aureus that influence colonization.

Antimicrobial resistance (AMR) poses a significant public health threat, with emerging and novel forms of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) potentially crossing international borders and challenging the global health systems. The rate of development of antibiotic resistance surpasses the development of new antibiotics. Consequently, there is a growing threat of bacteria acquiring resistance even to newer antibiotics further complicating the treatment of bacterial infections. Horizontal gene transfer (HGT) is the key mechanism for the spread of antibiotic resistance in bacteria through the processes of conjugation, transformation, and transduction. Several compounds, other than antibiotics, have also been shown to promote HGT of ARGs. Given the crucial role of HGT in the dissemination of ARGs, inhibition of HGT is a key strategy to mitigate AMR. Therefore, this review explores the contribution of HGT in bacterial evolution, identifies specific hotspots andhighlights the role of HGT inhibitors in impeding the spread of ARGs. By specifically focusing on the HGT mechanism and its inhibition, these inhibitors offer a highly promising approach to combating AMR.

The complex interaction between Aspergillus and Bacillus has been gaining attention with the evolution of their co-culture applications. Information reported on this interaction from different points of view including both synergistic and antagonistic mechanisms necessitates a review for better understanding. This review focuses on the interaction, biofilm formation, and the diverse biotechnological applications of Aspergillus and Bacillus, giving special attention to Aspergillus niger and Bacillus subtilis. The review demonstrates that co-cultivation of Aspergillus and Bacillus exhibits significant transcriptional changes, impacting metabolism and secondary metabolite production in both organisms. Signaling from living fungal hyphae, EPS production, TasA fibrils, and regulators like Spo0A are essential in forming biofilm communities. Nutrient availability and pH levels, species type, and mutations in EPS-producing genes may also influence whether Bacillus will act antagonistically or synergistically with Aspergillus. This dual-nature complex interaction activates silent genes synthesizing novel compounds mainly with antifungal and medicinal properties, showcasing its potential for diverse applications in various fields such as agriculture and crop protection, bioremediation, environmental biotechnology, food science and fermentation, industrial biotechnology, and medical biotechnology and health. The use of Aspergillus and Bacillus species has evolved from simple monoculture applications to more sophisticated co-cultures and has been trending toward their synergy and metabolic optimization.

Neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), affect millions of people worldwide. While considerable progress has been made to elucidate the pathogenesis of these diseases in recent years, their specific mechanisms remain largely unknown. Many research study results have proven a certain association between the oral microbiome and neurodegenerative diseases. This review focuses on the relationship between the oral microbiome and neurodegenerative diseases, with a particular focus on the mechanisms of neuroinflammation.

Dermatophytoses is a well-known name among dermatologists due to its high prevalence among various ages of humans. It is mainly caused by skin-infecting fungi called dermatophytes. From these dermatophytes, Trichophyton indotineae is a newly virulent species with high prevalence and multidrug properties. It was first described in the Indian subcontinent as a closely genetically related strain to Trichophyton interdigitale and Trichophyton mentagrophytes, and spread quickly worldwide. Terbinafine has been utilized for the treatment of dermatophytosis caused by T. indotineae owing to the development of resistance to azole in many of its strains. Wide use of terbinafine has also induced later the development of terbinafine-resistant strains of T. indotineae. Point mutations in the squalene epoxidase (SQLE) gene, which lead to single or multiple substitutions in amino acid positions in the encoded protein (SQLE), are the main reason for antifungal resistance in T. indotineae. This review aims to determine the background of terbinafine-resistant strains of T. indotineae and where they are currently located.

Vaccination plays a critical role in public health by reducing the incidence and prevalence of infectious diseases. the efficacy of a vaccine has numerous determinants, which include age, sex, genetics, environment, geographic location, nutritional status, maternal antibodies, and prior exposure to pathogens. However, little is known about the role of gut microbiome in vaccine efficacy and how it can be targeted through dietary interventions to improve immunological responses. Unveiling this link is imperative, particularly in the post-pandemic world, considering impaired COVID-19 vaccine response observed in dysbiotic individuals. therefore, this article aims to comprehensively review how diet and probiotics can modulate gut microbiome composition, which is linked to vaccine efficacy. Dietary fiber and polyphenolic compounds derived from plant-based foods improve gut microbial diversity and vaccine efficacy by promoting the growth of short-chain fatty acids-producing microbes. On the other hand, animal-based foods have mixed effects – whey protein and fish oil promote gut eubiosis and vaccine efficacy. in contrast, lard and red meat have adverse effects. Studies further indicate that probiotic supplements exert varied effects, mostly strain and dosage-specific. interlinking diet, microbiome, probiotics, and vaccines will reveal opportunities for newer research on diet-induced microbiome-manipulated precision vaccination strategies against infectious diseases.

The rise of antibiotic-resistant bacteria poses a grave threat to global health, with the ESKAPE pathogens, which comprise Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp. being among the most notorious. The World Health Organization has reserved a group of last-resort antibiotics for treating multidrug-resistant bacterial infections, including those caused by ESKAPE pathogens. This situation calls for a comprehensive understanding of the resistance mechanisms as it threatens public health and hinder progress toward the Sustainable Development Goal (SDG) 3: Good Health and Well-being. The present article reviews resistance mechanisms, focusing on emerging resistance mutations in multidrug-resistant ESKAPE pathogens, particularly against last-resort antibiotics, and describes the role of biofilm formation in multidrug-resistant ESKAPE pathogens. It discusses the latest therapeutic advances, including the use of antimicrobial peptides and CRISPR-Cas systems, and the modulation of quorum sensing and iron homeostasis, which offer promising strategies for countering resistance. The integration of CRISPR-based tools and biofilm-targeted approaches provides a potential framework for managing ESKAPE infections. By highlighting the spread of current resistance mutations and biofilm-targeted approaches, the review aims to contribute significantly to advancing our understanding and strategies in combatting this pressing global health challenge.

Infections account for approximately 15% of human cancers worldwide. Viruses are the most predominant infectious agents and can infect and alter various types of human cells thereby leading to the development of various forms of cancer. Current studies have reported that Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HBC), human papillomavirus (HPV), Kaposi's sarcoma-associated herpesvirus (KSHV), human T-lymphotropic virus 1 (HTLV-1), Markel cell polyomavirus (MCPyV), and BK polyomavirus are the most important oncogenic viruses that are directly involved in the initiation and progression of cancer. Additionally, some recent studies have also reported that some non-oncogenic viruses, such as COVID-19 causing SARS-CoV-2, HIV and Dengue may potentially facilitate the onset of cancer. In this review, we outline the current knowledge of the molecular machinery of viral infection, and how viral oncogenic proteins play a specific role in cellular transformation as well as oncogenesis. Here, we have also discussed the available preventive and treatment approaches for viral infection and oncogenesis. This review will further help in the making of a roadmap for future research and the development of effective therapies such as precision medicine, gene therapies, vaccine development, and immunotherapy.

Lactoferrin (LF) is a glycoprotein, a member of the transferrin family, and is present in a variety of secretory fluids, including milk, saliva, tears, and mucosal secretions. Iron binding, immunological regulation, antibacterial action, and intestinal nutrition absorption are only a few of its important biological roles. Although much research has been done on human lactoferrin (hLF), LF derived from different animals is equally essential for physiology and health. Depending on the intended application and mechanism of action, goods containing LF and its peptide derivatives may be classified as medical devices under FDA rules or EU Directives. For EU and FDA regulations, a product may be categorized as a medical device if it primarily provides antimicrobial or health advantages. However, LFs are not considered as medical device when used as a food addition or supplement without particular medicinal claims. Safety and efficacy data are examined for regulatory approval in this category to guarantee its appropriate usage and usefulness in clinical settings. When utilized in various medicinal applications, including wound healing, gastrointestinal problems, and immune system stimulation, the complex nature and potential health advantages of LFs and their derivatives would be consistent with their categorization as a class II medical device. The role of LFs of several species (especially cameloids) is discussed in this paper as biological products with in particular biological activities and intended medical applications, where LF satisfies the requirements to be classified as a class II medical device.

Bacterial-cell surface display represents a novel field of protein engineering, which is grounds for presenting recombinant proteins or peptides on the surface of host cells. This technique is primarily used for endowing cellular activity on the host cells and enables several biotechnological applications. In this review, we comprehensively summarize the speciality of bacterial surface display, specifically in gram-positive and gram-negative organisms and then we depict the practical cases to show the importance of bacterial cell surface display in biomedicine and bioremediation domains. We manifest that among other display systems such as phages and ribosomes, the cell surface display using bacterial cells can be used to avoid the loss of combinatorial protein libraries and also open the possibility of isolating target-binding variants using high-throughput selection platforms. Thus, it is becoming a robust tool for functionalizing microbes to serve as a potential implement for various bioengineering purposes.

This review discusses the chemical properties, synthesis and detection, and biological functions of a molecular group of cis-2-unsaturated fatty acids, containing fatty acid carbon chains of various lengths and cis double-bond configurations, known as the diffusible signaling factor family (DSFF). Early postulation of the conserved nature of the DSFF among Gram-negative bacteria have now been challenged by the latest evidences that unraveled their presence in a various other distinct microorganisms. Over the last decade, a significant depth and breadth of understanding has been made on the multifaceted functions of DSFFs among bacteria, and their interactions with evolutionarily divergent fungi, plants insects and small animals. While the knowledge of the chemical nature and functions of DSFF within microbial systems is still developing, DSFF molecules such as BDSF, DSF, and SDSF have been found to modulate microbial virulence, cell adhesion, biofilm formation and dispersion, cell motility, and antimicrobial tolerance. Given their capacity to influence microbial ecosystems and the rapid emergence of novel DSFF-like molecules, it is critical to identify the full spectrum of DSFF members and to better understand the functions of this complex messenger system as they offer significant potential to be exploited in the development of new therapeutic strategies to combat the rising global healthcare threat of antimicrobial resistance. This narrative review therefore provides a broad picture of the DSFF quorum sensing with a core foundation built from seminal literature while highlighting the latest developments in the field.

Listeria monocytogenes (L. monocytogenes) is an opportunistic intracellular pathogen that causes listeriosis in human and leads to high mortality rate. L. monocytogenes is resistant to various antibiotics due to its ability to form biofilm. Designing a new generation of antibiotics is a very expensive and time-consuming process. Moreover, the protection of antibiotics via drug delivery system can promote their effectiveness and bioavailability. Nanomedicine can be a promising tool for treating intracellular bacteria and preventing the recurrence of infections. Nanocarriers can be employed as antibacterial agents or as a carrier for antibacterial agents. In the present review, the application of nanotechnology has been discussed for the prevention and treatment of Listeria infection. According to the studies, the application of nanomaterials can be a potential strategy to eradicate infections caused by L. monocytogenes.

There is growing evidence that microbial dysbiosis is intimately related to carcinogenesis across several types of human cancer. Neisseria gonorrhoeae is best known for causing acute exudative genitourinary infection in males. N. gonorrhoeae can also cause chronic, asymptomatic infection of the female genitourinary tract along with the oropharynx and rectum of both sexes. Epidemiological studies suggest that N. gonorrhoeae is an independent risk factor for cancer of the anus, bladder, cervix, prostate, and oropharynx. It is not clear however if this association is causal. The purpose of this review is to appraise epidemiological, experimental, and clinical data in order to understand the possible carcinogenic potential of this sexually transmitted bacterium.

Dental biofilm is a highly complicated and dynamic structure comprising not only microbial communities but also the surrounding matrix of extracellular polymeric substances (EPS), including polysaccharides, proteins, extracellular DNA (eDNA) and other biopolymers. In recent years, the important role of bacterial eDNA in dental biofilms has gradually attracted attention. In this review, we present recent studies on the presence, dynamic conformation and release of oral bacterial eDNA. Moreover, updated information on functions associated with oral bacterial eDNA in biofilm formation, antibiotic resistance, activation of the immune system and immune evasion is highlighted. Finally, we summarize the role of oral bacterial eDNA as a promising target for the treatment of oral diseases. Increasing insight into the versatile roles of bacterial eDNA in dental biofilms will facilitate the prevention and treatment of biofilm-induced oral infections.