Critical Reviews in Microbiology最新文献

The mouth houses the second largest diversity of microorganisms in the body, harboring more than 700 bacterial species colonizing the soft mucosa and hard tooth surfaces. Microbes are the cause of several health-related problems, such as dental carries, gingivitis, periodontitis, etc., in the mouth across different age groups and socioeconomic/demographic groups. Oral infections are major health problems that affect the standard of living. Compromised oral health is related to chronic conditions and systemic disorders. Microbes responsible for dental caries are acid-producing and aciduric Gram-positive bacteria (Streptococci, Lactobacilli). Gram-negative bacteria (Porphyromonas, Prevotella, Actinobacillus, and Fusobacterium) capable of growing in anaerobic environments are responsible for periodontal diseases. Due to the high prevalence of oral diseases, negative effects associated with the use of antimicrobial agents and increased antibiotic resistance in oral pathogens, suitable alternative methods (effective, economical and safe) to suppress microbes disturbing oral health need to be adopted. Side effects associated with the chemical antimicrobial agents are vomiting, diarrhea and tooth staining. Several researchers have studied the antimicrobial properties of plant extracts and phytochemicals and have used them as indigenous practices to control several infections. Therefore, phytochemicals extracted from plants can be suitable alternatives. This review focuses on the various phytochemical/plant extracts suppressing the growth of oral pathogens either by preventing their attachment to the surfaces or by preventing biofilm formation or other mechanisms.

Introduction: In 2022, the World Health Organization published a report encouraging researchers to focus on Candida spp. to strengthen the global response to fungal oral infections and antifungal resistance. In the context of innovative research, it seems pertinent to investigate the antifungal potential of natural extracts of plants and the methodology involved in the recent reports. The aim of this systematic review is to identify the current state of in vitro research on the evaluation of the ability of plant extracts to inhibit Candida spp.

Material and methods: A bibliographic search has been developed to on a 10-year period to identify which plant extracts have an antifungal effect on the Candida spp. found in the oral cavity.

Results: A total of 20 papers were reviewed and fulfilled all the selection criteria and were included in the full data analysis.

Discussion: Plants have been tested in a wide range of states - whole extracts, extraction of particular components such as flavonoids or polyphenols, or even using the plant to synthesize nanoparticles. Of forty-five plants tested, five of them did not show any effect against Candida spp., which weren't part of the same family. There is a wide range of plant that exhibit antifungal proprieties.

Conclusion: Many plants have been tested in a wide range of states - whole extracts, extraction of components such as flavonoids or polyphenols, or even using the plant to synthetize nanoparticles. The combination of plants, the addition of plants to a traditional antifungal and the interference with adhesion provided by some plants seem to be promising strategies. Nonetheless, on contrary to drugs, there is a critical lack of standardization on methodologies and protocols, which makes it difficult to compare data and, consequently, to conclude, beyond doubts, about the most promising plants to fight Candida spp. oral infections.

Autophagy is a crucial immune defense mechanism that controls the survival and pathogenesis of M. tb by maintaining cell physiology during stress and pathogen attack. The E3-Ub ligases (PRKN, SMURF1, and NEDD4) and autophagy receptors (SQSTM1, TAX1BP1, CALCOCO2, OPTN, and NBR1) play key roles in this process. Galectins (LGALSs), which bind to sugars and are involved in identifying damaged cell membranes caused by intracellular pathogens such as M. tb, are essential. These include LGALS3, LGALS8, and LGALS9, which respond to endomembrane damage and regulate endomembrane damage caused by toxic chemicals, protein aggregates, and intracellular pathogens, including M. tb. They also activate selective autophagy and de novo endolysosome biogenesis. LGALS3, LGALS9, and LGALS8 interact with various components to activate autophagy and repair damage, while CGAS-STING1 plays a critical role in providing immunity against M. tb by activating selective autophagy and producing type I IFNs with antimycobacterial functions. STING1 activates cGAMP-dependent autophagy which provides immunity against various pathogens. Additionally, cytoplasmic surveillance pathways activated by ds-DNA, such as inflammasomes mediated by NLRP3 and AIM2 complexes, control M. tb. Modulation of E3-Ub ligases with small regulatory molecules of LGALSs and TRIM proteins could be a novel host-based therapeutic approach for controlling TB.

Vibrio cholerae is a cholera-causing pathogen known to instigate severe contagious diarrhea that affects millions globally. Survival of vibrios depend on a combination of multicellular responses and adapt to changes that prevail in the environment. This process is achieved through a strong communication at the cellular level, the process has been recognized as quorum sensing (QS). The severity of infection is highly dependent on the QS of vibrios in the gut milieu. The quorum may exist in a low/high cell density (LCD/HCD) state to exert a positive or negative response to control the regulatory pathogenic networks. The impact of this regulation reflects on the transition of pathogenic V. cholerae from the environment to infect humans and cause outbreaks or epidemics of cholera. In this context, the review portrays various regulatory processes and associated virulent pathways, which maneuver and control LCD and HCD states for their survival in the host. Although several treatment options are existing, promotion of therapeutics by exploiting the virulence network may potentiate ineffective antibiotics to manage cholera. In addition, this approach is also useful in resource-limited settings, where the accessibility to antibiotics or conventional therapeutic options is limited.

Present-day healthcare employs several types of invasive devices, including urinary catheters, to improve medical wellness, the clinical outcome of disease, and the quality of patient life. Among urinary catheters, the Foley catheter is most commonly used in patients for bladder drainage and collection of urine. Although such devices are very useful for patients who cannot empty their bladder for various reasons, they also expose patients to catheter-associated urinary tract infections (CAUTIs). Catheter provides an ideal surface for bacterial colonization and biofilm formation, resulting in persistent bacterial infection and severe complications. Hence, rigorous efforts have been made to develop catheters that harbour antimicrobial and anti-fouling properties to resist colonization by bacterial pathogens. In this regard, catheter modification by surface functionalization, impregnation, blending, or coating with antibiotics, bioactive compounds, and nanoformulations have proved to be effective in controlling biofilm formation. This review attempts to illustrate the complications associated with indwelling Foley catheters, primarily focussing on challenges in fighting CAUTI, catheter colonization, and biofilm formation. In this review, we also collate scientific literature on catheter modification using antibiotics, plant bioactive components, bacteriophages, nanoparticles, and studies demonstrating their efficacy through in vitro and in vivo testing.

Antimicrobial resistance (AMR) in clinically priority pathogensis now a major threat to public health worldwide. Phages are bacterial parasites that efficiently infect or kill specific strains and represent the most abundant biological entities on earth, showing great attraction as potential antibacterial therapeutics in combating AMR. This review provides a summary of phage-inspired strategies to combat AMR. We firstly cover the phage diversity, and then explain the biological principles of phage therapy that support the use of phages in the post-antimicrobial era. Furthermore, we state the versatility methods of phage therapy both from direct access as well as collateral access. Among the direct access approaches, we discuss the use of phage cocktail therapy, phage-encoded endolysins and the bioengineering for function improvement of used phages or endolysins. On the other hand, we introduce the collateral access, including the phages antimicrobial immunity combined therapy and phage-based novel antibacterial mimic molecules. Nowadays, more and more talented and enthusiastic scientist, doctors, pharmacists, media, authorities, and industry are promoting the progress of phage therapy, and proposed more phages-inspired strategy to make them more tractable to combat AMR and benefit more people, more animal and diverse environment in "one health" framework.

Group A Streptococcus (GAS) is a major human pathogen, causing diseases ranging from mild superficial infections of the skin and pharyngeal epithelium to severe systemic and invasive diseases. Moreover, post infection auto-immune sequelae arise by a yet not fully understood mechanism. The ability of GAS to cause a wide variety of infections is linked to the expression of a large set of virulence factors and their transcriptional regulation in response to various physiological environments. The use of transcriptomics, among others -omics technologies, in addition to traditional molecular methods, has led to a better understanding of GAS pathogenesis and host adaptation mechanisms. This review focusing on bacterial transcriptomic provides new insight into gene-expression patterns in vitro, ex vivo and in vivo with an emphasis on metabolic shifts, virulence genes expression and transcriptional regulators role.

The oral microbiome, populated by a diverse range of species, plays a critical role in the initiation and progression of periodontal disease. The most dominant yet little-discussed players in the microbiome, the bacteriophages, influence the health and disease of the host in various ways. They, not only contribute to periodontal health by preventing the colonization of pathogens and disrupting biofilms but also play a role in periodontal disease by upregulating the virulence of periodontal pathogens through the transfer of antibiotic resistance and virulence factors. Since bacteriophages selectively infect only bacterial cells, they have an enormous scope to be used as a therapeutic strategy; recently, phage therapy has been successfully used to treat antibiotic-resistant systemic infections. Their ability to disrupt biofilms widens the scope against periodontal pathogens and dental plaque biofilms in periodontitis. Future research focussing on the oral phageome and phage therapy's effectiveness and safety could pave way for new avenues in periodontal therapy. This review explores our current understanding of bacteriophages, their interactions in the oral microbiome, and their therapeutic potential in periodontal disease.

In this review, we address the interplay between the complement system and host microbiomes in health and disease, focussing on oral bacteria known to contribute to homeostasis or to promote dysbiosis associated with dental caries and periodontal diseases. Host proteins modulating complement activities in the oral environment and expression profiles of complement proteins in oral tissues were described. In addition, we highlight a sub-set of bacterial proteins involved in complement evasion and/or dysregulation previously characterized in pathogenic species (or strains), but further conserved among prototypical commensal species of the oral microbiome. Potential roles of these proteins in host-microbiome homeostasis and in the emergence of commensal strain lineages with increased virulence were also addressed. Finally, we provide examples of how commensal bacteria might exploit the complement system in competitive or cooperative interactions within the complex microbial communities of oral biofilms. These issues highlight the need for studies investigating the effects of the complement system on bacterial behaviour and competitiveness during their complex interactions within oral and extra-oral host sites.

The cause of Alzheimer's disease (AD), and the pathophysiological mechanisms involved, remain major unanswered questions in medical science. Oral bacteria, especially those species associated with chronic periodontitis and particularly Porphyromonas gingivalis, are being linked causally to AD pathophysiology in a subpopulation of susceptible individuals. P. gingivalis produces large amounts of proteolytic enzymes, haem and iron capture proteins, adhesins and internalins that are secreted and attached to the cell surface and concentrated onto outer membrane vesicles (OMVs). These enzymes and adhesive proteins have been shown to cause host tissue damage and stimulate inflammatory responses. The ecological and pathophysiological roles of P. gingivalis OMVs, their ability to disperse widely throughout the host and deliver functional proteins lead to the proposal that they may be the link between a P. gingivalis focal infection in the subgingivae during periodontitis and neurodegeneration in AD. P. gingivalis OMVs can cross the blood brain barrier and may accelerate AD-specific neuropathology by increasing neuroinflammation, plaque/tangle formation and dysregulation of iron homeostasis, thereby inducing ferroptosis leading to neuronal death and neurodegeneration.