Microbial pathogenesis最新文献

A biofilm is a complex aggregation of microorganisms, either of the same or different species, that adhere to a surface and are encased in an extracellular polymeric substances (EPS) matrix. Quorum sensing (QS) and biofilm formation are closely linked, as QS genes regulate the development, maturation, and breakdown of biofilms. Inhibiting QS can be utilized as an effective approach to combat the impacts of biofilm infection. The impact of biofilms includes chronic infections, industrial biofouling, infrastructure corrosion, and environmental contamination as well. Therefore, a deep understanding of biofilms is crucial for enhancing public health, advancing industrial processes, safeguarding the environment, and deepening our knowledge of microbial life as well. This review aims to offer a comprehensive examination of challenges posed by bacterial biofilms, contemporary approaches and strategies for effectively eliminating biofilms, including the inhibition of quorum sensing pathways, while also focusing on emerging technologies and techniques for biofilm treatment. In addition, future research is projected to target the challenges associated with the bacterial biofilms, striving to develop new approaches and improve existing strategies for their effective control and eradication.

Salmonella spp. represent a significant etiological agent of foodborne illnesses and constitute a notable public health challenge on a global scale. Effectively managing Salmonella contamination within the food supply chain is imperative, as it represents a significant threat to public health, potentially leading to severe illnesses with fatal consequences. A novel bio-preservative agent is required to combat Salmonella food contamination during different stages of the food supply chain. Bacteriophages are acknowledged for their safety and recognized for their efficacy in bio-food preservation. Given their consumption together alongside food, it becomes pivotal to assess their potential toxicity concerning the probiotic gut microbiota. In this research, BALB/c mice were employed to evaluate the sub-chronic oral toxicity of bacteriophages targeting Salmonella. Following 28 consecutive days of sub-chronic administration of the Salmonella phage through oral means, histopathological examinations of vital organs, including the lung, kidneys, heart, liver, and intestine, revealed normal organ structures and no significant pathological abnormalities, in both the control and experimental groups. No physical or behavioural change was noticed in the experimental mice. Furthermore, the proliferation of indicative probiotic bacteria persisted unchanged even following a 24-hour incubation with the Salmonella phage. The body weight of both the control and experimental subjects, along with a comparative analysis of urine test results, exhibited no variations. Notably, the phages demonstrated no discernible impact on the probiotic microbiota, specifically the Lactobacillus and Bifidobacterium species isolated from the caecum of both mice that received treatment and those that did not. In untreated animals, the probiotic population (mean log CFU/ml) ranged from 1.9 to 2.4 log and 2.4 to 2.5 log, while in treated mice, it ranged from 2.0 to 2.3 log and 2.3 to 2.4 log for the Lactobacillus and Bifidobacterium species, respectively. The results of the investigation indicate that the oral administration of the lytic Salmonella phage showed no observable adverse effects on the animals, indicating an absence of harm.

The invasion of host cells by bacteria, leading to intracellular infections, is a major cause of infection recurrence. Drug-resistant Acinetobacter baumannii (A. baumannii) is one of the most challenging public health issues worldwide, with very limited clinical treatment options available. A. baumannii has been found to be able to invade host cells and proliferate within them in recent studies. In addition to the direct antimicrobial effect of antibiotics, the activation of host autophagic flux also plays an important role in eliminating intracellular pathogens. Herein, this study aimes to evaluate the clearance effect of antibiotics on intracellular A. baumannii both in vivo and in vitro, and explore the relationship between this effect and autophagy. The results showed that intracellular pathogens resulted in a significant increase in the minimum bactericidal concentration, while azithromycin can significantly eliminate intracellular A. baumannii in vitro and in vivo. Notably, 60 μg/mL azithromycin demonstrated intracellular clearance against multidrug-resistant A. baumannii and markedly induced autophagosomes in BEAS-2B cells with a mild stimulation of autophagosomes degradation. These findings indicated that azithromycin can significantly clear intracellular A. baumannii and its ability to clear intracellular A. baumannii may be related to the stimulation of autophagosome formation and the induction of host autophagy, which has important implications for the clinical treatment of A. baumannii infections, especially when intracellular infections are present.

Enteropathogenic Escherichia coli (EPEC) is a gastrointestinal pathogen that affects individuals of all age groups, with infections ranging from subclinical colonization to acute or persistent diarrhea. The bacterium's ability to cause diarrhea depends on the locus of enterocyte effacement (LEE) pathogenicity island. Although regulation of the LEE has been systematically characterized, until the last decade, these studies were limited to transcriptional control. Posttranscriptional regulation of the LEE is an underappreciated and understudied area of gene regulation. In the past few years, multiple reports have shed light on the roles of RNA-binding proteins, such as Hfq and CsrA, that modulate virulence in EPEC. This study was undertaken to explore the role of another RNA chaperone protein, ProQ, in the pathophysiology of EPEC. Our results suggest that deletion of proQ globally derepresses gene expression from the LEE in lysogeny broth (LB) suggesting that ProQ is a negative regulator of the LEE. Further interrogation of the role of ProQ in regulating the LEE-encoded type III secretion system revealed that ProQ globally silences the LEE by downregulating the expression of PerC - a prominent transcriptional activator of the LEE master regulator ler, which, in turn leads to the observed repression from the other LEE operons. Furthermore, ProQ appears to moonlight as it affects other physiological processes including type IV pili biogenesis, flagellar-motility, biofilm formation, tryptophan metabolism, and antibiotic resistance. Our study provides the very first evidence to implicate ProQ as a pleiotropic regulator in EPEC.

The present study aimed to environmentally friendly synthesis of ZnO NPs using Fioria vitifolia leaf extracts which provides a sustainable and green approach for production of NPs. The produced ZnO NPs were evaluated using various spectrum approaches (UV-vis, FTIR XRD, TEM and EDAX). The synthesized ZnO NPs was confirmed by UV-Visible spectroscopy exhibited a peak at 370 nm. SEM imaging revealed a flash-like and needle-like bottom morphology. Fourier-transform infrared spectroscopy (FTIR) analysis detected vibrations corresponding to alcohols, halides, and aromatics functional groups. TEM showed spherical-shaped NPs with an average diameter of 11 nm. XRD analysis exhibited distinct peaks at 2θ values of 31.7°, 34.3°, 36.2°, 47.4°, 56.6°, 62.8°, 66.4°, 67.9°, 69.1°, and 76.8°, corresponding to the crystallographic planes (100), (002), (101), (102), (110), (103), (200), (112), (201), (004), and (202) planes respectively. The antibacterial activity demonstrated significant zones of inhibition against E. coli (17±0.6 mm) and S. aureus (23.7±0.5 mm), and inhibition of biofilm formation in S. aureus and C. albicans. Additionally, S. mutans exhibited the highest sensitivity to the minimum inhibitory concentration (MIC) of ZnO NPs, with complete inhibition occurring at 7.5 μg/mL. Furthermore, antioxidant DPPH assays exhibited IC₅₀ values of 42 μg/mL. Additionally, the anti-inflammatory properties of ZnO NPs of F. vitifolia were evaluated in-vitro using models utilizing the human red blood cells (HRBC) membrane stabilization method (MSM), and it was shown to have an MSM of 83.87% at 250 μg/mL. Furthermore, ZnO NPs exhibited anticancer activity against the MDA-MB-231 breast cancer cell line with an IC₅₀ value of 35.50 μg/mL. Toxicological evaluation of FV-ZnO nanoparticles in zebrafish (Danio rerio) embryos indicated low toxicity at maximum concentration. These is first findings suggest that ZnO NPs synthesized from F. vitifolia leaf extracts possess significant antibacterial, antioxidant, anti-inflammatory, and anticancer properties. Additionally, their low toxicity in zebrafish embryos makes them suitable for further development in antimicrobial therapies with minimal side effects, offering a sustainable, biocompatible solution to tackle multidrug-resistant microbial infections.