The potential effects of engineered metal oxide nanoparticles (MONPs) on bacterial nitrogen fixation are of great concern. Herein, the impact and mechanism of the increasing-used MONPs, including ...TiO2, Al2O3, and ZnO nanoparticles (TiO2NP, Al2O3NP, and ZnONP, respectively), on nitrogenase activity was studied at the concentrations ranging from 0 to 10 mg L−1 using associative rhizosphere nitrogen-fixing bacteria Pseudomonas stutzeri A1501. Nitrogen fixation capacity was inhibited by MONPs in an increasing degree of TiO2NP < Al2O3NP < ZnONP. Realtime qPCR analysis showed that the expressions of nitrogenase synthesis-related genes, including nifA and nifH, were inhibited significantly when MONPs were added. MONPs could cause the explosion of intracellular ROS, and ROS not only changed the permeability of the membrane but also inhibited the expression of nifA and biofilm formation on the root surface. The repressed nifA gene could inhibit transcriptional activation of nif-specific genes, and ROS reduced the biofilm formation on the root surface which had a negative effect on resisting environmental stress. This study demonstrated that MONPs, including TiO2NP, Al2O3NP, and ZnONP, inhibited bacterial biofilm formation and nitrogen fixation in the rice rhizosphere, which might have a negative effect on the nitrogen cycle in bacteria-rice system.
Display omitted
•MONPs inhibited nitrogenase activity of P. stutzeri A1501 both in medium and on rice root surface.•ROS induced by MONPs repressed nifA expression and enhanced membrane permeability.•Abundance and biofilm formation of P. stutzeri A1501 on root surface decrease when MONPs were added.•Nitrogen fixation and biofilm were inhibited in an increasing degree of TiO2NP < Al2O3NP < ZnONP.
Potassium (K+)-channel-based electrical signaling can coordinate microbial actions at a distance that provides an evolutionary advantage to cell communities. Electroactive cells are usually cultured ...surrounded by an electric field which provided stronger electrical signaling than the K+-mediated electrical signaling. Whether the K+ signaling also plays a role in coordinating the behavior of electroactive microorganisms has not been accurately demonstrated. Thus, we constructed a K+-channel-deficient strain ΔgsuK of Geobacter sulfurreducens to directly investigate roles of K+ signaling in electroactive biofilm formation for the first time. The ΔgsuK strain exhibited significantly inferior biofilm formation (i.e., biomass, thickness and component) and consequently showed weaker electrical performance (i.e., start-up time, current output, electrochemical catalytic behavior and charge transfer resistance) than the wild-type strain. Individual electric generation capacity and the expression of genes involved in biofilm formation and electrical performance in the single cell did not significantly change with the deletion of gsuK, indicating that K+ signaling indeed influenced the recruiting behavior of planktonic cell but not the functioning of the single cell related to biofilm formation or electric generation. This study is intended to provide an in-depth understanding of electroactive biofilm formation and serve as a basis for optimizing its electrical performance via strengthening the recruitment behavior.
Display omitted
•Deletion of gsuK from G. sulfurreducens reduced the K+ signaling.•Decreased K+ signaling restrained the biofilm formation of Geobacter.•K+ signaling affected electrical performance of biofilm but not individual cell.•K+ signaling influenced the recruiting behavior of planktonic cell of Geobacter.
Biofilm may influence bacterial susceptibility to traditional disinfectants but identifying effective natural disinfectants as alternatives remains a great challenge to researchers. The objective of ...this research was to examine antibiofilm activity of carvacrol against Pseudomonas aeruginosa and Listeria monocytogenes. It was found that different concentrations of carvacrol dramatically reduced the P. aeruginosa and L. monocytogenes biofilms developed on both the MBEC™ biofilm device and polypropylene surface. On the MBEC™ biofilm device, the biofilm reduction was 5.04 log CFU/peg at 0.06% carvacrol for P. aeruginosa, and 3.81 log CFU/peg at 0.12% carvacrol for L. monocytogenes. On the polypropylene surface, P. aeruginosa was reduced by 4.79 log CFU/cm2 at 0.06% carvacrol, and L. monocytogenes was reduced by 4.62 log CFU/cm2 at 0.12% carvacrol. Visual observations using advanced microscopy confirmed the biofilm reduction results for both bacteria. This study demonstrated that carvacrol has potential use as a natural compound to prevent P. aeruginosa and L. monocytogenes related contaminations of food contact surfaces. These findings suggest that carvacrol could be used to formulate new sanitizers able to inhibit P. aeruginosa and L. monocytogenes biofilms.
•Carvacrol could be effective to prevent food contact surface contaminations.•Carvacrol reduce biofilm dramatically.•Carvacrol may also be used as a disinfectant for disinfection procedure.•Carvacrol could be used to formulate new sanitizer to inhibit microbes.
Photodynamic inactivation (PDI) is a promising and effective non-thermal sterilization technology. This study aimed to construct the enhanced antibacterial and anti-biofilm blue light-emitting diode ...PDI with edible photosensitizer curcumin against Listeria monocytogenes cocktail, and to elucidate its antibacterial mechanism by determining the DNA integrity, protein changes, morphological alteration, virulence gene expression, etc. Results showed that the curcumin-mediated PDI inactivated >4 Log CFU/mL (>99.99%) of planktonic cells within 5 min (0.54 J/cm2) with 0.2 μM curcumin, and completely inactivated the pathogen within 5 min with 1.0 μM curcumin. Meanwhile, the PDI treatment negatively changed the architectural structure and markedly reduced the adhesion ability of the biofilms, resulting in a highly efficient eradiation. Antibacterial mechanism analysis indicated that the cytoplasmic DNA and protein not the outer membrane of the L. monocytogenes cells were the vulnerable attacking target for the curcumin-mediated PDI. Furthermore, the PDI treatment significantly down-regulated the expression of the virulence genes (inlA, hlyA and plcA) of L. monocytogenes, which would decrease the ability of adhesion, invasion and escape of L. monocytogenes. Therefore, the curcumin-mediated PDI is a valid and non-thermal technique in inactivating the planktonic and biofilm pathogens.
•Curcumin-mediated PDI presented an enhanced ability to inactivate L. monocytogenes.•Curcumin-mediated PDI changed the architecture and reduced the adhesion of biofilms.•Cytoplasmic components of cells were the main attacking target for the PDI treatment.•Curcumin-mediated PDI down-regulated the virulence genes expression of this pathogen.
This study aimed to determine the epidemiology, biofilm formation and antibiotic resistance of staphylococci collected worldwide in the context of UTIs.
This systematic review was conducted in ...accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Forty studies from 23 countries were selected for quantitative review. Electronic databases (PubMed, Scopus, Google Scholar, and Web of Sciences) were searched for articles published between 2010 and 2024 on the epidemiology, biofilm formation, and antibiotic resistance of uropathogenic staphylococci. Strict inclusion and exclusion standards were applied during the review of the articles.
Forty articles were included in this systematic review. The prevalence of uropathogenic staphylococci varies from country to country, with the pooled prevalence of S. aureus and coagulase-negative staphylococci (CoNS) being 8.71 % (95 %CI: 6.145–11.69) and 13.17 % (95 %CI: 8.08–19.27) respectively. Among CoNS isolates, S. epidermidis was the most common with 19.3 % (95 %CI: 5.88–38.05). The prevalence of methicillin-resistant S. aureus isolates increased significantly from 23 % in 2010–2015 to 47 % in 2021–2024 (p = 0.03). S. haemolyticus is the most antibiotic-resistant species in CoNS, with 45 % of isolates resistant to methicillin, 33 % to gentamicin, and 29 % to tetracycline.
Eighty-eight S. aureus strains were biofilm producers, including 35 % moderate biofilm producers and 48 % strong biofilm producers. The combined frequencies of icaA, clfA and fnbpA were 100, 99, and 89 %, respectively.
The development of antibiotic resistance and biofilm formation by staphylococci involved in UTIs explains the need for periodic regional surveillance of these infections, which poses a serious public health problem.
The global rise of multidrug-resistant bacterial infections is posing a direct threat to public health and imperiling almost every facet of contemporary medicine. The World Health Organization (WHO) ...has placed a high priority on the development of new antimicrobials that can combat three different types of bacteria, including carbapenem-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae that produce ESBLs. Pseudomonas aeruginosa is a multi-drug resistant (MDR) strain that causes disease with a higher mortality rate due to its resistance to several antibacterial medicines. Phage therapy has emerged as a novel therapeutic approach in response to the challenge posed by antibiotic resistance in P. aeruginosa strains, where antibiotics have proven ineffective. Moreover, research has shown that using antibiotics in addition to phage therapy increase the antibacterial infectivity. In this review, the immense of clinical research on phage therapy has been summarized, and the process through which phages move from laboratories to clinics and beyond has also been examined. Moreover, the most important studies on phage therapy developments, phage protein capacity to prevent infections, and the prevention of biofilm formation have been highlighted. In addition to looking at practical solutions to the different issues related to the use of phage therapy, our aim is to underline the importance of applying a variety of methodologies in cognitive and scientific studies.
Display omitted
Combining Shewanella oneidensis MR‐1 with the self‐doped conjugated polyelectrolyte CPE‐K leads to conductive networks that allow transfer of extracellular electron equivalents to an external gold ...electrode. In article 1908178, Guillermo C. Bazan and co‐workers show that 3D living biocomposites incorporating electrogenic bacteria and conductive gels can efficiently harvest biocurrent and provide a strategy to reduce barriers to charge extraction and injection in bioelectrochemical devices.
Display omitted
•Many bacterial processes, including virulence factor expression, biofilm formation, and viable but non-culturable (VBNC) cell resuscitation, are mediated by quorum sensing, and ...biofilm formation complicates the treatment of various infections.•This review discussed the relationship between quorum sensing inhibitors (QSI) with biofilms and VBNC.
Quorum sensing exists widely in all kinds of microorganisms and is a communication channel for microorganisms. Many bacterial processes, including virulence factor expression, biofilm formation, and viable but non-culturable (VBNC) cell resuscitation, are mediated by quorum sensing, and biofilm formation complicates the treatment of various infections. Foodborne pathogens can enter VBNC state in extreme environments, and pathogens in VBNC state can evade traditional detection and resuscitate under appropriate conditions, causing potential harm to human health. The disruption of quorum sensing may decisively help control biofilm formation and VBNC cell resuscitation. This review describes the quorum sensing systems of various bacteria and major fungi, and summarizes the role of bacterial quorum sensing system in biofilm formation and VBNC resuscitation. In addition, the relationship between quorum sensing inhibitors (QSI) with biofilms and VBNC is also discussed.
Bioaugmentation is an effective technology for treating wastewater containing recalcitrant organic pollutants. However, it is restricted by several technical problems, including the difficult ...colonization and survival of the inoculated bacteria, and the time-consuming start-up process. Considering the important roles of quorum sensing (QS) in regulating microbial behaviors, this study investigated the effects of N-acyl-homoserine lactones (AHLs)-based manipulation on the start-up of biofilm reactors bioaugmented with a pyridine-degrading strain Paracoccus sp. BW001. The results showed that, in the presence of two specific exogenous AHLs (C6-HSL and 3OC6-HSL), the biofilm formation process on carriers was significantly accelerated, producing thick and structured biofilms. The protein and polysaccharide contents of the extracellular polymeric substances (EPS) and soluble microbial products (SMP) in sludge were also elevated, possibly due to the increased abundance of several EPS-producing bacterial genera. Specifically, the stability and complexity of protein structures were improved. Besides the reactor running time, the AHL-manipulation was proved to be the main factor that drove the shift of bacterial community structures in the reactors. The addition of exogenous AHLs significantly increased the succession rate of bacterial communities and decreased the bacterial alpha diversity. Most importantly, the final proportions of the inoculated strain BW001 were elevated by nearly 100% in both sludge and biofilm communities via the AHL-manipulation. These findings strongly elucidated that AHL-based QS was deeply involved in biofilm formation, sludge characteristics, and microbial community construction in bioaugmented reactors, providing a promising start-up strategy for bioaugmentation technology.
Display omitted
•Biofilm formation process on carriers was accelerated by AHL-manipulation.•The exogenous AHLs improved the complexity of protein structures in EPS.•The exogenous AHLs notably decreased the bacterial alpha diversity via selection.•Higher microbial temporal turnover slope was found in the AHL-adding reactor.•AHL-manipulation facilitated the colonization of the inoculated strain in reactors.
PDF
