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Emerging Microbes & Infections Jun 2024, a group of multi-drug resistant, Gram-positive, aerobic and partially acid-fast bacteria, are emerging causes of bacterial conjunctivitis and keratitis. However, the...
, a group of multi-drug resistant, Gram-positive, aerobic and partially acid-fast bacteria, are emerging causes of bacterial conjunctivitis and keratitis. However, the pathogenesis of keratitis is largely unknown. To address this, we used New Zealand White rabbits to develop the first eye infection model and conducted tests to study the pathogenesis mechanisms of . There is increasing evidence that biofilms play a significant role in ocular infections, leading us to hypothesize that biofilm formation is crucial for effective infection. In order to look for potential candidate genes which are important in biofilm formation and keratitis. We performed genome sequencing of two ocular isolates, -PW1004 and -PW899, to identify potential virulence factors. Through and studies, we characterized their biological roles in mediating keratitis. Our findings confirmed that is an ocular pathogen by fulfilling the Koch's postulates, and using genome sequence data, we identified encoding a mycolyltransferase, as a crucial gene in biofilm formation and causing keratitis in the rabbit model. This is the first report demonstrating the novel role of mycolyltransferase in causing ocular infections. Overall, our findings contribute to a better understanding of pathogenesis and provide a potential target for treatment. Specific inhibitors targeting TmytC could serve as an effective treatment option for infections.
PubMed: 38934251
DOI: 10.1080/22221751.2024.2373317 -
Heliyon Jun 2024Current biofilm modelling of the opportunistic pathogen, (PA) in people with cystic fibrosis (PwCF) is limited in its ability to mimic the complexities of the cystic...
Current biofilm modelling of the opportunistic pathogen, (PA) in people with cystic fibrosis (PwCF) is limited in its ability to mimic the complexities of the cystic fibrosis (CF) lung environment. Recent adaptations of the Microbial Identification after Passive CLARITY Technique (MiPACT) in CF research have allowed for the direct imaging of PA biofilm spatial organization and structure in expectorated sputum. Here, we performed a comparative analysis of and within patient () measures of PA biofilms using sputa from new onset infected children with CF. MiPACT-fluorescent hybridization (FISH) and fluorescent anti-Psl monoclonal antibody (mAb) staining was performed to directly visualize PA and Psl (exopolysaccharide in PA biofilm matrix) in 11 CF sputum specimens. Corresponding PA isolates, recovered from the same sputum samples, were grown as biofilms in a glass slide chamber model, then visualized by fluorescent live-cell and anti-Psl mAb staining. We observed that PA biovolume, aggregation and Psl antibody binding (normalized per PA biovolume) in CF sputum did not correlate with the model, although a trend towards significance in the biovolume relationship was observed with the addition of sputum supernatant to the model.
PubMed: 38933957
DOI: 10.1016/j.heliyon.2024.e32424 -
Infection and Drug Resistance 2024Persistent infections caused by (), which are resistant to antibiotic treatment, pose a growing global public health concern. Biofilm formation is known to be...
BACKGROUND
Persistent infections caused by (), which are resistant to antibiotic treatment, pose a growing global public health concern. Biofilm formation is known to be associated with persistent infections due to its role in enhancing antimicrobial resistance and the tolerance of many pathogenic bacteria.
OBJECTIVE
This study aims to evaluate the biofilm formation of clinical isolates of and its impact on antibiotic eradication.
METHODS
The thickness, morphology, and structure of biofilms derived from nine strains were examined using confocal laser scanning microscopy, scanning electron microscopy, and transmission electron microscopy. Subsequently, the susceptibility of both planktonic and biofilm bacteria was assessed through the determination of minimum inhibitory concentration and minimum biofilm eradication concentration for amoxicillin, clarithromycin, levofloxacin, and tetracycline.
RESULTS
The results revealed varying biofilm thicknesses and densities among the strains, characterised by the presence of numerous filaments intertwining and connecting bacterial cells. Additionally, several cases exhibited susceptibility based on MIC measurements but resistance according to MBEC measurements, with MBEC indicating a higher resistance rate. Pearson Correlation analysis demonstrated a positive correlation between biofilm thickness and MBEC results (0 < < 1), notably significant for amoxicillin ( = 0.801, = 0.009) and tetracycline ( = 0.696, = 0.037).
CONCLUSION
Different strains of exhibit variations in their capacity to release outer membrane vesicles (OMVs) and form biofilms. Biofilm formation can influence the effectiveness of amoxicillin and tetracycline in eradicating susceptible bacterial strains.
PubMed: 38933776
DOI: 10.2147/IDR.S468126 -
Frontiers in Veterinary Science 2024An increase in chronic, non-responsive bovine respiratory disease (BRD) infections in North American feedlot cattle is observed each fall, a time when cattle are... (Review)
Review
An increase in chronic, non-responsive bovine respiratory disease (BRD) infections in North American feedlot cattle is observed each fall, a time when cattle are administered multiple antimicrobial treatments for BRD. A number of factors are responsible for BRD antimicrobial treatment failure, with formation of biofilms possibly being one. It is widely accepted that biofilms play a role in chronic infections in humans and it has been hypothesized that they are the default lifestyle of most bacteria. However, research on bacterial biofilms associated with livestock is scarce and significant knowledge gaps exist in our understanding of their role in AMR of the bacterial BRD complex. The four main bacterial species of the BRD complex, , , , and are able to form biofilms and there is evidence that at least retains this ability . However, there is a need to elucidate whether their biofilm-forming ability contributes to pathogenicity and antimicrobial treatment failure of BRD. Overall, a better understanding of the possible role of BRD bacterial biofilms in clinical disease and AMR could assist in the prevention and management of respiratory infections in feedlot cattle. We review and discuss the current knowledge of BRD bacteria biofilm biology, study methodologies, and their possible relationship to AMR.
PubMed: 38933702
DOI: 10.3389/fvets.2024.1353551 -
Viruses Jun 2024Pentasilver hexaoxoiodate (AgIO) has broad-spectrum antimicrobial efficacy, including the long-term prevention of microbial adherence, the rapid killing of planktonic...
Pentasilver hexaoxoiodate (AgIO) has broad-spectrum antimicrobial efficacy, including the long-term prevention of microbial adherence, the rapid killing of planktonic microorganisms, and the elimination of mature biofilms. This study's goal was to determine whether it may also have antiviral activity against structurally distinct viruses. AgIO was tested following ASTM E1052-20, Standard Practice to Assess the Activity of Microbicides Against Viruses in Suspension, against adenovirus type 5, murine norovirus, poliovirus type 1, SARS-CoV-2 (original), and SARS-CoV-2 (omicron) (host cells: H1HeLa, RAW 264.7, LLC-MK2, Vero E6, and Vero E6, respectively). A 0.1 g/mL AgIO suspension was prepared and the viruses were exposed for 30 min, 4 h, or 24 h. Exposure to AgIO resulted in complete kill of SARS-CoV-2 (omicron) within 30 min, as well as complete kill of both SARS-CoV-2 (original) and the murine norovirus within 4 h. AgIO showed increasing activity over time against the adenovirus, but did not achieve a 3-log reduction within 24 h, and showed no antiviral activity against the poliovirus. These results demonstrate that AgIO has antiviral activity against medically important viruses, in addition to its well-characterized antimicrobial activity, suggesting that it may be valuable in situations where the prevention or simultaneous treatment of microbes and viruses are necessary.
Topics: Antiviral Agents; Animals; Mice; Chlorocebus aethiops; Humans; SARS-CoV-2; Vero Cells; Silver Compounds; Cell Line; Poliovirus; Norovirus; RAW 264.7 Cells
PubMed: 38932251
DOI: 10.3390/v16060959 -
Viruses May 2024Bacteriophages (phages) are viruses that infect the bacteria within which their reproduction cycle takes place, a process that ends in the lysis and death of the...
Bacteriophages (phages) are viruses that infect the bacteria within which their reproduction cycle takes place, a process that ends in the lysis and death of the bacterial cell. Some phages are also able to destroy bacterial biofilms. Due to increased antibiotics resistance, , another biofilm-forming pathogen, is a problem in many parts of the world. Zinc oxide (ZnO) and other metal nanoparticles (NPs) are biologically active and also possess anti-biofilm properties. ZnO-NPs were prepared by the green synthesis method using orange peels. The vibrational peaks of the ZnO-NPs were analyzed using FTIR analysis, and their size and morphological properties were determined using scanning electron microscopy (SEM). The ability of the ZnO-NPs to reduce or eliminate biofilm alone or in combination with phages PB10 and PA19 was investigated. The cells were effectively killed in the preformed 48 h biofilms during a 24 h incubation with the ZnO-NP-phage combination, in comparison with the control or ZnO-NPs alone. The treatments on growing biofilms were most efficient in the final stages of biofilm development. All five treatment groups showed a significant biofilm reduction compared to the control group ( < 0.0001) at 48 h of incubation. The influence of the ZnO-NPs and phages on the quorum sensing system of was monitored by quantitative real-time PCR (qRT-PCR) of the autoinducer biosynthesis gene . While the ZnO-NPs repressed the gene transcription, the phages slightly activated it at 24 and 48 h of incubation. Also, the effect of the ZnO-NPs and phage PA19 on the viability of HFF2 cells was investigated and the results showed that the combination of NPs with PA19 reduced the toxic effect of ZnO-NPs and also stimulated the growth in normal cells.
Topics: Zinc Oxide; Pseudomonas aeruginosa; Biofilms; Metal Nanoparticles; Green Chemistry Technology; Bacteriophages; Anti-Bacterial Agents; Nanoparticles
PubMed: 38932188
DOI: 10.3390/v16060897 -
Viruses May 2024Filamentous bacteriophages belonging to the order , family , significantly affect the properties of Gram-negative bacteria, but filamentous phages of many important...
Filamentous bacteriophages belonging to the order , family , significantly affect the properties of Gram-negative bacteria, but filamentous phages of many important pathogens have not been described so far. The aim of this study was to examine filamentous phages for the first time and to determine their effect on bacterial virulence. The filamentous phages were detected in 15.3% of strains as individual prophages in the genome or as tandem repeats, and a slightly higher percentage was detected in the culture collection (23.8%). The phylogenetic analyses revealed 12 new genera within the family. Bacteriophages that were selected and isolated showed structural and genomic characteristics of the family and were unable to form plaques. Upon host infection, these phages did not significantly affect bacterial twitching motility and capsule production but significantly affected growth kinetics, reduced biofilm formation, and increased antibiotic sensitivity. One of the possible mechanisms of reduced resistance to antibiotics is the observed decreased expression of efflux pumps after infection with filamentous phages.
Topics: Acinetobacter baumannii; Phylogeny; Genome, Viral; Biofilms; Inovirus; Host Specificity; Anti-Bacterial Agents; Virulence; Bacteriophages; Prophages
PubMed: 38932150
DOI: 10.3390/v16060857 -
Polymers Jun 2024Nowadays, bacteria resistance to many antibiotics is a huge problem, especially in clinics and other parts of the healthcare system. This critical health issue requires...
Phloroglucinol-Based Carbon Quantum Dots/Polyurethane Composite Films: How Structure of Carbon Quantum Dots Affects Antibacterial and Antibiofouling Efficiency of Composite Films.
Nowadays, bacteria resistance to many antibiotics is a huge problem, especially in clinics and other parts of the healthcare system. This critical health issue requires a dynamic approach to produce new types of antibacterial coatings to combat various pathogen microbes. In this research, we prepared a new type of carbon quantum dots based on phloroglucinol using the bottom-up method. Polyurethane composite films were produced using the swell-encapsulation-shrink method. Detailed electrostatic force and viscoelastic microscopy of carbon quantum dots revealed inhomogeneous structure characterized by electron-rich/soft and electron-poor/hard regions. The uncommon photoluminescence spectrum of carbon quantum dots core had a multipeak structure. Several tests confirmed that carbon quantum dots and composite films produced singlet oxygen. Antibacterial and antibiofouling efficiency of composite films was tested on eight bacteria strains and three bacteria biofilms.
PubMed: 38931997
DOI: 10.3390/polym16121646 -
Pharmaceutics Jun 2024To address the challenges posed by biofilm presence and achieve a substantial reduction in bacterial load within root canals during endodontic treatment, various...
To address the challenges posed by biofilm presence and achieve a substantial reduction in bacterial load within root canals during endodontic treatment, various irrigants, including nanoparticle suspensions, have been recommended. Berberine (BBR), a natural alkaloid derived from various plants, has demonstrated potential applications in dentistry treatments due to its prominent antimicrobial, anti-inflammatory, and antioxidant properties. This study aimed to produce and characterize a novel polymeric nanoparticle of poly (lactic-co-glycolic acid) (PLGA) loaded with berberine and evaluate its antimicrobial activity against relevant endodontic pathogens, , and . Additionally, its cytocompatibility using gingival fibroblasts was assessed. The polymeric nanoparticle was prepared by the nanoprecipitation method. Physicochemical characterization revealed spheric nanoparticles around 140 nm with ca, -6 mV of surface charge, which was unaffected by the presence of BBR. The alkaloid was successfully incorporated at an encapsulation efficiency of 77% and the designed nanoparticles were stable upon 20 weeks of storage at 4 °C and 25 °C. Free BBR reduced planktonic growth at ≥125 μg/mL. Upon incorporation into PLGA nanoparticles, 20 μg/mL of [BBR]-loaded nanoparticles lead to a significant reduction, after 1 h of contact, of both planktonic bacteria and yeast. Sessile cells within biofilms were also considered. At 30 and 40 μg/mL, [BBR]-loaded PLGA nanoparticles reduced the viability of the sessile endodontic bacteria, upon 24 h of exposure. The cytotoxicity of BBR-loaded nanoparticles to oral fibroblasts was negligible. The novel berberine-loaded polymeric nanoparticles hold potential as a promising supplementary approach in the treatment of endodontic infections.
PubMed: 38931907
DOI: 10.3390/pharmaceutics16060786 -
Pharmaceuticals (Basel, Switzerland) Jun 2024has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ),...
has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ), co-encapsulated in liposomes, could be an alternative. Coating the liposomes with chitosan (Chi) could facilitate the oral administration of this nanocarrier. Liposomes were prepared using the lipid film hydration method, followed by sonication and chitosan coating via the drip technique. Characterization included particle size, polydispersity index, zeta potential, pH, encapsulation efficiency, and physicochemical analyses. The minimum inhibitory concentration and minimum bactericidal concentration were determined against ATCC 25922, NCTC 13846, and H10407 using the microdilution method. Antibiofilm assays were conducted using the crystal violet method. The liposomes exhibited sizes ranging from 116.5 ± 5.3 to 240.3 ± 3.5 nm and zeta potentials between +16.4 ± 0.6 and +28 ± 0.8 mV. The encapsulation efficiencies were 51.5 ± 0.2% for CAZ and 99.94 ± 0.1% for UA. Lipo-CAZ-Chi and Lipo-UA-Chi exhibited antibacterial activity, inhibited biofilm formation, and preformed biofilms of . The Lipo-CAZ-UA-Chi and Lipo-CAZ-Chi + Lipo-UA-Chi formulations showed enhanced activities, potentially due to co-encapsulation or combination effects. These findings suggest potential for in vivo oral administration in future antibacterial and antibiofilm therapies against CRC-inducing bacteria.
PubMed: 38931469
DOI: 10.3390/ph17060802