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Frontiers in Microbiology 2023Myxobacteria are part of the phylum Myxococcota, encompassing four orders. Most of them display complex lifestyles and broad predation profiles. However, metabolic...
Myxobacteria are part of the phylum Myxococcota, encompassing four orders. Most of them display complex lifestyles and broad predation profiles. However, metabolic potential and predation mechanisms of different myxobacteria remains poorly understood. Herein, we used comparative genomics and transcriptomics to analyze metabolic potentials and differentially expressed gene (DEG) profiles of monoculture (Mx) compared to coculture with (MxE) and (MxM) prey. The results showed that myxobacteria had conspicuous metabolic deficiencies, various protein secretion systems (PSSs) and the common type II secretion system (T2SS). RNA-seq data demonstrated that overexpressed the potential predation DEGs, particularly those encoding T2SS, the tight adherence (Tad) pilus, different secondary metabolites (myxochelin A/B, myxoprincomide, myxovirescin A1, geosmin and myxalamide), glycosyl transferases and peptidase during predation. Furthermore, the myxalamide biosynthesis gene clusters, two hypothetical gene clusters and one arginine biosynthesis clusters were highly differential expressed in MxE versus MxM. Additionally, homologue proteins of the Tad (kil) system and five secondary metabolites were in different obligate or facultative predators. Finally, we provided a working model for exhibiting multiple predatory strategies when prey on and . These results might spur application-oriented research on the development of novel antibacterial strategies.
PubMed: 37213496
DOI: 10.3389/fmicb.2023.1146523 -
ACS Applied Materials & Interfaces May 2020Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for...
Biofilm formation is most commonly combatted with antibiotics or biocides. However, proven toxicity and increasing resistance of bacteria increase the need for alternative strategies to prevent adhesion of bacteria to surfaces. Chemical modification of the surfaces by tethering of functional polymer brushes or films provides a route toward antifouling coatings. Furthermore, nanorough or superhydrophobic surfaces can delay biofilm formation. Here we show that submicrometer-sized roughness can outweigh surface chemistry by testing the adhesion of to surfaces of different topography and wettability over long exposure times (>7 days). Gram-negative and positive bacterial strains are tested for comparison. We show that an irregular three-dimensional layer of silicone nanofilaments suppresses bacterial adhesion, both in the presence and absence of an air cushion. We hypothesize that a 3D topography can delay biofilm formation (i) if bacteria do not fit into the pores of the coating or (ii) if bending of the bacteria is required to adhere. Thus, such a 3D topography offers an underestimated possibility to design antibacterial surfaces that do not require biocides or antibiotics.
Topics: Bacterial Adhesion; Biofouling; Escherichia coli; Glass; Hydrocarbons, Fluorinated; Micrococcus luteus; Nanostructures; Pseudomonas fluorescens; Silicones; Wettability
PubMed: 32142252
DOI: 10.1021/acsami.9b22621 -
Clinical Oral Investigations Nov 2023Disinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming...
OBJECTIVES
Disinfection of alginate impression materials is a mandatory step to prevent cross-infection in dental clinics. However, alginate disinfection methods are time-consuming and exert a negative impact on accuracy and mechanical properties. Thus, this study aimed to prepare disinfecting agents (CHX and AgNO) and silver nanoparticles reduced by a natural plant extract to produce a self-disinfecting dental alginate.
METHODS
Conventional alginate impression material was used in this study. Silver nitrate (0.2% AgNO group) and chlorohexidine (0.2% CHX group) solutions were prepared using distilled water, and these solutions were later employed for alginate preparation. Moreover, a 90% aqueous plant extract was prepared from Boswellia sacra (BS) oleoresin and used to reduce silver nitrate to form silver nanoparticles that were incorporated in the dental alginate preparation (BS+AgNPs group). The plant extract was characterized by gas chromatography/mass spectrometry (GC/MS) analysis while green-synthesized silver nanoparticles (AgNPs) were characterized by UV-visible (UV-vis) spectroscopy and scanning electron microscopy (SEM). An agar disc diffusion assay was used to test the antimicrobial activity against Candida albicans, Streptococcus mutans, Escherichia coli, methicillin-resistant and susceptible Staphylococcus aureus strains, and Micrococcus luteus. Agar plates were incubated at 37 ± 1 °C for 24 h to allow microbial growth. Diameters of the circular inhibition zones formed around each specimen were measured digitally by using ImageJ software.
RESULTS
Chemical analysis of the plant extract revealed the presence of 41 volatile and semi-volatile active compounds. UV-Vis spectrophotometry, SEM, and EDX confirmed the formation of spherical silver nanoparticles using the BS extract. CHX, AgNO, and the BS+AgNPs modified groups showed significantly larger inhibition zones than the control group against all tested strains. BS+AgNPs and CHX groups showed comparable efficacy against all tested strains except for Staphylococcus aureus, where the CHX-modified alginate had a significantly higher effect.
CONCLUSIONS AND CLINICAL RELEVANCE
CHX, silver nitrate, and biosynthesized silver nanoparticles could be promising inexpensive potential candidates for the preparation of a self-disinfecting alginate impression material without affecting its performance. Green synthesis of metal nanoparticles using Boswellia sacra extract could be a very safe, efficient, and nontoxic way with the additional advantage of a synergistic action between metal ions and the phytotherapeutic agents of the plant extract.
Topics: Alginates; Disinfection; Silver Nitrate; Metal Nanoparticles; Agar; Gas Chromatography-Mass Spectrometry; Silver; Plant Extracts; Staphylococcus aureus; Nanotechnology; Anti-Bacterial Agents; Microbial Sensitivity Tests
PubMed: 37775587
DOI: 10.1007/s00784-023-05277-8 -
Biotechnology For Biofuels 2020The natural production of olefins (unsaturated aliphatic hydrocarbons) by certain bacterial genera represents an alternative and sustainable source of biofuels and...
BACKGROUND
The natural production of olefins (unsaturated aliphatic hydrocarbons) by certain bacterial genera represents an alternative and sustainable source of biofuels and lubricant components. The biochemical steps of olefin biosynthesis via the ole pathway encoded by have been unraveled recently, and the occurrence of olefins has been reported for several Gram-negative and Gram-positive bacteria. However, the distribution and diversity of olefins among the Gram-positive bacteria has not been studied in detail.
RESULTS
We report the distribution of olefin synthesis gene clusters in the bacterial domain and focus on the olefin composition and the determinants of olefin production within the phylum of . The olefin profiles of numerous genera of the order were analyzed by GC/MS. We describe for the first time olefin synthesis in representatives of the genera , , , , , , , , and . By exchange of the native genes of with the corresponding genes of actinobacteria producing different olefins, we demonstrate that the olefin composition can be manipulated with respect to chain length and isomer composition.
CONCLUSIONS
This study provides a catalogue of the diversity of olefin structures found in the Our gene swapping data indicate that the olefin structures are fundamentally determined by the substrate specificity of OleA, and at the same time by the availability of a sufficient supply of suitable fatty acyl-CoA substrates from cellular fatty acid metabolism. This makes OleA of Gram-positive bacteria a promising target for structural analysis and protein engineering aiming to generate olefin chain lengths and isomer profiles which are designed to match the requirements of various industrial applications.
PubMed: 32313552
DOI: 10.1186/s13068-020-01706-y -
International Journal of Analytical... 2021and are commonly used in the traditional folk medicine to treat microbial infection. In this study, the essential oils obtained from the leaves of growing in Malaysia...
and are commonly used in the traditional folk medicine to treat microbial infection. In this study, the essential oils obtained from the leaves of growing in Malaysia and growing in Oman were analysed by head space-solid phase microextraction-gas chromatography mass spectrometry (HS-SPME-GC-MS) and screened for antimicrobial activities against (NCTC 10418), (NCTC 10662), (ATCC 9341), (NCTC 6571), and methicillin-resistant (MRSA; ATCC 33591). To compare the antimicrobial activities of extracts using different extraction methods, methanol extraction was performed to obtain crude extracts from the leaves of and for antimicrobial analysis. The HS-SPME-GS-MS analysis of the essential oils from the leaves of and identified 37 and 36 components, respectively. Essential oils from these two species had distinctive chemical component profiles, with -pinene (27.2%) as the major component of essential oil, while dl-limonene (45.2%) constitutes the major component of essential oil. Essential oils of these two species shared only six similar terpenoids compounds: -pinene, -pinene, -elemene, sabinene, elemol, and 3-cyclohexen-1-ol. Overall, the essential oils showed antimicrobial activities against all the six bacterial strains tested, with the highest antagonistic activity against and ; while, methanolic crude extracts showed the highest activities against and MRSA strains. The methanolic crude extracts demonstrated significantly higher antibacterial activity against the Gram-positive bacteria ( < 0.005); while, the essential oils of did not show significant differences between Gram-positive and Gram-negative bacteria. Future studies are needed to investigate the active compounds present in the essential oils and methanolic crude extracts that confer the selectivity in the antimicrobial activity.
PubMed: 34497647
DOI: 10.1155/2021/9937522 -
Frontiers in Immunology 2022Current studies have demonstrated that innate immunity possesses memory characteristics. Although the molecular mechanisms underlying innate immune memory have been...
Current studies have demonstrated that innate immunity possesses memory characteristics. Although the molecular mechanisms underlying innate immune memory have been addressed by numerous studies, genetic variations in innate immune memory and the associated genes remain unclear. Here, we explored innate immune memory in 163 lines of from the Drosophila Synthetic Population Resource. In our assay system, prior training with low pathogenic bacteria () increased the survival rate of flies after subsequent challenge with highly pathogenic bacteria (). This positive training effect was observed in most lines, but some lines exhibited negative training effects. Survival rates under training and control conditions were poorly correlated, suggesting that distinct genetic factors regulate training effects and normal immune responses. Subsequent quantitative trait loci analysis suggested that four loci containing 80 genes may be involved in regulating innate immune memory. Among them, , which encodes an extracellular adenosine deaminase-related growth factor, was shown to be associated with training effects. Our study findings help to elucidate the genetic architecture of innate immune memory in and may provide insight for new therapeutic treatments aimed at boosting immunity.
Topics: Animals; Drosophila; Drosophila Proteins; Drosophila melanogaster; Immunologic Memory; Quantitative Trait Loci
PubMed: 35990631
DOI: 10.3389/fimmu.2022.857707 -
Joint Diseases and Related Surgery 2022The purpose of the study was to validate the risk of patients' exposure to pathogenic flora carried on hands of students, visitors, and patients themselves, analyzing...
OBJECTIVES
The purpose of the study was to validate the risk of patients' exposure to pathogenic flora carried on hands of students, visitors, and patients themselves, analyzing its density and genera and to compare them with the microflora of healthcare workers (HCWs).
PATIENTS AND METHODS
Between May and June 2018, five groups of participants were included. Each group consisted of eight individuals. Palmar skin imprints were obtained from dominant hands of doctors, nurses, students, visitors, and patients in orthopedics ward. Imprints were incubated at 37°C under aerobic conditions, and colony-forming units (CFU) on each plate were counted after 24, 48, and 72 h. Microorganisms were identified.
RESULTS
Hands of doctors were colonized more often by Gram - positive non-spore-forming rods bacteria than hands of nurses (p<0.05). A higher number of Staphylococcus epidermidis CFUs was observed on doctors' than on nurses' hands (p<0.05), whereas Staphylococcus hominis was isolated from doctor's and patients' imprints, but was not from nurses' and students' imprints (p<0.05). Micrococcus luteus colonized patients' hands more often than students' (p<0.05), visitors' hands than doctors' (p<0.05), students' than nurses' (p<0.05), visitors' than nurses' (p<0.05) and patients' hands (p<0.05). Staphylococcus aureus (S. aureus) was isolated only from one doctor and one nurse (203 and 10 CFUs/25 cm ). Imprints taken from the hands of patients, students and visitors were S. aureus-free. No methicillin-resistant S. aureus (MRSA), vancomycin-resistant enterococci, nor expanded spectrum betalactamase-positive or carbapenemase-positive rods were isolated. The number of Gram-negative rods was the highest on visitors' hands, significantly differing from the number on patient's, doctor's, nurse's, and student's hands. Spore-forming rods from genus of Bacillus were isolated from representatives of all tested groups. Bacillus cereus occurred more commonly on visitors' hands than doctors' hands (p<0.05).
CONCLUSION
Patients, students, and visitors may play the causal role in the spread of pathogenic bacteria, particularly spore-forming rods. Our study results confirm the effectiveness of educational activities, that is the hospital's hand hygiene program among HCWs, patients, and visitors. Hand hygiene procedures should be reviewed to put much more effort into reducing the impact of all studied groups on the transmission of infectious diseases.
Topics: Hand Hygiene; Humans; Methicillin-Resistant Staphylococcus aureus; Staphylococcal Infections; Staphylococcus epidermidis; Tertiary Care Centers
PubMed: 35852191
DOI: 10.52312/jdrs.2022.556 -
Molecules (Basel, Switzerland) Nov 2022The growing problem of antibiotic resistance among bacteria requires searching for new therapeutic agents with bacteriostatic and/or bactericidal properties. Crotoxin is...
The growing problem of antibiotic resistance among bacteria requires searching for new therapeutic agents with bacteriostatic and/or bactericidal properties. Crotoxin is a β-neurotoxin from the venom of the It is composed of two subunits: CA (non-active) and CB (with phospholipase A activity). It has already been shown that the isolated CB, but not the CA, subunit of crotoxin exhibits an antibacterial activity towards a variety of Gram-positive and Gram-negative bacterial species. However, no studies on the whole crotoxin complex have been carried out so far. We tested the antibacterial properties of crotoxin, as well as its isolated CB subunit, towards ATCC 25923, ATCC 6535, ATCC 10240, ATCC 25922, ATCC 8739, and ATCC 10145. Both toxins exhibited antibacterial properties only against ATCC 10240. Crotoxin showed only bacteriostatic activity with a MIC of 46 µM, while the CB subunit acted as both a bacteriostatic and bactericidal agent with a MIC = MBC = 0.21 μM. The bacteriostatic effect of the toxins was independent of the enzymatic activity of the CB subunit. Bactericidal properties, however, require phospholipase A activity. Both toxins reduced bacteria viability at the MIC by 72% and 85% for crotoxin- and CB-treated bacteria, respectively. The membrane permeability increased approximately three times within the first hour of incubation with toxins; afterwards, either no significant changes or a decrease of membrane permeability, compared to the control cells, were observed. We isolated a single, approximately 30 kDa bacterial wall protein which belongs to the NlpC/P60 family that interacts with crotoxin leading to the inhibition of bacterial growth. Neither crotoxin nor the CB subunit showed any cytotoxic properties to human fibroblasts at the MIC during the three-day incubation.
Topics: Animals; Humans; Crotoxin; Crotalus; Phospholipases A2; Anti-Bacterial Agents; Escherichia coli
PubMed: 36431827
DOI: 10.3390/molecules27227726 -
Turkish Journal of Pharmaceutical... Dec 2022Benth. (OS) is a commonly used medicinal plant for curbing bacterial infections globally. This work aimed to fabricate poloxamer and chitosan-based gels loaded with...
OBJECTIVES
Benth. (OS) is a commonly used medicinal plant for curbing bacterial infections globally. This work aimed to fabricate poloxamer and chitosan-based gels loaded with standardized aqueous-ethanolic OS leaf extracts and investigate their antimicrobial efficacy as a potential remedy against ocular infections.
MATERIALS AND METHODS
gels containing 0.5% w/v OS extract prepared using cold dispersion method were subjected to physicochemical characterization, including -release studies. Antimicrobial efficacy was tested against , and using agar diffusion method.
RESULTS
Thin layer chromatography and high performance liquid chromatography chromatograms confirmed the presence of rosmarinic acid (RA) and sinensitin in OS extracts with same retention factor (0.26 and 0.49) and retention times (12.2 and 20.7 min) against reference standards. A homogenous brown coloured gel exhibited low viscosity as a solution and increased viscosity in gel form at ocular temperature. The optimized formulations, P7 (21% P407/4% P188), P8 (21% P407/5% P188) and F5 (1.5% chitosan and 45% -glycerophosphate) exhibited ideal ocular pH (7.27-7.46), phase transition at ocular temperature (33-37°C) and prolonged RA release up to 12 h. Formulation F5 showed an inhibition zone of 4.3 mm against .
CONCLUSION
Among all, formulation F5 alone exhibited modest antimicrobial activity against . OS extracts at 5% and 10% were most active against tested bacteria however, loading them into gels resulted in sedimentation. Hence, isolation of RA from OS extract is suggested before loading into formulations for a better antimicrobial activity.
PubMed: 36544377
DOI: 10.4274/tjps.galenos.2021.40121 -
Graefe's Archive For Clinical and... Aug 2022Increased ophthalmology-specific risk of novel coronavirus 2019 (SARS-CoV-2) transmission is well-established, increasing the fear of infection and causing associated...
PURPOSE
Increased ophthalmology-specific risk of novel coronavirus 2019 (SARS-CoV-2) transmission is well-established, increasing the fear of infection and causing associated decreased rates of procedures known to save vision. However, the potential transmission from exposure to clinic instrumentation is unknown, including which additional pathogens may be spreading in this context. This study seeks to fill this gap by characterizing the microbiota of instrumentation in ophthalmology clinics during the COVID-19 pandemic and identifying potential sources of pathogenic spread encountered by patients and healthcare workers.
METHODS
Thirty-three samples were captured using standard cultures and media. Ten positive and negative controls were used to confirm proper technique. Descriptive statistics were calculated for all samples. Samples were collected from the retina (N = 17), glaucoma (N = 6), cornea (N = 6), and resident (N = 4) clinics with rigorous disinfection standards at a tertiary academic medical center. Standard media cultures and/or polymerase chain reaction (PCR) was performed for each sample.
RESULTS
From 33 samples, more than half (17/33, 51.5%) yielded bacterial growth. Using two different molecular methods, three samples (3/33, 9%) tested positive for SARS-CoV-2 (cycle thresholds 36.48, 37.14, and 37.83). There was no significant difference in bacterial growth (95% confidence interval [95% CI]: - 0.644-0.358, p = 0.076) among different clinics (retina, glaucoma, cornea, resident). Staphylococcus (S.) epidermidis grew most frequently (12/35, 34%), followed by S. capitis (7/35, 20%), Micrococcus luteus (2/35, 5.7%), Corynebacterium tuberculostearicum (2/35, 5.7%), and Cutibacterium ([C.], Propionibacterium) acnes (2/35, 5.7%). C. acnes growth was more frequent with imaging device forehead rests (2/7, 28.6%) than other surfaces (0/26, 0%, 95% CI: 0.019-0.619, p = 0.040). No samples isolated fungus or adenovirus.
CONCLUSIONS
Most samples across subspecialty clinic instrumentation grew bacteria, and several tested positive for SARS-CoV-2. Many isolated pathogens have been implicated in causing infections such as endophthalmitis, conjunctivitis, uveitis, and keratitis. The clinical implications of the ophthalmology microbiome for transmitting nosocomial infections warrant optimization of disinfection practices, strategies for mitigating spread, and additional study beyond the pandemic.
Topics: COVID-19; Glaucoma; Humans; Microbiota; Ophthalmology; Pandemics; SARS-CoV-2
PubMed: 35355117
DOI: 10.1007/s00417-022-05639-0