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Efflux pumps are a key component in bacteria's ability to gain resistance to antibiotics. In addition to increasing efflux, new research has suggested that the antibiotic, tetracycline, may have larger impacts on bacterial membranes. Using second harmonic scattering, we monitor the transport of two small molecules across the membranes of different Gram-positive bacteria. By comparing our results to a simple kinetic model, we find evidence for changes in influx and efflux across both bacterial species. These changes, however, are probe-dependent, opening new questions about the localization of the drug's effects and the specificity of the efflux pumps involved. [ABSTRACT FROM AUTHOR]

[Display omitted] • SIPN coatings showed extremely high self-healing ability (≥ 92 % recovery rate) within just 20 s. • SIPN coatings displayed remarkable anti-fog capability and antibacterial activities (≥ 98 %). • Coating with optimal host-guest interactions showed superior mechanical stability. Dual functional coatings with anti-fog and antimicrobial performances greatly enhance the safety and reliability of medical detection devices, but are prone to mechanical damage, resulting in reduced performance and a shorter service lifespan. Herein, a semi-interpenetrating polymer network (SIPN) coating, featuring hydrophobic-hydrophilic balanced copolymers as bulk chains and host–guest inclusion compounds (HGICs) as cross-linkers, is reported, which demonstrates particularly effective anti-fog and antibacterial performances, along with a surprisingly fast self-healing capability under various scenarios. This HGIC-based coating displayed remarkable anti-fog capability over a wide temperature range from −20 ℃ to 85 ℃ and exhibited reliable antibacterial activities (≥98 %) against both gram-positive and gram-negative bacteria. Also, this coating showed extremely high self-healing ability (≥92 % recovery rate) within just 20 s, significantly outperforming traditional self-healing systems. These findings support the development of functional coatings that can highly maintain rapid self-healing performance while also providing anti-fog and antibacterial properties in medical detection devices. [ABSTRACT FROM AUTHOR]

The increasing threat of multi-resistant infectious agents and environmental toxins has led to a demand for new therapeutic and catalytic materials. In this study, C-SiO₂ (crystalline silica), Ag-SiO₂ (silver-silica), and ZnO-SiO₂ (zinc oxide-silica) nanocomposites (NCs) were synthesized through green methods and characterized by UV-visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). These silica-based nanomaterials were investigated as potential photocatalysts for the degradation of p-nitroanilines and their antibacterial and antioxidant properties. XRD analysis showed crystalline sizes of 14 nm for C-SiO₂ NPs, 18 nm for Ag-SiO₂, and 20 nm for ZnO-SiO₂ NCs. UV-visible spectroscopy revealed energy band gaps of 4.5 eV for C-SiO₂ NPs, 3.23 eV for Ag-SiO₂, and 2.84 eV for ZnO-SiO₂. FTIR analysis confirmed the formation of SiO₂ in all samples through the Si–O–Si absorption peak. SEM revealed distinct morphologies: C-SiO₂ NPs as agglomerated granular particles, Ag-SiO₂ NCs as flattened rods or sheets, and ZnO-SiO₂ as roughly spherical. Antimicrobial testing showed that ZnO-SiO₂ and Ag-SiO₂ NCs exhibited 80% and 88% antimicrobial activity against Escherichia coli and Pseudomonas, with Ag-SiO₂ also demonstrating strong activity against Staphylococcus. The minimum inhibitory concentration (MIC) of Ag-SiO₂ and ZnO-SiO₂ NCs was found to be 80%, outperforming C-SiO₂ NPs. Antioxidant activity assays showed scavenging efficiencies of 45%, 57.8%, and 71% for C-SiO₂, Ag-SiO₂, and ZnO-SiO₂ NCs, respectively, at 30 mg/ml. ZnO-SiO₂ NCs also achieved a 75% degradation rate for p-nitroanilines, while Ag-SiO₂ achieved 45%. This study demonstrates that ZnO-SiO₂ and Ag-SiO₂ NCs are effective materials for disinfection and pollutant degradation, offering an eco-friendly solution for environmental and health challenges. [ABSTRACT FROM AUTHOR]

Background: Staphylococcus aureus is a gram-positive bacterium commonly found in the nares and oropharynx of one in three individuals and has the potential to cause significant health problems. With antibiotic-resistant strains causing 11,000 deaths yearly and ~2% of the population nasally colonized with methicillin-resistant S. aureus , a search for predictive markers and associative relationships between carriage have been long-sought goals. Within our study, we leveraged monozygotic twin participants in concert with multi-site microbiome analyses to characterize the impacts of S. aureus on composition. Results: We recruited 147 monozygotic twin pairs and characterized three sites, i.e., the nares, oropharynx, and hand microbiomes, using 16S rRNA v3-v4 sequencing in addition to S. aureus carriage status. The prevalence of S. aureus was highest in the oropharynx followed by nares and hand with concordance between twin pairs highest in the nares, followed by oropharynx. The detection of S. aureus was statistically correlated with differences in microbiome composition across sites, as indicated by beta diversity and DESeq2 analyses. Microbiome composition was most similar in twins' nares that were S. aureus culture-positive concordant, whereas twins that were culture-negative concordant had the most similarity in the oropharynx. Of significance, Moraxella nonliquefacians and Capnocytophaga were inversely associated with S. aureus in the nares and oropharynx, respectively. Conclusions: This improved understanding of S. aureus colonization in nares, oropharynx, and hand microbiomes in monozygotic twin pairs is a further step towards unraveling the degree to which the microbiome is influenced by host genetics and S. aureus carriage. [ABSTRACT FROM AUTHOR]

Opportunistic pathogens are a major threat to people, especially those with impaired immune systems. Two of the most important microbes in this category are the fungus Candida albicans and Gram-positive bacteria of the genus Enterococcus , which share overlapping niches in the oral cavity, gastrointestinal and urogenital tracts. The clinical importance of oral C. albicans biofilm and its interaction with the host under immunosuppressive conditions remains largely understudied. Here, we used a mouse model of oropharyngeal candidiasis (OPC) with cortisone acetate injection on alternate days and a continuous supply of C. albicans in drinking water for three days, resulting in immunosuppression. Results showed abundant growth of resident oral bacteria and a strong C. albicans biofilm on the tongue consisting of hyphae which damaged papillae, the epidermal layer, and invaded tongue tissue with the accumulation of inflammatory cells as demonstrated by Grocott's methenamine silver and hematoxylin and eosin staining, respectively. The dispersed microbes from the oral biofilm colonized the gastrointestinal (GI) tract and damaged its integrity, disseminating microbes to other organs. Although no visible damage was observed in the kidney and liver, except increased lipid vacuoles in the liver cells, C. albicans was found in the liver homogenate. Intriguingly, we found co-occurrence of Enterococcus faecalis in the tongue, liver, and stool of immunosuppressed control and C. albicans infected organs. Targeted 16S rRNA and ITS2 amplicon sequencing of microbes from the fecal samples of mice confirmed the above results in the stool samples and revealed an inverse correlation of beneficial microbes in the dysbiosis condition. Our study shows that mucosal-oral infection of C. albicans under immunosuppressed conditions causes tissue damage and invasion in local and distant organs; the invasion may be aided by the overgrowth of the resident endogenous Enterobacteriaceae and other members, including the opportunistic pathogen Enterococcus faecalis. [ABSTRACT FROM AUTHOR]

Objectives The increasing frequency of antibiotic-resistant bacterial infections is a major public health challenge, and new antibiotic drugs are urgently needed. A rapid solution to the problem is to repurpose clinically approved compounds with antibacterial properties, such as the nucleoside analogues zidovudine (azidothymidine) or 5-fluoro-2′-deoxyuridine. Here we report the in vitro and in vivo antibacterial properties of double and triple combinations of azidothymidine or 5-fluoro-2′-deoxyuridine with uridine and/or trimethoprim. Methods We determined MICs of azidothymidine and 5-fluoro-2′-deoxyuridine, alone or combined with uridine and/or trimethoprim, against a selection of Gram-negative and Gram-positive bacteria. We also measured MICs of a selection of antibiotics of different classes as a function of uridine concentration. The efficacy of azidothymidine and 5-fluoro-2′-deoxyuridine with uridine and/or trimethoprim was measured in a murine peritonitis infection model. Results The addition of uridine enhanced the in vitro antibacterial activity of azidothymidine and 5-fluoro-2′-deoxyuridine, against Gram-negative and Gram-positive bacteria, respectively. Uridine also enhanced the in vitro antibacterial activity of azidothymidine/trimethoprim and 5-fluoro-2′-deoxyuridine/trimethoprim combinations. Triple combinations containing azidothymidine, trimethoprim and uridine, showed antibacterial synergy against Gram-negative bacteria (Escherichia coli and Klebsiella pneumoniae) whereas the 5-fluoro-2′-deoxyuridine, trimethoprim and uridine combination showed synergy against the Gram-positive Staphylococcus aureus. The positive effect of uridine on the efficacy of azidothymidine/trimethoprim combination was also observed in vivo in a murine E. coli peritonitis model. Conclusions Triple combinations of these clinically approved compounds warrant further investigations as therapies to combat antibiotic-resistant infections. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial resistance represents a continuing threat to the health of patients with intra-abdominal infections (IAIs). This study aimed to provide clinicians with guidance to optimize antibiotic therapy. Methods: The clinical data and antibiotic susceptibility results of pathogens from patients with IAIs from 2017 to 2022 were retrospectively collected. The 6-year period was segmented into two stages, namely, the early (2017–2020) and recent stages (2021–2022). The distribution and antibiotic resistance of pathogens were compared between the stages. Results: In total, 5,795 pathogens were isolated from 2,283 patients diagnosed with IAIs. Gram-negative bacteria, Gram-positive bacteria, and fungi accounted for 71.0%, 21.4%, and 7.5% of the isolates, respectively. Klebsiella pneumoniae (1,037, 17.9%) was the primary isolate. The proportion of extended-spectrum β-lactamase-producing Enterobacteriaceae was 89.8% (2,028/2,259), with extended-spectrum β-lactamase-producing Escherichia coli and K. pneumoniae accounting for 27.4% and 43.2%, respectively, of all such isolates. The carbapenem resistance rates of E. coli and K. pneumoniae were 17.1% and 75.9%, respectively. Compared with that in the early stage, the imipenem resistance rate of E. coli was significantly higher in the recent stage (13.8% vs. 25.1%, p < 0.001). Among Gram-positive bacteria, 88 strains of vancomycin-resistant Enterococcus were detected, giving a resistance rate of 10.3%, and the detection rate of methicillin-resistant Staphylococcus aureus was 65.7%. Conclusions:Enterobacteriales and non-fermentative bacteria from IAIs remain highly resistant to carbapenems. The epidemiological characteristics and antibiotic resistance profiles of pathogens in various regions should be closely monitored to mitigate the appearance of drug-resistant bacteria in clinical settings. [ABSTRACT FROM AUTHOR]

Three chromomycin derivatives, chromomycins A3 (1, CA3), A5 (2, CA5), and monodeacetylchromomycin A3 (3, MDA-CA3), were identified from the soil-derived Streptomyces sp. CGMCC 26516. A reinvestigation of the structure of CA5 is reported, of which the absolute configuration was unambiguously determined for the first time to be identical with that of CA3 based on nuclear magnetic resonance (NMR) data analysis as well as NMR and electronic circular dichroism calculations. Compounds 1–3 showed potent cytotoxicity against the non-small-cell lung cancer (NSCLC) cells (A549, H460, H157-c-FLIP, and H157-LacZ) and down-regulated the protein expression of c-FLIP in A549 cells. The IC50 values of chromomycins in H157-c-FLIP were higher than that in H157-LacZ. Furthermore, si-c-FLIP promoted anti-proliferation effect of chromomycins in NSCLC cells. In nude mice xenograft model, 1 and 2 both showed more potent inhibition on the growth of H157-lacZ xenografts than that of H157-c-FLIP xenografts. These results verify that c-FLIP mediates the anticancer effects of chromomycins in NSCLC. [ABSTRACT FROM AUTHOR]

Quorum sensing (QS) plays a key role in the spoilage of food spoilage bacteria, and inhibiting the spoilage phenotype by interfering with QS has become a hot research topic in recent years. Previous studies showed that Nisin had a wide range of targets and its bacteriostatic activity focused on inhibiting Gram-positive bacteria. In this paper, we investigated the effect of Nisin at sub-MIC on virulence factors and biofilm formation of the common food spoilage bacteria Bacillus licheniformis DSM13 and Bacillus amyloliquefaciens CC178. The results showed that the amount of biofilm formation, EPS production, protease activity and amylase activity, promoter expression, and motility of the two bacteria showed different degrees of reduction, but hardly affected the normal proliferation of the bacteria; The impaired biofilm integrity and a large amount of matrix reduction were observed by SEM; The molecular docking demonstrated that Nisin non-competitively bind to the com P protein-specific of the two bacteria through hydrogen bonding sites, affecting the binding of com X to com P. These results suggested that low concentrations of Nisin effectively reduced the risk and safety hazards caused by QS of G+ and is a promising QS inhibitor. [Display omitted] • Elucidation of the mechanism of Gram-positive bacteria QS inhibition by Nisin. • Low concentrations of Nisin are effective in reducing QS system damage. • Nisin is a promising QSI. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The RNA chaperone Hfq plays a pivotal role in many bacteria, acting as a regulator of gene expression and promoting interaction between mRNA-sRNA pairs in Gram-negative bacteria. However, in Gram-positive bacteria this protein is expendable for riboregulation, and the main function of Hfq remains elusive. This work unveils a novel function for Hfq in the oxidative stress response of the human pathogen Listeria monocytogenes , a Gram-positive bacterium responsible for the infectious disease listeriosis. Disruption of hfq gene (Δ hfq) results in a hypersensitive phenotype towards hydrogen peroxide (H 2 O 2), in which sub-inhibitory concentrations of this reactive oxygen species (ROS) severely impair growth and viability of L. monocytogenes EGD-e. A Δ hfq- complemented strain does not show this phenotype. This Hfq-dependent regulation of oxidative stress seems specific for H 2 O 2 , as exposure to superoxides caused no differences. We demonstrate that Hfq has a dual regulatory role in the expression of catalase (kat), the key enzyme involved in H 2 O 2 detoxification. Hfq influences kat transcription under non-stress conditions by modulating the levels of the transcriptional repressor PerR, and also acts post-transcriptionally by stabilizing kat mRNA under H 2 O 2 -induced stress. Indeed, enzymatic assays revealed reduced catalase activity in Δ hfq cell extracts, a result unrelated to differences in cellular iron content. Bacterial infection triggers immune cells to produce massive amounts of ROS, like H 2 O 2. We show that inactivation of Hfq increases susceptibility to macrophage killing, connecting Hfq with the stress resistance and virulence of L. monocytogenes EGD-e. Overall, these findings advance the understanding of Hfq function within Gram-positive bacteria, revealing for the first time that Hfq is a novel regulator of catalase expression. This paves the way for the study of yet unknown oxidative stress response pathways regulated by Hfq in other pathogens. [Display omitted] • The RNA chaperone Hfq is a novel regulator of hydrogen peroxide oxidative stress. • Inactivation of Hfq leads to hypersensitivity to H 2 O 2 in L. monocytogenes. • Hfq is a positive post-transcriptional regulator of catalase expression. • Hfq controls the stability and levels of catalase mRNA under H 2 O 2 -induced stress. [ABSTRACT FROM AUTHOR]

Purpose: Group B streptococci (GBS) are Gram-positive bacteria that are a leading cause of neonatal infections. Most invasive isolates are β-hemolytic, and hemolytic activity is critical for GBS virulence. Although nonhemolytic GBS strains are occasionally isolated, they are often thought to be attenuated in virulence. Recent studies have observed that many nonhemolytic and nonpigmented (NH/NP) strains originated from invasive infections, including bacteremia and meningitis, in neonates or adults. The mutations causing the NH/NP phenotype are predominantly localized in the cyl operon and abx1 gene. Previous studies on group B streptococci in Taiwan have focused on the serotype and genotype distribution. In this study, we investigated the serotype distribution of the NH/NP strains and detected the mutations of abx1. Methods: One hundred clinical GBS strains from non-invasive (vaginal and rectal swabs, 69) and invasive infections (blood, urine and abscess, 31), including 10 NH/NP isolates, were collected during 2019–2021 at Fooyin University Hospital. To confirm GBS isolates, we have developed a multiplex PCR method that detects GBS isolates, virulent strain ST-17 and virulent factor Srr1 simultaneously. Molecular serotyping was performed by multiplex PCR assay using serotype specific primer sets. The genomic region containing abx1 was amplified from DNA extracts by PCR and the amplicons were directly sequenced and analyzed on an ABI prism 3730 DNA analyzer. Results: The capsular serotypes III and VI were the most abundant in both the non-invasive specimens and invasive specimens. The ST-17 isolates were more frequently associated with invasive infections (16.1%, 5/31) than non-invasive diseases or colonization (7.2%, 5/69). The association of NH/NP strains between noninvasive diseases or colonization (10.1, 7/69) and invasive infection (9.7%, 3/31) is nearly compatible. The NH/NP strains were isolated from various serotypes (Ia, III, V and VI) and five NH/NP isolates were serotype III. The virulence factor Srr1was detected in most of the NH/NP isolates (8/10) and one NH/NP isolate was ST-17. Abx1 mutations, including transitions, transversions and deletions, were observed in some NH/NP isolates, but some mutations also observed in hemolytic isolates. Five NH/NP isolates were erythromycin and clindamycin resistant. Conclusion: These results indicate NH/NP GBS strains may have the potential for invasive infections and may show higher tendency to get mutated. [ABSTRACT FROM AUTHOR]

This study aimed to determine the effects of the specific wavelength and intensity of IPL on microbial inactivation by applying IPL under various conditions with the same fluence. Nine different filters were used to obtain pulse light sources with various composition ratios in the ultraviolet (UV), visible light (VL), and infrared (IR) ranges, and the inactivation was compared among gram-positive bacteria, gram-negative bacteria, and yeast. When gram-positive bacteria were treated with a light source that accounted for 85.29% of the total wavelength in the UV range, a significant reduction of bacteria by 6 logs was achieved at the fluence of 2.16 J/cm2. However, it was noteworthy that even when UV accounted for only 11.66%, a 6-log reduction was achieved at 3.94 J/cm2. This study confirmed that the intensity of single pulses in IPL is as important as the UV range in microbial inactivation. Even if the proportion of UV in IPL is low, strong intensity of single pulses delivered to microorganisms can cause significant damage and increase inactivation. There was no significant difference in resistance to IPL between gram-positive and gram-negative bacteria, but yeast showed relatively higher resistance to IPL, and this tendency was more pronounced in IPL with higher UV content. [ABSTRACT FROM AUTHOR]

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Aims: Antibiotic resistance is currently a major challenge to scientists. Thus, attempts have been made to develop new compounds with antimicrobial activity. In this research, a new antimicrobial peptide with antibacterial activity was isolated from the plant Urtica dioica. Methods: A new antimicrobial peptide, named cliotide U1, was purified through precipitation with ammonium sulfate and reverse-phase high-performance liquid chromatography. In silico methods analyzed the physicochemical properties of cliotide U1. The properties of the peptide, including antibacterial activity, pH stability, heat stability, cytotoxicity, and hemolytic activity, were also examined. Findings: The purified peptide was composed of 35 amino acids with a hydrophobicity ratio of 63% and a net charge of + 5. The antibacterial activity of cliotide U1 was observed against gram-negative and gram-positive bacteria with a minimum inhibitory concentration (MIC) of 1 to 4 µM. Cliotide U1 had less than 2% cytotoxic activity at the MIC range against the human embryonic kidney cell line 293 with no clear hemolytic activity. The stability of cliotide U1 was preserved at various temperatures (10-60°C) and pH (6-9). Conclusion: Our results demonstrated that cliotide U1 had potent antibacterial potential against gram-negative and gram-positive bacteria. Considering its properties, cliotide U1 can be introduced as a novel antibacterial candidate for expanding new therapeutic drugs. [ABSTRACT FROM AUTHOR]

Bacterial type IV secretion systems (T4SSs) are widespread nanomachines specialized in the transport across the cell envelope of various types of molecules including mobile genetic elements during conjugation. Despite their prevalence in Gram-positive bacteria, including relevant pathogens, their assembly and functioning remain unknown. This study addresses these gaps by investigating VirB8 proteins, known to be central components of conjugative T4SSs in Gram-positive bacteria. However, the functional packing and precise role of VirB8 in T4SSs biology remain undefined. Our findings elucidate the nature of VirB8 proteins as cell wall components, where they multimerize and exhibit a conserved assembly pattern, distinct from VirB8 in Gram-negative bacteria. We also demonstrate that VirB8 proteins interact with other T4SS subunits and DNA, indicating their pivotal role in the building of the DNA translocation channel across the cell wall. We lastly propose a distinct architecture for conjugative T4SSs in Gram-positive bacteria compared to their Gram-negative counterparts, possibly attributed to the differences in the cell wall structure. [ABSTRACT FROM AUTHOR]

The Staphylococcus genus, composed of Gram-positive bacteria, includes several pathogenic species such as Staphylococcus aureus, S. epidermidis, S. haemolyticus, and S. saprophyticus, each implicated in a range of infections. This study investigates the codon usage patterns in key virulence genes, including Autolysin (alt), Elastin Binding protein (EbpS), Lipase, Thermonuclease, Intercellular Adhesion Protein (IcaR), and V8 Protease, across four Staphylococcus species. Using metrics such as the Effective Number of Codons (ENc), Relative Synonymous Codon Usage (RSCU), Codon Adaptation Index (CAI), alongside neutrality and parity plots, we explored the codon preferences and nucleotide composition biases. Our findings revealed a pronounced AT-rich codon preference, with AT-rich genomes likely aiding in energy-efficient translation and bacterial survival in host environments. These insights provide a deeper understanding of the evolutionary adaptations and translational efficiency mechanisms that contribute to the pathogenicity of Staphylococcus species. This knowledge could pave the way for novel therapeutic interventions targeting codon usage to disrupt virulence gene expression. [ABSTRACT FROM AUTHOR]

The structural and electronic behavior of thiosemicarbazone (TSC)-based metal complexes of Mn (II), Fe (II), and Ni (II) have been investigated. The synthesized metal complexes were characterized using elemental analysis, magnetic susceptibility, molar conductivity, FTIR, and UV–Vis spectroscopy, the computational path helped with further structural investigation. The solubility test on the TSC and its complexes revealed their solubility in most organic solvents. DFT computational analysis was performed, and quantum reactivity parameters of the octahedral optimized complexes were calculated to describe the reactivity via the stability states of the synthesized complexes. FMOs map was generated to confirm similar findings and MEP analysis was applied to elaborate the important electrophilic and nucleophilic sites on the studied surfaces. Also, other important topological analyses such as electron localization function and reduced density gradient, to establish the favorable noncovalent interactions, were studied. In silico molecular docking approach was studied against the gram-positive bacteria Bacillus cereus to predict the potent inhibition behavior of the studied complexes. The findings summarized the inhibition prediction of the most interactive [NiL2Cl2], then [FeL2Cl2] complexes as confirmed by the binding energy values (− 7.1 kacl/mol and − 6.4 kacl/mol, respectively). Another In silico results, with gram-positive bacteria (S. aureus), estimated similar results of the experimental finding, where [MnL2Cl2] (− 9.2 kcal/mol) is the more effective predicted antibacterial inhibitor. Fluorescence microscopy was used to examine the inhibition of bacterial biofilm, and the DPPH assay was used to measure antioxidant activity, followed by an understanding of the behavior of the current complexes toward free radicals' removal. The findings observed less aggregated bacterial strains covered with the studied complexes leading to less dense biofilm covering. [ABSTRACT FROM AUTHOR]

The oxidation states of vanadium determine its mobility and toxicity, and dissimilatory vanadate reduction has been reported in several microorganisms, highlighting the potential significance of this pathway in the remediation of vanadium contamination and the biogeochemical cycle. However, to date, most known microorganisms capable of reducing vanadate are Gram-negative respiratory bacteria belonging to the phylum Proteobacteria. In this study, we isolated Tepidibacter mesophilus strain VROV1 from deep-sea sediments on the northern Central Indian Ridge and investigated its ability to reduce vanadium and the impact of vanadate on its cellular metabolism. A series of culture experiments revealed that the isolated strain efficiently reduces V(V) to V(IV) during fermentation, even at mM levels, and this reduction involves a direct biological process rather than indirect reduction via metabolic products. Vanadium affects microbial carbon and nitrogen metabolism. Notably, in the presence of vanadate, alanine production decreases, suggesting that metabolic flux is diverted from the transamination reaction to vanadate reduction. T. mesophilus VROV1 is the second Gram-positive bacterium identified to reduce vanadium, following Lactococcus raffinolactis, but these bacteria belong to different classes: T. mesophilus is classified as Clostridia, whereas L. raffinolactis is classified as Bacilli. The specific rate of vanadate removal by VROV1 was as high as 2.8 pmol/cell/day, which is comparable to that of metal-reducing bacteria and markedly exceeds that of L. raffinolactis. Our findings expand the distribution of vanadate-reducing organisms within the bacterial domain. Given the wide range of natural habitats of T. mesophilus and its close relatives, we speculate that fermentative vanadate reduction may have a greater impact on the global biogeochemical cycle of vanadium than previously thought. [ABSTRACT FROM AUTHOR]

A sustainable biosorbent, silver nanoparticles-decorated coffee-ground waste (CWAg), was synthesized through a simple in-situ reduction method. CWAg is extensively characterized via SEM–EDX, PZC, FTIR, XRD, HR-TEM, and XPS analyses. The biosorbent was tested to remove chromium (Cr(VI)) and methylene blue (MB) from wastewater, and its antibacterial properties was evaluated. CWAg demonstrated efficient sorption efficiencies, achieving ⁓149.9 mg/g at 323 K and pH: 2.0 for Cr(VI) and ⁓113.4 mg/g at 293 K and pH: 6.0 for MB, at a biosorbent dose of 1 g/L. The equilibration times were 90 and 120 min for Cr(VI) and MB, with half-sorption times (tHST) of 9.2 and 13.9 min, respectively. The sorption mechanisms were successfully fitted with Sips isotherm and Pseudo-second-order models. Simultaneous sorption of MB and Cr(VI) at pH 2.0 exhibited antagonism, while a synergistic effect was observed at pH 6.0. Desorption and regeneration were achieved using NaOH and HCl solutions for Cr(VI) and MB, respectively. The efficiencies were just reduced by 9–13%. Finally, CWAg exhibited remarkable effectiveness for removing Cr(VI) from complex tannery effluent. Moreover, CWAg demonstrated positive antibacterial effects against both Gram-positive and Gram-negative bacteria, surpassing raw coffee-ground waste, underscoring the significant role of silver nanoparticles in enhancing bacterial inhibition. [ABSTRACT FROM AUTHOR]

Reducing the use of antibiotics in animal husbandry is essential to limit the spread of resistance. A promising alternative to antibiotics resides in bacteriocins, which are antimicrobial peptides produced by bacteria showing a great diversity in terms of spectrum of activity, structure, and mechanism of action. In this study, the effects of diverse bacteriocins on the composition and metabolic activity of chicken cecal microbiota were examined in vitro, in comparison with antibiotics. Different impacts on microbiota composition were revealed by 16S metabarcoding, with colistin having the most dramatic impact on diversity. Bacteriocins produced by Gram-negative bacteria, microcins J25 and E492, did not significantly influence the microbiota composition. In contrast, bacteriocins from Gram-positive bacteria impacted the abundance of lactic acid bacteria, with nisin Z showing the most impact while pediocin PA-1 (M31L) exhibited a moderate effect at the highest concentration tested. This study emphasizes the potential of bacteriocins as alternatives to antibiotics in poultry to protect from pathogens such as Salmonella, Clostridium, and Enterococcus. [ABSTRACT FROM AUTHOR]

Biocontrol microbes are environment friendly and safe for humans and animals. To seek biocontrol microbes effective in suppressing Fusarium oxysporum is important for tomato production. F. oxysporum is a soil-borne pathogen capable of causing wilt in numerous plant species. Therefore, we found a biocontrol bacterium with an excellent control effect from the rhizosphere soil of plant roots. In this work, we focus on two parts of work. The first part is the identification and genomic analysis of the biocontrol bacterium Y-4; the second part is the control efficiency of strain Y-4 on F. oxysporum. For this study, we identified strain Y-4 as Bacillus velezensis. It is an aerobic Gram-positive bacterium that can secrete a variety of extracellular enzymes and siderophores. Strain Y-4 also contains a large number of disease-resistant genes and a gene cluster that forms antibacterial substances. In addition, we found that it significantly inhibited the reproduction of F. oxysporum in a culture dish. In the indoor control effect test, after treatment with strain Y-4 suspension, the disease index of tomato plants decreased significantly. Furthermore, the control efficiency of the plants was 71.88%. At the same time, Y-4 bacterial suspension induced an increase in POD and SOD enzyme activities in tomato leaves, resulting in increased plant resistance. Taken together, strain Y-4 proves to be an effective means of controlling F. oxysporum in tomatoes. [ABSTRACT FROM AUTHOR]

Taurine is essential for sustaining the body's physiological equilibrium and is extensively utilized as a dietary supplement and immune system enhancer for aquatic creatures. The gut microbiota serves as a vital health indicator in animals. In this study, our goal was to evaluate the effects of dietary taurine on the gut microbiome of Chinese stripe-necked turtles (Mauremys sinensis). Turtles were evenly divided into three supplementation groups: a control group with no taurine in the diet, a low group with 0.1% taurine, and a high group with 0.4% taurine. High-throughput sequencing was employed to analyze the gut microbiome's composition and structure. The results showed that the impact of taurine supplementation on the α-diversity and β-diversity of the gut microbiome was not statistically significant. At the phylum level, Firmicutes and Bacteroidetes predominated the gut microbiome. At the genus level, three beneficial bacteria, Clostridium_sensu_stricto_13, Pygmaiobacter, and Terrisporobacter showed significant differences under different levels of taurine supplementation and increased in abundance with the supplementation of taurine, while the harmful bacterium Brucella decreased in abundance with the addition of taurine and exhibited significant differences. Furthermore, LEfSe analysis and functional predictions highlighted significant variations in the functional traits of gram-positive intestinal bacteria among the different taurine supplementation levels. These findings imply that dietary taurine may alter the intestinal microbiome structure in Chinese stripe-necked turtles, offering valuable insights for the scientific assessment of taurine's health benefits as a feed additive and potentially guiding the formulation of more informed and healthier feeding practices. [ABSTRACT FROM AUTHOR]

The volatile compositions and antimicrobial activity of aerial parts of Popowia pisocarpa from Vietnam were reported for the first time. From the GC/MS spectral, spathulenol (35.9%), bicyclogermacrene (5.7%) and muurola-4,10(14)-dien-1β-ol (4.2%) among the sesquiterpenoids, along with 4,4-dimethyl-3-(3-methylbut-3-enylidene)-2-methylenebicyclo[4,1,0]heptane (17.7%), an unsaturated cyclic compound, were the main constituents of the essential oil. Monoterpenoids were not identified in the essential oil. The essential oil displayed antimicrobial activity against the Gram-negative Escherichia coli ATCC 25922 with MIC value of 16.0 µg/mL and IC50 value of 8.52 µg/mL. In addition, the essential oil also exhibited activity towards the Gram-positive bacteria of Staphylococcus aureus ATCC 13709, Bacillus subtilis ATCC 6633, and Lactobacillus fermentum N4 with MIC value of 64.0 µg/mL each and corresponding IC50 values of 11.06 µg/mL, 26.47 µg/mL and 15.68 µg/mL, respectively. The essential oil did not inhibit the growth of Pseudomonas aeruginosa ATCC 15442, Salmonella enterica and the yeast Candida albicans ATCC 10231. [ABSTRACT FROM AUTHOR]

Introduction: Turpentine derivatives and eucalyptus oil are herbal substances traditionally used to treat various skin infections. Limited non-clinical data suggest they exert an immunological activity, but only scant information exists on their antibiotic effects. This in vitro study has been carried out to investigate the antibacterial and antifungal activity of a marketed skin ointment; its active pharmaceutical ingredients larch turpentine, eucalyptus oil, and turpentine oil; and their mixture, against bacteria and yeasts commonly present on the skin and causing skin infections. Methods: The antibiotic activity was tested using the drop dilution assay on the Gram-positive bacteria Staphylococcus aureus (wild type), a methicillin-resistant S. aureus strain, S. epidermidis, S. haemolyticus, Streptococcus pyogenes, the Gram-negative Pseudomonas aeruginosa, and the yeasts Candida albicans and C. tropicalis. Results: The ointment exerts a strong inhibitory effect on all Gram-positive bacteria at a concentration of 5 g/100 mL in the Müller-Hinton medium. It also has inhibiting effect on both Candida species but does not inhibit P. aeruginosa growth. As for the single active pharmaceutical ingredients, larch turpentine was the most active substance. The mixture of the three ingredients, in the concentrations used in the ointment, had a higher antibiotic effect than any of the individual ingredients studied, suggesting at least an additive activity. Conclusions: Our study has shown that the herbal ingredients and their combination exert antimicrobial activities, especially against Gram-positive bacteria, that justify their use in the treatment of skin infections. [ABSTRACT FROM AUTHOR]

Gram-positive bacterial pneumonia is a significant cause of hospitalization and death. Shortage of a good experimental model and therapeutic targets hinders the cure of acute lung injury (ALI). This study has established a mouse model of ALI using Gram-positive bacteria Lactobacillus casie cell wall extracts (LCWE) and identified the key regulator NLRP3. We show that LCWE induces TNF, NF-κB signaling, and so on pathways. Similar to lipopolysaccharide (LPS), LCWE induces the infiltration of CD11b-positive cells and inflammation in lungs. LCWE also triggers inflammatory signaling through TLR2, different from LPS through TLR4. It suggests that cytokines amplify inflammation signaling relying on NLRP3 in LCWE-induced ALI. NLRP3 deletion disrupts inflammation, IL-1β cleavage, and the infiltration of neutrophils and macrophages in the injured lung. Our study highlights an animal ALI model for Gram-positive bacterial pneumonia and that NLRP3 is a key therapeutic target to prevent inflammation and lung damage in LCWE-induced ALI. NLRP3 drives inflammatory signaling and cleaved IL-1β in a mouse model of acute lung injury induced by Lactobacillus casei cell wall extracts, highlighting its role as a therapeutic target in Gram-positive bacterial pneumonia. [ABSTRACT FROM AUTHOR]

Pathogenic bacteria trigger complex molecular interactions in hosts that are characterized mainly by an increase in reactive oxygen species (ROS) as well as an inflammation-associated response. To counteract oxidative damage, cells respond through protective mechanisms to promote resistance and avoid tissue damage and infection; among these cellular mechanisms the activation or inhibition of the nuclear factor E2-related factor 2 (Nrf2) is frequently observed. The transcription factor Nrf2 is considered the master regulator of several hundred cytoprotective and antioxidant genes. Under normal conditions, the Keap1/Nrf2 signaling protects the cellular environment by sensing deleterious oxygen radicals and inducing the expression of genes coding for proteins intended to neutralize the harmful effects of ROS. However, bacteria have developed strategies to harness Nrf2 activity to their own benefit, complicating the host response. This review is aimed to present the most recent information and probable mechanisms employed by a variety of bacteria to modulate the Keap1/Nrf2 activity in order to survive in the infected tissue. Particularly, those utilized by the Gram-positive bacteria Staphylococcus aureus , Streptococcus pneumoniae , Listeria monocytogenes , and Mycobacterium tuberculosis as well as by the Gram-negative bacteria Escherichia coli , Helicobacter pylori , Legionella pneumophila , Pseudomonas aeruginosa and Salmonella typhimurium. We also discuss and highlight the beneficial impact of the Keap1/Nrf2 antioxidant and anti-inflammatory role in bacterial clearance. [ABSTRACT FROM AUTHOR]

Thiamine dilauryl sulphate (TDS) exerts a bacteriostatic effect against Gram-positive bacteria and is used as a food additive. The heartwood extract of the Indian kino tree (Pterocarpus marsupium), a medicinal tree native to India, shows weak antimicrobial effects against bacteria and superficial dermatophyte-infective fungi. Herein, we report that the combination of TDS and P. marsupium extract exerts an additive or synergistic antimicrobial effect against various food spoilage microorganisms. Among the 13 species tested, this combination showed synergistic antimicrobial effects against Bacillus subtilis, Lactococcus lactis, Lactobacillus plantarum , and Candida albicans in an agar dilution method. We also found that the combination promoted the production of reactive oxygen species against a model yeast Saccharomyces cerevisiae using a fluorescnt 2′,7′-dichlorofluorescein diacetate. Furthermore, the combination restricted drug efflux from yeast cells via efflux pumps in an efflux assay using a fluorescent rhodamine 6 G. These results suggest that the antifungal effect of TDS is improved in combination with P. marsupium extract via oxidative stress induction and drug efflux restriction. The combination of TDS and P. marsupium extract has a low environmental impact and toxicity when used in foods; therefore, it is also expected to be used in food and industrial products in the future. [ABSTRACT FROM AUTHOR]

Objective: To assess the antibacterial and antifungal activity in vitro of a patented Spirulina extract on sensitive and multidrug-resistant bacteria, yeasts, and filamentous fungi commonly causing skin infections. Methods: The antimicrobial activity was tested using the drop dilution assay on the Gram-positive bacteria Staphylococcus aureus (wildtype), a methicillin resistant S. aureus, S. epidermidis, S. haemolyticus, Streptococcus pyogenes, the Gram-negative multidrug resistant Pseudomonas aeruginosa, the yeasts Candida albicans and C. tropicalis, and the dermatophytes Trichophyton rubrum and Microsporum gypseum. Results: A concentration of 4 g of Spirulina extract per 100 mL of Mueller Hinton agar completely inhibited the growth of all tested bacteria and yeasts, and suppressed dermatophytes growth by 5 log10 units. Conclusion: The Spirulina extract tested could be used as an effective natural, broad-spectrum antimicrobial agent, with potential applications in the therapy of bacterial and fungal infectious diseases. [ABSTRACT FROM AUTHOR]

Biosurfactants/bioemulsifiers (BSs/BEs) can be defined as surface-active biomolecules produced by microorganisms with a broad range of applications. In recent years, due to their unique properties like biodegradability, specificity, low toxicity, and relative ease of preparation, these biomolecules have attracted wide interest as an eco-friendly alternative for several industrial sectors, escalating global microbial BS/BE market growth. Recently, Gordonia alkanivorans strain 1B, a bacterium with significant biotechnological potential, well known for its biodesulfurizing properties, carotenoid production, and broad catabolic range, was described as a BS/BE producer. This study focuses on the characterization of the properties of the lipoglycopeptide BSs/BEs produced by strain 1B, henceforth referred to as gordofactin, to better understand its potential and future applications. Strain 1B was cultivated in a chemostat using fructose as a carbon source to stimulate gordofactin production, and different purification methods were tested. The most purified sample, designated as extracted gordofactin, after lyophilization, presented a specific emulsifying activity of 9.5 U/mg and a critical micelle concentration of 13.5 mg/L. FT-IR analysis revealed the presence of basic hydroxyl, carboxyl, ether, amine/amide functional groups, and alkyl aliphatic chains, which is consistent with its lipoglycopeptide nature (60% lipids, 19.6% carbohydrates, and 9% proteins). Gordofactin displayed remarkable stability and retained emulsifying activity across a broad range of temperatures (30 °C to 80 °C) and pH (pH 3–12). Moreover, a significant tolerance of gordofactin emulsifying activity (EA) to a wide range of NaCl concentrations (1 to 100 g/L) was demonstrated. Although with a great loss of EA in the presence of NaCl concentrations above 2.5%, gordofactin could still tolerate up to 100 g/L NaCl, maintaining about 16% of its initial EA for up to 7 days. Furthermore, gordofactin exhibited growth inhibition against both Gram-positive and Gram-negative bacteria, and it demonstrated concentration-dependent free radical scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (IC50 ≈ 1471 mg/L). These promising features emphasize the robustness and potential of gordofactin as an eco-friendly BS/BE alternative to conventional surfactants/emulsifiers for different industrial applications. [ABSTRACT FROM AUTHOR]

Background: Listeria monocytogenes is a Gram-positive bacterium responsible for listeriosis, a serious foodborne disease that can lead to serious health complications. Pregnant women, newborns, the elderly, and patients with weakened immune systems are particularly susceptible to infection. Due to the ability of L. monocytogenes to survive in extreme environmental conditions, such as low temperatures, high salinity, and acidity, this bacterium poses a serious threat to food production plants and is particularly difficult to eliminate from these plants. One of the promising solutions to reduce the presence of this bacterium in food products is bacteriocins as natural control agents. These are substances with antibacterial activity produced by other bacteria, mainly lactic acid bacteria (LAB), which can effectively inhibit the development of pathogens such as L. monocytogenes. The use of bacteriocins in the food industry is beneficial due to their natural origin, specificity of action, and consumer safety. However, the problem of resistance to these substances exists. Results: This review focuses on the mechanisms of bacteriocin resistance, such as modifications of bacteriocin docking receptors, changes in the structure of the cell wall and membrane, and the occurrence of cross-resistance to different bacteriocins. Genetic factors determining these mechanisms and strategies to cope with the problem of resistance are also presented. Conclusions: Research on this issue is crucial for developing effective preventive methods that will enable the safe and long-term use of bacteriocins in food production. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes is a Gram-positive bacterium causing listeriosis, a severe infection responsible for significant morbidity and mortality globally. Its persistence on food processing surfaces via biofilm formation presents a major challenge, as conventional sanitizers and antimicrobials exhibit limited efficacy against biofilm-embedded cells. This study investigates a novel approach combining an engineered polysaccharide-degrading enzyme (CAase) with a bacteriocin (thermophilin 110) produced by Streptococcus thermophilus. Laboratory assays evaluated the effectiveness of this combination in disrupting biofilms and inactivating L. monocytogenes on various surfaces. The results demonstrated that CAase effectively disrupts biofilm structures, while thermophilin 110 significantly reduces bacterial growth and viability. The preliminary trials indicate a dual-action approach offers a potential alternative to conventional treatments, enhancing food safety by effectively controlling Listeria biofilms in food processing environments. [ABSTRACT FROM AUTHOR]

Pleurotus ostreatus (oyster mushroom) holds excellent promise worldwide, bringing several opportunities and augmenting the tool sets used in the biotechnology field, the food industry, and medicine. Our study explores the antimicrobial and probiotic growth stimulation benefits of freeze-dried P. ostreatus powders (OMP-TF, oyster mushroom powder from the total fresh sample; OMP-CSR, oyster mushroom powder from the cooked solid residue; OMP-CL, oyster mushroom powder from the cooked liquid), focusing on their bioactive compounds and associated activities. Our research examined polysaccharide fractions—specifically total glucans and α- and β-glucans—alongside secondary metabolites, including polyphenols and flavonoids, from freeze-dried mushroom powders. Additionally, carbon nanodots (CNDs) were also characterized. The growth inhibition was tested against Escherichia coli and Staphylococcus epidermidis, while the capacity for stimulating probiotic growth was evaluated using Lactobacillus plantarum and Lactobacillus casei. Evidence indicates that OMP-CL and OMP-CSR exhibit significant antimicrobial properties against S. epidermidis Gram-positive bacteria. OMP-CL notably promoted the growth of L. casei. OMP-CL, containing the most significant number of CNDs, has shown to be a valuable source for gut microbiota modulation, with its antimicrobial and probiotic-stimulating efficacy. However, further in vitro and in vivo studies should be performed to explore CNDs and their behavior in different biological systems. [ABSTRACT FROM AUTHOR]

The rapid and reliable detection of pathogenic bacteria remains a significant challenge in clinical microbiology. Consequently, the demand for simple and rapid techniques, such as antimicrobial peptide (AMP)-based sensors, has recently increased as an alternative to traditional methods. Melittin, a broad-spectrum AMP, rapidly associates with the cell membranes of various gram-positive and gram-negative bacteria. It also inhibits bacterial biofilm formation in blood culture media. In our study, bacterial growth was measured using electrical vertical-capacitance sensors with interdigitated electrodes functionalized with melittin, a widely studied AMP. The melittin-immobilized vertical-capacitance sensors demonstrated real-time detection of both standard and clinically isolated bacteria in media. Furthermore, these sensors successfully detected clinically isolated bacteria in blood culture media while inhibiting bacterial biofilm formation. Melittin-immobilized vertical-capacitance sensors provide a rapid and sensitive pathogen detection platform, with significant potential for improving patient care. [ABSTRACT FROM AUTHOR]

Background Tigecycline is an antimicrobial agent with a broad spectrum of activity against both Gram-positive and Gram-negative bacteria. However, mobile tigecycline resistance gene clusters, such as tnfxB-tmexCD-toprJ , have spread globally. The prevalence of tigecycline-resistant Enterobacterales in clinical settings in Japan is unknown. Objectives To investigate the tnfxB-tmexCD-toprJ gene cluster in the genome sequences of Enterobacterales clinical isolates in Japan. Methods We investigated the tnfxB-tmexCD-toprJ cluster from the genome sequences of 5143 Enterobacterales isolates collected from 175 hospitals around Japan between 2019 and 2020 as part of a national genomic surveillance program for antimicrobial-resistant bacteria. Results The tnfxB1-tmexCD1-toprJ1 cluster was detected in two Klebsiella pneumoniae isolates in 2019. One isolate possessed a 299.4 kb IncFIB(K) plasmid, pJBBGAAF19431, and the other possessed a 224.9 kb IncHI1B/IncFIB(K) hybrid plasmid, pJBEAACG19501, co-carrying multiple antimicrobial resistance genes, including extended-spectrum β-lactamase genes, bla OXA-1 and bla CTX-M-27, respectively, along with tnfxB1-tmexCD1-toprJ1. The genetic context of the tnfxB1-tmexCD1-toprJ1 -surrounding structure on pJBBGAAF19431 was similar to that of a K. pneumoniae plasmid pHNAH8I-1 from a chicken in China in 2017, and the cluster was embedded in an apparently intact mobile DNA element: strand-biased circularizing integrative element. The tnfxB1-tmexCD1-toprJ1 on pJBEAACG19501 was embedded in a Tn 3 family transposon related to Tn As1. The plasmid pJBEAACG19501 was highly similar to that of K. pneumoniae , isolated from humans in China in 2021. Conclusions tmexCD-toprJ was present in Japan as of 2019. Even in Japan, where the clinical use of tigecycline is significantly rare, tmexCD-toprJ -harbouring multidrug-resistant Enterobacterales is a public health threat and requires continuous monitoring. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus, commonly referred to as S. aureus, is a type of bacteria that is often found on the skin and in the nasal passages of humans. Staphylococcus aureus is a common but potentially dangerous bacterium, notable for its role in various infections and its capacity for antibiotic resistance. In this situation, our motivation is to develop a photonic crystal fiber detector to detect these deadly gram-positive bacteria. In our study, we achieved a max Relative Sensitivity (RS) of 96.82% and 96.73% on the x and y poles, respectively, at an operating frequency equal to 3.2 THz. We further investigate several kinds of losses, such as loss of confinement (CL) and loss of effective material (EML). We achieve minimal CL that is 3.415 × 10–5 dB/m and 1.624 × 10–4 dB/m on the x and y poles, respectively. The lowest EMLs we achieve are 0.0062 cm−1, and 0.0085 cm−1 on the x and y poles, respectively. The small size and flexibility of the suggested PCF sensor make it suitable for miniaturized and portable sensing devices. This portability is advantageous for point-of-care diagnostics and field applications where rapid and on-site detection of Staphylococcus aureus is needed. [ABSTRACT FROM AUTHOR]

Thiazole derivatives (7a-f and 9a-i) were synthesized in good yields (up to 98%). The synthetic protocol is achieved through a two-step reaction. The synthesized candidates were then evaluated for their antimicrobial efficacies against gram-positive and gram-negative bacteria. 4-methyl-2-(2-(3-(pentyloxy)benzylidene)hydrazinyl)-5-(p-tolyldiazenyl)thiazole showed significant antimicrobial activity against Staphylococcus aureus (ATCC: 13565) compared to ampicillin. On the other hand, 2-(2-(3-(hexyloxy)benzylidene)hydrazinyl)-4-(4-methoxyphenyl)thiazole shows potent activity against Klebsiella pneumonia (ATCC: 10031) compared to gentamicin as a standard antibiotic. The ADME profile of the prepared compounds indicated favorable pharmacological behaviors. Additionally, docking and in-silico ADMET analyses were performed for the promising derivatives and the results revealed strong antimicrobial activity. DFT calculations were performed, which provided additional insight into the thiazoles' structure and formation. [ABSTRACT FROM AUTHOR]

In RP4 conjugation, approximately 350 bp of the origin of transfer (oriT) is required for transfer. Within this oriT , there are binding regions for the transfer-related proteins TraI, TraK, and TraJ. We investigated the influence of deleting each protein-binding region within oriT on transfer efficiency in Escherichia coli, Streptomyces lividans , and Bacillus subtilis. The deletion of the TraI-binding region completely abolished transfer in all species. The partial deletion of the TraK-binding region had a minimal impact when targeting but affected efficiency when targeting B. subtilis. The deletion of the TraJ-binding region completely abolished transfer in E. coli and B. subtilis but only reduced efficiency in S. lividans. This is the first report to investigate the influence of each region within oriT on transfer efficiency in S. lividans and B. subtilis , suggesting that the length of oriT required for effective RP4 conjugation varies when targeting Gram-positive bacteria. [ABSTRACT FROM AUTHOR]

This study aimed to reveal interactions of the stress response sigma subunits (factors) σD and σH of RNA polymerase and promoters in Gram-positive bacterium Corynebacterium glutamicum by combining wet-lab obtained data and in silico modeling. Computer modeling-guided point mutagenesis of C. glutamicum σH subunit led to the creation of a panel of σH variants. Their ability to initiate transcription from naturally occurring hybrid σD/σH-dependent promoter Pcg0441 and two control canonical promoters (σD-dependent PrsdA and σH-dependent PuvrD3) was measured and interpreted using molecular dynamics simulations of homology models of all complexes. The results led us to design the artificial hybrid promoter PD35H10 combining the −10 element of the PuvrD3 promoter and the −35 element of the PrsdA promoter. This artificial hybrid promoter PD35-rsdAH10-uvrD3 showed almost optimal properties needed for the bio-orthogonal transcription (not interfering with the native biological processes). [ABSTRACT FROM AUTHOR]

Background & Objective: Chronic suppurative otitis media is a fatal condition owing to its propensity for intracranial extension. The inadvertent use of antibiotics has led to resistance among causative organisms. The objectives of this study were to determine causative bacteria, their antibiotic resistance and susceptibility patterns, and their response to antibiotics after a one-month follow-up. Method: It was a prospective study conducted in the ENT department of Khyber Teaching Hospital, Peshawar from June 2023 to March 2024. Ear swabs were collected for microscopy and bacterial culture. Statistical analysis was done using IBM-SPSS-20, and GraphPad Prism. Results: Data was collected from 113 patients. The mean age of the patients was 22 + 2 years. Out of 113 samples, 97(85.5%) showed growth on culture whereas 16(14%) showed no growth, with 95 (98%) unimicrobial, while 2 (2%) showed polymicrobial growth. Pseudomonas aeruginosa was the commonest bacteria isolated 38(38%), followed by S. aureus, Proteus species, and S. saprophyticus. Gram-positive bacteria were susceptible to Linezolid (80%), followed by Vancomycin (76%), with resistance to Ciprofloxacin (75-84%), Ampicillin (70%), and Ceftriaxone (75-80%). Gramnegative bacteria showed susceptibility to carbapenem (50-100%) and Piperacillin/Tazobactam (50% to 93%), with resistance to Ciprofloxacin (50-87%), Ceftriaxone (87%), and Amoxicillin/Clavulanate (72-90%). After one month of follow-up, 82% of patients showed improvements, with noncompliance significantly associated with the persistence of symptoms (p<0.01). Conclusion: Moderate to high resistance against ciprofloxacin, third-generation cephalosporin, ampicillin, amoxicillin plus clavulanate, and clindamycin is an eye-opener. Our results underscore the critical need for judicious administration of empirical antibiotics. [ABSTRACT FROM AUTHOR]

An analysis was carried out to determine the antibiotics evaluation of bacterial isolates associated with Imo State University (IMSU) Microbiology laboratory and sub offices. Swab sticks used for streaking were inoculated unto a freshly prepared nutrient agar, MacConkey agar for bacteria. Identification of bacteria was performed by determining their gram staining properties, biochemical reactions and sugar tests indicating their presence. The microbial isolates obtained from this study were identified to belong to bacteria genus of Klebsiella sp., Escherichia coli, Bacillus sp., Streptococcus sp., Staphylococcus sp., Shigella sp., Micrococcus sp., and Pseudomonas sp. Klebsiella sp. had the highest percentage of occurrence (39.3%) while Pseudomonas sp had the least occurrence (1.8%). Bacteria isolates showed the highest percentage of susceptibility to Tarivid (OFX) 21(25%) followed by Augmentin (AU) 13(15.5%), Gentamycin (CN) 10(11.9%), Nalidixic (NA) 9(10.7%), Ceporex (CEP) 7(8.3%), Septrin (SXT) 4(4.8%), Ciprofloxacin (CPX) 3(3.6%) while the lowest percentage of susceptibility was to Streptomycin (S) 1(1.2%). The effectiveness of decontamination ranges from highlevel sterilization to simple cleaning with soap and water. Levels of decontamination include Sterilization, Disinfection, Antisepsis, and Cleaning. It is recommended that ethylene oxide gas is used in Sterilization of the air before any analysis is carried out. [ABSTRACT FROM AUTHOR]

Pulicaria species are used as herbal medicine and in the preparation of decoctions in several Asian and African regions. Among them, the plant Pulicaria burchardii is known for its medicinal properties, but comprehensive studies on its biological activity are still limited. This study examined the properties of the essential oil (EO) extracted by P. burchiardii and collected in Morocco during the flowering period. The focus was on its antimicrobial, anti-germinative, antioxidant, and antiviral activities, with the aim of evaluating its potential use in food preservation and beyond. The EO was subjected to various analyses to determine its chemical composition and biological efficacy. Specifically, GCMS and NMR analyses revealed that the EO is rich in oxygenated sesquiterpenes (72.59%), with 1-oxo-bisabolone being the predominant component (65.09%). The antimicrobial activity was tested against various Gram-positive and Gram-negative bacteria, demonstrating a significant inhibition of bacterial growth, particularly against Bacillus subtilis (MIC value of 0.6 mg/mL). The anti-germinative property was evaluated on spores of B. subtilis and other bacilli, such as Bacillus cereus, revealing a notable ability to prevent germination. For antiviral activity, the EO was tested against several pathogenic viruses including SARS-CoV-2 and HSV-1, showing an effective broad-spectrum reduction in viral replication in vitro. This study demonstrated that P. burchardii essential oil had excellent antibacterial and antiviral capabilities. The future challenge will focus mainly on the principal compound, 1-oxo-bisabolone, to demonstrate its real effectiveness as an antibacterial and/or antiviral. [ABSTRACT FROM AUTHOR]