Search Results (223)

Pseudomonas aeruginosa biofilm formation is critical to antibiotic resistance and persistence. Targeting cyclic di-GMP (c-di-GMP) signaling, a master biofilm formation and virulence regulator, presents a promising strategy to combat resistant bacterial infections. Myricetin, a natural polyphenolic flavonoid with documented antimicrobial and anti-biofilm activities, may enhance antibiotic efficacy against Pseudomonas aeruginosa. This study evaluated the synergistic effects of myricetin combined with azithromycin, ciprofloxacin, or cefdinir against both standard and drug-resistant Pseudomonas aeruginosa strains. Antibacterial activity, biofilm disruption, and motility inhibition were experimentally assessed, while molecular dynamic (MD) simulations elucidated myricetin’s molecular mechanism of action. Our results suggested that myricetin synergistically potentiated all three antibiotics, reducing c-di-GMP synthesis by 28% (azithromycin), 57% (ciprofloxacin), and 30% (cefdinir). It enhanced bactericidal effects, suppressed biofilm formation, and impaired swimming, swarming, and twitching motility. Computational analyses revealed that myricetin binds allosterically to FimX very well, a key regulator in the c-di-GMP signaling pathway. Hence, myricetin may act as a c-di-GMP inhibitor, reversing biofilm-mediated resistance in Pseudomonas aeruginosa and augmenting antibiotic efficacy. This integrated experimental and computational approach provides a framework for developing anti-virulence and antibiotic combination therapies against recalcitrant Gram-negative pathogens. Full article

Background/Objective: Non-typhoidal Salmonella is a leading cause of foodborne illness worldwide and presents a significant One Health concern due to zoonotic transmission. Although antibiotic therapy remains a standard approach for treating salmonellosis in severe cases in animals, the widespread misuse of antibiotics has contributed to the emergence of multidrug-resistant (MDR) Salmonella strains. This study provides insights into the genotypic and phenotypic characteristics among Salmonella isolates from necropsied cattle. Methods: A total of 1008 samples were collected from necropsied cattle. Salmonella enterica subspecies were identified by MALDI-TOF MS and subsequently confirmed by serotyping. The biofilm-forming ability of the isolated bacteria was assessed using a crystal violet assay. The motility of the isolates was assessed on soft agar plates. Additionally, the antimicrobial resistance genes (ARGs) and virulence genes were investigated. Antimicrobial resistance patterns were investigated against 19 antibiotics representing 9 different classes. Results:Salmonella species were isolated and identified in 27 necropsied cattle. Salmonella Dublin was the most prevalent serotype (29.6%). Additionally, all the isolates were biofilm producers at different levels of intensity, and 96.3% of the isolates exhibited both swarming and swimming motility. Furthermore, virulence genes, including invA, hilA, fimA, and csgA, were detected in all the isolates. The highest resistance was observed to macrolides (azithromycin and clindamycin) (100%), followed by imipenem (92.6%), and chloramphenicol (85.2%). All isolates were multidrug-resistant, with a multiple antibiotic resistance (MAR) index ranging between 0.32 and 0.74. The aminoglycoside resistance gene aac(6′)-Ib was detected in all the isolates (100%), whereas the distribution of other antimicrobial resistance genes (ARGs) varied among the isolates. Conclusions: The increasing prevalence of MDR Salmonella poses a significant public health risk. These resistant strains can reduce the effectiveness of standard treatments and elevate outbreak risks. Strengthening surveillance and regulating antibiotic use in livestock are essential to mitigating these threats. Full article

This study aimed to compare sperm parameters and reproductive outcomes after sperm selection using microfluidic chips versus conventional techniques (swim-up/density gradients). A systematic review and meta-analysis were performed after the extraction of relevant data from thirty-nine studies that met the inclusion criteria. Mean difference or odds ratio was calculated for each outcome. The analysis revealed that sperm selection using microfluidics yields lower sperm DNA fragmentation (MD = −9.98 [−13.19, −6.76], p < 0.00001), increased progressive motility (MD = 14.50 [7.84, 21.71], p = 0.04), total motility (MD = 10.68 [6.04, 15.31], p < 0.00001) and morphology (MD = 1.41 [0.67, 2.16], p = 0.0002). Significant differences were also found in the fertilization rate/MII oocyte microinjected (OR = 1.22 [1.01, 1.46], p = 0.04), implantation rate/embryo transfer (ET) (OR = 4.51 [1.42, 14.37], p = 0.01), clinical pregnancy/ET (OR = 1.73 [1.22, 2.45], p = 0.002), ongoing pregnancy/ET (OR = 1.99 [1.03, 3.83], p = 0.04), live birth rate/first cycle (OR = 1.59 [1.12, 2.24], p = 0.009) and per all embryo transfer (OR = 1.65 [1.06, 2.55], p = 0.03). No significant differences were found in embryo euploidy/number of biopsied blastocysts (OR = 1.34 [0.88, 2.04], p = 0.77), biochemical pregnancy/ET (OR = 1.23 [0.84, 1.80], p = 0.29), miscarriage rate/cycle (OR = 0.84 [0.54, 1.31], p = 0.35) and per pregnancy (OR = 0.71 [0.50, 1.02], p = 0.07), live birth rate/first embryo transfer (OR = 1.60 [0.80, 3.22], p = 0.18) and per concluded cycle (OR = 1.03 [0.53, 2.00], p = 0.92). To summarize, microfluidics may offer a beneficial approach in certain situations, particularly for patients with elevated sperm DNA fragmentation (SDF) levels. However, its integration into routine clinical practice cannot be justified yet in terms of cost-effectiveness. Additional research is needed to provide more comprehensive data on reproductive outcomes, especially live birth rates, which remain the ultimate goal of assisted reproductive technologies. Full article

With 80% of bacterial infections occurring as biofilms, biofilm-related infections have evolved into a critical public health concern. Probiotics such as Bacillus licheniformis have emerged as promising alternatives, offering new avenues for effective treatment. This study aimed to evaluate the activity of licheniformis against the growth, biofilm formation, motility, and quorum sensing (QS) of Salmonella typhimurium. Several experiments were conducted: The minimum inhibitory concentration (MIC) of Bacillus licheniformis against Salmonella typhimurium was determined to be 0.5 mg/mL using the broth microdilution method. The inhibition zone of 100 mg/mL of B. licheniformis against Salmonella typhimurium was 19.98 ± 1.38 mm; the time-growth curve showed that B. licheniformis can effectively inhibit the growth of Salmonella typhimurium. In biofilm experiments, at the MIC of B. licheniformis, the inhibition rate of immature biofilm of Salmonella typhimurium was 86.9%, and it significantly reduced the production of biofilm components (EPS, e-DNA, and extracellular proteases) (p < 0.05). The disruption rate of mature biofilm by B. licheniformis at the MIC was 66.89%, and it significantly decreased the levels of biofilm components (EPS and e-DNA) (p < 0.5). Microscopic observation showed that both the MIC and 1/2 MIC of B. licheniformis could reduce the number of bacteria in the Salmonella typhimurium biofilm, which was not conducive to the formation and maintenance of the biofilm structure. Swimming/Swarming assays and QS experiments confirmed that B. licheniformis inhibits the motility of Salmonella typhimurium and the secretion of AI-1-type quorum sensing molecules and downregulates the AI-2 quorum sensing system by upregulating lsr gene expression. These findings suggest that B. licheniformis could be a potential antimicrobial agent and biofilm inhibitor. Full article

Background/Objectives: The present study was aimed at documenting S. maltophilia occurrence in dogs with skin ailments, investigating its virulence, biofilm-forming ability, antimicrobial susceptibility, and zoonotic potential to inform preventive and therapeutic strategies against multidrug resistant S. maltophilia infections. Methods: Skin swabs (n = 300) were collected from dogs with dermatological ailments. Isolation was performed using selective media and confirmed with molecular methods, validated by MALDI Biotyper. Antimicrobial susceptibility testing and efflux activity assessment were conducted. Resistance genes related to sulfonamides, quinolones, and β-lactams were screened. Virulence was assessed by biofilm formation, motility, and virulence gene profiling. Results: In total, 15 S. maltophilia (5%) isolates were identified. All 15 isolates were susceptible to trimethoprim-sulfamethoxazole, enrofloxacin, gatifloxacin, levofloxacin, minocycline, and tigecycline, but resistant to cefpodoxime and aztreonam. The following resistance genes qnr (93.3%), bla_OXA-48 (46.7%), bla_KPC (33.3%), bla_NDM (33.3%), bla_CTX-M (20%), bla_SHV (20%), and bla_TEM (6.7%) were detected. All 15 isolates displayed high efflux activity. Overall, 9 isolates (60%) were strong biofilm producers, and 6 (40%) were moderate. Virulence genes such as virB, motA, rmlA, and fliC were present in all 15 isolates, with others varying in frequency. All isolates exhibited swimming motility. Heat map clustering showed diverse profiles, with no identical isolate patterns. Correlation analysis indicated positive associations between several antimicrobial resistance and virulence genes. Conclusions: This study underscores the zoonotic potential of S. maltophilia from dogs, advocating for a One Health approach to mitigate infection risks and limit the spread of virulent multidrug resistant pathogens. Full article

The quorum-quenching activity of essential oils (EOs) from Corsican aromatic plants was evaluated using the marine bacterium Aliivibrio fischeri as a model system. Among the eleven EOs screened, Myrtus communis EO showed significant interference with QS-regulated phenotypes (swimming motility, bioluminescence, and biofilm formation). Its activity was compared to Origanum vulgaris EO, known for its high carvacrol content and potent QS inhibition. The fractionation of M. communis EO revealed that its most polar fractions exhibited comparable levels of QS-disrupting activity. These chromatographic fractions significantly affected QS-controlled traits, indicating that minor or less volatile compounds may contribute to, or enhance, the overall bioactivity. Furthermore, M. communis EO and its polar fractions displayed stronger anti-QS effects against A. fischeri than O. vulgaris EO. These results highlight M. communis EO as a promising source of natural QS inhibitors and underscore the importance of exploring both complete EOs and their active fractions. This study supports the valorization of Mediterranean endemic flora as a reservoir of bioactive compounds, tested on a model system A. fischeri, and encourages future research on the potential of Myrtus communis against clinical bacterial isolates and the development of novel anti-virulence strategies. Full article

Sperm cryopreservation and assisted reproduction are powerful tools for the conservation of endangered species. The domestic cat has been a useful model for studying wild felid reproductive biology due to the limited availability of endangered individuals for experimental research. Here, we investigate the effect of cryodiluents (TEST vs. Biladyl) and the timing of glycerol addition (before vs. after refrigeration, in one vs. three steps, respectively) on post-thaw sperm quality (motility, acrosome integrity) and their subsequent in vitro fertilization (IVF) ability with homologous oocytes. The results showed no statistically significant differences in sperm traits when samples were cryopreserved in TEST or Biladyl, or when glycerol was added in one or three steps. Motile sperm and intact acrosomes were significantly correlated before and after cryopreservation, indicating consistent relationships in fresh and thawed samples. The use of Biladyl significantly reduced IVF rates after cryopreservation compared to fresh sperm. Cryopreservation in TEST led to IVF rates that were not significantly different from those of fresh sperm. Using swim-up after thawing, or adding 1 mM pentoxifylline, did not enhance IVF results. Overall, a TEST cryodiluent with 4% glycerol added in one step is a reliable option for preserving epididymal cat spermatozoa. Full article

The use of microfluidic sperm sorting (MFSS) systems in infertility treatment is increasing due to their practicality and ease of use. While often presented as highly effective, their efficacy in patients with varying sperm analysis results remains uncertain. In this study, we evaluated the effectiveness of MFSS compared with the swim-up (SU) technique in terms of oxygen radical levels and spermiogram parameters. Samples from each patient were processed using both methods, followed by assessments of sperm concentration, motility, morphology, DNA integrity, acrosomal status, and mitochondrial membrane potential. Participants were selected based on sperm analysis and categorized as normozoospermic (n = 40) or non-normozoospermic (n = 28). An analysis of separation techniques revealed no significant differences, except for a lower percentage of DNA-fragmented sperm in the MFSS group compared with SU within the non-normozoospermic cohort (SU: 10.0% vs. MFSS: 5.69%, p = 0.027). No differences were observed between SU and MFSS in normozoospermic men. The MFSS method is a simple technique, frequently used in laboratories, that yields good results but does not offer a substantial advantage over SU. The primary benefit of MFSS appears to be a significant reduction in the proportion of sperm with DNA fragmentation compared with SU in patients with abnormal sperm analysis results. Full article

Listeria monocytogenes is of a significant concern for the food industry, largely due to its ability to form biofilms. Flagellar motility and environmental factors are crucial for biofilm formation. Cysteine is an important compound affecting the behavior of this bacterium; therefore, we investigated its role in growth, biofilm formation and motility of L. monocytogenes 10403S through a mutant in cysteine uptake (ΔctaP). Basal defined media (DM) and L-cysteine-supplemented DM were used. Biofilm formation was promoted by L-cysteine supplementation in both wild type (WT) and ΔctaP. Lower biofilm formation of ΔctaP compared to WT indicates the significance of the cysteine transporter and cysteine uptake. A negative correlation was found between growth and biofilm formation, especially in the presence of high L-cysteine concentrations. Motility experiments showed that as the L-cysteine concentration increased, the swarming motility of WT decreased. Furthermore, swimming motility of WT was enhanced with L-cysteine supplementation, while the swimming motility of ΔctaP remained unaffected. To evaluate the role of cysteine and CtaP in biofilm formation and motility, transcriptome analysis, comparing WT and ΔctaP in basal and L-cysteine-supplemented (1.57 and 3.67 mM) DM, was conducted at 37 °C. The investigation of biofilm-related genes explained the role of ctaP and revealed induced expression of flagella and chemotaxis genes by L-cysteine. Full article

Sperm preparation is a critical step in assisted reproduction, aiming to isolate spermatozoa with optimal characteristics and high fertilizing potential. Traditional sperm selection methods involve centrifugation, which may cause sperm damage. Microfluidic sperm sorting (MSS) offers an alternative approach, mimicking the female reproductive tract environment, avoiding centrifugation, and reducing manipulation and processing time. This study aims to compare the performance of MSS and Swim-up (SU) in 26 normozoospermic, 31 hyperviscous normozoospermic, 15 oligozoospermic, and 9 asthenozoospermic subjects. Semen samples were collected from male subjects undergoing routine semen analysis at Careggi University Hospital, Florence. Sperm selection was carried out using both SU and MSS. The parameters assessed included sperm motility, viability, concentration, kinematics, DNA fragmentation (sDF), chromatin compaction, and oxidative status. Both SU and MSS improved sperm characteristics compared to unselected samples. MSS isolated high-quality spermatozoa with lower sDF and higher chromatin compaction than SU, not only in normozoospermic samples but also in samples with semen defects like hyperviscosity, low concentration and/or motility, and high sDF. In conclusion, the use of microfluidics may enhance the chances of successful fertilization and improve reproductive outcomes, especially for individuals with compromised semen quality where conventional methods may fail. Full article

Litsea cubeba essential oil (LCEO) has been reported as an antibacterial agent, but its effects against Salmonella typhimurium (S.Tm) and the underlying mechanisms remain unclear. The antibacterial efficacy of LCEO was assessed utilizing both microdilution and growth curve methodologies, and its chemical composition was thoroughly analyzed. Morphological alterations in the cells were observed through scanning electron microscopy (SEM), while cellular permeability was gauged based on the variations in nucleic acid and protein contents. The impact of LCEO on ATPase activity and its anti-biofilm formation activity was assessed using colorimetric methods. The results indicated that the MIC and MBC of LCEO against S.Tm were 0.4 mg/mL and 0.8 mg/mL, respectively. SEM and PI staining revealed disrupted bacterial cell integrity. Compared to those in the control group, treatment with LCEO significantly elevated the levels of extracellular nucleic acids and proteins (p < 0.05). Furthermore, at the MIC, LCEO led to a 77.9% reduction in AKP content, and decreased intracellular Na⁺K⁺-ATPase and Ca²⁺Mg²⁺-ATPase activities by 79.9% and 54.6%, respectively. Additionally, LCEO markedly inhibited biofilm formation, enhanced surface hydrophobicity, and diminished the swimming motility of S.Tm. Overall, LCEO exhibited promising antibacterial properties, indicating its potential as an effective inhibitor against S.Tm. Full article

Spermatozoa were isolated from the seminal fluid using washing (wash), post-capacitation (POS), and swim-up (SU) techniques, followed by analysis through Surface-Enhanced Raman Spectroscopy (SERS). Density gradient and swim-up methods were applied to 35 semen samples to validate sperm quality. The resulting spectra showed notable variations at 408 cm⁻¹ (S–S stretch attributed to lysozyme) and 728 cm⁻¹ (associated with DNA alterations and methylation). These spectral markers were incorporated into partial least squares discriminant analysis (PLS-DA) models to distinguish among sperm populations prepared by different methods. One PLS-DA model differentiated wash from POS and SU, attaining 86% sensitivity and 91% accuracy. Another model distinguished between POS and SU, achieving 77% sensitivity and 74% accuracy. The combined use of SERS and multivariate analysis offers a promising alternative for assessing sperm quality, supported by motility assessments in 35 validated samples. This approach could enhance both the accuracy and efficiency of reproductive diagnostics. Full article

Type IV pili (T4P) machinery is critical for bacterial surface motility, protein secretion, and DNA uptake. This review highlights the ecological significance of T4P-dependent motility in Thermus thermophilus, a thermophilic bacterium isolated from hot springs. Unlike swimming motility, the T4P machinery enables bacteria to move over two-dimensional surfaces through repeated cycles of extension and retraction of pilus filaments. Notably, T. thermophilus exhibits upstream-directed migration under shear stress, known as rheotaxis, which appears to represent an adaptive strategy unique to thermophilic bacteria thriving in rapid water flows. Furthermore, T4P contributes to the capture of DNA and phages, indicating their multifunctionality in natural environments. Understanding the T4P dynamics provides insights into bacterial survival and evolution in extreme habitats. Full article

The bacterial flagellum, a complex nanomachine composed of numerous proteins, is utilized by bacteria for swimming in various environments and plays a crucial role in their survival and infection. The flagellar motor is composed of a rotor and stator complexes, with each stator unit functioning as an ion channel that converts flow from outside of cell membrane into rotational motion. Paenibacillus sp. TCA20 was discovered in a hot spring, and a structural analysis was conducted on the stator complex using cryo-electron microscopy to elucidate its function. Two of the three structures (Classes 1 and 3) were found to have structural properties typical for other stator complexes. In contrast, in Class 2 structures, the pentamer ring of the A subunits forms a C-shape, with lauryl maltose neopentyl glycol (LMNG) bound to the periplasmic side of the interface between the A and B subunits. This interface is conserved in all stator complexes, suggesting that hydrophobic ligands and lipids can bind to this interface, a feature that could potentially be utilized in the development of novel antibiotics aimed at regulating cell motility and infection. Full article

Background: Flowering members of the globally diffused Rosaceae family include popular plants, such as apple, almond, and cherry, which play a fundamental role as honeybee nectariferous and polleniferous agents. Through the production of honey, these plants can also play an indirect role in the prevention and treatment of many diseases, including infections, fighting the occurrence of resistant microorganisms, and concurrently stimulating the growth of beneficial bacteria. Objectives: This study focused on the effect of some Rosaceae plants’ honey, including hawthorn, cherry, raspberry, almond, and apple, against the pathogens Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus. Results: Results demonstrated the honey’s ability to impair swimming motility. A crystal violet test indicated that honey could inhibit the formation and stabilization of biofilms, with inhibition rates up to 59.43% for immature biofilms (showed by apple honey against A. baumannii) and 39.95% for sessile bacterial cells in mature biofilms (when we used cherry honey against S. aureus). In the test with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cherry and apple honey were the most effective in inhibiting sessile cell metabolism honey in both immature (56.47% cherry honey vs. K. pneumoniae) and mature biofilms (54.36% apple honey vs. A. baumannii). Honey stimulated the growth of Lactobacillus bulgaricus, Lacticaseibacillus casei Shirota, Lactobacillus gasseri, Lacticaseibacillus plantarum, and Lacticaseibacillus rhamnosus; hawthorn, raspberry, and almond honey significantly increased the in vitro adhesion capacity of L. bulgaricus and L. casei Shirota. Tests with probiotic supernatants demonstrated honey’s ability to inhibit the biofilm formation and metabolism of the pathogens. Conclusions: Our results encourage further studies to assess the potential application of Rosaceae honey for food preservation and in the health field, as it could fight the antimicrobial resistance of food and clinical pathogens, and potentially enhance the host’s gut wellness. The use of honey for nanotechnological and biotechnological approaches could be suggested too. Full article