Search Results (10,997)

The rise in antimicrobial resistance represents a significant challenge to global health. The reason partially lies in an inappropriate use of conventional antibiotics and the subsequent rapid spread of multidrug-resistant pathogen strains. This emergency requires an urgent search for conceptually new antimicrobial agents. A viable alternative to conventional antibiotics is antimicrobial peptides (AMPs), which are ribosomally synthesized molecules with considerable potential as next-generation anti-infectious therapeutics. Previously, we have reported on the β-hairpin peptide Ap9, an analog of abarenicin from the marine polychaeta Abarenicola pacifica, with potent activity against key Gram-negative pathogens. Here, it is shown that Ap9 acts in a manner resembling polymyxin B, namely via interaction with lipopolysaccharide (LPS), and retains its activity against polymyxin-resistant isolates without observed cross-resistance, and causes insignificant damage in cytoplasmic membrane at bactericidal concentrations. NMR spectroscopy reveals that LPS binding induces a conformational rearrangement of Ap9, its dimer formation, and local structural remodeling of the peptide region (residues 8–12) into 3₁₀-helix. Bacterial resistance to Ap9 was found to be relatively low with a reduced susceptibility associated with infrequent genetic alterations, such as the mutation in lptD or the deletion in mlaA. Furthermore, Ap9 demonstrates a favorable tolerability, a wider therapeutic window than that of polymyxin B, and a sufficiently long half-life through the systemic use, as well as in vivo efficacy in murine models of Gram-negative infections, including sepsis caused by the mcr-1-harboring Escherichia coli strain. The obtained results point to Ap9 as a promising candidate for further preclinical studies aimed at development of an alternative to polymyxins. Full article

Vegetatively propagated crops, including cassava, sweet potato, banana, and potato, are susceptible to mixed-pathogen infections resulting from the continuous use of clonal planting material and infrequent seed replacement. A diverse array of viruses, bacteria, and fungi can accumulate within these materials over successive cultivation cycles, precipitating seed degeneration and complex disease syndromes that complicate diagnosis and management. Mixed infections frequently trigger synergistic interactions that exacerbate disease severity and yield losses. This review synthesizes data on mixed-pathogen complexes in vegetatively propagated crops, with particular focus on vascular and systemically colonizing pathogens and analyzing starch crops to highlight the epidemiological, biological, and ecological drivers of synergism and antagonism. Furthermore, the review examines host defense responses during coinfection, including the modulation of plant immune pathways, and evaluates how interpathogen dynamics influence pathological outcomes. Although advancements in molecular diagnostics—notably next-generation sequencing and metagenomics—have revolutionized the detection of mixed infections, they have also introduced challenges in differentiating causal agents from commensal microorganisms. Finally, we discuss the implications for integrated disease management, emphasizing clean seed systems, resistance breeding, and phenotyping strategies tailored to multipathogen environments. The dynamics of mixed infections is critical for resilient and sustainable management strategies amidst increasingly complex agricultural and climatic shifts. Full article

Arsenic-contaminated groundwater is a major environmental concern, particularly in northern Argentina. Here, Microbacterium oxydans AE038-20, isolated from arsenic-rich groundwater, was investigated to elucidate its tolerance and transformation capacity. Growth assays showed that the strain tolerates inorganic arsenic [As(III), As(V)] and methylarsenite [MAs(III)] without significant inhibition. Speciation analyses revealed progressive oxidation of As(III) to As(V), reaching near-complete conversion after 10 days. Similarly, MAs(III) was fully oxidized to MAs(V). Genome sequencing identified ars-related determinants, including arsR, arsC, putative arsenite efflux systems, and arsP, supporting detoxification via arsenate reduction and arsenite efflux. Proteomic analyses confirmed the expression of proteins related to arsenic resistance, oxidative stress response, and metal transport. However, no canonical arsenite oxidases were detected at either the genomic or proteomic level. Despite this, M. oxydans AE038-20 exhibited clear arsenic oxidation activity. The detection of pigment-associated proteins and in vitro oxidation assays suggest an alternative mechanism potentially mediated by redox-active pigments. These findings highlight an alternative pathway for arsenic transformation in environmental bacteria. Full article

Fermented dairy products with probiotic and functional properties are a promising matrix for modulation of the human microbiome. The functionality of such products will depend not only on the technological properties of the lactic acid bacteria included in the starter culture but also on the combined effects of metabolites, enzymatic activity, stress tolerance, and strain-specific adaptation mechanisms. The aim of this work was to conduct a comprehensive analysis of Lactobacillus strains to facilitate the design of microbial consortia for the development of fermented products with diverse functional properties. Twenty Lactobacillus strains from different species were investigated using microbiological, physicochemical, and biochemical methods to evaluate antagonistic activity against opportunistic microorganisms and to assess changes in amino acid and organic acid profiles, vitamin content, fatty acid composition, and enzymatic activity. Additionally, proteomic analysis was performed to create a matrix of functional complementarity of the studied strains, representing proteins associated with antimicrobial activity, bacteriocin transport, resistance to oxidative stress, surface structure formation, and adhesion. It was shown that the studied strains exhibit pronounced functional heterogeneity, demonstrating the feasibility of scientifically based selection of strains to create next-generation fermented dairy products with predictable properties. Full article

Background/Objectives: Multidrug-resistant (MDR) Gram-negative bacteria represent a significant public health concern worldwide, particularly in resource-limited settings. In Ghana’s Tamale Metropolis, limited data exist on the prevalence and trends of MDR bacteria, posing challenges to effective antimicrobial stewardship. Methods: This study analyzed microbiological data from 2020 to 2023 to address these knowledge gaps. Results: Among the 4859 clinical samples analyzed, 1570 (33.7%) yielded Gram-negative bacterial isolates, with an MDR prevalence of 40.6%. The most frequently isolated organisms were Klebsiella spp. (28.9%) and Escherichia coli (20.4%). Resistance to cephalosporins (51%) and ciprofloxacin (46%) was particularly pronounced, highlighting the diminishing efficacy of commonly used antibiotics. Older adults (aged 60 years and above) presented the highest MDR prevalence, reflecting the vulnerability of this demographic group. Conclusion:These findings underscore the urgent need for enhanced antimicrobial stewardship programs, improved infection prevention and control measures, and continuous resistance monitoring to combat the growing threat of MDR bacteria in the region. Strengthening laboratory capacity and adherence to strict antibiotic usage policies are crucial for reducing the burden of MDR infections and improving patient outcomes. Full article

Water kefir production requires the fermentation of sweetened water with polysaccharide starter culture embedded with bacteria and yeast, which determines the finished product’s sensory, microbial, and chemical profile. The culture self-propagates, producing a new culture biomass used to inoculate subsequent raw materials. This study evaluated the effect of sequential culture transfers (across batches) and prolonged storage (within batches) on the microbial and chemical composition of finished beverages. Six commercial cultures were used in 20 sequential fermentations. The beverages were analyzed immediately after fermentation and then were stored at 4 °C for analysis every 2 weeks for 12 weeks. Microbial populations, including aerobic plate count (APC), lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast, were enumerated; major organic acids, sugars, and alcohols were quantified chromatographically. Sequential culture transfers and storage resulted in minimal microbial and chemical component changes. The initial microbial counts were similar across brewing cycles and culture systems with high counts of LAB. The culture transfers resulted in a decrease in initial ethanol levels to a negligible level. Microbial viability and sucrose content decreased with prolonged beverage storage. Overall, this study revealed that water kefir cultures were resistant to temporal changes and beverages’ microbial and chemical constituents were statistically stable (p > 0.05) during refrigeration. Full article

The rapid emergence of multi-drug resistant (MDR) bacteria has become a major health concern, driving the need to identify new antimicrobial resources. Recently, endophytes, inhabiting in internal tissues of medicinal plants, have drew important interest from the scientific community, as reservoirs of bioactive metabolites. Numerous studies highlight the symbiotic relationship between plants and their endophytes, in which these microorganisms produce antimicrobial compounds, helping the host plant’s defense against pathogens. Plantago major (commonly known as plantain) is widely recognized for its therapeutic properties, especially for its antimicrobial properties. In this study, endophytic fungi were isolated from Plantago major, morphologically characterized and identified using ITS sequencing. Their antibacterial activity was assessed using the agar diffusion assay. In total, 21 endophytic fungal isolates were obtained from different plant tissues, including leaves, stems, roots, and flowers. Antibacterial assays against methicillin-resistant Staphylococcus aureus (MRSA) were investigated on PDA, SDA, and CDA media. Amongst the isolates, nine strains (MD-H1, MD-L1, MD-L2, MD-L3, MD-L4, MD-L5, MD-R1, MD-T1, MD-T2, and MD-T10) showed medium to strong antibacterial effects, with inhibition zones exceeding 15 mm. The result suggests that endophytic fungi associated with Plantago is a valuable source of anti-MRSA compounds. Further work will focus on identifying the secondary metabolites responsible for this activity and elucidating their chemical structures, providing a basis for the development of new potent antibiotic agents. Full article

Neonatal infections remain a leading cause of morbidity and mortality worldwide, particularly among preterm and low-birth-weight infants and in low- and middle-income countries. This burden has intensified with the global increase in multidrug-resistant (MDR) bacteria, especially in neonatal intensive care units, where prolonged hospitalization, invasive interventions, and exposure to broad-spectrum antibiotics promote colonization, transmission, and invasive infection. In this narrative review, we explore the epidemiology and microbiological characteristics of MDR bacterial infections in newborns, alongside their associated risk factors, diagnostic challenges, treatment outcomes, and prevention strategies. Across different settings, Gram-negative pathogens, particularly Klebsiella pneumoniae, Escherichia coli, and Acinetobacter baumannii, account for a substantial proportion of severe neonatal infections, whereas methicillin-resistant Staphylococcus aureus remains important in selected units. The risk of MDR infection is driven by a complex interplay of factors, ranging from maternal and perinatal exposures to the inherent immunological vulnerability of newborns, hospital-based transmission, antibiotic selection pressure, and structural deficiencies in healthcare infrastructure. Diagnosis remains challenging because clinical presentations are nonspecific and culture-based methods are constrained by low blood volumes, prior antimicrobial exposure, and delayed turnaround times. Treatment is increasingly complicated due to resistance to standard empirical regimens, substantial regional variation in susceptibility profiles, and limited neonatal pharmacokinetic and safety data for reserve agents. Current evidence mainly supports surveillance-informed empirical therapy, susceptibility-guided treatment adjustment, antimicrobial stewardship, and strict infection prevention measures. Future progress will require neonatal-specific clinical trials, harmonized surveillance systems, stronger molecular epidemiology, and more equitable access to microbiological diagnostics and effective treatment. Full article

Background/Objectives: Due to the widespread problem of antimicrobial resistance (AMR), there is an urgent need to identify new antibacterial targets that act through mechanisms distinct from those of existing antibiotics. One of these targets is the essential cell division protein FtsQ, which is a central hub of the Gram-negative divisome, but the druggability of its extensive protein–protein interaction (PPI) interfaces remains poorly defined. Here, we present a comprehensive structure-based in silico characterization of Escherichia coli FtsQ aimed at identifying and prioritizing druggable regions for PPI modulation. Methods: We analyzed E. coli FtsQ in both apo and complexed states (FtsQB, FtsQL, and FtsQBL) using a combination of pocket-mapping tools (FTMap and SiteMap), evolutionary conservation analysis (ConSurf), and structure property assessment (BLAST, ProBiS) to map and evaluate potential binding pockets of FtsQ protein. Results: Eight potential binding sites were predicted across the β and POTRA domains of FtsQ. One previously unreported site within the POTRA domain was prioritized as a candidate site, characterized by favorable druggability scores, strong evolutionary conservation, and a putative role in the FtsQ–FtsW/FtsN/FtsI interaction network. In contrast, two highly conserved sites at the FtsQ–FtsB/FtsL interaction interface were structurally flat, indicating limited suitability for classical small-molecule binding and greater compatibility with alternative modalities such as macrocycles or peptidomimetics. Conclusions: Although FtsQ lacks deep canonical binding pockets, this study proposes several conserved and potentially tractable regions as candidate sites, supporting its potential as a non-classical but promising antibacterial target for disrupting bacterial cytokinesis. Full article

Background/Objectives: Surveillance studies focusing on clinically relevant infections confirm that antimicrobial resistance (AMR) is widespread among bacterial isolates from European households and livestock domestic animals. Due to the shared interface between humans and these animals, as well as an increasing trend in the number of pets per person, the spread of AMR is of concern. Methods: In this study, antibiogram reports issued at the bacteriology laboratory of the Department of Veterinary Medicine of the University of Bari from 2020 to 2025 were reviewed and analyzed using descriptive and statistical methods to explore the AMR patterns. Results: Two hundred and twenty-eight results were included, comprising 2599 individual tests. A total of 76 molecules across 25 antibiotic classes were tested. Ear swabs were the most common sample type, and Staphylococcus spp. and E. coli were the most isolated bacteria. Two-thirds of the isolates were susceptible to at least one substance classified by the European Medicine Agency (EMA) as category D. Fairly low non-susceptibility (NS) results were obtained for sulfamethoxazole-trimethoprim (D category), gentamicin (C category), and enrofloxacin (B category). Conclusions: An increase in the NS trend was observed over the five-year period. Overall, the results support the need for continuous antibiotic stewardship. Full article

This study evaluated the effects of a commercially produced, ready-to-use probiotic supplement, dominated by lactic acid bacteria, on the growth performance and selected health indicators of salmon (Salmo salar L.) fry, parr, and presmolts reared for restocking purposes. The results indicated a stage-specific response to probiotic application. In salmon fry, short-term immersion baths were associated with reduced juvenile mortality and improved tolerance to fluctuations in temperature and dissolved oxygen. In parr, immersion treatments were linked to improved growth performance, condition factor, and a lower incidence of gill-cover necrosis compared to the Control group. In presmolts, short-term dietary supplementation with probiotics was associated with increased growth rates relative to Controls. Probiotic application was associated with changes in bacterial isolates and, in some groups, lower antimicrobial resistance (AMR) indices, particularly after 14 days of immersion treatment. Probiotic supplementation was associated with improved growth and increased tolerance to environmental stressors, indicating its potential to support fish welfare and sustainable aquaculture. Full article

Background/Objectives: Integrons are genetic platforms that allow bacteria to acquire antimicrobial resistance (AMR) genes, making them a focal point for many AMR studies and surveillance programs. This study investigated how the prevalence of integrons (intI and attI genes) in third-generation cephalosporin-resistant E. coli (3GCR-Ec) varied across three different sources (i.e., healthy children, domestic animals and urinary tract infections). The study aimed to determine how different classes of AMR genes vary among 3GCR-Ec with integrons present versus those where integrons are absent. Methods: We analyzed 3GCR-Ec isolates collected from semirural parishes of Eastern Quito, Ecuador, that included: (1) 3GCR-Ec from healthy children (n = 946), (2) 3GCR-Ec from domestic animal species (n = 673), and 3GCR-Ec from patients with urinary tract infections (UTIs) (n = 138). Genomic analyses were performed for all 1757 sequences to determine how the presence and absence of integrons was associated with AMR gene carriage. Results: Among the total sequences of 3GCR-Ec evaluated across all datasets, nearly one-third (31%) were integron-negative. 3GCR-Ec from UTI patients, however, had a higher percentage containing integrons (79%). Across all sets of 3GCR-EC, integron-positive isolates carried an average of 10.3 (±3.0 SD) AMR genes versus 4.8 (±2.5 SD) AMR genes in integron-negative isolates. This study found that between 21% to 33% of 3GCR-Ec across the three different sources lacked integrons but maintained the ability to carry diverse classes of AMR genes, including beta-lactams, aminoglycosides, tetracyclines, and multidrug resistance mechanisms (e.g., general-purpose efflux pumps). Conclusions: While integrons were associated with greater AMR genes on average, the study highlights that solely relying on integrons for tracking drug-resistant bacteria misses a substantive portion of AMR that is present in integron-negative strains. Full article

Background and Objectives: The epidemiological characteristics of Candida species have changed worldwide, with an increasing number of reports on co-infections with non-albicans Candida species (NACs) and multidrug-resistant bacteria. A longer length of hospital stay, more severely ill patients, and empirical antimicrobial use in intensive care units (ICUs) increased the prevalence of Candida healthcare-associated infections (HAIs). If the diagnosis or treatment of invasive candidiasis is delayed, the morbidity and mortality of patients will significantly increase. Materials and Methods: We conducted a nationwide surveillance study to analyze data on HAIs in the ICUs of medical centers and regional hospitals between 2018 and 2023. We assessed the temporal trends of Candida species (including Candida albicans and NACs) across all HAIs, bloodstream infections (BSIs), and urinary tract infections (UTIs), and simultaneously assessed the corresponding trends of Enterococcus faecium (Efm). A linear trend for the proportions of microorganisms from 2018 to 2023 was noted according to the Mantel–Haenszel chi-square test. Spearman’s rank correlation coefficients were used to analyze the correlations between pathogen proportions, systemic antimicrobial agent consumption, and length of ICU stay. Results: The overall proportion of all Candida species in HAIs in the ICUs increased significantly from 15.13% to 16.74% (p < 0.001); this increase was driven mainly by NACs (increasing from 6.84% to 7.91%, p < 0.001) from 2018 to 2023. The proportion of Efm increased significantly, from 7.7% to 11.11% (p < 0.001). The proportions of all Candida species significantly increased in UTIs (from 24.63% to 28.13%, p < 0.001), especially NACs, while the proportion of Efm also increased significantly in UTIs (from 9.47% to 15.32%, p < 0.001). With respect to the UTIs, the proportion of all the Candida species, C.albicans, and NACs were positively correlated with the amount of systemic antibiotics used. A longer hospital stay was strongly correlated with all Candida HAIs and UTIs, especially NACs. Significantly ecological associations between all the Candida strains and Efm were observed for UTIs. Conclusions: This study revealed that a persistent expansion of NAC infections was associated with increased Efm infections and rising antibiotic consumption. The changes in the proportions of different Candida species in UTIs were most pronounced. These findings support an ecological model in which antibiotic stress and chronic critical illness contribute to the expansion of fungal–bacterial co-infections in the ICU setting and underscore the need for integrated antibiotic management and multi-infection surveillance. Full article

Cancer remains one of the leading causes of morbidity and mortality worldwide, and despite major advances in surgery, chemotherapy, radiotherapy, and immunotherapy, important therapeutic limitations persist, including systemic toxicity, therapeutic resistance, and poor drug penetration into hypoxic tumor regions. These challenges have renewed interest in alternative biological strategies, particularly the use of bacteria and bacterial toxins as antitumor agents. Certain bacterial species possess intrinsic tumor-targeting properties, including the ability to selectively colonize hypoxic and necrotic regions of solid tumors that are poorly accessible to conventional therapies. This review provides a comprehensive analysis of the mechanisms underlying bacteria-mediated anticancer activity, including selective tumor colonization, direct oncolysis, immune activation, and toxin-mediated cytotoxicity. Both obligate anaerobes (e.g., Clostridium and Bifidobacterium) and facultative anaerobes (e.g., Salmonella, Escherichia coli, and Listeria monocytogenes) are examined for their tumor-targeting potential. In addition, we discuss the oncological applications of several bacterial toxins and toxin-derived therapeutic constructs, including Cytolysin A (ClyA), Clostridium difficile toxin B (TcdB), diphtheria toxin, Pseudomonas aeruginosa exotoxin A, and Clostridium perfringens enterotoxin (CPE). Emerging strategies such as recombinant immunotoxins and bacterial-directed enzyme prodrug therapy (BDEPT) are also reviewed. Finally, current translational challenges, including pharmacokinetic limitations, immune clearance, and biosafety considerations, are analyzed, highlighting future directions for integrating bacteria-based platforms into next-generation cancer therapies. This approach reflects the growing interest in microbial strategies for oncology and underscores the potential of bacteria and their toxins as innovative tools in the development of targeted anticancer therapies. Full article

Rhizoctonia solani is the main pathogen that causes tomato root rot, which is a soilborne disease that seriously affects tomato production, leading to huge economic losses. Biocontrol is an excellent control method for suppressing plant disease, as it is environmentally friendly, safe, and sustainable. Currently, reviews of the biocontrol of tomato root rot caused by R. solani are scarce. In this review, biocontrol agents, including bacteria and fungi, that can control tomato root rot caused by R. solani are discussed in depth, as well as their control effects. Moreover, this review systematically analyzes the potential control mechanisms of biocontrol agents, including the production of cell-wall-degrading enzymes, the production of metabolites, mycoparasitism, the induction of plant systemic resistance, and competition. Considerations for the practical application of biocontrol agents, including their formulation, reproducibility under field conditions, environmental variability, regulatory considerations for some microbial agents, and limitations, are also highlighted and discussed. Finally, further research suggestions are made for the future control of tomato root rot caused by R. solani. This review provides a basis for the field application of biocontrol agents to control tomato root rot caused by R. solani. Full article