Search Results (1,097)

Enterococcus spp. are opportunistic and nosocomial pathogens. Intensive pig farms have been recently described as important hotspots for antibiotic resistance and reservoirs of potentially pathogenic enterococci, including other species than the most known E. faecalis and E. faecium. Here, we identified Linezolid-resistant non-E. faecalis and E. faecium (NFF) Enterococcus strains isolated from different production stages (suckling piglets, weaning pigs, and fatteners) across six intensive pig farms. The transferability of the linezolid-resistance determinants was assessed by bacterial conjugation and strains were also characterized for biofilm production, hemolytic and gelatinase activity. Among 64 identified NFF Enterococcus strains, 27 were resistant to at least three different antibiotic classes and 8/27 specifically to Linezolid. E. gallinarum and E. casseliflavus both transferred their Linezolid resistance determinants to the main pathogenic species E. faecium. Remarkably, this is the first report of the optrA gene transfer from E. casseliflavus to E. faecium by conjugation, which can greatly contribute to the spread of antibiotic resistance genes among pathogenic enterococcal species. The “weaning pigs” stage exhibited a significantly higher number of antibiotic-resistant enterococci than the “fatteners”. These findings highlight the importance of monitoring pig farms as hotspots for the spread of antibiotic-resistant enterococci, especially in the early stages of production. Furthermore, they underscore the significant role of NFF Enterococcus species as carriers of antibiotic resistance genes, even to last-resort antibiotics, which may be transferable to the major enterococcal species. Full article

Buffalo mozzarella cheese whey (CW) and ricotta cheese exhausted whey (RCEW) are valuable by-products of the Mozzarella di Bufala Campana PDO production chain. This study characterized their microbial communities using an integrated culture-dependent and -independent approach. Metabarcoding analysis revealed that the dominance of lactic acid bacteria (LAB), including Streptococcus thermophilus, Lactobacillus delbrueckii, and Lactobacillus helveticus, alongside diverse heat-resistant yeasts such as Cyberlindnera jadinii. Culture-based isolation identified subdominant lactic acid bacteria strains, not detected by sequencing, belonging to Leuconostoc mesenteroides, Enterococcus faecalis, and Enterococcus durans. These strains were further assessed for their probiotic potential. E. faecalis CW1 and E. durans RCEW2 showed tolerance to acidic pH, bile salts, and lysozyme, as well as a strong biofilm-forming capacity and antimicrobial activity against Bacillus cereus and Staphylococcus aureus. Moreover, bile salt resistance suggests potential functionality in cholesterol metabolism. These findings support the potential use of CW and RCEW as reservoirs of novel, autochthonous probiotic strains and underscore the value of regional dairy by-products in food biotechnology and gut health applications. Full article

Feline urinary tract infections (UTIs) present a common challenge in veterinary practice, underscoring the importance of understanding local bacterial pathogens and antimicrobial resistance (AMR). This study determined bacterial prevalence and antimicrobial susceptibility in cats at Kasetsart University’s Veterinary Teaching Hospital in Bangkok, Thailand. Of the 543 cystocentesis urine samples collected from 428 cats, 115 (21.2%) tested positive for bacterial cultures, leading to a diagnosis of UTIs in 95 cats (22.2%). The most prevalent isolates included Escherichia coli (24.8%), Staphylococcus species (19.2%), Proteus mirabilis (13.6%), Pseudomonas aeruginosa (12.0%), and Enterococcus species (12.0%). Staphylococcus felis (8.8%) and Staphylococcus pseudintermedius (5.6%) were the predominant Staphylococcus species. Rare pathogens such as Corynebacterium urealyticum and Lactococcus garvieae were also identified. Antimicrobial testing revealed alarming resistance, with 69.2% of isolates exhibiting multidrug resistance (MDR). Escherichia coli and Proteus mirabilis showed high resistance to amoxicillin/clavulanic acid (AMC) (45.2–70.6%) and sulfamethoxazole/trimethoprim (SXT) (51.6–52.9%). Enterococcus faecium exhibited 85.7% resistance to AMC. Methicillin resistance was identified in 41.7% of Staphylococcus isolates, particularly high in Staphylococcus epidermidis (75.0%) and Staphylococcus pseudintermedius (71.4%). High fluoroquinolone resistance among MDR isolates further exacerbates AMR concerns. These results indicate that MDR Gram-negative, Staphylococcus, and Enterococcus species complicate the empirical treatment of feline UTIs, highlighting significant implications for AMR in veterinary practice. Full article

The yak (Bos grunniens) is a key species in high-altitude rangelands of Asia. Despite their ecological and economic importance, yak production faces persistent challenges, including low milk yields, vulnerability to climate changes, emerging diseases, and a lack of systematic breeding programs. This review presents the genomic, physiological, and environmental dimensions of yak biology and husbandry. Genes such as EPAS1, which encodes hypoxia-inducible transcription factors, underpin physiological adaptations, including enlarged cardiopulmonary structures, elevated erythrocyte concentrations, and specialized thermoregulatory mechanisms that enable their survival at elevations of 3000 m and above. Copy number variations (CNVs) and single nucleotide polymorphisms (SNPs) present promising markers for improving milk and meat production, disease resistance, and metabolic efficiency. F1 and F2 generations of yak–cattle hybrids show superior growth and milk yields, but reproductive barriers, such as natural mating or artificial insemination, and environmental factors limit the success of these hybrids beyond second generation. Infectious diseases, such as bovine viral diarrhea and antimicrobial-resistant and biofilm-forming Enterococcus and E. coli, pose risks to herd health and food safety. Rising ambient temperatures, declining forage biomass, and increased disease prevalence due to climate changes risk yak economic performance and welfare. Addressing these challenges by nutritional, environmental, and genetic interventions will safeguard yak pastoralism. This review describes the genes associated with different yak traits and provides an overview of the genetic adaptations of yaks (Bos grunniens) to environmental stresses at high altitudes and emphasizes the need for conservation and improvement strategies for sustainable husbandry of these yaks. Full article

Hemolin has been identified as a crucial immune gene in insect immune defense. The silkworm is susceptible to infections by pathogenic microorganisms when reared on artificial diets. In this study, through comparative analysis of the expression patterns of BmHemolin in silkworms fed on mulberry leaves and artificial diets, we found that the expression of BmHemolin was significantly upregulated in silkworms reared on artificial diets, and this upregulation was highly likely induced by pathogenic microorganisms. Further interaction analysis revealed that BmHemolin could bind to pathogenic microorganisms and form aggregates. Meanwhile, BmHemolin enhanced the melanization and aggregation of hemocytes. Subsequent in vitro antibacterial experiments showed that BmHemolin had the ability to inhibit the growth of Escherichia coli. In vivo clearance experiments demonstrated that BmHemolin facilitated the clearance of pathogens in the body. Moreover, CRISPR/Cas9-mediated knockout of the BmHemolin gene led to the downregulation of antimicrobial peptides and phagocytosis-related factors, while an excess of BmHemolin could enhance the expression of these genes, thereby improving the silkworm’s immune resistance to Enterococcus mundtii and increasing survival rates. In summary, our research demonstrates that BmHemolin played a pivotal role in both humoral and cellular immunity in the silkworm, thereby defending against pathogen invasion. Full article

Water supply and sewage drainage pipes have a critical role to play in the provision of clean water and sanitation, and pipe material selection influences infrastructure life, water quality, and microbial communities. Zinc-containing compounds are highly valued due to their mechanical properties, anticorrosion behavior, and antimicrobial properties. However, the effect of zinc salts, such as zinc sulfate heptahydrate and zinc chloride, on biofilm-forming bacteria, including Escherichia coli and Enterococcus faecalis, is not well established. This study investigates the antibacterial properties of these zinc salts under simulated pipeline conditions using minimum inhibitory concentration assays, biofilm production assays, and antibiotic sensitivity tests. Findings indicate that zinc chloride is more antimicrobial due to its higher solubility and bioavailability of Zn²⁺ ions. At higher concentrations, zinc salts inhibit the development of a biofilm, whereas sub-inhibitory concentrations enhance the growth of biofilm, suggesting a stress response in bacteria. zinc chloride also enhances antibiotic efficacy against E. coli but induces resistance in E. faecalis. These findings highlight the dual role of zinc salts in preventing biofilm formation and modulating antimicrobial resistance, necessitating further research to optimize material selection for water distribution networks and mitigate biofilm-associated risks in pipeline systems. Full article

Objective: This study aimed to evaluate the in vitro efficacy of silver nanoparticles (AgNPs) synthesized by bioreduction using lemongrass (Cymbopogon citratus) essential oil against multidrug-resistant (MDR) bacteria isolated from an Intensive Care Unit (ICU). Methods: The essential oil was extracted and characterized by gas chromatography–mass spectrometry (GC-MS). Antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and total phenolic content. AgNPs (3 mM and 6 mM silver nitrate) were characterized by UV-Vis spectroscopy, dynamic light scattering (DLS), zeta potential, transmission electron microscopy (TEM), and Fourier-transform infrared (FTIR) spectroscopy. Bacterial isolates were obtained from ICU surfaces and personal protective equipment (PPE). Results: The essential oil presented citral A, citral B, and β-myrcene as major components (97.5% of identified compounds). AgNPs at 3 mM showed smaller size (87 nm), lower Polydispersity Index (0.14), and higher colloidal stability (−23 mV). The 6 mM formulation (147 nm; PDI 0.91; −10 mV) was more effective against a strain of Enterococcus spp. resistant to all antibiotics tested. FTIR analysis indicated the presence of O–H, C=O, and C–O groups involved in nanoparticle stabilization. Discussion: The higher antimicrobial efficacy of the 6 mM formulation was attributed to the greater availability of active AgNPs. Conclusions: The green synthesis of AgNPs using C. citratus essential oil proved effective against MDR bacteria and represents a sustainable and promising alternative for microbiological control in healthcare environments. Full article

Background: Antimicrobial resistance (AMR) is increasingly acknowledged as a critical global challenge, posing serious risks to human and animal health and potentially disrupting poultry production systems. Commensal bacteria such as Staphylococcus spp., Enterococcus spp., and Escherichia coli may serve as important reservoirs and vectors of resistance genes. Objectives: This study aimed to assess the AMR profiles of bacterial strains isolated from industrial chicken farms in the Dél-Alföld region of Hungary, providing region-specific insights into resistance dynamics. Methods: A total of 145 isolates, including Staphylococcus spp., Enterococcus spp., and E. coli isolates, were subjected to minimum inhibitory concentration (MIC) testing against 15 antimicrobial agents, following Clinical and Laboratory Standards Institute (CLSI) guidelines. Advanced multivariate statistics, machine learning algorithms, and network-based approaches were employed to analyze resistance patterns and co-resistance associations. Results Multidrug resistance (MDR) was identified in 43.9% of Staphylococcus spp. isolates, 28.8% of Enterococcus spp. isolates, and 75.6% of E. coli isolates. High levels of resistance to florfenicol, enrofloxacin, and potentiated sulfonamides were observed, whereas susceptibility to critical antimicrobials such as imipenem and vancomycin remained largely preserved. Discussion: Our findings underscore the necessity of implementing region-specific AMR monitoring programs and strengthening multidisciplinary collaboration within the “One Health” framework with proper animal hygiene and biosecurity measures to limit the spread of antimicrobial resistance and protect both animal and human health. Full article

Unconventional food plants (UFPs) are increasingly valued for their nutritional composition and bioactive potential. This study proposes a comprehensive characterization of the chemical and bioactive properties of Pereskia aculeata Miller (Cactaceae) (PA); Xanthosoma sagittifolium (L.) Schott (Araceae) (XS); Stachys byzantina K. Koch (Lamiaceae) (SB); and inflorescences from three cultivars of Musa acuminata (Musaceae) var. Dwarf Cavendish, var. BRS Platina, and var. BRS Conquista (MAD, MAP, and MAC), including the assessment of physical, nutritional, phytochemical, and biological parameters. Notably, detailed phenolic profiles were established for these species, many of which are poorly documented in the literature. XS was characterized by a unique abundance of C-glycosylated flavones, especially apigenin and luteolin derivatives, rarely described for this species. SB exhibited high levels of phenylethanoid glycosides, particularly verbascoside and its isomers (up to 21.32 mg/g extract), while PA was rich in O-glycosylated flavonols such as quercetin, kaempferol, and isorhamnetin derivatives. Nutritionally, XS had the highest protein content (16.3 g/100 g dw), while SB showed remarkable dietary fiber content (59.8 g/100 g). Banana inflorescences presented high fiber (up to 66.5 g/100 g) and lipid levels (up to 7.35 g/100 g). Regarding bioactivity, PA showed the highest DPPH radical scavenging activity (95.21%) and SB the highest reducing power in the FRAP assay (4085.90 µM TE/g). Cellular antioxidant activity exceeded 2000% in most samples, except for SB. Cytotoxic and anti-inflammatory activities were generally low, with only SB showing moderate effects against Caco-2 and AGS cell lines. SB and PA demonstrated the strongest antimicrobial activity, particularly against Yersinia enterocolitica, methicillin-resistant Staphylococcus aureus (MRSA), and Enterococcus faecalis, with minimum inhibitory concentrations ranging from 0.156 to 0.625 mg/mL. Linear discriminant analysis revealed distinctive chemical patterns among the species, with organic acids (e.g., oxalic up to 7.53 g/100 g) and fatty acids (e.g., linolenic acid up to 52.38%) as key discriminant variables. Overall, the study underscores the nutritional and functional relevance of these underutilized plants and contributes rare quantitative data to the scientific literature regarding their phenolic signatures. Full article

Antibiotic resistance is one of the most significant public health issues today. As a consequence, there is an urgent need for novel classes of antibiotics. This necessitates the development of highly efficient screening methods for the rapid identification of antibiotic-producing bacteria. Here, we describe a new method for high-throughput screening of antimicrobial compounds (AMC) producing halophilic bacteria. Our methodology used a newly designed 3D-printed Petri plate replicator used for drop deposition and colony replication. We employed this device in combination with a modified agar overlay assay to screen more than 7400 bacterial colonies. A total of 54 potential AMC producers were discovered at a success rate of 0.7%. Although 40% of them lost their antibacterial activity during the secondary screening, 22 strains retained inhibitory activity and were able to suppress the growth of one or more safe relatives of the ESKAPE group pathogens. The ethyl acetate extract from the most potent strain, Virgibacillus salarius POTR191, demonstrated moderate antibacterial activity against Enterococcus faecalis, Acinetobacter baumanii, and Staphylococcus epidermidis with minimal inhibitory concentrations of 128 μg/mL, 128 μg/mL, and 512 μg/mL, respectively. We propose that our replica plate assay could be used for target-based antimicrobial screening of various extremophilic bacteria. Full article

The role of Enterococcus spp. in food is debated since this group of lactic acid bacteria contains opportunistic pathogenic strains, some of which exhibit a multidrug-resistant profile. In livestock farms, the use of antibiotics is the most common practice to deal with mastitis-causing bacteria. However, the heavy usage and/or misuse of antibiotics has led to the emergence of antibiotic resistance. This study aimed to genetically and phenotypically characterize Enterococcus strains isolated from raw sheep milk. Samples were collected over one year from the bulk tank of a dairy sheep farm and cultured on selective media. Isolates were purified and analyzed by whole-genome sequencing and antimicrobial susceptibility testing. The isolates were divided into clusters and the corresponding species were identified along with their genes related to virulence and antibiotic resistance. The pan-, core- and accessory-genomes of the strains were determined. Finally, the antibiotic-resistant profile of selected strains was examined and associated with their genomic characterization. These findings contribute to a better understanding of Enterococci epidemiology, providing comprehensive profiles of their virulence and resistance genes. The presence of antibiotic-resistant bacteria in raw sheep milk destined for the production of cheese should raise awareness. Full article

Copper-based substances have historically been shown to exhibit antimicrobial properties, but the mechanisms by which they interact with bacterial biofilms in pipeline systems remain unclear. This study investigates the effects of copper sulfate and copper nitrate on the growth, biofilm formation, and antibiotic resistance profiles of Escherichia coli and Enterococcus faecalis. Across a wide concentration range (0.00005–100 mg/mL), both salts demonstrated strong antimicrobial activity at higher concentrations, while sublethal levels produced more nuanced effects. Higher concentrations exhibited potent antimicrobial activity, while sublethal concentrations paradoxically enhanced biofilm resistance, particularly in E. faecalis. Growth kinetic assays and spectroscopic analysis were used to better understand how copper interacts with microbes on a biochemical and physical level. Surprisingly, prolonged exposure to sublethal copper concentrations altered the antibiogram profiles of E. faecalis, developing resistance to ceftazidime. The findings confirm the bimodal activity of copper salts as antimicrobial and biofilm-controlling agents, highlighting the critical need for precise concentration optimization in wastewater treatment. This current study contributes to the collective knowledge pool of metal–microbe interactions, shedding light on selecting materials for industrial and environmental applications. Full article

Background/Objectives: Multidrug-resistant (MDR) bacterial colonization poses a significant risk for subsequent infections, especially within hospital environments. Healthcare workers can inadvertently transmit these MDR bacteria to vulnerable patients, exacerbating the problem. This study aimed to determine the colonization rates of MDR bacteria among patients and healthcare workers in a rural Ethiopian hospital with limited resources. Methods: Between 26 May and 6 June 2024, nasal, rectal, vagino-rectal exudate, and stool samples were collected from patients (n = 78) and healthcare workers (n = 11) at Gambo General Hospital (Oromia Region, Ethiopia). Samples were cultured on chromogenic media selective for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), and carbapenemase-producing Enterobacteriaceae (CPE). Bacterial identification was performed using MALDI-TOF mass spectrometry (Bruker), antimicrobial susceptibility testing using the MicroScan WalkAway system (Beckman Coulter), and genotypic characterization with the MDR Direct Flow Chip kit (Vitro). Results: MRSA nasal colonization was detected in 43.3% of patients (13/30; 95% CI: 27.4–60.8%) and 27.3% of healthcare workers (3/11; 95% CI: 6.0–61.0%) (p = 0.73). Rectal (or stool) colonization by MDR bacteria was significantly higher in pediatric patients (85.0%, 17/20; 95% CI: 62.1–96.8%) than in adults (14.3%, 4/28; 95% CI: 5.7–31.5%) (p < 0.001). Notably, a high proportion of pediatric patients harbored Escherichia coli strains co-producing NDM carbapenemase and CTX-M ESBL, and VRE strains were also predominantly isolated in this group. Conclusions: This study reveals a concerningly high prevalence of MRSA and MDR Enterobacteriaceae, especially among children at Gambo Hospital. The VRE prevalence was also substantially elevated compared to other studies. These findings underscore the urgent need for strengthened infection control measures and antimicrobial stewardship programs within the hospital setting. Full article

Oral microbiota have been implicated in pancreatic ductal adenocarcinoma (PDAC) and may contribute to chemotherapy resistance. While previous studies attributed bacteria-induced resistance to indirect host modulation, recent findings suggest a direct mechanism. Escherichia coli expressing long-form cytidine deaminase (CDD_L) can degrade gemcitabine, a chemotherapeutic agent, into a non-toxic form, leading to resistance. In contrast, bacteria carrying short form (CDD_S) or lacking CDD did not induce resistance. This study investigates whether oral bacteria can cause gemcitabine resistance in PDAC cells through CDD-mediated degradation. Oral microbes associated with PDAC were selected based on CDD isoforms: Aggregatibacter actinomycetemcomitans carrying CDD_L, Enterococcus faecalis, Streptococcus mutans, Porphyromonas gingivalis, all carrying CDD_S, and Fusobacterium nucleatum lacking CDD. The selected microbes, along with wild-type and CDD-deficient E. coli, were co-incubated with gemcitabine to assess its degradation and PDAC cell proliferation. A. actinomycetemcomitans fully degraded gemcitabine and induced resistance. Surprisingly, CDD_S-expressing oral bacteria partially degraded gemcitabine in a strain-dependent manner. Expressing either CDD_L or CDD_S in CDD-deficient E. coli resulted in equivalent gemcitabine degradation and resistance, indicating that CDD function is independent of isoform length. These findings highlight the role of oral bacteria in gemcitabine resistance and the need for strategies to mitigate microbial-driven resistance in PDAC treatment. Full article

The repurposing potential of Efavirenz (EFV), a clinically established non-nucleoside reverse transcriptase inhibitor, was comprehensively evaluated for its in vitro antibacterial effect either alone or in combination with other antibacterial agents on several Gram-positive clinical strains showing different antibiotic resistance profiles. The binding potential assessed by an in silico study included Penicillin-binding proteins (PBPs) and WalK membrane kinase. Despite the relatively high minimum inhibitory concentration (MIC) limiting the use of EFV as a single antibacterial agent, it exhibits significant synergistic activity at sub-MIC levels when paired with various antibiotics against Enterococcus species and Staphylococcus aureus. EFV showed restored sensitivity of β-lactams against Methicillin-resistant S. aureus (MRSA). It increased the effectiveness of antibiotics tested against Methicillin-sensitive S. aureus (MSSA). It also helped to overcome the intrinsic resistance barrier for several antibiotics in Enterococcus spp. In silico binding studies aligned remarkably with experimental antimicrobial testing results and highlighted the potential of EFV to direct the engagement of PBPs with moderate to strong binding affinities (pK_a 5.2–6.1). The dual-site PBP2 binding mechanism emerged as a novel inhibition strategy, potentially circumventing resistance mutations. Special attention should be paid to WalK binding predictions (pK_a = 4.94), referring to the potential of EFV to interfere with essential regulatory pathways controlling cell wall metabolism and virulence factor expression. These findings, in general, suggest the possibility of EFV as a promising lead for the development of new antibacterial agents. Full article