Search Results (495)

The emergence of multidrug-resistant Pseudomonas strains poses a serious threat to public health. Essential oil components, such as thymol (TH), exhibit potent antibacterial activity. However, the effects of continuous sublethal TH exposure and resulting changes to antibiotic susceptibility remain poorly understood. Here, we investigated a multi-resistant Pseudomonas psychrophila strain after TH adaptation using an integrated transcriptomic and metabolomic approach. Treatment with TH caused a significant decrease in MIC values for aminoglycosides (streptomycin, gentamicin, kanamycin) and tetracycline and increased susceptibility to five other antibiotics. Multi-omics analyses revealed coordinated changes in fatty acid metabolism (FabI downregulation and accumulation of unsaturated fatty acids), lipid A biosynthesis (LpxC downregulation), peptidoglycan synthesis (Mur genes downregulated, accompanied by increased spermine levels), and stress response pathways (such as GABA, GadA, maltose, and MalK). These results suggest that metabolic alterations and envelope remodeling potentially affect cell wall integrity and growth, which could, in turn, contribute to increased antibiotic susceptibility and re-sensitization. Overall, our findings highlight the potential of TH-mediated sensitization as a complementary strategy to restore antibiotic efficacy. Full article

Background: Wrist osteomyelitis caused by Scedosporium apiospermum is exceedingly rare. Its indolent course and destructive potential may result in extensive bone loss and pose substantial diagnostic and therapeutic challenges. Methods: We report a case of chronic wrist osteomyelitis caused by Scedosporium apiospermum in a 68-year-old kidney–pancreas transplant recipient. Results: Following diagnosis, systemic antifungal therapy with voriconazole was initiated, and multiple surgical debridements were performed to achieve local disease control, resulting in a large defect of the carpus and distal forearm. Hand salvage was attempted using an osteocutaneous triple-barrel fibula flap. The postoperative course was complicated by congestion of the fibula skin island, which was managed with leech therapy. Subsequent infection with a multi-resistant Aeromonas spp. and Morganella morganii led to flap necrosis, ultimately requiring transradial forearm amputation. Conclusions: Destructive Scedosporium apiospermum osteomyelitis in immunocompromised patients is a major challenge for reconstructive surgeons. Interdisciplinary management is essential as mold eradication is only achievable through a combined surgical and antimicrobial approach. In advanced destructive osteomyelitis, the choice between limb salvage and amputation should be individualized, considering patient comorbidities, reconstructive risk, and patients’ preferences. This case highlights the importance of balancing careful indication and patient counseling in complex clinical scenarios. Full article

In this study, a survey was conducted in 14 fields (6 in Thessaloniki and 8 in Serres) before barley harvest during three growing seasons (2019–20, 2020–21, 2021–22) to map the occurrence of ACCase and ALS multi-resistant populations and evaluate the influence of agronomic practices and environmental conditions on their dynamics. Specifically, weed cover and tiller number/plant were assessed in each field using a W pattern, while questionnaires were used to collect information from farmers on agronomic practices applied, such as seedbed preparation, the rate of fertilization at sowing, the time of sowing, the time and rate of top-dressing nitrogen fertilizer, the time of application of the herbicide pinoxaden, and the harvest time. Soil properties and climatic conditions were also recorded. These results indicated that regardless of the different agricultural practices applied in the fields of the studied regions, no significant association was found with L. rigidum’s ground cover or number of tillers/plant. Additionally, no association was identified between weed ground cover and climatic characteristics. Therefore, the findings of this study strongly support the dependence of the dispersal of the resistant strain L. rigidum on the interactions between genetic, biological, and soil factors; fertilizer or herbicide use; sowing or other agronomic practices; and climatic factors that drive resistance dynamics, rather than any individual practice alone. Full article

Bacterial resistance on farms can be driven by antimicrobial use. Less is known about inter-farm transfer of resistance genes and their persistence under low antimicrobial pressure. Over two years and nine visits, we examined the shedding of resistant indicator bacteria (Escherichia coli) on one lower- and one higher-antimicrobial-usage pig farm. There was a unidirectional transfer of some less healthy pigs from the former to the latter. Faecal pools (180) were cultured on Chromagar ECC, with and without added cefotaxime or ciprofloxacin. Presumptive E. coli were phenotyped, and many ciprofloxacin-resistant isolates were whole-genome sequenced. Comparing farms, there was more (p < 0.0001) phenotypic resistance to the antimicrobial panel from the higher-usage unit, and markedly more (about ten-fold) multi-resistance. Significantly elevated individual drug resistances on this unit correlated with recently used antimicrobials. Ciprofloxacin and/or cefotaxime-resistant isolates were often present, although in low proportions. Neither of these antimicrobial classes had been administered recently, except for one fluoroquinolone course late in the study. AMR genes were more diverse from the higher-usage farm, but some resistant and multi-resistant isolates were closely related between farms. Thus, we demonstrated the maintenance of resistance genes in strains present on farms, even where selective pressure was low. Full article

The development of antimicrobial resistance (AMR) and the emergence of multiresistant pathogens represent a growing global threat to both human and animal health. Beyond the excessive and improper use of antimicrobials in human medicine, irrational use in veterinary medicine, agriculture, and aquaculture significantly contributes to the selection and spread of resistant microorganisms, which can enter the food chain and reach humans through food consumption or handling. Based on results from a recent meta-analysis, the prevalence of antimicrobial-resistant foodborne pathogens in food samples exceeds 10%. The veterinary sector is of particular concern, as a large proportion of antimicrobials are used in animal production, generating strong selective pressure and favoring the dissemination of AMR along the food chain. In an increasingly interconnected global context, resistant pathogens and resistance determinants can disseminate rapidly across sectors and national borders, making strategies confined to a single sector insufficient; therefore, effectively addressing AMR requires a One Health approach encompassing the human, veterinary, and environmental domains. Key mitigation strategies include strengthening antimicrobial stewardship programs, also in animal production, reducing routine prophylactic use of antimicrobials, and improving surveillance, coordinated across sectors and, where possible, further supported by advanced technologies such as artificial intelligence and machine learning. Further efforts are also needed to improve microbiological diagnostics, particularly through rapid and molecular methods, to support timely, targeted therapies and reduce inappropriate empirical treatments. In parallel, investment in new therapeutic options, including innovative molecules, drug combinations, and alternative approaches, remains crucial to effectively countering the growing burden of antimicrobial resistance. Full article

Corynebacterium lactis was isolated from the skin abscess of a companion dog and from raw milk of a cow with unspecific mastitis. As information about the species was scarce and a zoonotic potential could not be excluded, we started a basic characterization of C. lactis strain RW3-42 with respect to antibiotic susceptibility and the response of invertebrate animal model systems to infection. C. lactis showed a number of antimicrobial resistances and is able to colonize Caenorhabditis elegans. In contrast, Galleria mellonella larvae were not impaired by C. lactis. Genome analyses of strain RW2-5 revealed the absence of toxin-encoding genes, and only a rather small number of other virulence factors were found, i.e., SpaA- and SpaH-type pili and the non-fimbrial adhesins DIP0733, DIP1281, DIP1621 and EmbC in addition to a homologue of Salmonella RhuM involved in killing of C. elegans. The results obtained indicate a limited pathogenic potential of the species. Full article

Downy mildew, caused by Plasmopara viticola, is a devastating disease that threatens global grape production, with chemical control remaining the most effective management strategy. However, the repeated application of fungicides has led to widespread resistance in P. viticola populations, while data on the resistance of P. viticola to metalaxyl (MET), cymoxanil (CYM), and cyazofamid (CYA) in China remain limited. In this study, the resistance status of P. viticola to these three fungicides was evaluated across 9 major grape-growing regions in China using leaf-disc bioassays, and potential cross- and multi-resistance patterns were assessed. The majority of isolates (127/233) exhibited either lower resistance (33.48%) or moderate resistance (21.03%) to MET based on the minimum inhibitory concentration (MIC) of 10 μg/mL and 100 μg/mL. Baseline sensitivity profiles for CYM and CYA were established as 8.69 ± 0.64 μg/mL and 0.42 ± 0.05 μg/mL, respectively, using 170 and 137 isolates. The total resistance frequency of P. viticola to CYM was 29.42% (21.18% low resistance, 8.24% moderate resistance), while that to CYA was 28.47% (18.25% low resistance, 9.49% moderate resistance, 0.73% high resistance). A weak but significant positive correlation was detected between CYM and CYA sensitivities (r = 0.193, p = 0.0196), and 13 isolates exhibited resistance to both fungicides, indicating potential multi-resistance risk. Significant regional differences in resistance profiles were observed among populations (p < 0.05), and no overall fitness penalties were detected. These findings highlight the necessity of region-specific and integrated resistance management strategies for sustainable control of grape downy mildew in China. Full article

Background: Staphylococci, recognized for their virulence and antibiotic resistance, are important in both human and veterinary medicine. Loss of sensitivity to beta-lactam antibiotics, such as ampicillin, complicates therapy, prompting the search for alternative antibacterials or ways to increase drug efficacy. Silver and gold nanoparticles (AgNPs, AuNPs) are promising on their own or in combination with antibiotics. Methods: The aim of this study is to compare the biological activity of pure, washed AgNPs and AuNPs with biosynthesized nanoparticles from Alchemilla vulgaris (AgNPs-Av and AuNPs-Av). Their antibacterial, antibiofilm, and biofilm-eradication effects on the tested antibiotic-resistant, biofilm-forming staphylococci (Methicillin-resistant Staphylococcus aureus (MRSA) and multiresistant Non-aureus staphylococci and mammaliicocci (NASM)) were evaluated using in vitro microdilution methods. Results: AgNPs-Av and AuNPs-Av inhibited bacterial growth at 50 μg/mL, while a significant suppression of biofilm formation was observed at just 25 μg/mL. Our research showed that neither AuNPs-Av nor AuNPs disrupts bacterial biofilm. AgNPs-Av effectively eradicated the biofilm at 50 μg/mL. NPs and ampicillin at subinhibitory antibiotic concentrations against the tested staphylococci. The results showed significant antibacterial and antibiofilm effects (p = 0.001). Partially, biofilm-eradication activity and strong antibiotic potentiation were also detected. Conclusions: These findings highlight the importance of rational combination therapy to improve antibiotic effectiveness and reduce bacterial resistance. Full article

(1) Background: We sought to explore the changes in the biomolecular profile and morphology of Pathogenic heat-resistant E. coli isolated from animal-based food. (2) Methods: Six strains underwent heat (60 °C for 6 min), ultrasound (US; 299 W), UVC (4950 mJ/cm²), and combined treatments (UVC+US and heat+UVC). Afterwards, biomolecular characterization across four spectral regions was evaluated by Fourier transform infrared (FT-IR) spectroscopy and analyzed by principal component analysis (PCA) for treated and non-treated strains (control group). These regions are fatty acids (3010–2800 cm⁻¹), proteins and peptides (1700–1200 cm⁻¹), carbohydrates (1200–900 cm⁻¹), and amide A (3280–3120 cm⁻¹). Additionally, treated and untreated strains were assessed for surface damage using scanning electron microscopy (SEM). (3) Results: Among all the regions studied, the amide A and fatty acids regions exhibited the most significant variations in absorbance for treated strains compared to the control. Treatments such as US, heat, and UVC+US tended to increase Principal Components (PCs) and, consequently, absorbance. On the other hand, UVC and heat+UVC showed the opposite trend in these regions. SEM images showed filamentous cells for strains treated with UVC and UVC+US, indicating that cells continued to replicate under these conditions. These results highlight how thermal and non-thermal treatments influence specific biomolecular and morphological regions of E. coli. The methodologies used provide reliable data for understanding stress responses, which can guide the development of more effective technologies for eliminating multi-resistant pathogens. Full article

The aim of this work was to evaluate the microbiological quality of Spanish aged cheeses and the antimicrobial resistance of enterococci, staphylococci and Enterobacterales. A total of 60 aged cheeses produced in northern Spain were collected at the retail level. Mesophiles, lactic acid bacteria, staphylococci, enterococci, Enterobacterales, and yeast counts were determined. More microbial diversity was found in raw milk cheeses than in those elaborated with pasteurized milk. In general, lactic acid bacteria were the dominant microorganism, mainly Lactiplantibacillus lactis. High resistance rates were observed in E. faecalis strains isolated from raw milk cheeses (74.42%), being 9.30% multi-resistant. The dominant staphylococci found was Staphylococcus equorum. Multi-resistant S. equorum strains were isolated both from raw (1.69%) and pasteurized milk cheeses (9.09%). Hafnia alvei was the predominant bacterium in raw milk cheeses. Fifteen Enterobacterales strains, isolated from raw milk cheeses, showed multi-resistance (37.5%), and seven strains were ESBL producers (17.5%). Escherichia coli was only isolated from 5. 56% of raw milk cheeses, but all of them were extended-espectrum B-lactamase (ESBL) producers. The dominant yeast was D. hansenni, followed by Kluyveromyces lactis. Full article

Antibiotic-resistant, biofilm-forming Escherichia coli may constitute a reservoir of antibiotic resistance and other determinants that can be transmitted to pathogenic bacteria for animals and humans. Therefore, it is crucial to reduce the incidence of these types of E. coli. The aim of this study was to determine whether essential oils from oregano, thyme, sage, and coriander, as well as the postbiotic substance PS412, can inhibit virulence factor genes possessing pig-derived E. coli. It aimed to find a new tool for the prevention and/or elimination of virulent E. coli. Altogether, 16 pig-derived E. coli from a pig farm in the region of Vojvodina (Serbia) were taxonomically identified using MALDI-TOF mass spectrometry; 14 strains (87.5%) with secure genus identification/probable species identification and 2 with highly probable genus identification. The fimA gene was detected in 62.5% of E. coli strains, and the crl gene in 87.5% of the strains. Ec3419/2 contained five analyzed genes. Five E. coli were found to form biofilm, as indicated by their growth on Congo red agar. The strains were mostly multi-resistant to antibiotics. Each E. coli strain produced the damaging enzyme, such as β-glucuronidase and/or α-chymotrypsin. However, they were susceptible to herbal essential oils (HEOs) with average inhibitory zones from 15 to 27 mm in diameter. They were also (6) susceptible to the PS412 (activity to 6400 AU/mL). The results contribute to the practical effectiveness of postbiotic substances, HEOs, and their combination as a novel approach to combating the virulence factors of E. coli. This insight also contributes to the strategy behind the One Health Concept. Full article

Quorum-sensing (QS) systems play a crucial role in regulating virulence, biofilm formation, and antibiotic resistance in clinically relevant microbes. This review explores the potential of QS systems as targets for developing novel plant-based therapeutic strategies using bioinformatics, aimed at combating highly pathogenic bacteria: uropathogenic Escherichia coli (UPEC) and Pseudomonas aeruginosa. We examine the key components and molecular pathways of QS systems in these microbes, including autoinducer synthases, receptors, and regulatory proteins. In UPEC, we discuss the LuxS-dependent autoinducer (AI)-2 system, while for P. aeruginosa, we analyze the more complex interconnected Las, Rhl, and PQS circuits. We highlight how these systems control the expression of virulence factors and contribute to biofilm formation, emphasizing their importance in pathogenesis. Furthermore, we explore bioinformatics approaches for identifying and characterizing QS components, i.e., by predicting protein structures and interactions. The potential of in silico screening for QS inhibitors is also discussed, along with challenges and opportunities in targeting QS systems for therapeutic interventions. By integrating microbiological, molecular, and computational perspectives, this review aims to provide insights into the application of bioinformatics in understanding and targeting QS systems in these clinically significant pathogens. The goal is to facilitate the development of novel anti-virulence approaches in search of novel antibiotics that could complement or replace traditional antibiotic treatments, addressing the growing concern of antimicrobial resistance in these clinically relevant microbes. Full article

Background: Sepsis remains a leading cause of morbidity and mortality, particularly when caused by multidrug-resistant organisms (MDROs). Early identification of colonising or infecting pathogens may inform initial antimicrobial selection. Surveillance cultures, providing microbiological data prior to infection onset, could guide timely and targeted therapy. This retrospective study analysed routine surveillance culture results from patients with bloodstream infection (BSI) episodes, assessing pathogen prevalence, resistance phenotypes, and concordance with specimen type in haemato-oncology (HO) and acute care (AC) settings. Methods: Data were retrieved from the institutional Laboratory Information System of the Department of Clinical Microbiology and ATB Centre, General University Hospital in Prague, covering 1 January to 31 December 2024. All positive blood cultures containing ESCAPE pathogens (excluding Clostridioides difficile) were reviewed. Corresponding surveillance culture records were analysed to evaluate concordance with subsequent BSI episodes. Results: In 2024, 6046 AC and 7267 HO surveillance cultures were performed; MDRO prevalence was 5% and 6.56%, respectively. ESBL-producing Enterobacterales predominated (AC 86.9%, HO 81.6%). In HO, BSI-causing Gram-negative and Gram-positive pathogens were frequently detected in rectal swabs, whereas in AC, concordance was higher with upper and lower respiratory tract samples. Rectal screening detected 100% of E. coli and K. pneumoniae BSI episodes in HO. Other specimen types showed limited concordance. Conclusions: Surveillance culture utility varies by specimen type and clinical setting. In both HO and AC units, these cultures provided valuable insights into colonisation and resistance patterns, supporting early risk stratification and guiding initial therapy in high-risk patients. Full article

Genetic diversity and kinship information of cotton germplasm resources are fundamental to breeding, providing a theoretical basis for the rational selection of hybrid parents and further breeding of new varieties with high yield, high quality, and multi-resistance. This study utilized cotton varieties that have been used for variety improvement or are widely planted in the Northern Xinjiang cotton region as materials. Genotyping was performed using the ZJU CottonSNP40K chip to analyze genetic diversity and kinship relationships. A total of 26,852 high-quality SNP markers were obtained, including 15,222 SNPs in subgenome A and 11,630 SNPs in subgenome D. The number of SNPs per chromosome ranged from 547 (A04) to 2168 (A08). Based on phylogenetic tree and principal component analysis, the 83 materials were clustered into 3 major subgroups. Group I contained varieties introduced from the former Soviet Union and the United States, which have become important parents for cotton breeding in Northern Xinjiang. Among them, as many as 27 varieties were derived and selected from the introduced US variety ‘Beiersinuo’ as a parent. While playing an important role in cotton breeding in Northern Xinjiang, this has also led to the current situation where the genetic base of Northern Xinjiang varieties is relatively narrow (average kinship coefficient 0.72). It clarifies the significant role of introduced American variety ‘Beiersinuo’ in the breeding of Northern Xinjiang cultivars and provides theoretical guidance for broadening the genetic base of Northern Xinjiang cotton varieties. Full article

Pseudomonas aeruginosa is a well-studied bacterium, recognized as a primary infectious agent due to its capacity to form multi-resistant biofilms. Various strategies to inhibit the pathogenic activity and biofilm formation of Pseudomonas aeruginosa are under investigation. This study examines the interaction between these pathogenic biofilms and the antibiotic Tobramycin, both in the presence and absence of supernatants from the probiotic organism, Lactiplantibacillus plantarum, using Fourier transform infrared (FTIR) spectroscopy. A Universal Attenuated Total Reflection accessory enabled rapid acquisition of infrared spectra from Pseudomonas aeruginosa biofilms grown on Teflon membranes and subsequently exposed to antibiotic and/or probiotic agents. Spectral changes induced by these agents were analyzed using deconvolution procedures, difference spectra, and ratiometric analysis. The results show that antibiotic treatment modifies the lipid, protein, nucleic acid, and carbohydrate components of bacterial biofilms. Specifically, the spectral analysis suggests that antibiotic treatment alters membrane structural organization, inhibits protein synthesis, and affects sugar and polysaccharide production. Additional treatment with a probiotic agent further changes the characteristics of the bacterial biofilm. FTIR spectroscopy with the Attenuated Total Reflection spectra collection geometry is confirmed as an effective method for rapid spectral acquisition and the use of Teflon membranes further facilitates the application of this vibrational technique in microbiology. Full article