Microorganisms最新文献

Alfalfa anthracnose is an economically significant disease that leads to substantial biomass losses due to stem rot, reduced stand longevity, and a decline in forage nutritional quality. The disease is caused by multiple species within the genus Colletotrichum, including the 14 described species: C. gloeosporioides, C. truncatum, C. lindemuthianum, C. destructivum, C. dematium, C. trifolii, C. medicaginis, C. graminicola, C. coccodes, C. sojae, C. spinaciae, C. lini, C. americae-borealis, and C. tofieldiae. A thorough understanding of key aspects of the pathogen's biology, along with its epidemiology, infection cycle, and accurate disease diagnosis, is essential for the development of sustainable management strategies. Knowledge of these factors allows us to anticipate disease outbreaks, implement timely interventions, and design integrated control measures that reduce reliance on chemical fungicides while maintaining crop productivity and forage quality. Although anthracnose management has traditionally relied on synthetic fungicides, this review synthesizes alternative control strategies to clarify the current state of knowledge and to provide new insights into the development of effective and sustainable approaches for managing Colletotrichum species.

The U94 protein of Human Herpesvirus 6 exerts antiproliferative effects through downregulation of the Src proto-oncogene. We aimed to define the shortest U94 fragment that preserves antiproliferative activity and to explore its structural properties. U94 was truncated into shorter fragments, which were subjected to computational analyses and proliferation assays on MDA-MB-468, BT-549 breast cancer cells. Src phosphorylation levels were scrutinized by Western blot analysis. Data obtained demonstrated that the U94 antiproliferative activity resides in its N-terminal region. Specifically, MT153 (aa 1-153) and MT117 (aa 1-117) fragments exhibited antiproliferative activity, whereas MV85 (aa 1-85) fragment did not. Computational analyses identified MG112 (aa 1-112) and MI108 (aa 1-108) as biologically active and suggested that the β-sheet of the structure is critical. The shortest KI95 fragment (aa 14-108), maintaining a stable β-sheet, demonstrated antiproliferative effects and Src downregulation. The antiproliferative activity of U94 and its active fragments relies on stable tridimensional conformation rather than on linear peptide sequence. KI95 represents the shortest active U94 fragment that preserves biological function, with critical residues likely located within the β-sheet region. These findings highlight the importance of structural integrity in U94 functionality and suggest KI95 as a potential therapeutic agent for cancer treatment.

The Leizhou goat is a vital indigenous breed, yet its disease resilience can complicate early health monitoring. The white blood cell (WBC) count is a key indicator of immune status, but its relationship with the gut microbiota remains uncharacterized in this breed. This study aimed to characterize the fecal microbiota of Hainan black goats stratified based on their WBC counts. The goats were stratified into Lower, Middle, and High WBC groups based on peripheral WBC counts to compare their fecal microbiota and identify potential associations with systemic immunity. Significant differences in microbial alpha- and be-ta-diversity were observed among the groups, with the High WBC group showing the greatest richness. The microbiota was dominated by Bacillota and Bacteroidota at the phylum level. Linear discriminant analysis Effect Size (LEfSe) identified specific taxa en-riched in each group, such as Ruminococcusin the High WBC group. Critically, Spearman correlation analysis demonstrated significant positive correlations between WBC counts and the relative abundance of genera like unclassified_f_Oscillospiraceae and unclassi-fied_c_Clostridia. These findings demonstrate that WBC counts are significantly associated with distinct shifts in the gut microbial community structure of Hainan black goats. The identified WBC-associated microbial biomarkers suggest a link between the gut microbi-ome and host immune regulation, providing a foundation for future research on microbi-ota-mediated health assessment in goats.

The escalating threat of antibiotic resistance, particularly from Staphylococcus aureus (S. aureus), has become a critical challenge in both public health and animal husbandry. The extensive use of conventional antibiotics in livestock production accelerates the emergence of resistant strains, heightening risks to food safety and human health. Although plant-derived bioactive compounds are increasingly recognized as promising alternatives to synthetic antimicrobials, the mechanisms underlying their efficacy-and the potential for synergistic action among different plant parts-remain poorly understood. In particular, the antibacterial interactions among extracts from different tissues of Cyperus esculentus L. (C. esculentus), a plant rich in flavonoids and phenolics, have yet to be systematically evaluated. Here, we investigated the antibacterial properties and mechanisms of ethanol extracts from the tubers, stems-leaves and their mixture of C. esculentus against S. aureus. Using Oxford cup diffusion assays, scanning electron microscopy (SEM), bacterial growth kinetics, and untargeted metabolomics, we assessed both phenotypic inhibition and metabolic disruption. The mixed extract exhibited the strongest antibacterial effect, producing a 26.15 mm inhibition zone-approximately 7% greater than that of single-part extracts-and induced cell wall rupture and disintegration as observed by SEM. Growth curve analyses revealed time-dependent bacterial suppression, while metabolomic profiling identified 845 differential metabolites, indicating disturbances in amino acid, lipid, and nucleotide metabolism. Flavonoids such as acacetin, diosmetin, naringenin, and silybin A were identified as principal active compounds contributing to these effects.

Mycoplasma synoviae (MS) is a major pathogen threatening China's poultry industry, causing severe economic losses, and clarifying its epidemiology is pivotal for disease control and flock purification. In this study, a total of 3215 chicken samples collected from 643 broiler farms across 15 provinces in China in 2024 were analyzed. PCR detected 14% positivity (450 samples), and 18 isolates obtained from these positive samples (4.0% isolation rate). Multilocus sequence typing (MLST, 7 housekeeping genes) and neighbor-joining phylogenetic analysis (integrating 425 reference sequences from public databases) identified 13 distinct sequence types (STs), demonstrating considerable genetic diversity among circulating MS strains. Pathogenicity assessment of the five isolates revealed that the infected chickens exhibited varying degrees of infectious synovitis, while no respiratory signs were observed. In addition, antimicrobial susceptibility testing against 10 commonly used antibiotics was conducted on the 18 strains, providing urgently needed guidance for rational drug use in the clinical treatment of both breeder and broiler flocks. This large-scale epidemiological study yields crucial insights into the current prevalence and genetic diversity of MS in China and lays a scientific foundation for formulating targeted prevention strategies and optimizing management practices.

This study aimed to investigate the structural differences and functional potential of the gut microbiota between Sichuan-Tibetan black pigs (n = 5) and Landrace pigs (n = 5) under identical rearing conditions. Fecal samples were collected and subjected to 16S rRNA gene sequencing followed by comprehensive bioinformatics analysis. The results revealed 963 and 910 operational taxonomic units (OTUs) in Sichuan-Tibetan black pigs and Landrace pigs, respectively, with 808 OTUs shared between the two breeds. While both breeds shared Firmicutes, Bacteroidota, and Proteobacteria as the dominant phyla, significant compositional differences were observed at the genus level. Sichuan-Tibetan black pigs exhibited higher abundance of Escherichia-Shigella, Streptococcus, Prevotella, Parabacteroides, and Collinsella, whereas Landrace pigs were enriched in Bacteroides. Alpha diversity analysis showed no significant differences in Shannon, Simpson, or ACE indices, though the Chao index differed markedly between the two groups. Beta diversity analysis (PCoA and NMDS) confirmed distinct microbial community structures between the breeds. Functional prediction analysis demonstrated that metabolic pathways dominated in both groups, but with notable functional differentiation: the microbiota of Sichuan-Tibetan black pigs showed significant enrichment in biosynthesis of secondary metabolites, microbial metabolism in diverse environments, and amino acid biosynthesis; whereas, Landrace pigs were characterized by enhanced carbon and energy metabolism pathways. Additionally, BugBase phenotype prediction revealed significant differences in stress tolerance, cell wall properties, and oxygen utilization capabilities between the two groups. These findings provide valuable insights into the breed-specific characteristics of gut microbiota in swine and establish a foundation for further research on host-microbe interactions and their implications for animal health and nutrition.

Klebsiella pneumoniae is commonly known to cause a vast range of community-acquired or nosocomial infections. The isolation of K. pneumoniae has also been noted in diseased food-producing animals, including swine. The main goals of this study were to document clinical manifestation of a septicaemia outbreak in suckling piglets due to K. pneumoniae ST25 and provide molecular characterisation of the isolates. For the purpose of this investigation, 13 dead suckling piglets with cyanosis were selected. All the isolates obtained from affected lungs were susceptible to apramycin, ceftiofur, gentamycin, neomycin, and spectinomycin, presented intermediate susceptibility to florfenicol, and were resistant to other tested antibiotics. Histopathological examination of lungs, kidneys, and livers revealed lesions typical of septicaemia. MLST analysis of the isolates demonstrated a complex metabolic profile of the bacteria with genes attributable to the hypervirulent phenotype. To the best of our knowledge, we documented the first outbreak of K. pneumoniae septicaemia in suckling piglets reared in Poland.

Clinical data on antimicrobial profiles are useful for dairy udder health treatment programmes and represents a component of antimicrobial stewardship. The study aimed to determine the bacterial aetiology of clinical mastitis in dairy herds in Western Australia and to evaluate their antibiotic resistance profiles. This retrospective study utilised clinical antimicrobial profile data from two referral diagnostic centres within the region of Western Australia. A total of 545 mastitic samples were submitted for antimicrobial culture and testing over a period of 10 years (2008-2018). Of these, 406 showed bacterial growth and 139 no bacterial growth was observed. The most common isolates were Streptococcus uberis (25.3%), Staphylococcus aureus (17.2%), and Escherichia coli (9.4%). No growth was identified in 25.5% of the mastitis milk samples. The antimicrobial profiles revealed high susceptibilities towards cefuroxime (95.7%), clavulox (89.4%), and oxytetracycline (89%), whilst showing high resistance towards novobiovin (70%). From this study, it is concluded that there was a decline in the resistance trends towards the isolates of both S. uberis and S. aureus over the 10-year period and contagious mastitis had a higher occurrence. There is a need to consider surveillance programmes that determine the patterns of on-farm antimicrobial usage and further characterise the pathogens based on the presence of resistance antimicrobial genes. Data on antimicrobial surveillance represent an important component of antimicrobial stewardship.

In the original publication, there was a mistake in Figure 7B as published [...].

Escherichia coli is an important human pathogen that is able to cause a variety of infections, which can result in diarrhoea, urinary tract infections, sepsis, and even meningitis, depending on the pathotype of the infecting strain. Like many Gram-negative bacteria, E. coli is becoming increasingly resistant to many frontline antibiotics, including third-generation cephalosporins and carbapenems, which are often considered the antibiotics of last resort for these infections. This is particularly the case in Egypt, where multidrug-resistant (MDR) E. coli is highly prevalent. However, in spite of this, few Egyptian MDR E. coli strains have been fully characterised by genome sequencing. Here, we present the genome sequences of ten highly MDR E. coli strains, which were isolated from children who presented with diarrhoea at the Outpatients Clinic of Assiut University Children's Hospital in Assiut, Egypt. We report that they carry multiple antimicrobial resistance genes, which includes extended spectrum β-lactamase genes, as well as bla_NDM and bla_OXA carbapenemase genes, likely encoded on IncX3 and IncF plasmids. Many of these strains were also found to be high-risk extra-intestinal pathogenic E. coli (ExPEC) clones belonging to sequence types ST167, ST410, and ST617. Thus, their presence in the Egyptian paediatric population is particularly worrying, and this highlights the need for increased surveillance of high-priority pathogens in this part of the world.