Pathogens最新文献

Canine visceral leishmaniasis (CVL), caused by Leishmania infantum, is a multisystemic disease in which ocular involvement is frequent but often underestimated. This study aimed to comprehensively evaluate the clinical, ophthalmological, parasitological, hematological, biochemical, and histopathological alterations in dogs naturally infected with L. infantum from an endemic area of northeastern Brazil, with special emphasis on the relationship between ocular manifestations and systemic disease. Twenty-five symptomatic dogs were evaluated through clinical and ophthalmological examinations, parasitological culture, PCR, laboratory analyses, and histopathology of ocular and periocular tissues. Ocular alterations were observed in 80% of the animals, predominantly bilateral and frequently associated with multiple concurrent lesions, including ocular discharge, conjunctivitis, blepharitis, uveitis, and corneal opacity. Functional ophthalmological tests revealed keratoconjunctivitis sicca and corneal ulcers in a substantial proportion of dogs. Hematological abnormalities were highly prevalent, particularly anemia and thrombocytopenia. Comparative analysis demonstrated that dogs with ocular involvement exhibited significantly higher leukocyte counts and segmented neutrophils, as well as increased AST levels, indicating an enhanced systemic inflammatory response. Histopathological examination revealed intense plasmacytic inflammatory infiltrates and the presence of amastigote forms in ocular and periocular tissues, indicating that both immune-mediated and parasite-driven mechanisms could be involved in disease pathogenesis. Collectively, these findings underscore ocular involvement as a clinically relevant manifestation of CVL and reinforce the importance of routine ophthalmological evaluation in clinical management.

Candida albicans is an opportunistic fungus capable of forming biofilms that are resistant to conventional antifungal treatments. This study evaluated the antibiofilm activity of an ethanolic extract from Mexican oregano (Lippia graveolens Kunth) stem and its impact on the protein composition of the C. albicans cell wall (CW). The proteomic analysis was restricted to the adherent cells that persisted after treatment, representing the more tolerant subpopulation. First, the biofilm-forming capacity of 18 clinical isolates was characterized. Subsequently, the effect of the Lippia graveolens Kunth stem extract on biofilm formation was assessed in clinical isolates of C. albicans with high and moderate biofilm-forming capacities. The results showed an MIC₉₀ of 16 mg/mL against C. albicans isolates in planktonic growth. Furthermore, the extract exhibited an antibiofilm effect, showing a 77% inhibition in the highly biofilm-forming C. albicans 2400H strain at 1.6 mg/mL. To assess how the extract influences CW composition, we analyzed the CW proteome of the adherent biofilm cells of C. albicans that persisted after exposure to the stem extract. Mass spectrometry identified 1006 total proteins, where 156 were up-regulated, and 94 were down-regulated. Of the differentially expressed proteins, we identify 40 CW proteins (CWP's) associated with dimorphic transition, adhesion, oxidative stress, and biofilm formation. These findings provide the potential of the L. graveolens Kunth stem as a natural antifungal agent against C. albicans biofilms. In addition, we identified CWP's associated with tolerance to the extract's antibiofilm activity, offering mechanistic insight into persistence and potential targets for improving antibiofilm interventions.

Respiratory infections are a leading cause of hospitalization and mortality in children, and the pediatric intensive care unit (PICU) is a critical setting for managing severe cases. However, the epidemiological patterns of respiratory pathogens in the PICU remain insufficiently characterized. In this retrospective study, we analyzed respiratory pathogen testing results from 2126 pediatric patients admitted to the PICU of Wuhan Children's Hospital between 2019 and 2024. The pathogen spectrum and epidemiological characteristics were evaluated across age groups and seasons. Respiratory syncytial virus (RSV, 18.06%) was the most frequently detected viral pathogen, while Streptococcus pneumoniae (6.96%) was the predominant non-viral pathogen. The overall infection burden was highest in children aged ≤ 1 year (53.75%) and 3 < age ≤ 6 years (54.70%), indicating that early childhood represents a high-risk period for severe respiratory infections requiring intensive care. Pathogen distribution varied significantly across age groups. Distinct seasonal patterns were observed for several respiratory pathogens, particularly among viral pathogens, whereas non-viral pathogens showed more variable seasonal distributions. Furthermore, screening for 10 common pathogens accounted for 75% of PICU respiratory infections, highlighting the clinical utility of multiplex molecular detection. This study delineates the pathogen spectrum of respiratory tract infections in the PICU and characterizes their age- and season-specific epidemiological patterns. This study defines the pathogen spectrum and age- and season-specific patterns of respiratory infections in the PICU, providing evidence to support targeted pathogen surveillance, optimized multiplex diagnostics, and risk-informed infection control strategies in pediatric critical care.

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.

Toxoplasmosis is an insidious globally distributed zoonosis accounting for approximately one-fifth of all foodborne illnesses in humans in Europe. It stands as a classic example of a disease transmitted through the close interconnection between humans, animals, and the environment. Accordingly, mitigation strategies and health management protocols demand cross-sectoral involvement from medical, veterinary, environmental, and political actors, rendering the adoption of a 'One Health' perspective essential. Despite longstanding advocacy for One Health by the WHO, WOAH, and FAO, national health authorities have yet to establish the necessary operational infrastructure. Specifically, there is a lack of tools to enable information sharing among professionals, which is essential for the synergistic management of major health issues. A four-part epidemiological data collection tool specifically developed for human toxoplasmosis is proposed here to aid in the identification of risk factors and potential sources of infection. The proposed framework comprises four sequential sections intended to be completed through contribution from the patient, the attending physician, the involved veterinarian, and the national reference laboratory for toxoplasmosis. This questionnaire serves as a conceptual, non-validated tool designed to support a One Health-oriented epidemiological investigation process. Its practical performance, feasibility, and potential usefulness in routine surveillance or prevention strategies have not yet been assessed and will require validation in future studies. Nonetheless, the framework may serve as a model for the development of similar integrative tools applicable to other zoonotic diseases.

Bloodstream infections (BSI) carry high mortality, but traditional blood culture is too slow for urgent clinical needs. This study aims to develop a rapid point-of-care testing assay based on one-tube multiplex nested polymerase chain reaction (PCR) (OM-NPCR-POCT) for early diagnosis of three pathogens in bloodstream infection patients: Escherichia coli (ECO), Klebsiella pneumoniae (KPN), and Streptococcus pneumoniae (SPN). The analytical sensitivity of the one-tube multiplex nested PCR (OM-NPCR) was evaluated using recombinant bacterial plasmids. The analytical sensitivity of the OM-NPCR-POCT assay was assessed using simulated samples. The clinical performance was evaluated in 90 clinical blood samples, with results compared to conventional quantitative PCR (qPCR). Finally, the agreement between the two detection methods was assessed via Kappa analysis. The limits of detection (LODs), calculated from serial dilution experiments, were 4, 2, and 1 copies/μL for plasmids ECO, KPN, and SPN, respectively. The OM-NPCR-POCT assay achieved LODs of 20, 10, and 10 CFU/mL for ECO, KPN, and SPN in simulated samples, with a total testing time of approximately 2 h. The clinical evaluation of OM-NPCR-POCT demonstrates consistency with conventional qPCR while exhibiting higher sensitivity. This method has potential as a rapid diagnostic tool for early bloodstream infection detection.

Throughout history, species within the genus Entamoeba have been described using criteria that were not always applied consistently, resulting in an often confusing and controversial taxonomy. Several factors contributed to this situation, including the limited number of morphological characters available for taxonomic studies, overlapping host ranges, mixed infections, and a cosmopolitan distribution associated with human and animal movements. The incorporation of genetic data as diagnostic and differential criteria during the second half of the twentieth century enabled the recognition of cryptic species and the proposal of new taxa; however, significant taxonomic issues remain unresolved. This review summarizes the historical development and major controversies in the taxonomy of Entamoeba, from its origins in the late nineteenth century, when morphology and host association were the available criteria, to the present day, in which molecular approaches provide a more realistic view of species diversity and interspecific relationships. Based on this analysis, general principles are proposed as a pragmatic synthesis to guide future taxonomic work on Entamoeba, emphasising lineage-based species delimitation, the central role of molecular evidence when diagnostic morphology is lacking, the contextual value of host data, and the need for nomenclatural decisions grounded in biological evidence and historical rigour.

Healthcare-associated bacterial conjunctivitis is an underrecognized yet preventable infection in neonatal intensive care units (NICUs). This study aimed to determine the incidence, risk factors, microbiological profile, and treatment approaches of healthcare-associated bacterial conjunctivitis in neonates. This descriptive, cross-sectional study included neonates diagnosed with bacterial conjunctivitis and followed in the NICU between January 2019 and January 2024. Pathogens were identified by MALDI-TOF MS and antimicrobial susceptibility determined using VITEK 2 according to EUCAST breakpoints. During the five-year period, 104 (2.5%) of 4107 neonates admitted to the NICU developed healthcare-associated bacterial conjunctivitis. Of the pathogens isolated in cultures, 70.2% were Gram-positive bacteria, with coagulase-negative staphylococci being the most common (52.9%), followed by Staphylococcus aureus, Klebsiella pneumoniae, and Serratia marcescens. Empirical treatment consisted of 0.3% topical gentamicin eye drops. In resistant cases, fortified vancomycin drops (32.7%), 0.5% moxifloxacin (4.8%), or 0.3% tobramycin (1.9%) eye drops were administered according to antibiogram results. Compared with Gram-positive infections, Gram-negative conjunctivitis was associated with longer durations of intubation, orogastric feeding, and hospitalization. These findings indicate a predominance of Gram-positive pathogens in NICU-acquired neonatal conjunctivitis, while Gram-negative infections confer greater clinical burden. Fortified antibiotic eye drops are an effective treatment option for resistant cases in high-risk newborns.

Tick-borne pathogens pose a significant threat to human health. In this study, a multiple droplet digital PCR (ddPCR) assay was developed to detect four tick-borne pathogens: Borrelia burgdorferi sensu lato (Bbsl), Coxiella burnetii (C. burnetii), spotted fever group Rickettsia (SFGR), and Borrelia miyamotoi (B. miyamotoi). Based on the singleplex ddPCR reaction system of Bbsl, the primer probes of the other three species were incorporated to develop a multiplex ddPCR reaction system. The annealing temperature and the final concentration of the primer probes were then optimized for multiplex ddPCR. The multiplex ddPCR assay was assessed for its sensitivity, specificity, repeatability, and ability to detect simulated and actual samples. The developed multiplex ddPCR approach enables the simultaneous detection of Bbsl, C. burnetii, SFGR, and B. miyamotoi. The positive target microtitre clusters are closely grouped and distinctly separated from each other, with the multiplex ddPCR assay demonstrating a dynamic range of five orders of magnitude. The limits of detection (LOD) for the multiplex ddPCR assay were 4 copies/20 µL for Bbsl, 3 copies/20 µL for C. burnetii, 3 copies/20 µL for SFGR, and 2 copies/20 µL for B. miyamotoi. The assay demonstrated high specificity, with no observed cross-reactivity against non-target pathogens. Performance was validated using both spiked samples and field-collected clinical specimens. In the evaluation of 30 ticks and 30 serum samples, the ddPCR method (in both singleplex and multiplex formats) achieved higher positive detection rates for all four target pathogens compared to quantitative real-time PCR (qPCR). In addition, the detection proportions of multiplex and singleplex ddPCR were consistent. Multiplex ddPCR can detect low DNA concentrations in samples and enables the absolute quantification of Bbsl, C. burnetii, SFGR, and B. miyamotoi, providing a novel detection approach for the clinical diagnosis of tick-borne diseases.