Pathogens最新文献

The discrepancy between the genotypic and phenotypic expression of enterotoxins in S. aureus had long been a significant challenge in toxin detection. However, the accurate and rapid application of Raman spectroscopy for the genotypic and phenotypic characterisation of S. aureus enterotoxins remains problematic. To address this, the present study utilised a single-cell Raman spectra database from 31 S. aureus isolates, acquired via a Raman laser tweezer system. When combined with convolutional neural network analysis, this approach achieved an average accuracy of 99.71% for identifying single-gene toxin types and 99.44% for multi-gene toxin types, with an average phenotypic identification accuracy of 98.71%. Notably, the phenotypic identification accuracy for the three strains carrying the sea and seb genes reached 100%, and the validation accuracy using unknown genotypes and phenotypes exceeded 85%. Furthermore, the CNN analysis identified characteristic spectral peaks for S. aureus enterotoxin genotypes at 1663-1665 cm^-1, 1570 cm^-1, and 1117-1119 cm^-1, corresponding to protein α-helices, guanine, and nucleic acid backbones respectively. Representative peaks for the phenotype were found at 1302-1314 cm^-1 and 912-923 cm^-1, corresponding to proteins/lipids and polysaccharides, respectively. Representative peaks for different virulence phenotypes carrying multiple enterotoxin genes were located at 1074-1076 cm^-1, 1253-1255 cm^-1, 1326 cm^-1, and 1327 cm^-1, corresponding to proteins, nucleic acids, and lipids, respectively. Furthermore, metabolomic analysis of three S. aureus strains (sea+seb+, sea+seb-, sea-seb+) revealed metabolic differences in fatty acids, purines, phenylalanine, and aspartic acid, consistent with the corresponding distinct Raman spectral peaks (1458, 1179, 1406-1409 cm^-1). Thus, this study employed S. aureus as a proof-of-concept, establishing for the first time a method combining Raman laser tweezers with convolutional neural networks for identifying S. aureus enterotoxin genotypes and phenotypes. It clarified the Raman spectral differential peaks and their corresponding biomarkers among five classical enterotoxin genotypes and phenotypic strains, providing a novel approach for accurate toxin typing and virulence characterisation.

Insecticide resistance in Aedes aegypti (Linnaeus, 1762) poses a major challenge for vector control programs, undermining the effectiveness of chemical tools to mitigate both nuisance biting and the transmission of vector-borne diseases. Previous studies have documented widespread resistance to multiple adulticide active ingredients across Florida, particularly pyrethroids, along with high prevalence of knockdown resistance (kdr) mutations. Continued resistance monitoring is essential for guiding treatment decisions and detecting shifts in susceptibility over time. In collaboration with mosquito control programs across Florida, we assessed the susceptibility of 78 Ae. aegypti populations to up to six active ingredients, conducting 396 independent CDC bottle bioassays and calculating hazard ratios relative to a susceptible Ae. aegypti strain. For pyrethroids, 24 h post-exposure mortality was used to evaluate phenotypic recovery from knockdown. Hazard ratios revealed Ae. aegypti populations were more susceptible to organophosphate adulticide active ingredients, while the lowest hazard ratios, indicating higher resistance, were observed for sumithrin, deltamethrin, etofenprox, and permethrin, respectively. Evidence of knockdown resistance and recovery after 24 h was present across all pyrethroid exposures, with the highest levels following treatment with etofenprox and sumithrin. These findings confirm that pyrethroid resistance remains a significant barrier to Ae. aegypti control and provide updated, operationally relevant resistance data that can complement existing guidance and support evidence-based vector management strategies.

Syphilis is a re-emerging sexually transmitted infection with rising incidence worldwide, often associated with HIV infection. Ocular syphilis represents a severe manifestation that can occur at any disease stage and may result in permanent vision loss if not promptly diagnosed and treated. We conducted a retrospective comparative cohort study of 22 patients with ocular syphilis managed at Istanbul University, Istanbul Faculty of Medicine, between 2019 and 2025. Twelve patients (54.5%) were people living with HIV (PLWH). The majority were male (81.8%), with a mean age of 45.2 years. Visual loss was observed in more than half of the patients and occurred significantly more frequently in PLWH than in HIV-negative individuals (100% vs. 70%; p = 0.046). Vitritis was also significantly more frequent among PLWH (91.7% vs. 40%; p = 0.02), indicating more severe intraocular inflammation. All six cases of neurosyphilis were confined to PLWH (50% vs. 0%; p = 0.004). The most common ocular manifestations were uveitis (90.9%), predominantly panuveitis and posterior uveitis. All patients received intravenous penicillin G or ceftriaxone, and systemic corticosteroids were administered in half of the cases. Clinical improvement was observed in all patients. Our findings highlight that ocular syphilis in PLWH is associated with more severe inflammation and higher neurosyphilis risk, underscoring the importance of routine cerebrospinal fluid examination and neurosyphilis-based treatment strategies in this group.

Background: Enterococcus species are involved in urinary tract infections (UTIs), and they are known to be intrinsically resistant to certain antibiotics. We aimed to investigate the clinical characteristics and treatment outcomes of enterococcal UTIs in three hospitals in Saudi Arabia and Oman.

Methods: A retrospective cohort study was conducted on adults with clinically and microbiologically confirmed enterococcal UTI based on urinary symptoms and a urine culture of ≥100,000 CFU/mL, who received an antibiotic active against the pathogen. The primary endpoint was clinical cure. Secondary endpoints included microbiological cure, length of stay (LOS), in-hospital mortality, and recurrence.

Results: E. faecalis and E. faecium were isolated from 188 (67.1%) and 92 (32.9%), respectively, of 280 included patients. Ampicillin/amoxicillin (25%) and vancomycin (22.1%) were the most-used antibiotics. Compared with E. faecium, E. faecalis was associated with higher clinical cure rates (75% vs. 57.6%; p = 0.003), lower in-hospital mortality (15.7% vs. 38.5%; p < 0.0001), and shorter LOS (12.5 vs. 25 days; p < 0.0001). No difference in recurrence was observed. Ciprofloxacin was associated with high odds of clinical cure (OR, 4.28; 95% CI, 1.18-15.56). Conversely, the recent cancer chemotherapy and growth of Enterococcus at another site were associated with lower odds of clinical cure. Urinary catheter removal was associated with lower recurrence odds (OR, 0.48; 95% CI, 0.24-0.98).

Conclusions: This study highlights the clinical challenges posed by enterococcal UTIs, particularly by E. faecium. Ciprofloxacin remains an effective option, particularly against E. faecalis. Patients with advanced age, critical illness, complicated infections, and liver disease, as well as patients on hemodialysis, require close monitoring to improve outcomes.

Hepatitis A virus (HAV) infection can occasionally cause acute severe hepatitis. Patients with this disease sometimes need to undergo liver transplantation with immunosuppressants. Although rare, breakthrough HAV infections, despite vaccination, appear to be more common among immunocompromised populations. The effect of immunosuppressants on HAV replication is unclear. In this study, we examined the effects of immunosuppressants on HAV HA11-1299 genotype IIIA replication in human hepatocytes, finding that azathioprine inhibited HAV replication with a half-maximal inhibitory concentration of 0.967 μmol/L. We further examined the effect of azathioprine on the replication of HAV HM175 18f genotype IB using replication-competent or replication-incompetent subgenomic replicon in HuhT7 cells. Azathioprine had significant inhibitory effects on the HAV replication-competent subgenomic replicon compared to the replication-incompetent subgenomic replicon. The effect of azathioprine on the activity of the HAV HM175 18f genotype IB-internal ribosomal entry site (IRES) was investigated in COS7-HAV-IRES cells using a reporter assay. Azathioprine at 1 μmol/L had a significant inhibitory effect on HAV IRES activity but at 0.5 μmol/L had no inhibitory effect. Azathioprine appears to inhibit HAV replication as well as HAV translation. In conclusion, we found that azathioprine inhibits HAV replication in human hepatocytes, meaning that it may be useful for patients with a HAV infection who need to use immunosuppressants.

Loop-mediated isothermal amplification (LAMP) is an innovative nucleic acid amplification technique that operates under isothermal conditions and is distinguished by its high analytical efficiency, cost-effectiveness, and operational simplicity. Unlike conventional molecular assays, LAMP does not require sophisticated instrumentation or highly specialized personnel, rendering it particularly suitable for diagnostic deployment in resource-limited settings. Reaction outcomes are typically determined through direct visual inspection, often via colorimetric readouts, further enhancing its applicability in decentralized and point-of-care contexts. Owing to these attributes, LAMP has emerged as a valuable tool for the diagnosis of infectious diseases, particularly in regions with constrained laboratory infrastructure. Its affordability, rapid turnaround time, and ease of implementation support large-scale testing during public health emergencies, including epidemics and outbreaks, thereby contributing to the reduction in disease burden. Timely and accurate pathogen detection using LAMP can substantially strengthen public health responses aimed at controlling and mitigating viral transmission. This review provides an overview of the LAMP methodology, with an emphasis on its application in the detection of viral pathogens with epidemic and pandemic potential. Dengue virus and influenza virus are discussed as representative model infections to illustrate the diagnostic performance and practical advantages of LAMP-based assays. In addition, we explore current challenges and future perspectives for the implementation of LAMP in resource-limited settings, highlighting the need for continued technological refinement and contextual adaptation to maximize its impact on global health initiatives.

Salmonella Minnesota (SM) is considered an emerging serovar, adapted to the poultry production chain, frequently associated with antimicrobial resistance, biofilm formation, and environmental persistence. This study aimed to characterize SM isolates from a poultry slaughterhouse regarding phenotypic and genotypic profiles of antimicrobial resistance, biofilm-forming capacity, thermal tolerance, genotypic virulence profile, and clonal relatedness. Strains obtained from carcasses (n = 26), cecal contents (n = 25), and chiller water (n = 11) from the slaughterhouse were evaluated. A high frequency of resistance to β-lactams, multidrug-resistant phenotypes, and extended-spectrum β-lactamase-producing isolates were observed. All isolates harbored genes associated with virulence and biofilm formation (invA, csgD, and adrA). Biofilm formation was influenced by temperature, with greater intensity at refrigeration temperatures, especially on stainless steel surfaces. In thermal tolerance assays, a negative correlation between temperature and bacterial viability was observed. Genetically related lineages circulating among cecum, carcass, and slaughterhouse chiller water over time were observed. These findings indicate that the persistence of SM in poultry slaughterhouses is sustained by the interaction between antimicrobial resistance, adaptive capacity associated with biofilm formation, and the circulation of genetically related lineages, representing a relevant challenge for food safety and public health.

Healthcare-associated infections remain a central hospital challenge, particularly in critical areas where invasive procedures and microbial contamination overlap. The hospital environment, including air and high-touch surfaces, acts as a persistent microorganism source that favors stability and spread. UV-C disinfection systems have become complementary tools to conventional cleaning. This study evaluated the disinfectant efficacy of a 254 nm multiemitter UV-C system under in situ and in vitro conditions. A 254 nm UV-C multiemitter system was deployed to eight hospital areas selected for epidemiological relevance. Air and surface sampling were conducted before and after standardized UV-C cycles. The bacterial and fungal aerobiome was quantified (CFU/m³) and surfaces were characterized by MALDI-TOF mass spectrometry. In vitro assays tested efficacy against planktonic cultures and mature biofilms of clinical ESKAPE isolates and C. albicans. The UV-C intervention achieved mean aerobiome reductions above 91.5%, with complete elimination in multiple critical zones. Surface contamination was reduced by 96.1%, including total disinfection across several sampled points. In vitro testing showed ≥99.99% to 100% elimination of planktonic microorganisms. Mature biofilms exhibited full loss of viability after UV-C exposure, independent of biofilm architecture and structural complexity. Therefore, the 254 nm UV-C multiemitter system significantly reduced environmental microbial burden in critical hospital areas, supporting its integration within infection-prevention programs and reinforcing environmental biosafety through the control of the microbial sources involved in transmission dynamics.

Woody tissue diseases of avocado (Persea americana Mill. var. Hass) pose a major phytosanitary threat due to their chronic progression, late symptom expression, and severe impact on tree stability and productivity. Although white rot has traditionally been attributed to saprobic basidiomycetes, increasing evidence suggests corticioid fungi may act as facultative pathogens in agricultural systems. This study examined corticioid basidiomycetes associated with white rot in stems and branches of avocado in Michoacán, Mexico. Field surveys revealed consistent symptoms of structural weakening, branch dieback, and wood decay. Fungal isolates obtained from symptomatic tissues and sporomes were characterized morphologically and identified through ITS-based phylogenetic analyses. Representative isolates of Grammothele spp. and Dentocorticium portoricense were evaluated in pathogenicity assays under controlled conditions. All isolates reproduced field symptoms, confirming pathogenicity, though aggressiveness varied. D. portoricense exhibited the highest incidence, severity, and AUDPC values, indicating greater virulence, while Grammothele isolates showed slower, moderate progression. Phylogenetic analyses provided robust support for D. portoricense, whereas Grammothele was resolved at genus level. Integration of field, pathogenicity, and molecular data demonstrates corticioid fungi are not merely secondary saprotrophs but relevant pathogens in avocado white rot. These findings highlight the need to include corticioid fungi in diagnostic, monitoring, and management strategies for trunk and branch diseases.

Minute virus of canines (MVC) is an autonomous canine parvovirus that causes severe pathological outcomes, including embryo mortality, spontaneous abortion, and congenital malformations in neonatal puppies. Although MVC infection has been shown to induce host cell cycle arrest and apoptosis, the underlying regulatory mechanisms that coordinate cell proliferation and control apoptotic responses during viral replication remain poorly understood. Sirtuin 1 (SIRT1) is an NAD⁺-dependent deacetylase that plays a critical role in regulating cell cycle progression, DNA damage responses, and apoptosis. However, its involvement in MVC infection has not been fully elucidated. Herein, we show that MVC infection markedly upregulates the mRNA and protein expression levels of SIRT1 in a time-dependent manner. MVC infection activates the SIRT1-p53 signaling axis and modulates the acetylation status of p53. In addition, MVC alters the subcellular distribution of SIRT1, promoting its nuclear translocation and colocalization with the viral protein VP2. Functional analyses demonstrated that pharmacological activation of SIRT1 enhanced the viability of MVC-infected WRD cells (virus-tropic cell), promoting viral replication, prolonging S-phase arrest, and reducing apoptosis. Conversely, inhibition of SIRT1 produced the opposite effects, which were closely associated with regulation of the SIRT1-p53 signaling axis. Moreover, SIRT1 knockdown accelerated apoptosis and attenuated S-phase arrest, whereas SIRT1 overexpression further strengthened S-phase retention. Collectively, our findings identify the SIRT1-p53 signaling axis as an important regulator of cell cycle progression and apoptosis during MVC infection, highlighting SIRT1 as a key host factor that supports viral replication and persistence and a potential target for antiviral intervention.