Background The Enterobacter cloacae complex (ECC) is an opportunistic pathogen frequently associated with nosocomial infections. Colistin is considered a last-resort antimicrobial for multidrug-resistant Gram-negative infections; however, the emergence and dissemination of plasmid-mediated colistin resistance genes, particularly mcr variants, have raised significant public health concerns. Among these, mcr-10 has been increasingly detected in ECC isolates from diverse clinical and environmental sources, underscoring the importance of genomic surveillance to elucidate its genetic context and transmission potential. Methods Swab samples were collected from a kitchen sink and cultured for bacterial isolation, followed by species identification using MALDI-TOF MS. Antimicrobial susceptibility was determined by the broth microdilution method, with results interpreted according to EUCAST and CLSI guidelines. Whole-genome sequencing was performed using a hybrid approach combining Illumina short-read and Oxford Nanopore long-read sequencing. Genome annotation and antimicrobial resistance gene detection were conducted using RAST and ResFinder, respectively. Multilocus sequence typing and plasmid replicon typing were performed using the MLST and PlasmidFinder tools. Comparative plasmid analysis was carried out with EasyFig and BLAST Ring Image Generator, while phylogenetic relationships were inferred using a cgMLST-based approach, and the resulting tree was visualized with iTOL. Results The E. kobei isolate (JX24083) exhibited resistance to β-lactams and early-generation cephalosporins but remained susceptible to colistin and polymyxin B. Whole-genome sequencing identified mcr-10.1 on an IncFIB(K)-type plasmid, designated pJX24083-mcr-10.1. Comparative analysis with mcr-10 -positive plasmids from E. kobei or IncFIB-type mcr-10 -positive plasmids from ECC revealed a conserved genetic structure, with xerC upstream and IS 26 downstream of mcr-10 . Phylogenetic analysis of JX24083 together with 48 mcr-10 -carrying ECC isolates showed that several dominant sequence types, including ST681, ST142, and ST1, were distributed across different hosts and countries, indicating the potential for international dissemination. Conclusion The identification of an environmental E. kobei isolate harboring a conserved xerC–mcr-10 plasmid backbone, yet exhibiting phenotypic susceptibility to colistin, highlights the silent dissemination potential of mcr-10 within the ECC and underscores the necessity for sustained One Health–oriented surveillance of environmental reservoirs.

Background:Colistin‑resistant hypervirulent carbapenem‑resistant Klebsiella pneumoniae (ColR‑hv‑CRKP) has emerged as a critical clinical challenge, yet its clinical and genomic characteristics remain poorly understood. Methods:From 2021 to 2024, 326 non-duplicate hv-CRKP isolates were collected from patients with confirmed clinical infections at a tertiary hospital in China. Antimicrobial susceptibility was determined by broth microdilution. Clinical data were retrospectively analyzed, and logistic regression identified risk factors for ColR‑hv‑CRKP infection. Whole‑genome sequencing was performed to characterize molecular characteristics and colistin resistance-associated mutations. Results:Ninety‑two isolates (92/326, 28.22%) were colistin‑resistant by broth microdilutionby. Patients with ColR‑hv‑CRKP infection were more likely to have a history of ICU admission, prolonged hospitalization, and invasive procedures, were more likely to have isolates recovered from sputum specimens, and had more frequent prior exposure to colistin (all P < 0.05). Multivariable analysis identified prior colistin administration (OR = 4.58, 95% CI 2.41-8.69) and sputum specimen source (OR = 2.44, 95% CI 1.35-4.42) as independent risk factors for ColR-hv-CRKP infection. Whole‑genome sequencing revealed that most ColR‑hv‑CRKP isolates belonged to ST11 (90/92, 97.83%), mainly KL64 (52/92, 56.52%) or KL25 (36/92, 39.13%). Carbapenem resistance was primarily mediated by bla KPC-2 (91/92, 98.91%), while no mcr genes were detected. Whole-genome sequencing analysis showed that most ColR-hv-CRKP isolates (81/92, 88.04%) harbored colistin resistance‑associated mutations. pmrB alterations were the most frequent, detected in 45.65% (42/92) of isolates, predominantly Thr157Pro (18/42) and Ser205Pro (8/42) substitutions. mgrB mutations occurred in 35.87% (33/92) of isolates, predominantly due to insertional inactivation (27/33, 81.82%) mediated by ISKpn26 and IS903B elements. Phylogenetic analysis revealed that all ST11-KL25 ColR‑hv‑CRKP isolates clustered into a highly homogeneous group with minimal intra-lineage diversity and displayed significantly smaller pairwise SNP distances than ST11-KL64/KL107 isolates (P < 0.0001). Conclusion:Colistin resistance in hv‑CRKP was mainly associated with pmrB and mgrB mutations in the dominant ST11‑KL25 and ST11‑KL64 lineages. Prior colistin exposure was the key clinical risk factor, highlighting the selective pressure of colistin use and the urgent need for strengthened antimicrobial stewardship.

Hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) poses a significant challenge in healthcare settings due to its combination of high virulence and multidrug resistance. In China, ST11 is the predominant lineage, with KL64 and the recently identified KL25 as key capsular subtypes. The clinical and genomic characteristics of ST11-KL25 remain insufficiently characterized. A total of 239 hv-CRKP isolates collected from 2020 to 2023 were analyzed. Molecular typing, antimicrobial susceptibility testing, whole-genome sequencing, and phenotypic assays were used to compare the epidemiology, resistance mechanisms, and virulence traits of ST11-KL25 and ST11-KL64. Clinical data were reviewed to assess infection characteristics. ST11 accounted for 87.9% (210/239) of hv-CRKP isolates. Among ST11 isolates, KL64 (54.7%, 104/190) and KL25 (45.3%, 86/190) were the predominant capsular types. Phylogenetic analysis suggested that ST11-KL25 may have originated from KL64 through capsular switching, with increasing prevalence after 2021. Both sublineages exhibited extensive drug resistance; however, ST11-KL64 showed broader resistance, including higher rates of ceftazidime-avibactam and polymyxin resistance. Phenotypically, ST11-KL25 demonstrated greater competitive fitness and biofilm formation, while ST11-KL64 displayed higher in vivo virulence in the Galleria mellonella model. ST11-KL25 and ST11-KL64 exhibit distinct adaptation strategies within hv-CRKP. KL25 seems to be a stable, colonization-adapted subtype with consistent resistance and moderate virulence, while KL64 is more invasive, with broader resistance and higher virulence. Subtype-specific surveillance and intervention are essential to limit their spread and protect patient and public health.

AIM:This study aimed to characterize the prevalence of fosfomycin resistance in clinical carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) isolates. METHODS:Common drug resistance genes and virulence genes were amplified by polymerase chain reaction (PCR) and verified by whole-genome sequencing. The potential virulence of all the clinical CRKP strains was tested in a Galleria mellonella infection model. RESULTS:A total of 171 CR-hvKP isolates collected from a Chinese tertiary hospital were analyzed for fosfomycin resistance. 71 strains (41.5%) were sensitive to fosfomycin, and 100 strains (58.5%) were resistant to fosfomycin. All the clinical isolates were found to carry fosfomycin genes fosA and fosA6. Only one fosfomycin-resistant isolate was found to carry the gene fosA3. In addition to the modification of target enzyme murA, the mechanisms of fosfomycin resistance also involve the dysfunction of the transport system including glpt, uhpT, and their regulatory gene CyaA mutation deletion. The Galleria mellonella infection assays confirmed that all the CRKP strains exhibited hypervirulence. CONCLUSION:Cumulatively, fosfomycin resistance in CR-hvKP is mediated by diverse mechanisms and is highly prevalent in a tertiary hospital from Jiangxi Province, South China. It is therefore critical to continuously monitor the epidemiology of these fosfomycin-resistant CR-hvKP while simultaneously minimizing potential risks from fosfomycin-resistant CR-hvKP.

Interleukin-2 (IL-2) immunotherapy offers considerable potential for metastatic cancers; however, its efficacy is limited by low response rates, dose-dependent toxicity, short half-life, poor tumor accumulation, and off-target immune activation. In this work, we present a biohybrid microrobot (IL-2@Z/C/A) engineered through biomimetic mineralization of IL-2 variant-secreting Escherichia coli Nissle 1917 (EcN) with a zeolitic imidazolate framework-8 (ZIF-8) shell coloaded with an aggregation-induced emission photosensitizer and catalase. The ZIF-8 coating preserves bacterial viability tumor-homing capability while preventing premature drug leakage and systemic exposure, thus minimizing off-target effects. Upon accumulation in the acidic tumor microenvironment (TME), the framework degrades to release engineered bacteria and therapeutic cargo. Locally delivered zinc ion release, light-triggered reactive oxygen species and EcN derived pathogen-associated molecular patterns act synergistically to induce Cle-caspase/GSDMD mediated pyroptosis, resulting in immunogenic cell death accompanied by damage-associated molecular pattern release and pro-inflammatory cytokine production. Simultaneously, catalase-driven oxygen generation alleviates hypoxia and suppresses HIF-1α-induced immunosuppression. In combination with PD-L1 blockade, IL-2@Z/C/A achieves near-complete tumor regression in a B16F10 melanoma model via a coordinated immune cascade: pyroptosis-mediated antigen exposure primes adaptive immunity, hypoxia reversal counteracts immunosuppression, and sustained local IL-2 release reverses T cell exhaustion, collectively reprogramming the immunosuppressive TME and eliciting strong antitumor immunity. This work establishes a distinct paradigm for spatially controlled immunotherapy and highlights the potential of this biohybrid microrobot in converting immunologically "cold" tumors into responsive niches.

(1) Background: Listeria monocytogenes (Lm) is recognized by the World Health Organization (WHO) as one of the four principal foodborne pathogens. This study aimed to investigate the molecular characteristics of Lm isolates from Jiaxing, China, using whole-genome sequencing (WGS) to enhance our understanding of their molecular epidemiology. (2) Methods: A total of 39 foodborne Lm isolates and 7 clinical Lm isolates were analyzed via WGS to identify resistance genes, virulence factors, lineage, sequence type (ST), and clonal complex (CC). Antibiotic susceptibility was assessed using Minimum Inhibitory Concentration (MIC) testing, and serotypes were confirmed via multiplex PCR. (3) Results: We found that 39 food isolates were mainly lineage II (66.67%), with 13 STs; ST8 was the dominant ST, and 2 new types, ST3210 and ST3405, were found. Among the seven clinical isolates, lineage I was dominant (57.14%), and ST87 was the dominant ST. Serotype 1/2a was dominant, accounting for 54.35%, followed by 1/2b, which accounted for 36.96%. The overall antimicrobial resistance rate was 13.04%, with a multidrug resistance rate of 2.17%. All strains harbored LIPI-1 and LIPI-2, and five strains carried LIPI-3 genes: one strain belonged to ST619 of lineage I, two strains belonged to ST224 of lineage I, and two strains belonged to ST11 of lineage II. (4) Conclusions: This study clarified the genotype and serotype characteristics of Listeria monocytogenes in Jiaxing, as well as their molecular characteristics relating to drug resistance and virulence, thus providing a technical basis for improving exposure risk assessment of Listeria monocytogenes. Continuous monitoring, prevention, and control are recommended to further improve regional public health and safety.

Klebsiella quasipneumoniae has emerged as a multidrug-resistant (MDR) pathogen of growing clinical concern, driven by its capacity to acquire mobile genetic elements encoding carbapenemases and novel resistance determinants. This study aimed to characterize the genomic architecture, resistance profile, and phenotypic impact of plasmids in a clinical K. quasipneumoniae strain co-producing blaNDM-1 and the tigecycline efflux pump gene cluster tmexCD2-toprJ2. Whole-genome sequencing and plasmid reconstruction were performed for strain KP10883 (KL159/ST1929). Antimicrobial susceptibility testing, plasmid curing, biofilm quantification, serum resistance assays, human lung epithelial cell infection assays, and Galleria mellonella infection models were used to evaluate the functional consequences of plasmid carriage. KP10883 harbored two functionally distinct plasmids: pKP10883-1, an IncU conjugative plasmid carrying blaNDM-1 and tmexCD2-toprJ2, conferring broad-spectrum antibiotic resistance, and pKP10883-2, a nonconjugative IncFIB/IncFII plasmid encoding stability and adaptation modules without classical resistance genes. Curing of pKP10883-1 resulted in complete loss of resistance to β-lactams, carbapenems, and tigecycline, confirming plasmid-mediated resistance. Paradoxically, plasmid loss led to increased biofilm formation, enhanced serum resistance, greater epithelial cell adhesion and cytotoxicity, and higher virulence in G. mellonella, indicating suppression of chromosomal virulence by plasmid-borne regulatory elements. This study reveals a plasmid-mediated trade-off between antimicrobial resistance and virulence in K. quasipneumoniae. The functional complementarity of pKP10883-1 and pKP10883-2 supports their stable coexistence and reflects a broader adaptive strategy balancing drug resistance with pathogenic potential. These findings underscore the importance of considering the regulatory impact of MDR plasmids on host virulence in developing strategies against emerging MDR pathogens.IMPORTANCEThe emergence of multidrug-resistant (MDR) Klebsiella quasipneumoniae poses an escalating threat to clinical treatment and infection control. This study provides the first comprehensive genomic and functional characterization of a clinical K. quasipneumoniae strain co-harboring blaNDM-1 and the tigecycline efflux pump cluster tmexCD2-toprJ2. By integrating genomic, phenotypic, and virulence analyses, we reveal a paradoxical trade-off in which plasmid acquisition confers extensive antibiotic resistance while suppressing host virulence. These findings uncover a novel plasmid-mediated regulatory mechanism balancing bacterial survival and pathogenicity. Understanding this interplay between resistance and virulence expands the current knowledge of MDR plasmid biology and provides valuable insights into how resistance evolution may reshape bacterial pathogenic potential-information critical for surveillance, therapeutic development, and containment of emerging high-risk Klebsiella lineages.

ABSTRACT This study aims to examine the differences in microbial community abundance and species distribution in the bronchoalveolar lavage fluid (BALF) obtained from non-cystic fibrosis bronchiectasis (NCFB) patients between those with and without Pseudomonas aeruginosa ( P. aeruginosa ) colonization, and to assess the impact of P. aeruginosa colonization on airway microecological imbalance in NCFB. Sixty-four patients were enrolled, grouped into P. aeruginosa -colonized (PA, 29) and non-colonized (NPA, 35) groups. Among patients with NCFB, those with P. aeruginosa colonization had greater disease severity than those without colonization, with significantly higher bronchiectasis severity index (BSI) scores ( P < 0.05). The proportions of patients with higher Bhalla and E-FACED scores were also greater in the PA group than in the NPA group (62.1% vs 42.8% and 34.1% vs 20%, respectively). Annual hospitalization frequency was numerically higher in PA (2.14 ± 2.43 vs 1.47 ± 0.86; P = 0.543). The PA group exhibited poorer pulmonary function, with significantly lower FEV1 and FEV1% predicted (both P < 0.01). In addition, NCFB patients in the PA group showed higher proportions of elevated white blood cell counts (31% vs 17.1%) and neutrophil percentages (41.4% vs 31.4%). Microbiota analysis of BALF demonstrated reduced alpha diversity in NCFB patients with P. aeruginosa colonization, with a predominance of Pseudomonas , whereas non-colonized NCFB patients had relatively higher abundances of Streptococcus , Acinetobacter , Rothia , Veillonella , and Prevotella . Overall, P. aeruginosa colonization in NCFB is associated with increased disease severity, heightened inflammation, and impaired lung function, accompanied by decreased microbial diversity, Pseudomonas dominance, and suppression of commensal taxa. IMPORTANCE Pseudomonas aeruginosa is a common colonizer in the airways of patients with non-cystic fibrosis bronchiectasis (NCFB), linked to disease severity, but research on its impact on clinical outcomes and airway microbiome diversity remains limited. This study compared P. aeruginosa -colonized (PA group) and non-colonized (NPA group) NCFB patients and found that the PA group had more severe disease (higher exacerbation, severity scores) and reduced bronchoalveolar lavage fluid (BALF) microbial α/β diversity (marked by Pseudomonas dominance and suppressed symbionts like Streptococcus ). These findings indicate that P. aeruginosa reshapes the microecology and is associated with airway microbial imbalance. This study confirms that P. aeruginosa colonization is a key factor in NCFB disease progression and airway microecological imbalance, highlighting reduced colonization and restored homeostasis as precision intervention strategies that inform targeted therapies.

Abstract Background The Enterobacter cloacae complex (ECC), a member of the genus Enterobacter within the family Enterobacteriaceae, is an important opportunistic pathogen associated with nosocomial infections. Colistin is considered a last-resort antimicrobial for multidrug-resistant Gram-negative infections; however, the emergence and dissemination of plasmid-mediated colistin resistance genes, particularly mcr variants, have raised significant public health concerns. Among these, mcr-10 has been increasingly detected in ECC isolates from diverse clinical and environmental sources, underscoring the importance of genomic surveillance to elucidate its genetic context and transmission potential. Methods Swab samples were collected from a kitchen sink and cultured for bacterial isolation, followed by species identification using MALDI-TOF MS. Antimicrobial susceptibility was determined by the broth microdilution method, with results interpreted according to EUCAST and CLSI guidelines. Whole-genome sequencing was performed using a hybrid approach combining Illumina short-read and Oxford Nanopore long-read sequencing. Genome annotation and antimicrobial resistance gene detection were conducted using RAST and ResFinder, respectively. Multilocus sequence typing and plasmid replicon typing were performed using the MLST and PlasmidFinder tools. Comparative plasmid analysis was carried out with EasyFig and BLAST Ring Image Generator, while phylogenetic relationships were inferred using a core-genome-based phylogenetic analysis, and the resulting tree was visualized with iTOL. Results Enterobacter kobei JX24083 was resistant to cefazolin, cefoxitin, and fosfomycin. Consistently, the isolate harbored the resistance genes bla ACT-9 and fosA on the chromosome. The colistin resistance gene mcr-10.1 was identified on an IncFIB plasmid in the isolate; however, the isolate remained susceptible to colistin (MIC = 1 mg/L). Exposure to subinhibitory concentrations of colistin upregulated mcr-10.1 expression in vitro. Comparative sequence analysis revealed a conserved xerC–mcr-10 genetic context among Enterobacter kobei isolates harboring plasmid-borne mcr-10. Phylogenetic analysis of JX24083 together with 46 mcr-10 -carrying ECC isolates from GenBank showed that several dominant sequence types, including ST681, ST125, and ST1, were distributed across different hosts and countries, indicating the potential for international dissemination. Conclusion The first report of an E. kobei isolate from a domestic kitchen sink in China carrying a conserved xerC–mcr-10 plasmid backbone, yet remaining susceptible to colistin, highlights the potential for silent dissemination of mcr-10 within the Enterobacter cloacae complex (ECC) and underscores the need for continuous One Health-oriented surveillance of environmental reservoirs.

Streptococcus suis is an emerging zoonotic pathogen that typically causes bacteremia or meningitis in humans, whereas vertebral osteomyelitis with epidural abscess is exceedingly rare and may be missed. We describe a 65-year-old farmer with fever and severe low back pain after long-term bare-handed handling of raw pig lungs. Pre-treatment blood cultures yielded S. suis identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). After transient improvement on empirical therapy, fever recurred with worsening lumbar pain. Contrast-enhanced magnetic resonance imaging (MRI) demonstrated multilevel thoracolumbar pyogenic spondylitis with an epidural abscess and a sub-ligamentous abscess beneath the posterior longitudinal ligament (PLL) extending from L2 to L5. Computed tomography-guided lumbar biopsy followed by tissue metagenomic next-generation sequencing (mNGS) detected S. suis, providing concordant evidence supporting pathogen involvement at the vertebral focus. The bloodstream isolate (SS-JX2025-01) was serotype 2, sequence type 7 (ST7). It remained susceptible to β-lactams and glycopeptides but was resistant to macrolide-lincosamide and tetracycline classes, consistent with erm(B), tet(O), tet(40), and ant(6)-Ia detected by whole-genome sequencing (WGS). Virulence profiling revealed an epf+/sly+/mrp- pattern with multiple adhesins and immune-evasion factors, whereas canonical 89K pathogenicity island markers were absent. Core-genome phylogeny placed SS-JX2025-01 within the Chinese ST7 lineage associated with previous outbreaks. This biopsy-supported case expands the clinical spectrum of invasive S. suis infection, highlights the value of tissue mNGS as an adjunct for supporting deep-seated foci in zoonotic infections, and underscores the importance of occupational prevention in small-scale farming households.

Background: Mycoplasma pneumoniae is a major respiratory pathogen. Accurate and timely diagnosis is critical for guiding treatment, as clinical symptoms overlap with those of other respiratory pathogens. Molecular assays, particularly fluorescent PCR, offer higher sensitivity and specificity but typically require time-consuming nucleic acid extraction steps, prolonging the detection process to over 1 hour. Objectives: This study aimed to develop a rapid and efficient method for direct sample analysis to overcome the limitations of conventional, time-consuming methods for M. pneumoniae detection. Methods: Primers and probe were designed based on conserved regions of the P1 gene. The specificity of primers and probe was verified by BLAST analysis. Assay conditions were optimized by adjusting primer/probe concentrations and two-stage annealing/extension parameters. Specificity was evaluated using 322 throat swab samples (including 32 M. pneumoniae-positive samples) collected from Jiaxing hospitals in 2024. Sensitivity was assessed by testing serial dilutions of M. pneumoniae positive control, with the detection limit calculated by probit analysis. Reproducibility was determined by intra- and inter-assay variability. The performance of the newly developed assay was compared with a commercial fluorescent PCR kit using 10-fold diluted M. pneumoniae-positive samples. Results: Melting curve analysis revealed that by 86°C, nearly all amplification products had completely denatured, which was used for denaturation in the second amplification stage. Optimal assay conditions included a primer concentration of 1 µM, a probe concentration of 0.6 µM, and annealing/extension conditions of 65°C for 10 s in the first stage and 60°C for 5 s in the second stage. The assay showed high specificity with no cross-reactivity to other respiratory pathogens. Sensitivity analysis indicated that the limit of detection of the assay in 95% of cases was 553.26 copies/mL (95% CI: 341.32 - 2063.47 copies/mL). The method demonstrated good reproducibility, with intra-assay variability of 1.86% and 3.17%, and inter-assay variability of 3.73% and 4.70% at 2500 and 1000 copies/mL, respectively. Head-to-head comparison using the same set of 10-fold diluted clinical samples demonstrated that the newly developed assay achieved a higher detection rate (62.5%, 20/32) than the commercial fluorescent PCR kit (53.1%, 17/32). Conclusions: The developed extraction-free fluorescent PCR offers a rapid, simple, and reliable approach for M. pneumoniae detection. It shows promise for clinical applications, particularly in outpatient settings requiring prompt diagnosis.

Introduction:Vibrio cholerae serogroups O1 and O139 are responsible for epidemic and pandemic cholera. Although the pathogenic potential and genomic diversity of V. cholerae strains have been extensively studied in endemic regions, limited genomic data are available for more developed regions such as Jiaxing. Methods:In this study, 15 V. cholerae O1 and O139 isolates (eight clinical and seven environmental) collected between 2021 and 2024 were analyzed. Antimicrobial susceptibility testing (AST) was performed, and whole-genome sequencing was conducted. Comparative genomic analyses were used to characterize antimicrobial resistance (AMR) determinants, virulence-associated genes, and population structure. Core genome multilocus sequence typing (cgMLST) was applied to assess genetic relatedness. Results:All strains were susceptible to ciprofloxacin, trimethoprim-sulfamethoxazole, tigecycline, and amikacin. Elevated MIC values were observed for colistin; however, no interpretive criteria are available for V. cholerae. By contrast, high resistance rates were observed for streptomycin, chloramphenicol, and azithromycin. Resistance genes, including qnr, tet, mph, and sul, were widely distributed, while bla genes were absent. One clinical O139 strain, VC0827, was found to harbor the ctxAB genes, a truncated CTX prophage, and an IncC plasmid (pVC0827), which carried several antimicrobial resistance genes including tet(A/B/M), flor, sul2, and msr(E). cgMLST analysis revealed three main clusters; VC0827 clustered closely with seventh-pandemic reference strains and shared sequence type ST69. The observed gene duplications (e.g., ace and zot) in VC0827 may enhance its toxigenic potential. Conclusion:This study highlights the genomic diversity and resistance profiles of V. cholerae in Jiaxing. The identification of a potentially virulent, multidrug-resistant O139 strain underscores the need for continuous genomic surveillance to monitor the emergence of toxigenic lineages and horizontal gene transfer.

BACKGROUND:Mucormycosis is a rare, rapidly progressive fungal infection caused by molds of the order Mucorales, most commonly Rhizopus species. While it predominantly affects immunocompromised patients, mediastinal mucormycosis is exceptionally rare, with fewer than 50 cases reported, and has a high mortality rate. Diagnosis is challenging owing to nonspecific clinical and radiologic findings, often mimicking malignancies such as lymphoma or thymoma. This study aims to report a rare case of primary mediastinal mucormycosis presenting with hoarseness and to highlight the diagnostic challenges and successful nonsurgical management. CASE PRESENTATION:We report a case of mediastinal mucormycosis in a 76-year-old mainland Chinese man with chronic obstructive pulmonary disease. His initial symptom was progressive hoarseness, likely due to recurrent laryngeal nerve involvement, a rare presentation for mediastinal mucormycosis. Contrast-enhanced chest computed tomography revealed a mass in the left hilar and upper mediastinal regions, suggestive of lung carcinoma. However, a computed tomography-guided mediastinal biopsy confirmed the presence of nonseptate, ribbon-like hyphae, consistent with mucormycosis. The patient was treated with intravenous amphotericin B followed by oral isavuconazole, resulting in marked lesion regression and symptomatic improvement after 6 months of antifungal therapy. In this case, surgery was not attempted because the infection was localized to the mediastinum, making surgical debridement technically unfeasible. CONCLUSION:Mediastinal mucormycosis, though rare, should be considered in patients with atypical presentations including hoarseness, particularly those with chronic illnesses. Early diagnosis through tissue biopsy and timely antifungal treatment is essential for better prognosis.

Proteus mirabilis is an opportunistic pathogen frequently associated with catheter-associated urinary tract infections (CAUTIs), where robust crystalline biofilms contribute to chronicity, antimicrobial tolerance, and recurrence. The rising prevalence of multidrug-resistant (MDR) P. mirabilis has prompted interest in bacteriophage therapy as an alternative to conventional antibiotics. In this study, we isolated a lytic bacteriophage, vB_PmiM_ZX7, from sewage using a highly virulent clinical strain, P. mirabilis YV2, as the host. vB_PmiM_ZX7 displayed a broad host range among MDR P. mirabilis isolates and tolerance to a wide range of pH and temperatures. Genome sequencing revealed 60% of genes with unknown function, absence of virulence or antibiotic resistance genes, and limited similarity to known P. mirabilis phages, underscoring its genomic novelty. Safety evaluation in a murine model showed no adverse effect, histopathological changes, or persistent phage accumulation. Circulating phages were cleared from the blood within 5 h and from organs within 48 h. In anti-biofilm assays, vB_PmiM_ZX7 eradicated 62.2% of established biofilms, outperforming piperacillin/tazobactam (TZP), and significantly reduced extracellular polysaccharide content and biofilm density, as confirmed by scanning electron microscopy and fluorescence imaging. Furthermore, vB_PmiM_ZX7 demonstrated strong anti-biofilm activity in an in vitro catheter-associated biofilm model, markedly reducing the viability of biofilm-associated bacteria in a time-dependent manner. These findings demonstrated the potential of vB_PmiM_ZX7 as a therapeutic candidate for catheter-associated MDR P. mirabilis infections.

Non-O1/non-O139 Vibrio cholerae strains are widely distributed in aquatic environments worldwide and are increasingly recognized as potential reservoirs of antimicrobial resistance and virulence-associated determinants. In this study, we performed an integrated phenotypic and genomic analysis of 116 V. cholerae isolates collected in 2024 from environmental and clinical sources in Jiaxing, China, including 106 non-O1/non-O139 isolates, 9 O1 isolates, and 1 O139 isolate. Antimicrobial susceptibility testing showed that most isolates remained susceptible to β-lactam/β-lactamase inhibitor combinations, third-generation cephalosporins, carbapenems, and tigecycline, whereas resistance was more frequently observed for ampicillin, streptomycin, nalidixic acid, and ciprofloxacin. Based on the non-susceptibility criteria of Maitrakas et al., 19 of 116 isolates (16.4%) were classified as multidrug-resistant, whereas none met the definition of extensively drug-resistant. Genomic analysis identified diverse resistance determinants, including plasmid-mediated quinolone resistance genes (qnrVC variants) and quinolone resistance-determining region mutations in gyrA and parC. Virulence-associated genes showed heterogeneous distributions: core regulatory and hemolysis-related genes were highly prevalent, whereas classical cholera toxin genes were largely absent. Several accessory virulence factors, including the RTX toxin operon, chxA, ninth, and makA, were detected in subsets of isolates. Core genome multilocus sequence typing revealed substantial genetic diversity, with environmental and clinical isolates distributed across multiple lineages and showing no clear clustering by isolation source. Overall, these data demonstrate the diverse antimicrobial resistance, virulence-associated gene repertoires, and population structure of the Jiaxing V. cholerae collection, with particular relevance to the predominant non-O1/non-O139 population.

BACKGROUND/OBJECTIVES:Multidrug-resistant Salmonella enterica serovar Enteritidis, especially those isolated from humans, remains a public concern. In the present study, S. Enteritidis strain 31404 was obtained clinically from a fecal sample of a fifteen-year-old girl, who was positive for blaNDM-13. METHODS:Antibiotic susceptibility testing and whole genome sequencing were performed. Core genome MLST and hierarchical clustering (HierCC) were performed using EnteroBase. Population structure analysis of 57 S. Enteritidis isolates collected between 2023 and 2025 in Jiaxing city was conducted. A comparative structure analysis of blaNDM-13-positive plasmids was also performed. RESULTS:S. Enteritidis strain 31404 was resistant to 13 antimicrobial agents. We found that strain 31404 belonged to ST11 and carried resistance genes, such as blaNDM-13, blaCTX-M-14, bleMBL, fosA3, qnrS, and tet (A). blaNDM-13 was located on an IncI1-I (α) plasmid designated as p31404-NDM13. S. Enteritidis isolate 31404 was closely related to PNUSAS514422, which was isolated from the United States in 2025. Comparative genetic environment related to blaNDM-13-positive plasmids available in the NCBI database indicates that ΔTn125-mediated contexts were commonly associated with blaNDM-13. IS1294 (IS91 family), which replaces ISAba125, is likely to mobilize blaNDM-13. CONCLUSIONS:The findings in this study provide insights into the molecular characterization and diversification of blaNDM-13. The identification of blaNDM-13-containing transferable plasmids in different serotypes of Salmonella isolates (such as S. Rissen, S. Typhimurium, and S. Enteritidis) in different cities in China highlights the risk of the spread of carbapenem-resistant genes among Salmonella isolates.

Bacteria are emerging as a promising tool for targeted cancer therapy due to their innate tumor-homing ability, high mobility, and capacity to rapidly colonize in the tumor microenvironment (TME). However, bacterial cancer therapy (BCT) alone has not proven fully effective. Herein, we present an innovative bio-therapeutic system, TEPy@VNP-D, which integrates genetically engineered Salmonella typhimurium VNP20009 carrying humanized DNase I toxin plasmids (VNP-D) with an aggregation-induced emission photosensitizer (TEPy), enabling photoimmunotherapy for melanoma. Leveraging the tumor-targeting properties of VNP20009, TEPy@VNP-D ensures effective delivery of both TEPy and DNase I to tumor sites, promoting the intratumoral accumulation of cytotoxic agents. Upon light activation, TEPy@VNP-D not only disrupts bacterial structures, facilitating plasmid release but also directly kills cancer cells through the generation of cytotoxic reactive oxygen species. Accordingly, the synergistic effects of photodynamic therapy (PDT) from TEPy and tumor lysis by VNP-D result in significant tumor suppression. Furthermore, TEPy@VNP-D enhances both innate and adaptive immune responses by triggering immunogenic cell death and remodeling the immunosuppressive TME. When combined with anti-PD-L1 antibody, TEPy@VNP-D elicits remarkable synergistic effects under light irradiation, effectively eliminating distant abscopal tumors and establishing robust immune memory to prevent recurrence and rechallenge. Together, the TEPy@VNP-D-mediated BCT synergized photoimmunotherapy strategy offers a powerful, tailored approach to cancer treatment, achieving cooperative antitumor activity with reduced toxicity. This promising approach holds great potential for advancing combination cancer therapies.

Acute cholangitis is a potentially life-threatening condition commonly caused by bacterial infections of the biliary tract. Here, we present an unusual case of acute cholangitis caused by Vibrio cholerae in a 76-year-old man with a history of hypertension, diabetes, asthma, and post-cholecystectomy who presented with upper abdominal pain, jaundice, and fatigue. Lab results showed elevated inflammatory markers and bilirubin. Imaging revealed gallstones and bile duct dilation. Blood cultures isolated non-toxigenic Vibrio cholerae, which was highly susceptible to all tested antibiotics. The patient was successfully treated with piperacillin/tazobactam and levofloxacin, along with supportive care. His symptoms resolved, and subsequent cultures were negative. This case highlights a rare instance of non-cholera Vibrio cholerae causing acute cholangitis and bacteremia in an elderly patient.

Background Lung abscess is a severe pulmonary infection usually caused by anaerobic or pyogenic bacteria. Mycoplasma pneumoniae (MP), a common cause of community-acquired pneumonia, is only rarely implicated in lung abscess formation. Available reports of MP-associated lung abscess have been largely confined to pediatric patients, and adult cases have not been clearly documented to date. Case presentation We report a 74-year-old male with chronic obstructive pulmonary disease (COPD) who presented with chest pain, productive cough, and dyspnea. Chest CT revealed a cavitary lesion with an air-fluid level in the right lower lobe. Despite broad-spectrum antibiotics, the lesion progressed. Conventional cultures were negative, but targeted next-generation sequencing (tNGS) of bronchoalveolar lavage fluid identified 29,507 sequence reads of MP, confirming the diagnosis of MP-associated lung abscess. Antimicrobial therapy was switched to levofloxacin, leading to clinical improvement and marked radiological resolution. Conclusion This case represents a rare presentation of lung abscess associated with Mycoplasma pneumoniae infection in an adult patient, with COPD likely serving as a predisposing factor. It highlights the importance of considering MP in cases of culture-negative lung abscess with atypical clinical features and underscores the value of targeted molecular diagnostics, such as tNGS, in guiding appropriate antimicrobial therapy and improving clinical outcomes

IntroductionSalmonella is an important foodborne pathogen that can induce severe diseases such as gastrointestinal disease and typhoid fever. Accumulating evidence revealed that Salmonella’s resistance to antibiotics also seriously affects human health. Pathogenic Salmonella enterica serovar Goldcoast (S. Goldcoast) was first detected in 2010 in China and was predicted to have an increasing tendency.MethodsThe MacConkey agar, Salmonella Shigella agar, three-sugar iron agar slant, and Gram-stained microscopic examination were used for strain identification. Gram-negative bacteria identification cards explored more properties of the isolates, while antimicrobial susceptibility testing was used to examine the multidrug resistance. The 2nd and 3rd generation sequencing revealed the genetic information of the isolates.ResultsTwo non-pathogenic isolates with multidrug resistance, JS33 and JS34, harbored 42 antibiotic-resistant genes (ARGs) in contig1 and 13 ARGs in contig2, were isolated from a healthy donor living in southeast China and identified as S. Goldcoast (6,8:r:l,w). Interestingly, JS33 and JS34 showed identical responses to more than 20 antimicrobial agents and were resistant to ampicillin, selectrin, chloramphenicol, tetracycline, and streptomycin. However, JS33 differed from JS34 in hydrogen sulfide (H2S) generation. The genomic sequencing identified a deletion in thiosulfate reductase (K08352) in JS34.DiscussionH2S is an essential physiological regulator linked to inflammation and cancer. Therefore, genomic identification of JS33 and JS34 provided us with a better understanding of drug resistance and could be used as model strains to study the effects of microbial H2S production on the host. Since JS33 and JS34 did not induce gastrointestinal infection or other clinical symptoms as previously reported, the appearance of non-pathogenic S. Goldcoast in southeast China warned us to prepare for the prevalence of antimicrobial-resistant S. Goldcoast in China.