Xingbei Weng

Introduction: Aeromonas spp. are increasingly recognized opportunistic pathogens of humans, yet integrated genomic and phenotypic data from clinical, extra-intestinal isolates remain limited. We characterized 74 non-duplicate Aeromonas isolates recovered from extra-intestinal clinical specimens at a tertiary hospital in Ningbo, China, between 2020 and 2025, combining whole-genome sequencing (WGS)-based taxonomy, antimicrobial susceptibility testing, and resistome and putative virulence factor (VF) prediction. Methods: Species were identified by average nucleotide identity (ANI) analysis and sequence types (STs) by multilocus sequence typing (MLST). Susceptibility to 11 agents was interpreted according to the Clinical and Laboratory Standards Institute (CLSI) guideline M45. Resistance genes were predicted against the Comprehensive Antibiotic Resistance Database (CARD) and VFs against the Virulence Factors of Pathogenic Bacteria database (VFDB); genotype–phenotype concordance was quantified with Cohen’s κ, and VF profiles were analyzed by principal coordinates analysis and permutational multivariate analysis of variance (PERMANOVA). Results: Six species were identified, dominated by Aeromonas caviae (32.4%), Aeromonas veronii (25.7%) and Aeromonas dhakensis (24.3%). Bile was the leading source of isolation (51.4%), and species were significantly associated with isolation site (Fisher’s exact test, p < 0.001). The population was genetically diverse (71 STs, 39 novel). Resistance was highest to piperacillin/tazobactam (29.7%), whereas only one isolate was resistant to amikacin. Eighty-five resistance genes were detected, with a ubiquitous intrinsic β-lactamase background ( OXA-12-like , cphA/imiH and MOX-type genes in 63.5, 58.1 and 41.9% of isolates, respectively) and the acquired carbapenemase gene bla _NDM-1 in three isolates. Genotype–phenotype agreement was substantial for trimethoprim/sulfamethoxazole (κ = 0.773–0.856) and fluoroquinolones ( κ = 0.706) but poor for β-lactams. Fifty-six VFs were detected, comprising a conserved 26-VF core virulome and accessory determinants structured by species (PERMANOVA R ² = 0.797, p = 0.001). A. dhakensis and A. hydrophila carried the heaviest VF loads and were enriched for aerolysin, ExoA, MARTX/RtxA and T6SS, whereas A. caviae lacked aerolysin and had the sparsest virulome. Discussion: Species identity was the dominant correlate of clinical distribution and virulence potential, supporting genome-based species identification as the basis for risk assessment of clinical Aeromonas isolates.

Background: Superficial fungal infections (SFIs) are among the most common skin diseases worldwide; however, the pathogenic species of SFIs vary among geographical areas. The purpose of this study was to evaluate the epidemiologic profile of superficial fungal infections with a focus on onychomycosis in the Department of Laboratory Medicine of Ningbo First Hospital. Methods: A total of 1309 patients with superficial mycoses who visited our hospital between March 2023 and October 2024 were selected. Scraping of the lesion was performed via a sterilization scraper. A portion of each sample was used for direct examination, and the other portion was used for cultivation. For the culture results, microscopic morphology and automatic rapid microbial matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used as a routine examination. For fungi that routine examinations couldn’t identify, further sequencing of the rDNA-ITS region was carried out for atypical strains to the species level. Results: Patients were between 1 year and 93 years old, and the peak incidence was in the 21–30 years age group. More superficial mycoses were found in women (63.94%) than in men (36.06%). The causative agents identified were: dermatophytes (32.85%), yeasts (49.20%) and non-dermatophyte molds (NDM) (17.95%). Positive cultures of dermatophytes were obtained from 430 patients: Trichophyton spp. (89.07%) was predominant, followed by Microsporum spp. (10.93%). Yeasts were isolated from 644 patients, and Candida spp. (93.01%) were the major pathogens, followed by Trichosporon spp. (6.99%). Among the 1309 patients, nails were the largest source of SFIs (81.67%), followed by glabrous skin (6.04%) and feet (4.20%). Candida spp. were the most prevalent species in cases of onychomycosis (47.05%), followed by Trichophyton spp. (29.09%) and Aspergillus spp. (16.65%). Conclusion: Our study revealed that nails constituted the largest source of SFIs in Ningbo, and women were more likely to have onychomycosis than men were. Moreover, we found that Candida spp. was the most prevalent species in cases of onychomycosis, and Trichophyton rubrum was responsible for the majority of dermatophyte-associated infections.

Purpose: Carbapenem-resistant Klebsiella pneumoniae (CRKP) is linked to hospital-acquired infections and associated with significant mortality rates, presenting a serious risk to public health. This research aimed to examine the in-hospital epidemiology and antimicrobial resistance of CRKP isolates, offering insights for the management and control of CRKP infections. Patients and Methods: In total, 76 carbapenem-resistant Klebsiella pneumoniae isolates were collected from inpatients at the First Affiliated Hospital of Ningbo University from May 2022 and February 2024. The isolates were mainly acquired from sputum, urine, secretions, and blood. Antimicrobial susceptibility testing was performed using the VITEK 2 Compact system or the Kirby-Bauer disk-diffusion method. In addition to susceptibility testing, phylogenetic analysis, and serotype analysis, whole genome sequencing was conducted to identify genes associated with antibiotic resistance. Results: Antimicrobial susceptibility testing showed that all 76 CRKP isolates were resistant to most common antibiotics. The CRKP isolates mainly carried Klebsiella pneumoniae carbapenemase, and the predominant gene was bla_KPC-2. Homology analysis found that the major sequence type (ST) was ST11, as a single isolate was identified as an ST11 single-locus variant (ST6853), followed by ST15 and ST48. Serotype analysis found that the major serotype was K64, followed by K24 and K62. Conclusion: The CRKP isolates in our study exhibited resistance to the majority of commonly used antibiotics. The bla_KPC-2 gene was identified as the predominant carbapenemase. The major ST of CRKP found in our hospital was ST11, with K64 and O2a being the prevalent predicted serotypes. These findings should prove useful for the control and management of CRKP infections, and provided guidance for clinical antibiotic therapy.

This report presents the case of false-negative cerebral spinal fluid (CSF) cryptococcal antigen (CrAg) lateral flow assay (LFA) in a HIV-positive 25-year-old male. The patient presented with headache, nausea and vomiting for 5 days and syncope for 1 day. An initial CSF CrAg LFA test was negative, but a 1:4 dilution of the CSF was weakly positive and a 1:8 dilution was positive. A serum cryptococcal antigen test was weakly positive. Cultures of blood and CSF were all positive for Cryptococcus neoformans. The explanation for the false-negative CSF CrAg LFA test is that the antigen concentration was too high causing the postzone phenomenon.

Background: Talaromyces marneffei (T. marneffei) is a temperature‐dependent dimorphic fungus that is mainly prevalent in Southeast Asia and South China and often causes disseminated life‐threatening infections. This study aimed to investigate the clinical features and improve the early diagnosis of talaromycosis marneffei in nonendemic areas.Methods: We retrospectively analyzed the medical records of six cases of T. marneffei infection. We describe the clinical manifestations, laboratory tests, and imaging manifestations of the six patients.Results: Talaromyces marneffei infection was confirmed by sputum culture, blood culture, tissue biopsy, and metagenomic next‐generation sequencing (mNGS). In this study, there were five disseminated‐type patients and two HIV patients. One patient died within 24 h, and the others demonstrated considerable improvement after definitive diagnosis.Conclusions: Due to the lack of significant clinical presentations of talaromycosis marneffei, many cases may be easily misdiagnosed in nonendemic areas. It is particularly important to analyze the imaging manifestations and laboratory findings of infected patients. With the rapid development of molecular biology, mNGS may be a rapid and effective diagnostic method.

Although uncommon, infection caused by Clostridium subterminale may be life threatening particularly in immunocompromised patients. We report here a rare presentation of a patient with diffuse large B-cell lymphoma and haemophagocytic syndrome associated with C. subterminale bacteraemia. The management of the patient is described as well as a review of medical literature. Infection by Clostridium species, including C. subterminale, should be considered in a febrile patient with a haematologic malignancy. The case highlights the importance of using gene sequencing for identification of this anaerobic organism.

Objective. This study aimed to investigate the efficacy of the colloidal gold immunochromatography method in the detection of Cryptococcus antigen in bronchoalveolar lavage fluid (BALF) for pulmonary cryptococcosis (PC) diagnosis. Methods. A total of 111 patients with clinically suspected PC who were finally diagnosed with nonhuman immunodeficiency virus infection and hospitalized in the Ningbo First Hospital from March 2017 to December 2021 were retrospectively analyzed. All the confirmed cases were divided into two groups as follows: the PC group (33 cases) and the non-PC group (78 cases). All the patients were subjected to serum and BALF cryptococcal capsular polysaccharide antigen-lateral flow immunochromatographic assay (CrAg-LFA) and etiological culturing. Results. In the PC group, serum CrAg-LFA was positive for 24 and negative for 9 cases, serum Cryptococcus culture was positive for 1 and negative for 32 cases, BALF CrAg-LFA was positive for 31 and negative for 2 cases, and BALF Cryptococcus culture was positive for 9 and negative for 24 cases. In the non-PC group, serum CrAg-LFA was positive for 1 and negative for 77 cases, serum culture was negative in all the cases, and both BALF CrAg-LFA and culture were negative in all the cases. The sensitivity, specificity, and accuracy of BALF CrAg-LFA for PC diagnosis were 93.9%, 100%, and 98.2%, respectively, whereas those of BALF culture were 27.3%, 100%, and 78.4%, respectively. The sensitivity and accuracy of BALF CrAg-LFA were higher than that of serum CrAg-LFA and BALF etiological culture with statistically significant differences ( ). Conclusion. The diagnostic value of BALF CrAg-LFA for PC is superior to that of serum CrAg-LFA and BALF etiological culture.

Purpose: To investigate clinical characteristics of six cases of Eikenella corrodens infection in Ningbo First Hospital in China in recent 2 years.Methods: We retrospectively analyze medical records of six cases of E. corrodens infection in Ningbo First Hospital from 2020 to 2021. And we describe the gender, age, clinical manifestations, antimicrobial administration, and treatment of the six patients.Results: Five of the patients had deep infection and they were treated with surgical drainage or abscess resection plus antimicrobial administration. After treatment, five patients were discharged and recovered well, and another patient was transferred to another hospital for further treatment. All the six cases were in line with the reports on the clinical characteristics of patients infected with E. corrodens at home and abroad before 2021.Conclusion: Eikenella corrodens is a part of the normal flora of human oropharynx, but it can migrate to other parts of the human body to cause severe invasive disease in humans. Although it is susceptible to most antimicrobials, it needs debridement in the treatment of deep infection.

Background: The aim was to investigate the distribution of antibiotic resistance determinants and virulence factors in a group of carbapenem non-susceptible Pseudomonas aeruginosa (P. aeruginosa). Methods: From March 2018 to May 2019, a total of 98 P. aeruginosa samples were collected from 6 hospitals in Ningbo and Hangzhou, Zhejiang Province, China. Drug susceptibility tests to 13 antimicrobial agents were conducted. The presence of antibiotic resistance determinants and virulence factors were investigated by PCR, including 39 beta-lactamase genes, 14 aminoglycoside modifying enzyme genes, 10 16SrRNA methylase genes, and 11 virulence genes. Phylogenetics of 98 P. aeruginosa was analyzed by sample cluster analysis (UPGMA). Results: PCR revealed the presence of 7 beta-lactamase genes, 5 aminoglycoside modifying enzymes, 1 16S rRNA methylase gene, and 8 virulence genes in total, at least 2 beta-lactamase genes and 4 virulence genes were positive in every isolate. In addition, regional differences in distributions of resistance and virulence genes remained between 2 cities. Sample cluster analysis showed that the strains had obvious aggregation and were divided into several clusters, strains in the same cluster were isolated from different hospitals, even from different cities. Conclusions: Carrying resistance genes blaPDC and blaOXA-50 group and virulence genes plcH, aprA, and algD were the important epidemiological characteristics of this group of P. aeruginosa. The present findings provide insights into the mechanisms of hypervirulence as well as resistance to beta-lactams and aminoglycosides. To the best of our knowledge, this is the first report of blaPDC, blaOXA-50, and aph(3')-XV in P. aeruginosa in China.