Rapid and ultrasensitive detection of pathogen-associated biomarkers is vital for the early diagnosis and therapy of bacterial infections. Herein, we developed a close-packed and ordered Au@AgPt array coupled with a cascade triggering strategy for surface-enhanced Raman scattering (SERS) and colorimetric identification of the Staphylococcus aureus biomarker micrococcal nuclease (MNase) in serum samples. The trimetallic Au@AgPt nanozymes can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) molecules to SERS-enhanced oxidized TMB (oxTMB), accompanied by the color change from colorless to blue. In the presence of S. aureus, the secreted MNase preferentially cut the nucleobase AT-rich regions of DNA sequences on magnetic beads (MBs) to release alkaline phosphatase (ALP), which subsequently mediated the oxTMB reduction for inducing the colorimetric/SERS signal fade away. Using this "on-to-off" triggering strategy, the target S. aureus can be recorded in a wide linear range with a limit of detection of 38 CFU/mL in the colorimetric mode and 6 CFU/mL in the SERS mode. Meanwhile, the MNase-mediated strategy characterized by high specificity and sensitivity successfully discriminated between patients with sepsis (n = 7) and healthy participants (n = 3), as well as monitored the prognostic progression of the disease (n = 2). Overall, benefiting from highly active and dense "hot spot" substrate, MNase-mediated cascade response strategy, and colorimetric/SERS dual-signal output, this methodology will offer a promising avenue for the early diagnosis of S. aureus infection.

Objective:To identify and trace the origin of the Francisella tularensis subsp. novicida strain SJCS-979 isolated from the blood of a patient, so as to provide a reference for the traceability investigation of such infection events. Methods:Hot spring water samples that the patient had recently bathed in were collected to culture the causative agent, combined with the pathogenic characteristics and the patient′s activity before the bloodstream infection. The water samples were concentrated, acid-treated, and then the isolation of the causative agent was performed, following the method for Legionella detection in circulating cooling water. Suspected strains detected from the hot spring water were subjected to classical phenotypic identification, API ZYM and API NH strips tests, drug sensitivity testing, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification, and the obtained data were compared with those of strain SJCS-979 isolated from the patient′s blood. A phylogenetic tree was constructed based on genomic analysis to determine the taxonomic status of strain SJCS-979 and related strains. Epidemiological data of Francisella tularensis subsp. novicida were collected and analyzed by integrating the global genetic and genomic data on GenBank database. Core single nucleotide polymorphism(SNP) comparisons were obtained using Snippy 3.2 software, and then an evolutionary tree was built to determine its population structure based on BAPS analysis. Results:Strain CC-2, isolated from the hot spring water, shared the same biochemical and drug sensitivity phenotype, and had a nearly consistent mass spectrometric profile with strain SJCS-979 isolated from the blood of a patient. Genomic phylogenetic tree analysis based on 120 core protein sequences showed that strains SJCS-979 and CC-2 fell on the same branch with known Francisella tularensis subsp. novicida strains. Bayesian genotyping showed that the global Francisella tularensis subsp. novicida strains with genomic data could be divided into six different sequence clusters. Strains SJCS-979 and CC-2 were located in the same taxonomic group with only 4 SNP differences, indicating that they might be the same clone. Conclusions:This study reports a case of bacteremia caused by Francisella tularensis subsp. novicida, and natural hot spring water may be the environmental source of this infection event.

Rapid and ultrasensitive detection of pathogen-associated biomarkers is vital for the early diagnosis and therapy of bacterial infections.Herein,we developed a close-packed and ordered Au@AgPt array coupled with a cascade triggering strategy for surface-enhanced Raman scattering(SERS)and colorimetric identification of the Staphylococcus aureus biomarker micrococcal nuclease(MNase)in serum samples.The trimetallic Au@AgPt nanozymes can catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine(TMB)molecules to SERS-enhanced oxidized TMB(oxTMB),accompanied by the color change from colorless to blue.In the presence of S.aureus,the secreted MNase preferentially cut the nucleobase AT-rich regions of DNA sequences on magnetic beads(MBs)to release alkaline phosphatase(ALP),which subsequently mediated the oxTMB reduction for inducing the colorimetric/SERS signal fade away.Using this"on-to-off"triggering strategy,the target S.aureus can be recorded in a wide linear range with a limit of detection of 38 CFU/mL in the colorimetric mode and 6 CFU/mL in the SERS mode.Meanwhile,the MNase-mediated strategy characterized by high specificity and sensitivity successfully discriminated between patients with sepsis(n=7)and healthy participants(n=3),as well as monitored the prog-nostic progression of the disease(n=2).Overall,benefiting from highly active and dense"hot spot"substrate,MNase-mediated cascade response strategy,and colorimetric/SERS dual-signal output,this methodology will offer a promising avenue for the early diagnosis of S.aureus infection.

Objective:To identify and trace the origin of the Francisella tularensis subsp. novicida strain SJCS-979 isolated from the blood of a patient, so as to provide a reference for the traceability investigation of such infection events. Methods:Hot spring water samples that the patient had recently bathed in were collected to culture the causative agent, combined with the pathogenic characteristics and the patient′s activity before the bloodstream infection. The water samples were concentrated, acid-treated, and then the isolation of the causative agent was performed, following the method for Legionella detection in circulating cooling water. Suspected strains detected from the hot spring water were subjected to classical phenotypic identification, API ZYM and API NH strips tests, drug sensitivity testing, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) identification, and the obtained data were compared with those of strain SJCS-979 isolated from the patient′s blood. A phylogenetic tree was constructed based on genomic analysis to determine the taxonomic status of strain SJCS-979 and related strains. Epidemiological data of Francisella tularensis subsp. novicida were collected and analyzed by integrating the global genetic and genomic data on GenBank database. Core single nucleotide polymorphism(SNP) comparisons were obtained using Snippy 3.2 software, and then an evolutionary tree was built to determine its population structure based on BAPS analysis. Results:Strain CC-2, isolated from the hot spring water, shared the same biochemical and drug sensitivity phenotype, and had a nearly consistent mass spectrometric profile with strain SJCS-979 isolated from the blood of a patient. Genomic phylogenetic tree analysis based on 120 core protein sequences showed that strains SJCS-979 and CC-2 fell on the same branch with known Francisella tularensis subsp. novicida strains. Bayesian genotyping showed that the global Francisella tularensis subsp. novicida strains with genomic data could be divided into six different sequence clusters. Strains SJCS-979 and CC-2 were located in the same taxonomic group with only 4 SNP differences, indicating that they might be the same clone. Conclusions:This study reports a case of bacteremia caused by Francisella tularensis subsp. novicida, and natural hot spring water may be the environmental source of this infection event.

Objective:To analyze the clinical characteristics of dengue fever patients, summarize the course and characteristics of the disease, and analyze the risk factors that affect the condition.Methods:Retrospective collection of general information, clinical symptoms, medical history, laboratory tests, prognosis and other clinical data of dengue fever patients that admitted to Jinghong First People's Hospital and severe dengue fever patients at People's Hospital of Xishuangbanna Dai Autonomous Prefecture from June to December 2023 was conducted using a case report form (CRF). According to the diagnostic criteria of the World Health Organization (WHO), patients were divided into dengue fever group, dengue fever with warning signs group, and severe dengue fever group. The differences in clinical data between different groups of patients were analyzed and compared. Binary multiple factor Logistic regression analysis was used to explore the risk factors affecting the severity of dengue fever in patients. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of prediction models constructed for various risk factors for severe dengue fever. Subgroup analysis was performed on the prognosis of severe dengue fever patients, and the differences in clinical data between two groups of patients with different prognoses were compared. Binary multivariate Logistic regression analysis was used to explore the risk factors affecting the prognosis of severe dengue fever patients. ROC curve was drawn to analyze the predictive value of prediction models constructed for various risk factors on the prognosis of severe dengue fever patients.Results:A total of 2 264 patients were included, including 499 cases in the dengue fever group, 1 379 cases in the dengue fever with warning signs group, and 386 in the severe dengue fever group (43 deaths and 343 survivors). The most common symptom of dengue fever patients was fever (94.70%), followed by muscle soreness (70.54%), headache (63.12%), fatigue (58.92%), and chills (46.02%). Compared with the dengue fever group and the dengue fever with warning signs group, the ratio of thalassemia and the levels of cardiac troponin (cTnI, cTnT), MB isoenzyme of creatine kinase (CK-MB), and myoglobin were significantly increased in patients with severe dengue fever group, albumin (Alb) was significantly decreased in patients with severe dengue fever group. The levels of cTnT and myoglobin in patients with dengue fever with warning signs group were significantly higher than those in the dengue fever group, and the level of Alb in patients with dengue fever with warning signs group was significantly lower than that in the dengue fever group, the differences were statistically significant (all P < 0.05). Binary multivariate Logistic regression analysis showed that thalassemia [odds ratio ( OR) = 6.214, 95% confidence interval (95% CI) was 2.337-16.524, P < 0.001], Alb ≤ 36 g/L ( OR = 6.297, 95% CI was 4.270-9.286, P < 0.001), and cTnT levels ( OR = 1.008, 95% CI was 1.002-1.015, P = 0.016) were risk factors for severe dengue fever. ROC curve analysis showed that the area under the ROC curve (AUC) for predicting severe dengue fever based on the prediction models constructed for the above risk factors was 0.856, with the best predictive value of 0.067, sensitivity of 67.1%, and specificity of 99.4%. In the subgroup analysis of patients with severe dengue fever, compared with the survival group, the levels of hematocrit (HCT), cTnT, and CK-MB in the death group patients were significantly increased, while the level of Alb was significantly decreased, and the differences were statistically significant. Binary multivariate Logistic regression analysis showed that Alb ( OR = 0.839, 95% CI was 0.755-0.932, P = 0.001), HCT ( OR = 1.086, 95% CI was 1.010-1.168, P = 0.025), elevated troponin level ( OR = 10.119, 95% CI was 2.596-39.440, P < 0.001), and CK-MB ( OR = 1.081, 95% CI was 1.032-1.133, P < 0.001) were risk factors for mortality in patients with severe dengue fever. ROC curve analysis showed that the AUC for predicting death in severe dengue fever patients based on the prediction models constructed for the above risk factors was 0.881, with the best predictive value of 0.113, sensitivity of 75.0%, and specificity of 88.9%. Conclusion:Thalassemia, Alb≤36 g/L, and cTnT level are risk factors for severe dengue fever, while HCT level, Alb level, CK-MB level, and elevated troponin level are risk factors for death in patients with severe dengue fever.

Objective:To construct an evaluation system for clinical thinking ability of general practitioners in the treatment of multimorbidity.Methods:This was a cross-sectional study. The draft of evaluation indexes for clinical thinking ability of general practitioners in treatment of multimorbidity was preliminary developed through literature review, collation, analysis and discussion. Nineteen clinical and teaching experts of general practice were selected for consultation via anonymous convenient sampling. From January to June 2022, 2 rounds of expert consultation were conducted using the Delphi method. During the first round of consultation, according to the survey feedback, we modified and improved the evaluation system of general practitioners′ clinical thinking ability for multi-disease co-treatment. During the second round, experts were asked to assess the importance of each index, and to calculate the weight of each index accordingly. Questionnaires were sent to experts via letters. The content of the questionnaires encompasses the basic information of experts, evaluation for various indexes and relevant opinions. The mean value of importance assignment ≥3.5, coefficient of variation ≤0.25 and the full score frequency ≥30% were taken as the criteria. Indexes unsatisfying the criteria were removed, so that the final index system could be constructed.Results:The average age of 19 experts was 50.2 years old, 9 of them were male. A total of 2 rounds of expert consultation were conducted, 19 questionnaires were issued in each round, and 19 effective questionnaires were received afterwards. In the first round of consultation, 10 experts put forward revised opinions, and some indexes were adjusted according to the definition criteria and the discussion of the research group. In the second round of consultation, 3 experts put forward suggestions for modification. According to the definition criteria, no need to delete the indexes. After discussion by the research group, some indexes were adjusted, and finally an evaluation system of clinical thinking ability for multi-disease co-treatment of general practitioners was established, including 4 first-level indexes and 30 second-level indexes. The weights of the 4 first-level indexes in descending order were "overall thinking ability" (38.01%), "diagnostic thinking ability" (33.96%), "evidence-based thinking ability" (14.75%), and "critical thinking ability" (13.28%). Among the 30 secondary indexes, the top 5 were "ability to identify and handle priority emergency incidents" (5.04%), "risk assessment and critical illness identification ability" (4.63%), "emergency referral ability" (4.61%), "communication and expression ability" (4.57%), and "standardized diagnosis and treatment ability" (4.23%).Conclusion:This study successfully constructed an evaluation system for clinical thinking ability of general practitioners in the treatment of multimorbidity.

[This corrects the article DOI: 10.1016/j.apsb.2022.08.024.].

Objective:To identify and characterize one Spiroplasma strain (designated as DGKH1) isolated from the blood of a patient with sepsis. Methods:The traditional bacterial culture, staining, morphological observation, physiological and biochemical identification, 16S rRNA gene sequencing, phylogenetic analysis, genome sequencing, and the genome-related index analysis were performed to accurately determine the taxonomic status of the strain DGKH1. Antibiotic susceptibility testing was performed using a specific kit for culturing and testing Ureaplasma urealyticum/ Metamycoplasma hominis. Results:The strain DGKH1 could weakly grow on Columbia blood agar, chocolate agar, and Haemophilus chocolate 2 agar. However, it did not grow in liquid culture medium containing tetracycline (4 μg/ml), doxycycline (1 μg/ml), minocycline (1 μg/ml), josamycin (2 μg/ml), roxithromycin (1 μg/ml), clarithromycin (1 μg/ml), or telithromycin (1 μg/ml). DGKH1 resembling Metamycoplasma hominis formed "fried egg-like colonies" on Mycoplasma solid culture medium. DGKH1 could not be stained by Gram staining. When observed under transmission electron microscopy (TEM) using phosphate buffer as the matrix, the bacteria were spiral-shaped. Results of 16S rRNA gene sequence alignment showed that DGKH1 was highly similar (99.85%) to Spiroplasma eriocheiris CCTCC M 207170 T. However, the urea decomposition test was positive, which was different from all of the known Spiroplasma species. The phylogenetic analysis based on whole genome showed that DGKH1 was clustered in a small branch along with Spiroplasma eriocheiris CCTCC M 207170 T. However, the average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between the two strains were 94.14% and 56.00%, respectively, both below the threshold for prokaryotic species identification. Conclusions:DGKH1 represented a potential new species of genus Spiroplasma, closely related to Spiroplasma eriocheiris. Some microbiological characteristics of DGKH1 were similar to Mycoplasmas. However, the natural host and epidemiological data of DGKH1 need to be further studied.

Objective:To identify and characterize two Balneatrix alpica strains isolated from a patient′s blood sample (strain X117) and the natural hot spring water in the patient′s residential district (strain GN-1), and to provide experimental evidence for the pathogenic diagnosis of clinical infection caused by this rare pathogen. Methods:Biochemical phenotypic identification, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA gene sequencing, phylogenetic analysis, single-nucleotide polymorphism (SNP) analysis, and genome-wide analysis were performed to accurately determine the taxonomic status of the isolates X117 and GN-1 by using Balneatrix alpica DSM 16621 T as a reference. Microdilution broth method was used to test their antimicrobial susceptibility. The virulence genes carried by them were annotated and analyzed using the virulence factor database (VFDB). Results:Strains X117 and GN-1 formed light yellow or tan colonies with mottled surfaces on Columbia blood agar and chocolate agar plates after 4 d of culture. They were Gram-negative rods and positive for oxidase and indole tests, which were consistent with the characteristics of Balneatrix alpica DSM 16621 T. The phylogenetic analysis based on the 16S rRNA gene showed that the isolates X117 and GN-1 were both Balneatrix alpaca. The average nucleotide identity (ANI) values between the two isolates and Balneatrix alpica DSM 16621 T were 98.44% and 98.41%, respectively, and the digital DNA-DNA hybridization (dDDH) values were both 87.1%. The SNP distance between the two strains was 13, indicating that X117 and GN-1 might belong to the same clone. The antibiotic susceptibility testing showed that all of the three Balneatrix alpica strains were sensitive to the commonly used antibiotics against Gram-negative rods. The virulence genes carried by the three Balneatrix alpica strains were mainly involved in adhesion, invasion, flagella and biofilm formation. Conclusions:This study identified a case of bloodstream infection caused by Balneatrix alpica which was closely related to natural hot spring water. Natural hot spring water migh be an important source of clinical infections caused by this species.

Objective:To study the molecular phylogeny and virulence gene profile of Francisella salimarina. Methods:Phylogenetic analysis of Francisella salimarina was performed based on the global genome data of related Francisella species on GenBank database. The consistency in phylogenetic analysis based on single marker genes (such as 16S rRNA gene, rpoB gene and mdh gene) and the core genome as compared. Virulence genes and antibiotic resistance genes were annotated using the virulence factor database (VFDB) and the Comprehensive Antibiotic Resistance Database (CARD), respectively. The virulence of Francisella salimarina was analyzed with a Galleria mellonella (greater wax moth) infection model using Francisella philomiragia ATCC 25015 T as reference strain. Results:The phylogenetic analysis revealed that Francisella salimarina was closely related to Francisella philomiragia. The phylogenetic tree based on mdh gene was highly similar to that based on the core genome. Francisella salimarina could be differentiated from other related species by 16S rRNA gene or mdh gene, with the latter being more accurate. Eight Francisella salimarina strains carried multiple virulence genes, mainly involved in secretion, adhesion, immune regulation, motility and stress survival. Moreover, beta-lactam resistance gene blaFPH was identified in all eight strains. Francisella salimarina showed high lethality in the Galleria mellonella infection model, which was similar to Francisella philomiragia ATCC 25015 T. Conclusions:Francisella salimarina was a rare pathogen with similar pathogenicity to Francisella philomiragia. The mdh gene could be used as a molecular target for rapid identification of Francisella salimarina.