1.Microbiological characterization of Staphylococcus epidermidis with hemolytic phenotype
Guiyun LENG ; Wei CHEN ; Chenghao WANG ; Jie YAO ; Chuanping CHEN ; Wei TANG
Acta Universitatis Medicinalis Anhui 2026;61(1):60-66
ObjectiveTo explore the microbiological characteristics of Staphylococcus epidermidis with hemolytic phenotype (SEHP). MethodsHemolytic phenotype was detected using the three-point inoculation method, involving a total of 5 strains of SEHP and 5 strains of Staphylococcus epidermidis with non-hemolytic phenotype (SENHP) . Bacterial species were identified using the Microflex LT MALDI-TOF mass spectrometer, and a phylogenetic tree was constructed through 16S rRNA sequence alignment. Growth curves were monitored through the microcultivation assay. Biofilm formation ability was assessed by microplate crystal violet staining. Red blood cell toxicity was detected using the microplate method. Antimicrobial susceptibility testing of SEHP and SENHP against commonly used antibiotics was performed using a VITEK 2 GP639 test kit. Antagonistic effects of SEHP and SENHP against Staphylococcus aureus and Corynebacterium striatum were evaluated by the Oxford cup inhibition assay. ResultsCompared with SENHP, SEHP exhibited a marked decrease in growth rate during the late logarithmic phase, accompanied by significant hemolytic toxicity. Additionally, it showed lower resistance rates to levofloxacin and moxifloxacin, and could antagonize Staphylococcus aureus and Corynebacterium striatum. ConclusionThe microbiological characteristics of SEHP differ from those of SENHP in that SEHP demonstrates antagonistic effects against S. aureus and C. striatum.
2.Feasibility study of a domestic fully automated NAT system for blood screening in blood donors
Fenglan YAO ; Rui WANG ; Jinghui HU ; Hongwei GE ; Chan LENG ; Yi ZHA ; Zifu ZHAO ; Zhengmin LIU
Chinese Journal of Blood Transfusion 2025;38(7):941-949
Objective: To validate the analytical performance, operational performance, and process control measures of a domestic fully automatic nucleic acid testing (NAT) system, thereby ensuring an efficient and orderly blood screening workflow. Methods: The concordance rate and sensitivity of WanTag-Vortex Plus system were verified using WHO standard reference panels of HIV-1, HCV and HBV, while precision was assessed using weak positive samples of HIV-1, HCV and HBV. As for its operational performance evaluation, cross-contamination resistance was assessed using strong positive samples, and throughput and stress testing were conducted using negative samples. Reagent stability was verified using weak positive samples, and inter-system performance consistency was assessed using verification panels. In addition, the process control measures were verified using the laboratory quality control demand scale. Results: 1) Verification of concordance rate: The detection results of negative and positive samples of HIV-1, HCV and HBV by WanTag-Vortex Plus system were all consistent with expectations, and the concordance rate was 100%. 2) Precision verification: the repeatability and intermediate precision were extremely high, and the coefficient of variation was less than 5%. 3) Verification of analytical sensitivity: The detection limit of 95% for standard strains of HIV-1, HCV and HBV by WanTag-Vortex Plus system in our laboratory was consistent with the analytical sensitivity provided by reagent manufacturers. 4) Verification of cross-contamination resistance: Five strong positive samples and 87 negative samples were placed according to the actual working conditions and equipment operation design, and the test results were consistent with expectations, with no cross-contamination in the testing system. 5) Throughput and stress testing: Each system completed the individual donor-nucleic acid amplification testing (ID-NAT) of 276 samples in three batches within 12 hours, and successfully completed the ID-NAT test of 828 samples in three consecutive days. 6) Verification of reagent stability: After extreme storage (unsealed storage for 1 week with 4 freeze-thaw cycles), the reagents maintained 100% detection rate in the weak positive samples of HIV-1, HCV, and HBV, showing no significant differences from the control group (Kappa=1). 7) Verification of inter-system performance consistency: The system has stable operation performance, and the performance comparison results across the four devices were consistent (Kappa=1). 8) Process control measures: WanTag-Vortex Plus system software accurately controlled the equipment operation process with strict quality control measures, and correctly interpreted and safely reported the test results. Conclusion: The analytical and operational performance of the WanTag-Vortex Plus system complies with manufacturer design standards and essential laboratory workflow requirements. Integrated with laboratory information system (LIS), the system's control software meets standard process control requirements, yet requires further improvement.
3.Feasibility study of a domestic fully automated NAT system for blood screening in blood donors
Fenglan YAO ; Rui WANG ; Jinghui HU ; Hongwei GE ; Chan LENG ; Yi ZHA ; Zifu ZHAO ; Zhengmin LIU
Chinese Journal of Blood Transfusion 2025;38(7):941-949
Objective: To validate the analytical performance, operational performance, and process control measures of a domestic fully automatic nucleic acid testing (NAT) system, thereby ensuring an efficient and orderly blood screening workflow. Methods: The concordance rate and sensitivity of WanTag-Vortex Plus system were verified using WHO standard reference panels of HIV-1, HCV and HBV, while precision was assessed using weak positive samples of HIV-1, HCV and HBV. As for its operational performance evaluation, cross-contamination resistance was assessed using strong positive samples, and throughput and stress testing were conducted using negative samples. Reagent stability was verified using weak positive samples, and inter-system performance consistency was assessed using verification panels. In addition, the process control measures were verified using the laboratory quality control demand scale. Results: 1) Verification of concordance rate: The detection results of negative and positive samples of HIV-1, HCV and HBV by WanTag-Vortex Plus system were all consistent with expectations, and the concordance rate was 100%. 2) Precision verification: the repeatability and intermediate precision were extremely high, and the coefficient of variation was less than 5%. 3) Verification of analytical sensitivity: The detection limit of 95% for standard strains of HIV-1, HCV and HBV by WanTag-Vortex Plus system in our laboratory was consistent with the analytical sensitivity provided by reagent manufacturers. 4) Verification of cross-contamination resistance: Five strong positive samples and 87 negative samples were placed according to the actual working conditions and equipment operation design, and the test results were consistent with expectations, with no cross-contamination in the testing system. 5) Throughput and stress testing: Each system completed the individual donor-nucleic acid amplification testing (ID-NAT) of 276 samples in three batches within 12 hours, and successfully completed the ID-NAT test of 828 samples in three consecutive days. 6) Verification of reagent stability: After extreme storage (unsealed storage for 1 week with 4 freeze-thaw cycles), the reagents maintained 100% detection rate in the weak positive samples of HIV-1, HCV, and HBV, showing no significant differences from the control group (Kappa=1). 7) Verification of inter-system performance consistency: The system has stable operation performance, and the performance comparison results across the four devices were consistent (Kappa=1). 8) Process control measures: WanTag-Vortex Plus system software accurately controlled the equipment operation process with strict quality control measures, and correctly interpreted and safely reported the test results. Conclusion: The analytical and operational performance of the WanTag-Vortex Plus system complies with manufacturer design standards and essential laboratory workflow requirements. Integrated with laboratory information system (LIS), the system's control software meets standard process control requirements, yet requires further improvement.
4.Study on the antagonistic activity of Lactococcus garvieae SHAMU-LG6 against Staphylococcus
Shengnan Weng ; Guiyun Leng ; Ying Liu ; Yawu Wang ; Xin Li ; Jie Yao ; Qiang Zhou ; Wei Tang
Acta Universitatis Medicinalis Anhui 2025;60(2):195-200
Objective :
To investigate the antagonistic activity of Lactococcus garvieae SHAMU-LG6 against Staphy- lococcus .
Methods :
VITEK 2 GP identification card , Microflex LT MALDI-TOF mass spectrometer and 16S rDNA amplification sequencing were used to identify the strain species . The antagonistic activity of L. garvieae SHAMU- LG6 against different Staphylococcus was detected by Oxford cup method for bacterial inhibition ; the antimicrobial active components were preliminarily isolated and purified by adsorption on XAD16 nonionic macroporous resin , gradient ethanol elution and rotary evaporation drying.
Results :
L. garvieae SHAMU-LG6 exhibited potent antago- nistic effect against methicillin-resistant Staphylococcus aureus , methicillin-susceptible S. aureus , S. epidermidis , S. saprophyticus , S. lugdunensis , S. hominis , S. capitis and S. warneri , with inhibitory indices of 3 . 3 , 3 . 0 , 4. 3 , 2. 0 , 4. 0 , 3 . 5 , 3 . 8 , and 3 . 5 , respectively. The antimicrobial active components produced by L. garvieae SHAMU-LG6 were mainly present in 70% and 80% ethanol eluates .
Conclusion
L. garvieae SHAMU-LG6 ex- hibits a potent antagonistic effect on Staphylococcus , and the antimicrobial active components produced by it are ex- pected to be a lead compound for the development of novel antimicrobial agents .
5.Whole genome sequencing analysis of four strains of CAMP negative Streptococcus agalactiae
Xiu Wang ; Jie Yao ; Guiyun Leng ; Wei Tang ; Qiang Zhou
Acta Universitatis Medicinalis Anhui 2025;60(4):707-711
Objective :
To explore the molecular characteristics of four CAMP negativeStreptococcus agalactiae(S.agalactiae) in whole genome sequencing.
Methods :
The identification of suspicious bacterial strains was conducted using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS). For the strains confirmed asS.agalactiaethrough identification, further CAMP experiments were conducted. For CAMP negative strains, whole genome sequencing was performed using MGI DNBSEQ-T7 and MinION Flow Cell sequencing platforms. Subsequently, multi-locus sequence typing(MLST), virulence genes and resistance genes of the strains were compared and analyzed using various databases. Phoenix M50 fully automatic drug sensitivity analyzer was employed to determine the sensitivity of the bacterial strains to commonly used antibiotics.
Results:
Four CAMP-negativeS.agalactiaestrains were included. Whole-genome sequencing analysis revealed that all four CAMP-negativeS.agalactiaestrains belonged to the ST862 type. These strains harbored 22 virulence genes associated with capsular polysaccharides, β-hemolysin, and hyaluronidase, as well as seven resistance genes linked to macrolides, lincosamides, polypeptides, and aminoglycosides. Antimicrobial susceptibility testing revealed that CAMP-negativeS.agalactiaewas susceptible to penicillin G, cefepime, cefotaxime, and vancomycin. However, three strains exhibited resistance to erythromycin, and one strain demonstrated resistance to clindamycin.
Conclusion
Four CAMP negativeS.agalactiaeof the ST862 type possess multiple virulence and drug resistance genes, showing high resistance to erythromycin, warranting clinical attention.
6.Complete cfb gene deletion in Streptococcus agalactiae: molecular mechanism of qPCR false negatives
Xiu Wang ; Guiyun Leng ; Yunsi Yang ; Wei Tang ; Qiang Zhou ; Jie Yao
Acta Universitatis Medicinalis Anhui 2025;60(9):1624-1630
Objective :
To investigate the causes of false negative results in the detection of Streptococcus agalactiae using fluorescent quantitative PCR(qPCR) targeting the CAMP factor gene(cfb),and to perform a comprehensive analysis of the associated molecular mechanisms.
Methods:
A total of 76 vaginal secretion samples were evaluated using both qPCR based on cfb gene and bacterial culture methods. Four suspicious strains exhibiting negative qPCR results but positive culture findings were identified using matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS),latex agglutination antigen detection,and the CAMP test. Whole genome analysis was conducted utilizing the MGI DNBSEQ-T7 and Nanopore-PromethION 48 sequencing platforms. Phylogenetic and circular evolutionary trees were constructed using the 16S rRNA gene for strain verification. Multilocus sequence typing(MLST) was conducted,and cfb sequences were aligned and analyzed based on spliced sequences and original data. Specific primers targeting the cfb gene were designed for full-length amplification,followed by verification through agarose gel electrophoresis.
Results:
The four strains identified as suspicious were classified as S. agalactiae through MALDI-TOF MS,antigen detection,and 16S rRNA gene analysis,with MLST typing indicating ST-862. Phenotypic analysis revealed a negative CAMP test. Whole genome sequence alignment failed to detect the cfb gene or any homologous sequences,and molecular testing confirmed the absence of cfb gene PCR amplification products,thereby confirming its complete deletion.
Conclusion
This deletion is identified as the molecular mechanism responsible for the false negative qPCR detection of S. agalactiae when targeting this specific gene.It is recommended that the qPCR detection targeting a single cfb gene has limitation,and this may impact clinical diagnosis and treatment decisions. This limitation warrants carefulconsideration.
7.Hemolytic phenotype analysis of Staphylococcus aureus clinical isolates
Ju Gao ; Shengnan Weng ; Guiyun Leng ; Xin Li ; Jie Yao ; Qiang Zhou ; Wei Tang
Acta Universitatis Medicinalis Anhui 2025;60(7):1312-1319
Objective:
To investigate the hemolytic phenotypes of Staphylococcus aureus clinical isolates.
Methods:
The hemolytic phenotypes of 105 Staphylococcus aureus isolates were analyzed and summarized using the three-point inoculation method.Real-time fluorescence quantitative PCR was used to measure the mRNA expression levels of four hemolysin genes (hla,hlb,hlc,and hld) ; The VITEK 2 GP639 antimicrobial susceptibility card was used to detect resistance to commonly used antibiotics ; DNA gel electrophoresis was performed to determine the prevalence of the mecA,sea,tst,and pvl genes ; The microtiter plate crystal violet staining method was used to assess biofilm formation ability ; The CCK-8 assay was used to evaluate cytotoxicity against macrophages.
Results:
Seven hemo- lytic phenotypes were identified among the Staphylococcus aureus clinical isolates. Differences were found among Staphylococcus aureus clinical isolates with different hemolytic phenotypes in terms of mRNA expression levels of he- molysin genes,antibiotic resistance,virulence gene prevalence,biofilm formation ability,and cytotoxicity to mouse macrophages (P <0. 05 ) .
Conclusion
Staphylococcus aureus clinical isolates exhibit diverse hemolytic pheno- types,which should be a focus across multiple dimensions,including microbiological testing,clinical treatment, and nosocomial infection prevention and control.
8.Mechanism of aggravated severity in hypertriglyceridemia-associated acute pancreatitis:insights from the pathogenesis of"fat-turbidity-toxic heat"
Yuying LI ; Xinmin YANG ; Shaoqi ZHONG ; Yulin LENG ; Linbo YAO ; Tingting LIU ; Tao JIN ; Qing XIA ; Wei HUANG
Journal of Beijing University of Traditional Chinese Medicine 2024;47(5):672-678
Hypertriglyceridemia-associated acute pancreatitis is an inflammatory disorder of exocrine pancreas caused by metabolism disturbances of triglyceride-rich lipoproteins.Currently,hypertriglyceridemia-associated acute pancreatitis is characterized by an escalating incidence rate,a tendency for more severe cases,and a lack of therapeutic drugs.Traditional Chinese medicine has distinct advantages in treating this disease,but its theoretical framework has not yet been established.Hypertriglyceridemia-associated acute pancreatitis manifests itself as a febrile disease,aberrant accumulation of fat and turbidity may stem from dietary imbalances and visceral dysfunction in ordinary individuals.The prolonged accumulation of fat and turbidity can transform into turbid pathogen,subsequently engendering heat,constituting a pivotal pathogenic factor.Throughout the progression of the disease,the fiery pathogen consumes the fat and turbidity,resulting in the generation of toxic heat,which is a crucial mechanism in the exacerbation of the disease severity.Thus,this article posits therapeutic principles aimed at averting the transformation of fat and turbidity into turbid pathogen and counteracting toxic heat in this disease.This article reviews two key theories from traditional Chinese medicine classics relevant to hypertriglyceridemia-associated acute pancreatitis:the theory of fat-turbidity associated with hypertriglyceridemia and the febrile disease related to acute pancreatitis.Combining these traditional theories with modern research on the mechanisms that intensify hypertriglyceridemia-associated acute pancreatitis and the corresponding targets of traditional Chinese medicine,it suggests that the pathogenesis of"fat-turbidity-toxic heat"serves as the theoretical basis of traditional Chinese medicine for the aggravated severity of hypertriglyceridemia-associated acute pancreatitis.The article aims to offer new insights for the treatment of hypertriglyceridemia-associated acute pancreatitis.
9.Characterization of Staphylococcus aureus strains with novel incomplete hemolytic phenotype
Wei TANG ; Guiyun LENG ; Ju GAO ; Yawu WANG ; Jie YAO ; Qiang ZHOU ; Yuanhong XU
Acta Universitatis Medicinalis Anhui 2024;59(9):1535-1542
Objective To explore the microbiological characteristics of Staphylococcus aureus(S.aureus)with no-vel incomplete hemolytic phenotype(SIHP).Methods Hemolytic phenotypes were detected and categorized by u-sing the three-point inoculation method.A total of 11 novel SIHP and 33 randomly matched S.aureus with com-plete hemolytic phenotype(SCHP)were included.Antibiotic susceptibility test was performed using broth microdi-lution method.Coagulase test was performed with freeze-dried rabbit plasma.Catalase activity was detected by slide catalase test.Expression of hemolysin genes was detected by qRT-PCR.Toxicity to human red blood cells was as-sessed by microplate method.Microplate biofilm formation was measured using crystal violet staining method.Growth kinetic determination was performed through microcultivation assay.Results Compared with SCHP,the expression profiles of the four hemolysin genes(hla,hlb,hlc,and hld)in the new SIHP were different.The new SIHP had higher resistance rates to penicillin,oxacillin,gentamicin,quinolones,clindamycin,and trimethoprim-sulfamethoxazole.Furthermore,the new SIHP had stronger hemolytic toxicity,plasma coagulase activity,and bio-film formation ability.Additionally,the new SIHP grown faster in the logarithmic phase.Conclusion Taken to-gether,the microbiological characteristics of the new SIHP are different from those of SCHP,including stronger an-tibiotic resistance and pathogenicity,which should be paid more attention by clinicians.
10.Research progress of radiation nephropathy
Lin DENG ; Shaoqing WANG ; Xingli LENG ; Peng YAO ; Cuicui LI
Chinese Journal of Radiological Medicine and Protection 2023;43(4):314-320
Radiotherapy is an important treatment for malignant tumors. However, it is also one cause of damage to local normal tissues, such as radiation nephropathy, which is frequently induced during the radiotherapy of abdominal and pelvic tumors. The exact pathogenesis of radiation nephropathy is still unclear and is believed to be related mainly to factors including oxidative stress, cell aging, and gene changes presently. Moreover, there is a lack of effective treatments for radiation nephropathy. With an increase in the survival of tumor patients, radiation nephropathy has received increasing attention. This article mainly reviewed the research progress of radiation nephropathy from the aspects of pathogenesis and treatments, aiming to provide a reference for the research and clinical diagnosis and treatment of radiation nephropathy.


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