1.Curcumin extraction and preparation and optimization of curcumin nanoparticles
Yuhang WANG ; Han ZHANG ; Chaojing ZHANG ; Xurong KOU ; Tongtong JING ; Rimei LIN ; Xinyu LIU ; Shilei LOU ; Hui YAN ; Cong SUN
Chinese Journal of Tissue Engineering Research 2026;30(2):362-374
BACKGROUND:Curcumin is the main active ingredient of turmeric and has significant medicinal value in anti-tumor,anti-inflammatory,antioxidant and other aspects.However,its poor water solubility,unstable chemical properties and easy decomposition lead to difficulty in extracting curcumin and low extraction yield.Therefore,it is particularly important to optimize the curcumin extraction method.OBJECTIVE:To enhance the extraction yield and utilization value of curcumin and optimize the curcumin extraction process and curcumin nanoparticle preparation process.METHODS:Curcumin was extracted from turmeric by ethanol extraction,ultrasonic extraction,ionic liquid extraction,enzyme extraction,and ionic liquid combined with ultrasonic assisted enzyme extraction.The curcumin extraction yield was detected by high performance liquid chromatography;the best extraction method was determined,and subsequent process optimization experiments were carried out.The curcumin extraction yield was the response value with the type of ionic liquid,reaction temperature,ultrasonic time,liquid-to-solid ratio,ionic liquid concentration,and enzyme-drug mass ratio as parameters.The optimal production process of ionic liquid combined with ultrasonic assisted enzyme extraction was determined by single factor combined response surface experiment.The optimal process for preparing curcumin nanoparticles by ionic crosslinking method was determined by single factor combined response surface experiment with acetic acid concentration,chitosan to sodium tripolyphosphate mass ratio,stirring rate,curcumin mass concentration,sodium tripolyphosphate mass concentration,and chitosan mass concentration as parameters,and drug encapsulation efficiency as response value.Curcumin nanoparticles were prepared under the optimal process,and the particle size,polydispersity index,Zata potential value,drug loading,stability,hemolysis rate,and antioxidant capacity in vivo and in vitro of the nanoparticles were detected.RESULTS AND CONCLUSION:(1)Among the five extraction methods,the curcumin yield of ionic liquid combined with ultrasound-assisted enzyme extraction was the highest,and this method was selected as the curcumin extraction method for subsequent experiments.The results of single factor combined response surface experiment showed that the optimal process for curcumin extraction was:ionic liquid selected 1-hexyl-3-methylimidazolium chloride,reaction temperature 55 ℃,liquid-to-solid ratio 40 mL/g,ultrasound time 57 minutes,ionic liquid concentration 57%,enzyme-drug mass ratio 3.5:10,and the obtained turmeric extraction yield was 3.10%.The optimal preparation process of curcumin nanoparticles was:glacial acetic acid concentration 0.5%,chitosan and sodium tripolyphosphate mass ratio 5.0:1,stirring speed 150 r/min,curcumin mass concentration 2.23 mg/mL,sodium tripolyphosphate mass concentration 1.45 mg/mL,chitosan mass concentration 3.63 mg/mL,and the obtained drug encapsulation efficiency was 90.61%.(2)The drug loading of curcumin nanoparticles was(14.49±0.23)%,the average particle size was(76.95±1.65)nm,the polydispersity coefficient was 0.15±0.02,and the Zata potential value was(32.37±1.46)mV.The curcumin nanoparticles had good stability and blood compatibility,did not induce hemolysis,and had stronger antioxidant capacity in vivo and in vitro than free curcumin.(3)The results show that the process optimization not only solves the problems of low extraction yield,poor solubility,and low bioavailability of curcumin,but also enhances its antioxidant activity in vivo and in vitro.
2.Curcumin extraction and preparation and optimization of curcumin nanoparticles
Yuhang WANG ; Han ZHANG ; Chaojing ZHANG ; Xurong KOU ; Tongtong JING ; Rimei LIN ; Xinyu LIU ; Shilei LOU ; Hui YAN ; Cong SUN
Chinese Journal of Tissue Engineering Research 2026;30(2):362-374
BACKGROUND:Curcumin is the main active ingredient of turmeric and has significant medicinal value in anti-tumor,anti-inflammatory,antioxidant and other aspects.However,its poor water solubility,unstable chemical properties and easy decomposition lead to difficulty in extracting curcumin and low extraction yield.Therefore,it is particularly important to optimize the curcumin extraction method.OBJECTIVE:To enhance the extraction yield and utilization value of curcumin and optimize the curcumin extraction process and curcumin nanoparticle preparation process.METHODS:Curcumin was extracted from turmeric by ethanol extraction,ultrasonic extraction,ionic liquid extraction,enzyme extraction,and ionic liquid combined with ultrasonic assisted enzyme extraction.The curcumin extraction yield was detected by high performance liquid chromatography;the best extraction method was determined,and subsequent process optimization experiments were carried out.The curcumin extraction yield was the response value with the type of ionic liquid,reaction temperature,ultrasonic time,liquid-to-solid ratio,ionic liquid concentration,and enzyme-drug mass ratio as parameters.The optimal production process of ionic liquid combined with ultrasonic assisted enzyme extraction was determined by single factor combined response surface experiment.The optimal process for preparing curcumin nanoparticles by ionic crosslinking method was determined by single factor combined response surface experiment with acetic acid concentration,chitosan to sodium tripolyphosphate mass ratio,stirring rate,curcumin mass concentration,sodium tripolyphosphate mass concentration,and chitosan mass concentration as parameters,and drug encapsulation efficiency as response value.Curcumin nanoparticles were prepared under the optimal process,and the particle size,polydispersity index,Zata potential value,drug loading,stability,hemolysis rate,and antioxidant capacity in vivo and in vitro of the nanoparticles were detected.RESULTS AND CONCLUSION:(1)Among the five extraction methods,the curcumin yield of ionic liquid combined with ultrasound-assisted enzyme extraction was the highest,and this method was selected as the curcumin extraction method for subsequent experiments.The results of single factor combined response surface experiment showed that the optimal process for curcumin extraction was:ionic liquid selected 1-hexyl-3-methylimidazolium chloride,reaction temperature 55 ℃,liquid-to-solid ratio 40 mL/g,ultrasound time 57 minutes,ionic liquid concentration 57%,enzyme-drug mass ratio 3.5:10,and the obtained turmeric extraction yield was 3.10%.The optimal preparation process of curcumin nanoparticles was:glacial acetic acid concentration 0.5%,chitosan and sodium tripolyphosphate mass ratio 5.0:1,stirring speed 150 r/min,curcumin mass concentration 2.23 mg/mL,sodium tripolyphosphate mass concentration 1.45 mg/mL,chitosan mass concentration 3.63 mg/mL,and the obtained drug encapsulation efficiency was 90.61%.(2)The drug loading of curcumin nanoparticles was(14.49±0.23)%,the average particle size was(76.95±1.65)nm,the polydispersity coefficient was 0.15±0.02,and the Zata potential value was(32.37±1.46)mV.The curcumin nanoparticles had good stability and blood compatibility,did not induce hemolysis,and had stronger antioxidant capacity in vivo and in vitro than free curcumin.(3)The results show that the process optimization not only solves the problems of low extraction yield,poor solubility,and low bioavailability of curcumin,but also enhances its antioxidant activity in vivo and in vitro.
3.Screening and biological characteristics of bacteriophage HN_Aba_01 against multidrug-resistant Acinetobacter baumannii
Hanwang ZHOU ; Lin CONG ; Mei YU ; Huihui KUANG ; Yue ZHANG ; Hongyan HU
Chinese Journal of Nosocomiology 2025;35(20):3089-3094
OBJECTIVE To analyze the biological characteristics and genomic features of highly lytic bacteriopha-ges isolated from sewage in tropical hospitals and provide references for the hospital-associated infection prevention and control of multidrug-resistant Acinetobacter baumannii(MDR-Ab).METHODS With MDR-Ab as the host bacterium,bacteriophages were isolated from sewage.Transmission electron microscopy was employed to observe their morphology,and determine the optimal multiplicity of infection(MOI),one-step growth curve and environ-mental stability.Whole-genome sequencing and bioinformatics analysis were conducted to annotate functional genes and construct a phylogenetic tree.RESULTS A virulent bacteriophage,HN_Aba_01,was isolated.Elec-tron microscopy revealed that it belonged to the Myoviridae family,with a head diameter of 50 nm and a tail length of 90 nm.This bacteriophage exhibited strong lytic activity,with an optimal MOI of 0.000 000 1,a latent period of 5 minutes and a lysis yield of 15 PFU/cell.It remained stable at temperatures ranging from 4 ℃ to 60 ℃and pH values from 3 to 10.Genomic analysis identified 85 ORFs,including lyase,perforin and depolymerase genes.It shared 98.12%identity with the bacteriophage AbP2 genome(reference genome)and was classified into the Obolenskvirus genus.CONCLUSIONS The bacteriophage isolated from tropical hospital sewage,with high lyt-ic activity and good environmental adaptability,can be used for the hospital-associated infection prevention and control of MDR-Ab.
4.Identification and cluster analysis of non-O1/O139 Vibrio cholerae by MALDI-TOF MS
Maosuo XU ; Hui ZHANG ; Cong ZHOU ; Chunmei SHEN ; Yong LIN
Chinese Journal of Clinical Laboratory Science 2025;43(3):161-166
Objective To identify and cluster non-O1/O139 Vibrio cholerae(NOVC)using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS),and evaluate the feasibility of MALDI-TOF MS as a method for the identification and clustering of NOVC.Methods The NOVC was identified by the MALDI-TOF MS equipped with V5 database,V12 database,highly pathogenic bacteria database,and V5 database combined with self-built spectrum projection and analyzed by the principal com-ponent analysis(PCA)and main spectrum projection(MSP)clustering.Results The NOVC was incorrectly identified as Vibrio al-bensis by the MALDI-TOF MS equipped with V5 database or V12 database,while the MALDI-TOF MS equipped with highly pathogenic bacteria database or V5 database combined with self-built spectrum projection could correctly identify NOVC.The PCA clustering of MALDI-TOF MS could distinguish NOVC from other bacterial strains and refine the differentiation of NOVC species to show the dis-tance relationship between NOVC species.Some spectrum projections of NOVC were extremely similar to the reference strains used to establish the database,and MSP clustering could not distinguish the differences between NOVC species.Conclusion The identifica-tion ability of MALDI-TOF MS for NOVC is limited by its database.The MALDI-TOF MS equipped with highly pathogenic bacteria da-tabase or V5 database combined with the self-built spectrum projection can accurately identify NOVC.The PCA clustering of MALDI-TOF MS has certain reference significance for the intra-and inter-species identification and homology analysis of NOVC.
5.Effect of joint management of type 2 diabetes mellitus between specialty department and community health under National Diabetes Prevention and Control Center (DPCC) model
Ying HUANG ; Yi QIAN ; Xuchi WU ; Zhongyu ZHOU ; Cong WANG ; Lin WANG ; Caiyan HUANG ; Zhuangsen CHEN ; Yanrong ZHANG ; Shanshan WANG ; Lu WANG ; Jie WAN ; Ruihong YANG ; Huiya WANG ; Yan CHEN ; Cheng HE ; Kun FENG ; Dewen YAN
Journal of Chinese Physician 2025;27(3):338-342
Objective:To analyze the effect of joint management of type 2 diabetes mellitus (T2DM) between specialty and community under the model of National Diabetes Prevention and Control Center (DPCC).Methods:A total of 2 527 T2DM patients managed by DPCC Pingshan Center of Shenzhen from January 1, 2022 to December 31, 2024 were retrospectively included. After management, the rate of downturn, reexamination rate, blood pressure compliance rate, metabolic indicators (waist circumference, body mass index, fasting blood glucose, glycosylated hemoglobin, blood lipids) and screening rate of chronic complications of diabetes (atherosclerotic cardiovascular disease, microvascular disease, diabetic peripheral neuropathy) were analyzed. Those included 2022 ( n=564), 2023 ( n=1 477), and 2024 ( n=2 527). Results:The downturn rate in 2022, 2023 and 2024 increased year by year (22.8% vs 67.2% vs 89.9%, P<0.01), and the review rate (41.1% vs 62.2% vs 52.7%, P<0.01), complication screening rate (51.6% vs 85.3% vs 62.2%, P<0.01), blood pressure compliance rate (53.1% vs 78.0% vs 67.2%, P<0.01), body mass index compliance rate (13.2% vs 17.3% vs 28.6%, P<0.01), fasting blood glucose meeting rate (46.4% vs 60.2% vs 68.5%, P<0.01), glycated hemoglobin meeting rate (58.4% vs 63.2% vs 45.6%, P<0.01) were relatively improved. Waist circumference compliance rate (30.6% vs 27.7% vs 21.6%) and blood lipid compliance rate (33.6% vs 35.5% vs 31.9%) were not significantly improved, and the review rate, blood pressure compliance rate and complication screening rate in 2024 were lower than those in 2023 and higher than those in 2022. Conclusions:The combined management of type 2 diabetes under the DPCC model has significant effects on improving the down-conversion rate, rediagnosis rate, blood pressure compliance rate, metabolic index compliance rate and the screening rate of diabetes-related chronic complications in patients with diabetes. At the same time, it was also found that with the progress of hierarchical diagnosis and treatment, the review rate, complication screening rate, blood pressure, waist circumference, blood lipid and glycosylated hemoglobin reached the standard of patients decreased compared with the previous situation, which needs to be further analyzed and improved.
6.Clinical characteristics analysis of chronic obstructive pulmonary disease patients with comorbid fatigue
Tao LI ; Qing SONG ; Ling LIN ; Cong LIU ; Ping ZHANG ; Yuqin ZENG ; Ping CHEN
Journal of Chinese Physician 2025;27(6):804-808
Objective:To analyze the clinical characteristics of patients with chronic obstructive pulmonary disease (COPD) complicated by fatigue.Methods:COPD patients enrolled in the RealDTC study from June 2023 to March 2024 were included. Demographic data, history of acute exacerbations in the past year, smoking status, biofuel exposure, occupational exposure, modified Medical Research Council (mMRC) dyspnea score, COPD Assessment Test (CAT) score, forced expiratory volume in the first second predicted of percentage (FEV 1%pred), forced expiratory volume in one second (FEV 1)/forced vital capacity (FVC), and comorbidities (bronchial asthma, bronchiectasis, tuberculosis, cardiovascular disease, diabetes mellitus) were collected. Fatigue was evaluated using the Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) questionnaire, with a score ≤43 defined as fatigue. Patients were divided into fatigue and non-fatigue groups, and multivariate regression analysis was used to screen factors associated with fatigue in COPD patients. Results:A total of 597 COPD patients were included, of which 280(46.9%) had fatigue symptoms. Compared with non-fatigue patients, fatigue patients had lower FEV 1%pred, FEV 1/FVC, and body mass index (BMI), higher CAT and mMRC scores, and a higher proportion of occupational exposure, bronchiectasis, and treatment with long-acting β 2-agonists (LABA)/long-acting muscarinic antagonists (LAMA)/inhaled corticosteroids (ICS) (all P<0.05). Multivariate regression analysis showed that high CAT score ( OR=2.312, 95% CI: 1.366-3.911), high mMRC score ( OR=1.484, 95% CI: 1.053-2.091), occupational exposure ( OR=1.513, 95% CI: 1.082-2.116), comorbid bronchiectasis ( OR=2.452, 95% CI: 1.102-5.457), low BMI ( OR=0.935, 95% CI: 0.891-0.981), and high CAT-energy score ( OR=1.301, 95% CI: 1.149-1.473) were risk factors for fatigue in COPD patients. The CAT-energy score was highly correlated with the FACIT-F score ( r=0.260, P<0.001), and a CAT-energy score ≥2 could preliminarily screen COPD patients with fatigue. Conclusions:COPD patients with comorbid fatigue have a heavy symptom burden, are more likely to have a history of occupational exposure and bronchiectasis, and the CAT-energy score is of great reference value for screening COPD patients with fatigue.
7.Analysis of clinical characteristics of patients with chronic obstructive pulmonary disease complicated by anorexia
Dan PENG ; Tao LI ; Ping ZHANG ; Cong LIU ; Ling LIN ; Yuqin ZENG ; Ping CHEN ; Qing SONG
Journal of Chinese Physician 2025;27(6):809-814
Objective:To analyze the clinical characteristics of patients with chronic obstructive pulmonary disease (COPD) complicated by anorexia.Methods:This cross-sectional study included patients registered in the RealDTC study from May 2023 to December 2023. Demographic data, COPD Assessment Test (CAT) score, modified Medical Research Council (mMRC) dyspnea questionnaire score, Clinical COPD Questionnaire (CCQ) score, forced expiratory volume in one second (FEV 1), forced expiratory volume in the first second predicted of percentage (FEV 1%pred), FEV 1/forced vital capacity (FVC), Global Initiative for Chronic Obstructive Lung Disease (GOLD) grade, GOLD group, number of acute exacerbations and hospitalizations in the past year, and score of the Functional Assessment of Anorexia Cachexia Therapy-Anorexia/Cachexia Subscale-12 (FAACT-A/CS-12) were collected. Patients with a FAACT-A/CS-12 score ≤30 were diagnosed as having anorexia. Multivariate logistic regression analysis was used to evaluate the influencing factors of anorexia in COPD patients. Results:A total of 617 COPD patients were included, of whom 109(17.7%) had anorexia. Compared with non-anorexia patients, COPD patients with anorexia had higher age, CAT, mMRC and CCQ scores, and more acute exacerbations and hospitalizations in the past year, while body mass index, FEV 1, FEV 1%pred and FEV 1/FVC were lower (all P<0.05). The proportions of patients with primary education or below, GOLD 3-4 grade and GOLD E group were higher in COPD patients with anorexia (all P<0.05). Logistic regression analysis showed that a CAT score of 10-<20 [odds ratio ( OR)=4.017, 95% confidence interval ( CI): 1.673-59.645], a CAT score of 20-<30 ( OR=9.686, 95% CI: 3.777-24.842), a CAT score of ≥30 ( OR=78.286, 95% CI: 7.654-800.689) and ≥1 hospitalization in the past year ( OR=2.050, 95% CI: 1.292-3.254) were independent risk factors for anorexia in COPD patients (all P<0.05). Conclusions:COPD patients with anorexia have poor lung function, high symptom burden and high risk of acute exacerbation. Clinicians should pay attention to the management of COPD patients with anorexia and take corresponding intervention measures.
8.Clinical characteristics analysis of frailty in elderly patients with chronic obstructive pulmonary disease
Jing LI ; Qing SONG ; Cong LIU ; Ling LIN ; Ping ZHANG ; Yuqing ZENG ; Xin LI ; Fang PEI ; Ping CHEN ; Tao LI
Journal of Chinese Physician 2025;27(6):815-820
Objective:To analyze the clinical characteristics of frailty in elderly patients with chronic obstructive pulmonary disease (COPD).Methods:COPD patients aged ≥65 years registered in the RealDTC study from June 2023 to March 2024 were included. Demographic data, history of exacerbations in the past year, exposure to risk factors (smoking, biomass fuel exposure, occupational exposure), modified Medical Research Council (mMRC) dyspnea score, COPD Assessment Test (CAT) score, forced expiratory volume in the first second predicted of percentage (FEV 1%pred), forced expiratory volume in one second (FEV 1) to forced vital capacity (FVC), and comorbidities (bronchial asthma, bronchiectasis, pulmonary tuberculosis, cardiovascular disease, diabetes mellitus) were collected. According to Fried′s frailty phenotype, patients meeting any 3 of the 5 criteria were defined as frail and divided into a frailty group and a non-frailty group. Multivariate regression analysis was used to screen the related factors of frailty in elderly COPD patients, and the receiver operating characteristic (ROC) curve was used to calculate the area under the curve (AUC) of related factors for frailty assessment. Results:A total of 496 elderly COPD patients were included, of which 144(29.0%) had comorbid frailty. The frailty group had lower mass body index (BMI), FEV 1%pred, and FEV 1/FVC, higher mMRC and CAT scores, more exacerbations and hospitalizations in the past year (all P<0.001), and higher proportions of patients with junior high school education or below, Global Initiative for Chronic Obstructive Lung Disease (GOLD) group E, and GOLD grades 3 and 4 (all P<0.05). Multivariate regression analysis showed that low education level ( OR=2.117, 95% CI: 1.119-4.003), low BMI ( OR=0.927, 95% CI: 0.867-0.991), GOLD grade 4 ( OR=4.251, 95% CI: 1.477-12.235), high CAT score ( OR=1.174, 95% CI: 1.127-1.224), and high mMRC score ( OR=4.578, 95% CI: 3.364-6.231) were independent risk factors for frailty in elderly COPD patients (all P<0.05). The ROC curve showed that CAT score (AUC=0.78) and mMRC score (AUC=0.81) had the highest AUC for assessing frailty in elderly COPD patients. Conclusions:Elderly COPD patients with frailty have lower BMI, worse lung function, and more severe symptom burden. The results provide clinical reference for the management of frail elderly COPD patients.
9.Development and application of novel portable heat illness/stroke first-aid kit
Yong-hui ZHANG ; Lin-cheng MI ; Cong-tao GUO ; Qing-ping ZHU ; Qing SONG ; Jing-chun SONG
Chinese Medical Equipment Journal 2025;46(9):108-113
Objective To develop a portable heat illness/stroke first-aid kit for on-site first aid of heat illness patients and verify its application effect.Methods The portable heat illness/stroke first-aid kit was composed of a main box,an adjustable telescopic rod,adjustable shoulder straps,universal rollers and a thermal insulation container.The main box made of aluminum alloy material had the inner surface lined with Oxford cloth,which was equipped with an infrared cochlear thermometer,a nebulizer,first aid medicines,heat stroke medicines,a sun umbrella,a cooling blanket,etc;the adjustable telescopic rod was made of aluminum-magnesium alloy;the adjustable shoulder straps was made of high-density nylon webbing;the universal rollers were rubberized and had wheel brakes;the thermal insulation container was located in the lower storage compartment inside the main box,which used polyurethane(PU)material for thermal insulation.The data on on-site first aid of the patients with moderate heat illness or stroke at some institution from 2019 to 2022 were analyzed retrospectively,with the patients treated with the traditional methods enrolled into a control group and the ones with the first-aid kit into an experimental group.The temperature changes at 0,10,20,30,40,50 and 60 min after the start of treatment were investigated to compare the cooling effects of the two groups.Results The heat illness/stroke first-aid kit lowered the patient temperature effectively during the on-site first aid of the patients with moderate heat illness or stroke,with higher cooling speed and effect than the traditional methods,especially at the early stage of treatment.Conclusion The heat illness/stroke first-aid kit with complete functions and easy operation decreases temperature of heat illness patients efficiently,and can be applicable to the scenarios such as field training and outdoors high-temperature operation.[Chinese Medical Equipment Journal,2025,46(9):108-113]
10.Identification of Mycobacterium abscessus subsp.abscessus and subsp.massiliense based on MALDI-TOF MS and analysis for their characteristics
Xueya QIN ; Yong LIN ; Cong ZHOU ; Hui ZHANG ; Maosuo XU
Chinese Journal of Clinical Laboratory Science 2025;43(2):81-87
Objective To perform the identification at the subspecies-level of Mycobacterium abscessus(M.abscessus)and analyze its characteristics based on matrix-assisted laser desorption ionization time-of-flight mass spectrometry(MALDI-TOF MS).Methods Bi-otyper software was used to construct the predicted peak spectrum of M.abscessus subsp.abscessus and M.abscessus subsp.massiliense.The predicted peak spectrum was constructed with expected maximum peak value number of 70 and peak frequency of 100%in the ex-perimental group and control group,respectively.A blind test was performed on 31 strains of M.abscessus that were not used to con-struct predictive peak spectra to evaluate the identification efficiency of predictive peak spectra.FlexAnalysis software was used to sum-marize and analyze the list of mass spectral peak value of M.abscessus,and screen the specific peaks in mass spectra of different sub-species of M.abscessus.The principal component analysis(PCA)algorithm was used to perform the cluster analysis for the data from mass spectrometry of M.abscessus,and explore the feasibility of PCA clustering in distinguishing the subspecies of M.abscessus.Results In the experimental group,96.8%(30/31)of the strains were correctly identified,and one strain of M.abscessus subsp.massiliense with rough colony form was mistakenly identified as M.abscessus subsp.abscessus.In control group,77.4%(24/31)of the strains were correctly identified,but 7 strains of M.abscessus subsp.massiliense were incorrectly identified or unable to be identified.The identification efficiency in the experimental group was significantly better than that in the control group with statistical difference(X2=5.167,P=0.026).M.abscessus subsp.abscessus exhibited three specific peaks(m/z 4 001.67,4 386.81 and 4 963.17),and M.abscessus subsp.massiliense also exhibited three specific peaks(m/z 4 950.48,4 381.78 and 5 214.90).In the PCA 3D scatter plot,the data points of M.abscessus subsp.abscessus and M.abscessus subsp.massiliense were relatively dispersed without obvious clus-tering.The PC A dendrograph could be divided into six branches in which only four branches were composed of a single subspecies.The minimum level value of distance between M.abscessus subsp.abscessus and M.abscessus subsp.massiliense was about 0.1.Conclusion The predicted peak spectrum based on MALDI-TOF MS with the expected maximum peak number of 70 could accurately identify M.abscessus at the subspecies level.The specific peak of mass spectrometry method in this study should be feasible to distinguish the subspecies of M.abscessus subsp.abscessus and the subspecies of M.abscessus subsp.Massiliense,but PCA cluster analysis cannot be used as a means to distinguish M.abscessus subsp.abscessus from M.abscessus subsp.massiliense.

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