1.Evaluation of the immunogenic properties of whole-cell proteins isolated from Mycobacterium marinum
Hong-yang DUAN ; Rui-huan WANG ; Ma-chao LI ; Hai-can LIU ; Kang-lin WAN
Chinese Journal of Zoonoses 2025;41(6):603-608
In this study,we aim to evaluate the immunogenicity of the whole-cell proteins isolated from Mycobacterium marinum(MM).The findings of this research may provide scientific basis for the development of new candidate tuberculosis vaccines.Both MM 95014 and Mycobacteriumtuberculosis(MTB)H37Rv cells were routinely cultured and collected.After inactivation,whole-cell proteins were extracted by low-temperature ultrasonic fragmentation and mixed with DDA/Poly:IC adjuvant.The mixture was administered to BALB/c mice subcutaneously with 50 mg/mouse twice with an interval of 10 days.Blood sample was collected before each immunization,as well as 10 days after the last immunization.Blood samples and spleen tissue extracts were measured for serum antibody potency and cytokine levels by an enzyme-linked immunosorbent assay.An in vitro growth inhibition assay(MGIA)was used to assess the ability of mouse bone marrow-derived macrophages,collected after immunization with MM whole-cell proteins,to inhibit MTB growth.A MTB whole mycobacterium proteome microarray was applied to analyze the interaction between the serum in MM immunization group and MTB proteins.Our results indicated that,compared with the adjuvant group,MM whole-cell proteins induced higher levels of Th1 cytokines(IL-2,IFN-γ,IL-12,TNF-α)in the mice.The IgG and IgM antibody titers induced by MM immunization group reached 1∶608 874 and 1∶304 437,respectively.The MGIA results showed that the MM immunization group was able to significantly inhibit MTB growth in vitro.The MTB proteome microarray results indicated that there were 226 and 324 cross-proteins with IgG and IgM antibodies,respectively.This study suggested that MM whole-cell proteins can induce high levels of cellular and humoral immune responses in mice and exhibit strong inhibition of MTB growth in vitro.The results may suggest potential application value of MM whole-cell proteins as a novel candidate vaccine for tuberculosis.
2.Analysis of consistency between resistance genes and resistance phenotypes in Acinetobacter baumannii
Lin GU ; Yan GAO ; Jian-hong ZHAO ; Ruo-xi ZHANG
Chinese Journal of Zoonoses 2025;41(6):617-622
his study was aimed at understanding the drug resistance of Acinetobacter baumannii,exploring the consistency between resistance genes and resistance phenotypes,and providing a basis for the rational use of antibiotics in clinical practice.A total of 88 strains of Acinetobacter baumannii were isolated from hospitals at tertiary level or above within the jurisdiction from 2021 to 2023,and subjected to drug resistance testing and whole genome sequencing.The original data were analyzed for the entire genome process with a Microobench pathogenic microorganism analysis workstation(without reference splicing),and resistance genes were predicted and annotated.The strains were subjected to multi-point sequence analysisand minimum spanning tree construction.Among 88 strains of Acinetobacter baumannii,carbapenem resistant strains(CRAB)accounted for 72.73%,and 98.44%of CRAB showed multidrug resistance.In the past three years,the resistance to multiple drugs has increased.The cgMLST analysis showed that the ST2 type accounted for 89.77%,and a new ST type was discovered.After cgMLST analysis,the minimum spanning tree was generated,and the genetic relationship of the same ST type was closer.The same ST2 type was further divided into four clusters.Binary logistic regression analysis conducted on resistance genes and resistance phenotypes revealed that resistance genes APH(3″)-Ib,armA,ADC-73,sul1,and sul2 positively correlated with resistance phenotypes.The ST2 type was the main Acinetobacter baumannii type,and showed high rates of multidrug resistance and carriage of multiple resistance genes.The drug resistance situation is severe.The consistency between common resistance genes and resistance phenotypes is good.Clinical management of Acinetobacter baumannii infection must be strengthened to prevent outbreaks and transmission.
3.Distribution and source tracing analysis of drug-resistant bacteria in the environment at pig farms in Shandong Province
Shu-meng YOU ; Yong WANG ; Da-yang ZOU ; Hong-bin WANG ; Jun-zhu BAI ; Dan-jie ZHANG ; Liang WEN ; Yuan-yong XU ; Wen-yi ZHANG
Chinese Journal of Zoonoses 2025;41(6):623-628
This study investigated the drug resistance and genetic relationships among strains co-existing in animals,the environ-ment,and the living quarters of employees at large-scale pig farms in certain regions of Shandong Province,to provide a scientific ba-sis for elucidating the transmission mechanisms of drug-resistant bacteria through bacterial traceability analysis.Samples were col-lected from two pig farms,and bacteria were isolated and purified.The species of the isolated strains were identified via 16S rRNA gene sequencing.Antimicrobial susceptibility testing was conducted with a VITEK-2 Compact system and the disk diffusion method for strains present in pigs,the environment,and living areas.Furthermore,whole-genome sequencing was performed on the Illumina Miniseq platform to annotate drug resistance genes,and multilocus sequence typing(MLST)and core genome single nucleotide poly-morphism(cgSNP)analyses were used to trace the resistant strains.Three species—Staphylococcus aureus,Pseudomonas aeruginosa,and Bacillus cereus—were isolated and cultured from animals,the environment,and employee living areas,and their distributions were analyzed.These strains exhibited diverse drug resistance spectra and genetic diversity.Additionally,the strains displayed highly consistent resistance profiles,resistance genes,ST types,and SNP loci in pig urine,soil both inside and outside the facility,human drinking water,and the cafeteria and dormitories.Our findings indicated a potential risk of transmission of opportunistic pathogens be-tween the pig farming area and the living quarters.Particular attention should be paid to the environmental transmission of methicillin-resistant Staphylococcus aureus.
4.Isolation,identification,and biological characterization of a Streptococcus equinus strain from sheep
Hai-li WANG ; Xiu-sheng YIN ; Qi JIA ; Feng-yuan ZHANG ; Ling MO ; Lin LI ; Jing DONG ; Jin-liang WANG
Chinese Journal of Zoonoses 2025;41(6):641-647
Streptococcus equinus is a zoonotic disease that can cause illness in various animals under specific environmental condi-tions.No reports have described isolation of this bacterium from the liver in affected sheep.This study successfully isolated and identi-fied a strain of Streptococcus equinus through bacterial isolation and culture,Gram staining,drug sensitivity testing,mouse sensitivity testing,bacterial biochemical testing,and whole genome sequencing.The strain was found to have pathogenicity toward Kunming white mice,and to be sensitive to four antibiotics(penicillin,ampicillin,ceftiofur sodium,and ceftriaxone sodium)but resistant to four antibiotics(streptomycin,amoxicillin,tetracycline,and gentamicin).On the basis of drug sensitivity testing,targeted treatment of the affected sheep flock with ceftiofur sodium effectively controlled the disease within 2 days,and no new cases occurred.This study provides a reference for biological characterization of ovine Streptococcus equinus;public health;and the investigation of disease pre-vention,control,and epidemiology.
5.Genetic diversity,virulence factors,and antibiotic resistance of Listeria monocytogenes from livestock and poultry meat and clinical samples in Weifang during 2020-2023
Yi-meng WANG ; Ming-ming YU ; De-hui LIU ; Xiao-yan HAO ; Li-dan JIANG ; Zhi-peng REN
Chinese Journal of Zoonoses 2025;41(6):629-635
This study was aimed at understanding the antimicrobial resistance patterns,virulence characteristics,and phyloge-netic relationships of foodborne Listeria monocytogenes in Weifang.A total of 67 strains of Listeria monocytogenes were isolated from livestock,poultry meat,and clinical samples in Weifang between 2020 and 2023.The susceptibility of these isolates was determined through broth microdilution.Whole-genome sequencing and genetic characterization of these isolates were conducted.The 67 strains were divided into 12 STs,among which ST121,ST8,ST9,and ST87 predominated(76.12%).Eight groups of closely related strains were identified through cgMLST typing.Three Listeria pathogenicity islands and two genomic islands were identified in all strains:100%of the strains carried LIPI-1,5.97%carried LIPI-3,14.93%carried LIPI-4,2.99%carried LGI-2,and 4.48%of the strains carried LGI-3.No antibiotic resistance genes were found in any strains.All isolates were susceptible to ampicillin,penicillin,merope-nem,trimethoprim-sulfamethoxazole,and vancomycin.Five isolates were resistant to tetracycline,and three strains of ST87,one strain of ST8,one strain of ST224,and two strains of ST87 were simultaneously resistant to erythromycin.The tet(M)tetracycline re-sistance genes and msr(D)and mef(A)erythromycin resistance genes from three strains of ST87 and one strain of ST8 were carried by a phage similar to phi1605 in Erysipelothrix,with>95%identity.The tet(M)gene from the ST224 isolates was carried by a transposon similar to Tn5801_B15 in Enterococcus faecalis,with>95%identity.Drug-resistant strains of Listeria monocytogenes were found in livestock and poultry meat on sale in Weifang,particularly strains of type ST87 and ST224 simultaneously carrying highly pathogenic virulence islands,thus posing a threat to food safety and public health.These findings therefore warrant attention from relevant depart-ments and strengthened monitoring efforts.
6.Antimicrobial susceptibility and phylogenetic analysis of 31 Nocardia isolates
Xin-yan DONG ; Li-heng ZHENG ; Wei-li GAO ; Hong ZHANG ; Fei LU ; Yu-mei GUO
Chinese Journal of Zoonoses 2025;41(6):636-640
This study investigated the disease characteristics and clinical traits of Nocardia infection,and analyzed the antibiotic resistance phenotypes,antibiotic resistance genes,and evolutionary characteristics of the strains,to provide a basis for Nocardia diag-nosis and treatment.A total of 31 Nocardia strains from a hospital in Hebei Province were collected from 2020 to 2023.The strains were identified through mass spectrometry and whole genome sequencing.Antibiotic susceptibility testing was conducted with the broth macrodilution method,and whole genome sequencing data were used to predict antibiotic resistance genes and comprehensively ana-lyze antibiotic resistance phenotypes.The 31 strains of Nocardia comprised 21 strains of Nocardia farcinica,3 strains of Nocardia ter-penica,three strains of Nocardia brasiliensis,two strains of Nocardia cyriacigeorgica,and two strains of Nocardia nova.The ceftriaxone susceptibility of 21 Nocardia farcinica strains was 85.7%,and all 31 strains were susceptible to imipenem,except for three strains of Nocardia brasiliensis.Rifampicin,aminoglycoside,and β-lactam resistance genes were found in Nocardia farcinica.Pathogenic tests should be carried out in a timely manner for suspected Nocardia infections.In clinical treatment of Nocardia infection,infected strains should be confirmed,and antibiotics should be used rationally according to the antibiotic susceptibility test results.
7.Comparison of clinical manifestations,laboratory characteristics,and treatment outcomes of 258 patients with acute and chronic brucellosis
Xu ZHAO ; Ke-mei NIU ; Xia GAO ; Chun-xu SONG ; Yu FAN ; Qing-qing XU ; Zhong-rong LU ; Kun LI ; Feng GAO ; Mei-chun HAO ; Bing-zhi LIU ; Hai JIANG
Chinese Journal of Zoonoses 2025;41(6):660-667
To compare and analyze the clinical manifestations,laboratory characteristics,imaging findings,and treatment outcomes of patients with acute and chronic brucellosis,a retrospective analysis was conducted on 258 patients with brucellosis(202 in the acute group and 56 in the chronic group)hospitalized in Xinkang Hospital in Dalad Banner,Ordos City,Inner Mongolia Autonomous Region,from November 2023 to November 2024.General data,epidemiological characteristics,clinical presentations,laboratory test results,imaging findings,treatment outcomes,and prognosis were collected.The incidences of fever(51.5%vs 7.1%),fatigue(30.2%vs 12.5%),joint pain(42.9%vs 16.1%),and muscle pain(9.9%vs.1.8%)were significantly higher in the acute phase group(all P<0.05).The incidence of osteoarthritis complications was higher in the chronic brucellosis group(51.8%vs 8.9%,χ2=75.697,P<0.01).Univariate ANOVA analysisshowed that the Serum Agglutination Tests(SAT),alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),creatinine(CRE),C-reactive protein(CRP),erythrocyte sedimentation rate(ESR),and bone destructionexhibited statistically significant differences between the acute and chronic phases of brucellosis(all P<0.05).Multivariate logistic regression analysis indicated that abnormal ALT(OR=14.18,95%CI:1.11-181.72;P=0.041)and bone destruction(OR=0.16,95%CI:0.04-0.63;P=0.009)were associated with chronic brucellosis.After treatment,all patients experienced have symptom relief in varying degrees,with 157 patients(60.9%)cured and 101 patients(39.1%)symptomatic improved(P<0.01).In conclusion,the incidences of fever,fatigue,and joint pain in patients during the acute phase is significantly higher than that those in patients during the chronic phase,while the incidence of osteoarthritis complications is higher in chronic phase patients.The incidences of abnormal SAT,ALT,AST,TBIL,CRE,CRP,and ESR,and bone destruction varies at different stages of brucellosis.Of those,abnormal ALT and bone destruction show a stronger association with,which can assist the clinical staging of brucellosis.
8.Spatial-temporal distribution characteristics of an animal plague epidemic in marmot foci in the Qilian-Altun Mountains of Gansu Province,2014-2023
Ding-sheng WANG ; Xiao-jie ZHOU ; Wen-jing AN ; Jin-xiao XI ; Da-qin XU ; Li-min GUO
Chinese Journal of Zoonoses 2025;41(6):668-674
This study was analyzed the spatial-temporal distribution and aggregation characteristics of Yersinia pestispositive host animals and vector pathogens in marmot natural foci in the Qilian-Altun mountains,Gansu Province,to provide a scientific basis for precise plague prevention and control.Y.pestissurveillance data for marmot natural foci in Qilian-Altun Mountains of Gansu Province from 2014 to 2023 were obtained from the Disease Control and Prevention Center of Gansu Province.Origin 2024 software was used for data visualization and presentation.Global and local spatial autocorrelation analyses and trend analyses were conducted in ArcGIS 10.8 software,with townships as the spatial scale.Cumulatively,440 strains of Y.pestis were isolated from the natural marmot foci in the Qilian-Altun mountainsof Gansu Province from 2014 to 2023.Most strains was isolated from marmots(345 strains,78.41%),and the remainder were isolated from vectors.Temporal distribution analysis indicated that the highest number of detected bacteria was reported in July and August(both 121 strains,27.50%).Regional distribution analysis revealed that Aksai County reported the highest number of detected bacteria(255 strains,57.95%).Global spatial autocorrelation analysis showed a spatially clustered distribution of the number of bacteria detected annually in the townships containing natural foci,except in2014,2016,and 2021-2023.The strongest spatial clustering was observed in 2020(Moran's I=0.521 2,Z=14.397 0,P<0.001).Local spatial autocorrelation analysis indicated a"high-high"aggregation area in the natural foci every year from 2014 to 2023,primarily in Hongliuwan Town of Aksai County and Dangchengwan Town of Subei County.The distribution of the"low-low"aggregation area was essentially consistent with the low activity area of the Yersinia pestisepidemic.The trend in annual total bacterial count gradually increased from east to west,and peaked in the western part of the epidemic focus.Clear spatial aggregation characteristics of the number of Y.pestis were detected in the marmot natural foci in the Qilian-Altun mountains at the townshiplevel as a whole in Gansu Province from 2014 to 2023.The aggregation area was mainly in the western section of Qilian Mountain to the Altun mountain section of the epidemic source area.Monitoring and prevention and control efforts should be focused in this key area,with prevention and control measures tailored to the local conditions,and classified guidance to decrease the risk of plague occurrence and spread.
9.New Research progress in virulence factors of Streptococcus suis
Yu-jie WEI ; Da-han YANG ; Xue-wu YU
Chinese Journal of Zoonoses 2025;41(6):648-652
Streptococcus suis is an important zoonotic pathogen.Two outbreaks of large-scale human infections with S.suis have occurred in China,thereby posing a serious public health risk and changing the view that this pathogen causes only sporadic cases in humans.Deeper understanding of the pathogenesis of Streptococcus suis is urgently needed.During the infection process,S.suis sur-vival and virulence in the host is facilitated by circumvention of the immune defense through various virulence factors.The bacterium's pathogenicity is closely associated with the virulence factors it carries.Herein,we review recent progress in the study of virulence fac-tors of S.suis related to overcoming the host intrinsic immune defense,to provide a theoretical basis for the prevention of porcine strep-tococcal diseases and the development of vaccines.
10.Effects of the Ccdc115 gene on the phagosome acidification and viability of RAW264.7 cells infected with Salmonella Typhimurium
Rong-xian XIE ; Long-yun CHENG ; Xi-lu YUAN ; Li LI ; Bing-qing LI ; Hai-hong JIA
Chinese Journal of Zoonoses 2025;41(6):559-566
This work was aimed at analyzing the protein characteristics of Coiled-Coil Domain-Containing Protein 115(CCDC115)and using Ccdc115-deficient mouse monocyte-macrophage leukemia cells(RAW264.7)to explore the influence of CCDC115 on the intracellular survival of Salmonella Typhimurium.Bioinformatics analysis was conducted to examine the fundamental attributes of CCDC115,which was determined to be an unstable protein consisting of two α-helices and an intervening disordered re-gion,devoid of any transmembrane structural domains.A RAW264.7-Ccdc115-KO cell line was successfully established with CRISPR/Cas9 gene-editing technology.To elucidate the effects of CCDC115 on the intracellular survival of Salmonella Typhimurium,we infected RAW264.7 cells with Salmonella Typhimurium.The expression of CCDC115 was found to be upregulated at both the mRNA and protein levels post-infection,according to RT-qPCR and western blot analysis.Via counting of colony-forming units(CFU),the proliferation rate of Salmonella Typhimurium within RAW264.7-Ccdc115-KO cells was found to be 1.5-fold higher than that in RAW264.7 cells.Acidification imaging studies indicated that,whereas Salmonella Typhimurium phagosomes underwent acidifi-cation in RAW264.7 cells,this process was absent in RAW264.7-Ccdc115-KO cells.In conclusion,the study successfully estab-lished a RAW264.7-Ccdc115-KO cell line and demonstrated that the expression of CCDC115 is elevated during Salmonella Ty-phimurium infection,thus potentially inhibiting the intracellular survival of Salmonella Typhimurium by facilitating phagosome acidifi-cation.This study lay a theoretical foundation for functional studies of CCDC115 and the investigation of mechanisms regulating the survival of intracellular Salmonella Typhimurium.

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