Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from...Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from January 2022 to January 2023.Methods:GBS strains were isolated through selective culture methods and confirmed by PCR.Serotyping,virulence gene detection,and antibiotic susceptibility testing were performed using PCR,gel electrophoresis techniques and Kirby-Bauer test.Results:Totally,61 GBS isolated from 300 participants have been identified including seven GBS serotypes(Ⅰa,Ⅰb,Ⅱ,Ⅲ,Ⅳ,Ⅴ,andⅥ).SerotypesⅦ,Ⅷ,andⅨwere not detected in the study population.Antibiotic resistance patterns varied:13.1%of isolates were fully susceptible,while the majority showed multi-drug resistance,with 34.4%resistant to three antibiotics.SerotypeⅠa demonstrated high susceptibility(35.7%),while serotypeⅢshowed extensive resistance,with 87.5%being resistant to at least three antibiotics.All strains are susceptible to vancomycin andβ-lactams susceptibility also remained high,but resistance to clindamycin,erythromycin,and tetracycline was high(>65%).The virulence genes scpB,cylB,fbsB,and cfb were highly prevalent(90%-100%),indicating their potential for vaccine and diagnostic development.Conclusions:Our findings provide valuable insights into GBS serotypes,resistance,and virulence factors,contributing to community monitoring,preventive measures,diagnostics,and vaccine development.However,the limited sample size necessitates further research.展开更多
Objective Pseudomonas aeruginosa(P.aeruginosa)is a prevalent pathogenic bacterium involved in meningitis;however,the virulence factors contributing to this disease remain poorly understood.Methods The virulence of the...Objective Pseudomonas aeruginosa(P.aeruginosa)is a prevalent pathogenic bacterium involved in meningitis;however,the virulence factors contributing to this disease remain poorly understood.Methods The virulence of the P.aeruginosa A584,isolated from meningitis samples,was evaluated by constructing in vitro blood-brain barrier and in vivo systemic infection models.qPCR,whole-genome sequencing,and drug efflux assays of A584 were performed to analyze the virulence factors.Results Genomic sequencing showed that A584 formed a phylogenetic cluster with the reference strains NY7610,DDRC3,Pa58,and Pa124.Its genome includes abundant virulence factors,such as hemolysin,the Type IV secretion system,and pyoverdine.A584 is a multidrug-resistant strain,and its wide-spectrum resistance is associated with enhanced drug efflux.Moreover,this strain caused significantly more severe damage to the blood-brain barrier than the standard strain,PAO1.qPCR assays further revealed the downregulation of the blood-brain barrier-associated proteins Claudin-5 and Occludin by A584.During systemic infection,A584 exhibited a higher capacity of brain colonization than PAO1(37.1×10^(6) CFU/g brain versus 2.5×10^(6) CFU/g brain),leading to higher levels of the proinflammatory factors IL-1βand TNF-α.Conclusion This study sheds light on the virulence factors of P.aeruginosa involved in meningitis.展开更多
Bacterial infections of avian embryos can lead to an increase in embryo mortality,and the proliferation of antimicrobial-resistant bacteria aggravates the situation.A low hatching rate also poses a challenge to the po...Bacterial infections of avian embryos can lead to an increase in embryo mortality,and the proliferation of antimicrobial-resistant bacteria aggravates the situation.A low hatching rate also poses a challenge to the population of artificially bred Crested Ibises(Nipponia nippon).This study aims to determine the potential association between bacterial infection and the death of Crested Ibis embryos,and whether there is convergence between antimicrobial resistance and virulence in strain.In this study,13 Escherichia coli and 12 Proteus mirabilis isolates were recovered from dead Crested Ibis embryos.The pathogenicity examination confirmed the pathogenicity of all isolates,and multiple virulence genes detected by PCR-sequencing demonstrated the presence of irp2 and iuc D(100%),fim C and iss(92.31%)in E.coli,and uca A(58.33%)in P.mirabilis.Antimicrobial susceptibility test demonstrated that isolates were mainly resistant to amoxicillin(E.coli:76.92%,P.mirabilis:91.67%),cefazolin(E.coli:76.92%,P.mirabilis:91.67%),oxytetracycline(E.coli:92.31%,P.mirabilis:75.00%)and sulfamethoxazole-trimethoprim(E.coli:53.85%,P.mirabilis:33.33%),and more than 30%of isolates showed multidrug-resistance(MDR).Further analyses detected extended-spectrumβ-lactamase(ESBL)genes,of which blaTEM-1(E.coli:100%,P.mirabilis:100%)had the highest frequency,followed by the blaCTX-M-55(E.coli:92.31%,P.mirabilis:50%),blaCTX-M-14(E.coli:76.92%,P.mirabilis:33.33%),blaCTX-M-65(E.coli:15.38%,P.mirabilis:16.67%),and all isolates were negative for blaSHV and blaOXA.Pearson's correlation analysis showed a positive correlation between the presence ofβ-lactam resistance and ESBL genes,while mainly negative correlations were observed between the presence of ESBL genes and virulence genes.Furthermore,the conjugation experiment and PFGE revealed that the isolates were primarily polyclonal,and there was horizontal transfer of resistance or virulence genes by plasmids.Based on the results,E.coli and P.mirabilis were responsible for embryonic mortality of the ibises in this study.The co-presence and co-transfer of ESBL genes and virulence genes can pose a potential threat to the health of the Crested Ibis,and measures such as prudent use of antimicrobials,and constant surveillance of resistance and pathogenicity,must be implemented at the Crested Ibis breeding base.展开更多
Aeromonas veronii is considered an emerging food-borne pathogen associated with a significant threat to public health,distributed in various aquatic environments and products.Hanks-type serine/threonine kinases(STKs)p...Aeromonas veronii is considered an emerging food-borne pathogen associated with a significant threat to public health,distributed in various aquatic environments and products.Hanks-type serine/threonine kinases(STKs)play a critical role in the pathogenesis of pathogens.However,the function of A.veronii STKs is currently unclear.By constructing a markerless prk A in-frame deletion strain,Δprk A,we found that i)the colonies of theΔprk A strain were larger after 1 h of high temperature at 50℃compared with the wild-type strain TH0426 and the complementary strain C-prk A,and the number of viable bacteria of theΔprk A strain increased significantly;ii)theΔprk A strain significantly enhanced the adhesion ability to epithelioma papulosum cyprini(EPC)cells;iii)theΔprk A strain was significantly more virulent than the TH0426 strain,at both the cellular and animal levels;and iv)RNA-seq results showed a total of 984 differentially expressed genes(DEGs)between theΔprk A strain and the TH0426 strain,which were enriched in 70 Kyoto Encyclopedia of Genes and Genomes(KEGG)metabolic pathways,mainly involved in bacterial ribosomes,flagellar assembly,type Ⅱ secretion system(T2SS),and lipopolysaccharide metabolic pathways.Taken together,the findings of this study indicate that the Hanks-type STK Prk A negatively regulates several biological processes,such as the temperature tolerance and virulence of A.veronii.The results of this study provide an important reference for further elucidation of the pathogenesis of A.veronii.展开更多
Helicobacter pylori infection represents a widespread chronic condition with varying prevalence influenced by race, ethnicity, and geography. The severity of H. pylori-associated diseases is determined by an array of ...Helicobacter pylori infection represents a widespread chronic condition with varying prevalence influenced by race, ethnicity, and geography. The severity of H. pylori-associated diseases is determined by an array of virulence factors. Although extensive studies have been conducted globally, data on the distribution of Helicobacter pylori virulence genes in Libya remain limited, constraining insights into the pathogenicity of local strains and hindering the development of targeted interventions. This study aimed to evaluate the prevalence of H. pylori infection, characterize essential virulence genes [vacA variants (s1/s2, m1/m2), cagA, and iceA1], and examine their association with gastroduodenal diseases among Libyan patients. Gastric biopsies from 144 participants were analyzed using polymerase chain reaction (PCR) assays, and risk factor data were collected via questionnaires. H. pylori was detected in 63.2% of samples by PCR. The vacA gene was present in 84.6% of cases, cagA in 58.2%, and iceA1 in 29.7%. Among vacA variants, s1 allele was most common (53.2%), followed by m1 (42.9%), m2 (37.7%), and s2 (13%) alleles. Significant associations were identified between specific virulence genes and the development of gastroduodenal diseases, highlighting their role in pathogenicity. This investigation is one of Libya’s first comprehensive assessments of H. pylori virulence factors, addressing a critical epidemiological gap. The high prevalence of virulence genes suggests their potential as disease biomarkers. These findings contribute to a deeper understanding of H. pylori pathogenicity within the Libyan population and establish a basis for future clinical interventions and public health strategies to manage and prevent H. pylori-associated diseases in Libya and comparable regions.展开更多
The velvet protein family serves as a crucial factor in coordinating development and secondary metabolism in numerous pathogenic fungi.However,no previous research has examined the function of the velvet protein famil...The velvet protein family serves as a crucial factor in coordinating development and secondary metabolism in numerous pathogenic fungi.However,no previous research has examined the function of the velvet protein family in Fusarium oxysporum f.sp.niveum(FON),a pathogen causing a highly destructive disease in watermelon.In this study,∆fovel1 and∆folae1 deletion mutants and∆fovel1-C and∆folae1-C corresponding complementation mutants of FON were validated.Additionally,the phenotypic,biochemical,and virulence effects of the deletion mutants were investigated.Compared to the wild-type strains,the∆fovel1 and∆folae1 mutants exhibited altered mycelial phenotype,reduced conidiation,and decreased production of bikaverin and fusaric acid.Furthermore,their virulence on watermelon plant roots significantly decreased.All these alterations in mutants were restored in corresponding complementation strains.Notably,yeast two-hybrid results demonstrated an interaction between FoVel1 and FoLae1.This study reveals that FoVEL1 and FoLAE1 play essential roles in secondary metabolism,conidiation,and virulence in FON.These findings enhance our understanding of the genetic and functional roles of VEL1 and LAE1 in pathogenic fungi.展开更多
[Objective] This study aimed to explore the presence of three causative genes Colv,Stxs and HlyE of the pathogenic E.coli from chickens,pigs and food.[Method] By using 44 E.coli strains from chickens,24 from pigs and ...[Objective] This study aimed to explore the presence of three causative genes Colv,Stxs and HlyE of the pathogenic E.coli from chickens,pigs and food.[Method] By using 44 E.coli strains from chickens,24 from pigs and 26 from food as the experimental materials,virulence genes Colv,Stxs（stx2,stx2e） and HlyE were detected with polymerase chain reaction（PCR） method.[Result] Among all the E.coli strains,the detection rate of Colv was 25% from chickens,4.2% from pigs,and 0 from food;the detection rate of Stx2（Stx2e） from all E.coli strains was 0;the detection rate of HlyE was 2.27% from chickens,0 from pigs,and 11.5% from food.[Conclusion] Virulence gene Colv shows relatively high carrying rate in E.coli from chickens and pigs;HlyE also shows a certain degree of presence in E.coli from chickens and food.展开更多
A total of 638 isolates of rice blast （Magnaporthe oryzae） were isolated in 2002-2009 from different rice varieties in different regions of Sichuan, China and inoculated onto seven rice varieties （Lijiangxintuanhei...A total of 638 isolates of rice blast （Magnaporthe oryzae） were isolated in 2002-2009 from different rice varieties in different regions of Sichuan, China and inoculated onto seven rice varieties （Lijiangxintuanheigu, IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1） to differentiate the virulence types of the fungus and trace the changes. The virulence to the seven varieties was respectively scored at 1, 2, 4, 8, 16, 32 and 64. The total scores of individual M. grisea isolates which were the sum of scores infecting differential varieties could, in turn, be used for the nomenclature of the virulence types due to their accordance to the special virulence patterns. The 638 tested isolates were then differentiated into 56 different virulence types. Type 15 virulent to Lijiangxintuanheigu, IR24 and Minghui 63, and Type 127 virulent to all of the seven varieties were the most dominant virulence types respectively with the occurrence frequencies of 15.99% and 15.83%. Type 19 and other seven virulence types were not monitored during 2002-2009. Type 15 was the predominant virulence type in 2002, 2003, 2004 and 2007, whereas Type 127 had been the most dominant virulence type after 2005 except for the year 2007 when the province underwent severe drought. Five hundred and seven out of the 638 tested isolates were virulent to Minghui 63, and 89.58% of the 384 isolates virulent to either Duohui 1, Chenghui 448 or Neihui 99-14 were virulent to Minghui 63, which indicated the impact of the extensive plantation of hybrid rice Minghui 63 as the restorer line on the virulence evolution of M. oryzae in Sichuan. The virulence pattern of the dominant virulence types suggested that the acquiring of virulence to all the major resistant restorer lines was the main routes of the evolution in virulence of M. oryzae to hybrid rice in Sichuan. The virulence frequencies of the 638 tested isolates to IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1 were respectively 74.6%, 79.5%, 73.8%, 37.0%, 39.0% and 40.4%. The analysis for the sources of the different virulence type isolates indicated the pathogen on the newly released resistant varieties were stronger than conventional rice varieties which had become susceptible in the field since 1980s.展开更多
Fungal pathogen of asparagus stem blight was isolated. No significant genetic difference was detected among the three strains with 492 bp long ITS1-5.8S-ITS2 sequence. It was then identified through colony growth, con...Fungal pathogen of asparagus stem blight was isolated. No significant genetic difference was detected among the three strains with 492 bp long ITS1-5.8S-ITS2 sequence. It was then identified through colony growth, conidia morphology, and molecular characterization. The physiological response to oxidation and osmosis stress, and virulence to Asparagus officinalis L. were analyzed. The results showed that the pathogen causing asparagus stem blight for A. officinalis L. in Jiangxi Province is Phomopsis asparagri (Sacc.) Bubák. Under pure culture conditions, the conidia were oval-shaped (α-type), with colorless single spore and single nucleus, containing 0-2 oil balls. Its vegetative growth rate was higher when cultured on 0.2 × potato dextrose agar (0.2 × PDA) medium than that on oatmeal agar (OA) medium. However, the pycnidia appeared earlier on OA medium than on 0.2 earlier PDA medium. The vegetative growth rate was depressed under oxidation (H2O2) or osmosis (NaCl) stress conditions, and totally inhibited under 7 mmol/L H2O2 or 2.4 mol/L NaCl. All the strains caused typical pathogenic symptoms to Asparagus officinalis L. at 7 days-post-inoculation (dpi) with conidia.展开更多
Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop seriou...Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop serious gastroduodenal pathology.The pathogenesis of H.pylori infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence factors.H.pylori has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial cells.These virulence factors enable successful colonization of the gastric mucosa and sustain persistent H.pylori infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric cancer.Numerous studies have focused on the prevalence and role of putative H.pylori virulence genes in disease pathogenesis.While several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study populations.This review presents key findings on the most important H.pylori virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.展开更多
Helicobacter pylori(H. pylori) is a model organism for understanding host-pathogen interactions and infection-mediated carcinogenesis. Gastric cancer and H. pylori colonization indicates the strong correlation. The pr...Helicobacter pylori(H. pylori) is a model organism for understanding host-pathogen interactions and infection-mediated carcinogenesis. Gastric cancer and H. pylori colonization indicates the strong correlation. The progression and exacerbation of H. pylori infection are influenced by some factors of pathogen and host. Several virulence factors involved in the proper adherence and attenuation of immune defense to contribute the risk of emerging gastric cancer, therefore analysis of them is very important. H. pylori also modulates inflammatory and autophagy process to intensify its pathogenicity. From the host regard, different genetic factors particularly affect the development of gastric cancer. Indeed, epigenetic modifications, Micro RNA and long non-coding RNA received more attention. Generally, various factors related to pathogen and host that modulate gastric cancer development in response to H. pylori need more attention due to develop an efficacious therapeutic intervention. Therefore, this paper will present a brief overview of host-pathogen interaction especially emphases on bacterial virulence factors, interruption of host cellular signaling, the role of epigenetic modifications and non-coding RNAs.展开更多
AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reac...AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n =16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. RESULTS: A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of theasa1 gene and thegelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain ofEnterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent amongEnterococcus strains isolated from children with IBD than in control strains. CONCLUSION: Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.展开更多
African swine fever virus(ASFV)is the etiological agent of African swine fever(ASF),an often lethal disease in domestic and wild pigs.ASF represents a major threat to the swine industry worldwide.Currently,no commerci...African swine fever virus(ASFV)is the etiological agent of African swine fever(ASF),an often lethal disease in domestic and wild pigs.ASF represents a major threat to the swine industry worldwide.Currently,no commercial vaccine is available because of the complexity of ASFV or biosecurity concerns.Live attenuated viruses that are naturally isolated or genetically manipulated have demonstrated reliable protection against homologous ASFV strain challenge.In the present study,a mutant ASFV strain with the deletion of ASFV MGF-110-9L(ASFV-D9L)was generated from a highly virulent ASFV CN/GS/2018 parental strain,a genotypeⅡASFV.Relative to the parental ASFV isolate,deletion of the MGF-110-9L gene significantly decreased the ability of ASFV-D9L to replicate in vitro in primary swine macrophage cell cultures.The majority of animals inoculated intramuscularly with a low dose of ASFV-D9L(10 HAD50)remained clinically normal during the 21-day observational period.Three of five ASFV-D9L-infected animals displayed low viremia titers and low virus shedding and developed a strong virus-specific antibody response,indicating partial attenuation of the ASFV-D9L strain in pigs.The findings imply the potential usefulness of the ASFV-D9L strain for further development of ASF control measures.展开更多
AIM: To better understand the pathogenic role of Helicobacter pylori (H. pylori) in pre-eclampsia (PE), and whether it is associated or not with fetal growth retardation (FGR). METHODS: Maternal blood samples were col...AIM: To better understand the pathogenic role of Helicobacter pylori (H. pylori) in pre-eclampsia (PE), and whether it is associated or not with fetal growth retardation (FGR). METHODS: Maternal blood samples were collected from 62 consecutive pregnant women with a diagnosis of PE and/or FGR, and from 49 women with uneventful pregnancies (controls). Serum samples were evaluated by immunoblot assay for presence of specific antibodies against H. pylori antigens [virulence: cytotoxin-associated antigen A (CagA); ureases; heat shock protein B; flagellin A; persistence: vacuolating cytotoxin A (VacA)]. Maternal complete blood count and liver enzymes levels were assessed at delivery by an automated analyzer. RESULTS: A significantly higher percentage of H. pyloriseropositive women were found among PE cases (85.7%) compared to controls (42.9%, P < 0.001). There were no differences between pregnancies complicated by FGR without maternal hypertension (46.2%) and controls. Importantly, persistent and virulent infections (VacA/ CagA seropositive patients, intermediate leukocyte blood count and aspartate aminotransferase levels) were exclusively associated with pre-eclampsia complicated by FGR, while virulent but acute infections (CagA positive/ VacA negative patients, highest leukocyte blood count and aspartate aminotransferase levels) specifically correlated with PE without FGR. CONCLUSION: Our data strongly indicate that persistent and virulent H. pylori infections cause or contribute to PE complicated by FGR, but not to PE without feto-placental compromise.展开更多
AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastr...AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole. Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot. The mutation of the genes including ureA, ureB,hpaA, vacA and cagA, related with virulence, was detected by means of PCR and PCR-SSCP. RESULTS: In the coccoid H. pylori,the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells all decreased. In strain F44, the rate and index of adherence reduced from 70.0% +/- 5.3% to 33% +/- 5.1% and from 2.6 +/- 0.4 to 0.96 +/- 0.3 (P 【 0.01), respectively. The invasion of coccoid H. pylori into Hep-2 cell could be seen under electronmicroscope. SDS-PAGE showed that the content of the protein with the molecular weight over Mr 74000 decreased, and the hybriditional signal in band M(r) 125000 weakened, while the band M(r)110000 and M(r)63000 strengthened in coccoid H.pylori as shown in Western blot. The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA. CONCLUSION: The virulence and the proteins with molecular weight over M(r)74000 in coccoid H.pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA, vacA and cagA genes, suggesting that coccoid H.pylori may have potential pathogenicity.展开更多
Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important disease in China. To characterize the virulence and diversity of the pathogen, 1 082 isolates were obtained from 8 major wheat-growing ...Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important disease in China. To characterize the virulence and diversity of the pathogen, 1 082 isolates were obtained from 8 major wheat-growing regions during the spring growing season in 2011. The virulence test was performed by inoculation on detached leaves of 22 differential lines with known Pm genes. Frequencies of virulence on these genotypes ranged from 0 to 97.4%. None of the 1 082 isolates was compatible to Pm21 and less than 20.0%were virulent to the genotype carrying Pm13. In contrast, the virulence frequencies of each population was more than 50.0%to differentials carrying Pm1a, Pm3b, Pm3c, Pm3f, Pm5a, Pm6 and Pm8. In total, 1 028 pathotypes were detected, of which 984 were unique. Phenotypic diversity indices revealed a high level of diversity within populations. Genetic distance between different populations correlated signiifcantly with geographical distance （R2=0.494, P 0.001）. In addition, isolates from Xinjiang appear to form a separate group. Signiifcant positive or negative associations between alleles at pairs of virulence loci were detected in 57 allele pairs to Pm genes. Virulence and diversity of the 8 populations suggested that varieties with effective resistance gene combinations should be developed at a regional level.展开更多
The Helicobacter pylori(H. pylori) infection is a determinant factor in gastric cancer(GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cyt...The Helicobacter pylori(H. pylori) infection is a determinant factor in gastric cancer(GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cytokines such as interleukin(IL)-1β, IL-1 Ra, IL-8, IL-10 and tumor necrosis factor-α play important roles in the host immune system response to the pathogen, in the development of gastric mucosal lesions and in cell malignant transformation. Therefore, these host factors are crucial in neoplastic processes. Certain polymorphisms in genes that encode these cytokines have been associated with an increased risk of GC. On the other hand, various virulence factors found in distinct H. pylori bacterial strains, including cytotoxinassociated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and blood group antigen binding adhesin, have been associated with the pathogenesis of different gastric diseases. The virulent factors mentioned above allow the successful infection by the bacterium and play crucial roles in gastric mucosa lesions, including malignant transformation. Moreover, the role of host polymorphisms and bacterial virulence factors in gastric carcinogenesis seems to vary among different countries and populations. The identification of host and bacterium factors that are associated with an increased risk of GC development may be useful in determining the prognosis of infection in patients, what could help in clinical decision-making and in providing of an optimized clinical approach.展开更多
AIM： To characterize and compare genotype profiles of H pylori strains isolated from patients with chronic gastritis and duodenal ulcer in western part of Turkey. METHODS： A total of 46 patients [30 chronic gastrit...AIM： To characterize and compare genotype profiles of H pylori strains isolated from patients with chronic gastritis and duodenal ulcer in western part of Turkey. METHODS： A total of 46 patients [30 chronic gastritis （CG） and 16 duodenal ulcer （DU）] who had undergone endoscopy because of dyspeptic complaints were studied. The antral biopsy specimens were evaluated for the presence of Hpylori by rapid urease test and culture, and the genotype profiles were determined by real-time PCR. RESULTS： The cagA gene was observed in 43 （93.5%） isolates. The vacA s1m2 genotype was the predominant subtype, found in 63.3% and 68.7% of isolates in patients with CG and DU, respectively. Twenty （66.6%） isolates from patients with CG were iceA2 positive while the iceA1 was predominant in those with DU （68.8%）. In terms of the association of the ice,4 alleles to other genes, both alleles were significantly associated with the cagA vacA slm2 genotype. CONCLUSION： The prevalent circulating genotypes in CG and DU were cagA vacA slm2 iceA2 and cagA vacA slm2 iceA1 genotype, respectively. It was found that cagA vacA slm2 genotype seems to be common virulence factors in both CG and DU while iceA alleles show specificity for gastroduodenal pathologies in this study.展开更多
By investigating occurrence of Phytophthora root rot in fields and isolating P.sojae fromdiseased plants and soils, the distribution of P.sojae in China was surveyed. In addition tonortheast region, P.sojae existed in...By investigating occurrence of Phytophthora root rot in fields and isolating P.sojae fromdiseased plants and soils, the distribution of P.sojae in China was surveyed. In addition tonortheast region, P.sojae existed in Huanghe-Huaihe basin and Yangtze basin too. Eighty- threeisolates of P.sojae isolated from different areas were identified on virulence using 13differential soybean cultivars, abundant virulence diversity was found in P.sojae. The greaterdiversity in virulence of P.sojae was in isolates from soil than from plants. And the greatestvirulence diversity of P.sojae was found in Yangtze basin.展开更多
AIM To evaluate the association between virulence factor status and antibiotic resistance in Helicobacter pylori(H. pylori)-infected patients in Ireland. METHODS DNA was extracted from antral and corpus biopsies obtai...AIM To evaluate the association between virulence factor status and antibiotic resistance in Helicobacter pylori(H. pylori)-infected patients in Ireland. METHODS DNA was extracted from antral and corpus biopsies obtained from 165 H. pylori-infected patients. Genotyping for clarithromycin and fluoroquinolone-mediating mutations was performed using the Genotype Helico DR assay. cag A and vac A genotypes were investigated using PCR. RESULTS Primary, secondary and overall resistance rates for clarithromycin were 50.5%(n = 53/105), 78.3%(n = 47/60) and 60.6%(n = 100/165), respectively. Primary, secondary and overall resistance rates for fluoroquinolones were 15.2%(n = 16/105) and 28.3%(n = 17/60) and 20%(n = 33/165), respectively. Resistance to both antibiotics was 12.4%(n = 13/105) in treatment-na?ve patients, 25%(n = 15/60) in those previously treated and 17%(n = 28/165) overall. A cag A-positive genotype was detected in 22.4%(n = 37/165) of patient samples. The dominant vac A genotype was S1/M2 at 44.8%(n = 74/165), followed by S2/M2 at 26.7%(n = 44/165), S1/M1 at 23.6%(n = 39/165) and S2/M1 at 4.8%(n = 8/165). Primary clarithromycin resistance was significantly lower in cag A-positive strains than in cag A-negative strains [32%(n = 8/25) vs 56.3%(n = 45/80); P = 0.03]. Similarly, in patients infected with more virulent H. pylori strains bearing the vac A s1 genotype, primary clarithromycin resistance was significantly lower than in those infected with less virulent strains bearing the vac A s2 genotype, [41%(n = 32/78) vs 77.8%(n = 21/27); P = 0.0001]. No statistically significant association was found between primary fluoroquinolone resistance and virulence factor status.CONCLUSION Genotypic H. pylori clarithromycin resistance is high and cag A-negative strains are dominant in our population. Less virulent(cag A-negative and vac A S2-containing) strains of H. pylori are associated with primary clarithromycin resistance.展开更多
文摘Objective:To analyse the prevalence of serotypes,antibiotic resistance,and virulence genes of Group B Streptococcus(GBS)strains isolated from pregnant women at 35-37 weeks of gestation in Ho Chi Minh City,Vietnam,from January 2022 to January 2023.Methods:GBS strains were isolated through selective culture methods and confirmed by PCR.Serotyping,virulence gene detection,and antibiotic susceptibility testing were performed using PCR,gel electrophoresis techniques and Kirby-Bauer test.Results:Totally,61 GBS isolated from 300 participants have been identified including seven GBS serotypes(Ⅰa,Ⅰb,Ⅱ,Ⅲ,Ⅳ,Ⅴ,andⅥ).SerotypesⅦ,Ⅷ,andⅨwere not detected in the study population.Antibiotic resistance patterns varied:13.1%of isolates were fully susceptible,while the majority showed multi-drug resistance,with 34.4%resistant to three antibiotics.SerotypeⅠa demonstrated high susceptibility(35.7%),while serotypeⅢshowed extensive resistance,with 87.5%being resistant to at least three antibiotics.All strains are susceptible to vancomycin andβ-lactams susceptibility also remained high,but resistance to clindamycin,erythromycin,and tetracycline was high(>65%).The virulence genes scpB,cylB,fbsB,and cfb were highly prevalent(90%-100%),indicating their potential for vaccine and diagnostic development.Conclusions:Our findings provide valuable insights into GBS serotypes,resistance,and virulence factors,contributing to community monitoring,preventive measures,diagnostics,and vaccine development.However,the limited sample size necessitates further research.
基金supported by National Natural Science Foundation of China,China(32170102)Natural Science Foundation of Tianjin(21JCYBJC01420)the Fundamental Research Funds for the Central Universities(63233050)。
文摘Objective Pseudomonas aeruginosa(P.aeruginosa)is a prevalent pathogenic bacterium involved in meningitis;however,the virulence factors contributing to this disease remain poorly understood.Methods The virulence of the P.aeruginosa A584,isolated from meningitis samples,was evaluated by constructing in vitro blood-brain barrier and in vivo systemic infection models.qPCR,whole-genome sequencing,and drug efflux assays of A584 were performed to analyze the virulence factors.Results Genomic sequencing showed that A584 formed a phylogenetic cluster with the reference strains NY7610,DDRC3,Pa58,and Pa124.Its genome includes abundant virulence factors,such as hemolysin,the Type IV secretion system,and pyoverdine.A584 is a multidrug-resistant strain,and its wide-spectrum resistance is associated with enhanced drug efflux.Moreover,this strain caused significantly more severe damage to the blood-brain barrier than the standard strain,PAO1.qPCR assays further revealed the downregulation of the blood-brain barrier-associated proteins Claudin-5 and Occludin by A584.During systemic infection,A584 exhibited a higher capacity of brain colonization than PAO1(37.1×10^(6) CFU/g brain versus 2.5×10^(6) CFU/g brain),leading to higher levels of the proinflammatory factors IL-1βand TNF-α.Conclusion This study sheds light on the virulence factors of P.aeruginosa involved in meningitis.
基金supported by Research on Breeding and Healthy Breeding Technology of Xueyu White Chicken(mating line)in Tibet Science and Technology Program(XZ202101ZY0002N)the National Key R&D Program Project(2022YFD1600902-4)Sichuan Province Regional Innovation Cooperation Project(2023YFQ0050)。
文摘Bacterial infections of avian embryos can lead to an increase in embryo mortality,and the proliferation of antimicrobial-resistant bacteria aggravates the situation.A low hatching rate also poses a challenge to the population of artificially bred Crested Ibises(Nipponia nippon).This study aims to determine the potential association between bacterial infection and the death of Crested Ibis embryos,and whether there is convergence between antimicrobial resistance and virulence in strain.In this study,13 Escherichia coli and 12 Proteus mirabilis isolates were recovered from dead Crested Ibis embryos.The pathogenicity examination confirmed the pathogenicity of all isolates,and multiple virulence genes detected by PCR-sequencing demonstrated the presence of irp2 and iuc D(100%),fim C and iss(92.31%)in E.coli,and uca A(58.33%)in P.mirabilis.Antimicrobial susceptibility test demonstrated that isolates were mainly resistant to amoxicillin(E.coli:76.92%,P.mirabilis:91.67%),cefazolin(E.coli:76.92%,P.mirabilis:91.67%),oxytetracycline(E.coli:92.31%,P.mirabilis:75.00%)and sulfamethoxazole-trimethoprim(E.coli:53.85%,P.mirabilis:33.33%),and more than 30%of isolates showed multidrug-resistance(MDR).Further analyses detected extended-spectrumβ-lactamase(ESBL)genes,of which blaTEM-1(E.coli:100%,P.mirabilis:100%)had the highest frequency,followed by the blaCTX-M-55(E.coli:92.31%,P.mirabilis:50%),blaCTX-M-14(E.coli:76.92%,P.mirabilis:33.33%),blaCTX-M-65(E.coli:15.38%,P.mirabilis:16.67%),and all isolates were negative for blaSHV and blaOXA.Pearson's correlation analysis showed a positive correlation between the presence ofβ-lactam resistance and ESBL genes,while mainly negative correlations were observed between the presence of ESBL genes and virulence genes.Furthermore,the conjugation experiment and PFGE revealed that the isolates were primarily polyclonal,and there was horizontal transfer of resistance or virulence genes by plasmids.Based on the results,E.coli and P.mirabilis were responsible for embryonic mortality of the ibises in this study.The co-presence and co-transfer of ESBL genes and virulence genes can pose a potential threat to the health of the Crested Ibis,and measures such as prudent use of antimicrobials,and constant surveillance of resistance and pathogenicity,must be implemented at the Crested Ibis breeding base.
基金The Shandong Natural Science Foundation Youth Fund Project(ZR2022QC079,ZR2023QD024)provided funding for this work。
文摘Aeromonas veronii is considered an emerging food-borne pathogen associated with a significant threat to public health,distributed in various aquatic environments and products.Hanks-type serine/threonine kinases(STKs)play a critical role in the pathogenesis of pathogens.However,the function of A.veronii STKs is currently unclear.By constructing a markerless prk A in-frame deletion strain,Δprk A,we found that i)the colonies of theΔprk A strain were larger after 1 h of high temperature at 50℃compared with the wild-type strain TH0426 and the complementary strain C-prk A,and the number of viable bacteria of theΔprk A strain increased significantly;ii)theΔprk A strain significantly enhanced the adhesion ability to epithelioma papulosum cyprini(EPC)cells;iii)theΔprk A strain was significantly more virulent than the TH0426 strain,at both the cellular and animal levels;and iv)RNA-seq results showed a total of 984 differentially expressed genes(DEGs)between theΔprk A strain and the TH0426 strain,which were enriched in 70 Kyoto Encyclopedia of Genes and Genomes(KEGG)metabolic pathways,mainly involved in bacterial ribosomes,flagellar assembly,type Ⅱ secretion system(T2SS),and lipopolysaccharide metabolic pathways.Taken together,the findings of this study indicate that the Hanks-type STK Prk A negatively regulates several biological processes,such as the temperature tolerance and virulence of A.veronii.The results of this study provide an important reference for further elucidation of the pathogenesis of A.veronii.
文摘Helicobacter pylori infection represents a widespread chronic condition with varying prevalence influenced by race, ethnicity, and geography. The severity of H. pylori-associated diseases is determined by an array of virulence factors. Although extensive studies have been conducted globally, data on the distribution of Helicobacter pylori virulence genes in Libya remain limited, constraining insights into the pathogenicity of local strains and hindering the development of targeted interventions. This study aimed to evaluate the prevalence of H. pylori infection, characterize essential virulence genes [vacA variants (s1/s2, m1/m2), cagA, and iceA1], and examine their association with gastroduodenal diseases among Libyan patients. Gastric biopsies from 144 participants were analyzed using polymerase chain reaction (PCR) assays, and risk factor data were collected via questionnaires. H. pylori was detected in 63.2% of samples by PCR. The vacA gene was present in 84.6% of cases, cagA in 58.2%, and iceA1 in 29.7%. Among vacA variants, s1 allele was most common (53.2%), followed by m1 (42.9%), m2 (37.7%), and s2 (13%) alleles. Significant associations were identified between specific virulence genes and the development of gastroduodenal diseases, highlighting their role in pathogenicity. This investigation is one of Libya’s first comprehensive assessments of H. pylori virulence factors, addressing a critical epidemiological gap. The high prevalence of virulence genes suggests their potential as disease biomarkers. These findings contribute to a deeper understanding of H. pylori pathogenicity within the Libyan population and establish a basis for future clinical interventions and public health strategies to manage and prevent H. pylori-associated diseases in Libya and comparable regions.
基金supported by the National Natural Science Foundation of China(32072461)the Open Foundation of Shaanxi Key Laboratory of Plant Nematology,China(2021-SKL-01).
文摘The velvet protein family serves as a crucial factor in coordinating development and secondary metabolism in numerous pathogenic fungi.However,no previous research has examined the function of the velvet protein family in Fusarium oxysporum f.sp.niveum(FON),a pathogen causing a highly destructive disease in watermelon.In this study,∆fovel1 and∆folae1 deletion mutants and∆fovel1-C and∆folae1-C corresponding complementation mutants of FON were validated.Additionally,the phenotypic,biochemical,and virulence effects of the deletion mutants were investigated.Compared to the wild-type strains,the∆fovel1 and∆folae1 mutants exhibited altered mycelial phenotype,reduced conidiation,and decreased production of bikaverin and fusaric acid.Furthermore,their virulence on watermelon plant roots significantly decreased.All these alterations in mutants were restored in corresponding complementation strains.Notably,yeast two-hybrid results demonstrated an interaction between FoVel1 and FoLae1.This study reveals that FoVEL1 and FoLAE1 play essential roles in secondary metabolism,conidiation,and virulence in FON.These findings enhance our understanding of the genetic and functional roles of VEL1 and LAE1 in pathogenic fungi.
基金Supported by Agricultural Achievement Transformation Project of the Ministry of Science and Technology(2012GB2A200045)China Postdoctoral Science Foundation(20100470565)+1 种基金Science and Technology Support Program of Hebei Province(10960408D)Science and Technology Development Project of Qinhuangdao City(201101A182)~~
文摘[Objective] This study aimed to explore the presence of three causative genes Colv,Stxs and HlyE of the pathogenic E.coli from chickens,pigs and food.[Method] By using 44 E.coli strains from chickens,24 from pigs and 26 from food as the experimental materials,virulence genes Colv,Stxs（stx2,stx2e） and HlyE were detected with polymerase chain reaction（PCR） method.[Result] Among all the E.coli strains,the detection rate of Colv was 25% from chickens,4.2% from pigs,and 0 from food;the detection rate of Stx2（Stx2e） from all E.coli strains was 0;the detection rate of HlyE was 2.27% from chickens,0 from pigs,and 11.5% from food.[Conclusion] Virulence gene Colv shows relatively high carrying rate in E.coli from chickens and pigs;HlyE also shows a certain degree of presence in E.coli from chickens and food.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest (Grant No. 201203014)Sichuan Program for Major Crop,Poultry and Livestock Breeding,China (Grant No.2012YZGG-25-3)
文摘A total of 638 isolates of rice blast （Magnaporthe oryzae） were isolated in 2002-2009 from different rice varieties in different regions of Sichuan, China and inoculated onto seven rice varieties （Lijiangxintuanheigu, IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1） to differentiate the virulence types of the fungus and trace the changes. The virulence to the seven varieties was respectively scored at 1, 2, 4, 8, 16, 32 and 64. The total scores of individual M. grisea isolates which were the sum of scores infecting differential varieties could, in turn, be used for the nomenclature of the virulence types due to their accordance to the special virulence patterns. The 638 tested isolates were then differentiated into 56 different virulence types. Type 15 virulent to Lijiangxintuanheigu, IR24 and Minghui 63, and Type 127 virulent to all of the seven varieties were the most dominant virulence types respectively with the occurrence frequencies of 15.99% and 15.83%. Type 19 and other seven virulence types were not monitored during 2002-2009. Type 15 was the predominant virulence type in 2002, 2003, 2004 and 2007, whereas Type 127 had been the most dominant virulence type after 2005 except for the year 2007 when the province underwent severe drought. Five hundred and seven out of the 638 tested isolates were virulent to Minghui 63, and 89.58% of the 384 isolates virulent to either Duohui 1, Chenghui 448 or Neihui 99-14 were virulent to Minghui 63, which indicated the impact of the extensive plantation of hybrid rice Minghui 63 as the restorer line on the virulence evolution of M. oryzae in Sichuan. The virulence pattern of the dominant virulence types suggested that the acquiring of virulence to all the major resistant restorer lines was the main routes of the evolution in virulence of M. oryzae to hybrid rice in Sichuan. The virulence frequencies of the 638 tested isolates to IR24, Minghui 63, Duohui 1, Chenghui 448, Neihui 99-14 and RHR-1 were respectively 74.6%, 79.5%, 73.8%, 37.0%, 39.0% and 40.4%. The analysis for the sources of the different virulence type isolates indicated the pathogen on the newly released resistant varieties were stronger than conventional rice varieties which had become susceptible in the field since 1980s.
文摘Fungal pathogen of asparagus stem blight was isolated. No significant genetic difference was detected among the three strains with 492 bp long ITS1-5.8S-ITS2 sequence. It was then identified through colony growth, conidia morphology, and molecular characterization. The physiological response to oxidation and osmosis stress, and virulence to Asparagus officinalis L. were analyzed. The results showed that the pathogen causing asparagus stem blight for A. officinalis L. in Jiangxi Province is Phomopsis asparagri (Sacc.) Bubák. Under pure culture conditions, the conidia were oval-shaped (α-type), with colorless single spore and single nucleus, containing 0-2 oil balls. Its vegetative growth rate was higher when cultured on 0.2 × potato dextrose agar (0.2 × PDA) medium than that on oatmeal agar (OA) medium. However, the pycnidia appeared earlier on OA medium than on 0.2 earlier PDA medium. The vegetative growth rate was depressed under oxidation (H2O2) or osmosis (NaCl) stress conditions, and totally inhibited under 7 mmol/L H2O2 or 2.4 mol/L NaCl. All the strains caused typical pathogenic symptoms to Asparagus officinalis L. at 7 days-post-inoculation (dpi) with conidia.
文摘Helicobacter pylori(H.pylori)is one of the most important human pathogens,infecting approximately half of the global population.Despite its high prevalence,only a subset of H.pylori infected individuals develop serious gastroduodenal pathology.The pathogenesis of H.pylori infection and disease outcome is thus thought to be mediated by an intricate interplay between host,environmental and bacterial virulence factors.H.pylori has adapted to the harsh milieu of the human stomach through possession of various virulence genes that enable survival of the bacteria in the acidic environment,movement towards the gastric epithelium,and attachment to gastric epithelial cells.These virulence factors enable successful colonization of the gastric mucosa and sustain persistent H.pylori infection,causing chronic inflammation and tissue damage,which may eventually lead to the development of peptic ulcers and gastric cancer.Numerous studies have focused on the prevalence and role of putative H.pylori virulence genes in disease pathogenesis.While several virulence factors with various functions have been identified,disease associations appear to be less evident,especially among different study populations.This review presents key findings on the most important H.pylori virulence genes,including several bacterial adhesins and toxins,in children and adults,and focuses on their prevalence,clinical significance and potential relationships.
文摘Helicobacter pylori(H. pylori) is a model organism for understanding host-pathogen interactions and infection-mediated carcinogenesis. Gastric cancer and H. pylori colonization indicates the strong correlation. The progression and exacerbation of H. pylori infection are influenced by some factors of pathogen and host. Several virulence factors involved in the proper adherence and attenuation of immune defense to contribute the risk of emerging gastric cancer, therefore analysis of them is very important. H. pylori also modulates inflammatory and autophagy process to intensify its pathogenicity. From the host regard, different genetic factors particularly affect the development of gastric cancer. Indeed, epigenetic modifications, Micro RNA and long non-coding RNA received more attention. Generally, various factors related to pathogen and host that modulate gastric cancer development in response to H. pylori need more attention due to develop an efficacious therapeutic intervention. Therefore, this paper will present a brief overview of host-pathogen interaction especially emphases on bacterial virulence factors, interruption of host cellular signaling, the role of epigenetic modifications and non-coding RNAs.
基金Supported by The Polish Ministry of Science and Higher Education Grants No. 2 PO5A 094 29, 3 P05E 091 25, N N402 0861 and N N401 144638
文摘AIM: To determine the features of Enterococcus that contribute to the development and maintenance of the inflammatory process in patients with inflammatory bowel disease (IBD). METHODS: Multiplex polymerase chain reaction (PCR) was applied to assess the presence of genes that encode virulence factors [surface aggregating protein (asa1), gelatinase (gelE), cytolysin (cylA), extracellular surface protein (esp) and hyaluronidase (hyl)] in the genomic DNA of 28 strains of Enterococcus isolated from the intestinal tissues of children with IBD (n =16) and of children without IBD (controls; n = 12). Additionally, strains with confirmed presence of the gelE gene were tested by PCR for the presence of quorum sensing genes (fsrA, fsrB, fsrC) that control the gelatinase production. Gelatinase activity was tested on agar plates containing 1.6% gelatin. We also analysed the ability of Enterococcus strains to release and decompose hydrogen peroxide (using Analytical Merckoquant peroxide test strips) and tested their ability to adhere to Caco-2 human gut epithelium cells and form biofilms in vitro. RESULTS: A comparison of the genomes of Enterococcus strains isolated from the inflamed mucosa of patients with IBD with those of the control group showed statistically significant differences in the frequency of theasa1 gene and thegelE gene. Furthermore, the cumulative occurrence of different virulence genes in the genome of a single strain ofEnterococcus isolated from the IBD patient group is greater than in a strain from the control group, although no significant difference was found. Statistically significant differences in the decomposition of hydrogen peroxide and adherence to the Caco-2 epithelial cell line between the strains from the patient group and control group were demonstrated. The results also showed that profuse biofilm production was more frequent amongEnterococcus strains isolated from children with IBD than in control strains. CONCLUSION: Enterococcus strains that adhere strongly to the intestinal epithelium, form biofilms and possess antioxidant defence mechanisms seem to have the greatest influence on the inflammatory process.
基金supported by grants from the National Key Research and Development Program(2018YFC0840402)National Natural Science Foundation of China(31941002)+2 种基金Special Fund for Basic Scientific Research of Chinese Academy of Agricultural Sciences (Y2019YJ07-01)Science and technology innovation engineering major scientific research program of Chinese Academy of Agricultural Sciences (CAASZDRW202006-03)State Key Laboratory of Veterinary Etiological Biology Major achievements cultivation project of Chinese Academy of Agricultural Sciences (SKLVEB2020CGPY02)。
文摘African swine fever virus(ASFV)is the etiological agent of African swine fever(ASF),an often lethal disease in domestic and wild pigs.ASF represents a major threat to the swine industry worldwide.Currently,no commercial vaccine is available because of the complexity of ASFV or biosecurity concerns.Live attenuated viruses that are naturally isolated or genetically manipulated have demonstrated reliable protection against homologous ASFV strain challenge.In the present study,a mutant ASFV strain with the deletion of ASFV MGF-110-9L(ASFV-D9L)was generated from a highly virulent ASFV CN/GS/2018 parental strain,a genotypeⅡASFV.Relative to the parental ASFV isolate,deletion of the MGF-110-9L gene significantly decreased the ability of ASFV-D9L to replicate in vitro in primary swine macrophage cell cultures.The majority of animals inoculated intramuscularly with a low dose of ASFV-D9L(10 HAD50)remained clinically normal during the 21-day observational period.Three of five ASFV-D9L-infected animals displayed low viremia titers and low virus shedding and developed a strong virus-specific antibody response,indicating partial attenuation of the ASFV-D9L strain in pigs.The findings imply the potential usefulness of the ASFV-D9L strain for further development of ASF control measures.
基金Supported by The Italian Ministry of Health, Programma per la Ricerca Sanitaria 2007, Programma Strategico, Salute della donna/Area materno infantile, No. RFPS-2007-4-638281
文摘AIM: To better understand the pathogenic role of Helicobacter pylori (H. pylori) in pre-eclampsia (PE), and whether it is associated or not with fetal growth retardation (FGR). METHODS: Maternal blood samples were collected from 62 consecutive pregnant women with a diagnosis of PE and/or FGR, and from 49 women with uneventful pregnancies (controls). Serum samples were evaluated by immunoblot assay for presence of specific antibodies against H. pylori antigens [virulence: cytotoxin-associated antigen A (CagA); ureases; heat shock protein B; flagellin A; persistence: vacuolating cytotoxin A (VacA)]. Maternal complete blood count and liver enzymes levels were assessed at delivery by an automated analyzer. RESULTS: A significantly higher percentage of H. pyloriseropositive women were found among PE cases (85.7%) compared to controls (42.9%, P < 0.001). There were no differences between pregnancies complicated by FGR without maternal hypertension (46.2%) and controls. Importantly, persistent and virulent infections (VacA/ CagA seropositive patients, intermediate leukocyte blood count and aspartate aminotransferase levels) were exclusively associated with pre-eclampsia complicated by FGR, while virulent but acute infections (CagA positive/ VacA negative patients, highest leukocyte blood count and aspartate aminotransferase levels) specifically correlated with PE without FGR. CONCLUSION: Our data strongly indicate that persistent and virulent H. pylori infections cause or contribute to PE complicated by FGR, but not to PE without feto-placental compromise.
基金Supported by the Natural Science Foundation of Fujian Province,China,No.95A003
文摘AIM: To explore the virulence and the potential pathogenicity of coccoid Helicobacter pylori (H. pylori) transformed from spiral form by exposure to antibiotic. METHODS: Three strains of H. pylori, isolated from gastric biopsy specimens of confirmed peptic ulcer, were converted from spiral into coccoid from by exposure to metronidazole. Both spiral and coccoid form of H. pylori were tested for the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells, and the differences of the protein were analysed by SDS-PAGE and Western blot. The mutation of the genes including ureA, ureB,hpaA, vacA and cagA, related with virulence, was detected by means of PCR and PCR-SSCP. RESULTS: In the coccoid H. pylori,the urease activity, the adherence to Hep-2 cells and the vacuolating cytotoxicity to Hela cells all decreased. In strain F44, the rate and index of adherence reduced from 70.0% +/- 5.3% to 33% +/- 5.1% and from 2.6 +/- 0.4 to 0.96 +/- 0.3 (P 【 0.01), respectively. The invasion of coccoid H. pylori into Hep-2 cell could be seen under electronmicroscope. SDS-PAGE showed that the content of the protein with the molecular weight over Mr 74000 decreased, and the hybriditional signal in band M(r) 125000 weakened, while the band M(r)110000 and M(r)63000 strengthened in coccoid H.pylori as shown in Western blot. The results of PCR were all positive, and PCR-SSCP indicated that there may exist the point mutation in gene hpaA or vacA. CONCLUSION: The virulence and the proteins with molecular weight over M(r)74000 in coccoid H.pylori decrease, but no deletion exists in amplification fragments from ureA, ureB, hpaA, vacA and cagA genes, suggesting that coccoid H.pylori may have potential pathogenicity.
基金supported by the National Basic Research Program of China (2013CB127700)the Special Fund for Agro-Scientific Research in the Public Interest, China (201303016)
文摘Wheat powdery mildew, caused by Blumeria graminis f. sp. tritici, is an important disease in China. To characterize the virulence and diversity of the pathogen, 1 082 isolates were obtained from 8 major wheat-growing regions during the spring growing season in 2011. The virulence test was performed by inoculation on detached leaves of 22 differential lines with known Pm genes. Frequencies of virulence on these genotypes ranged from 0 to 97.4%. None of the 1 082 isolates was compatible to Pm21 and less than 20.0%were virulent to the genotype carrying Pm13. In contrast, the virulence frequencies of each population was more than 50.0%to differentials carrying Pm1a, Pm3b, Pm3c, Pm3f, Pm5a, Pm6 and Pm8. In total, 1 028 pathotypes were detected, of which 984 were unique. Phenotypic diversity indices revealed a high level of diversity within populations. Genetic distance between different populations correlated signiifcantly with geographical distance （R2=0.494, P 0.001）. In addition, isolates from Xinjiang appear to form a separate group. Signiifcant positive or negative associations between alleles at pairs of virulence loci were detected in 57 allele pairs to Pm genes. Virulence and diversity of the 8 populations suggested that varieties with effective resistance gene combinations should be developed at a regional level.
文摘The Helicobacter pylori(H. pylori) infection is a determinant factor in gastric cancer(GC) development. However, the infection outcomes are variable and depend on both host and bacterial characteristics. Some host cytokines such as interleukin(IL)-1β, IL-1 Ra, IL-8, IL-10 and tumor necrosis factor-α play important roles in the host immune system response to the pathogen, in the development of gastric mucosal lesions and in cell malignant transformation. Therefore, these host factors are crucial in neoplastic processes. Certain polymorphisms in genes that encode these cytokines have been associated with an increased risk of GC. On the other hand, various virulence factors found in distinct H. pylori bacterial strains, including cytotoxinassociated antigen A, vacuolating cytotoxin, duodenal ulcer promoting gene A protein, outer inflammatory protein and blood group antigen binding adhesin, have been associated with the pathogenesis of different gastric diseases. The virulent factors mentioned above allow the successful infection by the bacterium and play crucial roles in gastric mucosa lesions, including malignant transformation. Moreover, the role of host polymorphisms and bacterial virulence factors in gastric carcinogenesis seems to vary among different countries and populations. The identification of host and bacterium factors that are associated with an increased risk of GC development may be useful in determining the prognosis of infection in patients, what could help in clinical decision-making and in providing of an optimized clinical approach.
基金Supported by a grant from Turkish Goverment State Planning Organization, No. DPT-2003K120950
文摘AIM： To characterize and compare genotype profiles of H pylori strains isolated from patients with chronic gastritis and duodenal ulcer in western part of Turkey. METHODS： A total of 46 patients [30 chronic gastritis （CG） and 16 duodenal ulcer （DU）] who had undergone endoscopy because of dyspeptic complaints were studied. The antral biopsy specimens were evaluated for the presence of Hpylori by rapid urease test and culture, and the genotype profiles were determined by real-time PCR. RESULTS： The cagA gene was observed in 43 （93.5%） isolates. The vacA s1m2 genotype was the predominant subtype, found in 63.3% and 68.7% of isolates in patients with CG and DU, respectively. Twenty （66.6%） isolates from patients with CG were iceA2 positive while the iceA1 was predominant in those with DU （68.8%）. In terms of the association of the ice,4 alleles to other genes, both alleles were significantly associated with the cagA vacA slm2 genotype. CONCLUSION： The prevalent circulating genotypes in CG and DU were cagA vacA slm2 iceA2 and cagA vacA slm2 iceA1 genotype, respectively. It was found that cagA vacA slm2 genotype seems to be common virulence factors in both CG and DU while iceA alleles show specificity for gastroduodenal pathologies in this study.
基金supported by the National Natural Science Foundation of China(39970497)Nationa1 Basic Work Program of China(2001BA509B0608).
文摘By investigating occurrence of Phytophthora root rot in fields and isolating P.sojae fromdiseased plants and soils, the distribution of P.sojae in China was surveyed. In addition tonortheast region, P.sojae existed in Huanghe-Huaihe basin and Yangtze basin too. Eighty- threeisolates of P.sojae isolated from different areas were identified on virulence using 13differential soybean cultivars, abundant virulence diversity was found in P.sojae. The greaterdiversity in virulence of P.sojae was in isolates from soil than from plants. And the greatestvirulence diversity of P.sojae was found in Yangtze basin.
基金Supported by the Health Research Board(HRA-POR-2014-526)
文摘AIM To evaluate the association between virulence factor status and antibiotic resistance in Helicobacter pylori(H. pylori)-infected patients in Ireland. METHODS DNA was extracted from antral and corpus biopsies obtained from 165 H. pylori-infected patients. Genotyping for clarithromycin and fluoroquinolone-mediating mutations was performed using the Genotype Helico DR assay. cag A and vac A genotypes were investigated using PCR. RESULTS Primary, secondary and overall resistance rates for clarithromycin were 50.5%(n = 53/105), 78.3%(n = 47/60) and 60.6%(n = 100/165), respectively. Primary, secondary and overall resistance rates for fluoroquinolones were 15.2%(n = 16/105) and 28.3%(n = 17/60) and 20%(n = 33/165), respectively. Resistance to both antibiotics was 12.4%(n = 13/105) in treatment-na?ve patients, 25%(n = 15/60) in those previously treated and 17%(n = 28/165) overall. A cag A-positive genotype was detected in 22.4%(n = 37/165) of patient samples. The dominant vac A genotype was S1/M2 at 44.8%(n = 74/165), followed by S2/M2 at 26.7%(n = 44/165), S1/M1 at 23.6%(n = 39/165) and S2/M1 at 4.8%(n = 8/165). Primary clarithromycin resistance was significantly lower in cag A-positive strains than in cag A-negative strains [32%(n = 8/25) vs 56.3%(n = 45/80); P = 0.03]. Similarly, in patients infected with more virulent H. pylori strains bearing the vac A s1 genotype, primary clarithromycin resistance was significantly lower than in those infected with less virulent strains bearing the vac A s2 genotype, [41%(n = 32/78) vs 77.8%(n = 21/27); P = 0.0001]. No statistically significant association was found between primary fluoroquinolone resistance and virulence factor status.CONCLUSION Genotypic H. pylori clarithromycin resistance is high and cag A-negative strains are dominant in our population. Less virulent(cag A-negative and vac A S2-containing) strains of H. pylori are associated with primary clarithromycin resistance.
