Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Ente...Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.展开更多
Antimicrobial resistance(AMR)has become a critical global public health challenge in the 21st century.Since the initial isolation of a blaNDM-1-carrying and carbapenem-resistant Klebsiella pneumoniae from an Indian ho...Antimicrobial resistance(AMR)has become a critical global public health challenge in the 21st century.Since the initial isolation of a blaNDM-1-carrying and carbapenem-resistant Klebsiella pneumoniae from an Indian hospital in 2009[1],the escalating prevalence of New Delhi metallo-β-lactamase(NDM)-encoding genes(blaNDM)has transformed carbapenem resistance into a worldwide phenomenon,transcending national and regional boundaries[2].Up to 90 distinct NDM variants have been reported globally according to the NCBI GenBank Pathogens database.Plasmidmediated horizontal gene transfer(HGT),which occurs both within and across bacterial species,has significantly accelerated the global dissemination of blaNDM-related genes and the associated resistance[3].Carbapenem-resistant pathogens were responsible for 200,000 deaths globally in 2019[4].Although NDM-1 has been relatively well characterized[5],the epidemiological profiles of other NDM variants require continued surveillance and indepth investigation.The novel NDM-9 variant(GenBank accession no.KC999080)was first identified in 2013 from a clinically significant isolate of Klebsiella pneumoniae ST107 strain PPH1303 with a high level of resistance to carbapenems recovered from the urine culture of a pediatric patient in Beijing,China,who had acute lymphocytic leukemia and had undergone allogeneic stem cell transplantation[6].展开更多
Background:Fibrosis constitutes a significant pathophysiological mechanism in the clinical progression of benign prostatic hyperplasia(BPH)and represents a contributing factor to the ineffectiveness of prevailing phar...Background:Fibrosis constitutes a significant pathophysiological mechanism in the clinical progression of benign prostatic hyperplasia(BPH)and represents a contributing factor to the ineffectiveness of prevailing pharmacological treatments.Emerging evidence suggests a close association between microbial presence and the development of fibrosis.Nonetheless,the potential involvement of microbes within prostatic tissue in the pathogenesis of BPH and prostatic fibrosis,along with the underlying mechanisms,remains unexplored.Methods:Utilizing immunohistochemistry and microbial sequencing,we analyzed the microbes of prostate tissues from BPH patients with different degrees of prostate fibrosis and found that Salmonellaenterica(S.enterica)was enriched in the high degree of prostate fibrosis.We developed prostate cell and animal models infected with the lipopolysaccharide of S.enterica(S.e-LPS)to assess its impact on prostate fibrosis.To elucidate the underlying functional mechanisms,we employed molecular biology techniques,including RNA degradation assays,N6-methyladenosine(m6A)dot blotting,RNA immunoprecipitation,and m6A immunoprecipitation.Results:Microbial diversity differed between low-and high-fibrosis groups,with S.enterica showing the highest mean abundance among the 4 species that differed significantly.S.e-LPS was detected in S.enterica-rich prostate tissue and was found to significantly promote cell proliferation,cell contractility,lipid peroxidation,and the induction of ferroptosis.Animal experiments demonstrated that S.e-LPS infection led to pronounced hyperplasia of the prostatic epithelium,with epithelial thickness increasing to 1.57 times that of the sham group,and collagen fibrosis increasing to 2.84 times that of the sham group,thereby exacerbating prostatic tissue fibrosis in rats.Invitro experiments further revealed that S.e-LPS promoted prostate cell fibrosis by inducing ferroptosis.Mechanistically,it was determined that S.e-LPS regulates ferroptosis via AlkB homolog 5(ALKBH5)-mediated m6A modification,which affects the stability of glutathione peroxidase 4(GPX4)mRNA,thereby affecting prostatic fibrosis.Conclusion:The findings of this study suggest that S.enterica promotes prostatic fibrosis through ALKBH5-m6A-GPX4-mediated ferroptosis.This research offers novel insights for the development of new therapeutic targets and personalized strategies for the prevention and treatment of BPH from the perspectives of microbes and epigenetics.展开更多
Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in...Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in Mamakkal,Tamil Nadu.India.Both strains were grown in LB(Luria Bertani) medium supplemented with various concentration of NaCl(0.1- 0.7M) respectively.The effecl of osmolar stress was determined at molecular level by PCR using MCR 06 and MCR07 primers corresponding to ompR with chromosomal DNA of S.typhi SS3 and SS5 strains.Attenuation by osmolar stress results in deletion mutation of the.S.typhi slrains was determined by agglutination assays,precipitation method.SDS PAGE analysis and by animal models.Results:The 799 bp amplified ompR gene product from wild type S.typhi SS3 and SS5 illustrate the presence of virulent gene.Interestingly,there was only a 282 bp amplified product from S.typhi SS3 and SS5 grown in the presence of 0.5.0.6 and 0.7 M NaCl.This illustrates the occurrence of deletion mutation in ompR gene al high concentration of NaCl.Furthermore,both the wildtype and mutant S.typhi outer membrane SDS-PAGF.profile reveals the differences in the expression of ompF.ompC and ompA proteins.In mice,wild type and mutant strains lethal dose(LD_(50)) were determined.The mice died within 72 h when both the wild type strains were injected intraperitoneally with 3 log CFU-mL^(-1).When the mice were injected with the mutants in same dosage,no clinical symptoms were observed;whereas the serum antibodv litre was elicited within two weeks indicated that the mutants have the ability to induce protective humoral immune response.These results suggest that S.typhi SS3 and SS5 may bo used as good candidate strains for the development of live attenuated vaccine against salmonellosis.Conclusions:This study demonstrates that the S.typhi strains were allenualed and could be good vaccine candidates in future.展开更多
Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica...Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,展开更多
本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分...本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分泌物;动态污染研究表明:沙门氏菌能在姜块中迅速繁殖,显著提高姜块超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)的活性。该研究表明,沙门氏菌能以生姜为寄主存活。展开更多
Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Meth...Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Methods:The antibacterial activity of ethanolic extract of tulsi, 0.sanctum,leaf(TLE:500μg) for 23 S.typhi isolates was determined following agar diffusion. The C(30μg) and Tm(5μg) activity alone and in combination with TLE(250μg) was determined by disk diffusion.The zone diameter of inhibition(ZDI) for the agents was recorded, and growth inhibitory indices(Glls) were calculated.Results:The S.typhi isolates(n=23),which were resistant to both C(ZDI 6 mm) and Tm(ZDI 6 mm),had TLE(500μg) ZDIs 16-24 mm.The ZDIs of C and Tm were increased up to 15-21 mm and 17-23 mm,respectively,when TLE(250μg) was added to the C and Tm discs.The Glls ranged 0.789-1.235 and 0.894-1.352,due to combined activity against S.typhi isolates,of C and TLE and Tm and TLE.respeclivelv.Conclusions:The data suggest that TLE,in combination with C and Tm,had synergistic activity for S.typhi isolates, and hence O.sanclum is potential in combating S.typhi drug resistance,as well promising in the development of non-antibiotic drug for S.typhi infection.展开更多
Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene a...Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene and kanamycin gene were PCR amplified.Each of these DNA fragment was cloned into p GEM T-easy vector.The construct was confirmed by PCR and restriction digest.Results:PCR amplified 320,206 and 835 bp DNA fragments were subcloned into p ET-32 vector resulting with a plasmid called p ET-32-sip C up-kan-sip C down.Conclusions:The new plasmid(p ET-32-sip C up-kan-sip C down)is useful for genetic engineering and for future manipulation of S.typhimurium sip C gene.展开更多
Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The op...Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The open reading frame(ORF) 009 was identified as a toxin coding gene in the plasmid through introduction of translational termination codons in the ORF. Results: The stability function was located in a fragment that spanned nucleotides 5 766 to 6 828 in the linear plasmid genetic map. Ectopic expression of ORF009 in pBAD18 vector indicated ORF009 codes for a toxin. This fragment could stabilize plasmid pUC18 previously destabilized through mutation of the pcnB(plasmid copy number control) gene that codes for polyA polymerase. Majority of the cells expressing ORF009 were non-viable according to phase contrast microscopy. Conclusions: This study demonstrated that a linear plasmid fragment that carries a gene encoding a toxin possibly conferred stability to the parent plasmid. It was able to stabilize a multicopy plasmid of Escherichia coli.展开更多
Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major publi...Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major public health issue worldwide in the 1980s. The main causative food material of SE food poisoning is chicken eggs, and many outbreaks of food poisoning caused by chicken eggs occurred throughout the world. SE epidemics occurred in layer farms, and this was the main cause of SE-induced food poisoning in humans. The major subject of our epidemiological study described in this report is why SE-contaminated eggs became the main causative food. In this study, we focused on difference of molecular expression for farm-isolated SEs. That is because recent studies have demonstrated that O-antigen enlargement may be related to pathogenicity in mice as well as 22-kDa polypeptide-expression (SEp22). We have discovered that many SE strains isolated from chicken farms do not express SEp22, and a deficiency or decreased level of cellular antigen 0-12 in SE strains isolated from chicken farms was clarified in a report. Additionally, SEp22 was deficient in SE strains passaged through chickens, whereas SEp22 was expressed at a high level in SE strains passaged through mice. These findings suggest that SE infection and retention more effectively occur in layer farms than in other animal maintenance environments, which may be a basis of the epidemiological hypothesis to explain the high-levelproduction of SE-contaminated eggs (the presence of mice may be the basis of the retention of SE infection in layer farms, and this may also be the mechanism causing the high-level production of SE-contaminated eggs).展开更多
Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabdi...Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabditis elegans has proven to be a useful model to study infection dynamics of pathogenic bacteria, including Salmonella enterica, and its short lifespan makes it a powerful model system to assess the effect of organismal age on infection severity. In this study, we infected C. elegans with each of 6 serovars of S. enterica at 1, 3 or 5 days of worm age and monitored their survival. Worms infected with E. coli OP50 were used as a control. Infection with S. enterica resulted in a significant reduction in mean longevity relative to OP50 (p < 0.05);however, there was no significant effect of age on mean survival time regardless of the strain of bacteria used.展开更多
BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE S...BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.展开更多
Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with ...Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with Salmonella enterica serovar Enteritidis and Typhimurium, because fibroblast can be a target cell for Salmonella latent infection. It was found that both S. Enteritidis and S. Typhimurium were able to adhere and invade to swine fibroblasts. The proliferations in fibroblasts were different between each serovar. S. Enteritidis reached to the maximum at 24 hr after infection while S. Typhimurium did not. In addition, the decrease in the G<sub>0</sub>/G<sub>1</sub> phase cells and increase in G<sub>2</sub>/M phase cells on the fibroblast were observed by both Salmonella infection. Cell death including apoptosis in the cells was inhibited by the infection of Salmonella. These results suggest that nontyphoidal Salmonella can survive for the long term by modifying bacterial cell proliferation and preventing cell death of host cells.展开更多
<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica&...<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> serovars is a leading cause of human gastroenteritis, and the incidence of salmonellosis is constantly increasing, causing millions of infections and many deaths annually. The detection of the pathogen in optimal terms is an essential factor for reducing the impact on the human body. In this work</span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> SYBR Green I-based qPCR method of detection and quantifica<span>tion of </span></span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">was</span></span></span><span><span><span style="font-family:""> developed and validated. For detection o</span></span></span><span><span><span style="font-family:"">f </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> subsp.<i> </i></span></span></span><span><span><i><span style="font-family:""><i></span></i></span></span><span><span><i><span style="font-family:"">enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">, two pairs of primers were designed using publically available Primer-BLAST software. Primer efficiency was calculated <span>by establishing a standard curve. The specificity, sensitivity, accuracy, and</span> precision of PCR results were tested. Both primer pairs showed an acceptable performance, proving the developed techniques were sensitive, reliable and precise. The validated <span>qPCR technology has a good potential to replace the traditional culture method in microbial diagnosis.展开更多
We read the study conducted by Cui et al.published in China CDC Weekly with great interest,and would like to make comment on this matter(1).The report identified 31 Salmonella enterica serovar I 1,4,[5],12:i:-(S.I 1,4...We read the study conducted by Cui et al.published in China CDC Weekly with great interest,and would like to make comment on this matter(1).The report identified 31 Salmonella enterica serovar I 1,4,[5],12:i:-(S.I 1,4,[5],12:i:-)sequence type 8333(ST8333)genomes by the end of 2023 in the National Molecular Tracing Network for Foodborne Disease Surveillance database.The overall percentage of isolates of S.I 1,4,[5],12:i:-ST8333 remained low in their active monitoring between 2017 and 2023,and observed ST8333 in 2017.展开更多
Salmonella,a gram-negative bacterium from the Enterobacteriaceae family,is widely distributed in nature.To date,over 2600 serotypes have been identified.Salmonella enterica serovar Kentucky(S.Kentucky)is considered to...Salmonella,a gram-negative bacterium from the Enterobacteriaceae family,is widely distributed in nature.To date,over 2600 serotypes have been identified.Salmonella enterica serovar Kentucky(S.Kentucky)is considered to be a“super-resistant”strain of Salmonella in Europe and the USA and is a rare serotype in China.Clinical isolates are typically obtained from patients’fecal samples,with no previous reports of isolation from the eyes.Here,we report a case of isolation of S.Kentucky from the purulent aspirate of an orbital abscess during routine clinical practice.The infection was successfully managed by surgical excision of the primary lesion in combination with targeted antibiotic treatment.This case thus emphasizes the need for clinicians to select antibiotics based on antimicrobial susceptibility reports.展开更多
Introduction:Salmonella 4,[5],12:i:-,a globally emerging pathogen with multidrug resistance(MDR),is spreading in China.Nationwide data on the antimicrobial resistance(AMR)and genomic characteristics of Salmonella 4,[5...Introduction:Salmonella 4,[5],12:i:-,a globally emerging pathogen with multidrug resistance(MDR),is spreading in China.Nationwide data on the antimicrobial resistance(AMR)and genomic characteristics of Salmonella 4,[5],12:i:-from human sources in China are scarce.This study aimed to characterize the prevalence,genetic diversity,and AMR profiles of Salmonella 4,[5],12:i:-in China.Methods:All information,including geographical data,antimicrobial susceptibility test results,and whole-genome sequences,was extracted from the Chinese Pathogen Identification Network database from 2017 to 2023.Antimicrobial resistance phenotypes of 2,736 human-derived isolates were determined,and genomic analysis was applied to assess their genetic heterogeneity.Additionally,resistance genes were detected.Results:Salmonella 4,[5],12:i:-strains exhibited varying levels of resistance to the tested antibiotics,with an overall resistance rate of 98.83%,MDR rate of 87.98%,and cefotaxime resistance of 25.91%.An increasing trend was observed for resistance to key antibiotics and AMR determinants from 2020–2023.Whole-genome analysis revealed five clades with high genetic diversity(A–E),with 97.33%belonging to ST34.Clade D carried a significant proportion of ESBL genes.Moreover,we identified 15 meropenemresistant isolates primarily harboring widely distributed plasmids containing multiple resistance genes,including blaNDM-5 and blaOXA-10.Conclusion:Salmonella 4,[5],12:i:-is highly sporadic in China but remains phylogenetically linked to the prevalent MDR clone with a distinct resistance profile worldwide.The emergence of elevated resistance to third-generation cephalosporins and sharp rise in carbapenem resistance,coupled with the detection of plasmid-mediated resistance determinants,suggests the evolution of endemic MDR clones circulating within China.These findings emphasize the need for enhanced surveillance,stricter regulations on antibiotic use in agriculture,comprehensive risk factor surveys,and targeted interventions to prevent outbreaks.展开更多
During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in...During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in pathogenesis. We used in vivo induced antigen technology (IVIAT) to identify antigens which are expressed during infection with Salmonella enterica serovar Typhi. We identified 7 in vivo induced (IVI) antigens, which included BcfD (a fimbrial structural subunit), GrxC (a glutaredoxin 3), SapB (an ABC-type transport system), T3663 (an ABC-type uncharacterized transport system), T3816 (a putative rhodanese-related sulfurtransferase), T1497 (a probable TonB-dependent receptor) and T3689 (unknown function). Of the 7 identified antigens, 5 antigens had no cross-immunoreactivity in adsorbed control sera from healthy subjects. These 5 included BcfD, GrxC, SapB, T3663 and T3689. Antigens identified in this study are potential targets for drug and vaccine development and may be utilized as diagnostic agents.展开更多
Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recogni...Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.展开更多
pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were...pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were present in S.typhi.In our current study,we investigated whether plasmid pRST98 exhibits significant cytotoxicity in macrophages.pRST98 was transferred into the avirulent Salmonella enterica serovar Typhimurium(S.typhimurium)strain RIA to create the transconjugant pRST98/RIA.The standard S.typhimurium virulent strain SR-11,which carries a 100-kb virulence plasmid,was used as a positive control.The bacterial strains were incubated with a murine macrophage-like cell line(J774A.1)in vitro.Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling,and the survival of Salmonella strains in J774A.1 cells was determined.Results showed that macrophages infected with strain pRST98/RIA displayed greater levels of apoptosis than those infected with RIA and that pRST98 may increase bacterial survival in macrophages.Further studies showed that the pRST98-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pRST98 may activate caspase-9 and then caspase-3.The research data indicate that the virulence of bacteria that contain the pRST98 plasmid is enhanced;the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.展开更多
基金supported by the Earmarked fund for China Agriculture Research System of MOF and MARA(Grant No.CARS-41-G01).
文摘Background Salmonella enterica serovar Enteritidis(S.Enteritidis)is a global foodborne pathogen that poses a significant threat to human health,with poultry being the primary reservoir host.Therefore,addressing S.Enteritidis infections in poultry is crucial to protect human health and the poultry industry.In this study,we investigated the effect of co-housing Arbor Acres(AA)chickens,a commercial breed susceptible to S.Enteritidis,with Tibetan chickens,a local breed resistant to S.Enteritidis infection,on the resistance of the latter to the pathogen.Results Ninety-six 1-day-old Tibetan chickens and 961-day-old AA chickens were divided into a Tibetan chicken housed alone group(n=48),an AA chicken housed alone group(n=48),and a co-housed group(48 birds from each breed for 2 cages).All birds were provided the same diet,and the experimental period lasted 14 d.At d 7,all chickens were infected with S.Enteritidis,and samples were collected at 1-,3-,and 7-day-post-infection.We found that the body weight of AA chickens significantly increased when co-housed with Tibetan chickens at 1-and 3-day-post-infection(P<0.05).In addition,the cecal S.Enteritidis load in AA chickens was significantly reduced at 1-,3-,and 7-day-post-infection(P<0.05).Furthermore,the inflammatory response in AA chickens decreased,as evidenced by the decreased expression of proinflammatory cytokines NOS2,TNF-α,IL-8,IL-1β,and IFN-γin their cecal tonsils(P<0.05).Co-housing with Tibetan chickens significantly increased the height of villi and number of goblet cells(P<0.05),as well as the expression of claudin-1(P<0.05),a tight junction protein,in the jejunum of AA chickens.Further analysis revealed that co-housing altered the gut microbiota composition in AA chickens;specifically,the relative abundances of harmful microbes,such as Intestinimonas,Oscillibacter,Tuzzerella,Anaerotruncus,Paludicola,and Anaerofilum were reduced(P<0.05).Conclusions Our findings indicate that co-housing with Tibetan chickens enhanced the resistance of AA chickens to S.Enteritidis infection without compromising the resistance of Tibetan chickens.This study provides a novel approach for Salmonella control in practical poultry production.
基金supported financially by the National Key Research and Science Program of the Ministry of Science and Technology of the People’s Republic of China(2022YFC2303900)the Beijing Natural Science Foundation(7232242).
文摘Antimicrobial resistance(AMR)has become a critical global public health challenge in the 21st century.Since the initial isolation of a blaNDM-1-carrying and carbapenem-resistant Klebsiella pneumoniae from an Indian hospital in 2009[1],the escalating prevalence of New Delhi metallo-β-lactamase(NDM)-encoding genes(blaNDM)has transformed carbapenem resistance into a worldwide phenomenon,transcending national and regional boundaries[2].Up to 90 distinct NDM variants have been reported globally according to the NCBI GenBank Pathogens database.Plasmidmediated horizontal gene transfer(HGT),which occurs both within and across bacterial species,has significantly accelerated the global dissemination of blaNDM-related genes and the associated resistance[3].Carbapenem-resistant pathogens were responsible for 200,000 deaths globally in 2019[4].Although NDM-1 has been relatively well characterized[5],the epidemiological profiles of other NDM variants require continued surveillance and indepth investigation.The novel NDM-9 variant(GenBank accession no.KC999080)was first identified in 2013 from a clinically significant isolate of Klebsiella pneumoniae ST107 strain PPH1303 with a high level of resistance to carbapenems recovered from the urine culture of a pediatric patient in Beijing,China,who had acute lymphocytic leukemia and had undergone allogeneic stem cell transplantation[6].
基金supported by the National Key Research and Development Program of China(2022YFC3600700)the National Natural Science Foundation of China(82370778)+2 种基金the Hubei Provincial Natural Science Foundation of China(2023AFA061)the Fundamental Research Funds for the Central Universities(2042024kf1043)the Young Top-Notch Talent Cultivation Program of Hubei Province(for Prof.Zeng XT).
文摘Background:Fibrosis constitutes a significant pathophysiological mechanism in the clinical progression of benign prostatic hyperplasia(BPH)and represents a contributing factor to the ineffectiveness of prevailing pharmacological treatments.Emerging evidence suggests a close association between microbial presence and the development of fibrosis.Nonetheless,the potential involvement of microbes within prostatic tissue in the pathogenesis of BPH and prostatic fibrosis,along with the underlying mechanisms,remains unexplored.Methods:Utilizing immunohistochemistry and microbial sequencing,we analyzed the microbes of prostate tissues from BPH patients with different degrees of prostate fibrosis and found that Salmonellaenterica(S.enterica)was enriched in the high degree of prostate fibrosis.We developed prostate cell and animal models infected with the lipopolysaccharide of S.enterica(S.e-LPS)to assess its impact on prostate fibrosis.To elucidate the underlying functional mechanisms,we employed molecular biology techniques,including RNA degradation assays,N6-methyladenosine(m6A)dot blotting,RNA immunoprecipitation,and m6A immunoprecipitation.Results:Microbial diversity differed between low-and high-fibrosis groups,with S.enterica showing the highest mean abundance among the 4 species that differed significantly.S.e-LPS was detected in S.enterica-rich prostate tissue and was found to significantly promote cell proliferation,cell contractility,lipid peroxidation,and the induction of ferroptosis.Animal experiments demonstrated that S.e-LPS infection led to pronounced hyperplasia of the prostatic epithelium,with epithelial thickness increasing to 1.57 times that of the sham group,and collagen fibrosis increasing to 2.84 times that of the sham group,thereby exacerbating prostatic tissue fibrosis in rats.Invitro experiments further revealed that S.e-LPS promoted prostate cell fibrosis by inducing ferroptosis.Mechanistically,it was determined that S.e-LPS regulates ferroptosis via AlkB homolog 5(ALKBH5)-mediated m6A modification,which affects the stability of glutathione peroxidase 4(GPX4)mRNA,thereby affecting prostatic fibrosis.Conclusion:The findings of this study suggest that S.enterica promotes prostatic fibrosis through ALKBH5-m6A-GPX4-mediated ferroptosis.This research offers novel insights for the development of new therapeutic targets and personalized strategies for the prevention and treatment of BPH from the perspectives of microbes and epigenetics.
文摘Objective:To develop allenualed slrains of Salmonella enterica serorar Typhi(S.typhi) for the candidate vaccine by osmolar stress.Mothods:S.typhi SS3 and SS5 strains were isolated from asymptomatic typhoid carriers in Mamakkal,Tamil Nadu.India.Both strains were grown in LB(Luria Bertani) medium supplemented with various concentration of NaCl(0.1- 0.7M) respectively.The effecl of osmolar stress was determined at molecular level by PCR using MCR 06 and MCR07 primers corresponding to ompR with chromosomal DNA of S.typhi SS3 and SS5 strains.Attenuation by osmolar stress results in deletion mutation of the.S.typhi slrains was determined by agglutination assays,precipitation method.SDS PAGE analysis and by animal models.Results:The 799 bp amplified ompR gene product from wild type S.typhi SS3 and SS5 illustrate the presence of virulent gene.Interestingly,there was only a 282 bp amplified product from S.typhi SS3 and SS5 grown in the presence of 0.5.0.6 and 0.7 M NaCl.This illustrates the occurrence of deletion mutation in ompR gene al high concentration of NaCl.Furthermore,both the wildtype and mutant S.typhi outer membrane SDS-PAGF.profile reveals the differences in the expression of ompF.ompC and ompA proteins.In mice,wild type and mutant strains lethal dose(LD_(50)) were determined.The mice died within 72 h when both the wild type strains were injected intraperitoneally with 3 log CFU-mL^(-1).When the mice were injected with the mutants in same dosage,no clinical symptoms were observed;whereas the serum antibodv litre was elicited within two weeks indicated that the mutants have the ability to induce protective humoral immune response.These results suggest that S.typhi SS3 and SS5 may bo used as good candidate strains for the development of live attenuated vaccine against salmonellosis.Conclusions:This study demonstrates that the S.typhi strains were allenualed and could be good vaccine candidates in future.
基金financially supported by the University of Malaya Research Grant (UMRG) (RP003A-13BIO)UM Postgraduate Research Fund (PPP) (PS319/2010B)
文摘Salmonella is a member of the family Enterobacteriaceae. This genus comprises two species, namely Salmonella enterica and Salmonella bongori. Salmonella enterica is further divided into six subspecies, namely enterica, salamae, arizonae,
文摘本研究对重庆荣昌采后发病姜块进行病原菌分离鉴定,分离到一株新的生姜致病菌。通过细菌形态、生理生化、16S r DNA遗传分析鉴定为沙门氏菌(Salmonella enterica)。将沙门氏菌回接姜苗、姜块,发现姜苗叶片失绿,褶皱;姜块表面水渍并有分泌物;动态污染研究表明:沙门氏菌能在姜块中迅速繁殖,显著提高姜块超氧化物歧化酶(superoxide dismutase,SOD)、过氧化物酶(peroxidase,POD)、过氧化氢酶(catalase,CAT)的活性。该研究表明,沙门氏菌能以生姜为寄主存活。
文摘Objective:To evaluate the antibacterial activity of Ocimum sanctum(O.sanctum) leaf extract, alone,and in combination with chloramphenicol(C) and trimethoprim(Tm) against Salmonella enterica serovar Typhi(S.typhi).Methods:The antibacterial activity of ethanolic extract of tulsi, 0.sanctum,leaf(TLE:500μg) for 23 S.typhi isolates was determined following agar diffusion. The C(30μg) and Tm(5μg) activity alone and in combination with TLE(250μg) was determined by disk diffusion.The zone diameter of inhibition(ZDI) for the agents was recorded, and growth inhibitory indices(Glls) were calculated.Results:The S.typhi isolates(n=23),which were resistant to both C(ZDI 6 mm) and Tm(ZDI 6 mm),had TLE(500μg) ZDIs 16-24 mm.The ZDIs of C and Tm were increased up to 15-21 mm and 17-23 mm,respectively,when TLE(250μg) was added to the C and Tm discs.The Glls ranged 0.789-1.235 and 0.894-1.352,due to combined activity against S.typhi isolates,of C and TLE and Tm and TLE.respeclivelv.Conclusions:The data suggest that TLE,in combination with C and Tm,had synergistic activity for S.typhi isolates, and hence O.sanclum is potential in combating S.typhi drug resistance,as well promising in the development of non-antibiotic drug for S.typhi infection.
文摘Objective:To construct a novel plasmid as Salmonella enterica serovar typhimurium(S.typhimurium)sip C gene knockouts candidate.Methods:In this research,50upstream and 30downstream regions of S.typhimurium sip C gene and kanamycin gene were PCR amplified.Each of these DNA fragment was cloned into p GEM T-easy vector.The construct was confirmed by PCR and restriction digest.Results:PCR amplified 320,206 and 835 bp DNA fragments were subcloned into p ET-32 vector resulting with a plasmid called p ET-32-sip C up-kan-sip C down.Conclusions:The new plasmid(p ET-32-sip C up-kan-sip C down)is useful for genetic engineering and for future manipulation of S.typhimurium sip C gene.
文摘Objective: To identify the region conferring stability to pBSSB2(a linear plasmid, pBSSB1, containing a kanamycin cassette), which is unique to Indonesian isolates of Salmonella enterica serovar Typhi. Methods: The open reading frame(ORF) 009 was identified as a toxin coding gene in the plasmid through introduction of translational termination codons in the ORF. Results: The stability function was located in a fragment that spanned nucleotides 5 766 to 6 828 in the linear plasmid genetic map. Ectopic expression of ORF009 in pBAD18 vector indicated ORF009 codes for a toxin. This fragment could stabilize plasmid pUC18 previously destabilized through mutation of the pcnB(plasmid copy number control) gene that codes for polyA polymerase. Majority of the cells expressing ORF009 were non-viable according to phase contrast microscopy. Conclusions: This study demonstrated that a linear plasmid fragment that carries a gene encoding a toxin possibly conferred stability to the parent plasmid. It was able to stabilize a multicopy plasmid of Escherichia coli.
文摘Salmonella enterica serovar Enteritidis (SE)-induced diarrhea in humans is the typical non-typhoid diarrhea. It develops acutely or subacutely and may be fatal. This SE infectious disease suddenly became a major public health issue worldwide in the 1980s. The main causative food material of SE food poisoning is chicken eggs, and many outbreaks of food poisoning caused by chicken eggs occurred throughout the world. SE epidemics occurred in layer farms, and this was the main cause of SE-induced food poisoning in humans. The major subject of our epidemiological study described in this report is why SE-contaminated eggs became the main causative food. In this study, we focused on difference of molecular expression for farm-isolated SEs. That is because recent studies have demonstrated that O-antigen enlargement may be related to pathogenicity in mice as well as 22-kDa polypeptide-expression (SEp22). We have discovered that many SE strains isolated from chicken farms do not express SEp22, and a deficiency or decreased level of cellular antigen 0-12 in SE strains isolated from chicken farms was clarified in a report. Additionally, SEp22 was deficient in SE strains passaged through chickens, whereas SEp22 was expressed at a high level in SE strains passaged through mice. These findings suggest that SE infection and retention more effectively occur in layer farms than in other animal maintenance environments, which may be a basis of the epidemiological hypothesis to explain the high-levelproduction of SE-contaminated eggs (the presence of mice may be the basis of the retention of SE infection in layer farms, and this may also be the mechanism causing the high-level production of SE-contaminated eggs).
文摘Salmonella is a common cause of foodborne illness within the United States with the severity of the infection being a factor of both the age and overall health of the infected individual. The nematode worm Caenorhabditis elegans has proven to be a useful model to study infection dynamics of pathogenic bacteria, including Salmonella enterica, and its short lifespan makes it a powerful model system to assess the effect of organismal age on infection severity. In this study, we infected C. elegans with each of 6 serovars of S. enterica at 1, 3 or 5 days of worm age and monitored their survival. Worms infected with E. coli OP50 were used as a control. Infection with S. enterica resulted in a significant reduction in mean longevity relative to OP50 (p < 0.05);however, there was no significant effect of age on mean survival time regardless of the strain of bacteria used.
基金Supported by Zhejiang Province Health and Wellness Science and Technology Program in 2022,China,No.2022RC202.
文摘BACKGROUND Secondary hemophagocytic lymphohistiocytosis(sHLH)triggered by Salmonella enterica serovar Typhimurium is rare in pediatric patients.There is no consensus on how to treat S.typhimurium-triggered sHLH.CASE SUMMARY A 9-year-old boy with intermittent fever for 3 d presented to our hospital with positive results for S.typhimurium,human rhinovirus,and Mycoplasma pneumoniae infections.At the time of admission to our institution,the patient’s T helper 1/T helper 2 cytokine levels were 326 pg/mL for interleukin 6(IL-6),9.1 pg/mL for IL-10,and 246.7 pg/mL for interferon-gamma(IFN-γ),for which the ratio of IL-10 to IFN-γwas 0.04.In this study,the patient received meropenem,linezolid,and cefoperazone/sulbactam in combination with high-dose methylprednisolone therapy(10 mg/kg/d for 3 d)and antishock supportive treatment twice.After careful evaluation,this patient did not receive HLH chemotherapy and recovered well.CONCLUSION S.Typhimurium infection-triggered sHLH patient had a ratio of IL-10 to IFN-γ≤1.33,an IL-10 concentration≤10.0 pg/mL,and/or an IFN-γconcentration≤225 pg/mL at admission.Early antimicrobial and supportive treatment was sufficient,and the HLH-94/2004 protocol was not necessary under these conditions.
文摘Food-borne salmonellosis continues to be a major health concern worldwide. Carry-contamination of Salmonella frequently occurs in meat production. We focused on cell dynamics of swine fibroblasts after infection with Salmonella enterica serovar Enteritidis and Typhimurium, because fibroblast can be a target cell for Salmonella latent infection. It was found that both S. Enteritidis and S. Typhimurium were able to adhere and invade to swine fibroblasts. The proliferations in fibroblasts were different between each serovar. S. Enteritidis reached to the maximum at 24 hr after infection while S. Typhimurium did not. In addition, the decrease in the G<sub>0</sub>/G<sub>1</sub> phase cells and increase in G<sub>2</sub>/M phase cells on the fibroblast were observed by both Salmonella infection. Cell death including apoptosis in the cells was inhibited by the infection of Salmonella. These results suggest that nontyphoidal Salmonella can survive for the long term by modifying bacterial cell proliferation and preventing cell death of host cells.
文摘<span><i><span style="font-family:""><i></span></i></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> serovars is a leading cause of human gastroenteritis, and the incidence of salmonellosis is constantly increasing, causing millions of infections and many deaths annually. The detection of the pathogen in optimal terms is an essential factor for reducing the impact on the human body. In this work</span></span></span><span><span><span style="font-family:"">,</span></span></span><span><span><span style="font-family:""> SYBR Green I-based qPCR method of detection and quantifica<span>tion of </span></span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><i><span style="font-family:""> </span></i></span></span><span><span><span style="font-family:"">was</span></span></span><span><span><span style="font-family:""> developed and validated. For detection o</span></span></span><span><span><span style="font-family:"">f </span></span></span><span><span><span style="font-family:""><i></span></span></span><span><span><i><span style="font-family:"">Salmonella enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:""> subsp.<i> </i></span></span></span><span><span><i><span style="font-family:""><i></span></i></span></span><span><span><i><span style="font-family:"">enterica</span></i></span></span><span><span><i><span style="font-family:""></i></span></i></span></span><span><span><span style="font-family:"">, two pairs of primers were designed using publically available Primer-BLAST software. Primer efficiency was calculated <span>by establishing a standard curve. The specificity, sensitivity, accuracy, and</span> precision of PCR results were tested. Both primer pairs showed an acceptable performance, proving the developed techniques were sensitive, reliable and precise. The validated <span>qPCR technology has a good potential to replace the traditional culture method in microbial diagnosis.
基金Supported in part by grants from the Project for the National Key Research and Development Program of China(2023YFC2307101)Young Scientist of the Joint Funds of Science and Technology Research and Development Plan of Henan Province,China(235200810058)Young TopNotch Talents Foundation of Henan Agricultural University(30501278).
文摘We read the study conducted by Cui et al.published in China CDC Weekly with great interest,and would like to make comment on this matter(1).The report identified 31 Salmonella enterica serovar I 1,4,[5],12:i:-(S.I 1,4,[5],12:i:-)sequence type 8333(ST8333)genomes by the end of 2023 in the National Molecular Tracing Network for Foodborne Disease Surveillance database.The overall percentage of isolates of S.I 1,4,[5],12:i:-ST8333 remained low in their active monitoring between 2017 and 2023,and observed ST8333 in 2017.
基金supported by the National Natural Science Foundation of China(Grant 7252170).
文摘Salmonella,a gram-negative bacterium from the Enterobacteriaceae family,is widely distributed in nature.To date,over 2600 serotypes have been identified.Salmonella enterica serovar Kentucky(S.Kentucky)is considered to be a“super-resistant”strain of Salmonella in Europe and the USA and is a rare serotype in China.Clinical isolates are typically obtained from patients’fecal samples,with no previous reports of isolation from the eyes.Here,we report a case of isolation of S.Kentucky from the purulent aspirate of an orbital abscess during routine clinical practice.The infection was successfully managed by surgical excision of the primary lesion in combination with targeted antibiotic treatment.This case thus emphasizes the need for clinicians to select antibiotics based on antimicrobial susceptibility reports.
文摘Introduction:Salmonella 4,[5],12:i:-,a globally emerging pathogen with multidrug resistance(MDR),is spreading in China.Nationwide data on the antimicrobial resistance(AMR)and genomic characteristics of Salmonella 4,[5],12:i:-from human sources in China are scarce.This study aimed to characterize the prevalence,genetic diversity,and AMR profiles of Salmonella 4,[5],12:i:-in China.Methods:All information,including geographical data,antimicrobial susceptibility test results,and whole-genome sequences,was extracted from the Chinese Pathogen Identification Network database from 2017 to 2023.Antimicrobial resistance phenotypes of 2,736 human-derived isolates were determined,and genomic analysis was applied to assess their genetic heterogeneity.Additionally,resistance genes were detected.Results:Salmonella 4,[5],12:i:-strains exhibited varying levels of resistance to the tested antibiotics,with an overall resistance rate of 98.83%,MDR rate of 87.98%,and cefotaxime resistance of 25.91%.An increasing trend was observed for resistance to key antibiotics and AMR determinants from 2020–2023.Whole-genome analysis revealed five clades with high genetic diversity(A–E),with 97.33%belonging to ST34.Clade D carried a significant proportion of ESBL genes.Moreover,we identified 15 meropenemresistant isolates primarily harboring widely distributed plasmids containing multiple resistance genes,including blaNDM-5 and blaOXA-10.Conclusion:Salmonella 4,[5],12:i:-is highly sporadic in China but remains phylogenetically linked to the prevalent MDR clone with a distinct resistance profile worldwide.The emergence of elevated resistance to third-generation cephalosporins and sharp rise in carbapenem resistance,coupled with the detection of plasmid-mediated resistance determinants,suggests the evolution of endemic MDR clones circulating within China.These findings emphasize the need for enhanced surveillance,stricter regulations on antibiotic use in agriculture,comprehensive risk factor surveys,and targeted interventions to prevent outbreaks.
基金Supported by the National Natural Science Foundation of China (Grant No. 30500435)
文摘During infectious disease episodes, pathogens express distinct subsets of virulence factors which allow them to adapt to different environments. Hence, genes that are expressed or upregulated in vivo are implicated in pathogenesis. We used in vivo induced antigen technology (IVIAT) to identify antigens which are expressed during infection with Salmonella enterica serovar Typhi. We identified 7 in vivo induced (IVI) antigens, which included BcfD (a fimbrial structural subunit), GrxC (a glutaredoxin 3), SapB (an ABC-type transport system), T3663 (an ABC-type uncharacterized transport system), T3816 (a putative rhodanese-related sulfurtransferase), T1497 (a probable TonB-dependent receptor) and T3689 (unknown function). Of the 7 identified antigens, 5 antigens had no cross-immunoreactivity in adsorbed control sera from healthy subjects. These 5 included BcfD, GrxC, SapB, T3663 and T3689. Antigens identified in this study are potential targets for drug and vaccine development and may be utilized as diagnostic agents.
文摘Infections with Salmonella enterica belong to the most prominent causes of food poisoning and infected fruits and vegetables represent important vectors for salmonellosis. Recent evidence indicates that plants recognize S. enterica and raise defense responses. Nonetheless, the molecular mechanisms controlling the interaction of S. enterica with plants are still largely unclear. Here, we show that flagellin from S. enterica represents a prominent pathogenassociated molecular pattern （PAMP） in Arabidopsis thaliana, which induces PAMP-triggered immunity （PTI） via the recognition of the fig22 domain by the receptor kinase FLS2. The Arabidopsis fls2 mutant shows reduced though not abolished PTI activation, indicating that plants rely also on recognition of other S. enterica PAMPs. Interestingly, the S. enterica type III secretion system （T3SS） mutant prgH- induced stronger defense gene expression than wild-type bacteria in Arabidopsis, suggesting that T3SS effectors are involved in defense suppression. Furthermore, we observe that S. enterica strains show variation in the fig22 epitope, which results in proteins with reduced PTI-inducing activity. Altogether, these results show that S. enterica activates PTI in Arabidopsis and suggest that, in order to accomplish plant colonization, S. enterica evolved strategies to avoid or suppress PTI.
基金supported by the Natural Science Foundation of China(No.30972768)the Special and General Postdoctoral Science Foundation of China(No.200902529 and No.20080430178)+1 种基金the Natural Science Foundation of Jiangsu High Education Institute of China(No.08KJB310009)the Social Development Science Foundation of Suzhou City of China(No.SS08025).
文摘pRST98 is a chimeric plasmid isolated from Salmonella enterica serovar Typhi(S.typhi)that mediates the functions of drug resistance and virulence.Previously,we reported that Salmonella plasmid virulence(spv)genes were present in S.typhi.In our current study,we investigated whether plasmid pRST98 exhibits significant cytotoxicity in macrophages.pRST98 was transferred into the avirulent Salmonella enterica serovar Typhimurium(S.typhimurium)strain RIA to create the transconjugant pRST98/RIA.The standard S.typhimurium virulent strain SR-11,which carries a 100-kb virulence plasmid,was used as a positive control.The bacterial strains were incubated with a murine macrophage-like cell line(J774A.1)in vitro.Apoptosis of J774A.1 cells was examined by electron microscopy and flow cytometry after annexin-V/propidium iodide labeling,and the survival of Salmonella strains in J774A.1 cells was determined.Results showed that macrophages infected with strain pRST98/RIA displayed greater levels of apoptosis than those infected with RIA and that pRST98 may increase bacterial survival in macrophages.Further studies showed that the pRST98-induced death of macrophages was associated with the loss of mitochondrial membrane potential and that pRST98 may activate caspase-9 and then caspase-3.The research data indicate that the virulence of bacteria that contain the pRST98 plasmid is enhanced;the presence of this plasmid increases the survival of the bacterial pathogen and acts through the mitochondrial pathway to mediate macrophage apoptosis.
