Due to the use of vaccines,infections caused by Corynebacterium diphtheriae are now rare.Here we describe a case of bacteremia complicated with pneumonia caused by C.diphtheriae in a 69-year-old male patient.The patie...Due to the use of vaccines,infections caused by Corynebacterium diphtheriae are now rare.Here we describe a case of bacteremia complicated with pneumonia caused by C.diphtheriae in a 69-year-old male patient.The patient presented at the emergency department with a 2 days history of fever of unknown origin.Subsequent examinations revealed pneumonia and bacteremia.Non-toxigenic C.diphtheriae strains were isolated from blood and sputum.The patient had antimicrobial therapy with good improvement.We highlight the important role of C.diphtheriae in causing bacteremia and pneumonia,and its accurate and timely diagnosis is needed to avoid poor visual outcomes.展开更多
Diphtheria is a fulminant bacterial disease caused by toxigenic strains of Corynebacterium diphtheriae whose local and systemic manifestations are due to the action of the diphtheria toxin (DT). The vaccine which is u...Diphtheria is a fulminant bacterial disease caused by toxigenic strains of Corynebacterium diphtheriae whose local and systemic manifestations are due to the action of the diphtheria toxin (DT). The vaccine which is used to prevent diphtheria worldwide is a toxoid obtained by detoxifying DT. Although associated with high efficacy in the prevention of disease, the current anti-diphtheria vaccine, one of the components of DTP (diphtheria, tetanus and pertussis triple vaccine), may present post vaccination effects such as toxicity and reactogenicity resulting from the presence of contaminants in the vaccine that originated during the process of production and/or detoxification. Therefore, strategies to develop a less toxic and at the same time economically viable vaccine alternatives are needed to improve existing vaccines in use worldwide. In this study, the Moreau substrain of BCG which is used in Brazil as a live vaccine against human tuberculosis was genetically modified to carry and express the gene encoding for the diphtheria toxin fragment B (DTB). As such, the DNA sequence encoding the dtb gene was cloned into the pUS977 shuttle vector for cytoplasmic expression and successfully introduced into BCG cells by electroporation. Mice immunized with recombinant BCG expressing DTB showed seroconversion with the detection of specific antibodies against DTB. Also, rBCGs stably expressing DTB persisted up to 60 days in the absence of selective pressure in mice and cell viability did not change significantly during the period tested. Finally, immune sera from BALB/c mice vaccinated with rBCGpUS977dtbPW8 were preliminarily tested for their capacity of neutralizing the diphtheria toxin in the Vero Cells assay.展开更多
AIM To establish a tissue-specific gene therapy for colorectal carcinoma using bacterial ADP-ribosylating toxin genes.METHODS Pseudomonas exotoxin A domain Ⅱ+Ⅲ (PEA) was cloned from genomic DNA of Pseudomonas aerugi...AIM To establish a tissue-specific gene therapy for colorectal carcinoma using bacterial ADP-ribosylating toxin genes.METHODS Pseudomonas exotoxin A domain Ⅱ+Ⅲ (PEA) was cloned from genomic DNA of Pseudomonas aeruginosa. PEA and diphtheria toxin A chain gene (DTA) were modified to express eukaryotically. After sequencing, the toxin genes under the control of human carcinoembryonic antigen (CEA) promoter were cloned into retroviral vectors to construct CEAPEA and CEADTA respectively. In vitro cotransfection of the constructs with luciferase vectors and in vivo gene transfer in nude mice were subsequently carried out.RESULTS Both CEAPEA and CEADTA specifically inhibited the reporter gene expression in the CEA positive human colorectal carcinoma (CRC) cells in vitro. Direct injection of CEAPEA and CEADTA constructs into the established human tumors in BALB/c nude mice led to significant and selective reductions in CRC tumor size as compared with that in control groups.CONCLUSION The toxin genes, working as therapeutic genes, are suitable for the tissue-specific gene therapy for colorectal carcinoma.展开更多
AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphthe...AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphtheria toxin receptor(DTR) transgenic mice and severe combined immune deficient(SCID)-beige mice,to create Alb-cre/DTR/SCID-beige(ADSB) mice,which coincidentally harbor Alb-cre and DTR transgenes and are immunodeficient. As the Cre expression is driven by the liver-specific promoter Alb(encoding ALB),the DTR stop signal flanked by two lox P sites can be deleted in the ADSB mice,resulting in DTR expression in the liver. ADSB mice aged 8-10 wk were injected intraperitoneally(i.p.) with diphtheria toxin(DT) and liver damage was assessed by serum alanine aminotransferase(ALT) level. Two days later,mouse livers were sampled for histological analysis,and human hepatocytes were transplanted into the livers on the same day. A human ALB enzyme-linked immunosorbent assay was performed 7,14,21 and 28 d after transplantation. Human CD68 immunohistochemistry was performed 30 and 90 d after transplantation.RESULTS We crossed Alb-cre with DTR and SCID-beige mice to obtain ADSB mice. These mice were found to have liver damage 4 d after i.p. injection of 2.5 ng/g bodyweight DT. Bodyweight began to decrease on day 2,increased on day 7,and was lowest on day 4(range,10.5%-13.4%). Serum ALT activity began to increase on day 2 and reached a peak value of 289.7 ± 16.2 IU/m L on day 4,then returned to background values on day 7. After transplantation of human liver cells,peripheral blood human ALB level was 1580 ± 454.8 ng/m L(range,750.2-3064.9 ng/m L) after 28 d and Kupffer cells were present in the liver at 30 d in ADSB mice.CONCLUSION Human hepatocytes were successfully repopulated in the livers of ADSB mice. The inducible mouse model of humanized liver in ADSB mice may have functional applications,such as hepatocyte transplantation,hepatic regeneration and drug metabolism.展开更多
Aim:Pertussis is a respiratory tract infection,the vaccine for which was introduced in the Expanded Programme on Immunization(EPI)in Guizhou Province of China(hereafter referred as Guizhou)in the 1980s.This vaccine ra...Aim:Pertussis is a respiratory tract infection,the vaccine for which was introduced in the Expanded Programme on Immunization(EPI)in Guizhou Province of China(hereafter referred as Guizhou)in the 1980s.This vaccine rapidly decreased incidence rates of pertussis in the province,however,despite the wide high coverage of the diphtheria,tetanus and acellular pertussis(DTaP)combined vaccine,there has been a resurgence of pertussis since 2014.Even with this recent increase in disease transmission,risk factors for pertussis infection have not been evaluated in Guizhou.We aimed to provide information on pertussis risk factors and insight on designing targeted pertussis control policies and measures through this study.Methods:A 1:2 matched retrospective case-control study was conducted between 2016 and 2017,involving infants and children younger than 6 years old and parents of the participants.The enrolled cases included clinical and laboratory confirmed pertussis cases according to the WHO-recommended pertussis definition.Controls were selected from children in the same neighborhood who were not diagnosed with pertussis prior to our investigation and did not exhibit any clinical manifestations of pertussis.Results:The household size[Matched odds ratio(OR_(m)=1.4,95%confidence interval(Cl):1.1-1.7]and household members with antecedent cough(OR_(m)=3.6,95%CI:1.8-7.2)were significantly associated with their child’s pertussis onset.The parents’occupations were significantly associated with their child’s pertussis onset(ORm=9.4,95%CI:1.6-54.8,for mother side;ORm=4.5,95%CI:1.2-16.5,for father side),when they worked in the business and/or service industry.Having family members with a history of cough was an independent risk factor for pertussis[Adjusted odds ratio(AOR)=43.6,95%CI:2.7-694.0].Besides,the parents’demographic characteristics and DTaP doses were not found to be independent factors.Conclusion:Household exposure is an important risk factor for pertussis infection in infants and young children and should therefore be considered as a major factor during formulation of pertussis control policies and measures.展开更多
Three diphtheria toxin (DT) mutants CRM-197, DT-del (148) and DT-El48S-K516A-F530A were cloned in B- Subtilis plasmid PSM604 under the subtilisin signal sequence. The expression was effective in both SMS300 and SMS118...Three diphtheria toxin (DT) mutants CRM-197, DT-del (148) and DT-El48S-K516A-F530A were cloned in B- Subtilis plasmid PSM604 under the subtilisin signal sequence. The expression was effective in both SMS300 and SMS118, but higher yield of 7. 1 mg/L was observed in SMS300 compared with 2. 1 mg/L in SMS118. Western blot showed that the recombinant protein could be effectively secreted into the culture medium as a 58 ku peptide, and could be de-graded into two peptides of 37ku and 21ku.展开更多
Objective： This study aimed to express a fusion protein of diphtheria toxin and human B cell-activating factor （DT388sBAFF） in Escherichia coli （E. coli） and investigate its activity in human B-lineage acute lymp...Objective： This study aimed to express a fusion protein of diphtheria toxin and human B cell-activating factor （DT388sBAFF） in Escherichia coli （E. coli） and investigate its activity in human B-lineage acute lymphoblastic leukemia 1 cells （BALL-1）. Methods： A fragment of DT388sBAFF fusion gene was separated from plasmid pUC57-DT388sBAFF digested with Nde I and Xho I, and inserted into the expression vector pcold II digested with the same enzymes. Recombinants were screened by the colony polymerase chain reaction （PCR） and restriction map. The recombinant expression vector was transformed into BL21 and its expression was induced by isopropyl β-D-1-thiogalactopyranoside （IPTG）. The recombinant protein was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and Western blot, and then purified by Ni2＋-NTA affinity chromatography. The expression level of B cell-activating factor receptor （BAFF-R） on BALL-1 cells was assessed by real-time PCR. The receptor binding capacity of recombinant protein was determined by cell fluorescent assay. The specific cytotoxicity of recombinant protein on BALL-1 cells was detected by 3-（4,5-dimethylthiazolyl-2）-2,5-diphenyltetrazolium bromide （MTT） assay. Results： The expression level of recombinant protein was 50% of total bacterial proteins in E. coli, and the recombinant protein could bind to BAFF-R-positive BALL-1 cells and thereby produce a cytotoxic effect on the cells. Conclusion： The fusion protein expression vector DT388sBAFF was successfully constructed and the recombinant protein with selective cytotoxicity against BALL-1 cells was obtained, providing foundation for further study of the therapy of human B-lineage acute lymphoblastic leukemia.展开更多
Objective: To study the effects of recombinant expression vector containing human breast cancer DF3 promotor and diphtheria toxin A fragment on human breast cancer cells. Methods: Constructing recombinant expression v...Objective: To study the effects of recombinant expression vector containing human breast cancer DF3 promotor and diphtheria toxin A fragment on human breast cancer cells. Methods: Constructing recombinant expression vector PGL3-DF3-DTA and transfecting it into human breast cancer cells of DF3 positive and negative. By means of RT-PCR to measure the expression of DTA in human breast cancer cells. MTT color-imetry was used to examine the effect of PGL3-DF3-DTA on growth of human breast cancer cells. By experiment on nude mice to observe the killing effect of PGL3-DF3-DTA on human breast cancer cells. Results: Recombinant expression vector PGL3-DF3-DTA was highly expressed in human breast cancer cell line of DF3 positive, and it could kill the human breast cancer cells not only in vitro but also in vivo. Conclusion: Recombinant expression vector PGL3-DF3-DTA could produce specific killing effect on human breast cancer cell line of DF3 positive.展开更多
Despite effective vaccines, diphtheria (D) resurged recently in the former socialistic block, and tetanus (T) still occurs in less privileged countries. We studied the antibody persistence for D and T in Indian pre-sc...Despite effective vaccines, diphtheria (D) resurged recently in the former socialistic block, and tetanus (T) still occurs in less privileged countries. We studied the antibody persistence for D and T in Indian pre-school children who had received four doses of DTP vaccine and subsequently, the response to a booster dose. Anti-D and anti-T IgG antibodies prior to and one month after a DT vaccine were measured by ELISA in 223 healthy children of 4-6 years who had previously received four doses of the triple vaccine. Adverse reactions were monitored for one month. While 30% and 14% of subjects were susceptible to D and T, respectively, 98% and 100% of them attained seroprotection post-vaccination. Both responses were significant. Local, but not systemic reactions except fever were rather common. A high proportion of the Indian pre-school population is susceptible to D and T, despite of receiving four doses. The current policy of giving the fifth dose at this age is appropriate.展开更多
Background: Diphtheria is still endemic in India due to inadequate immunization. The incidence of myocarditis is higher in these patients. Objectives: The objective of this study was to study clinical profile, clinica...Background: Diphtheria is still endemic in India due to inadequate immunization. The incidence of myocarditis is higher in these patients. Objectives: The objective of this study was to study clinical profile, clinical outcomes as well as immunization status of the patients diagnosed with diphtheria myocarditis in Indian scenario. Methodology: This prospective observational study was carried out in one of the tertiary care hospital of south India from August 2011 to December 2012. A total of 33 cases with clinically confirmed diagnosis of diphtheria myocarditis were enrolled depending upon the inclusion and exclusion criteria of the study. Electrocardiography and 2-dimensional echocardiography was done at the time of admission and repeated when required. Results: The most common age group affected is 5 - 10 years, with no sex difference in occurrence. Only 1 patient, out of 33 patients, was adequately immunized. Asymptomatic myocardial involvement (with only changes in electrocardiogram) was seen in 21 patients whereas 12 patients were symptomatic. The average duration of resolution of electrocardiographic changes was 4 - 6 weeks. It should be noted that out of 28 patients who developed conduction abnormalities, 24 patients died. Temporary pacemaker support was given for 8 patients, of whom only one patient recovered. The patient was followed till hospital discharge. Conclusion: The mortality associated with diphtheria myocarditis is higher in Indian population. As diphtheria can be prevented by adequate vaccination, efforts should be maximized for 90% coverage with three doses of diphtheria toxoid in children below one year of age and immunity towards it should be maintained by booster doses.展开更多
The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DT...The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DTP vaccines available today, in particular to third world-countries. The stability of expression of heterologous antigens in BCG, however, is a major challenge to the use of live recombinant bacteria in vaccine development and appears to be dependent to a certain extent, on a genetic compatibility between the expression cassette within the plasmid construct and the mycobacterium host. In the quest for the best recombinant BCG transformant to express the dtb gene of C. diphtheriae we generated two new rBCG strains by transforming the Moreau substrain of BCG with the mycobacterial expression vectors pUS973 and pUS977, each one carrying a different promoter to drive the expression of the target antigen. After transformation recombinant BCG clones were selected on Middlebrook 7H10 kanamycin Agar plates, expanded in Middlebrook 7H9 kanamycin Broth and analyzed by agarose gel electrophoresis and immunoblotting. rBCGs transformed with the construct carrying the weak PAN promoter from M. paratuberculosis stably expressed the dtb gene. Conversely, rBCGs transformed with the construct carrying the strong mycobacterium hsp60 promoter were unstable and consequently unfit for the expression of the C. diphtheriae gene.展开更多
Background Diphtheria,caused by Corynebacterium diphtheriae,remains a serious public health threat in areas with low vaccination coverage,despite global declines due to widespread immunization and improved clinical ma...Background Diphtheria,caused by Corynebacterium diphtheriae,remains a serious public health threat in areas with low vaccination coverage,despite global declines due to widespread immunization and improved clinical management.A major outbreak in Nigeria from 2022 to 2023 underscored the persistent risk in regions with inadequate vaccination.This study aims to assess the transmission dynamics of diphtheria in Kano State,the epicenter of the outbreak,by estimating key epidemiological parameters,including the generation time(GT),approximated in our study by serial interval,and effective reproduction number(R).Methods We analyzed diphtheria case-based data from Kano State,Nigeria,collected between August 18,2022,and November 29,2023.Generation time was approximated using serial intervals in confirmed cases within the same geographical areas.The effective reproduction number(R)was calculated using four methods:Maximum Likelihood Estimation(MLE),Exponential Growth(EG),Sequential Bayesian(SB),and Time-Dependent(TD),focusing on the period of maximum exponential growth.A sensitivity analysis was conducted to quantify the impact of uncertainties in the GT derived from our data on the estimation of R.Results Over the 469-day outbreak period,13,899 diphtheria cases were reported,with complete data available for 9406 cases.The estimated mean generation time was 2.8 days(SD=3.48 days),with 97%of cases having a GT of less than 21 days.The Restimates varied across methods,with the TD method producing the highest reproduction number of 2.21 during the peak growth period.Sensitivity analysis showed that Restimates increased with longer generation times.The models,except for the SB method,demonstrated a generally strong fit with the outbreak exponential growth period.Conclusion The ongoing diphtheria outbreak in Nigeria highlights the critical threat posed by declining vaccination coverage.This study provides valuable insights into the transmission dynamics of diphtheria during a prolonged and widespread outbreak,enhancing our understanding of disease spread in this context.While certain limitations may influence the interpretation of our estimates,the findings offer valuable information for future diphtheria outbreak preparedness and response in the African context.展开更多
OBJECTIVE: To test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin Kappa light chain (IgKappa) promoter and enhancer have selective cytocidal effects on IgKappa producing ce...OBJECTIVE: To test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin Kappa light chain (IgKappa) promoter and enhancer have selective cytocidal effects on IgKappa producing cells. METHODS: The diphtheria toxin A gene or beta galactosidase (beta-gal) gene were linked to a murine IgKappa promoter and enhancer to construct pcDNA3IgKappaDTA or pcDNA3IgKappaLacZ plasmids. These plasmids were transfected into IgKappa producing or non-producing cells by the liposome coated DNA method. Expression of beta-gal activity and effects on cell growth of transfected cells were assessed. RESULTS: The beta-gal gene, under the control of cytomegalovirus (CMV) promoter, can express in all cell lines. Expression of beta-gal under the control of the IgKappa promoter was detected only in the IgKappa producing cell line, CA46. Expression of beta-gal was greatly suppressed when cotransfected with pcDNA3IgKappaDTA in CA46 cells.Cell growth of CA46 cells transfected with pcDNA3IgKappaDTA plasmid was significantly inhibited compared with CA46 cells transfected with pcDNA3IgKappaLacZ. CONCLUSION: Selective killing of IgKappa producing cells can be attained by introducing the diphtheria toxin A gene under the control of IgKappa promoter and enhancer.展开更多
A light-switchable transgene system called LightOn gene expression system could regulate gene expression with a high on/off ratio under blue light,and have great potential for spatiotemporally controllable gene expres...A light-switchable transgene system called LightOn gene expression system could regulate gene expression with a high on/off ratio under blue light,and have great potential for spatiotemporally controllable gene expression.We developed a nanoparticle drug delivery system(NDDS)to achieve tumor microenvironment-responsive and targeted delivery of diphtheria toxin A(DTA)fragment-encoded plasmids to tumor sites.The expression of DTA was induced by exposure to blue light.Nanoparticles composed of polyethylenimine and vitamin E succinate linked by a disulfide bond,and PEGylated hyaluronic acid modified with RGD peptide,accumulated in tumor tissues and were actively internalized into 4 T1 cells via dual targeting to CD44 andαvβ3 receptors.The LightOn gene expression system was able to control target protein expression through regulation of the intensity or duration of blue light exposure.In vitro studies showed that lisht-induced DTA expression reduced 4 T1 cell viability and induced apoptosis.Furthermore,the LightOn gene expression system enabled spatiotemporal control of the expression of DTA in a mouse 4 T1 tumor xenogratt model,which resulted in excellent antitumor effects,reduced tumor angiogenesis,and no systemic toxicity.The combination of the LightOn gene expression system and NDDS may be an effective strategy for treatment of breast cancer.展开更多
2013年10月,美国免疫实施咨询委员会（Advisory Committee on Immunization Practices,ACIP）推荐2-23月龄处于感染脑膜炎球菌疾病高风险的儿童接种A、C、Y和W135群脑膜炎球菌多糖-白喉类毒素变异体结合疫苗[Meningococcal Polysacchari...2013年10月,美国免疫实施咨询委员会（Advisory Committee on Immunization Practices,ACIP）推荐2-23月龄处于感染脑膜炎球菌疾病高风险的儿童接种A、C、Y和W135群脑膜炎球菌多糖-白喉类毒素变异体结合疫苗[Meningococcal Polysaccharide Groups A,C,Y and W135 Conjugate Vaccine-Diphtheria Toxin（DT）Mutant Cross ReactingMaterial，MPCV4．CRM（商品名：Menveo，诺华疫苗公司）]。展开更多
Background Certain infectious diseases are caused by specific bacterial pathogens,including syphilis,gonorrhea,typhoid and paratyphoid fever,diphtheria,pertussis,tetanus,leprosy,and tuberculosis.These diseases signifi...Background Certain infectious diseases are caused by specific bacterial pathogens,including syphilis,gonorrhea,typhoid and paratyphoid fever,diphtheria,pertussis,tetanus,leprosy,and tuberculosis.These diseases significantly impact global health,contributing heavily to the disease burden.The study aims to thoroughly evaluate the global burden of syphilis,gonorrhea,typhoid and paratyphoid fever,diphtheria,pertussis,tetanus,and leprosy.Methods Leveraging the Global Burden of Disease(GBD)study 2021,age-specific and Socio-demographic Index(SDI)-specific incidence,disability-adjusted life-years(DALYs),and death for eight specific bacterial infections across 204 countries and territories from 1990 to 2021 were analyzed.Percentage changes in age-standardized incidence rate(ASIR),DALY rate,and mortality rate(ASMR)were also examined,with a focus on disease distribution across different regions,age groups,genders,and SDI.Results By 2021,among the eight diseases,gonococcal infection had the highest global ASIR[1096.58 per 100,000 population,95%uncertainty interval(UI):838.70,1385.47 per 100,000 population],and syphilis had the highest global age-standardized DALY rate(107.13 per 100,000 population,95%UI:41.77,212.12 per 100,000 population).Except for syphilis and gonococcal infection,the age-standardized DALY rate of the remaining diseases decreased by at least 55%compared to 1990,with tetanus showing the largest decrease by at least 90%.Globally,significant declines in the ASIR,age-standardized DALY rate,and ASMR for these eight bacterial infections have been observed in association with increases in the SDI.Regions with lower SDI,such as sub-Saharan Africa,experienced a relatively higher burden of these eight bacterial infections.Conclusions Although there has been an overall decline in these eight diseases,they continue to pose significant public health challenges,particularly in low SDI regions.To further reduce this burden in these areas,targeted intervention strategies are essential,including multi-sectoral collaboration,policy support,improved WASH management,and enhanced research efforts.展开更多
A new approach of polarographlc immunoassay based on the catalytic amplification of the labeled metal ions and the polarographlc detection of the catalytic product was developed.In this approach,the copper ions used a...A new approach of polarographlc immunoassay based on the catalytic amplification of the labeled metal ions and the polarographlc detection of the catalytic product was developed.In this approach,the copper ions used as the catalyst for substrate conversion instead of natural enzyme were labeled to model antigen diphtheria toxoid (DT) through the bifunctional chelating reagent diethylenetriamine pentaacetic acid (DTPA).After heterogeneous competitive imrnunoreaction,the oxidation of substrate o-phenylenediatnine (OPD) was catalyzed by the labeled copper ions to generate an electroactive product 2,3-diammophenazine (DAP); subsequently,the product DAP was detected with linear-sweep polarography The proposed assay can determine the concentration in the range of 10-1 000 ng/mL of DT,two orders of magnitude more sensitive than those based on the direct detection of the metal ion labels The proposed immunoassay can be applied to detecting various proteins of interest.展开更多
The COVID-19 pandemic caused significant disruptions in the healthcare system,affecting vaccinations and the management of diphtheria cases.As a consequence of these disruptions,numerous countries have experienced a r...The COVID-19 pandemic caused significant disruptions in the healthcare system,affecting vaccinations and the management of diphtheria cases.As a consequence of these disruptions,numerous countries have experienced a resurgence or an increase in diphtheria cases.West Java province in Indonesia is identified as one of the high-risk areas for diphtheria,experiencing an upward trend in cases from 2021 to 2023.To analyze the situation,we developed an SIR model,which integrated DPT and booster vaccinations to determine the basic reproduction number,an essential parameter for infectious diseases.Through spatial analysis of geo-referenced data,we identified hotspots and explained diffusion in diphtheria case clusters.The calculation of R0 resulted in an R0=1.17,indicating the potential for a diphtheria outbreak in West Java.To control the increasing cases,one possible approach is to raise the booster vaccination coverage from the current 64.84%to 75.15%,as suggested by simulation results.Furthermore,the spatial analysis revealed that hot spot clusters were present in the western,central,and southern regions,posing a high risk not only in densely populated areas but also in rural regions.The diffusion pattern of diphtheria clusters displayed an expansion-contagious pattern.Understanding the rising trend of diphtheria cases and their geographic distribution can offer crucial insights for government and health authorities to manage the number of diphtheria cases and make informed decisions regarding the best prevention and intervention strategies.展开更多
基金financially supported by the National Key Research and Development Program of China[grant number 2021YFC2302002]project supported by Hainan Province Clinical Medical Center.
文摘Due to the use of vaccines,infections caused by Corynebacterium diphtheriae are now rare.Here we describe a case of bacteremia complicated with pneumonia caused by C.diphtheriae in a 69-year-old male patient.The patient presented at the emergency department with a 2 days history of fever of unknown origin.Subsequent examinations revealed pneumonia and bacteremia.Non-toxigenic C.diphtheriae strains were isolated from blood and sputum.The patient had antimicrobial therapy with good improvement.We highlight the important role of C.diphtheriae in causing bacteremia and pneumonia,and its accurate and timely diagnosis is needed to avoid poor visual outcomes.
基金The authors gratefully acknowledge supported by Bio-Manguinhos/FIOCRUZ,PAPESII/FIOCRUZ,FAPERJ,CNPq,CAPES,Programa de Nucleo de Excelencia(PRONEX/MCT/CNPq)We thank Fundacao Ataulfo de Paiva for the strain of BCG.
文摘Diphtheria is a fulminant bacterial disease caused by toxigenic strains of Corynebacterium diphtheriae whose local and systemic manifestations are due to the action of the diphtheria toxin (DT). The vaccine which is used to prevent diphtheria worldwide is a toxoid obtained by detoxifying DT. Although associated with high efficacy in the prevention of disease, the current anti-diphtheria vaccine, one of the components of DTP (diphtheria, tetanus and pertussis triple vaccine), may present post vaccination effects such as toxicity and reactogenicity resulting from the presence of contaminants in the vaccine that originated during the process of production and/or detoxification. Therefore, strategies to develop a less toxic and at the same time economically viable vaccine alternatives are needed to improve existing vaccines in use worldwide. In this study, the Moreau substrain of BCG which is used in Brazil as a live vaccine against human tuberculosis was genetically modified to carry and express the gene encoding for the diphtheria toxin fragment B (DTB). As such, the DNA sequence encoding the dtb gene was cloned into the pUS977 shuttle vector for cytoplasmic expression and successfully introduced into BCG cells by electroporation. Mice immunized with recombinant BCG expressing DTB showed seroconversion with the detection of specific antibodies against DTB. Also, rBCGs stably expressing DTB persisted up to 60 days in the absence of selective pressure in mice and cell viability did not change significantly during the period tested. Finally, immune sera from BALB/c mice vaccinated with rBCGpUS977dtbPW8 were preliminarily tested for their capacity of neutralizing the diphtheria toxin in the Vero Cells assay.
文摘AIM To establish a tissue-specific gene therapy for colorectal carcinoma using bacterial ADP-ribosylating toxin genes.METHODS Pseudomonas exotoxin A domain Ⅱ+Ⅲ (PEA) was cloned from genomic DNA of Pseudomonas aeruginosa. PEA and diphtheria toxin A chain gene (DTA) were modified to express eukaryotically. After sequencing, the toxin genes under the control of human carcinoembryonic antigen (CEA) promoter were cloned into retroviral vectors to construct CEAPEA and CEADTA respectively. In vitro cotransfection of the constructs with luciferase vectors and in vivo gene transfer in nude mice were subsequently carried out.RESULTS Both CEAPEA and CEADTA specifically inhibited the reporter gene expression in the CEA positive human colorectal carcinoma (CRC) cells in vitro. Direct injection of CEAPEA and CEADTA constructs into the established human tumors in BALB/c nude mice led to significant and selective reductions in CRC tumor size as compared with that in control groups.CONCLUSION The toxin genes, working as therapeutic genes, are suitable for the tissue-specific gene therapy for colorectal carcinoma.
基金Supported by Shanghai Science and Technology Development Foundation Project,No.12140900300Shanghai Municipal Commission of Health and Family Planning Project,No.20144Y0073+1 种基金Shanghai Public Health Clinical Center Project,No.2014M08National Science and Technology Major Project,No.2017ZX10304402-001-012
文摘AIM To establish an inducible liver injury mouse model and transplant human hepatocytes to obtain liverhumanized mice.METHODS We crossed three mouse strains,including albumin(Alb)-cre transgenic mice,inducible diphtheria toxin receptor(DTR) transgenic mice and severe combined immune deficient(SCID)-beige mice,to create Alb-cre/DTR/SCID-beige(ADSB) mice,which coincidentally harbor Alb-cre and DTR transgenes and are immunodeficient. As the Cre expression is driven by the liver-specific promoter Alb(encoding ALB),the DTR stop signal flanked by two lox P sites can be deleted in the ADSB mice,resulting in DTR expression in the liver. ADSB mice aged 8-10 wk were injected intraperitoneally(i.p.) with diphtheria toxin(DT) and liver damage was assessed by serum alanine aminotransferase(ALT) level. Two days later,mouse livers were sampled for histological analysis,and human hepatocytes were transplanted into the livers on the same day. A human ALB enzyme-linked immunosorbent assay was performed 7,14,21 and 28 d after transplantation. Human CD68 immunohistochemistry was performed 30 and 90 d after transplantation.RESULTS We crossed Alb-cre with DTR and SCID-beige mice to obtain ADSB mice. These mice were found to have liver damage 4 d after i.p. injection of 2.5 ng/g bodyweight DT. Bodyweight began to decrease on day 2,increased on day 7,and was lowest on day 4(range,10.5%-13.4%). Serum ALT activity began to increase on day 2 and reached a peak value of 289.7 ± 16.2 IU/m L on day 4,then returned to background values on day 7. After transplantation of human liver cells,peripheral blood human ALB level was 1580 ± 454.8 ng/m L(range,750.2-3064.9 ng/m L) after 28 d and Kupffer cells were present in the liver at 30 d in ADSB mice.CONCLUSION Human hepatocytes were successfully repopulated in the livers of ADSB mice. The inducible mouse model of humanized liver in ADSB mice may have functional applications,such as hepatocyte transplantation,hepatic regeneration and drug metabolism.
基金supported by grants from the Science and Technology Foundation of Guizhou Province of China(Grant No.[2019]1185).
文摘Aim:Pertussis is a respiratory tract infection,the vaccine for which was introduced in the Expanded Programme on Immunization(EPI)in Guizhou Province of China(hereafter referred as Guizhou)in the 1980s.This vaccine rapidly decreased incidence rates of pertussis in the province,however,despite the wide high coverage of the diphtheria,tetanus and acellular pertussis(DTaP)combined vaccine,there has been a resurgence of pertussis since 2014.Even with this recent increase in disease transmission,risk factors for pertussis infection have not been evaluated in Guizhou.We aimed to provide information on pertussis risk factors and insight on designing targeted pertussis control policies and measures through this study.Methods:A 1:2 matched retrospective case-control study was conducted between 2016 and 2017,involving infants and children younger than 6 years old and parents of the participants.The enrolled cases included clinical and laboratory confirmed pertussis cases according to the WHO-recommended pertussis definition.Controls were selected from children in the same neighborhood who were not diagnosed with pertussis prior to our investigation and did not exhibit any clinical manifestations of pertussis.Results:The household size[Matched odds ratio(OR_(m)=1.4,95%confidence interval(Cl):1.1-1.7]and household members with antecedent cough(OR_(m)=3.6,95%CI:1.8-7.2)were significantly associated with their child’s pertussis onset.The parents’occupations were significantly associated with their child’s pertussis onset(ORm=9.4,95%CI:1.6-54.8,for mother side;ORm=4.5,95%CI:1.2-16.5,for father side),when they worked in the business and/or service industry.Having family members with a history of cough was an independent risk factor for pertussis[Adjusted odds ratio(AOR)=43.6,95%CI:2.7-694.0].Besides,the parents’demographic characteristics and DTaP doses were not found to be independent factors.Conclusion:Household exposure is an important risk factor for pertussis infection in infants and young children and should therefore be considered as a major factor during formulation of pertussis control policies and measures.
文摘Three diphtheria toxin (DT) mutants CRM-197, DT-del (148) and DT-El48S-K516A-F530A were cloned in B- Subtilis plasmid PSM604 under the subtilisin signal sequence. The expression was effective in both SMS300 and SMS118, but higher yield of 7. 1 mg/L was observed in SMS300 compared with 2. 1 mg/L in SMS118. Western blot showed that the recombinant protein could be effectively secreted into the culture medium as a 58 ku peptide, and could be de-graded into two peptides of 37ku and 21ku.
基金supported by grants from the National "973" Basic Research Program of China (No.2012CB944703)the National Key Technology Research and Development Program of China (No.2011BAI17B00)the Shandong Provincial Science and Technology Development Projects (No.2009GG10002008 and No.2011GSF12103)
文摘Objective： This study aimed to express a fusion protein of diphtheria toxin and human B cell-activating factor （DT388sBAFF） in Escherichia coli （E. coli） and investigate its activity in human B-lineage acute lymphoblastic leukemia 1 cells （BALL-1）. Methods： A fragment of DT388sBAFF fusion gene was separated from plasmid pUC57-DT388sBAFF digested with Nde I and Xho I, and inserted into the expression vector pcold II digested with the same enzymes. Recombinants were screened by the colony polymerase chain reaction （PCR） and restriction map. The recombinant expression vector was transformed into BL21 and its expression was induced by isopropyl β-D-1-thiogalactopyranoside （IPTG）. The recombinant protein was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE） and Western blot, and then purified by Ni2＋-NTA affinity chromatography. The expression level of B cell-activating factor receptor （BAFF-R） on BALL-1 cells was assessed by real-time PCR. The receptor binding capacity of recombinant protein was determined by cell fluorescent assay. The specific cytotoxicity of recombinant protein on BALL-1 cells was detected by 3-（4,5-dimethylthiazolyl-2）-2,5-diphenyltetrazolium bromide （MTT） assay. Results： The expression level of recombinant protein was 50% of total bacterial proteins in E. coli, and the recombinant protein could bind to BAFF-R-positive BALL-1 cells and thereby produce a cytotoxic effect on the cells. Conclusion： The fusion protein expression vector DT388sBAFF was successfully constructed and the recombinant protein with selective cytotoxicity against BALL-1 cells was obtained, providing foundation for further study of the therapy of human B-lineage acute lymphoblastic leukemia.
基金Health Department Scientific Research Foundation of Hubei province (No. NX200501)
文摘Objective: To study the effects of recombinant expression vector containing human breast cancer DF3 promotor and diphtheria toxin A fragment on human breast cancer cells. Methods: Constructing recombinant expression vector PGL3-DF3-DTA and transfecting it into human breast cancer cells of DF3 positive and negative. By means of RT-PCR to measure the expression of DTA in human breast cancer cells. MTT color-imetry was used to examine the effect of PGL3-DF3-DTA on growth of human breast cancer cells. By experiment on nude mice to observe the killing effect of PGL3-DF3-DTA on human breast cancer cells. Results: Recombinant expression vector PGL3-DF3-DTA was highly expressed in human breast cancer cell line of DF3 positive, and it could kill the human breast cancer cells not only in vitro but also in vivo. Conclusion: Recombinant expression vector PGL3-DF3-DTA could produce specific killing effect on human breast cancer cell line of DF3 positive.
文摘Despite effective vaccines, diphtheria (D) resurged recently in the former socialistic block, and tetanus (T) still occurs in less privileged countries. We studied the antibody persistence for D and T in Indian pre-school children who had received four doses of DTP vaccine and subsequently, the response to a booster dose. Anti-D and anti-T IgG antibodies prior to and one month after a DT vaccine were measured by ELISA in 223 healthy children of 4-6 years who had previously received four doses of the triple vaccine. Adverse reactions were monitored for one month. While 30% and 14% of subjects were susceptible to D and T, respectively, 98% and 100% of them attained seroprotection post-vaccination. Both responses were significant. Local, but not systemic reactions except fever were rather common. A high proportion of the Indian pre-school population is susceptible to D and T, despite of receiving four doses. The current policy of giving the fifth dose at this age is appropriate.
文摘Background: Diphtheria is still endemic in India due to inadequate immunization. The incidence of myocarditis is higher in these patients. Objectives: The objective of this study was to study clinical profile, clinical outcomes as well as immunization status of the patients diagnosed with diphtheria myocarditis in Indian scenario. Methodology: This prospective observational study was carried out in one of the tertiary care hospital of south India from August 2011 to December 2012. A total of 33 cases with clinically confirmed diagnosis of diphtheria myocarditis were enrolled depending upon the inclusion and exclusion criteria of the study. Electrocardiography and 2-dimensional echocardiography was done at the time of admission and repeated when required. Results: The most common age group affected is 5 - 10 years, with no sex difference in occurrence. Only 1 patient, out of 33 patients, was adequately immunized. Asymptomatic myocardial involvement (with only changes in electrocardiogram) was seen in 21 patients whereas 12 patients were symptomatic. The average duration of resolution of electrocardiographic changes was 4 - 6 weeks. It should be noted that out of 28 patients who developed conduction abnormalities, 24 patients died. Temporary pacemaker support was given for 8 patients, of whom only one patient recovered. The patient was followed till hospital discharge. Conclusion: The mortality associated with diphtheria myocarditis is higher in Indian population. As diphtheria can be prevented by adequate vaccination, efforts should be maximized for 90% coverage with three doses of diphtheria toxoid in children below one year of age and immunity towards it should be maintained by booster doses.
基金Research supported by Bio-Manguinhos/FIOCRUZ,PAPES II/FIOCRUZ,FAPERJ,CNPq,CAPES,Programa de Núcleo de Excelencia(PRONEX/MCT/CNPq).
文摘The genetic modification of the live attenuated Mycobacterium bovis BCG to deliver a protective Corynebacterium diphtheriae antigen in vivo could be a safer and less costly alternative to the new and more expensive DTP vaccines available today, in particular to third world-countries. The stability of expression of heterologous antigens in BCG, however, is a major challenge to the use of live recombinant bacteria in vaccine development and appears to be dependent to a certain extent, on a genetic compatibility between the expression cassette within the plasmid construct and the mycobacterium host. In the quest for the best recombinant BCG transformant to express the dtb gene of C. diphtheriae we generated two new rBCG strains by transforming the Moreau substrain of BCG with the mycobacterial expression vectors pUS973 and pUS977, each one carrying a different promoter to drive the expression of the target antigen. After transformation recombinant BCG clones were selected on Middlebrook 7H10 kanamycin Agar plates, expanded in Middlebrook 7H9 kanamycin Broth and analyzed by agarose gel electrophoresis and immunoblotting. rBCGs transformed with the construct carrying the weak PAN promoter from M. paratuberculosis stably expressed the dtb gene. Conversely, rBCGs transformed with the construct carrying the strong mycobacterium hsp60 promoter were unstable and consequently unfit for the expression of the C. diphtheriae gene.
文摘Background Diphtheria,caused by Corynebacterium diphtheriae,remains a serious public health threat in areas with low vaccination coverage,despite global declines due to widespread immunization and improved clinical management.A major outbreak in Nigeria from 2022 to 2023 underscored the persistent risk in regions with inadequate vaccination.This study aims to assess the transmission dynamics of diphtheria in Kano State,the epicenter of the outbreak,by estimating key epidemiological parameters,including the generation time(GT),approximated in our study by serial interval,and effective reproduction number(R).Methods We analyzed diphtheria case-based data from Kano State,Nigeria,collected between August 18,2022,and November 29,2023.Generation time was approximated using serial intervals in confirmed cases within the same geographical areas.The effective reproduction number(R)was calculated using four methods:Maximum Likelihood Estimation(MLE),Exponential Growth(EG),Sequential Bayesian(SB),and Time-Dependent(TD),focusing on the period of maximum exponential growth.A sensitivity analysis was conducted to quantify the impact of uncertainties in the GT derived from our data on the estimation of R.Results Over the 469-day outbreak period,13,899 diphtheria cases were reported,with complete data available for 9406 cases.The estimated mean generation time was 2.8 days(SD=3.48 days),with 97%of cases having a GT of less than 21 days.The Restimates varied across methods,with the TD method producing the highest reproduction number of 2.21 during the peak growth period.Sensitivity analysis showed that Restimates increased with longer generation times.The models,except for the SB method,demonstrated a generally strong fit with the outbreak exponential growth period.Conclusion The ongoing diphtheria outbreak in Nigeria highlights the critical threat posed by declining vaccination coverage.This study provides valuable insights into the transmission dynamics of diphtheria during a prolonged and widespread outbreak,enhancing our understanding of disease spread in this context.While certain limitations may influence the interpretation of our estimates,the findings offer valuable information for future diphtheria outbreak preparedness and response in the African context.
文摘OBJECTIVE: To test whether the diphtheria toxin A (DT-A) chain coding sequence linked to murine immunoglobulin Kappa light chain (IgKappa) promoter and enhancer have selective cytocidal effects on IgKappa producing cells. METHODS: The diphtheria toxin A gene or beta galactosidase (beta-gal) gene were linked to a murine IgKappa promoter and enhancer to construct pcDNA3IgKappaDTA or pcDNA3IgKappaLacZ plasmids. These plasmids were transfected into IgKappa producing or non-producing cells by the liposome coated DNA method. Expression of beta-gal activity and effects on cell growth of transfected cells were assessed. RESULTS: The beta-gal gene, under the control of cytomegalovirus (CMV) promoter, can express in all cell lines. Expression of beta-gal under the control of the IgKappa promoter was detected only in the IgKappa producing cell line, CA46. Expression of beta-gal was greatly suppressed when cotransfected with pcDNA3IgKappaDTA in CA46 cells.Cell growth of CA46 cells transfected with pcDNA3IgKappaDTA plasmid was significantly inhibited compared with CA46 cells transfected with pcDNA3IgKappaLacZ. CONCLUSION: Selective killing of IgKappa producing cells can be attained by introducing the diphtheria toxin A gene under the control of IgKappa promoter and enhancer.
基金supportedby Shanghai Municipal Natural Science Foundation(No.17ZR1406600,China)Science and Technology Commission of Shanghai Municipality(No.10DZ2220500,China)+1 种基金The Shanghai Committee of Science and Technology(Grant No.11DZ2260600,China)National Natural Science Foundation of China(Grant No.81973700)
文摘A light-switchable transgene system called LightOn gene expression system could regulate gene expression with a high on/off ratio under blue light,and have great potential for spatiotemporally controllable gene expression.We developed a nanoparticle drug delivery system(NDDS)to achieve tumor microenvironment-responsive and targeted delivery of diphtheria toxin A(DTA)fragment-encoded plasmids to tumor sites.The expression of DTA was induced by exposure to blue light.Nanoparticles composed of polyethylenimine and vitamin E succinate linked by a disulfide bond,and PEGylated hyaluronic acid modified with RGD peptide,accumulated in tumor tissues and were actively internalized into 4 T1 cells via dual targeting to CD44 andαvβ3 receptors.The LightOn gene expression system was able to control target protein expression through regulation of the intensity or duration of blue light exposure.In vitro studies showed that lisht-induced DTA expression reduced 4 T1 cell viability and induced apoptosis.Furthermore,the LightOn gene expression system enabled spatiotemporal control of the expression of DTA in a mouse 4 T1 tumor xenogratt model,which resulted in excellent antitumor effects,reduced tumor angiogenesis,and no systemic toxicity.The combination of the LightOn gene expression system and NDDS may be an effective strategy for treatment of breast cancer.
文摘2013年10月,美国免疫实施咨询委员会（Advisory Committee on Immunization Practices,ACIP）推荐2-23月龄处于感染脑膜炎球菌疾病高风险的儿童接种A、C、Y和W135群脑膜炎球菌多糖-白喉类毒素变异体结合疫苗[Meningococcal Polysaccharide Groups A,C,Y and W135 Conjugate Vaccine-Diphtheria Toxin（DT）Mutant Cross ReactingMaterial，MPCV4．CRM（商品名：Menveo，诺华疫苗公司）]。
文摘Background Certain infectious diseases are caused by specific bacterial pathogens,including syphilis,gonorrhea,typhoid and paratyphoid fever,diphtheria,pertussis,tetanus,leprosy,and tuberculosis.These diseases significantly impact global health,contributing heavily to the disease burden.The study aims to thoroughly evaluate the global burden of syphilis,gonorrhea,typhoid and paratyphoid fever,diphtheria,pertussis,tetanus,and leprosy.Methods Leveraging the Global Burden of Disease(GBD)study 2021,age-specific and Socio-demographic Index(SDI)-specific incidence,disability-adjusted life-years(DALYs),and death for eight specific bacterial infections across 204 countries and territories from 1990 to 2021 were analyzed.Percentage changes in age-standardized incidence rate(ASIR),DALY rate,and mortality rate(ASMR)were also examined,with a focus on disease distribution across different regions,age groups,genders,and SDI.Results By 2021,among the eight diseases,gonococcal infection had the highest global ASIR[1096.58 per 100,000 population,95%uncertainty interval(UI):838.70,1385.47 per 100,000 population],and syphilis had the highest global age-standardized DALY rate(107.13 per 100,000 population,95%UI:41.77,212.12 per 100,000 population).Except for syphilis and gonococcal infection,the age-standardized DALY rate of the remaining diseases decreased by at least 55%compared to 1990,with tetanus showing the largest decrease by at least 90%.Globally,significant declines in the ASIR,age-standardized DALY rate,and ASMR for these eight bacterial infections have been observed in association with increases in the SDI.Regions with lower SDI,such as sub-Saharan Africa,experienced a relatively higher burden of these eight bacterial infections.Conclusions Although there has been an overall decline in these eight diseases,they continue to pose significant public health challenges,particularly in low SDI regions.To further reduce this burden in these areas,targeted intervention strategies are essential,including multi-sectoral collaboration,policy support,improved WASH management,and enhanced research efforts.
基金Project supported by the National Natural Science Foundation of China
文摘A new approach of polarographlc immunoassay based on the catalytic amplification of the labeled metal ions and the polarographlc detection of the catalytic product was developed.In this approach,the copper ions used as the catalyst for substrate conversion instead of natural enzyme were labeled to model antigen diphtheria toxoid (DT) through the bifunctional chelating reagent diethylenetriamine pentaacetic acid (DTPA).After heterogeneous competitive imrnunoreaction,the oxidation of substrate o-phenylenediatnine (OPD) was catalyzed by the labeled copper ions to generate an electroactive product 2,3-diammophenazine (DAP); subsequently,the product DAP was detected with linear-sweep polarography The proposed assay can determine the concentration in the range of 10-1 000 ng/mL of DT,two orders of magnitude more sensitive than those based on the direct detection of the metal ion labels The proposed immunoassay can be applied to detecting various proteins of interest.
基金funded by Institut Teknologi Bandung(Research Grant ITB 2024).
文摘The COVID-19 pandemic caused significant disruptions in the healthcare system,affecting vaccinations and the management of diphtheria cases.As a consequence of these disruptions,numerous countries have experienced a resurgence or an increase in diphtheria cases.West Java province in Indonesia is identified as one of the high-risk areas for diphtheria,experiencing an upward trend in cases from 2021 to 2023.To analyze the situation,we developed an SIR model,which integrated DPT and booster vaccinations to determine the basic reproduction number,an essential parameter for infectious diseases.Through spatial analysis of geo-referenced data,we identified hotspots and explained diffusion in diphtheria case clusters.The calculation of R0 resulted in an R0=1.17,indicating the potential for a diphtheria outbreak in West Java.To control the increasing cases,one possible approach is to raise the booster vaccination coverage from the current 64.84%to 75.15%,as suggested by simulation results.Furthermore,the spatial analysis revealed that hot spot clusters were present in the western,central,and southern regions,posing a high risk not only in densely populated areas but also in rural regions.The diffusion pattern of diphtheria clusters displayed an expansion-contagious pattern.Understanding the rising trend of diphtheria cases and their geographic distribution can offer crucial insights for government and health authorities to manage the number of diphtheria cases and make informed decisions regarding the best prevention and intervention strategies.
