Objective To establish and modify quantitative real-time polymerase chain reaction(qPCR)-based serotyping assays to distinguish 97 pneumococcal serotypes.Methods A database of capsular polysaccharide(cps)loci sequence...Objective To establish and modify quantitative real-time polymerase chain reaction(qPCR)-based serotyping assays to distinguish 97 pneumococcal serotypes.Methods A database of capsular polysaccharide(cps)loci sequences was generated,covering 97 pneumococcal serotypes.Bioinformatics analyses were performed to identify the cps loci structure and target genes related to different pneumococcal serotypes with specific SNPs.A total of 27 novel qPCR serotyping assay primers and probes were established based on qPCR,while 27 recombinant plasmids containing serotype-specific DNA sequence fragments were constructed as reference target sequences to examine the specificity and sensitivity of the qPCR assay.A panel of pneumococcal reference strains was employed to evaluate the capability of pneumococcal serotyping.Results A total of 97 pneumococcal serotyping assays based on qPCR were established and modified,which included 64 serotypes previously reported as well as an additional 33 serotypes.Twenty-seven novel qPCR serotyping target sequences were implemented in the pneumococcal qPCR serotyping system.A total of 97 pneumococcal serotypes,which included 52 individual serotypes and 45 serotypes belonging to 20 serogroups,could not be identified as individual serotypes.The sensitivity of qPCR assays based on 27 target sequences was 1–100 copies/μL.The specificity of the qPCR assays was 100%,which were tested by a panel of 90 serotypes of the pneumococcal reference strains.Conclusion A total of 27 novel qPCR assays were established and modified to analyze 97pneumococcal serotypes.展开更多
BACKGROUND Extended-spectrumβ-lactamase(ESBL)-producing Escherichia coli(E.coli)are among the main pathogens in urinary tract infections(UTIs)among kidney transplant patients(KTPs).AIM To estimate the prevalence of E...BACKGROUND Extended-spectrumβ-lactamase(ESBL)-producing Escherichia coli(E.coli)are among the main pathogens in urinary tract infections(UTIs)among kidney transplant patients(KTPs).AIM To estimate the prevalence of ESBL-producing E.coli in KTPs and to evaluate the most prevalent serotypes and antibacterial susceptibility patterns of isolated bacteria in Tehran,Iran.METHODS A total of 60 clinical isolates of uropathogenic E.coli were collected from 3 kidney transplant centers from April to May 2019.Antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the Clinical Laboratory and Standards Institute.The serotyping of E.coli isolates was performed by the slide agglutination method.The presence of blaTEM,blaSHV,and bla CTX-M genes was evaluated by polymerase chain reaction.RESULTS The frequency of ESBL-producing E.coli in KTPs was found to be 33.4%.All of the 60 E.coli isolates were found to be susceptible to doripenem(100%)and ertapenem(100%).High resistance rates to ampicillin(86%),cefotaxime(80%),and cefazolin(77%)were also documented.The most frequent serotypes were serotype I(50%),serotype II(15%),serotype III(25%),and serotype VI(10%).The gene most frequently found was blaTEM(55%),followed by blaCTX-M(51%)and blaSHV(41%).CONCLUSION Molecular analysis showed that blaTEM was the most common ESBL-encoding gene.The high resistance toβ-lactams antibiotics(i.e.,ampicillin,cefotaxime,and cefazolin)found in E.coli from KTPs with UTIs remains a serious clinical challenge.Further efforts to control ESBL-producing E.coli should include the careful use of all antibiotics as well as barrier precautions to reduce spread.展开更多
Bovine Respiratory Disease (BRD) causes a severe form of pneumonia in all age of cattle. This study was designed to investigate the distribution of capsular types, serotypes, and virulence-associated genes of the majo...Bovine Respiratory Disease (BRD) causes a severe form of pneumonia in all age of cattle. This study was designed to investigate the distribution of capsular types, serotypes, and virulence-associated genes of the major bacterial pathogens from BRD outbreak samples in Ethiopia. In this study 166 samples were collected from clinically sick (<i>n</i> = 107) and pneumonic lung tissue (<i>n</i> = 59). Laboratory assay confirmed isolation of <i>M. haemolytica</i> 37 (22.29%), <i>P. multocida</i> 25 (15.06%), <i>B. trehalosi</i> 12 (7.23%), and <i>H. somni</i> 15 (9.04%). PCR assay of <i>P. multocida</i> capsular typing revealed 21 (84.0%) cap A (<i>hyaD-hyaC</i>) and 4 (16.0%) cap D (<i>dcbF</i>) strains. <i>M. haemolytica</i> serotypes belonged to A: 1, A: 2, and A: 6 from 26 (70.27%), 4 (10.81%), and 7 (18.92%) isolates, respectively. <i>P. multocida</i> biotyping showed isolation of A: 1, A: 2, and A: 3 from 3 (14.29%), 2 (9.52%), and 16 (76.19%) isolates, respectively. <i>M. haemolytica</i> harbored more than 60% <i>ssa</i> gene, and 90.91% <i>sodA</i> while <i>FbpA</i>, <i>TbpA</i>, and <i>lktC</i> genes were found in all isolates. Likewise, all <i>P. multocida</i> exhibited <i>toxA</i>, <i>FbpA</i>, <i>TbpA</i>, and <i>pmSLP</i> genes. The current finding showed that <i>M. haemolytica</i> serotype A: 1 is frequently associated with BRD followed by <i>P. multocida</i> biotype A: 3. These two isolates harbored diverse virulence-associated genes and presented the pathogenic potential of the current isolates. Thus, investigation of pathogenic strains of BRD, virulence genes distribution, and molecular epidemiology of the disease from wider areas of the country are essential. Hence, continuous outbreak surveillance and molecular approaches are indispensable in designing efficient prevention strategies.展开更多
Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different...Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.展开更多
Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selecte...Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.展开更多
Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence ...Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence of preexisting anti-vector immunity compromises the immunogenicity of Ad5-based vaccines.Thus,there is a substantial unmet need to minimize preexisting immunity while improving the insert-induced immunity of Ad5 vectors.Herein,we address this need by utilizing biocompatible nanoparticles to modulate Ad5–host interactions.We show that positively charged human serum albumin nanoparticles((+)HSAnp),which are capable of forming a complex with Ad5,significantly increase the transgene expression of Ad5 in both coxsackievirus–adenovirus receptor-positive and-negative cells.Furthermore,in charge-and dose-dependent manners,Ad5/(+)HSAnp complexes achieve robust(up to227-fold higher)and long-term(up to 60 days)transgene expression in the lungs of mice following intranasal instillation.Importantly,in the presence of preexisting anti-Ad5 immunity,complexed Ad5-based Ebola and COVID-19 vaccines significantly enhance antigen-specific humoral response and mucosal immunity.These findings suggest that viral aggregation and charge modification could be leveraged to engineer enhanced viral vectors for vaccines and gene therapies.展开更多
and pili genes are also investigated.Methods:This multicentre,prospective,observational study is conducted in seven major tertiary hospitals in Malaysia among non-pregnant adults.Simultaneously,a retrospective study i...and pili genes are also investigated.Methods:This multicentre,prospective,observational study is conducted in seven major tertiary hospitals in Malaysia among non-pregnant adults.Simultaneously,a retrospective study is conducted in the selected hospitals with similar approaches.GBS isolates are subjected to phenotyping,serotyping by multiplex PCR,antimicrobial susceptibility testing and PCR-detection of GBS virulence and pilus genes.Seven housekeeping genes are amplified and sequenced for multi-locus sequence typing.Discussion:Findings from the study may contribute to the management of clinical practice to diagnose and prevent GBS related diseases in a timely manner.Prudent use of antibiotics is encouraged by monitoring antimicrobial resistance.展开更多
Background: The main objective of this study is to describe the rate of the different serotypes of HPV in cervical cytologies and biopsies in three different periods: 2002-2006 (prior to the implementation of the vacc...Background: The main objective of this study is to describe the rate of the different serotypes of HPV in cervical cytologies and biopsies in three different periods: 2002-2006 (prior to the implementation of the vaccination programs in Spain), 2009-2011 (shortly after this implementation) and 2020 (almost 15 years after introduction of the vaccine) at a single hospital. Methods: This is an observational, descriptive, retrospective study based on the review of the results of the determination of the HPV serotype using the commercial kit (Genomica<sup>®</sup>;PharmaMar LTD) in cervical liquid-based cytologies and biopsies at a single large tertiary hospital, Hospital Clínico San Carlos, in Madrid, Spain. We have collected the data from three different time periods: 2002-2006;2009-2011, and 2020 to try to understand the potential changes associated with the use of the vaccine. Results: In these time periods we have reviewed the data from 1420 women. In the three periods the most frequent serotype was HPV 16, followed by HPV 18 or a combination of both. The most frequent low risk serotype was HPV 6 followed by the combination of HPV 6 and 11. It has been verified in our study that the prevalence of the category “others”, constituted by the three risk groups, has undergone a progressive increase, beginning with an infection rate of 65.43% in 2002-2006 to finally rise up to 90.92% in the year 2020. Conclusions: Our study reveals an increase in the number of infections by the HPV serotypes that are not included in the tetravalent vaccine.展开更多
Background: The main objective of this study is to analyse the change in the type of lesions developed by HPV-infected patients after the introduction of the vaccine in three different periods;2002-2006 (years previou...Background: The main objective of this study is to analyse the change in the type of lesions developed by HPV-infected patients after the introduction of the vaccine in three different periods;2002-2006 (years previous to the implementation of the vaccine in Spain), 2009-2011 (shortly after the vaccination) and 2020-2021 (years where the vaccine was well established) at a single hospital. Methods: This is an observational, descriptive, retrospective study based on the review of the results of the biopsies of patients with HPV lesions at a single large tertiary hospital, Hospital Clínico San Carlos, in Madrid, Spain. We have collected the data from three different time periods: 2002-2006, 2009-2011, 2020-2021 to try to understand the potential changes in these lesions after vaccine introduction. Results: In this time we have reviewed the data from 946 women. In these three periods, a decreasing trend in the rate of squamous cell carcinoma was noted, the rate of adenocarcinoma remains stable, and the rate of cervical intraepithelial neoplasia grades 2 - 3 (CIN 2-3) lesions shows an increasing trend. We have also found a change in the mean ages of the patients with these lesions, as this increased in the three lesions caused by HPV after the implementation of the vaccine. Our study indicates that the identification of other high risk serotypes, apart from 16 and 18, as well as those with indeterminate risk, has undergone a progressive increase, increasing from 24.24% and 14.11% respectively in 2002-2006 to 40.42% and 28.34% in 2020-2021. Conclusion: Our study confirms the effectiveness of the vaccines developed so far, against the HPV serotypes they contain. This is demonstrated by the evidence, in our population, of a decrease in the incidence of squamous cell carcinoma in uterine cervix. In parallel, an increase in the mean age of diagnosis has been verified, for both squamous cell carcinoma and its CIN 2-3 precursor lesions, as well as a change in the infective trend of HPV serotypes that are not included in the current vaccines.展开更多
Nutritional value of vegetables and high prices of meat and meat originated food compel common people to consume plant originated food particularly salad vegetables. Microbial population of vegetable surfaces contains...Nutritional value of vegetables and high prices of meat and meat originated food compel common people to consume plant originated food particularly salad vegetables. Microbial population of vegetable surfaces contains a large number of pathogenic bacteria including members of Enterobactereace like Escherichia coli (E. coli). A survey was conducted in three major markets of Rawalpindi, Pakistan. Tomato, lettuce, cabbage and cucumber samples were collected from three shops of each market. Each vegetable was analysed as unwashed and washed for total coliforms, faecal coliforms and E. coli by FAO (Food Quality Manual). About two hundred and fifty E. coli isolates were preserved, serotyped for presence of O157 serotype. Total coliforms, faecal coliforms and E. coli count exceeded the permissible limits in most samples. The highest Total coliforms were associated with cabbage (3.78 log10 cfu/g). Cucumber was the least contaminated by Total coliforms (2.15 log10 cfu/g). E. coli was detected in tomato, lettuce, cucumber and cabbage. Washed samples showed reduced bacterial population. Seventy six isolates of E. coli were biochemically characterized and serotyped for O157 antigen. A majority of strains could not be identified by serotyping. These findings conclude with high potentially pathogenic microbial load on salad vegetables and urge for preventive action on priority basis.展开更多
Campylobacter is one of the most common bacterial enteropathogens of food borne origin in industrialized countries with C. jejuni being the most common species followed by C. coli. The prevalence of Campylobacters in ...Campylobacter is one of the most common bacterial enteropathogens of food borne origin in industrialized countries with C. jejuni being the most common species followed by C. coli. The prevalence of Campylobacters in and around Chandigarh, India was studied by phenotypic and genotypic methods. Fecal samples from 1145 diarrheal patients and 102 healthy subjects from hospital and community were cultured on Campylobacter media and identified by Gram stain, biochemical investigations and serotyping. Molecular identification of Campylobacter isolates was done using specific primers to unique regions of 16S rRNA, Campylobacter jejuni (hipO), Campylobacter coli (aspK), Campylobacter lari (glyA) and Campylobacter upsaliensis (lpxA) genes. Identification of specific genes to look for resistance to nalidixic acid, ciprofloxacin, tetracyclin and streptomycin was also done. Campylobacters were isolated from 2.6% of patients with diarrhea. Campylobacteriosis was more prevalent in children ≤5 years old and during summer season. The most frequent serotypes were S:27, B:2, Z5:52 and V:32. All the Campylobacters isolated by culture were confirmed genotypically by identification of 16S rRNA, hipO and aspK genes. Of the 30 isolates, 27 were C. jejuni and 3 were C. coli. No C. lari or C. upsaliensis were detected. Antibiotic resistance was 40% for nalidixic acid, 23.3% for ciprofloxacin, 50% for tetracyclin and 20% for streptomycin. Campylobacter prevalence is low in the region with C. jejuni being the most common species. A high degree of resistance was found for nalidixic acid and tetracyclin but moderate for ciprofloxacin and streptomycin.展开更多
Campylobacter is one of the most common food-borne bacterial enteropathogens. We planned to investigate the prevalence and antibiotic resistogram of Campylobacter in poultry in and around Chandigarh. Poultry samples (...Campylobacter is one of the most common food-borne bacterial enteropathogens. We planned to investigate the prevalence and antibiotic resistogram of Campylobacter in poultry in and around Chandigarh. Poultry samples (n = 127) were obtained from slaughter houses/retail outlets and cultured microaerophilically on Campylobacter media. The isolates were identified phenotypically and by molecular investigation. Identification of specific genes to look for resistance to nalidixic acid, ciprofloxacin, tetracyclin and streptomycin was also done. Campylobacter was isolated from 57/127 (44.9%) of the samples. The most frequent serotypes identified were B: 2, S: 27, Z5: 52 and Z7: 57. All culture isolates (100%) were reconfirmed as Campylobacter by 16S rRNA polymerase chain reaction. Molecular identification of isolates revealed the presence of C. jejuni in 45 (79.0%), C. coli in 1 (1.8%) and co-infection of C. coli and C. jejuni in 11 (19.3%). No C. lari and C. upsaliensis were detected. Antibiogram typing showed nalidixic acid resistance in 36.8%, ciprofloxacin resistance in 35.0% and 31.5% resistance for both streptomycin and tetracyclin. A high level of Campylobacter prevalence was found among the poultry with C. jejuni being the most commonly isolated species. Resistance to major antibiotics among Campylobacter isolates from poultry was also very high. The study of prevalence of Campylobacter in poultry and its resistance to major antibiotics will help to plan risk burden strategies throughout the food chain.展开更多
AIM: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains.METHODS: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with...AIM: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains.METHODS: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with the corresponding sequence in other strains. Salmonella strains including two typhi strains, one paratyphoid strain, one enteritidis and one typhimurium strain were isolated from outpatients. Genome DNA was purified respectively from these clinical isolstes, then the corresponding flagellin C fragment was amplified by polymerase chain reaction, and the amplification products were analyzed by agarose gel electrophoreeis.RESULTS: The cloned fragment includes 582 nucleotides encoding the variable region and partial conservative region of Salmonella flagellin C in plasmid pLS408. With comparison to the corresponding sequences reported previously, there is only a little difference from other strains with the same flagellar serotype in both nucleotide and amino acid level. Specific PCR products were amplified in Salmonella strains with flagellar eerotype H-1-d including S. Muenchen, typhi and typhimurium, but not in S.paratyphoid C or S. Enteritidis strains.CONCLUSION: In this experiment, the specificity of nucleotide sequence could be found in flagellin C central variable regions as it exists in flagellar serotypes in Salmonella. It may be helpful to developing a rapid,sensitive, accurate and PCR-based method to detect Salmonella strains with serotype H-1-d.展开更多
Objective:To identify the circulating serotypes of human echovinis in Malaysia from 2002 in 2013.Methods:A toial of 31 retrospective samples from non-polio acute flacid paralysis,hand-food-and-mouth disease,viral meni...Objective:To identify the circulating serotypes of human echovinis in Malaysia from 2002 in 2013.Methods:A toial of 31 retrospective samples from non-polio acute flacid paralysis,hand-food-and-mouth disease,viral meningitis and enterovirus cases were subjected to amplification of partial VPI gene by RT-PCR.Results:Sequencing and phylogeneiic analysis of the partial sequences identified presence of human echovinis and human coxsackie viruses.It was found that echovinis 11 was the commonly circulating serotype followed by echovinis6.echovinis 7.echovinis 3.echovinis 9.echovinis 30 and echovinis I in decreasing order.Additionally two types of human coxsackie virus isolates were detected which were coxsackie A24 and B3.Condusions:From the findings,there is a possibility that echovinis 11 is the predominant serotype among Malaysian patients with echovinis infection.However,a larger sample size will yield a more confident result to support this evidence.____________________展开更多
Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculo...Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculovirus expression system to develop candidate subunit vaccines.However,the protective efficiency of baculovirus-expressed penton base protein has not been assessed.In this study,two recombinant capsid proteins,penton base and fiber-2,were constructed.And then,penton base and fiber-2 were administrated alone or together to specific pathogen-free(SPF)chickens at 14 days of life and boosted at 28 days of life.At 42 days of life,the immunized groups and the control group were challenged with FAdV-4 virulent strain.Results show that inoculating penton base or penton base+fiber-2 provided 100%protection to the chickens.All groups vaccinated with the recombinant protein produced detectable antibodies and showed no apparent lesions.Thus,baculovirus-expressed penton base protein is a promising candidate subunit vaccine.展开更多
BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following ...BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following the introduction of EV-A71 vaccines in China since 2016,the situation could change.CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China.However,the epidemiological characteristics of central China remain unknown.AIM To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City,central China,in recent years.METHODS The epidemiological,clinical,and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed.196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020.To detect and genotype enteroviruses,real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used.In Shiyan,168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes.Based on the logistic regression model,the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.RESULTS From 2016 to 2020,35840 HFMD cases were reported in Shiyan.The number of cases decreased by 48.4%from 2016 to 2017.Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year,respectively.In 2020,a decrease of about 85.5%was reported when compared to 2019.The most common serotypes shifted from EV-A71 and CV-A16(about 60%-80%in 2016 and 2018)to others(more than 80.0%in 2017,2019,and 2020).EV-A71 lost its dominance in 2017 in Shiyan.Among 196 confirmed HFMD cases,85.7%tested positive for enterovirus,with CV-A6 being the most common serotype(121/168,72.0%).The positive rates for CV-A16 and CVA10 were 4.8%and 3.0%,respectively.There was no EV-A71 discovered.Infection with CV-A6 was linked to fever,myocardial damage,increased creatine kinase MB isoenzyme,and lactate dehydrogenase levels.CONCLUSION CV-A6 was the most common enterovirus serotype in Shiyan City,replacing EV-A71 and CV-A16 as the HFMD pathogen.Developing vaccines against CV-A6 or multiple pathogens,as well as rising CV-A6 surveillance,will help prevent HFMD in central China.展开更多
Streptococcus suis is one of the major pathogens of swine streptococcosis. Among them, the strongest virulence and highest rate of clinical isolation serotype is S. suis serotype 2(SS2). Moreover, SS2 is also an impor...Streptococcus suis is one of the major pathogens of swine streptococcosis. Among them, the strongest virulence and highest rate of clinical isolation serotype is S. suis serotype 2(SS2). Moreover, SS2 is also an important zoonosis pathogen, which caused severe public health issues in China. It has been reported that SS2 has several virulence factors, including muramidase released protein, extracellular factors, capsule, fibronectin-binding protein, enolase, hemolysin, small RNA, biofilm, two-component regulatory systems, STK/STP, etc., whose functions involved in adhesion, anti-phagocytosis, inflammatory pathway activation, invasion, etc. Actually, SS2 has developed a variety of ways to escape from host immune system during evolution. In particularly, capsule could resist phagocytosis through inhibiting sphingosine dependent immune cell recognition, which plays an important role in escaping host inflammation response; moreover, superoxide dismutase encoding by sod A enables SS2 escaping reactive oxygen species(ROS) in host immune cells; besides, binding complement factor h with Fhb could suppress the activation of complement alternative pathway and bactericidal effect. And SS2 could also hinder the formation of neutrophil extracellular traps(NETs) to avoid trapping by swine neutrophils, while host immune globulin could be degraded by Ig A1 hydrolase and Ig M protease. In addition, SS2 could escape host immune defense with the help of multiple transcriptional factors and micro-RNA. So far, the pathogenesis of meningitis, arthritis caused by SS2 infection, is still unclear, and the virulence regulatory mechanism of phosphorylation, micro-RNA need to be further clarified. Importantly, the study of interaction mechanism of pathogen and host contribute to further demonstration the pathogenesis of SS2.展开更多
Objective: To ascertain the role of imported cases and serotypes on dengue outbreaks in Taiwan which have been sporadic yet highly volatile during the past two decades, exhibiting record-breaking magnitude in recent y...Objective: To ascertain the role of imported cases and serotypes on dengue outbreaks in Taiwan which have been sporadic yet highly volatile during the past two decades, exhibiting record-breaking magnitude in recent years. Methods: Confirmed case and serotype data from Taiwan Centers for Disease Control during 1998-2017 were fully examined, with fitting of weekly and daily case data of each city/county to a mathematical model to pinpoint the waves of cases and their locations. Moreover, we quantify the timing of turning point and transmission potential of each wave and determine its circulating serotype, to ascertain any pattern or connection between the variations in circulating serotypes and the magnitude/transmissibility of outbreak. Results: While the number of imported case increased steadily during past two decades, the yearly number of indigenous cases fluctuated wildly. Moreover, while yearly percentages of serotypes for imported cases remains steady, that of indigenous cases does not exhibit any clear pattern. There was at least one wave of reported cases somewhere in Taiwan every year from 1998 to 2015, except in 2016-2017. The effective reproduction number R for all waves in all locations ranged from 1.14 to 2.87, with the exception of two Tainan waves, in 2010(3.95) and 2015(6.84). Four major outbreaks of over 2000 cases reveal circulation of one dominant serotype. Conclusions: Correlation between imported cases and indigenous outbreak prove to be difficult to ascertain, even with the availability of serotype data. However, although there had been occasional co-circulation of serotypes in one location, and for some years with different serotypes circulating in different locations, all major outbreaks of over 2 000 cases during the past two decades are due to circulation of mainly a single serotype, perhaps indicating greater transmission potential with one dominating serotype.展开更多
Rapid identification and characterization of Listeria monocytogenes are required for the food industry, epidemiological studies, and disease prevention and control. However, typing procedures are labor-intensive and t...Rapid identification and characterization of Listeria monocytogenes are required for the food industry, epidemiological studies, and disease prevention and control. However, typing procedures are labor-intensive and time-consuming, and they require technical expertise, a panel of sera and reference culture strains or sophisticated and expensive equipment. To improve upon traditional diagnostic methods for L. monocytogenes we developed and evaluated an efficient procedure for the specific identification of L. monocytogenes and the major pathogenic serotypes of the species based on loop-mediated isothermal amplification (LAMP). Four individual reactions were designed using primers targeting any L. monocytogenes serotypes (LAMP-AS) and the 1/2a (LAMP-1/2a), 1/2b (LAMP-1/2b), and 4b (LAMP-4b) serotypes. The procedure distinguished L. monocytogenes from closely genetically related species and the targeted serotypes. Cross-reactivity with a few rare serotypes isolated from food or clinical samples did not impair the usefulness of the procedure. Thus, our approach constitutes a fast, easy and low-cost alternative for L. monocytogenes diagnosis and serotyping and may be useful for surveillance and epidemiological investigation programs.展开更多
Non-O157 STEC has been shown to have a diverse ecological distribution among food-animals. It has been associated with both outbreaks and individual cases of severe illness. This group of the organisms is now consider...Non-O157 STEC has been shown to have a diverse ecological distribution among food-animals. It has been associated with both outbreaks and individual cases of severe illness. This group of the organisms is now considered as a major contributor to human disease. The clinical description of the diseases caused by these organisms is reviewed. The host specificity of these pathogens is described and discussed. These organisms appear widespread among food animals like cattle and sheep, and can therefore affect a range of foods directly from the meat and excretions of these animals being used in farming practices. This article reviews the origins, diversity and pathogenesis of non-O157 STEC.展开更多
基金supported by a grant from Beijing Municipal Natural Science Foundation [L212011]National Institute for Communicable Disease Control and Prevention,Chinese Center for Disease Control and Prevention [131031102000210003&102393230020020000002]。
文摘Objective To establish and modify quantitative real-time polymerase chain reaction(qPCR)-based serotyping assays to distinguish 97 pneumococcal serotypes.Methods A database of capsular polysaccharide(cps)loci sequences was generated,covering 97 pneumococcal serotypes.Bioinformatics analyses were performed to identify the cps loci structure and target genes related to different pneumococcal serotypes with specific SNPs.A total of 27 novel qPCR serotyping assay primers and probes were established based on qPCR,while 27 recombinant plasmids containing serotype-specific DNA sequence fragments were constructed as reference target sequences to examine the specificity and sensitivity of the qPCR assay.A panel of pneumococcal reference strains was employed to evaluate the capability of pneumococcal serotyping.Results A total of 97 pneumococcal serotyping assays based on qPCR were established and modified,which included 64 serotypes previously reported as well as an additional 33 serotypes.Twenty-seven novel qPCR serotyping target sequences were implemented in the pneumococcal qPCR serotyping system.A total of 97 pneumococcal serotypes,which included 52 individual serotypes and 45 serotypes belonging to 20 serogroups,could not be identified as individual serotypes.The sensitivity of qPCR assays based on 27 target sequences was 1–100 copies/μL.The specificity of the qPCR assays was 100%,which were tested by a panel of 90 serotypes of the pneumococcal reference strains.Conclusion A total of 27 novel qPCR assays were established and modified to analyze 97pneumococcal serotypes.
基金Supported by Research Department of School of Medicine Shahid Beheshti University of Medical Sciences,No.17920,and accepted by the ethic committee,Code.IR.SBMU.MSP.REC.1398.349.
文摘BACKGROUND Extended-spectrumβ-lactamase(ESBL)-producing Escherichia coli(E.coli)are among the main pathogens in urinary tract infections(UTIs)among kidney transplant patients(KTPs).AIM To estimate the prevalence of ESBL-producing E.coli in KTPs and to evaluate the most prevalent serotypes and antibacterial susceptibility patterns of isolated bacteria in Tehran,Iran.METHODS A total of 60 clinical isolates of uropathogenic E.coli were collected from 3 kidney transplant centers from April to May 2019.Antimicrobial susceptibility testing was performed by the disk diffusion method as recommended by the Clinical Laboratory and Standards Institute.The serotyping of E.coli isolates was performed by the slide agglutination method.The presence of blaTEM,blaSHV,and bla CTX-M genes was evaluated by polymerase chain reaction.RESULTS The frequency of ESBL-producing E.coli in KTPs was found to be 33.4%.All of the 60 E.coli isolates were found to be susceptible to doripenem(100%)and ertapenem(100%).High resistance rates to ampicillin(86%),cefotaxime(80%),and cefazolin(77%)were also documented.The most frequent serotypes were serotype I(50%),serotype II(15%),serotype III(25%),and serotype VI(10%).The gene most frequently found was blaTEM(55%),followed by blaCTX-M(51%)and blaSHV(41%).CONCLUSION Molecular analysis showed that blaTEM was the most common ESBL-encoding gene.The high resistance toβ-lactams antibiotics(i.e.,ampicillin,cefotaxime,and cefazolin)found in E.coli from KTPs with UTIs remains a serious clinical challenge.Further efforts to control ESBL-producing E.coli should include the careful use of all antibiotics as well as barrier precautions to reduce spread.
文摘Bovine Respiratory Disease (BRD) causes a severe form of pneumonia in all age of cattle. This study was designed to investigate the distribution of capsular types, serotypes, and virulence-associated genes of the major bacterial pathogens from BRD outbreak samples in Ethiopia. In this study 166 samples were collected from clinically sick (<i>n</i> = 107) and pneumonic lung tissue (<i>n</i> = 59). Laboratory assay confirmed isolation of <i>M. haemolytica</i> 37 (22.29%), <i>P. multocida</i> 25 (15.06%), <i>B. trehalosi</i> 12 (7.23%), and <i>H. somni</i> 15 (9.04%). PCR assay of <i>P. multocida</i> capsular typing revealed 21 (84.0%) cap A (<i>hyaD-hyaC</i>) and 4 (16.0%) cap D (<i>dcbF</i>) strains. <i>M. haemolytica</i> serotypes belonged to A: 1, A: 2, and A: 6 from 26 (70.27%), 4 (10.81%), and 7 (18.92%) isolates, respectively. <i>P. multocida</i> biotyping showed isolation of A: 1, A: 2, and A: 3 from 3 (14.29%), 2 (9.52%), and 16 (76.19%) isolates, respectively. <i>M. haemolytica</i> harbored more than 60% <i>ssa</i> gene, and 90.91% <i>sodA</i> while <i>FbpA</i>, <i>TbpA</i>, and <i>lktC</i> genes were found in all isolates. Likewise, all <i>P. multocida</i> exhibited <i>toxA</i>, <i>FbpA</i>, <i>TbpA</i>, and <i>pmSLP</i> genes. The current finding showed that <i>M. haemolytica</i> serotype A: 1 is frequently associated with BRD followed by <i>P. multocida</i> biotype A: 3. These two isolates harbored diverse virulence-associated genes and presented the pathogenic potential of the current isolates. Thus, investigation of pathogenic strains of BRD, virulence genes distribution, and molecular epidemiology of the disease from wider areas of the country are essential. Hence, continuous outbreak surveillance and molecular approaches are indispensable in designing efficient prevention strategies.
基金supported by the National Natural Science Foundation of China(U22A20520)the Innovation Team Project of Modern Agricultural Industrial Technology System of Guangdong Province,China(2023KJ119)the Natural Science Foundation Program of Guangdong Province,China(2023A1515012206)。
文摘Streptococcus suis serotype 2(S.suis 2)is a zoonotic pathogen that clinically causes severe swine and human infections(such as meningitis,endocarditis,and septicemia).In order to cause widespread diseases in different organs,S.suis 2 must colonize the host,break the blood barrier,and cause exaggerated inflammation.In the last few years,most studies have focused on a single virulence factor and its influences on the host.Membrane vesicles(MVs)can be actively secreted into the extracellular environment contributing to bacteria-host interactions.Gram-negative bacteria-derived outer membrane vesicles(OMVs)were recently shown to activate host Caspase-11-mediated non-canonical inflammasome pathway via deliverance of OMV-bound lipopolysaccharide(LPS),causing host cell pyroptosis.However,little is known about the effect of the MVs from S.suis 2(Gram-positive bacteria without LPS)on cell pyroptosis.Thus,we investigated the molecular mechanism by which S.suis 2 MVs participate in endothelial cell pyroptosis.In this study,we used proteomics,electron scanning microscopy,fluorescence microscope,Western blotting,and bioassays,to investigate the MVs secreted by S.suis 2.First,we demonstrated that S.suis 2 secreted MVs with an average diameter of 72.04 nm,and 200 proteins in MVs were identified.Then,we showed that MVs were transported to cells via mainly dynamin-dependent endocytosis.The S.suis 2 MVs activated NLRP3/Caspase-1/GSDMD canonical inflammasome signaling pathway,resulting in cell pyroptosis,but it did not activate the Caspase-4/-5 pathway.More importantly,endothelial cells produce large amounts of reactive oxygen species(ROS)and lost their mitochondrial membrane potential under induction by S.suis 2 MVs.The results in this study suggest for the first time that MVs from S.suis 2 were internalized by endothelial cells via mainly dynamin-dependent endocytosis and might promote NLRP3/Caspase-1/GSDMD pathway by mitochondrial damage,which produced mtDNA and ROS under induction,leading to the pyroptosis of endothelial cells.
基金supported by the Ministry of Higher Education under the Fundamental Research Grant Scheme(FRGS/1/2021/SKK0/UPM/02/8)the Universiti Putra Malaysia Research University Grant Scheme(GP/IPS/2021/9702000).
文摘Objective:To determine the distribution,phenotypic and genetic background of extended spectrumβ-lactamases(ESBL)-producing Klebsiella(K.)pneumoniae clinical isolates associated with K1 and K2 serotypes in two selected hospitals in Malaysia.Methods:A total of 192 K.pneumoniae isolates were collected and subjected to antibiotic susceptibility,hypermucoviscosity test and multiplex PCR to detect the presence of K1-and K2-serotype associated genes.Multilocus sequence typing(MLST)was performed on ESBL-producing K.pneumoniae isolates presented with K1 and K2 serotypes,followed by phylogenetic analysis.Results:A total of 87 out of 192(45.3%)of the K.pneumoniae isolates collected were ESBL producers.However,only 8.3%(16/192)and 10.9%(21/192)of the total isolates were detected to carry K1-and K2-serotype associated genes,respectively.Statistical analysis showed that K1 and K2 capsular serotypes were not significantly associated with ESBL phenotype(P=0.196).However,they were significantly associated with hypervirulent,as demonstrated by the positive string test(P<0.001).MLST analysis revealed that ST23 as the predominant sequence type(ST)in the K1 serotype,while the ST in the K2 serotype is more diverse.Conclusions:Although the occurrence of ESBL-producing isolates among the hypervirulent strains was low,their coexistence warrants the need for continuous surveillance.MLST showed that these isolates were genetically heterogeneous.
基金supported in part by the grant from National Natural Science Foundation of China(82171818,81703048,82041019,and 82101919)the grant from Defense Industrial Technology Development Program of China(JCKY2020802B001)Beijing Municipal Science and Technology Commission(Z201100005420024)。
文摘Recombinant adenovirus serotype 5(Ad5)vector has been widely applied in vaccine development targeting infectious diseases,such as Ebola virus disease and coronavirus disease 2019(COVID-19).However,the high prevalence of preexisting anti-vector immunity compromises the immunogenicity of Ad5-based vaccines.Thus,there is a substantial unmet need to minimize preexisting immunity while improving the insert-induced immunity of Ad5 vectors.Herein,we address this need by utilizing biocompatible nanoparticles to modulate Ad5–host interactions.We show that positively charged human serum albumin nanoparticles((+)HSAnp),which are capable of forming a complex with Ad5,significantly increase the transgene expression of Ad5 in both coxsackievirus–adenovirus receptor-positive and-negative cells.Furthermore,in charge-and dose-dependent manners,Ad5/(+)HSAnp complexes achieve robust(up to227-fold higher)and long-term(up to 60 days)transgene expression in the lungs of mice following intranasal instillation.Importantly,in the presence of preexisting anti-Ad5 immunity,complexed Ad5-based Ebola and COVID-19 vaccines significantly enhance antigen-specific humoral response and mucosal immunity.These findings suggest that viral aggregation and charge modification could be leveraged to engineer enhanced viral vectors for vaccines and gene therapies.
基金funded by the Ministry of Higher Education under Fundamental Research Grant Scheme(FRGS/1/2023/WAB04/UPM/01/4).
文摘and pili genes are also investigated.Methods:This multicentre,prospective,observational study is conducted in seven major tertiary hospitals in Malaysia among non-pregnant adults.Simultaneously,a retrospective study is conducted in the selected hospitals with similar approaches.GBS isolates are subjected to phenotyping,serotyping by multiplex PCR,antimicrobial susceptibility testing and PCR-detection of GBS virulence and pilus genes.Seven housekeeping genes are amplified and sequenced for multi-locus sequence typing.Discussion:Findings from the study may contribute to the management of clinical practice to diagnose and prevent GBS related diseases in a timely manner.Prudent use of antibiotics is encouraged by monitoring antimicrobial resistance.
文摘Background: The main objective of this study is to describe the rate of the different serotypes of HPV in cervical cytologies and biopsies in three different periods: 2002-2006 (prior to the implementation of the vaccination programs in Spain), 2009-2011 (shortly after this implementation) and 2020 (almost 15 years after introduction of the vaccine) at a single hospital. Methods: This is an observational, descriptive, retrospective study based on the review of the results of the determination of the HPV serotype using the commercial kit (Genomica<sup>®</sup>;PharmaMar LTD) in cervical liquid-based cytologies and biopsies at a single large tertiary hospital, Hospital Clínico San Carlos, in Madrid, Spain. We have collected the data from three different time periods: 2002-2006;2009-2011, and 2020 to try to understand the potential changes associated with the use of the vaccine. Results: In these time periods we have reviewed the data from 1420 women. In the three periods the most frequent serotype was HPV 16, followed by HPV 18 or a combination of both. The most frequent low risk serotype was HPV 6 followed by the combination of HPV 6 and 11. It has been verified in our study that the prevalence of the category “others”, constituted by the three risk groups, has undergone a progressive increase, beginning with an infection rate of 65.43% in 2002-2006 to finally rise up to 90.92% in the year 2020. Conclusions: Our study reveals an increase in the number of infections by the HPV serotypes that are not included in the tetravalent vaccine.
文摘Background: The main objective of this study is to analyse the change in the type of lesions developed by HPV-infected patients after the introduction of the vaccine in three different periods;2002-2006 (years previous to the implementation of the vaccine in Spain), 2009-2011 (shortly after the vaccination) and 2020-2021 (years where the vaccine was well established) at a single hospital. Methods: This is an observational, descriptive, retrospective study based on the review of the results of the biopsies of patients with HPV lesions at a single large tertiary hospital, Hospital Clínico San Carlos, in Madrid, Spain. We have collected the data from three different time periods: 2002-2006, 2009-2011, 2020-2021 to try to understand the potential changes in these lesions after vaccine introduction. Results: In this time we have reviewed the data from 946 women. In these three periods, a decreasing trend in the rate of squamous cell carcinoma was noted, the rate of adenocarcinoma remains stable, and the rate of cervical intraepithelial neoplasia grades 2 - 3 (CIN 2-3) lesions shows an increasing trend. We have also found a change in the mean ages of the patients with these lesions, as this increased in the three lesions caused by HPV after the implementation of the vaccine. Our study indicates that the identification of other high risk serotypes, apart from 16 and 18, as well as those with indeterminate risk, has undergone a progressive increase, increasing from 24.24% and 14.11% respectively in 2002-2006 to 40.42% and 28.34% in 2020-2021. Conclusion: Our study confirms the effectiveness of the vaccines developed so far, against the HPV serotypes they contain. This is demonstrated by the evidence, in our population, of a decrease in the incidence of squamous cell carcinoma in uterine cervix. In parallel, an increase in the mean age of diagnosis has been verified, for both squamous cell carcinoma and its CIN 2-3 precursor lesions, as well as a change in the infective trend of HPV serotypes that are not included in the current vaccines.
文摘Nutritional value of vegetables and high prices of meat and meat originated food compel common people to consume plant originated food particularly salad vegetables. Microbial population of vegetable surfaces contains a large number of pathogenic bacteria including members of Enterobactereace like Escherichia coli (E. coli). A survey was conducted in three major markets of Rawalpindi, Pakistan. Tomato, lettuce, cabbage and cucumber samples were collected from three shops of each market. Each vegetable was analysed as unwashed and washed for total coliforms, faecal coliforms and E. coli by FAO (Food Quality Manual). About two hundred and fifty E. coli isolates were preserved, serotyped for presence of O157 serotype. Total coliforms, faecal coliforms and E. coli count exceeded the permissible limits in most samples. The highest Total coliforms were associated with cabbage (3.78 log10 cfu/g). Cucumber was the least contaminated by Total coliforms (2.15 log10 cfu/g). E. coli was detected in tomato, lettuce, cucumber and cabbage. Washed samples showed reduced bacterial population. Seventy six isolates of E. coli were biochemically characterized and serotyped for O157 antigen. A majority of strains could not be identified by serotyping. These findings conclude with high potentially pathogenic microbial load on salad vegetables and urge for preventive action on priority basis.
文摘Campylobacter is one of the most common bacterial enteropathogens of food borne origin in industrialized countries with C. jejuni being the most common species followed by C. coli. The prevalence of Campylobacters in and around Chandigarh, India was studied by phenotypic and genotypic methods. Fecal samples from 1145 diarrheal patients and 102 healthy subjects from hospital and community were cultured on Campylobacter media and identified by Gram stain, biochemical investigations and serotyping. Molecular identification of Campylobacter isolates was done using specific primers to unique regions of 16S rRNA, Campylobacter jejuni (hipO), Campylobacter coli (aspK), Campylobacter lari (glyA) and Campylobacter upsaliensis (lpxA) genes. Identification of specific genes to look for resistance to nalidixic acid, ciprofloxacin, tetracyclin and streptomycin was also done. Campylobacters were isolated from 2.6% of patients with diarrhea. Campylobacteriosis was more prevalent in children ≤5 years old and during summer season. The most frequent serotypes were S:27, B:2, Z5:52 and V:32. All the Campylobacters isolated by culture were confirmed genotypically by identification of 16S rRNA, hipO and aspK genes. Of the 30 isolates, 27 were C. jejuni and 3 were C. coli. No C. lari or C. upsaliensis were detected. Antibiotic resistance was 40% for nalidixic acid, 23.3% for ciprofloxacin, 50% for tetracyclin and 20% for streptomycin. Campylobacter prevalence is low in the region with C. jejuni being the most common species. A high degree of resistance was found for nalidixic acid and tetracyclin but moderate for ciprofloxacin and streptomycin.
文摘Campylobacter is one of the most common food-borne bacterial enteropathogens. We planned to investigate the prevalence and antibiotic resistogram of Campylobacter in poultry in and around Chandigarh. Poultry samples (n = 127) were obtained from slaughter houses/retail outlets and cultured microaerophilically on Campylobacter media. The isolates were identified phenotypically and by molecular investigation. Identification of specific genes to look for resistance to nalidixic acid, ciprofloxacin, tetracyclin and streptomycin was also done. Campylobacter was isolated from 57/127 (44.9%) of the samples. The most frequent serotypes identified were B: 2, S: 27, Z5: 52 and Z7: 57. All culture isolates (100%) were reconfirmed as Campylobacter by 16S rRNA polymerase chain reaction. Molecular identification of isolates revealed the presence of C. jejuni in 45 (79.0%), C. coli in 1 (1.8%) and co-infection of C. coli and C. jejuni in 11 (19.3%). No C. lari and C. upsaliensis were detected. Antibiogram typing showed nalidixic acid resistance in 36.8%, ciprofloxacin resistance in 35.0% and 31.5% resistance for both streptomycin and tetracyclin. A high level of Campylobacter prevalence was found among the poultry with C. jejuni being the most commonly isolated species. Resistance to major antibiotics among Campylobacter isolates from poultry was also very high. The study of prevalence of Campylobacter in poultry and its resistance to major antibiotics will help to plan risk burden strategies throughout the food chain.
文摘AIM: To discover the relationship between the genotype and antigen serotype of flagellin C among Salmonella strains.METHODS: Fragment of Salmonella flagellin C in plasmid pLS408 was cloned, sequenced and compared with the corresponding sequence in other strains. Salmonella strains including two typhi strains, one paratyphoid strain, one enteritidis and one typhimurium strain were isolated from outpatients. Genome DNA was purified respectively from these clinical isolstes, then the corresponding flagellin C fragment was amplified by polymerase chain reaction, and the amplification products were analyzed by agarose gel electrophoreeis.RESULTS: The cloned fragment includes 582 nucleotides encoding the variable region and partial conservative region of Salmonella flagellin C in plasmid pLS408. With comparison to the corresponding sequences reported previously, there is only a little difference from other strains with the same flagellar serotype in both nucleotide and amino acid level. Specific PCR products were amplified in Salmonella strains with flagellar eerotype H-1-d including S. Muenchen, typhi and typhimurium, but not in S.paratyphoid C or S. Enteritidis strains.CONCLUSION: In this experiment, the specificity of nucleotide sequence could be found in flagellin C central variable regions as it exists in flagellar serotypes in Salmonella. It may be helpful to developing a rapid,sensitive, accurate and PCR-based method to detect Salmonella strains with serotype H-1-d.
基金supported by Institute for Medical Research Operational Grant(Vol:040300/OS27403)
文摘Objective:To identify the circulating serotypes of human echovinis in Malaysia from 2002 in 2013.Methods:A toial of 31 retrospective samples from non-polio acute flacid paralysis,hand-food-and-mouth disease,viral meningitis and enterovirus cases were subjected to amplification of partial VPI gene by RT-PCR.Results:Sequencing and phylogeneiic analysis of the partial sequences identified presence of human echovinis and human coxsackie viruses.It was found that echovinis 11 was the commonly circulating serotype followed by echovinis6.echovinis 7.echovinis 3.echovinis 9.echovinis 30 and echovinis I in decreasing order.Additionally two types of human coxsackie virus isolates were detected which were coxsackie A24 and B3.Condusions:From the findings,there is a possibility that echovinis 11 is the predominant serotype among Malaysian patients with echovinis infection.However,a larger sample size will yield a more confident result to support this evidence.____________________
基金supported by the National Key Research and Development Program of China (2016YFD0500801)
文摘Hepatitis-hydropericardium syndrome(HHS)is an infectious disease caused by fowl adenovirus serotype 4(FAdV-4).Several structural and non-structural proteins of FAdV-4 have been expressed in Escherichia coli and baculovirus expression system to develop candidate subunit vaccines.However,the protective efficiency of baculovirus-expressed penton base protein has not been assessed.In this study,two recombinant capsid proteins,penton base and fiber-2,were constructed.And then,penton base and fiber-2 were administrated alone or together to specific pathogen-free(SPF)chickens at 14 days of life and boosted at 28 days of life.At 42 days of life,the immunized groups and the control group were challenged with FAdV-4 virulent strain.Results show that inoculating penton base or penton base+fiber-2 provided 100%protection to the chickens.All groups vaccinated with the recombinant protein produced detectable antibodies and showed no apparent lesions.Thus,baculovirus-expressed penton base protein is a promising candidate subunit vaccine.
基金Supported by the Hubei Province Health and Family Planning A Scientific Research Project,No.WJ2017M220the Wuhan Health Bureau Scientific Research Fund,No.WX19C11+2 种基金the Joint Precision Medical Research Fund From Taihe Hospital,No.2016JZ10the Shiyan COVID-19 Pilot Emergency Scientific Research Project,No.20Y19the Wuhan Children's Hospital Research Project,No.2017FE007.
文摘BACKGROUND Hand,foot,and mouth disease(HFMD)has become one of the most common infectious diseases in China.Before 2016,the primary causal serotypes were enterovirus A71(EV-A71)and coxsackievirus A16(CV-A16).Following the introduction of EV-A71 vaccines in China since 2016,the situation could change.CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China.However,the epidemiological characteristics of central China remain unknown.AIM To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City,central China,in recent years.METHODS The epidemiological,clinical,and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed.196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020.To detect and genotype enteroviruses,real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used.In Shiyan,168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes.Based on the logistic regression model,the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.RESULTS From 2016 to 2020,35840 HFMD cases were reported in Shiyan.The number of cases decreased by 48.4%from 2016 to 2017.Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year,respectively.In 2020,a decrease of about 85.5%was reported when compared to 2019.The most common serotypes shifted from EV-A71 and CV-A16(about 60%-80%in 2016 and 2018)to others(more than 80.0%in 2017,2019,and 2020).EV-A71 lost its dominance in 2017 in Shiyan.Among 196 confirmed HFMD cases,85.7%tested positive for enterovirus,with CV-A6 being the most common serotype(121/168,72.0%).The positive rates for CV-A16 and CVA10 were 4.8%and 3.0%,respectively.There was no EV-A71 discovered.Infection with CV-A6 was linked to fever,myocardial damage,increased creatine kinase MB isoenzyme,and lactate dehydrogenase levels.CONCLUSION CV-A6 was the most common enterovirus serotype in Shiyan City,replacing EV-A71 and CV-A16 as the HFMD pathogen.Developing vaccines against CV-A6 or multiple pathogens,as well as rising CV-A6 surveillance,will help prevent HFMD in central China.
基金supported by the National Key R&D Program of China (2017YFD0500203)the National Transgenic Major Program of China (2014ZX0800946B)+3 种基金the National NaturalScience Foundation of China (31672574)the Special Fund for Agro-scientific Research in the Public Interest, China (201403054)the Jiangsu Agricultural Science and Technology Innovation Fund, China ([CX (16) 1028])the Priority Academic Program Development of Jiangsu Higher Education Institutions, China (PAPD)
文摘Streptococcus suis is one of the major pathogens of swine streptococcosis. Among them, the strongest virulence and highest rate of clinical isolation serotype is S. suis serotype 2(SS2). Moreover, SS2 is also an important zoonosis pathogen, which caused severe public health issues in China. It has been reported that SS2 has several virulence factors, including muramidase released protein, extracellular factors, capsule, fibronectin-binding protein, enolase, hemolysin, small RNA, biofilm, two-component regulatory systems, STK/STP, etc., whose functions involved in adhesion, anti-phagocytosis, inflammatory pathway activation, invasion, etc. Actually, SS2 has developed a variety of ways to escape from host immune system during evolution. In particularly, capsule could resist phagocytosis through inhibiting sphingosine dependent immune cell recognition, which plays an important role in escaping host inflammation response; moreover, superoxide dismutase encoding by sod A enables SS2 escaping reactive oxygen species(ROS) in host immune cells; besides, binding complement factor h with Fhb could suppress the activation of complement alternative pathway and bactericidal effect. And SS2 could also hinder the formation of neutrophil extracellular traps(NETs) to avoid trapping by swine neutrophils, while host immune globulin could be degraded by Ig A1 hydrolase and Ig M protease. In addition, SS2 could escape host immune defense with the help of multiple transcriptional factors and micro-RNA. So far, the pathogenesis of meningitis, arthritis caused by SS2 infection, is still unclear, and the virulence regulatory mechanism of phosphorylation, micro-RNA need to be further clarified. Importantly, the study of interaction mechanism of pathogen and host contribute to further demonstration the pathogenesis of SS2.
基金supported by funding from grants from Taiwan Ministry of Science and Technology(MOST 103-2314-B-039-010-MY3)China Medical UniversityTaiwan(CMU106-S-02)
文摘Objective: To ascertain the role of imported cases and serotypes on dengue outbreaks in Taiwan which have been sporadic yet highly volatile during the past two decades, exhibiting record-breaking magnitude in recent years. Methods: Confirmed case and serotype data from Taiwan Centers for Disease Control during 1998-2017 were fully examined, with fitting of weekly and daily case data of each city/county to a mathematical model to pinpoint the waves of cases and their locations. Moreover, we quantify the timing of turning point and transmission potential of each wave and determine its circulating serotype, to ascertain any pattern or connection between the variations in circulating serotypes and the magnitude/transmissibility of outbreak. Results: While the number of imported case increased steadily during past two decades, the yearly number of indigenous cases fluctuated wildly. Moreover, while yearly percentages of serotypes for imported cases remains steady, that of indigenous cases does not exhibit any clear pattern. There was at least one wave of reported cases somewhere in Taiwan every year from 1998 to 2015, except in 2016-2017. The effective reproduction number R for all waves in all locations ranged from 1.14 to 2.87, with the exception of two Tainan waves, in 2010(3.95) and 2015(6.84). Four major outbreaks of over 2000 cases reveal circulation of one dominant serotype. Conclusions: Correlation between imported cases and indigenous outbreak prove to be difficult to ascertain, even with the availability of serotype data. However, although there had been occasional co-circulation of serotypes in one location, and for some years with different serotypes circulating in different locations, all major outbreaks of over 2 000 cases during the past two decades are due to circulation of mainly a single serotype, perhaps indicating greater transmission potential with one dominating serotype.
文摘Rapid identification and characterization of Listeria monocytogenes are required for the food industry, epidemiological studies, and disease prevention and control. However, typing procedures are labor-intensive and time-consuming, and they require technical expertise, a panel of sera and reference culture strains or sophisticated and expensive equipment. To improve upon traditional diagnostic methods for L. monocytogenes we developed and evaluated an efficient procedure for the specific identification of L. monocytogenes and the major pathogenic serotypes of the species based on loop-mediated isothermal amplification (LAMP). Four individual reactions were designed using primers targeting any L. monocytogenes serotypes (LAMP-AS) and the 1/2a (LAMP-1/2a), 1/2b (LAMP-1/2b), and 4b (LAMP-4b) serotypes. The procedure distinguished L. monocytogenes from closely genetically related species and the targeted serotypes. Cross-reactivity with a few rare serotypes isolated from food or clinical samples did not impair the usefulness of the procedure. Thus, our approach constitutes a fast, easy and low-cost alternative for L. monocytogenes diagnosis and serotyping and may be useful for surveillance and epidemiological investigation programs.
文摘Non-O157 STEC has been shown to have a diverse ecological distribution among food-animals. It has been associated with both outbreaks and individual cases of severe illness. This group of the organisms is now considered as a major contributor to human disease. The clinical description of the diseases caused by these organisms is reviewed. The host specificity of these pathogens is described and discussed. These organisms appear widespread among food animals like cattle and sheep, and can therefore affect a range of foods directly from the meat and excretions of these animals being used in farming practices. This article reviews the origins, diversity and pathogenesis of non-O157 STEC.
