Serological Typing Research Articles

Experimental ecological research on the relationships of pathogenic microorganisms with algae

Aim. The ecological relationships between Leptospira interrogans spirochetes and Chlamydomonas proteus algae and the response explicitness of individual serological types of leptospires to the allelopathic effect of algae were to be investigated during the experiment. Methods. C. proteus algae monocultures were cultivated on the Fitzgerald’s medium in the Zehnder and Gorham’s modifi cation. Sterile fi ltrates of their cultures were diluted with the nutrient medium in the ratio of 1 : 10, 1 : 100, 1 : 1,000, 1 : 10,000. Leptospires were cultivated on the Terskih and Korthof’s medium with the addition of 10 % inactivated sheep blood serum. The test samples contained diluted culture fi ltrates of algae and leptospires. The control samples were the environment for algae and leptospires cultivation. Results. In the samples with the 1 : 10 – 1 : 100 dilution of algae fi ltrates, the content of leptospires in the test samples was signifi cantly lower than in the control samples, indicating their moderate and weak inhibition. There were no statistically signifi cant differences between spirochete culture densities in the test and control samples with the dilutions of 1 : 1,000–1 : 10,000 algae fi ltrates. Conclusions. In the experiment, a topical type of ecological interspecies relationships is formed between L. interrogans and green species of C. proteus algae, which is realized through the release of biologically active substances into the habitat by C. proteus. According to the increasing sensitivity to the allelopathic effect of C. proteus, serological types of leptospires formed a row: Tarassovi, Icterohaemorrhagiae, Pomona, Grippotyphosa, Australis, Sejroe, Canicola, Hebdomadis.

Molecular Mechanism and family research of a pedigree with B(A).06 subtype

To explore the serological and genotypic characteristics of a pedigree with B(A).06 subtype. Serological methods was used to identify the ABO phenotypes. Exons 6 and 7 of the ABO gene and flanking regions were subjected to direct sequencing and TA clonal sequencing in order to determine the genotype of individuals with inconsistent results for forward and reverse serological typing. Among 12 individuals from 4 generations, 5 were identified with a AwB phenotype, along with a c.803C>G mutation in exon 7 of the B allele, which was named as B(A).06. The B(A).06/O.01.01 phenotype may be easily missed due to its weak anti-A antibody in the serum upon initial serological test. A B(A).06 subtype family was identified. The serological phenotype of individuals carrying the B(A).06 allele may be affected by the opposite DNA strand.

Serotyping of Toxoplasma gondii Infection Using Peptide Membrane Arrays

The intracellular parasite Toxoplasma gondii can cause chronic infections in most warm-blooded animals, including humans. In the USA, strains belonging to four different Toxoplasma clonal lineages (types 1, 2, 3, and 12) are commonly isolated, whereas strains not belonging to these lineages are predominant in other continents such as South America. Strain type plays a pivotal role in determining the severity of Toxoplasma infection. Therefore, it is epidemiologically relevant to develop a non-invasive and inexpensive method for determining the strain type in Toxoplasma infections and to correlate the genotype with disease outcome. Serological typing is based on the fact that many host antibodies are raised against immunodominant parasite proteins that are highly polymorphic between strains. However, current serological assays can only reliably distinguish type 2 from non-type 2 infections. To improve these assays, mouse, rabbit, and human infection serum were reacted against 950 peptides from 62 different polymorphic Toxoplasma proteins by using cellulose membrane peptide arrays. This allowed us to identify the most antigenic peptides and to pinpoint the most relevant polymorphisms that determine strain specificity. Our results confirm the utility of previously described peptides and identify novel peptides that improve and increase the specificity of the assay. In addition, a large number of novel proteins showed potential to be used for Toxoplasma diagnosis. Among these, peptides derived from several rhoptry, dense granule, and surface proteins represented promising candidates that may be used in future experiments to improve Toxoplasma serotyping. Moreover, a redesigned version of the published GRA7 typing peptide performed better and specifically distinguished type 3 from non-type 3 infections in sera from mice, rabbits, and humans.

Analysis of nine death cases with severe dengue fever

Objective To analyze the clinical features of death cases of dengue fever and the causes of their deaths. Methods The clinical data and death reports of nine death cases of dengue fever in Guangdong Province from June 23, 2014 to September 10, 2019 were retrospectively analyzed. All of nine cases were positive for serum dengue virus RNA as confirmed by reverse transcription polymerase chain reaction, and some of the virus strains were serotyped. Results The median age of the nine patients was 57.5 (range: 18-80) years. Among them, six patients were females; eight patients were local cases and one was imported case; all of nine cases occurred in September and October. The median time from onset to visit hospital and diagnosis was three and four days, respectively. Three of the nine patients had underlying diseases. All of nine cases had fever, including three with double-peak fever. Eight of the cases had three or more severe dengue fever warning indexes before admission. Three cases had severe bleeding upon admission, one case had shock, and six cases had organ failure. Three cases underwent invasive examination, including arterial puncture catheterization, endoscopic titanium clip hemostasis, and percutaneous transluminal coronary angiography. Two cases developed malignant arrhythmia and one had massive hemorrhage of subcutaneous soft tissue after operation. The death cases included four cases of cardiogenic shock and fatal arrhythmia, three cases of encephalitis and encephalopathy, one case of refractory shock, and one case of acute liver failure. Among the six cases that underwent serological typing, four were identified as dengue virus type 1 (DEN-1) and two were DEN-2. Conclusions Severe organ failure is the major cause of dengue fever-related death, especially fulminant myocarditis, and DEN-1 is most common. Early diagnosis and treatment, and avoidance of invasive procedures can effectively reduce the mortality rate of the severe dengue fever patients. Key words: Severe dengue; Clinical features; Cause analysis

Frequency of Mia (MNS7) and Classification of Mia-Positive Hybrid Glycophorins in an Australian Blood Donor Population

Background: MNS blood group system genes GYPA and GYPB share a high degree of sequence homology and gene structure. Homologous exchanges between GYPA and GYPB form hybrid genes encoding hybrid glycophorins GP(A-B-A) and GP(B-A-B). Over 20 hybrid glycophorins have been characterised. Each has a distinct phenotype defined by the profile of antigens expressed including Mi^a. Seven hybrid glycophorins carry Mi^a and have been reported in Caucasian and Asian population groups. In Australia, the population is diverse; however, the prevalence of hybrid glycophorins in the population has never been determined. The aims of this study were to determine the frequency of Mi^a and to classify Mi^a-positive hybrid glycophorins in an Australian blood donor population. Method: Blood samples from 5,098 Australian blood donors were randomly selected and screened for Mi^a using anti-Mi^a monoclonal antibody (CBC-172) by standard haemagglutination technique. Mi^a-positive red blood cells (RBCs) were further characterised using a panel of phenotyping reagents. Genotyping by high-resolution melting analysis and DNA sequencing were used to confirm serology. Result: RBCs from 11/5,098 samples were Mi^a-positive, representing a frequency of 0.22%. Serological and molecular typing identified four types of Mi^a-positive hybrid glycophorins: GP.Hut (n = 2), GP.Vw (n = 3), GP.Mur (n = 5), and 1 GP.Bun (n = 1). GP.Mur was the most common. Conclusion: This is the first comprehensive study on the frequency of Mi^a and types of hybrid glycophorins present in an Australian blood donor population. The demographics of Australia are diverse and ever-changing. Knowing the blood group profile in a population is essential to manage transfusion needs.

Serological and molecular typing in platelet alloantibody investigations

Alloimmunization against platelet antigens causes complications in transfusion settings as platelet transfusion refractoriness and post‐transfusion purpura, as well as in pregnancy, causing fetal/neonatal alloimmune thrombocytopenia. Strategies for the laboratory investigations depend on a repertoire of serological and molecular assays and are often dependent on timing and objective. Technical improvements have led to a number of sophisticated methods for alloantigen typing and alloantibody identifications during the last decade; however, some traditional methods are still beneficial. The laboratory investigations should ensure that the causative antibody specificities are identified as soon as possible to support the correct diagnosis and guide the selection of compatible platelets if needed.

Evaluating novel effective primers to amplify heterozygous alleles of second, third and fourth exons of HLA-A; -B; -C; -DRB1 and -DQB1 loci using sequencing-based typing

Human leukocyte antigen (HLA) typing is one of the most crucial steps that determines the success of an organ transplant. However, HLA typing is a challenging task due to the diversity of HLA alleles, which is caused by high polymorphism of the region and high number of guanine and cytosine bases that limits the degree of amplification. Low resolution serology typing currently employed in Sri Lanka may fail to identify subtle differences in certain alleles, which may affect the long-term survival of the organ recipient. Therefore, a low cost, high-resolution DNA-based typing method for the HLA loci of Sri Lankans was developed based on polymerase chain reaction (PCR) amplification followed by Sanger sequencing, which is considered to be the gold standard for HLA typing. With minimised PCR bias and equal chances of amplifying all the alleles curated so far, a novel set of primers were designed to amplify the second and third exons of alleles in group specific PCR. To increase the resolution of alleles further, the fourth exon was also amplified using novel primers designed in this study and primers reported in the literature. Touchdown PCR and hot-start PCR were used to optimise PCR conditions so that non-specific amplifications are minimal. SBTengine® (version 3.12.0.2724) software was used in assigning the sequence chromatogram to the allele sequence. Seventeen new primers were designed in this study to ensure the amplification and identification of both alleles in heterozygous individuals that were previously unable to be identified using primers reported in the literature.

Anemias hemolíticas autoinmunes: estudio retrospectivo de 93 pacientes

IntroductionAutoimmune haemolytic anaemia (AIHA) is an infrequent and heterogeneous disease in its pathophysiology and clinical behaviour, therefore it is generally managed empirically. Patients and methodsWe conducted an observational, retrospective and multicentre study of 93 patients diagnosed with AHAI in 9 Spanish hospitals between 1987 and 2017, with a median follow-up of 28 months. ResultsMedian age of 67 years; 85% AHAI for hot antibodies and 64% primary AHAI. The lowest haemoglobin values at diagnosis related to patients under 45 years of age and serological type IgG+C. Of the patients, 92% received first line treatment, 54% second line, and 27% third line. The warm AHAI were treated in first line with steroids, with overall responses of 83% and complete of 58%. Rituximab in monotherapy or in association with steroids was administered to 34 patients with overall responses close to 100% (complete responses 40-60%), relegating splenectomy to the third line. The immunosuppressive treatment was administered in patients with autoimmune diseases or in corticoid-dependent patients. DiscussionWe found high rates of response to steroids, with very prolonged treatments that cause side effects and corticoid dependence in a third of patients. The combination of steroids with rituximab in the first line, could be indicated in patients with low levels of haemoglobin and serological type IgG+C. The high relapse rates make necessary the development of randomised studies with new drugs or the combination with existing ones, which allow longer response times and with fewer side effects.

Hygienic profile of some ready to eat meat product sandwiches sold in Benha city, Qalubiya Governorate, Egypt

Ready-to-eat (RTE) meat product sandwiches have become one of the most important sources of nutrition, especially with changing consumer’s dietary and social habits; unfortunately, it may be loaded with many microorganisms especially accidental post-cooking cross-contamination; therefore, the study aimed to investigate the bacteriological quality of 120 ready to eat meat product sandwiches (beef kofta, bovine liver, fish fillet, and chicken nuggets), 30 of each, which were collected randomly from restaurants and street vendors located in Benha city, Qalubiya Governorate, Egypt. Results revealed that kofta samples were the most contaminated samples where mean values of aerobic plate count (APC) and coliforms were 9.6x106, and 1.9x102 CFUg, respectively; followed by chicken nuggets, fish fillet, and bovine liver samples; furthermore, E. coli and salmonellae of different serological types were detected in 5.8%, and 2.5% of examined samples, respectively. Obtained results indicated that RTE meat based sandwiches may pose a risk to consumer’s health in the absence of food safety knowledge and hygiene application; strict hygienic measures and authority inspection is strongly recommended.

Heterogeneity of antigen specificity between HLA-A*02:01 and other frequent Chinese HLA-A2 subtypes detected by a modified autologous lymphocyte-monocyte coculture

HLA-A2 is the most common serological HLA type among all ethnic groups. Through advances in DNA typing, more than 800 subtypes of HLA-A2 have been identified, and the existence of heterogeneity of antigen specificity among the HLA-A2 subtypes has been suggested by retrospective analyses of allogeneic transplantation patients and by studies of antigen amino acid structure. However, prior to this study, the antigenicity of a given subtype or the mismatch extent between two given subtypes could not be studied in vitro. Here, we used a modified autologous lymphocyte-monocyte coculture method to reveal heterogeneity of antigen specificity among HLA-A2 subtypes. The coculture was set up with HLA-A2 (non-A*02:01) lymphocytes and monocytes, and the monocytes were coated with an HLA-A*02:01/IgG1-Fc fusion protein (dimer) by high-affinity binding of the IgG1-Fc to FcgRI. Lymphocyte proliferation following coculture indicated that HLA-A*02:01 showed antigenicity against the HLA-A2 (non-A*02:01) subtype. Among the most frequent HLA-A2 subtypes in the Chinese population (HLA-A*02:01, -A*02:03, -A*02:06 and -A*02:07), we identified significant -A*02:01 antigenicity for T cells from -A*02:03 or -A*02:06 but not -A*02:07 individuals. Our findings were consistent with retrospective studies of allograft patients with a limited number of involved subtypes, indicating that this modified coculture method provides a practical and reliable means to study the antigenicity of HLA allele subtypes in vitro.

Streptococcus agalactiae in pregnant women in Brazil: prevalence, serotypes, and antibiotic resistance.

Brazilian data for maternal GBS colonization shows different prevalence rates. This conflicting data may be related to the absence of an official recommendation from the Federal Brazilian Health Authorities describing guidelines and protocols to perform GBS screening in pregnant women, in both public and private clinics. In the present review, we evaluated published reports addressing the prevalence of GBS in different regions of the country, methods used, and, when available, information regarding antibiotic resistance and serological typing of clinical isolates. According to this review, GBS prevalence in pregnant women in Brazil ranged from 4.2 to 28.4%, in the last 10years. Serotype Ia was the most prevalent. The highest antibiotic resistance rates were found for tetarcycline, although its use to treat GBS infections is not common. Our results also show high resistance rates to clindamycin and erythromycin, which are commonly used as an alternative to penicillin in GBS infecctions. The increased antibiotic resistance, variations in serotype distribution, and high GBS prevalences need to be further investigated. Based on the present situation, recommendations regarding GBS surveillance in the country were raised and may improve our strategies for preventing neonatal infections.

Genetic Association between Swine Leukocyte Antigen Class II Haplotypes and Reproduction Traits in Microminipigs.

The effects of swine leukocyte antigen (SLA) molecules on numerous production and reproduction performance traits have been mainly reported as associations with specific SLA haplotypes that were assigned using serological typing methods. In this study, we intended to clarify the association between SLA class II genes and reproductive traits in a highly inbred population of 187 Microminipigs (MMP), that have eight different types of SLA class II haplotypes. In doing so, we compared the reproductive performances, such as fertility index, gestation period, litter size, and number of stillbirth among SLA class II low resolution haplotypes (Lrs) that were assigned by a polymerase chain reaction-sequence specific primers (PCR-SSP) typing method. Only low resolution haplotypes were used in this study because the eight SLA class II high-resolution haplotypes had been assigned to the 14 parents or the progenitors of the highly inbred MMP herd in a previous publication. The fertility index of dams with Lr-0.13 was significantly lower than that of dams with Lr-0.16, Lr-0.17, Lr-0.18, or Lr-0.37. Dams with Lr-0.23 had significantly smaller litter size at birth than those with Lr-0.17, Lr-0.18, or Lr-0.37. Furthermore, litter size at weaning of dams with Lr-0.23 was also significantly smaller than those dams with Lr-0.16, Lr-0.17, Lr-0.18, or Lr-0.37. The small litter size of dams with Lr-0.23 correlated with the smaller body sizes of these MMPs. These results suggest that SLA class II haplotypes are useful differential genetic markers for further haplotypic and epistatic studies of reproductive traits, selective breeding programs, and improvements in the production and reproduction performances of MMPs.

Serological Epidemiology of Foot-and-mouth Disease among Sedentary Mixed-species Herds in Adamawa Region, Cameroon

Foot-and-mouth disease (FMD) is an economically important viral disease of domestic animals and wildlife. High circulation occurs during outbreaks but little is known about the current transmission dynamics in sedentary cattle and sheep herds. To investigate on this, samples from cattle and sheep located in the Vina Division of the Adamawa region of Cameroon, during FMD outbreaks were collected. Non-Structural Protein (NSP) and antigen detecting/serotyping FMD ELISAs were used for sample screening. The NSP serological data of cattle was used to estimate transmission parameters in catalytic and reverse catalytic models. The Akaike’s Information Criteria (AIC) revealed the reverse catalytic model as the most parsimonious for the NSP serological data and was used to estimate the force of infection (FOI), the rate of waning immunity and to estimate historic periods of sustained transmission. Four serological types of FMD notably O, A, SAT 1 and SAT 2 were identified from cattle vesicular epithelia tissues. Seroprevalence findings revealed 65.14% and 15.71% FMDV antibodies in cattle and sheep respectively with highest prevalence in both populations occurring in Mbidjoro. The FOI (λ) in sedentary herds was constant; the rate of waning immunity (ω) was 0.32 meaning cattle are generally immune for 3.12 years post natural infection. The reproductive number (Rt) was 7.33, meaning approximately 87% of cattle always need to be effectively immunized to prevent outbreaks. Therefore, FMD circulates in sedentary cattle and sheep populations in the study area with four serological types detected in cattle.

Comparison of serology and molecular detection of common red cell antigens in multitransfused thalassemia major and sickle cell disease patients

BackgroundSerological testing for extended RHCcEe, Kell, Kidd and Duffy blood grouping from multitransfused patients may not give correct blood grouping of the recipient. Hence molecular testing for these blood groups was compared with serological groups in a cohort of multitransfused thalassemia mjor and sickle cell anaemia patients. ObjectiveMolecular genotyping of antigens of Rh (D, C, c, E, e), Kell (K, k), Duffy (Fya, Fyb) and Kidd (Jka, Jkb) blood group antigens by PCR and PCR-RFLP methods and comparison of predicted genotypes with their serological phenotypes. Materials and methodsA cohort of multitransfused thalassemia and sickle cell anemia patient were serologically and molecularly tested for RHCc, RHEe, K, k Fya, Fyb, Jka and Jkb antigens and compared. Serological testing was done by tube agglutination and molecular testing was done either by allele specific PCR or by RFLP technique just before next transfusion. ResultsIn more than 80% of the cases recipient’s molecular testing blood groups were at variance with serologically tested blood groups (p < 0.0001). Mixed field reactions in serological typing were common. In sickle cell anemia patients no discrepancy was found. Molecular technique results were checked by Sanger’s sequencing. DiscussionExtended phenotyping in multitransfused thalassemia patients by serological technique often donot detect the exact red cell phenotype of the recipient and molecular techniques for such grouping is preferable, especially in multitransfused thalassemia patients where red cells from previous transfusions continues to be present in significant numbers whenever the testing is done.

Discrepancies between red cell phenotyping and genotyping in daily immunohematology laboratory practice

False-positive and false-negative reactions exist for serological and molecular antigen typing methods. If the predicted phenotype is inconsistent with the patient`s known antibodies or serological phenotype, the discrepancy must be investigated. False-negative and false-positive results are clinically problematic in blood donors and patients. In this study, we investigated discrepant results between serology and molecular testing in patients and blood donors that occurred in daily molecular laboratory practice over a two year-period. SCD patients represented a large percentage of our cases of discrepancies but we also observed a high prevalence of discrepancies between phenotypes and genotypes in blood donors. The main reasons that led to discrepancies were recent transfusions and limitations of phenotyping. Discrepancies classified as false positive phenotype/true negative genotype and false negative phenotype/true positive genotype occurred mainly in patients with recent transfusions and individuals with RH variants while those classified as true negative phenotype/false positive genotype involved null phenotypes due to silent genes. Despite the limitations of molecular methods currently employed, we found more false-negative and false-positive phenotypes than genotypes demonstrating that genotyping is more efficient to define the blood types, especially in transfusion dependent patients.

Clinical analysis of Chinese anti-low-density-lipoprotein-receptor-associated protein 4 antibodies in patients with myasthenia gravis.

Low-density-lipoprotein-receptor-associated protein 4 (LRP4) autoantibodies have recently been detected in myasthenia gravis (MG), but little is known about the clinical characteristics associated with this serological type. In this study, the clinical features of Chinese patients with anti-LRP4 antibody-positive MG were characterized. A total of 2172 MG serum samples were collected from patients in various parts of China. An enzyme-linked immunosorbent assay was used to detect acetylcholine receptor (AChR) antibody and titin antibody, and cell-based assays were used to detect muscle-specific kinase antibody and LRP4 antibody. Clinical data for patients with MG were collected from different provinces in China. In total, 16 (0.8%) patients with LRP4-MG were found amongst 2172 total patients, including three patients with AChR/LRP4-MG. Additionally, 13 (2.9%) patients with LRP4-MG were found amongst 455 patients with double seronegative MG. The ratio of males to females for these 13 patients was 1:1.6, and 53.8% patients were children. A total of 91.7% of cases exhibited initial ocular involvement, and 58.3% of cases exhibited simple eye muscle involvement. Responses to acetylcholinesterase inhibitors and prednisone were observed. The expanded sample confirmed that the positive rate of LRP4 antibodies in China is lower than that in western countries. Our results highlighted the differences between LRP4-MG and other antibody groups. Children and female patients with LRP4-MG have a higher prevalence, often involving the ocular muscles and limb muscles. The clinical symptoms are mild, and satisfactory responses to treatment are often achieved.

Infection and etiological characteristics of Vibrio cholerae in diarrhea patients in Shunyi district of Beijing, 2015–2017

ObjectiveTo understand the infection status and etiological characteristics of Vibrio cholerae in patients with food-borne diseases in Shunyi district of Beijing, and provide evidence for effective prevention, control and treatment of V. cholera infection. MethodsV. cholerae isolation and culture were conducted by using stool samples collected from diarrhea cases in surveillance from 2015 to 2017. PCR test of virulence genes, pulsed-field gel electrophoresis (PFGE), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) and antibiotic susceptibility analysis were carried out for the isolates of V. cholerae. ResultsA total of 1 105 diarrhea patients were surveyed in three years. The detection rate of V. cholerae was 0.54% (6/1 105). The detection results of cholera toxin genes ctxAB were negative. Serological typing indicated that all the strains were non-O1/O139. PCR indicated that 5 of the 6 V. cholerae strains were type III secretion system (T3SS) gene positive. The clustering results of PFGE were consistent with the clustering results of MALDI-TOF MS. ConclusionIt is necessary to attach importance to the infection and etiological surveillance of V. cholerae in food-borne disease surveillance system

Recommendations Regarding Practical DEL Typing Strategies for Serologically D-Negative Asian Donors

Background: DEL, the weakest D variant, is mistyped as D-negative by routine serological assays. Transfusion of red blood cells expressing the DEL phenotype has the potential to elicit anti-D alloimmunization in D-negative recipients. The goal of this study was to recommend DEL typing strategies for serologically D-negative Asian donors. Methods: RhCE phenotyping and the adsorption-elution test were performed on 674 serologically D-negative samples. RHD genotyping using real-time polymerase chain reaction and melting curve analysis were also undertaken to identify DEL alleles. Costs and turnaround time of RhCE phenotyping, the adsorption-elution test, and RHD genotyping were estimated. Results: Sensitivity and specificity of the adsorption-elution test for serologically D-negative samples were 94.9% (93/98) and 91.5% (527/576), respectively. C+ phenotypes were detected in all 98 samples with DEL alleles. Despite comparable costs, RHD genotyping was more accurate and rapid than the adsorption-elution test. Conclusions: Two practical DEL typing strategies using RhCE phenotyping as an initial screening method were recommended for serologically D-negative Asian donors. Compared with DEL typing using RHD genotyping, serological DEL typing using adsorption-elution test is predicted to increase the incidence of anti-D alloimmunization and decrease the D-negative donor pool without having any cost-competitiveness but can be used in laboratories where molecular methods are not applicable.

Pathogenicity of a Strain of Streptococcus suis Type 2 to Mice and Swine Isolated from Jingzhou City

Aims: The objective of this study is to identify S. suis type 2 and evaluate the virulence of ZHJ01 strain isolation, and verity the clinical and pathological outcome of a systemic infection caused by one serotype 2 when simultaneously inoculated with ZHJ01 strain. We also want to clarify the epidemiologic, clinical, microbiologic characteristics and the pathogenesis mechanism of S. suis type 2 in Hubei province, China.&#x0D; Study Design: Pigs suspected of being infected with S. suis in Jingzhou regions of Hubei province, China were studied. S. suis type 2 isolation was obtained from the suspicion of diseased pig. The case of S. suis type 2 was detected by the virulence factor amplification based on PCR detection and bacterial isolation, identification in the laboratory. According to the experimental infections of mice and piglets, pathogenicity of this S. suis type 2 isolation to mice and swine was monitored. This study was conducted in the key laboratory of pathogenic microbiology, College of Animal Science of Yangtze University, and Institute of Black Pigs Research, Yangtze University.&#x0D; Methodology: Proper serological typing can be performed using a co-agglutination test. The typical colonies purificated and cultured were inoculated with Glucose, Lactose, Raffinos, Sorbitol, D (+)-sucrose, Trehalose, 6.5%NaCl, D (-)-Salicin, Hippurate, Esculin hydrate, V-p, etc., then the test results were recorded. Detection of virulence factors were performed using PCR amplification and DNA sequencing. S.suis type 2 isolation was inoculated to mice and piglets for the virulence test, and the observation of the clinical signs and pathological changes.&#x0D; Results: The virulence factor of extracellular protein factor (EF) was determined from ZHJ01 strain based on PCR detection. Sequence analysis indicated that the isolate was very similar to nucleotide homology with others SS2 strains from different county or contries, and there was not much variation. LD50 of S. suis type 2 for mice was 2.5 x 107cfu. LD50 of S. suis type 2 for piglets was 3.92 x 109cfu.&#x0D; Conclusion: The results show that Swine S. suis type 2 has a relatively strong pathogenicity to pigs in Hubei province, China. This study can be, in part, sufficient to explain the pathogenicity for ZHJ01 strain in area of Zhijing, Jingzhou city, China, which may provide insights into the pathogenesis SS2 and more valid data to support the development of S. suis vaccine as well as the epidemiological investigation, further monitoring and effective prevention to S. suis.

Identification and typing of Yersinia enterocolitica and Yersinia pseudotuberculosis isolated from human clinical specimens in England between 2004 and 2018.

PurposeandMethodology. Epidemiological and microbiological data on Yersinia enterocolitica (n=699) and Yersinia pseudotuberculosis (n=35) isolated from human clinical specimens in England between April 2004 and March 2018 were reviewed. Traditional biochemical species identification and serological typing results were compared with species identifications and serotypes derived from whole-genome sequencing (WGS) data for a sub-set of these isolates (n=179).Results. Most Y. enterocolitica isolates were from faecal specimens (74.4%) from adults (80.7%) and 50.7 % of isolates were from male patients. Most Y. pseudotuberculosis isolates were from blood cultures (68.6%) from adults (91%) and 60.0 % of isolates were from male patients. All sequenced isolates of Y. enterocolitica (n=158) and Y. pseudotuberculosis (n=21), as well as isolates belonging to other Yersinia species (n=21), were correctly identified from genomic data using a kmer-based identification approach. Traditional phenotypic serotyping typed 82/158 and 12/21 isolates of Y. enterocolitica and Y. pseudotuberculosis, respectively, while 118/158 and 21/21 isolates of Y. enterocolitica and Y. pseudotuberculosis, respectively, were typed by the genome-derived serotyping method. In addition, WGS data provided a multi-locus sequence type profile and virulence gene profile for all isolates.Conclusion. The use of WGS for typing Y. enterocolitica and Y. pseudotuberculosis at Public Health England will facilitate the monitoring of animal-to-human transmission of these important foodborne pathogens in the UK and improve public health surveillance of the pathogenic lineages.