Streptococcus Type Research Articles

DNA sequence repeats identify numerous Type I restriction‐modification systems that are potential epigenetic regulators controlling phase‐variable regulons; phasevarions

Over recent years several examples of randomly switching methyltransferases, associated with Type III restriction‐modification (R‐M) systems, have been described in pathogenic bacteria. In every case examined, changes in simple DNA sequence repeats result in variable methyltransferase expression and result in global changes in gene expression, and differentiation of the bacterial cell into distinct phenotypes. These epigenetic regulatory systems are called phasevarions, phase‐variable regulons, and are widespread in bacteria, with 17.4% of Type III R‐M system containing simple DNA sequence repeats. A distinct, recombination‐driven random switching system has also been described in Streptococci in Type I R‐M systems that also regulate gene expression. Here, we interrogate the most extensive and well‐curated database of R‐M systems, REBASE, by searching for all possible simple DNA sequence repeats in the hsdRMS genes that encode Type I R‐M systems. We report that 7.9% of hsdS, 2% of hsdM, and of 4.3% of hsdR genes contain simple sequence repeats that are capable of mediating phase variation. Phase variation of both hsdM and hsdS genes will lead to differential methyltransferase expression or specificity, and thereby the potential to control phasevarions. These data suggest that in addition to well characterized phasevarions controlled by Type III mod genes, and the previously described Streptococcal Type I R‐M systems that switch via recombination, approximately 10% of all Type I R‐M systems surveyed herein have independently evolved the ability to randomly switch expression via simple DNA sequence repeats.

Serotype Distribution, Antimicrobial Susceptibility, and Multilocus Sequencing Type (MLST) of Streptococcus pneumoniae From Adults of Three Hospitals in Shanghai, China.

Background: Streptococcus pneumoniae, a main causative agent associated with invasive and non-invasive infection in elderly population, is a major global health problem. After pneumococcal conjugate vaccines (PCV) and pneumococcal polysaccharide vaccines (PPV) were introduced, the distribution of S. pneumoniae serotypes has changed. There was currently limited data on epidemiology and status of antimicrobial resistance of S. pneumoniae in Shanghai.Objective: To determine the serotype distribution, antimicrobial susceptibility and molecular epidemiology of S. pneumoniae isolated from adults in Shanghai.Method: A total of 75 S. pneumoniae isolates consecutively collected from 2015 through 2017 were serotyped by conventional multiplex-PCR. The antimicrobial susceptibility was determined by broth microdilution method. The multilocus sequence type (MLST) was performed to estimate the molecular epidemiology.Results: The predominant serotypes among the isolates were 19F (20.00%), 3 (16.00%), 23F (9.33%), 14 (8.00%), and19A (5.33%). The prevalence of pneumococcal strains with serotypes targeted by vaccines PCV7, PCV10, PCV13, and PPV23 was 44, 45.33, 66.67, and 80%, respectively. Penicillin non-susceptible S. pneumoniae (PNSSP) accounted for 16% of the isolates examined and resistance to erythromycin, azithromycin, tetracycline, clindamycin, cefaclor and trimethoprim-sulfamethoxazole were found in 92.00, 90.67, 86.67, 81.33, 54.67, and 54.67% of isolates, with most isolates (78.67%) presenting multidrug-resistance. The top three sequence types (STs) were ST271 (17.33%), ST180 (9.33%), and ST81 (8.00%). The international resistance clone complexes Spain23F-1 (n = 4), Netherland3-31 (n = 8), and Taiwan19F-14 (n = 14) were identified.Conclusions: The S. pneumoniae isolates showed high genetic diversity in Shanghai and the prevalence of antimicrobial resistance was also high among S. pneumoniae isolates, most of which were multidrug-resistant. The spread of international resistance clones might contribute to the increase of resistant isolates. The PPV23 could protect against most pneumococcal capsular serotypes causing infection of adults in Shanghai.

Kinetics of Serum Cytokine Profile in Mice after Injection of Supernatants of Group A Streptococci Culture.

We analyzed cytokine profile in the sera of CBA mice in 1, 5, and 24 h after intraperitoneal injection of supernatants of broth cultures of group A Streptococcus types 1M and 3M and Dochez NY5 type 10M strain. The increase of the cytokine content was observed in response to supernatants of all three types, but the highest values were recorded after injection of supernatant of strain Dochez-NY5. The level of IL-2 increased most drastically (by 51 times) and the level of IL-5 increased by 8.9 times in comparison with the control. The level of IL-2 also increased after injection of supernatants of type 1M and type 3M, but to a lesser extent (by 5 and 2.3 times, respectively). The content of proinflammatory cytokines IL-1β, TNFα, and IFNγ in mouse sera increased to a lesser extent than IL-2 after administration of all three supernatants.

Serotype distribution, antibiotic resistance pattern, and multilocus sequence types of invasive Streptococcus pneumoniae isolates in two tertiary pediatric hospitals in Beijing prior to PCV13 availability

ABSTRACT Background: Invasive pneumococcal disease (IPD) is a serious threat to children worldwide. This study reported the serotype distribution, antibiotic resistance pattern, and multilocus sequence types of 111 IPD strains isolated from children less than 14 years old in two tertiary pediatric centers in Beijing during the years 2012–2017. Methods: Serotypes were determined using Quellung reaction. Antibiotic resistance was tested using the E-test or disc diffusion method. Sequence types (STs) were assigned via multilocus sequence typing. Results: The most common serotypes of the IPD isolates were 19F, 19A, 14, 23F, and 6B, and the PCV13 coverage rate was 90.1%. For the meningitis isolates, the resistance rate to penicillin was 95.7%, and the non-susceptibility rate to ceftriaxone was 65.2%. All of the non-meningitis isolates were susceptible to penicillin, and the susceptibility rate to ceftriaxone was 89.8%. All but one of the isolates were highly resistant to erythromycin. The multidrug resistance rate of all isolates was 89.2%. The most common STs were ST320, ST271, ST876, and ST81, which belonged to serotype 19A, 19F, 14, and 23F, respectively. Conclusion: Given the high coverage rate of PCV13 and the worrisome non-susceptibility rate of IPD isolates to antibiotics, PCV13 use would be beneficial for Chinese children.

Effects of Pneumococcal Conjugate Vaccine on Genotypic Penicillin Resistance and Serotype Changes, Japan, 2010-2017.

To clarify year-to-year changes in capsular serotypes, resistance genotypes, and multilocus sequence types of Streptococcus pneumoniae, we compared isolates collected from patients with invasive pneumococcal disease before and after introductions of 7- and 13-valent pneumococcal conjugate vaccines (PCV7 and PVC13, respectively). From April 2010 through March 2017, we collected 2,856 isolates from children and adults throughout Japan. Proportions of PCV13 serotypes among children decreased from 89.0% in fiscal year 2010 to 12.1% in fiscal year 2016 and among adults from 74.1% to 36.2%. Although nonvaccine serotypes increased after introduction of PCV13, genotypic penicillin resistance decreased from 54.3% in 2010 to 11.2% in 2016 among children and from 32.4% to 15.5% among adults. However, genotypic penicillin resistance emerged in 9 nonvaccine serotypes, but not 15A and 35B. Multilocus sequence typing suggested that resistant strains among nonvaccine serotypes may have evolved from clonal complexes 156 and 81. A more broadly effective vaccine is needed.

Predicting Promiscuous T Cell Epitopes for Designing a Vaccine Against Streptococcus pyogenes.

One of the most dangerous human pathogens with high prevalence worldwide is Streptococcus pyogenes, which has major impacts on global morbidity and mortality. A major challenge for S. pyogenes vaccine development is the detection of epitopes that confer protection from infection by multiple S. pyogenes types. Our aim was to identify the most conserved and immunogenic antigens of S. pyogenes, which can be a potential candidate for vaccine design in the future. Eight important surface proteins were analyzed. Using different prediction servers, strongest epitopes were selected. They had the ability to stimulate the humoral and cell-mediated immune system. Molecular docking was performed for measuring free-binding energy of selected epitopes. Seven epitopes from three surface proteins were selected as potential candidates for vaccine development. Conservation of selected epitopes among different Streptococcus types was checked. Further in vitro and in vivo tests are required to validate the suitability of the epitopes for vaccine design.

Distribution of invasive Streptococcus pneumoniae serotypes before and 5 years after the introduction of 10-valent pneumococcal conjugate vaccine in Brazil

BackgroundIn March 2010, the 10-valent pneumococcal conjugate vaccine (PCV10) was introduced into the routine immunization program in Brazil. We describe the pneumococcal serotypes that caused invasive pneumococcal diseases (IPD) before and after the introduction of PCV10 using data from a national laboratory-based surveillance system. MethodWe compared the prevalence of vaccine types (VT) and non-vaccine types (NVT) of Streptococcus pneumoniae in three periods, pre-PCV10 (January/2005-December/2009), early post-PCV10 (January/2010-December/2013), and late post-PCV10 (January/2014-December/2015), by episode in meningitis and non-meningitis cases and by age group. Changes in serotype prevalence in the early and late post-PCV10 periods were determined using pre-PCV10 period as a reference. ResultsA total of 8971 IPD isolates from patients aged 2 months to 99 years were analyzed. In the late post-PCV10 period, the VT-IPD reduction in the 2-month to 4-year age group was 83.4% for meningitis and 87.4% for non-meningitis cases; in the age groups 5–17 years, 18–64 years, and ≥65 years, VT declined by 56.1%, 54.1%, and 47.4%, respectively, in meningitis cases, and by 60.9%, 47.7%, and 53.4%, respectively, in non-meningitis cases. NVT-IPD increased throughout the study period, driven mainly by serotypes 3, 6C, and 19A, which remained the predominant types causing IPD in the late post-PCV10 period. ConclusionWe observed direct and indirect PCV10 protection against IPD caused by VT and a shift in the distribution of serotypes 5 years after the introduction of PCV10. Continued IPD surveillance is needed to evaluate the sustainability of the high prevalence of serotypes 3, 6C, and 19A, which were not included in PCV10.

Polyresistent microflora in the structure of microorganisms divided from blood of patients of the general hospital.

The aim of our research was to evaluate the structure and the determination of the phenotypes of antibiotic resistance of microflora isolated from patients' blood in a multidisciplinary hospital during the period from 2013 to 2017. The material was taken into BacT / ALERT bottles containing nutrient media, followed by incubation of blood. In case of a positive result, the material from the vials was dispersed into dense nutrient media. Species identification was carried out using commercial biochemical API test systems and MALDITOF mass spectrometry. The antibiotic resistance of the isolated microorganisms was evaluated by a classical disc-diffusion method. From 2013 to 2017, 3504 blood tests were performed, of which 16.8% were positive. Of the isolated strains, 69.6% were Gram-positive, 27% were Gram-negative, and 3.4% were fungi. The structure of Gram-positive bacteria included Staphylococcus spp - 71.46%, Enterococcus spp. - 21.22% and Streptococcus spp - 7.32%. Staphylococcus aureus (47,8%) prevailed among staphylococci (in 62.14% were methicillin-resistant) and coagulase-negative staphylococci. Among the genus Enterococcus spp, Enterococcus faecalis prevailed (27% resistant to macrolides, 14% to fluoroquinolones) and Enterococcus faecium (69% resistant to penicillins, fluoroquinolones, macrolides). Streptococcus pneumoniae, Streptococcus pyogenes and streptococci from the group of alpha-greening were isolated from streptococci. Clinically significant types of streptococci in 33.3% were resistant to macrolides and fluoroquinolones. In the structure of gram-negative bacteria, Enterobacteriaceae prevailed - 71.07% (Klebsiella pneumoniae, E. coli); the proportion of non-fermenting Gram-negative bacteria (NFGOB) was 28.93%. Most Gram-negative bacteria were producers of extended-spectrum beta-lactamases (BLBRs). In NFGOB structure allocated Acinetobacter baumanii - 56,5% (81% polyresistant), Pseudomonas aeruginosa - 30,4% (50% - Carbapenemase Producing Organisms), Stenotrophomonas maltophilia - 10,9%. Thus, microbiological research in septic blood conditions is an integral part of the diagnostic search, selection of etiotropic therapy and monitoring of its effectiveness.

External Quality Assurance for Laboratory Identification and Capsular Typing of Streptococcus pneumoniae

An external quality assessment (EQA) scheme for pneumococcal serotype identification has been performed over a period of 11 years, by a network of European pneumococcal reference laboratories. We report the results from the EQA, and present an assessment of the acceptability and utility of the EQA scheme. Reports from 22 EQA panels distributed in 2005–2016 were analysed. Each EQA panel consisted of seven isolates. A questionnaire including seven questions related to the acceptability and utility of the EQA scheme was distributed to all participating laboratories. Altogether, 154 pneumococcal isolates were tested. Of the 92 serologically distinct serotypes currently defined, 49 serotypes were included in the rounds. Discrepant results were observed in eight EQA rounds, involving 11 isolates (7.1%, 95% CI: 4% to 12%). All participating laboratories reported that the EQA scheme was useful for quality assurance purposes. Our results show that comparable serotyping data can be obtained in different laboratories. The EQA participation helps to keep the typing procedures at a high standard and provides data for accreditation purposes. The EQA is helpful when new technologies are introduced, and reveal limitations of both genotypic and phenotypic methods. Continuation of the presented EQA scheme is planned.

Clinical study of neonatal septicemia with reference to early indicators of sepsis

Background: The use of CRP (C-reactive protein) in early diagnosis of neonatal septicemia. The usefulness of CRP in early detection of neonatal septicemia/meningitis and urinary tract infection was studied in a neonatal unit using a semi-quantitative latex-agglutination as a rapid screening method and electroimmuno assay as reference method for CRP determination.Methods: The present study was conducted among 150 patients 218 samples were taken for serum globulin determinations. Additionally, all infants born at the hospital throughout August 2016 to February 2017 with a designation of blood disease, infectious disease or tract infection (UTI) were retrospectively studied. Depending on the clinical course and therefore the results of the culture the 110 infants were divided into four groups.Results: The 110 infants in 92% of non-infected infants CRP was 16 mg/l and 80% had CRP <10 mg/l up to 3 days of age. After 3 days of age 93% had CRP <12 mg/l. The initial CRP level was increased in 9 out of 11 patients (82%) with bacterial septicemia. Low CRP was seen in one patient with total agranulocytosis and septicemia from Streptococcus type B and in one patient with Staphylococcus albus sepsis. A rise in CRP was also seen in very pre-term infants with septicemia. Increased initial CRP was uncommon in neonatal urinary tract infection (2 of 9) but a rise was seen in 3 additional patients.Conclusions: A comparison between CRP, total neutrophil blood cell count and hand neutrophil count as diagnostic parameters was in favor of CRP at this early stage of infection. CRP is of definite value as an aid in early diagnosis of neonatal septicemia and bacterial meningitis.

Development of PCRSeqTyping\u2014a novel molecular assay for typing of Streptococcus pneumoniae

BackgroundPrecise serotyping of pneumococci is essential for vaccine development, to better understand the pathogenicity and trends of drug resistance. Currently used conventional and molecular methods of serotyping are expensive and time-consuming, with limited coverage of serotypes. An accurate and rapid serotyping method with complete coverage of serotypes is an urgent necessity. This study describes the development and application of a novel technology that addresses this need.MethodsPolymerase chain reaction (PCR) was performed, targeting 1061 bp cpsB region, and the amplicon was subjected to sequencing. The sequence data was analyzed using the National Centre for Biotechnology Information database. For homologous strains, a second round of PCR, sequencing, and data analysis was performed targeting 10 group-specific genes located in the capsular polysaccharide region. Ninety-one pneumococcal reference strains were analyzed with PCRSeqTyping and compared with Quellung reaction using Pneumotest Kit (SSI, Denmark).ResultsA 100% correlation of PCRSeqTyping results was observed with Pneumotest results. Fifty-nine reference strains were uniquely identified in the first step of PCRSeqTyping. The remaining 32 homologous strains out of 91 were also uniquely identified in the second step.ConclusionThis study describes a PCRSeqTyping assay that is accurate and rapid, with high reproducibility. This assay is amenable for clinical testing and does not require culturing of the samples. It is a significant improvement over other methods because it covers all pneumococcal serotypes, and it has the potential for use in diagnostic laboratories and surveillance studies.

Ongoing outbreak of invasive and non-invasive disease due to group A Streptococcus (GAS) type emm66 among homeless and people who inject drugs in England and Wales, January to December 2016.

We report an outbreak of invasive and non-invasive disease due to an unusual type of Streptococcus pyogenes(group A Streptococcus, emm66) among a vulnerable, largely homeless population in southern England and Wales, detected in September 2016. Twenty-seven confirmed cases were subsequently identified between 5 January and 29 December 2016; 20 injected drugs and six reported problematic alcohol use. To date, we have ruled out drug-related vehicles of infection and identified few common risk factors.

Synthesis of Group B Streptococcus type III polysaccharide fragments for evaluation of their interactions with monoclonal antibodies

Abstract Group B Streptococcus type III (GBSIII) is the most relevant serotype among GBS strains causing infections and the potential of its capsular polysaccharide conjugated to a protein carrier as vaccine is well documented. Polysaccharide from GBSIII (PSIII) can form helical structures in solution where negatively charged sialic acid residues would be disposed externally providing stabilization to the helix. A peculiar high affinity to specific monoclonal antibodies (mAbs) has been reported for PSIII, and fragments of diverse size bind to mAbs in a length dependent manner. These data have been rationalized in terms of conformational epitopes that would be formed by fragments with >4 saccharidic repeating units. Saturation Transfer Difference NMR experiments have demonstrated that the sialic acid residue is not involved in antibody recognition. However the molecular basis of the interaction between PSIII and mAbs has not been fully elucidated. An important prerequisite to achieve this would be the availability of the three possible sugar sequences representing the pentasaccharide PSIII repeating unit. Herein we established a [2+3] convergent approach leading to these three pentasaccharides (1–3) with the end terminal sugar bearing a linker for possible conjugation. The PSIII fragments were coupled to the genetically detoxified diphtheria toxin CRM197 to prove by ELISA that the three pentasaccharides are recognized by polyclonal anti-PSIII serum. The presence of the branching formed by a Glc residue β-(1→6) linked to GlcNAc was proven an important motif for antibody recognition.

Genomic Characteristics Behind the Spread of Bacteremic Group A Streptococcus Type emm89 in Finland, 2004-2014.

Background. Many countries worldwide have reported increasing numbers of emm89 group A Streptococcus (GAS) infections during last decade. Pathogen genetic factors linked to this increase need assessment.Methods. We investigated epidemiological characteristics of emm89 GAS bacteremic infections, including 7-day and 30-day case-fatality rates, in Finland during 2004–2014 and linked them to whole-genome sequencing data obtained from corresponding strains. The Fisher exact test and exact logistic regression were used to compare differences between bacteremic infections due to emm89 GAS belonging to different genetic clades and subclades.Results. Out of 1928 cases of GAS bacteremic infection, 278 were caused by emm89 GAS. We identified 2 genetically distinct clades, arbitrarily designated clade 2 and clade 3. Both clades were present during 2004–2008, but clade 3 increased rapidly from 2009 onward. Six subclades (designated subclades A–F) were identified within clade 3, based on phylogenetic core genome analysis. The case-fatality rate differed significantly between subclades (P < .05), with subclade D having the highest 30-day estimated case-fatality rate (19% vs 3%–14%).Conclusions. A new emm89 clone, clade 3, emerged in 2009 and spread rapidly in Finland. Patients infected with certain subclades of clade 3 were significantly more likely to die. A specific polymerase chain reaction assay was developed to follow the spread of subclade D in 2015.

Emerging Streptococcus pneumoniae Strains Colonizing the Nasopharynx in Children After 13-valent Pneumococcal Conjugate Vaccination in Comparison to the 7-valent Era, 2006-2015.

After introduction of the 7-valent pneumococcal conjugate vaccine (PCV7) in the United States in 2000, emergence of replacement serotypes occurred, leading to the introduction of a 13-valent pneumococcal conjugate vaccine (PCV13) in 2010 that contained all PCV7 serotypes plus 6 additional serotypes (1, 3, 5, 6A, 7F and 19A). Here, we describe a 9-year prospective, longitudinal study characterizing Streptococcus pneumoniae strains colonizing the nasopharynx (NP) of young children based on serotype, sequence type (ST) and antibiotic susceptibility during the PCV7 and PCV13 eras. NP samples were obtained for pneumococcal identification from prospectively followed children at 6, 9, 12, 15, 18, 24 and 30 months of age. A total of 1072 visits during the PCV7 era (June 2006 to September 2010) and 2044 visits during the PCV13 era (October 2010 to September 2015) were included from 665 children. Serotyping and multilocus sequence typing types of Streptococcus pneumoniae isolates were evaluated along with their antibiotic resistance pattern. A total of 1045 Streptococcus pneumoniae were isolated; 350 during the PCV7 era and 685 during the PCV13 era. The most common serotypes identified during the PCV7 era were 19A and 23B compared with 35B, 23B and 21 in PCV13 era. Serotypes 15A/B/C emerged in equal proportion during the PCV13 era. Serotypes 16 and 20 were only observed in the PCV13 era. NP carriage of 19A persisted 5 years after PCV13 introduction (5% of all isolates). Multilocus ST 199 remained a dominant ST during both the PCV7 and PCV13 eras, and ST558 and ST62 emerged after PCV13. Antibiotic resistance to penicillin, ceftriaxone, cefotaxime, erythromycin, tetracycline and trimethoprim/sulfamethoxazole significantly decreased from the PCV7 to the PCV13 era. Serotypes 35B, 23B, 21 and 15A/B/C rapidly emerged as NP colonizers in the early PCV13 era. Genetically divergent strains with ST558 and ST62 emerged. Resistance to common antibiotics declined after the introduction of PCV13.

MLVA Typing of Streptococcus pneumoniae Isolates with Emphasis on Serotypes 14, 9N and 9V: Comparison of Previously Described Panels and Proposal of a Novel 7 VNTR Loci-Based Simplified Scheme.

Streptococcus pneumoniae remains as an important cause of community-acquired bacterial infections, and the nasopharynx of asymptomatic carriers is the major reservoir of this microorganism. Pneumococcal strains of serotype 14 and serogroup 9 are among the most frequently isolated from both asymptomatic carriers and patients with invasive disease living in Brazil. Internationally disseminated clones belonging to such serotypes have been associated with the emergence and spread of antimicrobial resistance in our setting, highlighting the need for epidemiological tracking of these isolates. In this scenario, Multiple Loci VNTR Analysis (MLVA) has emerged as an alternative tool for the molecular characterization of pneumococci, in addition to more traditional techniques such as Multi-Locus Sequence Typing (MLST) and Pulsed-Field Gel Electrophoresis (PFGE). In the present study, 18 VNTR loci, as well as other previously described reduced MLVA panels (7 VNTR loci), were evaluated as tools to characterize pneumococcal strains of serotypes 14, 9N and 9V belonging to international and regional clones isolated in Brazil. The 18 VNTR loci panel was highly congruent with MLST and PFGE, being also useful for indicating the genetic relationship with international clones and for discriminating among strains with indistinguishable STs and PFGE profiles. Analysis of the results also allowed deducing a novel shorter 7 VNTR loci panel, keeping a high discriminatory power for isolates of the serotypes investigated and a high congruence level with MLST and PFGE. The newly proposed simplified panel was then evaluated for typing pneumococcal strains of other commonly isolated serotypes. The results indicate that MLVA is a faster and easier to perform, reliable approach for the molecular characterization of S. pneumoniae isolates, with potential for cost-effective application, especially in resource-limited countries.

The Relationship between Different Types of Streptococci and Pharyngotonsillitis: A Systematic Review

Introduction: Streptococci were initially viewed by Louis Pasteur in 1879. Brown, in 1919, created the first systematized classification of streptococci in α, β and γ. Rebecca Lancefield contributed for knowledge of streptococcal polysaccharides discovering groups and M cell wall protein. Streptococci are gram positive, catalase and oxidase negative. Streptococci related to pathogenesis of acute sore throat are Streptococcus β-hemolytic of the groups A, B, C, F and G. Objective: Our objective was to make a review of the different types of streptococcus that can cause infection in the oropharynx. Review: Streptococcus pyogenes is belonging to the Lancefield grouping. Skin and mucous membranes of humans are the only known reservoir in the nature of streptococcus group A. Streptococcus of Group B (SGB) was originally isolated by Nocard in 1887. The primary habitat of these bacteria is the human colon, although it may colonize the oropharynx and especially, the vagina. For this reason, in mid-1960, the SGB has become a major cause of perinatal bacterial infection, including bacteremia and urinary tract infection in pregnant women. Group C is involved in purulent pharyngitis outbreaks. According to Fox et al, Streptococcus anginosus is the most common isolate β-hemolytic group C in the oropharynx. Streptococcus Group C (SGC) is reported as “pyogenes-like” because it shares important virulence factors such as hemolysins, extracellular enzymes and M proteins as well as the SGA. Conclusion: We conclude that it’s important to have knowledge about the different types of streptococci to better treat patients with sore throats and problems associated with this condition.

Coupling Peptide Antigens to Virus-Like Particles or to Protein Carriers Influences the Th1/Th2 Polarity of the Resulting Immune Response.

We have conjugated the S9 peptide, a mimic of the group B streptococcal type III capsular polysaccharide, to different carriers in an effort to elicit an optimal immune response. As carriers, we utilized the soluble protein keyhole limpet hemocyanin and virus-like particles (VLPs) from two plant viruses, Cowpea Chlorotic Mottle Virus and Cowpea Mosaic Virus. We have found that coupling the peptide to the soluble protein elicits a Th2 immune response, as evidenced by the production of the peptide-specific IgG1 antibody and IL-4/IL-10 production in response to antigen stimulation, whereas the peptide conjugated to VLPs elicited a Th1 response (IgG2a, IFN-γ). Because the VLPs used as carriers package RNA during the assembly process, we hypothesize that this effect may result from the presence of nucleic acid in the immunogen, which affects the Th1/Th2 polarity of the response.

Successive Administration of Streptococcus Type 5 Group A Antigens and S. typhimurium Antigenic Complex Corrects Elevation of Serum Cytokine Concentration and Number of Bone Marrow Stromal Pluripotent Cells in CBA Mice Induced by Each Antigen Separately.

Administration of bacterial antigens to CBA mice induced an increase in serum concentration of virtually all cytokines with a peak in 4 h after administration of S. typhimurium antigens and in 7 h after administration of streptococcus antigens. In 20 h, cytokine concentrations returned to the control level or were slightly below it. In 4 h after administration of S. typhimurium antigens preceded 3 h before by administration of streptococcus antigens, we observed a significant decrease in serum concentrations of IFN-γ, IL-10, GM-CSF, IL-12, and TNF-α, in comparison with injection S. typhimurium antigens alone and IL-5, IL-10, GM-CSF, and TNF-α in comparison with injection of streptococcus antigens alone; the concentrations of IL-2 and IFN-γ, in contrast, increased by 1.5 times in this case. In 20 h after administration of S. typhimurium antigens, the number of multipotential stromal cells (MSC) in the bone marrow and their cloning efficiency (ECF-MSC) increased by 4.8 and 4.4 times, respectively, in comparison with the control, while after administration of streptococcus antigens by 2.6 and 2.4 times, respectively. In 20 h after administration of S. typhimurium antigens preceded 3 h before by administration of streptococcus antigens, these parameters increased by 3.2 and 2.9 times, respectively, in comparison with the control, i.e. the observed increase in the level of MSC count and ECF-MSC is more consistent with the response of the stromal tissue to streptococcus antigens. Thus, successive administration of two bacterial antigens corrected both serum cytokine profiles and MSC response to administration of each antigen separately, which indicates changeability of the stromal tissue in response to changes in the immune response.

Capsular typing of Streptococcus pneumoniae isolated in an Algerian hospital using a new multiplex PCR-based scheme

We developed a new sequential multiplex-PCR-based typing scheme (MPBTS) for pneumococcal capsular classification. The serogroup/type of 37 control isolates obtained by the Quellung reaction, MPBTS, and nucleotide sequencing, were fully concordant. The serogroups/types of 75 invasive isolates determined by MPBTS, presented 100% specificity and 96% sensitivity, when compared with the Quellung reaction.