Virulent Serotype Research Articles

IgA1 Protease as a Vaccine Basis for Prevention of Bacterial Meningitis

The review covers the study of the protective properties of IgA1 protease and the possibility of creating a vaccine preparation for the prevention of bacterial meningitis of various origins on its basis. Bacterial meningitis belongs to the group of socially dangerous diseases and is characterized by a severe course, numerous complications and high mortality. The approaches used at present in world practice to create antimicrobial vaccines are based on a narrow targeting against a specific pathogen. The development of a monocomponent vaccine against a wide range of bacterial pathogens with a common virulence factor is still relevant. IgA1 protease, a protein that is one of the main virulence factors of a number of gram-negative and gram-positive bacteria, can serve as such an antigen. Bacterial IgA1 protease is uniquely specific for immunoglobulins A1 (IgA1), cleaving peptide bonds in the hinge regions of the IgA1 in humans and other higher primates. Bacteria, getting on the mucous membrane, destroy IgA1, which acts as the first barrier to protect the body from infections. Neutralization of IgA1 protease at this stage can become an obstacle to the development of infection, hindering the adhesion of a number of pathogens that produce this protein. The data available in the literature on the mechanism of antibacterial protection are scattered and ambiguous. The review considers the literature data and the results of our own experiments on the protective activity of IgA1 protease. We have shown that the recombinant meningococcal IgA1 protease and some of its fragments protect mice from infection with a live virulent culture not only of meningococci of the main epidemic serogroups (A, B, C, and W135), but also of some of the most common virulent pneumococcal serotypes. The data obtained indicate the possibility of creating a monocomponent vaccine against these and, possibly, other bacterial infections. Currently, significant progress has been made in studying the structure and functions of secreted proteins in the bacteria Neisseria meningitidis and Haemophilus influenzae. In this review we describe protein translocation systems of N. meningitidis, which are related to the secretion of proteins in these bacteria, and also present modern data on the functions of these proteins. Analysis of experimental data on the structure of IgA1 protease of N. meningitidis and the formation of immunity during vaccination is of key importance in the development of prophylactic preparations.

Comparative Exoproteome Analysis of Streptococcus suis Human Isolates.

The swine pathogen Streptococcus suis is a Gram-positive bacterium which causes infections in pigs, with an impact in animal health and in the livestock industry, and it is also an important zoonotic agent. During the infection process, surface and secreted proteins are essential in the interaction between microorganisms and their hosts. Here, we report a comparative proteomic analysis of the proteins released to the extracellular milieu in six human clinical isolates belonging to the highly prevalent and virulent serotype 2. The total secreted content was precipitated and analyzed by GeLC-MS/MS. In the six strains, 144 proteins assigned to each of the categories of extracellular or surface proteins were identified, as well as 680 predicted cytoplasmic proteins, many of which are putative moonlighting proteins. Of the nine predicted signal peptide-I secreted proteins, seven had relevant antigenic potential when they were analyzed through bioinformatic analysis. This is the first work comparing the exoproteome fraction of several human isolates of this important pathogen.

Anatomical Site, Typing, Virulence Gene Profiling, Antimicrobial Susceptibility and Resistance Genes of Streptococcus suis Isolates Recovered from Pigs in Spain.

A set of 207 Streptococcus suis isolates were collected from ten autonomous communities from Spain in 2019 to 2020 from pigs with meningitis, pneumonic lungs, arthritic joints or other swollen viscera, to a lesser extent. Thirteen capsular types were detected being the most prevalent serotype 2 (21.7%), followed by serotypes 1 (21.3%), 9 (19.3%) and 3 (6.3%). Serotypes 2 and 9 were recovered mainly from the central nervous system (CNS), while serotype 1 was isolated mostly from swollen joints and serotype 3 from the lungs. Twenty-five isolates (12.1%) could not be typed. The most prevalent pathotype was epf + mrp + sly + luxS (49 isolates, 23.8%), and it was related mainly to serotypes 1 and 2. Serotypes 1–3 and 9 were significantly associated with anatomical sites of isolation and virulence factors, serotype 9 (CNS) and serotypes 3 and 9 (lungs) being associated with virulence profiles without the epf gene. S. suis isolates showed globally high antimicrobial resistances, but ampicillin followed by spectinomycin and tiamulin resulted in the highest activities, while the greatest resistances were detected for sulphadimethoxine, tetracyclines, neomycin, clindamycin and macrolides. A total of 87.4% isolates were positive to the tetO gene, 62.4% to the ermB gene and 25.2% to the fexA gene, while 14.6% were positive to all three genes simultaneously. A significative association between isolate resistances to tetracyclines and macrolides and the resistance genes tested was established, except for phenicol resistance and the fexA gene. A set of 14 multiresistance patterns were obtained according to the number of antimicrobials to which the isolates were resistant, the resistances to 12 or more agents being the most prevalent ones. A remarkable amount of multiresistance profiles could be seen among the S. suis serotype 9 isolates.

Isolation and molecular characterization of a virulent Marek's Disease virus serotype-1from Andhra Pradesh, India.

Marek's disease (MD) is one of the most significant neoplastic diseases of poultry caused by Marek's disease virus (MDV), an oncogenic avian herpesvirus which is responsible for great economic losses to the poultry industry worldwide. MD is being manifested as an acute disease with lymphomas in multiple visceral organs. In the present study, an outbreak of MD was investigated in one of the poultry farms from Andhra Pradesh, India. The gross lesions in the affected birds included lymphomas in different visceral organs like liver, spleen, proventriculus, heart and ovaries. Histopathology revealed presence of uniform lymphoblastoid cell infiltration typical of MD. The isolation of the virus was carried out in duck embryo fibroblast cells. After three blind passages, the cell cultures revealed plaque formation typical of MDV. Further confirmation of the virus was carried out by PCR targeting 132 bp repeats of serotype‑1 MDV and the oncogenes Meq and vIL‑8 were amplified and sequenced. The nucleotide and phylogenetic analysis of the virus confirmed the virus as virulent serotype‑ 1 MDV. The present outbreak suggests the need for change in the vaccination regimen of MD vaccination with appropriate serotype‑ 1 MD vaccines in Indian poultry flocks as the HVT and bivalent vaccines are unable to protect the flocks against virulent MDV.

Prevalence, characterization and antibiotic resistance of Shiga toxigenic Escherichia coli serogroups isolated from fresh beef and locally processed ready-to-eat meat products in Lagos, Nigeria

Fresh beef and meat products have been implicated in outbreaks of Shiga toxin-producing Escherichia coli (STEC) worldwide. This study investigated the prevalence of E. coli O157: H7 and non-O157 STEC serogroups in fresh beef in the open market and street vended meat products (n = 180) in Lagos metropolis, Nigeria. A combination of culture media and immunomagnetic separation followed by typing for associated virulence factors and serotypes was performed. Antimicrobial susceptibility testing was performed on the isolated STEC serotypes using the disk diffusion method. A total of 72 STEC serogroup isolates were detected from 61 out of 180 samples. The O157 STEC serotypes were detected in fresh beef, suya, minced meat and tsire with prevalence of 20.8% while non-O157 STEC serogroups were detected in all the samples. Molecular typing revealed 25% (n = 18) of the STEC serogroups showed presence of all the stx1, stx2, eaeA, fliCH7 and rfbEO157 virulence factors while 54.2% (n = 39) possessed a combination of two virulence genes. Multidrug resistance was discovered in 23.6% (n = 17) of the total STEC serogroups. Locally processed ready-to-eat meat products in Lagos metropolis, Nigeria harbour potentially pathogenic multi-drug resistant STEC serogroups that can constitute public health hazard.

Virulent African horse sickness virus serotype 4 interferes with the innate immune response in horse peripheral blood mononuclear cells in vitro.

African horse sickness (AHS) is caused by African horse sickness virus (AHSV), a double stranded RNA (dsRNA) virus of the genus Orbivirus, family Reoviridae. For the development of new generation AHS vaccines or antiviral treatments, it is crucial to understand the host immune response against the virus and the immune evasion strategies the virus employs. To achieve this, the current study used transcriptome analysis of RNA sequences to characterize and compare the innate immune responses activated during the attenuated AHSV serotype 4 (attAHSV4) (in vivo) and the virulent AHSV4 (virAHSV4) (in vitro) primary and secondary immune responses in horse peripheral blood mononuclear cells (PBMC) after 24h. The pro-inflammatory cytokine and chemokine responses were negatively regulated by anti-inflammatory cytokines, whereas the parallel type I and type III IFN responses were maintained downstream of nucleic acid sensing pattern recognition receptor (PRR) signalling pathways during the attAHSV4 primary and secondary immune responses. It appeared that after translation, virAHSV4 proteins were able to interfere with the C-terminal IRF association domain (IAD)-type 1 (IAD1) containing IRFs, which inhibited the expression of type I and type III IFNs downstream of PRR signalling during the virAHSV4 primary and secondary immune responses. Viral interference resulted in an impaired innate immune response that was not able to eliminate virAHSV4-infected PBMC and gave rise to prolonged expression of pro-inflammatory cytokines and chemokines during the virAHSV4 induced primary immune response. Indicating that virAHSV4 interference with the innate immune response may give rise to an excessive inflammatory response that causes immunopathology, which could be a major contributing factor to the pathogenesis of AHS in a naïve horse. Viral interference was overcome by the fast kinetics and increased effector responses of innate immune cells due to trained innate immunity and memory T cells and B cells during the virAHSV4 secondary immune response.

Population structure and genetic diversity of non-O157 Shiga toxin-producing Escherichia coli (STEC) clinical isolates from Michigan

Non-O157 STEC are increasingly linked to foodborne infections, yet little is known about the diversity and molecular epidemiology across locations. Herein, we used whole genome sequencing to examine genetic variation in 894 isolates collected from Michigan patients between 2001 and 2018. In all, 67 serotypes representing 69 multilocus sequence types were identified. Serotype diversity increased from an average of four (2001–2006) to 17 (2008–2018) serotypes per year. The top six serogroups reported nationally caused > 60% of infections in 16 of the 18 years; serogroups O111 and O45 were associated with hospitalization as were age ≥ 65 years, diarrhea with blood and female sex. Phylogenetic analyses of seven multilocus sequence typing (MLST) loci identified three clades as well as evidence of parallel evolution and recombination. Most (95.5%) isolates belonged to one clade, which could be further differentiated into seven subclades comprising isolates with varying virulence gene profiles and serotypes. No association was observed between specific clades and the epidemiological data, suggesting that serogroup- and serotype-specific associations are more important predictors of disease outcomes than lineages defined by MLST. Molecular epidemiological studies of non-O157 STEC are important to enhance understanding of circulating strain distributions and traits, genetic variation, and factors that may impact disease risk and severity.

Whole genomic comparative analysis of Streptococcus pneumoniae serotype 1 isolates causing invasive and non-invasive infections among children under 5 years in Casablanca, Morocco

BackgroundStreptococcus pneumoniae serotype 1 remains a leading cause of invasive pneumococcal diseases, even in countries with PCV-10/PCV-13 vaccine implementation. The main objective of this study, which is part of the Pneumococcal African Genome project (PAGe), was to determine the phylogenetic relationships of serotype 1 isolates recovered from children patients in Casablanca (Morocco), compared to these from other African countries; and to investigate the contribution of accessory genes and recombination events to the genetic diversity of this serotype.ResultsThe genome average size of the six-pneumococcus serotype 1 from Casablanca was 2,227,119 bp, and the average content of coding sequences was 2113, ranging from 2041 to 2161. Pangenome analysis of the 80 genomes used in this study revealed 1685 core genes and 1805 accessory genes. The phylogenetic tree based on core genes and the hierarchical bayesian clustering analysis revealed five sublineages with a phylogeographic structure by country. The Moroccan strains cluster in two different lineages, the five invasive strains clusters altogether in a divergent clade distantly related to the non-invasive strain, that cluster with all the serotype 1 genomes from Africa.ConclusionsThe whole genome sequencing provides increased resolution analysis of the highly virulent serotype 1 in Casablanca, Morocco. Our results are concordant with previous works, showing that the phylogeography of S. pneumoniae serotype 1 is structured by country, and despite the small size (six isolates) of the Moroccan sample, our analysis shows the genetic cohesion of the Moroccan invasive isolates.

Subcutaneous abscess caused by Streptococcus pneumoniae serotype 28F in an infant: a case report

BackgroundInvasive pneumococcal disease (IPD) is defined by the detection of Streptococcus pneumoniae on culture from samples obtained from a normally sterile site. Pneumococcal conjugate vaccines (PCV) have been developed for the prevention of IPD that is caused by highly virulent serotypes. Despite the effective reduction of IPD caused by vaccine serotypes after the introduction of PCV, there has been a rapid increase in the incidence of IPD caused by non-vaccine serotypes, and serotype replacement has become a global issue.Case presentationWe report a previously healthy 4-month-old girl presenting with a large subcutaneous abscess caused by S. pneumoniae, identified as non-vaccine serotype 28F. The patient had received routine vaccination, including PCV vaccination. After the incision and drainage of the subcutaneous abscess, the patient was treated with antibiotics. She was discharged on Day 7 of hospitalization without any residual sequelae.ConclusionsSubcutaneous abscess is a common pediatric skin and soft tissue infection, whereas pneumococcal subcutaneous abscesses are quite rare. As the pneumococcal serotype 28F caused a subcutaneous abscess, this serotype possibly has a high virulence. The incidence of IPD caused by non-vaccine serotypes, such as 28F, is expected to increase in the future. The consolidation of international data on pneumococcal serotypes is important for the development of novel PCV.

PspA Diversity, Serotype Distribution and Antimicrobial Resistance of Invasive Pneumococcal Isolates from Paediatric Patients in Shenzhen, China.

IntroductionTo determine the phenotypes and genotypes of invasive Streptococcus pneumoniae (S. pneumoniae), 108 strains were isolated from paediatric patients with invasive pneumococcal diseases (IPDs) in Shenzhen from 2014 to 2018.MethodsSerotype profiles were defined by multiplex PCR of the capsule gene. Pneumococcal surface protein A (PspA) classification was performed through pspA gene sequencing. Antimicrobial resistance was examined by broth microdilution. Multilocus sequence typing (MLST) was determined based on next-generation sequencing data.ResultsEighty-one S. pneumoniae of 17 serotypes were finally collected. The coverage of the 13-conjugated polysaccharide vaccine (PCV13) was 88.9%. After the introduction of PCV13, the nonvaccine serotypes were added by serotypes 15b, 16F and 20. Vaccine serotype 3 increased by four serious cases. The pspA family 1 and pspA family 2 are predominant. The multiple drug resistance rate is 91.3%. None of the nonmeningitis isolates were resistant to penicillin, while 98.8% of all the isolates were resistant to erythromycin.DiscussionThis work characterizes the molecular epidemiology of invasive S. pneumoniae in Shenzhen. Continued surveillance of serotype distribution and antimicrobial susceptibility is necessary to alert antibiotic-resistant nonvaccine serotypes and highly virulent serotypes.

Prevalence and serotypes of Shiga toxin-producing Escherichia coli (STEC) in dairy cattle from Northern Portugal.

The prevalence of Shiga toxin (Stx)-producing Escherichia coli (STEC) was determined by evaluating its presence in faecal samples from 155 heifers, and 254 dairy cows in 21 farms at North of Portugal sampled between December 2017 and June 2019. The prevalence of STEC in heifers (45%) was significantly higher than in lactating cows (16%) (p<0.05, Fisher exact test statistic value is <0.00001). A total of 133 STEC were isolated, 24 (13.8%) carried Shiga-toxin 1 (stx1) genes, 69 (39.7%) carried Shiga-toxin 2 (stx2) genes, and 40 (23%) carried both stx1 and stx2. Intimin (eae) virulence gene was detected in 29 (21.8%) of the isolates. STEC isolates belonged to 72 different O:H serotypes, comprising 40 O serogroups and 23 H types. The most frequent serotypes were O29:H12 (15%) and O113:H21 (5.2%), found in a large number of farms. Two isolates belonged to the highly virulent serotypes associated with human disease O157:H7 and O26:H11. Many other bovine STEC serotypes founded in this work belonged to serotypes previously described as pathogenic to humans. Thus, this study highlights the need for control strategies that can reduce STEC prevalence at the farm level and, thus, prevent food and environmental contamination.

Actinobacillus pleuropneumoniae: a review of an economically important pathogen

Actinobacillus pleuropneumoniae is one of the causative agents of porcine pleuropneumonia, which is an economically important respiratory disease of pig production. Clinical signs vary based on the severity of disease and lung lesions present, but include fever and severe respiratory signs including coughing and laboured breathing. Numerous serotypes exist which vary in their virulence, and virulence of serotypes has also been shown to be vary between countries. It is important to establish which serotypes are present and active on a farm as well as carrying out seroprofiling to determine the correct time for implementation of control measures such as vaccination. Understanding of transmission routes is vital, including the role of carrier animals on the farm which are persistently infected and can shed the bacteria, therefore infecting other animals. Therefore, as with all infectious diseases, good standards of internal and external biosecurity are important in controlling the disease on farm. Vaccination has been shown to be effective on affected farms in preventing outbreaks, reducing clinical signs if they occur, and most important to the farmer, preventing losses in mortality, feed conversion ratio and growth. Therefore, vaccines are often a good choice for controlling pleuropneumonia on farm and reducing the need for treatment using antimicrobials.

Therapeutic Activity of Type 3 Streptococcus pneumoniae Capsule Degrading Enzyme Pn3Pase.

PurposeStreptococcus pneumoniae (Spn) serotype 3 (Spn3) is considered one of the most virulent serotypes with resistance to conventional vaccine and treatment regimens. Pn3Pase is a glycoside hydrolase that we have previously shown to be highly effective in degrading the capsular polysaccharide of type 3 Spn, sensitizing it to host immune clearance. To begin assessing the value and safety of this enzyme for future clinical studies, we investigated the effects of high doses of Pn3Pase on host cells and immune system.MethodsWe assessed the enzyme’s catalytic activity following administration in mice, and performed septic infection models to determine if prior administration of the enzyme inhibited repeat treatments of Spn3-challenged mice. We assessed immune populations in mouse tissues following administration of the enzyme, and tested Pn3Pase toxicity on other mammalian cell types in vitro.ResultsRepeated administration of the enzyme in vivo does not prevent efficacy of the enzyme in promoting bacterial clearance following bacterial challenge, with insignificant antibody response generated against the enzyme. Immune homeostasis is maintained following high-dose treatment with Pn3Pase, and no cytotoxic effects were observed against mammalian cells.ConclusionsThese data indicate that Pn3Pase has potential as a therapy against Spn3. Further development as a drug product could overcome a great hurdle of pneumococcal infections.

Binding Mechanism Elucidation of the Acute Respiratory Disease Causing Agent Adenovirus of Serotype 7 to Desmoglein-2

The study of viruses causing acute respiratory distress syndromes (ARDS) is more essential than ever at a time when a virus can create a global pandemic in a matter of weeks. Among human adenoviruses, adenovirus of serotype 7 (HAdV7) is one of the most virulent serotypes. This virus regularly re-emerges in Asia and has just been the cause of several deaths in the United States. A critical step of the virus life cycle is the attachment of the knob domain of the fiber (HAd7K) to the cellular receptor desmoglein-2 (DSG2). Complexes between the fiber knob and two extracellular domains of DSG2 have been produced. Their characterization by biochemical and biophysical methods show that these two domains are sufficient for the interaction and that the trimeric HAd7K could accommodate up to three DSG2 receptor molecules. The cryo-electron microscopy (cryo-EM) structure of these complexes at 3.1 Å resolution confirmed the biochemical data, and allowed the identification of the critical amino acid residues for this interaction, which shows similarities with other DSG2 interacting adenoviruses, despite a low homology in the primary sequences.

Respiratory Carriage of Haemophilus influenzae Associated with Hib Vaccine in Jordanian Children

Abstract Objective Haemophilus influenzae type b (Hib) is the most virulent serotype that colonizes the upper respiratory tract of children. After introducing Hib conjugate vaccine, Hib has become almost entirely replaced by nontypeable H. influenzae (NTHi) strains. This study investigated the incidence of NTHi, which may cause serious sporadic body infections. Methods A total of 300 nasal and throat swab samples were obtained from children aged 6 to 60 months, who visited outpatient pediatric clinics of Jordan University Hospital and Al-Bashir Hospital, Amman, Jordan. Colonies resembling H. influenzae were tested by conventional laboratory tests including Gram staining and antibiotic susceptibility. The 16S rRNA and bexA (capsulation gene) were amplified from the extracted DNA. Swabs (n = 100) were delivered to the laboratory in transport media. After initial culture, DNA was extracted directly and tested by conventional polymerase chain reaction (PCR) employing actin beta primers for assessing the housekeeping gene, followed by quantitative PCR (qPCR) against Hib-specific primers. Results A total of 31/300 (10.33%) of H. influenzae isolates were recovered by culture and confirmed by PCR for 16S rRNA; 96.77% (30/31) were NTHi, and only one isolate was Hib. This isolate was confirmed by detection region II of the cap locus of Hib gene by qualitative TaqMan real-time qPCR. Antibiotic resistance among NTHi to ampicillin and erythromycin was 50.0 and 20.0%, respectively. Conclusion The conjugated Hib vaccine almost eliminated the occurrence of Hib in the upper respiratory tract of the Jordanian children, while NTHi colonization was found in 10% of them.

Capsular serotypes, antimicrobial susceptibility, and the presence of transferable oxazolidinone resistance genes in Streptococcus suis isolated from healthy pigs in China

Streptococcus suis is a pig pathogen and a vector of zoonotic diseases that can cause severe systemic infection in humans. S. suis can colonize the nasal cavity, tonsils, and upper respiratory, genital, and digestive tracts in healthy pigs. Here, to determine prevalence, serotype distribution, and antimicrobial susceptibility of S. suis in healthy pigs, we collected 1813 nasal cavity samples from healthy pigs raised on 17 independent farms in six Chinese provinces between 2016 and 2018. We obtained 223 S. suis isolates (12.3 %) and the antimicrobial susceptibility to a panel of 11 antimicrobial agents was measured by microbroth dilution. Most S. suis isolates (98.7 %) were resistant to at least three classes of antimicrobial agents. The optrA gene conferring resistance to oxazolidinones and phenicols was identified in the chromosome of 27 isolates and on a ∼40-kb plasmid in one isolate; to the best of our knowledge, this was the first report of plasmid-borne optrA gene in S. suis. The genetic environment of optrA showed substantial diversity and could be divided into eleven different types. Interestingly, some fragments of the 89 K pathogenicity island (PAI) were observed together with optrA in 3 isolates, which warrants further attention. Capsular serotypes of S. suis isolates were determined by multiplex PCR. Serotype 29 was the most prevalent, followed by serotype 7 and serotype 2. The presence of highly virulent serotype 2 strains may pose a threat to public health.

Microarray Analysis of Group B Streptococci Causing Invasive Neonatal Early- and Late-onset Infection.

Group B Streptococcus is the leading cause of meningitis and sepsis in newborns. Until now, there is no data of fast and simple typing of group B Streptococcus virulence factors using a genetic microarray and comparing these data to clinical manifestations. A prospective active surveillance study was conducted via 2 independent and nationwide reporting systems, the German Pediatric Surveillance Unit (ESPED) and the Laboratory Sentinel Group at Robert Koch-Institute. Surveillance was performed between 2001 and 2003 and between 2008 and 2010. Typing of virulence factors, serotypes, pilus islands and alpha-like proteins was done by means of a newly developed microarray method. We evaluated 475 isolates of invasive neonatal infections. Predominant virulence factors were serotype III (63%), pilus island 2b and pilus island 1 (50%) and alp rib (64%) (alp - alpha-like protein, rib -resistance to proteases, immunity, group B). There was no significant change over time or geographically within Germany. Serotype III, pilus island 2b + 1 and alp rib showed significant associations with late-onset disease and meningitis, whereas alp 5 had a significant association with early-onset disease. Based on serotypes, pilus islands and alpha-like proteins, it was possible to cluster 86% of all isolates into 5 genetic groups. The molecular epidemiology of a large collection of invasive neonatal infections showed similar distributions, as shown in smaller cohorts before. The microarray used proved to be a fast and reliable technique. Using this new tool, we were able to cluster the isolates according to their virulence factors. The clusters showed a better association with clinical data than single virulence factors.

Virulence Factors and Antimicrobial Resistance Patterns of Non-O157 Shiga Toxin-producing Escherichia coli Isolated from Different Sources at Sadat City

Aims: A great concern directed to non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes due to their public health importance. Detecting the existence, antimicrobial profiles, and virulence repertoire of different STEC serotypes from animals essential for human food are important.&#x0D; Study Design: This study aimed to investigate the presence of STEC in different hosts, the distribution pattern of stx1, stx2, eaeA, and hlyA genes encoding Shiga toxins 1 and 2, intimin, and enterohemolysin, respectively, and the antimicrobial resistance of the detected serotypes.&#x0D; Results: A total of 75 samples were collected, 20 fecal samples from broilers, 15 fecal samples from ducks, 20 beef samples, and 20 human urine samples. Escherichia coli was detected at a rate of 60/75 (80%) distributed as;17 (85%), 8 (53.3%), 15(75%), and 20 (100%) from broilers, ducks, human urine, and beef samples, respectively. There was a significant difference between the isolation rates of E. coli from different sources with p&lt;0.05. The prevalent serotypes were O78, O2:H6, O15:H2, and O26: H1. The frequency of stx1 gene was 56/60 (93.3%), stx2 gene was 55/60 (91.6%), the eaeA gene was 35/60 (58.3%), and hlyA gene was 26/60 (43.3%). The most effective antimicrobials were amoxicillin/clavulanic acid and ampicillin with the efficacy of 52/60 (86.6%) for each, while the efficacy of chloramphenicol and doxycycline was 5/60 (8.3%) and 44/60 (73.3%), respectively.&#x0D; Conclusion: The high frequency of non-O157 Shiga toxin-Producing Escherichia coli from different samples at Sadat City, high prevalence of virulence factors and resistance to chloramphenicol and doxycycline will help in monitoring the distribution of virulent serotypes and contribute to the establishment of control measures to reduce the spread of infection.

Association Between Preterm Birth and Chronic Toxoplasma gondii Infection in Latina Women [04A

INTRODUCTION: Chronic Toxoplasma gondii infects up to one-third of the world's population. Latina women have a higher rate of infection with more virulent serotypes. While acute infection can cause devastating effects in pregnancy, chronic infection had not been considered to have pathological effects. Our objective is to investigate the association between preterm birth and chronic T. gondii infection in Latina women. METHODS: We evaluated 178 Latina women for T. gondii status and followed them through pregnancy and up to 6 weeks postpartum. Demographic information, obstetric histories, pregnancy outcomes, and blood samples were obtained. T. gondii IgG positivity signified chronic exposure. We performed descriptive analyses, chi-square, and Student t-test. RESULTS: There were complete data on 157 Latina women. Thirty-three (21.0%) were T. gondii IgG positive and 124 (79.0%) were T. gondii IgG negative. Among T. gondii positive women, 9 (27.3%) delivered preterm as compared to 15 (12.1%) of T. gondii negative women. There was a significant difference when comparing the frequency of preterm birth in T. gondii IgG positive and T. gondii IgG negative mothers (phi coefficient=.172, P&lt;.031). The mean gestational age of delivery was 36.9 weeks (SD±3.98) for seropositive mothers and 38.1 weeks (SD±2.96) for seronegative mothers (t(155)=1.931, P=.055). CONCLUSION: T. gondii IgG seropositivity was associated with a higher likelihood of preterm delivery in Latina women. Further studies are needed to examine the impact of chronic T. gondii infection on pregnancy outcomes.

Recognition of Lipoproteins by Toll-like Receptor 2 and DNA by the AIM2 Inflammasome Is Responsible for Production of Interleukin-1β by Virulent Suilysin-negative Streptococcus suis Serotype 2.

Streptococcus suis serotype 2 is an important porcine bacterial pathogen and zoonotic agent causing sudden death, septic shock and meningitis. These pathologies are the consequence of an exacerbated inflammatory response composed of various mediators including interleukin (IL)-1β. Elevated levels of the toxin suilysin (SLY) were demonstrated to play a key role in S. suis-induced IL-1β production. However, 95% of serotype 2 strains isolated from diseased pigs in North America, many of which are virulent, do not produce SLY. In this study, we demonstrated that SLY-negative S. suis induces elevated levels of IL-1β in systemic organs, with dendritic cells contributing to this production. SLY-negative S. suis-induced IL-1β production requires MyD88 and TLR2 following recognition of lipoproteins. However, the higher internalization rate of the SLY-negative strain results in intracellularly located DNA being recognized by the AIM2 inflammasome, which promotes IL-1β production. Finally, the role of IL-1 in host survival during the S. suis systemic infection is beneficial and conserved, regardless of SLY production, via modulation of the inflammation required to control bacterial burden. In conclusion, this study demonstrates that SLY is not required for S. suis-induced IL-1β production.