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Streptococcus suis is an important swine and human pathogen. Inflammation, a hallmark of S. suis infection, is thought to be responsible for most clinical signs of meningitis, septicaemia and sudden death. In this work, using a porcine whole blood model, S. suis serotype 2 was shown to trigger the release of several pro-inflammatory cytokines as evaluated by reverse transcriptase-PCR and enzyme-linked immunosorbent assay. Although individual variations were observed among different S. suis strains, no correlations were observed between the strain origin/phenotype and cytokine levels. Live bacteria induced higher tumour necrosis factor alpha, interleukin-1 beta (IL-1β) and IL-6 levels than did heat-killed bacteria. In contrast, heat-killed bacteria stimulated higher levels of IL-8 and monocyte chemotactic protein one (MCP-1). The bacterial cell wall was observed to be the major cytokine-inducting components, whereas capsule expression was important for MCP-1 activation. The presence of specific antibodies suppressed bacterial growth resulting in significantly reduced levels of cytokine production. Thus, antibody-mediated bacterial phagocytosis combined with suppressed inflammation may be beneficial for infection control strategies. We provide first evidence of S.suis-induction of pro-inflammatory swine cytokines and demonstrate the strength and relevance of the whole blood culture systems in the investigation of S. suis modulation of cytokine production. [ABSTRACT FROM AUTHOR]

Abstract: Streptococcus suis serotype 2 is a major swine and human pathogen that causes septicemia and meningitis. The ability of S. suis serotype 2 to bind to different extracellular matrix (ECM) proteins was evaluated by ELISA. All 23 strains tested bound to plasma and cellular fibronectin and collagen types I, III, and V, some to fibrin, vitronectin, and laminin, and none to the other ECM proteins tested. An unencapsulated isogenic mutant bound to ECM proteins better than its parental encapsulated strain, suggesting that the polysaccharide capsule interfered with binding. Cross-inhibition was observed between soluble plasma fibronectin and collagens in the ECM adherence assay, indicating that binding domains for both proteins exist on the same or nearby bacterial surface molecules. On the other hand, pre-incubation with plasma fibronectin increased binding to collagen IV, suggesting that S. suis might use fibronectin as a bridging molecule. The results of heat treatment and proteolytic digestion suggest that adhesins for these ECM proteins are proteinaceous in nature. [Copyright &y& Elsevier]

The article discusses the distribution of Streptococcus suis from 2012 to 2014 and Actinobacillus pleuropneumoniae from 2011 to 2014 serotypes. It states that most isolates originated from the Diagnostic Service of the Faculty of Veterinary Medicine on Université de Montréal. The serotypes were isolated from diseased pigs.

Streptococcus suis is one of the most important swine bacterial pathogens causing economic losses. This report presents the serotype distribution of S. suis recovered from diseased pigs in Québec from January 2015 to June 2020. Serotypes 1/2 and 2 predominated, followed by serotypes 7, 3, 5, 4, 9, 1, and 14. Compared to previously reported data, very few changes could be observed concerning the serotype distribution, indicating a relative stability. Half of the untypable isolates did not belong to the species S. suis sensu stricto , as determined by recN polymerase chain reaction. Less than 10% of "real S. suis " isolates were untypable. The genetic diversity of S. suis serotypes 1, 2, and 14, as analyzed by multilocus sequence typing, was mainly represented by sequence type (ST)1, ST28, ST25, and ST94. All ST1 isolates (considered highly virulent) belonged to either serotype 1 or 14., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

We report here the complete genome sequence of the widely studied Actinobacillus pleuropneumoniae serovar 8 reference strain 405, generated using the Pacific Biosciences (PacBio) RS II platform. Furthermore, we compared draft sequences generated by Illumina sequencing of six stocks of this strain, including the same original stock used to generate the PacBio sequence, held in different countries and found little genetic variation, with only three SNPs identified, all within the degS gene. However, sequences of two small plasmids, pARD3079 and p405tetH, detected by Illumina sequencing of the draft genomes were not identified in the PacBio sequence of the reference strain.

Actinobacillus pleuropneumoniae (APP), the causative agent of porcine pleuropneumonia, is highly contagious and responsible for high morbidity, mortality, and economic losses in the swine industry worldwide, but quick serotyping and diagnosis are still not widely available. In this study, we sought to validate the use of Whatman FTA ® cards for collection and processing of A. pleuropneumoniae isolates, or porcine lung tissue samples, for direct use in diagnostic multiplex PCRs. We have optimized the processing of 3-mm discs punched from FTA ® cards loaded with cultured A. pleuropneumoniae , or imprinted on lesioned regions of lung tissue, with only three distilled water washes before addition into our APP-multiplex PCR (mPCR) assay for rapid, low-cost identification and serotyping. DNA captured on FTA ® cards generated the same diagnostic PCR results as DNA extracted using commercial kits for 85 A. pleuropneumoniae clinical isolate cultures and 22 lung samples. Additionally, bacterial DNA bound to FTA ® cards was detectable by PCR after 6 months of storage at 37°C. This study provides simple, efficient, rapid, and practical sample processing for detection and molecular serotyping of A. pleuropneumoniae ., Competing Interests: EV and PP are employed by Ceva Animal Health Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Stringer, Bossé, Lacouture, Gottschalk, Fodor, Angen, Velazquez, Penny, Lei, Langford and Li.)

Actinobacillus pleuropneumoniae serotype 17, one of the two most recent serotypes described, has been isolated from diseased pigs in North America. Yet, no serological test for surveillance has been developed so far. An enzyme-linked immunosorbent assay (ELISA) using the long-chain lipopolysaccharide antigen (LC-LPS) of this serotype is described. As predicted by previous genetic data on the O-antigen locus, cross reactions were observed between this serotype and serotypes 3, 6, 8, and 15. Although animals infected by serotype 17 would be detected using the current serotype 3 LC-LPS ELISA, better results may be obtained when plates are coated with the antigen purified from the homologous serotype., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Problems with serological cross-reactivity have led to development of a number of PCRs (individual and multiplex) for molecular typing of Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia. Most of these assays were developed for detection of specific amplicons within capsule biosynthetic genes before the availability of complete sequences for the different serovars. Here we describe comparative analysis of the complete capsular loci for all 18 serovars of A. pleuropneumoniae, and development of two multiplex PCRs for comprehensive capsule typing of this important pig pathogen., (Copyright © 2018. Published by Elsevier B.V.)

The aim of this study was to investigate isolates of Actinobacillus pleuropneumoniae previously designated serologically either as non-typable (NT) or as 'K2:07', which did not produce serovar-specific amplicons in PCR assays. We used whole genome sequencing to identify the capsule (CPS) loci of six previously designated biovar 1 NT and two biovar 1 'K2:O7' isolates of A. pleuropneumoniae from Denmark, as well as a recent biovar 2 NT isolate from Canada. All of the NT isolates have the same six-gene type I CPS locus, sharing common cpsABC genes with serovars 2, 3, 6, 7, 8, 9, 11 and 13. The two 'K2:O7' isolates contain a unique three-gene type II CPS locus, having a cpsA gene similar to that of serovars 1, 4, 12, 14 and 15. The previously NT isolates share the same O-antigen genes, found between erpA and rpsU, as serovars 3, 6, 8, and 15. Whereas the 'K2:O7' isolates, have the same O-antigen genes as serovar 7, which likely contributed to their previous mis-identification. All of the NT and 'K2:O7' isolates have only the genes required for production of ApxII (apxIICA structural genes, and apxIBD export genes). Rabbit polyclonal antisera raised against representative isolates with these new CPS loci demonstrated distinct reactivity compared to the 16 known serovars. The serological and genomic results indicate that the isolates constitute new serovars 17 (previously NT) and 18 (previously 'K2:O7'). Primers designed for amplification of specific serovar 17 and 18 sequences for molecular diagnostics will facilitate epidemiological tracking of these two new serovars of A. pleuropneumoniae., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)

The characteristics of 29 Chilean field strains of Streptococcus suis recovered between 2007 and 2011 from pigs with clinical signs at different farms were studied. Serotyping with use of the coagglutination test revealed that all but 1 strain belonged to serotype 6; the remaining strain was serotype 22. All the serotype-6 strains were suilysin (hemolysin)-negative; in addition, they were found to be genotypically homogeneous by enterobacterial repetitive intergenic consensus sequence-based polymerase chain reaction (ERIC-PCR) and sensitive to ampicillin, ceftiofur, penicillin, and trimethoprim/sulfamethoxazole. The results indicate that, in contrast to what is generally observed in other countries, a single clone of S. suis was isolated from diseased pigs in the central region of Chile.

Streptococcus suis is an important pathogen in the swine industry. This article is the first to report the occurrence, risk factors, serotype distribution, and antimicrobial susceptibility of S. suis recovered from employees and environmental samples of swine slaughterhouses in Brazil. Tonsillar swabs from all 139 pig-slaughtering employees and 261 environmental swabs were collected for detection of S. suis and serotyping by monoplex and multiplex polymerase chain reaction, respectively. Antimicrobial susceptibility was determined by the disk-diffusion method. Although S. suis was not detected in any of the tested employees, it was isolated from 25% of the environmental samples. Significant differences (P < 0.05) in the occurrence of S. suis were observed between slaughterhouses and between areas of low, medium, and high risk. The most frequent serotypes were 4 and 29, each accounting for 12% of the isolates, followed by 5, 12, 21, and 31, each accounting for 6%. High rates of susceptibility to the antimicrobials doxycycline (100%), ceftiofur (94%), ampicillin (81%), and cephalexin (75%) were observed. However, multidrug resistance was observed in all the isolates. Because S. suis is present in the environment of swine slaughterhouses, on carcasses and knives, as well as on the hands of employees in all areas, all employees are at risk of infection.

Feral swine (Sus scrofa) are widely distributed in the United States. In 2011 and 2012, serum samples and tonsils were recovered from 162 and 37 feral swine, respectively, in the US to evaluate exposure to important swine endemic pathogens. Antibodies against porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) were found in 2.5% and 25.3% of tested sera, respectively. Positive serological reactions against Mycoplasma hyopneumoniae and Actinobacillus pleuropneumoniae have been detected in 19.7% and 69.7% of animals. More than 15% of animals presented antibodies against these 2 pathogens simultaneously. Most animals were also seropositive for Lawsonia intracellularis. Feral swine can also be involved in transmission of zoonotic agents. Almost 50% of animals possessed antibodies against Salmonella. In addition, 94.4% of animals were carriers of Streptococcus suis in their tonsils. In conclusion, feral swine may be considered as a potential reservoir for different endemic diseases in domestic pigs, as well as for important zoonotic agents.

The aim of this study was to compare, by randomly amplified polymorphic DNA (RAPD), the diversity of Streptococcus suis serotypes 1/2 and 2 isolates recovered at slaughter houses from the tonsils of clinically healthy pigs. The pigs belonged to herds with or without clinical signs of S. suis disease. Overall, a low diversity was observed among isolates of serotype 1/2. A representative isolate recovered from a diseased animal presented a relatively high similarity (85%), with most isolates recovered from carrier pigs, from herds either with or without clinical signs of S. suis disease. For serotype 2 isolates, a relatively high degree of heterogeneity was observed in the whole population. Two subpopulations were observed for serotype 2 isolates, which arose from herds with clinical signs. Interestingly, the representative isolate coming from the diseased pig was included in a small closed cluster, with 2 isolates recovered from carrier pigs belonging to the same herd. On the other hand, most of the S. suis serotype 2 isolates originating from herds with no history of S. suis disease, were closely related (90% similarity). Furthermore, they presented different RAPD patterns from those originating from animals from the herd presenting S. suis clinical signs due to this serotype. Results suggest that, in the herds studied, clinical manifestations due to serotype 2 are probably related to the virulence of a specific isolate. Conversely, for the herd affected with serotype 1/2, clinical manifestations of the disease were more likely to be the result of inherent herd factors than the virulence of the specific isolate.