Prolonged persistence of an epidemic <i>Streptococcus suis</i> strain in a closed pig population

Torremorell, M.; Pijoan, Carlos

doi:10.1136/vr.143.14.394

Cited by 8 publications

(6 citation statements)

References 7 publications

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“…Pulsotype XXIV was the unique or predominant strain in several herds, being repeatedly isolated from different animals during several months or years. These results are consistent with the idea that in a closed population there is a tendency for only one strain to be established and be responsible for all or the majority of clinical cases (17,27) and confirm the ability of certain strains of S. suis to persist during prolonged periods of time in the same herd (27). All these results indicate that, together with the diversity of S. suis strains found in many herds, the existence of a prevalent or of a few prevalent clones responsible for a great proportion of clinical cases is also possible, as has been observed with other pathogens (9,28,29).…”

Section: Discussionsupporting

confidence: 81%

Analysis of Genetic Diversity of Streptococcus suis Clinical Isolates from Pigs in Spain by Pulsed-Field Gel Electrophoresis

et al. 2003

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Pulsed-field gel electrophoresis (PFGE) was used to investigate the diversity of Streptococcus suis isolates of various serotypes recovered from swine clinical samples in Spain. Capsular types 9 (64.9%) and 2 (14.8%) were the most frequently isolated serotypes followed by serotype 7 (5.9%) and serotype 8 (4.3%). The PFGE results of this study with 60 different pulsotypes indicate a great genetic diversity among the S. suis isolates, which is consistent with the broad distribution of S. suis in the swine population. Forty-five percent of the pulsotypes corresponded to single isolates, no pulsotype was common to all farms, and at least 3 different pulsotypes were isolated in 56% of herds in which more than 3 clinical isolates were analyzed. These results reveal a great diversity both between and within herds throughout the strains of S. suis studied, demonstrating that different strains of S. suis are associated with infection in pigs. Some pulsotypes were more frequently isolated and exhibited a wider distribution over herds than others, and were the unique or predominant strains in several herds, suggesting the existence of a prevalent or a few prevalent clones responsible for a large proportion of clinical cases. Overall, the great genetic heterogeneity of the clinical strains of S. suis, the isolation of different strains within the same herd, and the predominance of particular strains in some herds are evidence that infection by S. suis is a dynamic process and reinforce the idea that the epidemiology of S. suis infection is very complex.

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Section: Discussionsupporting

confidence: 81%

Analysis of Genetic Diversity of Streptococcus suis Clinical Isolates from Pigs in Spain by Pulsed-Field Gel Electrophoresis

et al. 2003

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“…Also, the distribution of H. parasuis serovars has been studied in strains isolated mostly from the respiratory tract and mucosal surfaces of healthy piglets, which are probably different from those isolated from systemic sites of sick pigs (19). Recent work done with Streptococcus suis showed that isolates recovered from tonsils of healthy pigs are genetically different from isolates recovered from the brains or joints of infected pigs (21).…”

mentioning

confidence: 99%

Outer Membrane Proteins and DNA Profiles in Strains ofHaemophilus parasuisRecovered from Systemic and Respiratory Sites

Ruiz

Oliveira

Torremorell³

et al. 2001

J Clin Microbiol

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Polyserositis caused by Haemophilus parasuis is an important disease that affects mostly weaned pigs. Recent studies have shown that virulence can differ among strains recovered from distinct body sites and also that it may be related to the presence of certain outer membrane proteins (OMPs). The objective of this study was to compare the OMP and DNA profiles of H. parasuis strains isolated from systemic and respiratory sites from diseased and healthy pigs. Strains evaluated in this study were processed using sodium dodecyl sulfatepolyacrylamide gel electrophoresis and repetitive-PCR techniques. Two experiments were conducted in order to better define the relationship among genotype, phenotype, and site of isolation. Experiment 1 included 53 H. parasuis isolates recovered from healthy and diseased pigs from unrelated herds. Experiment 2 included 31 isolates of H. parasuis obtained from diseased pigs involved in an outbreak in a large, multifarm system. Results showed that strains recovered from systemic sites had more homogeneous OMP and DNA profiles than those isolated from respiratory sites. Evaluation of isolates involved in the multifarm outbreak showed that only two H. parasuis strains were causing disease. These strains had homogeneous OMP and DNA profiles. However, it was noted that these two parameters were unrelated, since strains classified in the same genotype group expressed different OMP profiles. The homogeneity of OMP and DNA profiles of strains isolated from systemic sites strongly suggests the existence of clonal relationships between virulent strains and also suggests that expression of certain OMP profiles may be related to virulence.

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“…The actual early mechanisms used by S. suis to colonize the host are still poorly known. The pathogen may survive in swine tonsils for long periods of time . The tonsillar lymphoid tissue is overlain by mucosal epithelium.…”

Section: Streptococcus Suis Interaction With Mucosal Barriersmentioning

confidence: 99%

Initial steps of the pathogenesis of the infection caused byStreptococcus suis: fighting against nonspecific defenses

et al. 2016

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Edited by Wilhelm JustInteractions between a bacterial pathogen and its potentially susceptible host are initiated with the colonization step. During respiratory/oral infection, the pathogens must compete with the normal microflora, resist defense mechanisms of the local mucosal immunity, and finally reach, adhere, and breach the mucosal epithelial cell barrier in order to induce invasive disease. This is the case during infection by the swine and zoonotic pathogen Streptococcus suis, which is able to counteract mucosal barriers to induce severe meningitis and sepsis in swine and in humans. The initial steps of the pathogenesis of S. suis infection has been a neglected area of research, overshadowed by studies on the systemic and central nervous phases of the disease. In this Review article, we provide for the first time, an exclusive focus on S. suis colonization and the potential mechanisms involved in S. suis establishment at the mucosa, as well as the mechanisms regulating mucosal barrier breakdown. The role of mucosal immunity is also addressed. Finally, we demystify the extensive list of putative adhesins and virulence factors reported to be involved in the initial steps of pathogenesis by S. suis.

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Prolonged persistence of an epidemic Streptococcus suis strain in a closed pig population

Cited by 8 publications

References 7 publications

Analysis of Genetic Diversity of Streptococcus suis Clinical Isolates from Pigs in Spain by Pulsed-Field Gel Electrophoresis

Analysis of Genetic Diversity of Streptococcus suis Clinical Isolates from Pigs in Spain by Pulsed-Field Gel Electrophoresis

Outer Membrane Proteins and DNA Profiles in Strains ofHaemophilus parasuisRecovered from Systemic and Respiratory Sites

Initial steps of the pathogenesis of the infection caused byStreptococcus suis: fighting against nonspecific defenses

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