Streptococcus suis is an important pathogen of pigs and occasionally causes serious human disease. However, little is known about the S. suis population structure, the clonal relationships between strains, the potential of particular clones to cause disease, and the relevance of serotype as a marker for epidemiology. Here we describe a multilocus sequence typing (MLST) scheme for S. suis developed in order to begin to address these issues. Seven housekeeping gene fragments from each of 294 S. suis isolates obtained from various S. suis diseases and from asymptomatic carriage representing 28 serotypes and nine distinct countries of origin were sequenced. Between 32 and 46 alleles per locus were identified, giving the ability to distinguish >1.6 ؋ 10 11 sequence types (STs). However only 92 STs were identified in this study. Of the 92 STs 18 contained multiple isolates, the most common of which, ST1, was identified on 141 occasions from six countries. Assignment of the STs to lineages resulted in 37 being identified as unique and unrelated STs while the remaining 55 were assigned to 10 complexes. ST complexes ST1, ST27, and ST87 dominate the population; while the ST1 complex was strongly associated with isolates from septicemia, meningitis, and arthritis, the ST87 and ST27 complexes were found to contain significantly higher numbers of lung isolates. In agreement with the observed distribution of disease-causing isolates of S. suis, most isolates previously characterized as of high virulence in porcine infection models belong to ST1, while isolates belonging to other STs appear to be less virulent in general. Finally nine STs were found to contain isolates of multiple serotypes, and many isolates belonging to the same serotypes were found to have very disparate genetic backgrounds. As well as highlighting that the serotype can often be a poor indicator of genetic relatedness between S. suis isolates, these findings suggest that capsular genes may be moving horizontally through the S. suis population.

Please cite this article as: Huerta, B., Maldonado, A., Ginel, P.J., Tarradas, C., Gómez-Gascón, L., Astorga, R.J., Luque, I., Risk factors associated with the antimicrobial resistance of staphylococci in canine pyoderma, Veterinary Microbiology (2008Microbiology ( ), doi:10.1016Microbiology ( /j.vetmic.2011 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. peer-00696634, version 1 -13 May 2012 Author manuscript, published in "Veterinary Microbiology 150, 3-4 (2011) 302" DOI : 10.1016/j.vetmic.2011 Page 1 of 19A c c e p t e d M a n u s c r i p t with recurrent pyoderma that had undergone long-term antibiotic treatment (group C). 6Staphylococci were more commonly isolated from the pyoderma-affected than the 7 healthy dogs (p<0.0001). 9Some 78% of the isolates were resistant to at least one antimicrobial agent.

Streptococcus suis is an economically important pathogen of pigs responsible for a variety of diseases including meningitis, septicemia, arthritis, and pneumonia, although little is known about the mechanisms of pathogenesis or virulence factors associated with this organism. Here, we report on the distribution and genetic diversity of the putative virulence factor suilysin, a member of the thiol-activated toxin family of gram-positive bacteria. On the basis of PCR analysis of over 300 isolates of S. suis, the suilysin-encoding gene, sly, was detected in 69.4% of isolates. However, sly was present in a considerably higher proportion of isolates obtained from cases of meningitis, septicemia, and arthritis (>80%) and isolates obtained from asymptomatic tonsillar carriage (>90%) than lung isolates associated with pneumonia (44%). With the exception of serotypes 1, 14, and 1/14, there was no strong correlation between the presence of suilysin and serotype. Analysis of the genetic diversity of suilysin by restriction fragment length polymorphism and sequence analysis found that the suilysin gene, where present, is highly conserved with a maximum of 1.79% diversity at the nucleotide level seen between sly alleles. Assays of hemolytic activity and hybridization analysis provided no evidence for a second member of the thiol-activated toxin family in S. suis. Inverse PCR was used to characterize regions flanking sly, which in turn allowed the first characterization of the equivalent region in a strain lacking sly. Sequence comparison of these regions from sly-positive (P1/7) and sly-negative (DH5) strains indicated that two alternative arrangements are both flanked by genes with highest similarity to haloacid dehalogenase-like hydrolases (5 end) and putative N-acetylmannosamine-6-phosphate epimerases (3 end). However, sly appears to be completely absent from the alternative arrangement, and a gene of unknown function is located in the equivalent position. Finally, PCR analysis of multiple sly-positive and -negative strains indicated that these two alternative genetic arrangements are conserved among many S. suis isolates.Streptococcus suis is an important pathogen associated with a range of diseases in pigs including meningitis, pneumonia, septicemia, and arthritis, although the organism is also frequently carried asymptomatically. The organism has substantial implications for the swine industry in terms of both animal welfare concerns and economic impact. Occasionally, S. suis causes serious zoonotic infections in humans, where it has been associated with septicemia, meningitis, and endocarditis (4, 42). There are currently 35 serotypes of S. suis recognized based on capsular antigens (11-13, 19, 34). Although most clinical disease is associated with only a few of these (notably serotypes 1, 2, and 14), the importance of particular serotypes can vary both geographically and over time (17).Currently, S. suis is controlled largely by the use of prophylactic and therapeutic antibiotics. However, an increase in isolation of...

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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Background: Annotation of protein-coding genes is a key step in sequencing projects. Protein functions are mainly assigned on the basis of the amino acid sequence alone by searching of homologous proteins. However, fully automated annotation processes often lead to wrong prediction of protein functions, and therefore time-intensive manual curation is often essential. Here we describe a fast and reliable way to correct function annotation in sequencing projects, focusing on surface proteomes. We use a proteomics approach, previously proven to be very powerful for identifying new vaccine candidates against Gram-positive pathogens. It consists of shaving the surface of intact cells with two proteases, the specific cleavage-site trypsin and the unspecific proteinase K, followed by LC/MS/MS analysis of the resulting peptides. The identified proteins are contrasted by computational analysis and their sequences are inspected to correct possible errors in function prediction.

A study was made of the biochemical profiles of 59 strains serotyped as Streptococcus suis, isolated from diseased and clinically healthy pigs. The following parameters are proposed for the identification of the species: Voges-Proskauer negativity, hydrolysis of esculin positivity, trehalose positivity, negativity for growth in 6.5% NaCi, and absence of beta-hemolysis on sheep blood agar. S. suis serotype 2 is negative for hippurate, pyrrolidonylarylamidase, and mannose. Streptococcus suis is responsible for a range of clinical processes including meningitis, neonatal septicemia, bronchopneumonia, arthritis, endocarditis, and reproductive disorders, all of which have a negative effect on pig production (2, 4, 6, 10, 11, 14, 16). From an epidemiological viewpoint, S. suis reservoirs appear to be the swine themselves as clinically healthy carriers; the species is readily harbored, primarily in the tonsils and nasal cavities and occasionally in the lungs, vaginas, and prepuces of subjects exhibiting no clinical manifestations (1, 11, 15). Windsor and Elliot (20) differentiated two serotypes of S. suis, 1 and 2, corresponding to the two serogroups previously designated S and R, respectively, by de Moor (9, 11). These two serotypes differ in terms of their capsular antigens (4, 9). Perch et al. (14) identified six new serotypes of S. suis (types 3 to 8) and postulated the existence of others, a hypothesis subsequently borne out by the findings of Gottschalk et al. (5, 7), who characterized a total of 28 serotypes included in Lancefield groups R, S, and T. Serotype 2 is beyond doubt the most important and the most prevalent in swine; it is responsible for substantial losses on pig farms and has thus been the object of most studies dealing with S. suis (1). The biochemical identification of S. suis has been performed with a number of commercial multitest kits such as the Index and API systems (11, 18), in addition to conventional tests including growth and fermentation in phenol red broth containing 0.1% agar and 1% lactose, trehalose, sorbitol, raffinose, or inulin, hydrolysis of hippurate, and sensitivity to optochin (4). Various parameters have been proposed for the biochemical identification of S. suis, including growth in 6.5% NaCl, acetoin production (the Voges-Proskauer [VP] test), and acid production from trehalose and salicin. The VP test is critical and appears to be the most reliable test for differentiating S. suis from S. bovis; it may, however, give rise to false-negative results. The profiles

The inhibitory potential by contact and vapor of basil, cinnamon, clove, peppermint, oregano, rosemary, common thyme, and red thyme essential oils (EOs) against 20 strains of Streptococcus suis was determined by the disk diffusion test. The broth microdilution method was used to determine the minimal inhibitory and minimal bactericidal concentration (MIC and MBC) of the four selected oils. Furthermore, the bactericidal power (ratio MBC/MIC) was calculated. The EOs with the major potential in the disk diffusion method were red thyme, common thyme, oregano, and cinnamon (∅ mean 16.5-34.2 mm), whereas cinnamon did not show vapor activity. In the microdilution test, all the EOs showed notable antimicrobial activity (MIC and MBC 312.5-625 μg·ml ) and a strong bactericidal power (ratio = 1). This is the first study that selects essential oils against S. suis. New studies about the possible synergic effect of EOs with antibiotics and about toxicity and efficacy in in vivo conditions are recommended.