Hybridization analysis of the gene encoding a hemolysin (suilysin) of Streptococcus suis type 2: evidence for the absence of the gene in some isolates

Okwumabua, Ogi

doi:10.1016/s0378-1097(99)00522-4

Cited by 15 publications

(23 citation statements)

References 19 publications

(26 reference statements)

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“…A gene encoding suilysin (sly) has been cloned and sequenced (30), and the absence of sly in some S. suis strains was demonstrated by PCR using different sets of primers and/or by Southern hybridization analysis using cloned or amplified sly as a probe (24,30). In this study, using 40 field isolates and 28 serotype reference strains, we analyzed the sly region and the corresponding chromosomal region of the strains lacking sly in order to provide additional knowledge about the acquisition and intraspecies transfer of genes in this bacterium.…”

mentioning

confidence: 99%

Evidence for Lateral Transfer of the Suilysin Gene Region of Streptococcus suis

2002

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Suilysin is a cholesterol-binding cytolysin encoded by sly in Streptococcus suis. DNA sequence determination of the sly locus in a strain lacking sly revealed the presence of another gene, designated orf102, in the place of sly. No transposable element or long-repeat sequence was found in the close vicinity. Except for six strains whose corresponding loci have been rearranged, all of the remaining 62 strains examined had either sly or orf102 at the same locus and their flanking regions were conserved. The genetic organizations having either sly or orf102 were found in the strains whose 16S rRNA sequences were identical. These results suggest that S. suis acquired sly or orf102 from a foreign source and that these genes subsequently spread among S. suis strains by homologous recombination.

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confidence: 99%

Evidence for Lateral Transfer of the Suilysin Gene Region of Streptococcus suis

2002

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“…However, the absence of these proteins in some virulent strains may preclude the routine use of these tests. Moreover, in a previous study we showed that these proteins were present neither in all S. suis strains nor in all virulent European strains (5,19 20). This method was very attractive, but it was only applied to detect or characterize S. suis from pure cultures.…”

Section: Discussionmentioning

confidence: 99%

“…This serotype was also isolated from nursery pigs with serious cases of meningitis on a Canadian farm (9). Some S. suis strains isolated from healthy carrier pigs (particularly in ton- (19,30). However, the absence of these proteins in some virulent strains may preclude the routine use of these tests.…”

Section: Discussionmentioning

confidence: 99%

Multiplex PCR Assay for Detection of Streptococcus suis Species and Serotypes 2 and 1/2 in Tonsils of Live and Dead Pigs

Marois¹,

Bougeard

Gottschalk

et al. 2004

J Clin Microbiol

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A PCR assay was developed for the detection of Streptococcus suis serotypes 2 and 1/2. This multiplex PCR is based on the amplification of the gene coding for 16S rRNA of S. suis and on the amplification of the cps2J gene coding for the capsule of S. suis serotypes 2 and 1/2. An internal control was constructed and added in this test to monitor the efficiency of amplification in each reaction. To evaluate the specificity of the test, 31 strains of other bacterial species related to S. suis or isolated from pigs and 42 strains of S. suis serotypes 1 and 3 to 34 were analyzed. The detection threshold of the test was 28 S. suis CFU/ml. The specificity and the sensitivity of the multiplex PCR test and the presence of an internal control allowed the analysis of biological samples without a culture step. The PCR assay was then applied to the detection of 14 S. suis serotype 1/2 strains, 88 S. suis serotype 2 strains isolated from pigs, and 25 S. suis serotype 2 strains isolated from humans. This test was also applied to analyze tonsil samples of pigs experimentally infected and carrier pigs without any symptoms.

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“…The strains were screened for the presence of the suilysin gene (sly) essentially as described previously (12).…”

Section: Methodsmentioning

confidence: 99%

Differentiation of Highly Virulent Strains of Streptococcus suis Serotype 2 According to Glutamate Dehydrogenase Electrophoretic and Sequence Type

Kutz¹,

Okwumabua

2008

J Clin Microbiol

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The glutamate dehydrogenase (GDH) enzymes of 19 Streptococcus suis serotype 2 strains, consisting of 18 swine isolates and 1 human clinical isolate from a geographically varied collection, were analyzed by activity staining on a nondenaturing gel. All seven (100%) of the highly virulent strains tested produced an electrophoretic type (ET) distinct from those of moderately virulent and nonvirulent strains. By PCR and nucleotide sequence determination, the gdh genes of the 19 strains and of 2 highly virulent strains involved in recent Chinese outbreaks yielded a 1,820-bp fragment containing an open reading frame of 1,344 nucleotides, which encodes a protein of 448 amino acid residues with a calculated molecular mass of approximately 49 kDa. The nucleotide sequences contained base pair differences, but most were silent. Cluster analysis of the deduced amino acid sequences separated the isolates into three groups. Group I (ETI) consisted of the seven highly virulent isolates and the two Chinese outbreak strains, containing Ala 299 -to-Ser, Glu 305 -to-Lys, and Glu 330 -to-Lys amino acid substitutions compared with groups II and III (ETII). Groups II and III consisted of moderately virulent and nonvirulent strains, which are separated from each other by Tyr 72 -to-Asp and Thr 296 -to-Ala substitutions. Gene exchange studies resulted in the change of ETI to ETII and vice versa. A spectrophotometric activity assay for GDH did not show significant differences between the groups. These results suggest that the GDH ETs and sequence types may serve as useful markers in predicting the pathogenic behavior of strains of this serotype and that the molecular basis for the observed differences in the ETs was amino acid substitutions and not deletion, insertion, or processing uniqueness.Streptococcus suis is a world-wide pathogen of swine and an important zoonotic agent (21,22,24,26,27). Strains of this bacterium are divided into 35 serotypes (types 1/2 and 1 through 34) according to polysaccharide capsular antigens. Type 2 is the type most frequently associated with disease and also the type most often isolated. The disease conditions in swine include meningitis, arthritis, septicemia, endocarditis, encephalitis, abortions, polyserositis, and bronchopneumonia (22). S. suis has been isolated from other animal species, including horses, dogs, cats, birds, and wild boars, suggesting that it may be pathogenic for more than one animal species (22). In infected humans, S. suis type 2 can cause meningitis, endocarditis, septicemia, toxic shock, and permanent hearing loss (21,22,24,26,27). A recent outbreak in China, which involved 39 human and Ͼ200 swine deaths, has caused elevated concern (27). Attempts to effectively control S. suis infection have been problematic due to genetic heterogeneity within and between serotypes, a lack of effective vaccine and diagnostic reagents, inability to effectively distinguish virulent from nonvirulent isolates, a paucity of information on the genetics of S. suis relative to its mechanism of pathogen...

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Hybridization analysis of the gene encoding a hemolysin (suilysin) of Streptococcus suis type 2: evidence for the absence of the gene in some isolates

Cited by 15 publications

References 19 publications

Evidence for Lateral Transfer of the Suilysin Gene Region of Streptococcus suis

Evidence for Lateral Transfer of the Suilysin Gene Region of Streptococcus suis

Multiplex PCR Assay for Detection of Streptococcus suis Species and Serotypes 2 and 1/2 in Tonsils of Live and Dead Pigs

Differentiation of Highly Virulent Strains of Streptococcus suis Serotype 2 According to Glutamate Dehydrogenase Electrophoretic and Sequence Type

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