The eight strains isolated from Jiangsu Province in 1998 were also included (six from patients and two from diseased pigs) (Table 1) (9, 15). All of the strains were screened using PCR targeting virulence-associated

genes including MRP (mrp), suilysin (sly) and EF (epf) (16). All of the isolates were also characterized using single enzyme PFGE with SmaI (9) and a MLST scheme (11). The complete genome sequence of five S. suis serotype 2 strains including GZ1 (ST1) (8), SC84 (ST7, NC_012924), 05ZYH33 (ST7) (17), 98HAH12 (ST7) (17), and P1/7 (ST1) (http://www.sanger.ac.uk) were analyzed for potential VNTR loci using TRF, (version 2.02) (18) and the Torin 1 purchase Tandem Repeat Database (http://minisatellites.u-psud.fr/) using alignment parameters as follows: two matches, three mismatches, and five indels

where 50 was the minimum alignment score; 500 bp was the maximum array size of the repeat unit. Where multiple repeat patterns existed in a given locus, the repetitive unit pattern with the highest match rate was selected. To avoid missing a locus where only one copy was in a given sequenced strain whereas multiple repeat copies occur in other strains, selleck kinase inhibitor the TRF output generated from the P1/7, GZ1, SC84, 05ZYH33 and 98HAH12 genomes was compared. Primer Premier 5.0 was used to design the PCR primers targeting the VNTR loci within the flanking regions. Overlapping or adjoining tandem repeats were co-amplified with a single set of primers (19). Strains were cultured on sheep Columbia blood agar plates at 37°C in 5% CO2

for 24 hr. A single isolated colony was inoculated into 5 ml Todd-Hewitt broth and incubated overnight. Total genomic DNA was isolated using QiaAmp DNA isolation columns (Qiagen Gene, Beijing, China) and following the manufacturer’s instructions for Gram-positive bacteria. Standard PCR was performed per the manufacturer’s directions using Taq DNA polymerase (TaKaRa, Beijing, China) in 25 μl reaction mixtures: 2.5 μl buffer (10×), 5 U Taq DNA Tyrosine-protein kinase BLK polymerase, 200 μM each deoxynucleoside triphosphate, 1 μl bacteria genome DNA (10 ng/μl), 0.5 μM each oligonucleotide primer, and RNase-free water. The PCR reaction was performed using a thermal cycle PTC-200 DNA Engine (MJ Search, Beijing, China). The PCR regimen consisted of an initial denaturing at 95°C for 10 min followed by 30 cycles of amplification: 95°C for 1 min, annealing temperature for 1 min, and extension at 72°C for 1 min; with a final extension at 72°C for 10 min. The amplified products (1.5–2.5 μl) were resolved using electrophoresis on a horizontal 1.5% agarose gel (Amplisize, Bio-Rad, Hercules, CA, USA) at a voltage of 6 V/cm for approximately 4 hr using 0.5×TBE buffer (10×TBE is 890 mM Tris base, 890 mM Boric acid, and 20 mM EDTA; pH 8.0). The gels were stained with ethidium bromide (0.