[Study on molecular epidemiology of major pathogenic Streptococcus suis serotypes in middle part of Jiangsu province].
OBJECTIVE
To determine the prevalence of Streptococcus suis and major pathogenic serotypes in middle part of Jiangsu province.


METHODS
Tonsillar specimens from 303 slaughtered pigs aged 6 to 8 months were investigated for the presence of Streptococcus suis and major pathogenic serotypes by polymerase chain reaction (PCR) method. Bacteriological examination compared with molecular genetics identification for three Streptococcus suis isolates were also done.


RESULTS
The overall carrier rate of Streptococcus suis was up to 88.0%, with the percentages of serotype 1(14), 2(1/2), 7 and 9 were 9.6%, 8.5%, 11.3% and 29.5% respectively in 2005. While in 2006, the prevalence of Streptococcus suis was 82.5%, with capsular types 1 (14), 2 (1/2), 7 and 9 were accounted for 17.6%, 2.4%, 25.8% and 20.0% of all the specimens. All the three isolates belonged to Streptococcus suis serotype 2,named 2a, 2f and 14e, which exhibiting the virulent phenotype cps2+/gdh+/mrp-/lepf-/sly-/fbps+/orf2+/89k-, cps2+/lgdh+/mrp-/epf-/sly-/fbps-/orf2-/89k- and cps2+/gdh+/mrp-/epf-/sly-/fbps/orf2-/ respectively. These isolates were all susceptible to amoxicillin, ampicillin, penicillin and resistant to amikacin and tetraycline. Clinical signs were not noted in BALB/c mice and rabbit.


CONCLUSIONS
Prevalence of the Streptococcus suis among the healthy herds in the areas was very high, with various capsule types of Streptococcus suis involved in the same herds, and the virulent phenotype of these 3 isolates were very different from those prevalent Streptococcus suis serotype 2 virulent isolates frequently discovered from the epidemic areas.
Ju
Ai-Ping
AP
Institute of Military Medical Sciences, Nanjing Command, Nanjing 210002, China.
Wang
Chang-Jun
CJ
Zheng
Feng
F
Pan
Xiu-Zhen
XZ
Dong
Ya-Qing
YQ
Ge
Jun-Chao
JC
Lu
Cheng-Ping
CP
Tang
Jia-Qi
JQ
D000583:Amikacin / Q000627:therapeutic use; D000658:Amoxicillin / Q000627:therapeutic use; D000667:Ampicillin / Q000627:therapeutic use; D000818:Animals; D002681:China / Q000453:epidemiology; D051379:Mice; D008807:Mice, Inbred BALB C; D017720:Molecular Epidemiology / Q000379:methods*; D010406:Penicillins / Q000627:therapeutic use; D016133:Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology*; D017011:Streptococcus suis / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity*; D013752:Tetracycline / Q000627:therapeutic use; D014774:Virulence
D010406:Penicillins; D000667:Ampicillin; D000658:Amoxicillin; D000583:Amikacin; D013752:Tetracycline