[Characteristics of Salmonella enterica serovar Senftenberg lacking Salmonella pathogenicity island 1].
OBJECTIVE
To study the characteristics of the strains of Salmonella enterica (S. enterica) serovar Senftenberg lacking Salmonella pathogenicity island 1 (SPI-1).


METHODS
A total of 10 strains of S. enterica serovar Senftenberg were isolated from 10 cases of diarrhea patients. Pulsed field gel electrophoresis (PFGE), PCR, sequencing techniques and cell invasion test were adapted to study the molecular types and invasiveness of the genes and cells; and made a comparison between the 10 strains and the strains (C02013) isolated in Shenzhen in 2002.


RESULTS
The 10 Senftenberg isolated (S09007-S09012, S09014-S09017) in Shanghai showed three PFGE patterns, which were significantly different from the strains isolated in Shenzhen. PCR-amplified results indicated the invasion gene (invA), secreted effector protein gene (sipA) and gene fragments as fhlA-hilA, hilA-spaP and spaP-invH in the 10 strains of SPI-1 were all negative. The sequencing results revealed that the 10 strains isolated in Shanghai lacked most parts of SPI-1 genes, as fragments from orgA to invH and parts of orgA gene itself; however, compared with strains isolated in Shenzhen, the sprB-orgC gene existed. The missing parts of genes were replaced by a simple insertion sequence (IS) of 1000 bp in the strains isolated both in Shenzhen in 2002 and in Shanghai in 2006. The invasiveness rates of the 10 strains (S09007-S09012, S09014-S09017) towards Hela cells were (0.0053 ± 0.0024)%, (0.0046 ± 0.0006)%, (0.0047 ± 0.0003)%, (0.0064 ± 0.0012)%, (0.0065 ± 0.0011)%, (0.0070 ± 0.0020)%, (0.0115 ± 0.0030)%, (0.0099 ± 0.0039)%, (0.0180 ± 0.0135)% and (0.0031 ± 0.0012)%, respectively; which were all significantly lower than the rate of invA-positive control strain STM1344 ((5.0800 ± 0.6333)%); lower or close to the rate of invA-lacked artificial-mutated strain STMinvA-((0.0193 ± 0.0045)%).


CONCLUSIONS
SPI-1 genes are not essential for the diarrhea caused by S. enterica serovar Senftenberg.
Microbiology Department of Shenzhen Centre for Disease Control and Prevention, Shenzhen 518055, China.
Ying-hui
YH
Li
Xue-bin
XB
Xu
Qing-hua
QH
Hu
Xiao-lu
XL
Shi
Yi-man
YM
Lin
Ya-qun
YQ
Qiu
D000328:Adult; D000368:Aged; D015373:Bacterial Typing Techniques; D003967:Diarrhea / Q000382:microbiology*; D005243:Feces / Q000382:microbiology*; D005260:Female; D005798:Genes, Bacterial; D044404:Genomic Islands; D006367:HeLa Cells; D006801:Humans; D008297:Male; D008875:Middle Aged; D019779:Salmonella enterica / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity