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Identification of novel attenuated Salmonella Enteritidis mutants

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Salmonella Enteritidis is a major food-borne pathogen that causes nontyphoidal diarrhoea in humans. Infection of adult egg-laying hens usually results in symptomless carriage but in young chicks it may cause paratyphoid disease. It is not known whether S. Enteritidis requires genes additional to known virulence genes for systemic infection of young chickens. A transposon insertion library was created using S. Enteritidis 10/02, which yielded 1246 mutants. Of 384 mutants screened in chickens for attenuation (30.8% of insertion library), 12 (3.1%) had a 50% lethal dose at least 100 times that of the parental strain. Sequencing revealed insertions in genes involved in the biosynthesis of lipopolysaccharide, cell membrane, ATP biosynthesis, transcriptional regulation of virulence and the yhbC gene, which has an unknown function. Evaluation of in vitro virulence characteristics of a delta yhbC mutant revealed that its ability to invade HeLa cells and survive within a chicken macrophage cell line (HD11) was significantly reduced. It was also less resistant to reactive oxygen and nitrogen intermediates and had a retarded growth rate. Chickens challenged with the delta yhbC mutant cleared the organism from the liver and spleen 1 week faster than the parental strain and were able to develop specific serum IgG antibodies against the delta yhbC mutant.
Jason Chang , Ervinna Pang , Haiqi He , Jimmy Kwang
Salmonella enteritidis , adenosine triphosphate , adults , antibodies , antibody formation , biosynthesis , cell invasion , cell membranes , chicks , diarrhea , food pathogens , gene expression regulation , genes , hens , humans , immunoglobulin G , lethal dose 50 , lipopolysaccharides , liver , macrophages , microbial growth , mutants , nitrogen , oxygen , paratyphoid , pathogen survival , reactive oxygen species , spleen , transposons , virulence
FEMS Immunology and Medical Microbiology 2008 v.53
Journal Articles, USDA Authors, Peer-Reviewed
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