Taxonomy

The genus name ''Salmonella'' is derived from Dr. D. E. Salmone, who first isolated Salmonella choleraesuis from porcine intestine. The nomenclature and classification of Salmonella have changed many times over the past century and still are not entirely stabilized. The classification has divided Salmonella into two species, S. enterica and S. bongori.[1] The S. enterica can be classified into six subspecies by its biochemical characteristics and host range (Table 1). Almost all serotypes pathogenic to humans belong to the subspecies enterica. The genus Salmonella is extremely polymorphic. Members of the seven Salmonella subgroups have been classified into over 2300 serovars according to somatic O, capsular Vi, and flagellar H antigens.[2] Differences within Salmonella serovars are based on those of the surface antigen such as O and H antigens. The O antigens are derived from polysaccharide domains of lipopolysaccharides (LPS) in the cell wall and the H antigens are derived from flagellin proteins in the flagella. O and H antigens are used for identification of Salmonella serovars by agglutination tests with O and H antigen specific antisera, and Salmonella serovars are determined by the combination of O and phase 1 and 2 H antigen type. Different S. enterica serovars produce different disease syndromes and show host specificities according to their antigenic profiles (Table 2). Therefore, it is necessary and important to differentiate Salmonella serovars from one another to ensure that each pathogen and its epidemiology are correctly recognized.

Major human pathogenic serovars include serovars Typhi, Paratyphi A, Shottmuelleri (Paratyphi B), Hirsch-feldii (Paratyphi C), and Sendai. These serovars are almost always pathogens only of humans. The clinically important serovars, serovar Typhi and Paratyphi A, which are pathogens only of humans, cause enteric fever. The remaining serotypes of salmonellae are broadly spread into the animal kingdom. Salmonella has been isolated from all species, including mammals, poultry, birds, reptiles, amphibians, and insects. Human salmonella infections are generally caused by ingestion of contaminated food that is made from animal products, such as eggs and meat. S. Typhimurium and S. Enteritidis are the most frequently isolated serovars from foodborne outbreaks worldwide.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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