State the similarity between Shigella and Salmonella
There are many points of similarity between Shigella and Salmonella. They dwell primarily in the gastrointestinal tract, with optimum temperature of 37ºC, grow both aerobically and anaerobically they grow freely in warm, bland, moist foods. But unlike salmonellae, the shigellae have no flagella and thus are non-motile. The species involved are Shigella sonnei, S. ysenteriae, S. flexineri and S. boydii. As few as 10cfu of S. dysenteriae are known to initiate infection in susceptible individuals. The organisms tolerate salt concentration of 5-6% and are relatively heat sensitive.