where does the bacteria that causes strep throat come from
Streptococcal pharyngitis Strep throat is caused by group A beta-hemolytic streptococcus (GAS or S. pyogenes).[11] Other bacteria such as non–group A beta-hemolytic streptococci and fusobacterium may also cause pharyngitis.[8][10] It is spread by direct, close contact with an infected person; thus crowding, as may be found in the military and schools, increases the rate of transmission.[10][12] Dried bacteria in dust are not infectious, although moist bacteria on toothbrushes or similar items can persist for up to fifteen days.[10] Contaminated food can result in outbreaks, but this is rare.[10] Of children with no signs or symptoms, 12% carry GAS in their pharynx,[5] and, after treatment, approximately 15% of those remain positive, and are true "carriers".[13]
Helicobacter pylori Helicobacter pylori, previously Campylobacter pylori, is a gram-negative, microaerophilic bacterium found usually in the stomach. It was identified in 1982 by Australian scientists Barry Marshall and Robin Warren, who found that it was present in a person with chronic gastritis and gastric ulcers, conditions not previously believed to have a microbial cause. It is also linked to the development of duodenal ulcers and stomach cancer. However, over 80% of individuals infected with the bacterium are asymptomatic, and it may play an important role in the natural stomach ecology.[7]