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]
Escherichia coli Escherichia coli (/ˌɛʃɪˈrɪkiə ˈkoʊlaɪ/;[1] also known as E. coli) is a Gram-negative, facultative aerobic, rod-shaped, coliform bacterium of the genus Escherichia that is commonly found in the lower intestine of warm-blooded organisms (endotherms).[2][3] Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in their hosts, and are occasionally responsible for product recalls due to food contamination.[4][5] The harmless strains are part of the normal microbiota of the gut, and can benefit their hosts by producing vitamin K2,[6] and preventing colonization of the intestine with pathogenic bacteria, having a symbiotic relationship.[7][8] E. coli is expelled into the environment within fecal matter. The bacterium grows massively in fresh fecal matter under aerobic conditions for 3 days, but its numbers decline slowly afterwards.[9]