Bacteria+humans=lethal?

There are plenty of bacteria in our bodies but someone told me today that there are some that are actually lethal to humans. My question is where are these bacteria (in the human body) found. And how come they stay there without actually killing us? Why are they there and what purpose they serve (if any)?

Bacteria+humans=lethal?
YES..there are bacteria in the body that are normally there..thus called normal flora. They don't cause any problem UNLESS they increase in number that is no longer okay for the body or they are transferred to a different area that is not their usual habitat. For example, Escherichia coli, a bacteri that is normal in the colon and intestines,it helps a lot in degradation of our wastes (stool). If they are transferred to vagina for instance.. they will be harmful because that is not their place. Thus causing the Urinary tract infection. Lactobacillus is supposed to be living the vaginal area and not E. coli. One more is the Staphlococcus epidermidis which is a normal flora of the skin. But once it has invaded the blood and other sterile fluids of the body (sterile means there MUST be no microorganisms coming outside the body)..and these bacteria increased in number,,thus causing Septicemia which is so fatal in can kill. Hope this helps. God bless!
Reply:E. Coli is in the digestive tract in Humans. It's also possibly lethal when ingested from contaminated meat. I believe there are differing strains so it's not as simple as you might think.





Think of it this way. Too much of a good thing is bad.
Reply:e-coli aids in digestion and is found in your digestive tract. It can also be deadly if it's found in your Jack-In-The-Box. ;)





Just like hydrochloric acid is naturally found in your stomach, but is not so good when you put it in your eyes, I wouldn't worry about it killing you from the inside out because the chances of that happening aren't that great.
Reply:there is bacteria in your body that is actually good





do some research and you might find more
Reply:its impossible to live with out bacteria, but it can hurt us to live with it too... you decide
Reply:Each bacteria (the safe ones that live in you) can kill you if they move to another area. If the bacteria that digests your food gets into your blood stream, they will kill you.





The reason that we have bacteria in us is to break down food. Our bodies can't digest food directly. What we absorb is bacteria ****. I know that there are others, but I'm not sure where or what they do.
Reply:Most of the harmful bacteria are in the gut. As long as they stay there, no problem, but if they enter the blood stream they can attack organs that have no built in defense to the little critters. For instance there is a type of bacteria that lives in our mouths that causes no problems there but during dental procedures they can enter the blood stream and the immune system has to deal with them. This can be especially dangerous to someone with a damaged or repaired heart as they tend to colonize the heart valves. Often with fatal results. Fortunately a course of antibiotics prior to the dental work solves the problem.





That is just one example, I'm sure there are many more.