Which bacteria are most deadly?

You're going to have to think about exactly what you mean by "deadly." WildRockMan is correct about M. tuberculosis. Its prevalence, especially in areas with limited ability to treat those people, makes it a major killer. On the other hand, Yersinia pestis and Bacillus anthracis aren't seen every day, but pulmonary infections with either tend to have very high mortality. In developed western societies, common organisms like E. coli, Strep. pneumoniae, and Staph. aureus cause a lot of minor disease, are generally not that dangerous, but are at the top of the list of infectious diseases causing death again in large part because of their prevalence.

"The most common fatal bacterial diseases are respiratory infections, with tuberculosis alone killing about 2 million people a year, mostly in sub-Saharan Africa." The most deadly is probably Bacillus anthracis with causes Anthrax.

This is highly a function of the host's immune status, so there's really no simple answer.

I would say staphylococcus aureus, because it can cause a septic shock and kill the person. Here more explanation. Staphylococcus aureus can cause a range of illnesses from minor skin infections, such as pimples, impetigo (may also be caused by Streptococcus pyogenes), boils, cellulitis folliculitis, furuncles, carbuncles, scalded skin syndrome and abscesses, to life-threatening diseases, such as pneumonia, meningitis, osteomyelitis endocarditis, Toxic shock syndrome (TSS), and septicemia. Its incidence is from skin, soft tissue, respiratory, bone, joint, endovascular to wound infections. It is still one of the four most common causes of nosocomial infections, often causing postsurgical wound infections. IT CAN BE FOUND. S. aureus may occur as a commensal on human skin (particularly the scalp, armpits, penis and vagina); it also occurs in the nose (in about 25% of the population and throat and less commonly, may be found in the colon and in urine.

There is no way to say which is deadliest, because that depends on what you mean by your question, where you are in the world, etc. I will give you some interesting examples. The deadliest bacteria are usually spread via respiratory droplets, but one bacteria, which causes the most deaths, is found in contaminated water. Vibrio cholera is the bacteria responsible for cholera. It secretes a toxin which causes profuse diarrhea (up to 10 gallons/day), which causes severe dehydration and death to those in developing countries. Mycobacterium tuberculosis is a worldwide problem. In 2005, 8.8 million people fell ill and 1.6 million people died. This is a respiratory disease that can spread to virtually any part of your body and mimic almost any disease. Yersinia pestis is the bacteria responsible for the plague, which wiped out nearly a third of the European population at one time. It is a bacteria that was associated with the ticks that infect rats. When infecting humans, infection of the lungs is the deadliest and the transmissible form of the disease. Today, antibiotics offer a 90% survival rate, but oubreaks have recently occurred in the desert southwest.

As somebody already mentioned, MRSA is a pretty bad bacterial infection. MRSA stands for Methicillin-Resistant Staphylococcus Aureus. What that all means is that the Staphylococcus aureus is resistant to the antibiotic, methicillin, which is used to heal the infection. For a MRSA infection, the only thing we have left for the infection is vancomycin. Vancomycin is pretty much the last resort. However, now there are even some Staphylococcus aureus that are resistant to vancomycin. These are very deadly bacteria because even vancomycin doesn't work for it. Pretty much, we have no antibiotics for it. To prevent these superbugs (bacteria resistant to many antibiotics) from arising, we should be very careful with using antibiotics. We want to avoid misuse of antibiotics. Some ways we can do that is to take antibiotics as the doctor tells us to. Avoid antibacterial soaps and handwashes because soap itself is antibacterial....we don't need to add antibiotics to the soap to make it antibacterial. All that does is give an opportunity to bacteria to develop resistance.

i dont much about bacteria. but i do know about botulism. botulism is a food poisoning and can be found mostly in canned goods, you can tell if the can is dented or under pressure, in or out. it also grows on many other foods, but you really can't tell. just a small bite of it, and, and my science teacher says, "it will kill you dead." very dangerous.. yes. im a hypochrondriac, thats why i know this :)

staph and MRSA are the worst... and they are contracted when u have an cut or wound of some sort and dont keep it clean... MRSA is really bad... its fairly new and they're having a hard time treating it

yo - kara; Botulism isnt a bacteria - it is an oxide of tin metal!