What causes antibiotic resistant bacteria?

Incomplete killing. Mutations in bacteria that lead to resistance can occur when bacteria are exposed to antibiotics in doses that are not strong enough to kill them. The bacteria then can mutate and develop resistance. A favorite professor of mine would always say "dead bacteria can't develop resistance.".
Antibiotics. Bacteria have a great ability to genetically adapt to their environment. After an exposure to a specific antibiotic, a bacterium can modify its genetic makeup to create particular barrier(s). Overuse of antibiotics, inadequate dosing and incomplete dosing can all contribute to the emergence of resistance.

Related Questions

Where do antibiotic resistant bacteria come from?

Various. They evolve in hospitals, sub acute care facilities and skilled nursing facilities. Environments where antibiotics are excessively prescribed and sensitive bacteria are killed off while resistant strains persist and thrive. They also occur in the food supply because of the excessive use of antibiotics in animal husbandry to increase animal growth rates and corporate profits. Read more...

How worried should we be about antibiotic resistant bacteria?

Drug resistance. Very. And it would be very wise for all humans to realize their demand for antibiotics, especially in the winter when most illnesses are viral, are leading to this increasingly worrisome threat. Read more...

Which is more dangerous: bird flu or the growing problem of antibiotic resistant bacteria and why?

Resistance. Bird flu will be rare, albeit theoretically catastrophic with a pandemic that becomes transmissible from human to human. Far more dangerous is the steady growth in resistance of common bacteria that cause the bulk of infections and threaten all of us. Read more...
Both are bad. Bird flu is mutating and will continue to mutate in the future. It is only a matter of time for it to mutate and hopefullly, we will have newer antiviral medications that will be effective against it. Resetant bacteria is also a problem since it is difficult to irradicate these bacteria and they may live in hospitals and other places were susceptible hosts can be harmed. So both are bad challenge. Read more...
At this point, Only a couple of hundred people in the world have died from h5n1 and probably more than that number die daily from drug resistant bugs. At this point, there is no contest. Read more...

Does antibiotic resistant bacteria increase incidence of sepsis?

Can. Bacterial resistance is becoming prevalent as we have increased usage for even non infectious cases. When there is confirmed resistant strain that enters into the blood stream, sepsis is a possibility as we can potentially run out of options to treat. Read more...
Antibiotics/sepsis. Yes. As antibiotics resistance emerges, the severity and duration of bacterial illness is worse, leading to a greater risk of sepsis and adverse events. Read more...
Maybe. It may be more difficult to treat but multidrug resistant bacteria do not necessarily produce more sepsis than very sensitive ones. Read more...