Question

An antibiotic is given repeatedly to treat a recurrent ear infection. It worked initially but now is no longer effective. This indicates that the streotococcus bacterium?

1) Is very sensitive to the antibiotic
2) Is being treated with an infection that has experienced a manufacturing error, making it ineffective
3) Experienced natural selection that has allowed the resistant streotococcus to survive and multiply
4) Is infectious only if it is sensitive to the antibiotic

Answer 1

The antibiotic no longer being effective indicates that the bacteria has developed resistance through natural selection.

Step-by-step explanation:

The fact that the antibiotic initially worked but is no longer effective indicates that the streptococcus bacterium has experienced natural selection, allowing the resistant streptococcus to survive and multiply. Antibiotic resistance occurs when bacteria change in a way that reduces the effectiveness of drugs designed to kill them. The resistant bacteria survive and continue to multiply, causing more harm. This is a result of overuse and incorrect use of antibiotics, which leads to the natural selection of resistant forms of bacteria.