Antibiotic Resistance
Rowan Ross
Burnaby North Secondary
Floor Location : M 154 H

Only 100 years ago, bacterial infections were one of the most common causes of death worldwide. Antibiotic-resistant bacteria such as MRSA have become a major threat in hospitals because they are much harder to treat. Antibiotic resistance has been called the next most important problem to modern medicine and by the year 2050 is expected to kill 10 million people annually and have an estimated cost of 100 trillion dollars.



To investigate the frequency of antibiotic-resistant bacteria in our everyday environment, I swabbed and grew the bacteria from fourteen common household and school surfaces, such as doorknobs, cellular phones, and bathroom surfaces. Using the Kirby Bauer method, I tested for antibiotic resistance using three commonly used antibiotics: ampicillin, tetracycline and vancomycin. I found that 100% of the tested surfaces contained bacteria and 92.8% of the tested surfaces contained bacteria that were resistant to at least one of these three antibiotics.



Antibiotic resistance can occur from the overuse and improper dosing of antibiotics. I wanted to determine if, and how quickly, antibiotic resistance could occur if bacteria were given the opportunity. I created bottles of bacterial growth media with increasing concentrations of ampicillin (0, 0.1, 0.3, 1.0, 3.0, 10.0, 30.0, 100, 300, 1000 ug/ml). I progressively exposed a culture of ampicillin-sensitive bacteria, collected from a doorknob, to increasing concentrations of ampicillin. Within 18 days, the bacteria had become resistant to 1000 ug/ml of ampicillin. In contrast, the same antibiotic-sensitive bacteria that had not been given time to evolve could not survive at this concentration. These results showed that bacteria could evolve high resistance to ampicillin within just 18 days.



The improper use of antibiotics has become a major threat to human survival. Common infections with antibiotic-resistant bacteria can lead to a longer duration of illness, increased health care costs, and in some cases, minor injuries can become lethal. The cost of developing a new antibiotic drug can be up to $2.5 billion dollars and takes many years, yet resistance to an antibiotic can evolve in just a few weeks if the drug is used improperly.