Back To CourseMicrobiology: Tutoring Solution
20 chapters | 340 lessons
As a member, you'll also get unlimited access to over 75,000 lessons in math, English, science, history, and more. Plus, get practice tests, quizzes, and personalized coaching to help you succeed.Try it risk-free
Wendy has taught high school Biology and has a master's degree in education.
Nobody likes getting sick. A sore throat, throbbing head, and aching body are all signs of impending doom. Desperate to feel better, many of us trek to the doctor in hopes of some medicinal relief. In other words, we want antibiotics! These are medicines designed to fight bacterial infections, and they can cure many ailments.
The first antibiotic used by humans was penicillin, and it was discovered quite by accident. A bacteriologist named Alexander Fleming had been studying bacteria in Petri dishes. He left for vacation and did what many of us do in our own homes: left his used dishes sitting in the sink. Most of the Petri dishes were stacked in a tub of Lysol disinfectant to be cleaned later, but a few remained above the liquid.
When Fleming returned from vacation, the Petri dishes of bacteria were, of course, still piled in the sink. As he trudged over to begin the task of cleaning, he noticed something unusual. Mold had grown in some of the Petri dishes that had not been submerged in Lysol. In those dishes with mold, the bacteria was dying. It was clear that this mold, which was found to be the fungus Penicillium, inhibited and killed the bacteria. This would prove to be one of the most crucial breakthroughs of modern medicine.
As we now know, antibiotics are medicines created to fight infection caused by bacteria. The word antibiotic literally means 'against life.' The goal is to kill or stop growth of these tiny infection-causing organisms, known as pathogens. But, how exactly does an antibiotic make this happen?
We've already established that certain fungi are active in fighting infection. But there is another type of microbe that is commonly utilized in antibiotics, and it just so happens that often times, the component in an antibiotic that straps on its boxing gloves to fight off infection is actually another type of bacteria. This type of bacteria is usually found in soil, and examples include Streptomyces and Bacillus.
Now let's look at how the antibiotics actually fight off the infection. Antibiotics are designed to target the pathogens that are making you sick, killing them or stopping their growth. It is microbe against microbe, a battle to the death. But, how do the active components of antibiotics know which cells in your body to attack? In other words, how do they tell bacterial cells and human cells apart? Well, there are many different types of antibiotics, and they attack different kinds of cells in different ways.
A great deal of scientific research has brought about many different types of antibiotics. They often stem from just a few different drugs and are classified based on how they act on pathogens.
One class of antibiotics called beta-lactam zeroes in on a structure unique to bacterial cells. Their main tactic is to target the cell wall, which holds the cell together. Just like a water balloon would certainly break apart if part of the balloon were missing, the same goes for the bacterial cell. As the bacteria builds its cell wall, the components in the antibiotic step in to disrupt this process. Unable to stay intact, the infectious bacteria bursts. Penicillin is an example of an antibiotic that works in this fashion.
Another class of antibiotics called macrolides work by stopping the synthesis of protein by the bacteria. Every cell needs proteins to do work. In this case, the macrolides make it impossible for the proteins in the bacteria to be created. It's like disabling part of the machinery that helps the bacteria work. Without the protein, the bacteria dies.
Still another type of antibiotics called quinolones work by messing up the process of DNA replication in bacteria. Bacteria colonies reproduce and grow by first replicating their genetic information, or DNA. When the bacterial cells attempt to replicate and make a new strand of DNA, quinolones work by breaking the DNA strands. It's like someone knitting the first strand of a scarf, and someone else snipping it before it's finished. Without intact DNA, the bacteria cannot successfully reproduce, and thus, the colony is extinguished.
One more interesting note about antibiotics. You may already know that they are not prescribed for viruses, such as the flu or common cold. But why is this? Viruses are fascinating organisms. What distinguishes them from other microorganisms is the fact that they are not technically alive. You can liken a virus to a zombie. It is essentially a shell that acts like a living creature, but it is not made of cells and has no metabolism. Therefore, there is no way for antibiotics to target viruses as they do bacteria. And so, when your doctor informs you that you have a virus, don't expect a prescription for antibiotics!
There's a wide variety of side effects that can occur as a result of taking antibiotics. Some of the most common are rash, abdominal cramps, nausea, and vomiting. Often times, people are diagnosed with an allergy to a particular medication. In this case, it's important to try a different antibiotic to avoid allergic reactions. Severe reactions, like anaphylaxis and swelling of the face and tongue, are rare but known to occur as well.
One cause of side effects involves the digestive system. When we take antibiotics, we kill not only the bad bacteria but the good bacteria as well. We have millions of microbes inhabiting our bodies constantly. The ones in our gut help break down food molecules and aid in digestion. When we take antibiotics, we kill off many of those helpful bacteria, and so our digestion can become adversely affected. Sometimes, doctors recommend taking probiotics, or foods with good bacteria, during the course of antibiotics. This can help replace the good bacteria in our gut.
Often times, people begin taking a round of antibiotics and then stop before they finish. This is one of the ways our world is creating antibiotic-resistant bacteria. Think about it like this: many bacteria are swimming around competing for food and resources. When a person starts taking an antibiotic, it begins killing the weaker bacteria first. If you stop taking the antibiotic early, the weaker bacteria are dead but the stronger ones remain. They now have less competition for food and resources, and they can multiply more successfully. And, they learn to survive the next time you take the antibiotic. So, when you are prescribed antibiotics, finish them!
Antibiotics are medicines which fight bacterial infection. Utilizing microbes such as fungi and bacteria, antibiotics attack the pathogens in our bodies that make us sick. They accomplish this by breaking the cell wall of the bacteria, disrupting protein synthesis, and dismantling DNA strands of the bacteria. Taking antibiotics can cause side effects such as rash, stomach pain, nausea, and vomiting. Using antibiotics incorrectly can lead to resistant bacteria.
To unlock this lesson you must be a Study.com Member.
Create your account
Already a member? Log InBack
Did you know… We have over 160 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.
To learn more, visit our Earning Credit Page
Not sure what college you want to attend yet? Study.com has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.
Back To CourseMicrobiology: Tutoring Solution
20 chapters | 340 lessons