antibiotics are very commonly used medications and they have been an incredible tool for curing infectious diseases and saving lives but there are also some potential negative consequences that can come with taking antibiotics some of which can be quite serious so in today's video we're going to talk about how antibiotics work the good things they can do for the human body but also some of those potential negative effects and of course we'll discuss some concerns around their future use and antibiotic resistance it's definitely going to be a fun one so let's do this so what are antibiotics and how do they work antibiotics are substances that kill or inhibit the growth of bacteria and one of the coolest and Most Fascinating Concepts that I remember learning about as a microbiology student and this concept's very important to how antibiotics actually work is something called selective toxicity we want these antibiotics to be selectively toxic meaning we want them to be harmful to the bacteria but not to our own human cells and this is accomplished by exploiting the differences between the metabolism and the structure of the bacteria versus our own human cells and there are some major differences between bacteria and our cells for example bacteria have a cell wall our cells do not bacteria also have some major differences in their ribosomes and their nucleic acids like DNA and also some subtle differences in their cell membrane remember a cell membrane is different than a cell wall and antibiotics do a pretty good job at exploiting or targeting these differences so let's give some examples of how antibiotics work to exploit some of these differences and then we can discuss some of the good things that antibiotics do for the human body as well as some concerns or considerations with taking them and as we get into how antibiotics work it's also useful to know that antibiotics can be bacterio cdal or bacteriostatic a bacterio cidal antibiotic will actually kill the bacteria whereas a bacteriostatic antibiotic will slow or inhibit the growth of the bacteria so if someone were taking a BAC ostatic antibiotic they'd also need their immune system to come in and help with the killing because if you remove that bacteriostatic antibiotic the bacteria could start growing again but both bacterio cdal and bacteriostatic antibiotics have been used successfully to treat multiple different types of infections some of the most common antibiotics that you've likely heard of work to kill bacteria by inhibiting the synthesis of their cell wall which is pretty easy to exploit because human cells don't have a cell wall and if the bacteria cannot link certain compon on of their cell wall together during cell division water will rush in causing the bacterial cell to rupture and die and like I said some of the most common antibiotics work this way the betalactams now you may not have heard of them as called the betalactams but you've likely heard of the penicillin and maybe even the sephos sporin a very common penicillin is like something like a moxacin maybe you've even heard of a seyos sporin that's commonly used like seex and also known as Keflex there are also multiple antibiotics that work to inhibit protein synthesis of bacteria without interfering with the protein synthesis in human cells now you may have heard me mention ribosomes earlier on and if you've taken a biology class you may remember that ribosomes are these cool structures inside the cells that help build proteins and again the ribosomes and bacteria are different enough from the ribosomes and human cells that they are a great Target for these antibiotics and if you interfere with the protein synthesis of the bacteria that could slow the growth or even potentially kill the bacteria and there are multiple different classes of antibiotics that work to inhibit some portion of the ribosome or some step in this protein synthesis and I'll give you an example of an antibiotic from each of the major classes maybe you've heard of neomin doxycycl is from another class isomyosin from another and maybe You' even heard of chloromycin some antibiotics work to inhibit or block certain steps in the process of bacterial DNA synthesis and I know I sound like a little bit of a broken record but there are differences in how bacteria synthesize DNA versus how human cells synthesize DNA so again another potential difference to to exploit now if a bacterial cell can't properly synthesize its DNA probably not going to be a big surprise that that could slow its growth or even potentially kill the bacterial cell and there are again multiple antibiotic examples that work in this way maybe you've heard of Baum another antibiotic from a different class that you may have also heard about is called cyprol flasin now I did mention earlier that there are some small differences between the cell membranes of bacteria versus the cell membranes of human cells but not a lot of differences and therefore there aren't very many an biotics that work to disrupt the cell membrane of bacteria there are a few maybe you've heard of the polymixin or maybe even daptomycin but again wouldn't be shocked if you haven't heard of those because again not very many antibiotics work in this way but now that we know the main ways that antibiotics can actually kill or slow the growth of bacteria how can they help the human body it probably isn't going to come as a surprise the main benefit of antibiotics is to treat infections that the body couldn't fight off or would have trouble fighting off on its own but let's be sure to give antibiotics their credit here the discovery and use of antibiotics is arguably one of the most important medical contributions of the 20th century antibiotics have helped to increase the average human life expectancy and have saved a countless number of lives that would otherwise have been shortened due to infection however sometimes us humans have a little bit of a hard time containing ourselves and can use too much of a good thing because antibiotics are definitely overused to treat certain conditions or infections that shouldn't require the use of an antibiotic and remember that selective toxicity principle even though antibiotics were not designed to directly Target specific structures of our own cells to kill them or inhibit their growth that doesn't mean they can't come with some side effects potential allergic reactions or even some level of toxicity with certain concentrations of the drug and let's go back to that idea of using them too much misuse or overuse of antibiotics have contrib attributed to bacteria developing resistance to certain antibiotics making it more difficult to treat certain infections so let's give some examples of some potential side effects and even some potential harm that can occur with antibiotic use and then of course we'll finish up with antibiotic resistance and some of the most common set of side effects that can occur with almost any antibiotic are GI symptoms upset stomach nausea and of course that wonderful diarrhea sometimes referred to as antibiotic Associated Di diarrhea now luckily for most people this is more of a temporary annoyance and the diarrhea will improve and things will go back to normal after the antibiotic course is completed now there are some people where the diarrhea can get bad enough where they may need to consider changing to a different antibiotic and one of the reasons why antibiotic Associated diarrhea is thought to occur is due to this use of a broad spectrum antibiotic broadspectrum antibiotic is an antibiotic that has activity against multiple different types of BAC bacteria so yes it would kill the pathogen that's causing the infection but could also kill and disrupt the bacteria that normally reside within your gut often referred to as the normal flora but again this is often a temporary disruption for most people and the normal flora can recover however there are some people that are a bit more unfortunate and can get things that are worse than the typical antibiotic Associated diarrhea they can get a secondary infection due to suppression of the normal flora one of those is clostridium defil infection often referred to as SEI now those that are colonized with SEI in their colon the SEI bacteria is typically kept in check or held at Bay by that normal flora but when they take certain antibiotics especially things like clomin or cyof loxin but even sometimes the penicillins or sephos sporin can cause this the normal flora enough of it can get killed or suppressed that that sea diff can start to overgrow grow out of control and cause an active infection and anybody who's had SE diff knows it's no joke moderate to severe cases we're talking multiple bouts of watery diarrhea abdominal pain bloating fever water and electrolyte imbalances and in severe cases they may need to be treated with a fecal transplant or even potentially surgery another example of this concept is the development of a yeast infection some females May notice that after taking a course of a broad spectrum antibiotic but they could develop a yeast infection as that rods spectrum antibiotic could suppress the normal vagin Flora allowing that candida or the yeast to overgrow causing that infection another unintended consequence of antibiotic use is an allergic reaction and I have plenty of patients that have an allergy to a certain antibiotic for example it's estimated that anywhere from 1 to 10% of patients can have some level of hypers sensitivity to the penicillins now luckily again most of those hypers sensitivities or those allergies are mild and mostly annoying like a maculopapular rash but some about 0. 5% can have the most serious hypers sensitivity reaction anaphylaxis fortunately death due to anaphylaxis from penicillin is quite uncommon and there are multiple antibiotics that we can choose from if somebody does have a hypers sensitivity to a certain antibiotic but still needs treatment for an infection so everything we've talked about so far definitely does not cover every potential side effect or reaction that can occur with antibiotic use that could take quite a bit of time if we continue down that road but I will include some additional side effects that are associated with some commonly used antibiotics in the description below the point is as beneficial as antibiotics can be they don't come without some Associated risks and that's one of the reasons why we don't want to just use them all willy-nilly we want to use them when appropriate like the classic misuse example taking an antibiotic for a viral respiratory infection that the body could just get over on its own now we're not just concerned about reducing the risk of unintended Side Effects by giving somebody an antibiotic when they don't need one we're also concerned about reducing the risk of antibiotic resistance bacteria are pesky little critters that have the ability to adapt and change in order to avoid being killed or suppressed by antibiotics for example there are some bacteria that have adapted to produce betalactamases which are enzymes that cleave the structural component of the antibiotic class the betal lactams essentially inactivating those antibiotics and if you remember the ayin and the sephos sporns belong to that betalactam class so those antibiotics would not work well against bacteria that can produce those betalactamase enzymes bacteria can also modify their ribosomes so that they're no longer a viable Target for certain antibiotics they can also change their cell membrane permeability and also can create little cellular pumps that can actively pump the antibiotic out of themselves you can kind of think of this as survival of the fittest in a way as we continue to use antibiotics the bacteria that are susceptible will be killed and die off but those bacteria that are resistant could continue to survive and they could share this genetic information that codes for resistance as they grow and divide and bacteria can even share genetic information with other bacteria in their surrounding environment on one hand that's super fascinating on another hand it's a little bit freaky decky but hopefully this gives you some good ideas of the importance of sound medical decision making and only using antibiotics when necessary versus just relying on that good oldfashioned immune system and of course it wouldn't be an Institute of human anatomy video if I didn't get a chance to say how excited I am about one of my favorite lifelong learning tools and that is brilliant brilliant.org is an amazing interactive online learning platform for stem subjects and I really believe it is one of the best and most fun engaging ways to learn math science and computer science I've been using brilliant for almost 2 years now and it has definitely helped me to refine and sharpen past skills as well as develop new ones I recently started one of their new lessons called exploring data visually which is all about analyzing and interpreting data from visualizing charts and graphs which has definitely been helpful for me plus brilliant is constantly adding more of these lessons each and every month so you'll definitely find lessons and courses that are applicable to you no matter where you are on your educational Journey so if you're interested in checking out this amazing learning platform go to brilliant.org to start a free 30-day trial plus the first 200 people will get 20% off their annual subscription we'll also include that information and the link in the description below thanks for watching our crazy Anatomy videos everyone like And subscribe if you feel the need and of course leave some comments below let us know what you thought of the video and we'll see you next time [Music]