This lesson will give you a basic understanding of what human flora is. You’ll learn about the different locations of flora, such as the gut, and what mutualistic, commensal, and opportunistic microbes are.
Your Microbial Friends
Some little kids have invisible friends when growing up. These friends provide them comfort, support, and so on. Regardless of whether or not you had these friends when growing up, you have them right now. I’m being serious, too.
You have invisible friends that are silently helping you live a better life. And no, I’m not crazy. Without them, you’d be in a world of trouble.These friends are alive. They are on you and they are in you. That sounds a bit scary, but it’s true. Of course, ‘invisibility’ is a relative term.
It’s not like these friends are ghosts. They’re actually tiny microbes, such as bacteria, that cannot be seen with the naked eye. This lesson will go into how these friends help protect you and where they are located.
Human and Mutualistic Flora
The microbes that reside on or within a human, some of which are beneficial to a person’s survival, are known as human flora. Some of the microbes in human flora are mutualistic microorganisms, meaning they are organisms that derive a benefit from and provide a benefit to their host. Essentially, mutualistic bacteria are like your invisible best friend. You make them laugh and they make you laugh.
They cook for you and you cook for them.
In real life, one prime example of mutualistic flora is found in a collection of microbes living in your digestive tract, collectively referred to as gut flora. Here, mutualistic gut flora is provided with nutrients by way of the food you eat. Yeah, they basically siphon off a little bit of that food for themselves before your own body even gets a piece.
They do this so they can survive and live off of something. They have to eat, too!However, they provide you with more than one thing in return that is of benefit for you. For example, they help you digest your food and help to kill off flora that may be bad for you, meaning they essentially prevent certain diseases from occurring by killing off the bacteria in your gut that may cause such diseases.
The bad or potentially bad microbes found in human flora, gut or otherwise, are known as opportunistic pathogens. These are microbes, such as fungi and bacteria, that take advantage of a host’s weakened immune system.In the case of our mutualistic gut flora, they actually help to keep down the levels of some of the opportunistic pathogens through competition, meaning your best friends in your gut either directly kill these bad bacteria or fungi or they outcompete them for resources, such as food, causing the opportunistic bacteria to die in the process due to starvation.In essence, you can liken this little, but important, process to your best friend withholding food from your enemy and giving it to you instead or your best friend going and just punching the lights out of your enemy in order to keep you safe and healthy.
Besides having friends and enemies inhabiting your body, you may also have commensal microbes in your flora as well. Commensal microbes are microbes that live in a non-harmful co-existence with their host. This basically means they don’t benefit you like your friend or try to hurt you when you’re down like your enemy; they are just there.
Working off of our example from before, if your enemy is trying to hurt you and your friend is trying to help you in a fight, then the commensal organisms are the bystanders that just stand there for the sheer enjoyment of watching a fight. They do nothing otherwise. They don’t help you or hurt you.In reality, commensal organisms may actually derive a benefit from you, such as a having place to live, but in the end, whatever benefit they derive from you doesn’t affect you negatively, and therefore they are not considered to be pathogenic, or disease-causing, microorganisms in a healthy person.
Other Types of Flora
Regardless of whether a microbe is opportunistic, mutualistic, or commensal, they don’t just have to live in the gut.
Microorganisms that live on the skin are unsurprisingly known as skin flora, microbes that live in the vagina are known as vaginal flora, and so on. There’s flora almost everywhere on your body that you can lay your eyes on and, in some cases, such as your gut, in places where you can’t even see inside of.And that’s usually a good thing, unless you get sick due to another disease or due to your doctor’s prescription.
I’m going to get in so much trouble for saying that. But the reality is antibiotics that are designed to help you may in some cases actually hurt you as well.The problem is that some antibiotics that are given for your protection actually kill off mutualistic microbes in the process. The infection that you were given antibiotics for combined with the potentially deleterious effects of that antibiotic may predispose you to opportunistic infections in some cases.For example, an opportunistic vaginal infection caused by the fungus Candida albicans may occur if a woman is given a course of antibiotics that kills off her mutualistic vaginal flora. If the mutualistic flora is killed off, the fungus will be able to grow unchecked, causing an infection and disease that otherwise would not have occurred if she were perfectly healthy.
That doesn’t mean you should ever refuse proper antibiotic treatment. Just be aware that unless research hasn’t found it yet, there’s no such thing as something without a side effect if it causes an effect to begin with.
So, in this lesson we covered something known as human flora. These are the microbes that reside on or within a human, some of which are beneficial to a person’s survival.Human flora is found everywhere, which is why it’s subdivided by the location of where these microbes reside.
For example, microorganisms that live on the skin are unsurprisingly known as skin flora. Microbes that live in the vagina are known as vaginal flora, and a collection of microbes living in your digestive tract are collectively referred to as gut flora.Some of the microbes in human flora are mutualistic microorganisms, meaning they are organisms that derive a benefit from and provide a benefit to their host.The bad, or potentially bad, microbes found in human flora, gut or otherwise, are known as opportunistic pathogens. These are microbes, such as fungi and bacteria, that take advantage of a host’s weakened immune system.
Besides opportunistic or mutualistic microorganisms, you may also have commensal microbes in your flora as well. Commensal microbes are microbes that live in a non-harmful co-existence with their host.
After this lesson, you should be able to:
- Define human flora
- Recall some of the places where flora is found in the human body
- Describe the differences between mutualistic microorganisms, commensal microbes, and opportunistic pathogens, and examine each of their relationships with humans
- Explain how antibiotics can have negative effects