Friday, March 4, 2011
Eww. Bacteria.
Have you ever wondered just how well certain cleaning agents work? How much bacteria do they really kill? My biology class recently did a lab to test the efficiency of common antibacterial products.
You may know that bacteria are some of the simplest and most numerous life forms on Earth. In fact, there are approximately ten times as many bacteria cells in the human flora than there are human cells in the body. Not all bacteria is bad though. In fact, bacteria is vital to all life forms! They even help in the production of foods like cheese and yogurt. We all know that there are also harmful bacteria out there just waiting to infect our bodies!! We use antibacterial and antimicrobial soaps to kill off these pesky little single cellular organisms when we wash our hands.
Disinfectants can only be used on non-living objects. Some examples of disinfectants include bleach, rubbing alcohol, and Germ-X. If and living organism digested a disinfectant they would either have to rush to a posion control specialist, or die. Antiseptics are antimicrobial substances that can be applied to living tissue/skin. Examples of antiseptics include mouthwash and soap. Isopropyl alcohol can be used as both a disinfectant and antiseptic.
Common household cleaning agents, such as disinfectants and antiseptics, do the same---they kill bacteria. You can think of it as World War III: Humans vs. Microorganisms. Our society has become anti-bacteria CRAZED. In fact, our obsession with being super clean causes some scientists to sit on the edge of their seats. They are worried that our bacterial resistance will lead to the development of resistant strains that our disinfectants and antiseptics can no longer fight off.
During our lab, we did two trials. The first one we swabbed our skin and the second trial we got to swab any non living surface to see how much bacteria was growing there. During the skin trial we swabbed our "dirty hands" (we weren't allowed to wash our hands for several hours prior to our lab) with a sterile cotton swab that was dipped in distilled water, then a new swab dipped in isopropyl alcohol, and finally we washed our hands with antibacterial soap and swabbed our hand with a new cotton swab before we tried our hands off. After each swabbing we zig zagged the cotton swab in one of the 6 sections of our petri plate of agar that looked like this.
After our skin trial, we moved on to our surface trial. I decided to pick the knob of one of the sinks in the girls lockerroom since it probably got quite a bit of action and probably not very high on the priority level of the janitorial staff. The three treatments (cotton swabs) that we used for this trial were distilled water, alcohol, and bleach. The bleach treatment worked the best in the surface trial, for after the petri dish incubated, there was no bacterial growth in the bleach section of the agar.
You may know that bacteria are some of the simplest and most numerous life forms on Earth. In fact, there are approximately ten times as many bacteria cells in the human flora than there are human cells in the body. Not all bacteria is bad though. In fact, bacteria is vital to all life forms! They even help in the production of foods like cheese and yogurt. We all know that there are also harmful bacteria out there just waiting to infect our bodies!! We use antibacterial and antimicrobial soaps to kill off these pesky little single cellular organisms when we wash our hands.
Disinfectants can only be used on non-living objects. Some examples of disinfectants include bleach, rubbing alcohol, and Germ-X. If and living organism digested a disinfectant they would either have to rush to a posion control specialist, or die. Antiseptics are antimicrobial substances that can be applied to living tissue/skin. Examples of antiseptics include mouthwash and soap. Isopropyl alcohol can be used as both a disinfectant and antiseptic.
Common household cleaning agents, such as disinfectants and antiseptics, do the same---they kill bacteria. You can think of it as World War III: Humans vs. Microorganisms. Our society has become anti-bacteria CRAZED. In fact, our obsession with being super clean causes some scientists to sit on the edge of their seats. They are worried that our bacterial resistance will lead to the development of resistant strains that our disinfectants and antiseptics can no longer fight off.
During our lab, we did two trials. The first one we swabbed our skin and the second trial we got to swab any non living surface to see how much bacteria was growing there. During the skin trial we swabbed our "dirty hands" (we weren't allowed to wash our hands for several hours prior to our lab) with a sterile cotton swab that was dipped in distilled water, then a new swab dipped in isopropyl alcohol, and finally we washed our hands with antibacterial soap and swabbed our hand with a new cotton swab before we tried our hands off. After each swabbing we zig zagged the cotton swab in one of the 6 sections of our petri plate of agar that looked like this.
After our skin trial, we moved on to our surface trial. I decided to pick the knob of one of the sinks in the girls lockerroom since it probably got quite a bit of action and probably not very high on the priority level of the janitorial staff. The three treatments (cotton swabs) that we used for this trial were distilled water, alcohol, and bleach. The bleach treatment worked the best in the surface trial, for after the petri dish incubated, there was no bacterial growth in the bleach section of the agar.
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