Biosafety Levels of Various Microbes
Microbes are everywhere, and they serve many purposes. Some can be used in food production, others in agriculture, even in bioremediation (where microbes clean the environment by eating pollution such as oil spills). Some microbes are far more dangerous than others, but scientists still study how they affect plants or animals; this knowledge may help them develop a medical treatment or vaccine. Therefore, agencies such as the Centers for Disease Control and Prevention (CDC) provide a method of classifying microbes based on their risk level. The classifications are known as biosafety levels (BSL). These classifications can guide professionals to set up their work environment, choose what gear and protective equipment to use, and safely work with the microbe. These precautions are necessary to maintain safety of the professionals and surrounding community. Biosafety level 1 organisms are the safest to work with, and they get progressively more dangerous up to biosafety level 4. Each rank builds on additional precautions to the previous rank.
BSL-1 organisms are pretty tame, and do not usually cause illness in healthy adults. The lab facility will need a sink for scientists to wash their hands, and a closed door to separate the room from the rest of the building. Scientists will cover up so they don't get the bacteria on them (can't be too careful!), wearing a buttoned up lab coat, goggles, and gloves. They can work with these organisms on an open lab bench; they won't need extra equipment to contain them. Some species of BSL-1 bacteria are Lactobacillus acidophilus (found in our intestines and other body parts, can be added to yogurt and fermented foods) and Pseudomonas fluorescens (can be used in agriculture to suppress plant disease).
BSL-2 organisms are moderately risky as they can cause certain illnesses, more or less serious. Remember the precautions we listed for BSL-1? Let's make them a bit more serious to match! The doors will close by themselves, and entry will be limited- only authorized people may come in. Add on an eye washing station. They may consider wearing a face shield if needed. They may work with a biosafety cabinet to contain any dangerous splashes or sprays of bacteria. They'll need a stronger method of cleaning up equipment, like an autoclave (a machine that sterilizes things with hot steam) Some species of BSL-2 bacteria are Streptococcus pneumoniae (causes community-acquired pneumonia, a serious lung infection) and Bordetella pertussis (causes whooping cough, a respiratory infection).
BSL- 3 organisms cause serious, even potentially lethal diseases. A person may catch these diseases just by breathing in the microbes. Therefore, professionals have to be EXTREMELY serious about directing airflow and limiting the path of the microbes. Scientists will enter through two sets of self-closing doors. Lab entry is tightly monitored at all times, so only authorized people may enter. Air flow is designed to bring clean air INTO the lab, and not to let any air into surrounding areas, because the lab air might be contaminated. Anyone working with BSL-3 will be monitored for medical complications, and will take vaccines if needed against the pathogens. Add on a respirator (fitted mask to filter out contaminants so they only breathe cleaner air) if needed. They will always keep the microbes in a biosafety cabinet as they work, just to keep them from floating around in the air. Examples of BSL-3 bacteria species are Yersinia pestis (causes plague) and Chlamydia psittaci (causes psittacosis, a disease that affects mainly birds as well as mammals. Some symptoms in birds are low appetite, trouble breathing, and diarrhea. Humans may experience fever, aches, and a dry cough.).
BSL-4 organisms are the most dangerous. They are not worked with often; currently, 59 labs around the entire world work with BSL-4s. Not only do these organisms cause horrible diseases, those diseases don't have a known vaccine or treatment. Therefore, scientists take majorly strict precautions when working with these microbes. Before they enter, they change their clothes; they clean their equipment and take a shower to clean themselves before leaving the lab. Scientists will have to keep the microbes in a class 3 Biosafety cabinet as they work with them, or wear a positive pressure suit, which is a sealed full body with its own air flow (in a way, similar to an astronaut suit). The lab facility would be designed to be separate and self-contained to limit airflow between any other rooms; this decreases the risk of microbes flying into another room! The room will have its own air flow, vacuum and decontamination systems. A very widely known example of a BSL-4 organism is Ebola virus (mostly fatal, affects people and primates, causes symptoms such as fever, aches, vomiting and bleeding).
My article was meant to give a general idea of BSLs, and there are additional details that go in to maintaining a safe work environment. If you'd like to learn more about BSLs, you can look them up on the CDC's website. Here's one link to help you get started, where I got most of the information for this article: https://www.cdc.gov/training/quicklearns/biosafety/
