How can we identify the cause of an infection? - OCR 21st CenturyBacterial growth in cultures
There are many kinds of pathogens that cause infections. Scientists use a variety of tests to learn more about the pathogen causing an individual's disease in order to identify it.
In order to identify the pathogen it may be necessary to grow the bacteria in a cell cultureGrowing cells in the laboratory. The conditions are carefully controlled. The cells are grown in or on a growth medium. They are often kept warm in an incubator., under carefully controlled conditions. In the right conditions bacteriaSingle-celled microorganisms, some of which are pathogenic in humans, animals and plants. Singular is bacterium. can replicate approximately every 20 minutes. If it is colder or there are not enough nutrients they will multiply more slowly.
growth mediumA liquid or jelly, eg agar used in cell culture. It contains nutrients to enable the growth of cells. is a liquid or gel which provides all the nutrients needed for bacteria to grow successfully. These must include: carbohydrates for energy, nitrogen for protein synthesisThe production of proteins from amino acids, which happens in the ribosomes of the cell., and other minerals.
agar plateA Petri dish that contains agar gel and usually some nutrients. Agar plates are used to culture (grow) bacteria and fungi in the lab. are created by pouring hot molten agar-based growth medium into sterile Petri dishA clear glass or plastic dish, used to grow living cells from organisms so they can be studied., where the agar is allowed to set. Bacteria can be spread onto the plates using a wire loop. After a day or two they will have grown into individual coloniesA visible cluster of microorganisms. of the specific bacterium.
The culture conditions can be changed to suit the pathogen which is being grown. Their preferred growing conditions can help us identify them.