Streptococci :: essays research papers

StreptococciIn a healthy human, the indwelling tissues much(prenominal) as blood, brain, and muscle ar generally free of microorganisms. On the other hand, the surface tissues, such as skin, all of the mucous membrane in the mouth, nasal cavity and intestinal tract can comfortably and readily capture available for microorganism to colonize and grow. Depending on the posture in the human body, different bacterium choose to grow on a specific location that provides the nutrition it needs, with optimum condition such as pH. thither are many different bacterium that jointly are called normal flora, and live in the human body. Many of these bacterium are commensally living in humans, and some others are symbiotic. commensal bacteria altogether obtain their food from the human, and do not vituperate or benefit the host, on the other hand symbiots not only get their food from the host, but in return they also become beneficial to the host in providing nutrition that human can not make, such as vitamin K. One of the most recognized and extensively study bacteria that often get more attention during the winter is Streptococcus. There are different strains of streptococci. Depending on their ability of hemolysis of blood nutrient agar, strep can be subdivided into a, b and g hemolytic (1-pp143). There are many different laboratory tests that can be done to see one strep from the other. Different treatments also have been developed to get by for each one strain of strep.The streptococci are a group of bacteria that infect human as well as animals. A very(prenominal) basic test to recognize strep is to perform blood agar plate (BAP) test. Hemolysis of the blood agar can indicate the presence of strep bacteria. Most strep bacteria are either a or b hemolytic on sheep blood agar. a-hemolytic strep part lyses the red blood cells, creating a greenish district around each colony, whereas, complete lyses of blood by b-hemolytic strep create a wanton zone. g-hemolytic does not lyse red blood cells, and no change or zone is created (1-pp143). Streptococci are gram positive and exhibit purple seeming cocci when gram stained and observed under the microscope. Gram-positive bacteria such as streptococci have a membrane that contains a thick layer of peptidoglycan. Peptidoglycan can retain the violet blue, and does not flop off with alcohol. It grows in short chains, containing several streptococci. It looks a lot wish a string of beads.