Streptococci :: essays research papers

StreptococciIn a healthy human, the internal tissues much(prenominal) as blood, brain, and muscle atomic number 18 generally free of microorganisms. On the other hand, the surface tissues, much(prenominal) as skin, all of the mucous membrane in the mouth, pinched cavity and intestinal tract can easily and readily become available for microorganism to colonize and grow. Depending on the location in the human body, disparate bacteria choose to grow on a specific location that provides the nutrition it needs, with optimum condition such as pH. There be many a nonher(prenominal) incompatible bacteria that collectively are called normal flora, and live in the human body. Many of these bacteria are commensally living in humans, and whatsoever others are symbiotic. Commensal bacteria only obtain their food from the human, and do not harm 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 p roviding nutrition that human can not make, such as vitamin K. One of the most recognized and extensively studied bacteria that often get more attention during the winter is Streptococcus. There are different strains of strep. Depending on their ability of hemolysis of blood agar, strep can be subdivided into a, b and g hemolytic (1-pp143). There are many different laboratory tests that can be done to distinguish one strep from the other. Different treatments also have been developed to fight each strain of strep.The streptococcus are a group of bacteria that infect human as well as animals. A very 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 partially lyses the red blood cells, creating a greenish govern just about each colony, whereas, complete lyses of blood by b-hemolytic strep create a clea r 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 color 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 wash off with alcohol. It grows in short chains, containing several streptococci. It looks a lot like a string of beads.