requiring hospitalization, while the American College of Chest Physicians does not. One reason for such a discrepancy is that normal, healthy lungs have bacteria, and sputum cultures collect both normal bacteria and those which are pathogenic. However, pure cultures of common respiratory pathogens in the absence of upper respiratory flora combined with symptoms of respiratory distress provides strong evdience of the infectious agent, and its significance. Such
234 Illustrated Dictionary of Microbiology pathogens include Streptococcus pneumoniae, Haemophilus injluenzae and the highly infectious Mycobacterium tuberculosis which are transmitted by inhailing aerosols. For this reason, laboratory processing of sputum for respiratory pathogens are performed with the aid of a biological safety cabinet. Staining : Is an auxiliary technique used in microscopy to enhance contrast in the microscopic image. In biochemistry it involves adding a class-specific (DNA, proteins, lipids, carbohydrates) dye to a substrate to qualify or quantify the presence of a specific compound. It is similar to fluorescent tagging. Stains and dyes are frequently used in biology and medicine to highlight structures in biological tissues for viewing, often with the aid of different microscopes. Stains may be used to define and examine bulk tissues (highlighting, for example, muscle fibers or connective tissue), cell populations (classifying different blood cells, for instance), or organelles within individual cells. Biological staining is also used to mark cells in flow cytometry, and to flag proteins or nucleic acids in gel electrophoresis. Staining is not limited to biological materials, it can also be used to study the morphology of other materials for example the lamellar structures of semicrystalline polymers or the domain structures of block copolymers. Staphylococcus aureus : Is the most common cause of staph infections. It is a spherical bacterium, frequently found in the nose and skin of a person. About 20% of the population are long-term carriers of S. aureus. S. aureus can cause a range of illnesses from minor skin infections, such as pimples, impetigo (may also be caused by Streptococcus pyogenes), boils, cellulitis folliculitis, furuncles, carbuncles, scalded skin syndrome and abscesses, to life-threatening diseases such as pneumonia, meningitis, osteomyelitis, endocarditis, Toxic shock syndrome (TSS), and septicemia. Its incidence is from skin, soft tissue, respiratory, bone, joint, endovascular to wound infections. It is still one of the four most common causes of nosocomial infections, often causing postsurgical wound infections. Abbreviated to S. aureus or Staph aureus in medical literature, S. aureus should not be confused with the similarly named (and also medically relevant) species of the genus Streptococcus.
You've reached the end of your free preview.
Want to read all 299 pages?