Pathology scientific study of disease Pathogens bacteria that

• Pathology: scientific study of disease • Pathogens: bacteria that cause disease • Some bacteria cause disease by producing toxins (poisons) • Exotoxins: bacterial proteins; produced by Gram-positive Bacteria – Secreted into the surrounding environment – Tetanus is a disease caused by an Exotoxin. Ever cut yourself or step on a nail and had to take a shot? That was to prevent Tetanus 1

• Endotoxins: made of lipids & carbohydrates • associated with the outer membrane of Gram-negative bacteria, such as E. coli – Not released until bacteria dies – Cause fever, body aches, & weakness, & they damage the vessels of the Circulatory System 2

• Pathogenic bacteria are a major cause of human death and disease and cause infections such as tetanus, typhoid fever, diphtheria, syphilis, cholera, foodborne illness, leprosy and tuberculosis, pneumonia, Lyme disease, etc. – http: //biology. clc. uc. edu/courses/bio 106/bact-dis. htm • Bacterial diseases are also important in agriculture, with bacteria causing leaf spot, fire blight and wilts in plants, as well as Johne's disease, mastitis, salmonella and anthrax in farm animals. – http: //en. wikipedia. org/wiki/Bacterial_diseases 3

• Many antibiotics are derived from chemicals that bacteria or fungi produce; • 3 ways that antibiotics kill bacteria: – interferes with cell wall synthesis, ex: Penicillin – interferes with protein synthesis; ex: Tetracycline – inhibits RNA synthesis; ex: Rifampin • They affect only the growth of bacteria without harming the body cells of humans • Antibiotic Resistance – Overuse of antibiotics encourages drug-resistant strains to evolve through selection 4 – Mutant bacteria continue to grow