15.1-8 Bacterial Diseases Microbiology

Background BC Roman Marcus Terentius Varro proposed minute creatures cause disease. Middle Ages Miasma Theory ”bad air” caused disease. 1546 Germ Theory proposed by Girolamo Fracastoro but no proof. 1656 Athanasius Kircher first to observe microorganisms. 1808-1813 Agostino Bassi proved microorganisms caused disease. 1847 Ignaz Semmelweis proved proper sanitation reduced infection. 1854 John Snow determined cholera caused by exposure to sewage. 1860-1864 Louis Pasteur scientific proof of Germ Theory of Disease.

Background 1884 Robert Koch’s Postulates: The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms. The microorganism must be isolated from a diseased organism and grown in pure culture. The cultured microorganism should cause disease when introduced into a healthy organism. The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent. 1870s Joseph Lister developed aseptic surgical techniques.

15.1 Diagnosing Microbial Diseases Microbial Culture-streak plate Microscopy-pathology Molecular Diagnostics-PCR

15.2 Microbial Diseases of the Skin Skin Flora (microbiota) have commensalistic and mutualistic relationship. Proper hygiene essential to good health.

15.2 Bacterial Skin Diseases Impetigo-Highly contagious, commonly found in pre- school children caused by Staph. aureus & Strep. pyogenes.

15.2 Bacterial Skin Diseases Erysipelas-acute streptococcus infection of the upper dermis.

15.2 Bacterial Diseases of the Skin Cellulitis is inflammation of connective tissue within the layers of the skin.

15.3 Bacterial Diseases of the Eye Conjunctivitis (pink eye) is infection of the outermost part of the eye and the innermost layer of the eyelids.

15.3 Bacterial Diseases of the Eye Keratitis is inflammation of the cornea.

15.4 Bacterial Diseases of the Nervous System Meningitis is inflammation of the protective membranes of the brain and spinal cord. Symptoms: severe headaches and neck stiffness. Can lead to paralysis, brain damage and death. A lumbar puncture is used for diagnosis.

15.4 Bacterial Diseases of the Nervous System Botulism is caused by toxins produced by the anaerobic Clostridium botulinum. Type of food poisoning. Causes paralysis and death. Botox treatment

15.4 Bacterial Diseases of the Nervous System Leprosy (Hansen’s Disease) Carried by armadillos

15.4 Bacterial Diseases of the Nervous System Tetanus (lockjaw)- prolonged muscle contraction

15.5 Bacterial Diseases of the Nervous System Lyme Disease Tick-bourne Bullseye pattern

15.5 Bacterial Diseases of the Nervous System Plague 33% death rate in Europe between 1347-1353. Fleas are infected and carried by rodents.

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Endocarditis-Inflammation of the inner tissues of the heart. Myocarditis-inflammation of the heart muscle.

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Sepsis & septic shock 25-50% mortality rate.

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Rheumatic Fever-untreated strep throat. Arthritis Heart damage

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Tularemia (rabbit fever) Carried by ticks, flies & mosquitos. Extremely contagious

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Brucellosis Carried by domestic livestock & pets. Fever, joint pain & fatigue.

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Anthrax spores can be inhaled and are deadly for 100s of years. Fatality rates of 80% or higher.

15.8 Bacterial Diseases of the Cardiovascular & Lymphatic Systems Gangrene-death of tissue (necrosis). Usually results in amputation or death.