Lesson 17 18 3 Domain System Archaea o No peptidogylcan o Prokaryotic Bacteria o Contains peptidoglycan o Prokaryotic Eukarya o Contains carbohydrates o Eukaryotic Characteristics of Bacteria Peptidoglycan cell walls Ester linked lipids o Mostly phospholipids Ribosomes 70S unique to bacteria Genomes are single circular ds DNAs o Exceptions known Many have plasmids and transposons The Proteobacteria Largest of major groups Proteus mythical Greek god who could assume many shapes 5 subdivisions Photosynthetic and non photosynthetic forms Gram negative o Thin peptidoglycan layer o Outer membrane protection E Coli o LPS Most human pathogens The Alphaproteobacteria The alpha subdivision Important plant microbes o E g Rhizobium and Agrobacterium Home of the Rickettsia The Alphaproteobacteria know the general characteristics and what category they fall into Obligate intracellular parasites o Rickettsia Arthropod borne spotted fevers R prowazekii Epidemic typhus R typhi Endemic murine typhus 1 R rickettsii Rocky Mountain spotted fever o Rickettsia and mitochondria Mitochondria appear to be descendants of ancient rickettsial parasites The Betaproteobacteria The beta subdivision o Spirilla spirillum rhodocyclus o The Neisseria Bordetella o Gram negative Neisseria o N meningitides o N gonorrhoeae Spirillum o Helical Bordetella o Rods o B pertussis cause of pertussis or whooping cough Burkholderia Nosocomial infections The Gammaproteobacteria important The gamma subdivision best characterized The Enterics and relatives o E Coli The Vibrios and relatives The Pseudomonas o P Aeruginosa Legionella Coxiella Francisella The Epsilonproteobacteria Helicobacter pylori o Multiple flagella o Microaerophilic o Acidophilic o Peptic ulcers o Stomach cancer In 2005 Barry Marshall and Robin Warren were awarded the Nobel Prize in Physiology or Medicine for their discovery that peptic ulcer disease PUD was primarily caused by Helicobacter pylori Gram Positive Bacteria Cell wall is thick peptidoglycan Teichoic acids Endospore formers 2 The aerobic spore formers B anthracis anthrax B thuringiensis insecticide o The Streptococcus Taxonomically complex many pathogens Pneumococcus and pyogenes cause scarlet fever Pharyngitis sore throat o Bacillus and Clostridium Wall less forms o The Mycoplasma important The acid fast bacteria o Mycobacteria and relatives 2 major groups of Gram Positive Bacteria The low GC gram positive bacteria o Firmicutes The high GC gram positive bacteria o Actinobacteria Low GC Gram positive bacteria Firmicites The Bacillus class bacilli o Bacillus Aureus produce endotoxin common cause of food The wall less bacteria Mollicutes rheumatic fever o The Staphylococcus o Mycoplasma o Smallest genomes o Very small 0 1 0 25 um 5 of typical bacillus o Colony 1 mm Fried egg shape o Some can be cultured o M Pneumonia o Spiroplasma sp and Acholeplasma sp The high GC gram positive bacteria Actinobacteria Filamentous forms actinomyces Many soil bacteria Streptomyces o Smell of rich soil is due to Streptomycetes The acid fast bacteria o Lipophilic surface o Unusual lipids Mycolipids o The Mycobacterium Nocardia and Corynebacterium 3 Other Bacterial Groups Chlamydia Spirochaetes Chlamydia Obligate intracellular parasites 3 important species in group o Trachomatis Causes STD and conjunctivitis o Psittaci o Pneumoniae Causes psittacosis parrot fever Causes an atypical pneumonia Life cycle o Elementary body o Reticulate body Vegetative cell Non growing spore like o Given up much of metabolism Can t make ATP The Spirochaetes Spiral organisms with a sheath and axial filaments Slow growing aquatic free living or parasitic Several human pathogens o Treponema pallidum o Borrelia burgdorferi syphilis lyme disease Domain Archaea Extremophiles Hyperthermophiles o Pyrodictium o Sulfolobus Methanogens o Methanobacterium Extreme halophiles o Halobacterium Lesson 19 Dis ease lack of ease Key Terms Disease 4 o An abnormal state in which the body is not functioning normally Etiology o The study of the cause of a disease Infection o Growing and multiplying of pathogens in the host Infection Disease Koch s Postulates Detect agent in host s with the disease Re isolate the agent Isolate pure culture agent Induce disease in new host Exceptions to Koch s Postulates Some pathogens can cause several disease conditions or the same pathogen can cause different disease symptoms Some pathogens cause disease only in humans Some pathogens need cofactors o Not all develop disease Development of some diseases takes years Reservoirs of infection Continual sources of infection Human o AIDS gonorrhea o Carriers may have inapparent infections or latent diseases Animal o Rabies Lyme disease o Some zoonoses may be transmitted to humans Nonliving o Botulism tetanus o Soil water Transmission of disease Contact o Direct Requires close association between infected and susceptible host Touching kissing sexual intercourse Fomites Tissues towels bedding diapers drinking cups toys money Transmission via airborne droplets o Indirect o Droplet Vehicle 5 o Transmission by an inanimate reservoir o Food water Vectors o Arthropods especially fleas ticks and mosquitoes o Mechanical Arthropod carries pathogen on feet Flies transfer pathogens typhoid fever from feces of infected to food o Biological Pathogen reproduces in vector Lymes WNV History of epidemiology John Snow o Mapped the occurrence of cholera in London Ignaz Semmelweis o Showed that hand washing decreased the incidence of puerperal fever Florence Nightingale important o Prominent English nurse writer and statistician o Showed that improved sanitation decreased the incidence of epidemic typhus Prevention and control Barriers isolation and quarantine Public health o Cleanliness safe food and water Immunization herd immunity Eradication of disease o Smallpox polio rabies Center for Disease Control and Prevention Collects and analyzes epidemiological information in the United States Publishes Morbidity and Mortality Weekly Report MMWR www cdc gov Morbidity o Incidence of a specific notifiable disease o Deaths from notifiable diseases o Number of people affected in relation to the total population in a given time o Number of deaths from a disease in relation to the population in a given time Mortality Morbidity rate period Mortality rate Lesson 20 Nosocomial hospital acquired infections Any infection that is acquired during the course of stay in a hospital nursing home or other health care facility 6
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