Exam 3 Microbiology PDF

Exam 3 Microbio Prokaryotes - Remember that prokaryotes are divided into 2 domain: bacteria and archaea - Prokaryotes→ peptidoglycan and pseudomurein… peptidoglycan →domain bacteria→ Gram + (Low G+C ; High C+G) and Gram - (proteobacteria and nonproteobacteria) Proteobacteria...

Exam 3 Microbio Prokaryotes - Remember that prokaryotes are divided into 2 domain: bacteria and archaea - Prokaryotes→ peptidoglycan and pseudomurein… peptidoglycan →domain bacteria→ Gram + (Low G+C ; High C+G) and Gram - (proteobacteria and nonproteobacteria) Proteobacteria - LArgest group of bacteria with more than 500 genera and 2000 species - All are gram negative; some are motile - Most are facultative anaerobes - Named after greek god proteus - Divided in to classes: alpha, beta, gamma, delta, and epsilon Class 1: Alphaproteobacteria - Known for living in low nutrient environment - Unusual morphology including buds or stalks - STalks that are used to adhere to a surface are called prosthecae - Caulobacter: stalked bacteria found in lakes - Pelagibacter ubique: 25% of all prokaryotes in the ocean are these species - Assist with carbon cycles and serves as carbon sinks - Alphas are important to the environment - Rhizobium are good for plants and crops, allow nitrogen fixation at the roots, and also helps plant grow faster and stronger - Agrobacterium: inserts a DNA plasmid into a plants cells which induces tumor formation (which are harmful pathogens that causes Crown Gal Disease - This also can cause diseases in humans - Obligate intracellular parasites meaning they cannot make ATP - The genus Rickettsia can reproduce within mammalian cells - Generally transmitte through insect bites such as lice, ticks, mites and rat fleas - Typhus and Rocky Mountain spotted fever - ^ Typhus was common during wars and famines and caused a rash, fever, headache and delirium - This is not typhoid fever (different bcaterium/different disease) - Historically has a high mortality rate - RMSF typically causes a rash, fever, confusion, and muscle aches - Treated with doxycycline - Rash is called petechia; rash and is painless (wrist, soles, ankles, palm, forearms) Ticks: Vector of Disease - Ticks are often vectors to diseases - Recent research has shown that tick bites can have unexpected and long term health effects if resulting in infections - Lyme Disease (black legged brown tick) - Lone star tick is suspected to spread these illness as well as an alph gal allergy that causes an allergy to red meat Alphaproteobacteria - Chlamydia trachomatis: pain with urination, sex, and bleeding after sex - If left untreated it can lead to sterility Class 2: Betaproteobacteria - Beta class needs a lot of organic nutrients to survive - It has several organisms in this group that are major pathogens for humans since they use us as nutrient source - It tends to leave their host feeling exhausted, run down, ans can live in their hosts for long periods of time id not treated - The human pathogen have been arounds since greek times which are (Neisseria gonorrhoeae and N. meningitidis - Unfortunately we now also have MDR strains due to over and misuse of antibiotics - Fastidous, G- cocci that live in mucosal membrane of mammals - Usually grown on chocolate agar (not exactly chocolate) - Grow as diplococci, resemble two coffee beans - Neonatal conjunctivitis - Bordetella pertussis: G-, non motile, aerobic bacillus - Whooping cough: Produces toxins that paralyzes movement of cilia in respiratory tract causing severe cough and mucous build up - Results in slow suffocation of infant or toddler - Mortality rate of 19-37% depending on access to medical care - Ciliated cells of respiratory system infected with Bordetella pertussis Class 3: Gammaproteobacteria - Largest subgroup of proteobacteria ans the most diverse group - Many of the microbes in this group are human and plant pathogens as well as normal gut form flora - Genera are separated by metabolic pathways,m growth requirements, appearance, and motility - Pseudomonadales: include pseudomonas, moraxella, and acinetobacter (acinetobacter is potential flesh eater) - These organism are motile, G- rods with polar flagella - Most are considered to be opportunistic pathogens - Many species have evolved to grow inside antiseptic - Often produce water soluble pigments - Moraxella: causative agents of chronic conjunctivitis (pink eye) - Pseudomonas: often associated with burn patient infections and with lung infections - Can cause UTIs, ear infections, and build biofilms making the hard to treat - Generally found in the environment and with water source - Often produce water soluble pigments - Legionellales: found in streams, warm water pipes, cooling towers - L. pneumophilia causes Legionnaires disease - Vibrionales = Vibrio: found in coastal and fresh water - Vibrio parahaemolyticus causes gastroenteritis - Vibrio cholerae causes cholera (facultative anaerobes)  - Vibrio cholerae rice water stool - Pasteurellales: can cause pneumonia and septicemia - Transmitted by inhalation of droplets, ingestion of contaminated food and water, animal bites, scratches, or licks - If from an animal bite will see signs of cellulitis within 24 hours - Enterobacteriales (enterobacteriaceae enterics) - Inhabit the intestinal tracts of human and other animals, have peritrichous flagella and are facultative anaerobes - Salmonella enterica: hundreds of serotypes, often named by place of origin - Salmonellosis is usually associated with food and eggs - Salmonella typhi: Typhoid Mary and typhoid fever → died of north brother island, infected 50-100 people and killed 10 More enterics - Escherichia and Enterobacter: opportunistic pathogens that are commonly associated with UTIs - Serratia marcescens: often associated with nosocomial infections - Shigella: bacillary dysentery or shigellosis - Proteus: swarming colonies that can cause UTIs - Yersinia pestis: plague(black plague), vectored by fleas, large capsules Class: Deltaproteobacteria - This class includes bacteria that prey on other bacteria - Bdellovibrio species get their energy by lysing or bursting open other bacteria - They also prey on other gram negative bacteria - SOme are important strains: Desulfovibrinales: sulfur reducing bacteria that use S instead of O2 as their final electron acceptor Class 5: Epsilonproteobacteria - Slender gram negative rods that are either helical or vibrio - Tend to be: Microaerophiles - Include Helicobacter pylori: Causes peptic ulcers and have been linked with stomach cancer - Barry Marshall in Australia proved correlation - Campylobacter jejuni: can caused intestinal infection and could trigger Guillain Barre Syndrome The Non-proteobacteria - Gram negatives that are not in the proteobacteria group - Most species in this group are able to perform photosynthesis to produce their own energy - Also includes gram negative spirochaetes: STI transmission, causes lesion and rash - If pregnant with untreated syphilis can have 40% chance of stillbirth, or may cause deafness or deformities Gram Positive Bacteria - Can be divided into two phyla groups based on DNA - Low G+C ratio have less than 50% guanine and cytosine in their DNA (DNA is primarily made with A-T combinations)  - Phylum Firmicutes: INclude Clostridiales, Bacillales (Bacillus, Listeria, and Staphylococcus), Lactobacillales (streptococcus), Mycoplasmatales (don't make cell walls). Low G-C (high A-T combo) Gram positives - Clostridium: Endospore producing and obligate anaerobes - Clostridium perfringens: Gram positive and spore forming rod - Produces gas gangrene - Risk include trauma, surgery, diabetes HIgh G+C (low A-T combo) Gram positives - Actinobacteria - Actinomyces - Corynebacterium - Gardnerella - Mycobacterium - Propionibacterium - Streptomyces - Many strains are pleomorphic and grow in filaments or cord arrangements High G-C (low A-T combo) Gram positive - Propionibacterium commonly associated with acne infections (P. acnes; Aerotolerant anaerobe) - Corynebacterium (C. diphtheria; causes diphtheria: Thick covering in the back of the throat.. Can result in difficulty breathing, heart failure, paralysis, and death - DPT vaccine is for Diphtheria, pertussis, and tetanus - The acid fast trains.. - Nocardia- tends to cause deep pustules in the skin - Spread by bacteria in soil and water, but not person to person - Can moved to the bloodstream and attack the brain - Mycobacterium: spread through aerosols (“coughing, singing, talking, laughing, sneezing) - Also called the “White Plague” and “consumption” (consumes the patient causing weight loss and wasting) - Treatment can last over 6 months for acid fast strains Next Domain: Archaea - Have pseudomurein cell walls (only have NAG not NAM sugars) - Multiple morphologies (size, shape, arrangements) - Tend to live in extreme environments - Hyperthermophiles in boiling hot geysers - Methanogens making methane deep in the soil - Halophiles living in salty waters - Causes pink salt lakes in Utah ans in Owens valley in California The Archaea - None are pathogenic - Deinococcus radiodurans: more resistance to radiation than endospore - Thermus aquaticus: hot spring in yellowstone National PArk  - Source of tag polymerase used in PCR to copy DNA segments Microbial Diversity - PCR indicates that there can be up to 1 billion bacteria in a single gram of fertile soil - Many bacteria have not been identified yet because they haven't been cultured - Require special nutrients and conditions - Need to be cultured to understand their metabolism and ecological role