Microbiology 101 Week 12 Lecture Notes
Microbiology 101 Week 12 Lecture Notes 101.0
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This 7 page Class Notes was uploaded by Isabel Markowski on Sunday December 13, 2015. The Class Notes belongs to 101.0 at University of Wisconsin - Madison taught by a professor in Fall 2015. Since its upload, it has received 28 views. For similar materials see General Microbiology in Microbiology at University of Wisconsin - Madison.
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Date Created: 12/13/15
Microbiology 101 Week 12 Lecture Notes Microbes of the Respiratory Tract 0 Upper Respiratory Tract URT larynx oral cavity pharynx nasopharynx sinuses 0 Lower Respiratory Tract LRT lungs trachea bronchi 0 Larger surface area 0 Lungs alveoli specializedforgas exchange 0 Antimicrobialfeatures o immune cells in tissues 0 mucociliary clearance escalator mucus and saliva swalowed Microbiota of Resp Tract o URTheaviycoonized o Nasal microbiota diversedistinct from oral and skin biota 0 Main location of staph Aureus strept Pneumonia and othercommensal pathogens 0 LRT 0 Few microbes Pathogens of Resp Tract o URT 0 Mostly bacteria and viruses May damage URT defenses tend not be lifethreatening directly 0 Rhinitis sinus infection strep diphtheria o LRT 0 Many bacterial viral and fungal causes 0 More likely to be serious 0 Ex influenza Avirus Streptococcus Pneumoniae o Bronchitis pneumoniawhoopingcough 0 Transmission 0 HumanAnimal reservoir I Person gtperson direct via aerosols airborne particles and secretions I Within one person 0 Aspiration from URT to LRT 0 Spread tofrom other part of body 0 Environmentalreservoiregfungus I Inhalation from environment generally not transmissible to others InfluenzaAVirus 0 Basic Biology 0 Enveloped virus 0 Single stranded segmented different chromosome pieces negative strand 0 RNA Genomecompex RNA 2 strands O Positive Plus Translation is mRNAform 5 AUG 3 gt Protein gt Negative Minus H 5 CAU 3 Negative strand complementary of plus strand I Unique Don t directly transcribe to protein first copied to 1st strand sense DNA Dependent RNA Polymerase gt DNA gt RNA gt Protein DNA dependent DNA polymerase DNA I RNA dependent RNA polym aka replicase SURE Enzymezcan convert RNAto RNA and vice versa These are often quote rrorprone with high mutation rate 0 0 Main antigens I Neuraminidase NA cuts sialicacid residues I Hemagglutinin HA siaicacidbinding receptor sialic acid in sugars on susceptiblecell Replication a Endocytosis into susceptible cell binding of HA b Endosome c Fusion release ofviral capsid d Capsid gtnucleus and vRNA released copied to gt proteins i Also can now make negative RNA enzyme acts 2x e Proteins and RNA gt cytosol f Budding now has small amount of host cell membrane has sialic acid residue that NA cuts i Does not kill cell immediately Reservoirs and Transmission 0 O O O 0 Birds pigs dogs humans etc Mostly hostspecific Probably natural reservoir birds all A strains occurin birds infections asymptomatic transmitted by respiratory and GI tract B type influenza seasona flue only humans Transmission through inhalation of aerosols Disease Influenza A flu O URT damage 0 May spread to LRT but not usually other body parts so no actual stomach flu 0 Symptoms fever malaise headachefatigue 47 days I Most caused by immune system 0 Major complications secondary bacterial infections caused by URT damage esp s pneumoniae 0 Variation and impact on disease 0 10 major subtypes ofNA ex H5N 1 H1N 1 H2N2 many variations 0 Antigenic Drift Virus evolution rapid because of re plicase errors 0 Antigenic Shift virus may reassort due to segmented genome bcvirus can mix amp match I May pandemicoutbreaks I Ex bird influenza human influenza in pig new strain to spread to human 0 Treatment and Control 0 Antiviral drugs inhibit uncoating inhibit NA resistance is increasing 0 Annual vaccine I Mix strains predicted to be frequent in next year I Prepared in eggs chemically inactivated injected 0 Newervaccines also available FluMist nasal spray oflive vaccine attenuated strains Streptococcus Pneumoniae o Gram Firmicute quotpneumococcusquot o Nonmotile no catalase different from staphylococcus o Obligate hemolacticfermentation o Aerotolerant o Capnophile prefers increased C02 0 Abundant polysaccharide capsule o Reservoirhumans 0 Cells fragile and don t survive long outside 0 Colonizes nasopharynx in up to 60 of population mostly wo symptoms 0 May compete with other microbes ex vs S aureus 0 Disease often from selfinfection after URTdamage o Commensal pathogen o Pneumococcal pneumonia lungs 0 Cells resist phagocytosis neutrophil recruitment damage mainly from immune response 0 Damage may promote bloodstream invasion 0 Treatment and control 0 Occurs when sufficient bacteria reach LRT Strong inflammatory response Symptom onset rapid fever chills coughing chest pain Up to 2 million deaths peryear majorinfant mortality Usually treatable with antibiotics resistance increasing Vaccine targets most common capsular types subunit vaccines OOOOO Microbes of the Gastrointestinal GI Tract o Metabolicfunction food digestion waterabsorption neurological function gutbrain access immune function 0 Most immune cells in GI tract talkto immune system 0 Antimicrobialfunctions 0 pH 0 tight barriers bnepithelialcells o movementofsaliva o Majorimmune presence 0 GI contents 0 Prod Of mucusAMP lg o rapidturnoverofepithelialcells o Layers of GI tract 0 Mucus outer where most microbes live 0 Epithelial Layer 0 Immune Cesinner o Roles ofGl Microbiota 0 Metabolic I degrade plant polysaccharides and mucus I synthesize vitamins I microbial metabolites in blood I Production ofSCFA 0 Preferred energy source for intestinal epithelial cells IEC o IEC in germfree mice severey energy depreived o Regulate gut motility o Signalingmoleculestoimmunesystem o Microbes affect metabolitelevels all parts of body 0 Many good but may also be bad 0 Protective I feedepithelialcells butyrate I colonizationresistance I nutrient competition I productionofantimicrobials o Immune educate immune system 0 Gut microbiota and dysbiosis o Nonoptimal gut microbiota may affect health 0 Possible contribution to IBS colon cancer Celiac s etc 0 Ex dysbiosis link bn microbes TMAO trimethylamine oxide and CVD o lfdiet increases in red meat increased of chemicals microbes use I Microbes produce TMA can be further metabolized by FMO e nzyme to TMAO highercholesterol o ProbioticsandPrebiotics o Probiotics Pure cultures microbial strains yield measurable health benefit with testingin controlled trials 0 Prebiotics food you feed your probiotic microbes o Synbiotics prebiotics probiotics together Major Pathogens of GI Tract o Generallyfromingestedfoodwater o Avoids killingfrom stomach grow in intestines I Cystform and acid tolerance important 0 Often animalshumans only hosts fecal ora transmission 0 Sometimes normal microbiota can cause disease commensal pathogens 0 Ex clostridium difficile enterococcus spp 0 Types ofGI pathogens Gut Pathogen gt cell 1 2 3 BodyTissues 1 Extracellular 2 Growth inside 3 Use GI Tract as portal gt Pathogens toxins C6 or invaSion other parts Ex vibrioand clostridium 0 Effects 0 Disrupt wate rflow across epithelial cells 0 Affect health of epithelial cel Is 0 Engage immune system 0 Outcomes 0 Change in waterin feces diarrhea 0 Inflammation 0 Chronic or re peat infections malabsorption of nutrients growth retardation developmental delays 0 Treatment and control 0 Oral rehydration therapy I Electrolyte replacement with solution of glucose sodium chloride sodium bicarbonate and potassium chloride Antibiotics maymay not be useful may minimize shedding or alter microbiota Fecal transplant may be successful Few vaccines available 0000 Control oftransmission I Clean watersupply filtration chlorination 0 Control of wastes human animals wastes contact with irrigation water crops animal producers Vibrio Cholerae o Gram Proteobacterium 0 Very fast growing can double in 10 minutes 0 Reservoir 0 Lives in marine waters variable can live on algal cells or animals 0 Freeliving don t need human host 0 Transmissionandinfection o Contaminated waterand food 0 Not acidtolerant 0 Small intestine attaches to intestinal epithelial cells and produces toxins cholera toxin 0 Grows rapidly does NOTinvade extracellular pathogen 1 Normal normal ion concentration movement of Nano net Cl39 movement 2 Colonization amptoxin production a AB toxin Active amp Binding b Bindstoepithelialcels injectsAcomplexintocell c Modifies protein alters cell function 3 Na movement blocked net Cl movement to lumen 4 Massive water movement to lumen osmosis to alleviate concentration diarrhea 0 Outcomes o Watery diarrhea amp dehydration large amounts May die win 24 hours of initial symptoms V cholera released in large quantities leads to pe rsonperson Many mild or asymptomaticinfections are shedders oflive bacteria Best treatment oral rehydration OOOO Clostridium Difficile o Gram Firmicute o Intestinal colonist o Obligate anaerobe endospores 0 Part of normal microbiota if biota disrupted clostridium can grow to high levels 0 Antibioticinduced disturbance 0 Was nosocomial now also in community 0 Infection 0 Tch and Tch disrupt epithelial barrier cause cell death and induce inflammation 0 Cause pseudomembrane accumulation of dead cells in intestinal lining 0 Outcomes 0 Range from asymptomaticconditions gt mild diarrhea gt severe psuedomembrane bowel perforation sepsis shock death o Recurrent infections common in severely affected people 0 Susceptibleto vancomycin and metronidazole o Fecal transplants promising
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