BIO 208 - Microbiology - Unit 4 - Lecture 20 - Microbial ...



Unit 4 – Survey of the Role of Microbes in Health and DiseaseIn Lecture 20 we will talk about several aspects of microbial water quality – to aid in your preparation, review of material from Lab 18 where it applies to lecture today.Microbial Aspects of Water QualityClean and safe drinking water – global perspectiveIn the U.S. water quality is regulated by __________________________________________Microorganisms from the intestinal system are shed with feces and can be transmitted via the ____________________________ route (E. coli and pathogens like Salmonella)Quality Control - Water Quality Testing – Testing for likelihood of fecal contaminationIndicator Organisms – Indicator of potential fecal contamination - Ideally an indicator organism: is present whenever intestinal pathogens of concern are presentis present only when there is real danger of intestinal pathogens being presentis present in greater number than the pathogens to provide a margin of safetysurvives in the environment at least as long as the pathogens dois easy to detect (such as the membrane filtration test you did in lab)Commonly Used IndicatorsTotal coliforms – GNR that ferment lactoseProblem – Fecal coliforms – a subset of coliforms that are thermotolerantE. coli and enterococci (species of streptococci that are found in the intestines) – most specific indicators of recent fecal contamination –1. Wastewater TreatmentWastewater – comes from domestic or industrial effluents (effluent is the outpouring of water)Domestic H2O = Q. Why does wastewater need to be treated?A. Because it is:1. 2. 3. Q. What are the goals of wastewater treatment?A.1. 2. Q. What happens to domestic wastewater? A. Wastewater treatment consists of a combination of physical and biological processesPrimary – physical - screen out large junk, settle sludge + liquid Secondary – microbial - nutrient load, organics (BOD)Liquid – aerobicSludge – anaerobic aerobic respirers (heterotrophs + chemoautotrophs)fermenters and anaerobic respirersOxidation of complex organics CO2Fermentation of complex organics CO2 + CH4Liquid - disinfect with chlorine, aerate,Remaining sludge – land application as fertilizer QC (count E. coli in water usinge.g., membrane filtration like you did in lab)discharge to body of water.2. Drinking Water TreatmentQ. What are the goals of drinking water treatment?A.1. decrease turbidity2. eliminate taste and odor3. reduce chemicals4. remove potentially pathogenic microbesIn the US, drinking water usually comes from Steps in a Typical Water Treatment Facility1. Source – water from source moves to a sedimentation basin where sand and gravel are removed. Turbidity will be decreased (clarity improves)2. Clarify – water moves next to a clarifier where chemicals are added to create a “floc”. Flocs 3. Filter – clarified water is filtered to remove the flocs containing organics and particles including microorganisms.4. Disinfect- to kill any remaining microorganisms - chlorination is most common disinfectant of treated water, kills most microbes w/in ____________ min. (some communities use ozone).Problems w/ chlorination residual chlorine in water cysts of protozoan pathogens like Giardia and Cryptosopridium 5. Quality control (QC) – determine counts of coliform bacteria remaining in the treated drinking water. Must be _______________________6. Distribute – 3. Protection of Great Lakes Recreational WaterThe Great Lakes have more than ____________ miles of coastlineMichigan has over __________ miles of coastlineThe Michigan coastline has ________ public access beachesQ. How does fecal material gets into beach water A. 1. 2.3. 4. Human source fecal contamination is In Michigan, beach water quality is regulated by _______________________________________.The threshold ____________________________________________ – if thresholds are exceeded, swim advisories may be posted or beaches closed.Lectures 21-26 will introduce you to aspects of medical microbiology – good stuff for MCAT, PA admissions test, etc.Medical Microbiology1. Disease Transmission and Epidemiology – Chapter 14These notes should be reviewed prior to the class on Disease Transmission and Epidemiology. We will NOT go over this material in class (we are doing something very different today), but it is essential for your understanding of what we will be covering in class.Disease - change from a state of healtha. Terminology related to infectious diseasesEtiology – the cause of a diseaseEtiological agent –microorganism that causes the disease (same as pathogen)Pathogen – microorganism that is capable of causing diseasePathology – the study of diseasePathogenesis – the manner in which a disease develops and progressesInfection – invasion or colonization of the body by a pathogenIncubation – the time interval between infection and the first appearance of signs and symptomsSymptom – A subjective indication of a disease (something you, the patient, experiences), such as feeling hot, tired, achy, nauseousSign – An objective finding, usually detected on physical examination, from a laboratory test, or x-ray (etc.) that indicates the presence of abnormality or disease, such as elevated body temperature (fever), increased respiration rate, elevated white blood cell count, fluid in the lungs, etc.Epidemiology – the study of disease in populationsa. Terminology related to epidemiologyEndemic = disease that is constantly present in a population (e.g., measles)Epidemic = an unusually large number of cases (every winter we see an epidemic of Influenza)Outbreak = a cluster of cases in a short time period (currently, avian influenza in southeast Asia)Pandemic = an epidemic that spreads worldwide (what we fear may happen with avian influenza)b. Reservoirs - where pathogens persist, a continual source of the organism that can fuel casesi. human reservoirs of disease – the primary reservoir of most diseases of humans is the human body itselfsymptomatic – a person exhibiting signs and symptoms of disease and is capable of infecting othersEx. someone with norovirus gastroenteritis (nausea, vomiting)asymptomatic carriers – a person that is not exhibiting signs and symptoms, apparently healthy, but infected and infectious to others.Ex. people infected with gonorrhea or herpes may be asymptomatic but are still infectiousii. nonhuman reservoirs of diseasezoonoses - diseases of animals that can be transmitted to humansEx. rabies, salmonellosisiii. environmental reservoirssoil (botulism, tetanus), water (Legionnaire's, cholera), etciv. hospitals and hospital personnel as reservoirs, esp. of antibiotic resistant microorganismsc. Transmission – how pathogens are spreadi. by contacta) direct contact – also called person-to-person contact- when 1 person physically touches anotherEx. touching (MRSA infections), sexual contact (STIs)b) indirect - via inanimate objects = fomites – some examples include door knobs, telephones, computer keyboards, tv remotes, etcEx. cold viruses and Influenzac) droplet transmission – in droplets coming from the respiratory system (sneezes, coughs)Ex. tuberculosis, Influenza, SARSii. by food, water, or fecal contaminated material (fecal-oral) gastrointestinal pathogens incl. waterborne pathogensingestioncross-contamination of food preparation materialsEx. salmonellosis, shigellosis, choleraiii. airborne (similar to droplet transmission)Ex. anthrax, histoplasmosisiv. by vectorsa) mechanical - vector transfers microbes from one host to another.Ex. housefly, fleasb) biological - vector is required in microbe's life cycleEx. mosquitoesv. nosocomial – acquired as a result of being hospitalized, from the hospital environment or contact with hospital personnel or other patients.Significant problem!!! 5-15% of all hospitalized patients will develop a nosocomial infection!Significant or Interesting Human DiseasesKey to Understanding Infectious Diseases:Microbes are as old as the planetHumans evolved under the selective pressure of microbesMicrobes see our bodies as just another habitatIn all the vast diversity of microbial life, only the smallest fraction of microbes are capable of causing illnessFor any infection with a potential pathogen, there are a wide variety of possible outcomesDiseases of the SkinGeneral backgroundMain pathogens of the skinStaphylococcus aureusStreptococcus pyogenesGPC, cat + GPC, cat -Skin diseases caused by S. pyogenesGroup A Strep (GAS)1. impetigo2. erysipelas – infection of dermal layer of skin3. invasive GAS - approximately 9,000-11,500 cases in the U.S./yr resulting in 1,000-1,800 deaths.Two most severe, least common:necrotizing fasciitis (infection of muscle and fat tissue)streptococcal toxic shock syndrome (a rapidly progressing infection causing low blood pressure/shock and injury to organs such as the kidneys, liver and lungs).The class pick --*Disease - *Agent – *Virulence factors (what factors does this strain have that other strains do not, that makes this one capable of causing disease)*Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – Diseases of the Nervous SystemGeneral backgroundNervesBrainThe class pick --*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – Diseases of the Cardiovascular or Lymphatic SystemsGeneral backgroundThe class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – Diseases of the Respiratory TractSystem – upper versus lowerMain Diseases & Pathogens of Upper Respiratory Tract (URT)Defenses of URT– very well defended - multiple defenses - chemical, immunological, and microbial.NoseRhinitis100% viralRhinovirus(cold)Coronavirus, AdenovirusThroatPharyngitis70% viralAdenovirus(sore throat)EBV, Herpes, Coxsackie30% bacterialS. pyogenes, C. diphtheriae, H. influenzaeMain Diseases & Pathogens of Lower Resp. Tract (LRT)Defenses of the LRT – defenses diminish with depth into the lower respiratory system - ciliated epithelial cells, cough reflex, alveolar macrophagesTracheaWhooping coughbacterialBordetella pertussisInfluenzaviralInfluenza virusBronchiAcute bronchitis50% viralAdenovirus50% bacterialMycoplasma, S. pneumoniae, H. influenzaeLungsAcute infectionsPneumoniabacterialS. pneumoniae (a.k.a pneumonococcus)viralAdenovirus, Influenza virusRespiratory DistressviralHantavirus, SARSChronic infectionsTuberculosisbacterialM. tuberculosisfungalAspergillus, HistoplasmaExample of an Acute Lower Respiratory Infection: InfluenzaWe will talk about:seasonal flupandemic flu*Disease - Influenza - “Flu” *Agent - Influenza virus (Orthomyxoviridae); enveloped RNA virus3 types infect humans (C, B, A - arranged least to most significant)Influenza type A - Responsible for regular outbreaks, including pandemics. Influenza A viruses also infect domestic animals (pigs, horses, chickens, ducks) and some wild birds, especially shorebirds and waterfowl. Influenza A viruses, which cause more severe human illness, are further categorized into subtypes on the basis of two surface antigens: hemagglutinin (H) and neuraminidase (N). Among all Influenza viruses (human and animal) there are 14 major H proteins and 9 major N proteins forming 144 different combinations of H+N.* Virulence1. kills cells of the trachea (may result in secondary bacterial infections of the respiratory system (acute ear infections and pneumonia, both due to Streptococcus pneumonia are the most common complications of influenza infection)2. makes a protein that inhibits the immune system1. Seasonal Flu* Transmissionvia respiratory droplets released when an infected person coughs or sneezes.enters body thru mucous membranes of eyes, nose, mouth.binds to receptors on non-ciliated cells of the respiratory epithelium and then enters those cells via receptor-mediated pinocytosisincubation 1-4 days, average = 2 days.contagious from 1 day prior to symptoms (before you know you are sick) and for another 5 days after symptoms develop.* Clinical PictureUncomplicated influenza illness is characterized by the abrupt onset of constitutional and respiratory signs and symptoms [Constitutional - fever, myalgia (= body aches), headache, malaise (= overall feeling of unwell). Respiratory - nonproductive cough, sore throat, and rhinitis].Influenza illness typically resolves after a limited number of days for the majority of persons, although cough and malaise can persist for >2 weeks.The risks for complications, hospitalizations, and deaths from influenza are higher among persons aged >65 years, young children, and persons of any age with certain underlying health conditions.* TreatmentSome few, specific anti-viral drugs: Amantadine and Rimantadine - These drugs inhibit one of the viral matrix proteins that are used to get viral RNA into the cytoplasm of the target cell. They work against A types only and resistance to these drugs evolves quickly. Zanamivir (Relenza?) and Oseltamivir (Tamiflu?) - These drugs block the neuraminidase and thus inhibit release of virus progeny from the infected cell. Spraying zanamivir into the nose or inhaling it shortens the duration of disease symptoms by 1-3 days.Yearly flu vaccine (more below)Frequency20-50% of American population infected and 10-20% with symptomatic illness every year.Morbidity and MortalityIn US, 114,000 hospitalizations (>57% in people under age 65) and ~40,000 deaths/year – due to secondary bacterial infections and also primary influenza pneumonia, where the Influenza virus infects cells of the lungs in addition to the trachea.***Special topic of importance *** Why is it you can get influenza multiple times? (in theory you are susceptible every year!)Influenza virus is an RNA virus and its genome is made up of 8 RNA segments (a segmented genome is unusual).During replication the RNA is copied into RNA by an RNA polymerase. RNA polymerase has no proof-reading ability; it makes mistakes (i.e., produces mutations).These mutations cause changes in the surface proteins (the H or the N).Point mutations = a mutation in the RNA genome caused by one wrong RNA nucleotide base in the RNA sequence - will produce a slight, slight alteration in the surface protein. Antibodies (specific to H and N surface proteins) that your body produced to fight previous influenza infections do not recognize these slightly altered surface antigens very well, so your immune response is delayed, you become ill.This gradual change in the surface protein over time is called antigenic drift responsible for yearly, seasonal epidemics.There are several different types of influenza viruses circulating and different variants within virus types, and the same type of flu virus does not necessarily circulate each year. A person's immunity to the surface antigens reduces the likelihood of infection and severity of disease if infection occurs. If someone was infected with the Fujian strain of Influenza A (H3N2) that predominated last season, they are likely to have some natural immunity that will give them protection if they are exposed to the Fujian strain or a closely related H3N2 strain again this season, but no or little immunity to an unrelated strain.Frequent development of antigenic variants through antigenic drift is the basis for seasonal epidemics and the reason for the usual incorporation of > 1 new strains in each year's influenza vaccine (see table at end of lecture).2. Pandemic FluWhen flu illness occurs worldwide is referred to as pandemic flu. Pandemic flu occurs when the human population has no or limited immunity to an influenza virus because either the H or N surface protein is entirely new. Pandemic strains of influenza are created by a genetic event referred to as recombination.Recombination - Two different Influenza strains with different H and N antigens co-infect the exact same host cell. During packaging of viral progeny, the 2 strains will exchange an entire segment of RNA, which will result in a tremendous change in the surface protein. This abrupt change in surface protein is called antigenic shift responsible for pandemics.The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – For Your Information – additional information on Influenza virus and Influenza diseaseHow Influenza viruses are named: Ex. Influenza A/Singapore/6/86/H1N1:TYPEof influenza TOWNwhere first isolated NUMBERof isolatesisolated YEAR of isolation TYPE of H and NASINGAPORE686(H1N1)Composition of the Trivalent (= 3 flu strains) Vaccine Last 10 yearsSeasonH1N1H3N2Type B02–03A/New Caledonia/20/99A/Moscow/10/99B/Hong Kong/330/0103–04A/New Caledonia/20/99A/Moscow/10/99B/Hong Kong/330/0104–05A/New Caledonia/20/99A/Fujian/411/02B/Shanghai/36/0205–06A/New Caledonia/20/99A/California/7/04B/Jiangsu/10/0306-07A/New Caledonia/20/99A/Wisconsin//6705B/Malaysia/2506/04Influenza A/New Caledonia/99 was discovered and characterized by former CMU student Luke Daum, who now owns his own company called Longhorn Vaccines and Diagnostics. He is an international expert on Influenza.07-08A/Solomon Islands/3/26A/Wisconsin/67/05B/Malaysia/2506/0408-09A/Brisbane/59/07A/Brisbane/10/07B/Florida/4/0609-10A/Brisbane/59/07A/Brisbane/10/07B/Brisbane/60/0810-11A/California/7/09A/Perth/16/09B/Brisbane/60/08A/California/7/2009 (H1N1) is the pandemic strain that the media called “swine flu”11-12A/California/7/09A/Perth/16/09B/Brisbane/60/08The World Health Organization began in February to hold meetings to determine the composition of the 2012-2013 vaccine.Recent flu pandemicsYearHN typeStrainName of pandemic1580?first Influenza pandemic of recorded history1874 (H3N8)? 1889-90(H2N2)?Asiatic (Russian) Flu pandemic1900(H3N8) ?1918-20(H1N1)?”Spanish” Flu pandemic1933Influenza viruses were finally discovered 1940US military began the first Influenza vaccinations1957-58 (H2N2) A/Singapore/57"Asian" Flu pandemic 1968-69 (H3N2) A/Aichi/68"Hong Kong" Flu pandemic 1976-77 (H1N1)A/New Jersey/76"Swine" Flu – turned out to be a false scare2009(H1N1)A/California/093,900 deaths in U.S. in 1st 6 months.Since 1977, Influenza A (H1N1) and Influenza A (H3N2) viruses have been in global co-circulation. In 2002, Influenza A (H1N2) viruses that probably emerged after genetic recombination between (H3N2) and (H1N1), viruses began circulating widely, causing an increase in morbidity and mortality, but not a true pandemic.Avian Influenza (= Bird Flu)Bird flu is caused by avian influenza viruses. These flu viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, and among birds the virus is transmitted in the feces, but avian influenza is usually not fatal to wild birds. However, it is very contagious among birds and can make some domesticated birds (chickens, ducks, and turkeys) very sick and kill them.The risk from bird flu is generally low to most people because the viruses occur mainly among birds and do not usually infect humans. However, during an outbreak of bird flu among poultry (domesticated chicken, ducks, turkeys), there is a possible risk to people who have contact with infected birds or surfaces that have been contaminated with excretions from infected birds. Several cases of human infection with bird flu viruses have occurred since 1997, the most recent outbreak began in 2003. In October 2003, an epidemic of influenza in chickens began sweeping through several countries in the Pacific Rim (Vietnam, Thailand, Japan, China, South Korea, Cambodia). The virus is H5N1. The H5 molecule is common among bird influenza viruses but has not been seen on flu viruses that cause human epidemics. As a glance at the tables above will show, humans have had long experience with infections and vaccines by both H1 and H3 flu viruses. But the human population has absolutely no immunity against any H5 viruses. Clinical Picture - Symptoms of avian influenza in humans have ranged from typical human influenza-like symptoms (fever, cough, sore throat, and muscle aches), to eye infections, pneumonia, severe respiratory diseases (such as acute respiratory distress syndrome), and other severe and life-threatening complications.Mortality - currently 63%. Sexually Transmitted Infections (STI = STD = VD)MMWRTABLE II. Provisional cases of selected notifiable diseases, United States.2011Reporting AreaPopulationHepatitis BSyphilisGonorrheaChlamydiaMichigan10,071,8228024312,20747,003U. S.312,856,0002,39912,325291,2621,272,762What all STIs have in common:Transmission – direct mucosal contact with infected individualAsymptomaticCan be acquired multiple timesHaving one makes it much more likely you will have/get othersCan cause infertility and other permanent complicationsPrevention – Abstinence – the only guaranteeMonogamyLatex condomsRegular screening – all sexually active women should be screened for STIs every 6 months!The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention – Infectious Disease of the Gastrointestinal (GI) TractDigestive system overviewCDC estimates that each year ~ 1 in 6 Americans (or 48 million people) gets sick, 128,000 are hospitalized, and 3,000 die of food borne diseases. Focus Syndrome - Gastroenteritis = inflammation of stomach & intestines - extremely common – symptoms include primarily diarrhea; sometimes nausea, vomiting, crampy abdominal pain – caused by a diverse assortment of bacterial, viral, and protozoan pathogens.General mechanisms by which microbes cause disease in the GI:A. Produce toxinsB. Adhere to and damage intestinal microvilliC. Invade intestinal epithelial cellsA. Diseases due to toxin production:1. Toxin production only (no colonization of intestines) = Bacterial Food Poisoningbacteria need not enter the bodythey secrete toxins into the food that you ingestthese toxins aren’t destroyed by heatingExample organisms that cause food poisoningBacillus cereus, Clostridium botulinum (6 cases in 2010), Clostridium perfringens, Staphylococcus aureus.Toxin contaminated foods do not look, smell, or taste bad!The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention of food borne disease at end of lecture.2. Colonization of intestines followed by toxin production – Vibrio choleraeThe class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – B. Disease due to microbes that adhere to, enter, and damage intestinal microvilli – Shigella, E. coli O157:H7, Campylobacter, Rotavirus and Norwalk virus (of cruise ship fame), Entamoeba histolytica. The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – C. Disease due to microbes that adhere to and then invade across intestinal epithelial cells; may spread to deeper tissues – Salmonella, Hepatitis A, Reovirus, Enterovirus.The class pick –*Disease - *Agent – *Virulence factors - *Transmission – *Clinical picture – Treatment –Frequency –Mortality – Prevention and Control of Food borne IllnessCareful food production, handling of raw products, preparation of finished foodsNear Future Industry AdvancesChlorinating drinking water sources for food animalsSanitary slaughter and meat processingIrradiation of raw productsAt homeWash hands (w/ soap, 20 sec)Thaw in refrigerator or microwaveDon't cross-contaminate cooked w/rawWash fruits & veggies - even pre-washedWash knivesWash countertops, cutting boards, etc. in dilute bleachClean sponges dailySeparate towelsPay attention to "use-by" datesDon't buy "bad" cansImmediately refrigerate leftovers - shallow (less than 2") - less than 40?F ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download