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CHAPTER 1 WHAT IS MICROBIOLOGY AND WHY IS IT IMPORTANT? © WHO / TDR / Crump Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 The Importance of medical and most populous group of Microorganisms organisms and are found everywhere on the planet play a major role in recycling essential elements source of nutrients and some carry out photosynthesis benefit society by their production of food, beverages, antibiotics and vitamins causative agents of some important diseases Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 What is Microbiology? generally defined as the study of organisms too small to be clearly seen by the unaided eye (i.e., microorganisms) these organisms are relatively simple in their construction and lack highly differentiated cells and distinct tissues Members of the Microbial World procaryotic cells lack a true membranedelimited nucleus eucaryotic cells have a membraneenclosed nucleus, are more complex morphologically and are usually larger than procaryotic cells Procaryotes most are single-celled most have peptidoglycan in cell wall can survive broad range of environments most are non-pathogenic and play major role in nutrient recycling Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …….. Eucaryotes animals, plants and eucaryotic microorganisms microorganisms include protists (unicellular algae, protozoa, slime molds and water molds) and fungi most are larger than procaryotic cells …….. Viruses acellular smallest of all microbes (smallest is 10,000 times smaller than a typical bacterium) Importance of Microorganisms first living organisms on planet live almost everywhere life is possible more numerous than any other kind of organisms global ecosystem depends on their activities influence human society in many ways WHY IS THIS IMPORTANT? Microbiology is more relevant than ever in today’s world. Infectious diseases are a leading health-related issue, especially in a society where the elderly population is increasing. New infectious diseases continue to emerge and be identified all the time. Microbiology impacts every facet of daily life Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 Discovery of Microbes Antony Van Leeuwenhoek (1632-1723) first person to observe and describe microorganisms accurately Developed early microscope First to observe microbes:“animalcules” …….. Pasteur Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 …….. Pasteur • Pasteur laid the foundation of aseptic techniques, techniques that prevent contamination by unwanted microbes. These techniques are based on Pasteur’s idea that microbes can be killed by heat and that procedures can be designed to inhibit the access of airborne microbes to nutrient environment. • He disapprove the idea that microorganisms spontaneously generated from non-living matter. Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 The Golden Age of Microbiology (1857-1914) •Many disease producing organisms were discovered •Microbial metabolism studies undertaken •Microbiological techniques refined •A better understanding of the role of immunity and ways to control and prevent infection by microbes Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 The Role of Microorganisms in Disease • was not immediately obvious • establishing connection depended on development of techniques for studying microbes • once established, led to study of host defenses - immunology Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 Recognition of the Relationship between Microorganisms and Disease Agostini Bassi (1773-1856): showed that a disease of silkworms was caused by a fungus M. J. Berkeley (ca. 1845): demonstrated that the great Potato Blight of Ireland was caused by a water mold Heinrich de Bary (1853): showed that smut and rust fungi caused cereal crop diseases Louis Pasteur (1860s - 80s) : showed that the pébrine disease of silkworms was caused by a protozoan Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 Aseptic techniques …….. Pure Culture Technique Phases of antibiotic development Pre Antibiotic Era-No antibiotic Antibiotic era - penicillin “New” Diseases Resurgence of “old” diseases Microbial resistance to drugs Emergent Diseases and the Post-Antibiotic Era Experts agree that decades of antibiotic use and abuse have contributed to the emergence of antibioticresistant organisms in both hospital and community settings. Antibiotic era We have all heard of the Pre-Antibiotic Era, prior to the 1940’s when millions of people died from common bacterial infections because antibiotics were not used to treat them. In the last 50 years we have enjoyed the luxury of knowing that bacterial infections can almost always be cured by using antibiotics. We are now in the Antibiotic Era. Post-Antibiotic Era As we enter the 21st Century, we are gradually slipping into the Post-Antibiotic Era, a time when antibiotics no longer work because bacteria have become resistant to all the antibiotics. The change will not come as suddenly as the start of the Antibiotic Era, because the change to antibiotic resistant germs has been slow, up until now. New strains are rapidly developing In the next 5-10 years we will start noticing the change much more dramatically. OVERVIEW Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 CASE STUDIES FROMillustrate DAILYhow LIFE The following case studies microbiology is part of our everyday lives: ( Ref. pg3-7) Special Delivery Ivan Goes to Chicago Hamburger Havoc The Hospital Can Be Dangerous Did You Wash Your Hands Mary, Mary, Quite Contrary It’s For the Birds Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 Microbiology: A Clinical Approach, by Tony Srelkauskas © Garland Science ISBN: 978-0-8153-6514-3 MICROBIOLOGY & INFECTIOUS DISEASE Today microbiology is mentioned frequently in the news. It affects many facets of our daily lives, including: The air we breathe The food we eat The hospitals where we go for treatment of illness and injury The natural disasters which sometimes occur without warning Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 THE RELEVANCE OF MICROBIOLOGY TO HEALTH CARE There has always been disease. For generations, little could be done to treat or prevent disease. Advances in public health awareness lessened the effects of infection. Infectious disease utilizes a large percentage of health care. Health care professionals need to understand how pathogens cause disease. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …THE RELEVANCE OF MICROBIOLOGY TO HEALTH CARE The discovery of antibiotics began to prevent serious infection. Vaccination and better sanitation practices reduced the incidence of infectious diseases. For a time, most infectious diseases were thought to be under control. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …THE RELEVANCE OF MICROBIOLOGY TO HEALTH CARE Diseases once thought to be under control are reappearing Pathogens are showing increasing resistance to antibiotics. New diseases are emerging and organisms that were thought to be harmless have been discovered to cause disease in certain circumstances. Interest in bioterrorism has progressed from fiction to fact. A fundamental understanding of microbiology has never been more relevant. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 INFECTIOUS DISEASE Only a tiny fraction of microorganisms cause infections. A microorganism that causes an infection is called a pathogen. Only a fraction of pathogens affect humans. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …INFECTIOUS DISEASE The potential of a pathogen to cause disease is referred to as its degree of virulence. Pathogens can be categorized based on their degree of virulence. Many bacteria and some fungi are part of the normal microbial flora of the body. They naturally colonize the skin and mucosal surfaces. Most of the time, these organisms are completely harmless. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …INFECTIOUS DISEASE Some of these organisms provide important products and services to the body. Under certain circumstances, these organisms become pathogenic. When this happens, the organisms are called opportunistic pathogens and typically possess a mild degree of virulence. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ...INFECTIOUS DISEASE Some pathogens are always highly virulent. Highly virulent pathogens are always associated with disease. Most pathogens can be looked at from the following 3 perspectives: Epidemiology Pathogenesis Host defense Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 EPIDEMIOLOGY Epidemiology is the study of factors determining the frequency and distribution of disease. In epidemiology, pathogens are studied by how well they meet the five requirements of infection: Entry (Get in) Establishment (Stay in) Defeat the host defense Damage the host Be transmissible Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ...EPIDEMIOLOGY In epidemiology, pathogens are classified by the transmission mechanisms they use. Such as: Air Food or water Insect vectors Person-to-person contact Pathogens can also be classified according to their geographic distribution Some are found worldwide, others are restricted to certain geographic areas. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ...EPIDEMIOLOGY Providing the best care for infected individuals and protection of others involves a clear understanding of the 5 requirements for infection. Knowing how an organism gains entry and how it spreads are vital to care for infected individuals It allows for the implementation of strategies to limit spread. It also helps in understanding of the spread of disease. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ...EPIDEMIOLOGY Epidemics are caused by a variety of factors, including the following: Poor socioeconomic conditions Ignorance of how infections occur Poor hygiene Natural disasters Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 PATHOGENESIS Virulence factors are required for a pathogen to do the following: Persist in the patient Cause disease Escape or defeat host defenses Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ...PATHOGENESIS Pathogens employ a variety of methods to accomplish infection. Bacterial pathogens can: Produce digestive enzymes Produce toxins Viral pathogens can kill the host cells. Sometimes, damage associated with an infection is due to over active host defenses. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …PATHOGENESIS Symptoms can be associated with particular types of infection: Coughing – respiratory infection Diarrhea – digestive infection Nervous system dysfunction – central nervous system Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 HOST DEFENSE Infection is a complex and competitive struggle. It can be characterized as pathogens versus host defense. The outcome of this struggle depends on the success or failure of the host defense. Failure of the host defense = infection! Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ....HOST DEFENSE Many pathogens have developed methods to defeat host defenses. Some directly attack host defenses Some change their looks (a form of camouflage) Some hide Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 TREATMENT OF INFECTIOUS DISEASES Many potent and successful tools are available to defeat infection. These include: Antibiotics Disinfectants and antiseptics Antibiotics are toxic chemicals and therefore must act selectively. They must kill the disease-causing microorganisms but not harm the patient. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …TREATMENT OF INFECTIOUS DISEASES Treatments are easier for bacterial infections than for fungal and viral diseases. Fungal cells are very similar to human cells so very few chemicals are selectively toxic. Viruses are intracellular parasites so either: They must be attacked before entry into a host cell. or The infected host cells must be killed to kill the virus. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …TREATMENT OF INFECTIOUS DISEASES The best treatment of disease is prevention. Prevention involves public health measures and immunization. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 …TREATMENT OF INFECTIOUS DISEASES Public health measures include: Disinfection of water supplies Monitoring food supplies Proper hygiene and sanitation Proper waste removal and treatment Insect and pest control Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 ..TREATMENT OF INFECTIOUS DISEASES Immunization requires that we understand immune mechanisms and that we design vaccines that will successfully stimulate protection. Immunization also requires: Public health control of the immunization of children Design and development of new vaccines An ability to ensure the safety of vaccines Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 MICROBIOLOGY ISN’T JUST ABOUT INFECTIOUS DISEASE Some microbes are very beneficial to humans as they are able to: Recycle vital elements in soil. Convert elements in the environment into usable forms. Return CO2 into the atmosphere. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 BIOREMEDIATION AND RECYCLING Microbes have been routinely used for bioremediation since 1988. Microbes can be used: To recycle waste water during sewage treatment. To clean up and decontaminate toxic waste including chemical and oil spills. In the production of enzymes that are subsequently used in cleaning solutions. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 INSECT CONTROL Bacteria are extensively used to control pests. They can be applied as part of crop dusting. Bacterial genes can be engineered into the plants themselves. Using bacteria in these ways is seen as being safer than using chemicals. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 BIOTECHNOLOGY Bacteria and viruses are often used for many new technologies. Bacteria can be engineered to produce drugs. Viruses can be used for gene therapy strategies. Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3 Bibliography Microbiology, A clinical Approach -Danielle Moszyk-StrelkauskasGarland Science 2010 http://en.wikipedia.org/wiki/Scientific_method http://www.brighthub.com/science/medical/articles/21169.aspx ( L Pasteur & theory of Biogenesis) Microbiology: A Clinical Approach Approach,©byGarland Tony Srelkauskas Science © Garland Science ISBN: 978-0-8153-6514-3
