Introduction to Medical Microbiology PDF

Introduction to Medical Microbiology 1 Asst. Prof. Dr. Ayhan MEHMETOĞLU [email protected]  Basic concepts of microbiology, history Main differences between Learning microorganism groups Objectives...

Introduction to Medical Microbiology 1 Asst. Prof. Dr. Ayhan MEHMETOĞLU [email protected]  Basic concepts of microbiology, history Main differences between Learning microorganism groups Objectives Identifying prokaryotic and eukaryotic cell To know the general characteristics of bacteria, parasites, viruses and fungi 2 What is Microbiology? Microbes, or microorganisms are minute living things that are usually unable to be viewed with the naked eye. What are some examples of microbes? Bacteria, fungi, protozoa, algae, viruses are examples! Many are Some are beneficial pathogenic 3 3  Is the study of causative agents of infectious diseases of humans and their reactions to such infections. Medical microbiology It deals with etiology, pathogenesis, laboratory diagnosis, specific treatment and control of infection (immunization). 4  History of Microbiology Ancient diseases supernatural powers, gods, demons Egyptians used salt as an antiseptic. Hippocrates (460-377 BC) Experimental observation, method and research principles in the medical field He attributed the diseases to disturbances in the body's vital fluids and classified the diseases as acute, chronic, epidemic and endemic. 5  First steps Operators to clean their hands and nails Washing the wounds with hot water Applying some drugs around the wounds Miasma Theory Bad air causes diseases (Diseases are caused by toxic substances from the soil, from the swamp to the air) 6  Middle ages Hippocrates and Galen's views are widely accepted. Cancer identified, mercury compounds in parasitic diseases, Vinegar used as an antiseptic Girolamo Fracastoro 1546 : Contagious diseases are transmitted to healthy patients by germs, direct contact with the contamination and living beings can play a role in the contamination. Miasma theory Microbes theory 7  Spontaneous Generation (Abiogenesis) Wheat + cheese Mouse The stinking of meat Fly William Harvey Biogenesis Francesco Redi Redi Experiment living things generated of living things (1626-1697) 8  1860s: Joseph Lister used a chemical disinfectant to The prevent surgical wound Germ infections after looking at Theory of Pasteur’s work showing microbes are in the air, can Disease spoil food, and cause animal diseases. 9  Anton van Leeuwenhoek 1674 - 1st person to actually see living microorganisms （Leeuwenhoek）1632-1723 “wee animalcules” 10  1673-1723, Antoni van Leeuwenhoek (Dutch) described live microorganisms that he observed in teeth scrapings, rainwater, and EM peppercorn infusions. 11 1 1  Louis Pasteur (1822-1895) End of Spontaneous generation Role of microorganisms in fermentation reactions Pasteurization Sterilization Aseptic techniques Louis Pasteur considered the father of Modern Microbiology 12 13 Robert Koch 1843 - 1910 A German scientist Formulated the Bacteriological techniques Staining Methods Discovered the Mycobacterium and Vibrio cholera 14  Koch’s Postulates 1. A given organism must be present in every case of a given disease; 2. The microorganism can be isolated from (or demonstrated in) specimens associated with that disease state; 3. Inoculation of the isolate into susceptible animals produces a similar disease; and 4. The same organism that is associated with the initial disease state can be recovered from representative specimens from the experimentally infected animal. 15  Molecular Koch's postulates (1) The phenotype (sign or symptom of disease) should be associated only with pathogenic strains of a species. (2) Inactivation of the suspected gene(s) associated with pathogenicity should result in a measurable loss of pathogenicity. (3) Reversion of the inactive gene should restore the disease phenotype. 16 17  Microorganisms Microorganisms can be found in every ecosystem and in close association with every type of multicellular organism. (Microbiota) The role of microorganisms like bacteria, fungi, protozoa, helminths, and viruses in the initiation and spread of human diseases. Microorganisms that are harmful to humans, either by production of toxic compounds or by direct infection, are characterized as pathogens. 18 19 20  Important definitions Infection: The case in which microorganisms come in contact with the organism to cause disease. Infectious diseases: The diseases that occur as a result of infection. Pathogenicity: The ability of microorganisms to cause disease Virulence: The virulence of a microorganism is a measure of the severity of the disease it causes. 21  How infectious disease starts ? Colonization: That is, the establishment of proliferating microorganisms on the skin or mucous membranes). Except introduction of organisms directly into the bloodstream or internal organs. 22  Microbial colonization may result in: 1) Elimination of the microorganism without affecting the host 2) Infection in which the organisms multiply and cause the host to react by making an immune or other type of response. Infectious disease occurs when the organism causes tissue damage and impairment of body function. 23 Lippincotts_Illustrated_Reviews_Microbiology_ 3rd_Edition_by_Richard_A._Harvey_Cynthia_N au_Cornelissen_Ph.D 24  Host-Parasite Relationship The term refers to the relationship between the host and the parasite and the competition for supremacy that takes place between them. Disease should not be confused with infection; a person may be infected without becoming diseased. In biology, the relationship between two organisms is mainly in the form of symbiosis, defined as "life together", i.e., the two organisms live in an association with one another ". 25  Host-Parasite Relationship Neutralism: Two organisms living together, and neither is affected by that. Synergism: Sometimes, two (or more) microorganism may work together “team up” to produce a disease that neither could cause by itself. Symbiosis: Permanent association between two different organisms. 26 Types of Symbiotic Association: Mutualism Mutualism is a relationship in which both partners benefit from the association. Mutualism is usually obligatory, since in most cases physiological dependence has evolved to such a degree that one mutual cannot survive without the other. 27  Commensalism Commensalism: in which one partner benefits from the association, but the host is neither helped nor harmed. 28  Parasitism Parasitism: in which one of the participants, the parasite, either harms or lives at the expense of the host. Pathogenic organisms like bacteria, viruses, fungi protozoa and helminths. Pathogenic organisms may release toxins or cause mechanical injury, such as boring a hole into the host or digging into its skin or other tissues, stimulate a damaging inflammatory or immune response. 29  Prokaryotic Pathogens Whereas eukaryotic organisms All prokaryotic organisms are include fungi, protozoa, and classified as bacteria, helminths, as well as humans. Eubacteria, which include all bacteria of medical importance Archaebacteria 30 Lippincotts_Illustrated_Reviews_Microbiology_ 3rd_Edition_by_Richard_A._Harvey_Cynthia_N au_Cornelissen_Ph.D 31  Typical bacteria Most bacteria have shapes that can be described as either a rod, sphere, or corkscrew. Nearly all bacteria, with the exception of the mycoplasma, have a rigid cell wall surrounding the cell membrane that determines the shape of the organism. The cell wall also determines whether the bacterium is classified as gram-positive or gram-negative. 32  Typical bacteria External to the cell wall may be flagella, pili, and/or a capsule. Bacterial cells divide by binary fission. However, many bacteria exchange genetic information carried on plasmids necessary for establishment of antibiotic-resistance. 33  Atypical bacteria Atypical bacteria include groups of organisms such as Mycoplasma, Chlamydia, and Rickettsia that, although prokaryotic, lack significant characteristic structural components or metabolic capabilities that separate them from the larger group of typical bacteria. 34  Fungi Fungi are nonphotosynthetic, generally saprophytic, eukaryotic organisms. Some fungi are filamentous, and are commonly called molds, whereas others like yeasts are unicellular. Fungal reproduction may be asexual, sexual, or both, and all fungi produce spores. Pathogenic fungi can cause diseases, ranging from skin infections (superficial mycoses) to serious, systemic infections (deep mycoses). 35  Protozoa are single-celled, nonphotosynthetic, eukaryotic Protozoa organisms. Many protozoa are free-living, but others are pathogenic. Members of this group infect all major tissues and organs of the body ,intracellular or extracellular, in the blood, urogenital region, or intestine. Transmission is generally by ingestion of an infective stage of the parasite or by insect bite. 36  Helminths Helminths are groups of worms that live as parasites. They are multicellular, eukaryotic organisms with complex body organization. They are divided into three main groups: Tapeworms (cestodes) Flukes (trematodes) Roundworms (nematodes) 37  Viruses Viruses are obligate intracellular parasites that do not have a cellular structure. Rather, a virus consists of molecule(s) of DNA (DNA virus) or RNA (RNA virus), but not both, surrounded by a protein coat. A virus may also have an envelope derived from the plasma membrane of the host cell from which the virus is released. 38 39  Viruses contain the genetic information necessary for directing their own replication but require the host's cellular structures and enzymatic machinery. The fate of the host cell following viral infection ranges from rapid lysis releasing many progeny virions, to Viruses gradual, prolonged release of viral particles. Viruses cause a broad spectrum of diseases 40 Review of Medical Microbiology and Immunology, Fourteenth Editi, Copyright © 2016 by McGraw Dr. Ayham Abulaila 41 Review of Medical Microbiology and Immunology, Fourteenth Editi, Copyright © 2016 by McGraw Dr. Ayham Abulaila 42  Dr. Ayham Abulaila 43 Review of Medical Microbiology and Immunology, Fourteenth Editi, Copyright © 2016 by McGraw  References Murray, Patrick R., MEDICAL MICROBIOLOGY, EIGHTH EDITION ISBN: 978-0-323-29956-5 Lippincotts Illustrated Reviews Microbiology 3rd Edition by Richard A. Harvey Cynthia Nau Cornelissen_Ph.D Jawetz Melnick & Adelbergs Medical Microbiology Review of Medical Microbiology and Immunology, Fourteenth Edition by Warren Levinson, MD, PhD. www.cdc.com  For any question [email protected] 45