Microbiology for Nurses - Topic 1 Lecture Notes PDF

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Microbiology for Nurses Topic 1: Overview of Microbiology (Jan 8th, 2020) Learning Objectives: List and Differentiate the major characteristics of the organisms that are studied in Mircobiology Bacteria - very small - single celled (unicellular) - prokaryotic: genetic material not enclosed in a nuclear membrane - cell walls composed of peptidoglycan - reproduce by binary fission - come in several shapes - bacillus = rod - coccus = spherical - spiral = corkscrew or curved - filamentous

Fungi *Eukaryotic: genetic material is enclosed within a membrane-bound nucleus - examples: - yeasts - molds - mushrooms

Bacterial pathogens - see notes for examples Yeasts: - unicellular, oval shaped - some beneficial - important in research - pathogenic yeasts e.g Candida albicans causes yeast infections of mouth & vagina. Occurs in patients with HIV-AIDS and after antibiotic tx Molds: - filamentous fungi - widespread - each filament is called a hypha - filaments form visible mass called mycelium - reproduce by spores - some cause spoilage of foods (e.g bread, fruit) - some produce antibiotics and other drugs (e.g penicillin)

Protozoa

Helminths: Parasitic Flatworms or Roundworms

Viruses

Pathogenic Fungi: - some fungi cause disease or mycoses - chronic infections difficult to treat - 5 type of infections: systemic, subcut, cutaneous (athletes foot, ringworm), superficial & opportunistic - unicellular - eukaryotic - found in water, moist environments - motile using: cilia, flagella, pseudopods - some cause disease (e.g. malaria, toxoplasmosis, giardiasis) - multicellular, eukaryotic animals - parasitic, belong to two phyla: 1. Platyhelminthes (flatworms) – flukes, tapeworms 2. Nematoda (roundworms) - very small, seen only using an electron microscope - acellular (not cellular) - nucleic acid core with DNA or RNA - protein coat - may have lipid envelope - must replicate within a living host cell (parasites)

- use host machinery to reproduce - infect: bacteria (bacteriophages), plants & animals (including humans) - important viruses of medical significance: influenza virus, hepatitis virus A,C, human immunodeficiency virus (HIV), oncoviruses, Ebola virus Define what Mircobiology is. Microbiology - Microbiology is the study of living organisms that individually cannot be seen with the naked eye. - organisms referred to as microorganisms or microbes - examples of microorganisms that are studied: -> bacteria, viruses, fungi, protozoa, multicellular animal parasites etc Where do we find microorganisms? - are found everywhere! - air, tables, floors, soil, water - in and on us: skin, throat, gut (normal microbiota) What are normal microbiota? - microorganisms that normally reside on or in the human body without causing disease Have many benefits! - aid in digestion - some make vitamins for us - e.g. vitamin K, some B vitamins - can protect us from disease BUT: some can cause opportunistic infections - can cause damage when there is uncontrolled proliferation - e.g. antibiotic treatments - immunocompromised (e.g. HIV) - or get into the wrong place - in the gut, they are not harmful but if they get into the urinary system (for example) they can be harmful and cause urinary infections

Describe some of the destructive and beneficial actions of microorganisms Benefits of Microorganisms - most mircoorganisms are harmless! - many are beneficial: Energy/ Environment - biofuel production; e.g CH4 (methane) ethanol - bioremediation: using microbes to clean up toxic pollutants (oil, solvents, pesticides, heavy metals, etc.) - sewage treatment (water recycling) Agriculture - insect pest control by microorganisms: e.g. Bacillus thuringiensis produces a toxin that is active against insect pests Food Industry - production of many foods -e.g. beer, chocolate, bread Pharmaceutical Industy - production of antibiotics, anti-cancer, immunosuppressive agents - production of enzymes used as digestive aids Biotechnology - production of recombinant human hormones (e.g insulin), blood proteins, and immune modulators - gene therapy Destructive Actions of Microorganisms - some microbes can invade a susceptible host and cause infectious diseases - microbes that cause disease are called pathogens - the ability of a pathogen to cause disease depends on the disease-producing properties of the microbe and the host’s ability to ward disease (resistance) - Health-associated infection (HAI): infection acquired while receiving treatment for other conditions at a healthcare facility - a concern with HAI are antibiotic resistant infections Understand the system of nomenclature (naming) used for organism and be able to distinguish a genus from a specific epithet (species). Naming Microorganisms - bacteria, fungi, protozoa (but not viruses) - named using the latinized binomial system of genus and specific epithet (species) - the genus name is the first name and is always capitalized - the species name follows and is not capitalized - names italicized or underlines - once written can be abbreviated example: Escherichia coli or

genus name

epithet (species) name

E. coli...