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Medical Microbiology (Biology of Small Organisms)

Medical Microbiology (Biology of Small Organisms). Major Topics Included in MAC 221. Bacteriology Virology Parasitology Mycology Immunology. Introduction To Mac 221:. Basic Immunology and Host Parasite Relationship Bacteria and Human Diseases caused by bacteria.

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Medical Microbiology (Biology of Small Organisms)

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  1. Medical Microbiology(Biology of Small Organisms) Major Topics Included in MAC 221 • Bacteriology • Virology • Parasitology • Mycology • Immunology

  2. Introduction To Mac 221: • Basic Immunology and Host Parasite Relationship • Bacteria and Human Diseases caused by bacteria. • Parasitology Parasite & Human Diseases • Virology – Virus & Human Diseases • Mycology – Fungi & Human Diseases

  3. Microbiology And The Patient Medical Microbiology – concerned with: • Aetiology (cause) • Pathogenesis (Mechanism of production of disease) • Laboratory Diagnosis • Treatment of infection • Epidemiology (spread, distribution, prevalence of infection in the community) • Control and prevention in community

  4. MIC has Close Link with: • Pathology • Medicine (clinical) • Surgery • Pharmacology and therapeutics • Preventive Medicine

  5. MIC has a Close Link with Curative Medicine in regard to: • Precise diagnosis • Rational treatment of microbial diseases Diagnosis of Bacterial infection done by: • Clinical • Laboratory Methods

  6. Laboratory Methods: Collection of specimens • Microscopy Stained Specimens Unstained Specimens • Culture • Identification of the organism • Tests for Antimicrobial agents serology • Demonstration of Abs

  7. Medical Students Need to Know Microbiology Especially Bacteriology • To Diagnose Bacterial infections successfully 2) To Treat

  8. Course Objectives • Basic understanding of immune system 2) Basic understanding of host-parasite relationship 3) Understandingof the pathogenesis 4) Understand the clinical features 5) Understand the Epidemiological features

  9. Course Objectives (Continued) 6) Understand the proper use of Clinical Lab. a) Specimen collection and handling b) Requesting appropriate tests c) Interpretation of results of Lab. tests • Correct selection, use, monitoring of anti-microbial therapy • Understand methods of prevention of infection e.g.Vaccine, chemoprophylaxis, hygiene, isolation etc.

  10. Diagram of Atypical Bacterial Cell

  11. Bacteria Unicellular, Microscopic, Prokaryotic Organisms, Multiply By Binary Fission. Comparison Between Bacteria And Fungi And Protozoa BacteriaFungi & Protozoa Type Prokaryotic Eukaryotic Chromosome One Multiple (Number) Nuclear Absent Present Membrane

  12. Comparison Between Bacteria and Fungi and Protozoa (Continued) BacteriaFungi & Protozoa Mitochondria Absent Present Ribosomes 70s 80s Sterols Absent (Except Usually In Mycoplasma) Present Cell Wall Rigid Layer Of No Peptido- Peptidoglycan Glycan (Absent In (In some cases Mycoplasma) cellulose present)

  13. Bacteria can be divided into: • Filamentous Bacteria (Actinomycete) Most capable of branching • True (Euobacteria): Divide by Binary Fission • Spirocheates: Divide by Transverse Binary Fission • Mycoplasma Which Lack Rigid Cell Wall • Ricketssiae, and Chlamydia which are strict Intracellular parasites Vibrio (coma shape) Cocci Bacilli (rods)

  14. Formal Rank Example Taxonomic Ranks ________________________________________________________________________________________________________________________ Kingdom Prokaryotae Division Gracilicutes Class Scotobacteria Order Eubacteriales Family Enterobacteriae Genus Eschirichia, Streptococcus, Staphylococcus, Streptococcus, Klebsiella Species coli Pyogenes aureus pneumoniae pneumonia

  15. Simplified Classification of Medically – Important Gram-positive Bacteria Arranged in Micrococcus Aerobes or clusters facultative Staphylococcus Anaerobes Cocci Arranged in Streptococcus chains Anaerobes Peptostreptococcus

  16. Simplified Classification of Medically – Important Gram-positive bacteria Sporing Bacillus Aerobes or facultative anaerobes Corynebacterium Non- Listeria sporing Lactobacillus Nocardia Mycobacterium RODS Sporing Clostridium Anaerobes Non- Actinomycosces sporing

  17. Simplified Classification Of Medically – Important Gram-negative Bacteria Aerobes Neisseria Cocci Anaerobes Veillonella

  18. Simplified Classification Of Medically – Important Gram-negative Bacteria Aerobes Pseudomonas Salmonella Shigella Klebsiella Proteus Escherichia Facultative Yersinia Anaerobes BACILLIBordetella Haemophilus Brucella Pasteurella Vibrio Anaerobes Bacteroids Fusobacterium Microaerophilic Camplylobacter

  19. Simplified Classification Of Medically – Important Gram-negative Bacteria Aerobes Leptospira Spirochaetes Anaerobes Borrelia Treponema Cell wall --- Mycoplasma deficient bacteria

  20. Diagram of Atypical Bacterial Cell

  21. External Structures I) Flagella Long Filaments a. Responsible for motility; b. Protein (Flagellin) similar to myosin of muscles c. Can be polar, Bipolar or Peritrichous Short Filaments a. Common pili Adhesion b. Sex pili Conjugation

  22. Capsule Present in Certain Bacteria. Water (2 %) solid Polysaccharide; occasionally protein e.g.Bacillus anthracis a. Inhibit Phagocytosis b. Antigenic

  23. Example Of Capsulated Bacteria a. Pneumococci b. KlebsiellaPolysaccharide Capsules c. Cl. perfringens d. Bacillus anthracisPolypeptide Capsules

  24. Flagella

  25. Bacterial Spores • Hardest part of bacteria • Contain calicum pectate • One spore = one negative bacteria • Can live for years Example: 1. Clostidia (Anaerobic) e.g. Cl. perfringens 2. Bacillus (Aerobic) e.g. B. anthracis

  26. CELL WALL - porous, permeable to low molecular weight (LMW) substances. • Found in Algae, fungi, plants and bacteria • Not found in animals Functions Of Cell Wall a.Confer rigidity upon bacteria b. Protects against osmotic pressure which can be 5-20 atmospheric pressure in bacteria c. Gives bacteria its shape d. Participates in cell division e. Gram staining characteristic

  27. Structures of Cell Wall Basic = mucopeptide (peptidoglycan) PEPTIDOGLYCAN = consists of a. N-acetyl mumaric acid (M) b. N-acetyl glucosamine (G) strands. Theses strands are linked by peptide side chains Peptide chain G M M G G M

  28. In AdditionGram +ve bacterial cell wall a Thick peptidoglycan layer (many layers) b. Teichoic acids (20% of cell wall weight) Gram –ve cell wall a. Thin peptidoglycan layer (1-2 layers) b. Out layer of lipopolysaccharide, phospholipids, lipoprotein c. Porins

  29. Diagrams Showing The Structure Of Bacterial Cell Walls

  30. Annual System • Bacteriology + Immunology = 50% = 50 marks Practical = 10 marks Mid term = 10 marks Final = 30 marks • Parasitology & Virology + Mycology = 50% = 50 marks Practical = 10 marks Mid Term = 10 marks Final Exam= 30 marks

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