Microbiology - Bacteriology - Morphology of Bacteria PDF

Medical microbiology: is the study of causative agents of infectious diseases of humans and their reactions to such infections. In other words, it deals with etiology, pathogenesis, laboratory diagnosis, specific treatment and control of infection (immunization). Microbiology: the study of...

Medical microbiology: is the study of causative agents of infectious diseases of humans and their reactions to such infections. In other words, it deals with etiology, pathogenesis, laboratory diagnosis, specific treatment and control of infection (immunization). Microbiology: the study of organisms too small to be seen without magnification. Micro - too small to be seen with the naked eye Bio - life logy - study of ◾ Microorganisms include: 1. Bacteria. 2. Fungi. 3. Algae. 4. Parasite {protozoa &helminthes (worms) } 5. Viruses.  Basic Branches of Microbiology 1. Bacteriology: The study of bacteria. 2. Mycology : The study of fungi. 3. Phycology: The study of photosynthetic eukaryotes. (Algae- Seaweed). 4. Parasitology: The study of parasites which include pathogenic protozoa certain insects and helminth worms. 5. Virology- The study of viruses, non-cellular particles which parasitize cells.  Morphology (Shape) of Bacteria 1. Cocci shaped-bacteria – spherical/ oval shaped …………..……. ‫كروية‬ 2. Bacilli shaped-bacteria – rod shaped …................................…… ‫عصوية‬ 3. Spiral shaped-bacteria – spiral shaped …............................…… ‫حلزونية‬ A. Vibrio – curved or comma shaped......... ‫ضمات مثل الضمة او مثل حرف الواو‬ B. Spirillum – rigid spiral forms ….........…….... ‫حلزونية لكن جدار الخلية صلب‬ C. Spirochetes – flexible spiral forms …......…. ‫حلزونية لكن جدار الخلية صلب‬ D. Helical forms– short spiral forms …........................…. ‫حلزونية لكن قصيرة‬ 4. Filamentous shaped-bacteria …………......................................… ‫خيطية‬ 1. Cocci shaped-bacteria – spherical/ oval shaped Arrangement of Cocci 2. Bacilli shaped-bacteria – rod shaped Arrangement of Bacilli 4. Spiral shaped-bacteria 4. Filamentous shaped-bacteria Actinomyces  Structure of Bacterial Cell 1. Cell wall a. Outermost layer, encloses cytoplasmic membrane. b. Peptidoglycan is responsible for the rigidity of the bacterial cell wall and for the determination of cell shape. 2. Cytoplasmic (Plasma) membrane a. Thin layer, separates cell wall from cytoplasm. b. Acts as a semi-permeable membrane: controls the inflow and outflow of metabolites. 3. Cytoplasm Colloidal system of variety of organic & inorganic solutes. Cytoplasmic Components a. Ribosomes: place of protein synthesis (70 S). b. Mesosomes. c. Nucleoid: single, circular double stranded DNA (one chromosome).  Additional Bacterial Cell Structures 1. Plasmid: extra-nuclear genetic elements consisting of DNA. Its carry some genes responsible for antibiotic resistance. 2. Capsule: Protects bacteria from lytic enzymes. Inhibits phagocytosis. 3. Flagella: Long filamentous surface appendages. Organs of locomotion. 4. Fimbriae (Pili): Thin, hair like appendages on the surface of many Gram negative bacteria. Acts as organs of adhesion (attachment) - allowing bacteria to colonize environmental surfaces or cells. 5. Spores: a highly resistant resting stages formed during adverse environment (depletion of nutrients). b. Formed inside the parent cell, hence called Endospores. c. Very resistant to heat, radiation and drying and can remain dormant for hundreds of years. Capsule Arrangement of Bacterial Flagella 1. Monotrichous (Polar): singleflagellum at one pole. 2. Lophotrichous: tuft of flagella at one pole. 3. Amphitrichous: flagella at both poles 4. Peritrichous: flagella all over. 5. Amphilophotrichous: tuft of flagella at both ends Thank you