Pathogenic Microorganisms 222 PHARM Lecture Notes PDF

Pathogenic Microorganisms 222 PHARM Introduction to Microbial World 1/3/2025 2  Objectives 1.Define microorganisms and scopes of microbiology 2.Understand microbial world and microbial classification 3.Differentiate between prokaryotes...

Pathogenic Microorganisms 222 PHARM Introduction to Microbial World 1/3/2025 2  Objectives 1.Define microorganisms and scopes of microbiology 2.Understand microbial world and microbial classification 3.Differentiate between prokaryotes and eukaryotes 4.Provide types, shapes and arrangement of microorganisms under microscope 1/3/2025 3  WHAT IS MICROBIOLOGY? ❑Micro - too small to be seen with the naked (unaided) eye ❑Biology= study of living things ❑Bio=life; ology= study of ❑Microbiology is the science deals with the study of very small living organisms (microorganisms; M.O.) that cannot seen by naked eye ❑Medical Microbiology is the science deals with the study of M.O. causing infection/disease ❑Most microbes (95-97%) are beneficial 1/3/2025 4  THE SCOPE OF MICROBIOLOGY PROKARYOTES BACTERIA MICROBIAL WORLD LIVING ALGAE ORGAANISM FUNGI EUKARYOTES PROTOZOA ACELLULAR VIRUSES HELMINTHESIS ❑The infectious agents belong to Bacteria, Fungi, Protozoa, Helminths, Viruses ❑Viruses acellular, non-living agent, infectious agents or infectious particles 1/3/2025 5 Classification of living organisms A. According to the type of the cell B. According to domains C. According to kingdoms 1/3/2025 6  A. ACCORDING TO TYPE OF CELL PROKARYOTIC & EUKARYOTIC CELLS 1/3/2025 7  EUKARYOTE VS PROKARYOTE Item Prokaryote Eukaryote Examples Eubacteria, Archaebacteria Fungi, protozoa, algae Level of organization Unicellular Uni- & multi-cellular Cell size Small ~ 1-10 m Large ~ 10-100 m Peptidoglycan Present Absent Cell membrane Sterols Absent except mycoplasma Present Nucleus Nucleoid (primitive) True nucleus Nuclear membrane and Absent Present nucleolus Organelles Absent Present No of chromosomes Single circular lack histones >1 linear with histones Size of ribosome 70S 80S Mode of division Binary fission Meiosis & mitosis Respiration via Cytoplasmic membrane Mitochondria 1/3/2025 8  B. According to domains ❑3 domain (Woese et al. 1990) ❑Prokaryote includes 2 domains 1. Archaebacteria: do not have peptidoglycan 2. Eubacteria: cell wall containing peptidoglycan ❑Eukaryote includes one domain 3. Eukarya domain includes ❑Animals, plants, fungi, etc. 1/3/2025 9 C. According to Kingdoms 6 kingdoms Woese & Fox, 1977 7 Kingdom: Thomas Cavalier-Smith, 2000 1- Archaea 1- Archaebacteria 1- Archaebacteria Three Domains 2- Bacteria 2- Eubacteria 2- Eubacteria 3- Animalia 3- Animalia 4- Plantae 4- Plantae 3- Eukarya 5- Eumycota (Fungi) 5-Eumycota 6-Protozoa 6- Protista 7-Chromista (Algae) 1/3/2025 10  BINOMIAL NOMENCLATURE SYSTEM OF TAXONOMIC CLASSIFICATION ❑Taxonomic categories include domain, kingdom, phylum, class, order, family, genus and species ❑All organisms have Binomial Nomenclature ❑Binomial nomenclature includes genus and species 1.Genus is a category of biologic classification ❑Example: Staphylococcus 2.Species represents a different type of microorganisms ❑Staphylococcus aureus ; Staphylococcus epidermidis 1/3/2025 11 BINOMIAL NOMENCLATURE ❑Scientific name may be descriptive or honor a scientist ❑Staphylococcus aureus describes the clustered arrangement of the cells (staphylo-) & the golden color of colonies (aur-) ❑Escherichia coli honors the discoverer, Theodor Escherich & describes its habitat–colon ❑The first letter of the Genus is always capitalized ❑Species is written in lowercase letters; never capitalized ❑Genus can be abbreviated- Species is never abbreviated ❑Genus & Species are italicized ❑Escherichia coli, E. coli; Staphylococcus aureus, S. aureus 1/3/2025 12  BACTERIAL SHAPES ❑Shape determined by its rigid cell wall ❑Bacteria are monomorphic but some are pleomorphic ❑3 basic shapes 1.Bacilli ❑Straight rod shaped ❑Coccobacilli (short rods) ❑Fusiform: bacilli with tapered ends ❑Curved (vibrios): short, slightly curved rods ❑Filamentous: bacilli that occur in long threads 1/3/2025 13 BACTERIAL SHAPES 2. Cocci (Spherical or oval shaped) 3.Spiral (sprilla.sprillum): Helically curved Rods ❑Flexible, undulating e.g. spirochetes 1/3/2025 14  BACTERIAL ARRANGEMENT of COCCI 1. Diplococci (in pairs): Cells divide in one plane ❑remain attached in pairs e.g. Streptococcus pneumoniae 2. Streptococci (in chains): Cells divide in one plane ❑remain attached to form chains e.g. Streptococcus pyogenes 3. Tetrads: Cells divide in 2 planes & remain in groups of four 4. Sarcinae (in eights): Cells divide in 3 regular planes, producing cuboidal arrangement of cells & remain in groups of eight 5. Cluster/staphylococci: ❑Cells divide in 3 irregular planes & producing “bunches” of cocci 1/3/2025 15  BACTERIAL ARRANGEMENT of BACILLI ❑Divide only across their short axis a.Single: ❑Most bacilli appear as single rods b.Diplo/pairs/Diplobacilli: ❑Appear in pair after division c.Chains: Streptobacilli d.Palisades 1/3/2025 16 1/3/2025 17 Thank You