هذا العمل ل يغني عن الرجع الساسي للمذاكرة Lecture 6 Gram Posi0ve & Negave Bacteria • Important • Term • Extra explanaon • Addi0onal notes Objectives • Know the general basic characteristics of bacteria. • Differentiate between gram positive and gram negative bacteria characteristics. • Know the classes and groups of gram positive bacteria and gram negative, cocci and bacilli (rods). • Know the common identification characteristic of these groups. • Know the common infections and diseases caused by these organisms and the antibiotics used for their treatment. Gram Stain • Developed in 1884 by the Danish physician Hans Christian Gram • An important tool in bacterial taxonomy (the branch of science concerned with classification), distinguishing so-called Gram-positive bacteria, which remain colored after the staining procedure, from Gram- negative bacteria, which do not retain dye and need to be counter- stained. • Can be applied to pure cultures of bacteria or to clinical specimens. Type Gram positive cell wall Gram negative cell wall • Thick, homogenous sheath of • Outer membrane containing peptidoglycan 20-80 nm thick lipopolysaccharide (LPS) • Tightly bound acidic • Thin shell of peptidoglycan Consist of polysaccharides, including • Periplasmic space (between the teichoic acid and lipoteichoic cell wall & plasma membrane) acid • Inner membrane • Cell membrane Retain crystal violet and stain Lose crystal violet and stain PINK stain PURPLE or BLUE or RED from safranin counterstain counterstain Safraninٍ تتفظ هذه البكتيريا بلونها بعد أن حتى ل تنسى تذكر أن: تصبغت بصبغة جرام مهما تعرضت الزعفران لونه أحمر و نوع هذه لي مادة كيميائية، فهي كالكرستال البكتيريا تتصبغ باللون الحمر قوية وصلبة Gram Stain لحظ كيف اختفى اللون البنفسجي وأصبحت بل لون (Decolorization) Or acetone Gram Stain Gram Negative Baciili(rods) E.Coli ( Pure culture ) Gram Negative Cocci With Pus Cells Neisseria gonorrhoeae (Smear of urethral pus) - Clinical specimen Gram Positive Bacteria Occurring optionally in response to circumstances rather than by nature. Staphylococci Aerobic / facultative Streptococci Anaerobic Cocci Enterococcci Anaerobic Peptostreptococci Bacteria Bacteria Cornybacterium Listeria Aerobic / facultative Positive Positive Anaerobic Nocardia Bacilli Latobacillus , Gram Gram Bacillus Anaerobic Clostridium Gram Positive Bacteria Gram Positive Cocci (Aerobic / facultative Anaerobic) 1. Staphylococci * Catalase-positive * Gram-positive cocci in clusters Coagulase-positive Coagulase negative Staphylococcus epidermidis Staphylococcus aureus Normal flora in the skin Most important pathogen Staphylococcus saprophiticus Gram Positive Bacteria 2. Streptococci * Catalase-negative * Gram-positive cocci in chains or pairs Streptococcus Viridans Streptococcus pyogenes streptococci pneumoniae An example of Group β- Occur in the mouth as Causes: Hemolytic streptococcus normal flora. - Meningitis (Most clinically important of this - Sinusitis group) - Otitis - Pneumonia Pathogenesis : Pharyngitis (most common) Causes endocarditis * Endocarditis is an Cellulitis (acute inflammation of subcutaneous tissue) infection of the inner Rheumatic Fever lining of your heart Characterized by: Fever, (endocardium)] Migrating polyarthritis , carditis and immunologic cross reactivity Acute Glomerulonephritis: Edema, hypertension, hematuria antigen-antibody complex deposition Gram Positive Bacteria 3. Enterococci Example Enterococcus faecalis Gram positive bacteria A-Non spore forming Bacilli B-Spore forming Aerobic/facultave anaerobe Anaerobic Aerobic spore forming most important is Bacillus anthracis ,that Gas gagarene • C. tetani , Cause: Tetanus. C.tetani causes anthracis • C. perfringens, Cause:Gas -Bacillus anthracis has • gangarene. the only bacterial capsule that’s made of • C. botulinum , Cause: botulism. and C. botulinum C. tetani POLYPEPTIDE. • Descending weakness-->paralysis both anaerobes produce • diplopia, dysphagia-->respiratory the same toxin but failure REMEMBER that tetani’s • C. diphtheriae, Cause: Fever, toxin inhibits the inhibitory pharyngi0s, cervical LAD (disease of impulses in the brain otherwise botlulinum’s the lymph nodes). toxin will inhibit the release thicK, gray, adherent membrane of ACH. sequelae-->airway obstruc0on, myocardi0s Gram- Negative Cocci • Neisseria gonorrhoeae – The Gonococcus • Neisseria meningidis(it is considered as poten.al pathogen in the oropharynx) – The Meningococcus • Both Gram-negave intracellular diplococci • Moraxella catarrhalis Gram- Negative Rods • Enteric Bacteria they ferment sugars most important are; – E. coli – Salmonella – Shigella – Yersinia and Klebsiella pneumoniae – Proteus Gram- Negative Rods • FasMdious GNRs – Bordetella pertussis – Haemophilus influenzae – Campylobacter jejuni – Helicobacter pylori – Legionella pneumophila • Anaerobic GNRs – Bacteroides fragilis (It is one of the anaerobes that resist penicillin so instead we should use Metronidazole for its treatment). – Fusobacterium Oxidise posi0ve comma shaped and also Oxidise posi0ve non i.e. they do not fermentave most ferment sugars e.g:. important is Vibrio -Pseudomonas that causes infec0on in cholerae that causes Immunocompromised paents cholera which is a disease -Oxidise negave non fermentave e.g. characterized by severe Acinobacter species diarrhea and dehydraon Non-Gram-stainable bacteria Unusual gram-positives Unusual gram-Negative -Spirochaetes • Mycoplasmas -Obligate intra-cellular – Smallest free-living organisms bacteria – No cell wall – M. pneumonia, M. genitalium Online Quiz Pull my pili! Fine! Just click HERE Videos Gram Posi0ve Bacteria vs Gram Negave Bacteria Gram Staining Bacterial characteris0cs - Gram staining Books that could help you v Lippincott’s Illustrated Reviews : Microbiology Second Edition. v Lippincott’s Microcards Microbiology Flash Cards Third Edition. We do things better Girls Team • Lamya Alsaghan • Nojood Alhaidri Boys Team • Monera Alayuni • Ali Alzahrani • Alanoud AlOmair • Khalid Sharahily • Shahad Alenezi • Ahmad Alzahrani • Aisha Al-Sabbagh • Zeyad Alsalem • Bodour Julaidan • Muhammad Dossary • Noura AlTawil • Meshal Alhazmy • Deema AlFaris • Hamzah Alfiar • Sara Al-Hussein • Suha Alenezy • Lafah AlsuKait [email protected] • Dalal Alhuzaimi • Reema Allhaidan @microbiology435 Contact us! http://ask.fm/microbiology435 إن أصبنا فمن ال عز وجل، وإن أخطأنا فمن أنفسنا والشيطان .