Microbiology Practical PDF
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This document provides information about various bacteria, including their characteristics, tests for identification, and uses in different contexts. The information covers Gram-positive and Gram-negative bacteria, describing their morphology, properties and distinguishing features, useful in contexts like medical analysis.
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Gram Positive cocci Staphylococcus Staphylococcus Epidermidis Gram positive cocci, grape like Coagulase Test: Negative clusters Novobiocin: Sensitive Hemolysis:...
Gram Positive cocci Staphylococcus Staphylococcus Epidermidis Gram positive cocci, grape like Coagulase Test: Negative clusters Novobiocin: Sensitive Hemolysis: non hemolytic 1. Coagulase Test: Staphylococcus Saprophyticus a. Positive: Staphylococcus Coagulase Test: Negative Novobiocin: Resistant Hemolysis: Non- Hemolytic Staphylococcus Areus Coagulase Test: Positive Novobiocin: Sensitive Hemolysis: Beta Hemolysis Aureus b. Negative: S. Epidermidis, S. Haemolyticus, S. Saprophyticus 2. Catalase Test: Positive Streptococci Streptococcus Pneumoniae Pneumonia, meningitis Sample: sputum, laryngeal swab, CSF, Pus 1. Catalase Test: Negative 2. Hemolysis: a. Alpha Hemolysis: incomplete hemolysis (Strep. Viridans, Strep. Alpha Hemolytic Blood Agar Pneumoniae) Sensitive to Optochin b. Beta Hemolysis: Complete hemolysis (Strep. Pyogenes, Strep Agalactiae) c. No hemolysis: colorless (Enterococcus Fecalis) Streptococcus Pyogenes Causes sore throat (pharyngitis) Specimen collection: throat swab, pus, blood Gram positive cocci in chains Beta Hemolytic colonies Positive Quellung Reaction Bacitracin Test: Sensitive Enterococcus Fecalis Gram negative cocci Gram positive cocci in Neisseria Meningitidis pairs and short chains Causes meningitis Specimen: CSF, blood, nasopharyngeal swab Gram negative diplococci Non-hemolytic blood agar Negative catalase test Stuart’s Medium Black colonies Oxidase and Catalase test positive Neisseria Gonorrhoeae Catalase and oxidase test: Causes gonorrhea (STD) Positive Specimen: urethral swab in mean, cervical swab in women Transport media: Stuart’s and Amies Transport medium Thayer Martin Medium Gram Positive Bacilli Gram Negative Bacilli Clostridia Escherichia Coli Diarrhea, Pseudomembrane Laboratory diagnosis: Stool culture on selective medium Toxin demonstration by enzyme immunoassay, PCR etc. Causes UTI, Septicemia and Gram positive bacilli with Pyogenic Infections spores Specimen: urine, stool, pus, wound swab For UTI collection: catheter specimen urine, suprapubic aspiration, midstream urine MacConkey Agar: pink colonies lactose fermentation Robertson Cooked Meat Positive Indole test - Red ring Anaerobic Jar Klebsiella Pneumoniae Pseudomonas Aeruginosa Causes Pneumonia: UTI, nosocomial infections, predisposing factors include chronic respiratory tract alcoholism, diabetes mellitus, infections, ear infections, chronic bronchopulmonary infective endocarditis & skin disease infections for burn patients UTI, Nosocomial Infections, Nutrient Agar Pyogenic Infections: abscesses, Meningitis, Septicemia Gram negative bacilli capsulated MacConkey Non Lactose fermenting MacConkey Agar: large mucoid pink colonies (capsulated bacilli) Oxidase Test Positive NEGATIVE Indole Test Helicobacter Pylori Mycobacteria and Spirochetes Acute gastritis, peptic ulcer Mycobacterium Tuberculosis Warthin Starry Silver Stain Causes tuberculosis Specimen: sputum, laryngeal swab, bronchial washings Acid Fast Staining Positive Catalase & Oxidase test Lowenstein-Jensen medium Urease Positive test Non-invasive Tests: ○ Urea breath test & serology Spirochetes Detection of Viral Antigens & Treponema pallidum Antibodies Causes Syphilis HIV Bright spirochete against Elisa dark bg Silver staining (dark brown spirochete against yellow bg) Rapid Test/ Immunochromatography test (ICT) Non-specific test: Rapid Plasma Reagin test Confirmatory test: Specific test: T pallidum WESTERN BLOT Hemagglutination Assay (TPHA) Fungal infections Aspergillus Candida Albicans Lactophenol Cotton Blue Gram positive budding (LPCB) mount yeast cells with pseudohyphae Green velvety colonies / black granular colonies White pasty colonies like cottage cheese Parasites Plasmodium Falciparum Malaria Transmitted by anopheles mosquitoes Ring shaped trophozoites Gram positive budding yeast cells Gametocyte - crescent shape Ascaris lumbricoides (Round worm) Transmitted by ingestion/ feco oral route Causes gastrointestinal disturbances Laboratory diagnosis ○ Detection of eggs in stool ○ Adult worms in stool Eggs : ○ oval in shape with irregular surface ○ Bile stained (yellow color
