Microbiology Practical PDF
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Gulf Medical University, Ajman
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Summary
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