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MVST 1B (Fach) / BOD practical (Lektion)
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- Reverse passive haemagglutination of AB-coated RBC’s Test for presence of antigen (e.g. human antibody in murder example) Antibody bound to RBC → agglutination
- ELISA for presence of human antibody Well coated with antibody → bind Ag → enzyme-linked second antibody
- Agglutination inhibition pregnancy test hCG attached to latex beads hCG antibody causes agglutination inhibited by exposure to excess hCG-antigen → no agglutination in pregnant women, when hCG is present
- Diffusion precipitation in gel Compare patterns: lines of non-/identity IgG, Alb, HS
- Titration of haemolytic activity of complement Serial dilution of complement → Minimal Haemolytic Dose
- Immunodiffusion → analyse / compare patterns of non-/identity lines
- Plaque forming cells Antibodies from B cell bind to antigen on RBC's and cause complement-mediated lysis
- Complement fixation test Test for presence of antibody Serial dilution of serum Incubate serum with Ag → add complement (3 MHD's) → add RBC's Result: Inhibition of lysis if antibody is present Controls RBC's + complement → should lyse Ag + RBC's + complement → Ag itself should not inhibit lysis serum + RBC's + complement → immune complexes (SLE, complement deficiency, current infection) in serum that activate complement?
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- Determination of ABO blood groups Antibody to A,B antigen → coagulation; codominant expression Test patient's cells against α-A, α-B antibodies Cross-test patient's serum against A, B, AB, O cells
- Direct antiglobulin test (Coombs test) αTest for non-agglutinating IgG-anti-RhD on neonatal RBC’s Incomplete antibodies → don't lyse, don't agglutinate (electrostatic repulsion, too few / distant binding sites to cross link complement, ragged surface) Pathology due to destruction of RBC's by macrophages / NK's in the spleen, NO complement Result Agglutinate washed Rh+ RBC's via α-human globulin Unwashed cells: α-human globulin mopped up by excess free IgG's
- Assay and serological identification anti-measles, anti-HSV antibody
- antiviral drugs (aciclovir) Different plaque densities w/ and w/o aciclovir. Acycliv guanosin analoge → chain terminator; activation by viral protein kinases (TK)
- T4 bacteriophage replication cycle data handling mean burst size multiplicity of infection pfu titre Poisson distribution --
- Titration of influenza by haemagglutination via HA → sialic acid, not biologically relevant Serial dilution of virus → Haemagglutinating titre
- Poliomyelitis Dilated vessel Perivascular cuffing of leukocytes replacement of motorneurones by granulomas
- Herpes zoster Necrosis, cell fusion, nuclear changes, loss of adhesion nuclear inclusion body - dene central core seperated from nuclear membrane
- Vaccinia Thickened / ulcerated rabbit cornea Paranuclear eosinophilic inclusion bodies mitotic figures → epidermal proliferation due to virus specific epidermal growth factrs
- Molluscum contagiosum Lesion of the epidermis, caused by pox virus Large eosinophilic cytoplasmic inclusion bodies
- Rabies Cytoplasmic Negri bodies
- Cytomegalovirus "Owl-eye" inclusion bodies in the nucleus
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- Virus neutralisation assay Titration of anti-influenza-antibody by inhibition of agglutination Serial dilution of serum → HaemAgglutination Inhibition titre: last well to inhibit agglutination
- MacConkey's plate Bile salts → permissive only for enteric organisms Red on low pH (lactose fermenters E. coli, Ent. faecalis), colourless else
- CLED plate Cysteine Lactose Electrolyte Deficient Urine samples, to avoid proteus mirabilis swarming Bromothymol blue → yellow for lactose fermenters (E. coli, Ent. faecalis)
- Nagler reaction Clostridium perfringens α-toxin (lecithinase) Neutralizing antibody to prevent reaction: egg yolk → insoluble diglyceride (opaque)
- ELEK plate Phage dependent diphtheria toxin Diffusion → precipitation of antigen-antibody complex
- Lancefield grouping For streptococci, based on characteristic carbyhydrate surface antigens Strep pyogenes → group A
- Salmonella Commensal skin, Pathogenic most areas VERY OPAQUE CREAM colonies Catalase positive, Coagulase Positive Gram Positive Cocci FACULTATIVE ANAEROBE Cells single, pairs or irregular cluster
- Analytical Profile Index Sequence of reactions, specific pattern can be looked up → E coli, salmonella, pseudomonas, proteus
- Albert's stain Corynebacterium → polyphosphate granules
- Anti-streptolysin O (strep pyogenes) Titration by toxin neutralisation neutralising AB in serum of exposed patients Serial dilution of patient's serum Inhibition of lysis of horse RBC's
- Hot Malachite Green stain Clostridium spores
- Catalase test Staph's positive, Strep's negative opposite ends of capillaries tube Positive test: Liberation of O2 (bubbling) from hydrogen peroxide H2O2
- Coagulase test Staph aureus positive Staph epidermidis negative Coagulase enzymes to coagulate lyophilised rabbit plasma Positive test: fibrin polymer ~ veil of protein
- Oxidase test Neisseria oxidase positive
- Deep wound Staph aureus Staph epidermidis Clostridium perfringens
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- Throat swab Strep pneumoniae Corynebacterium diphtheriae Neisseria pharyngis
- Faecal swab E. coli Salmonella Ent. faecalis
- Urethral smear Neisseria gonorrhoeae
- Abdominal surgical wound Salmonella Clostridium perfringens Bacteroides fragilis
- Staph aureus Commensal skin, Pathogenic most areas VERY OPAQUE CREAM colonies, larer than staph epidermidis Catalase positive, Coagulase Positive Gram Positive Cocci FACULTATIVE ANAEROBE Cells single, pairs or irregular cluster
- Staph epidermidis Commensal skin VERY OPAQUE WHITE colonies, smaller then Staph aureus Catalase positive, Coagulase Negative Gram Positive Cocci FACULTATIVE ANAEROBE Cells single, pairs or irregular cluster
- Strep pyogenes Throat infections MEDIUM colonies COMPLETE (BETA) HAEMOLYSIS Gram Positive Cocci FACULTATIVE ANAEROBE Ovoid/round Cells single, pairs or chains Lancefield group A
- Strep pneumoniae Pneumonia and meningitis MEDIUM colonies Greenish incomplete haemolysis Gram Positive Cocci, capsule stain FACULTATIVE ANAEROBE Ovoid/round cells; single, pairs or chains
- Enterococcus faecalis Gut commensal WHITE-CLEAR EDGE colonies Non-haemolytic Red on MacConkey’s, yellow on CLED Gram Positive Cocci FACULTATIVE ANAEROBE Ovoid/round Cells single, pairs or chains
- Neisseria pharyngis Commensal throat Gram Negative Cocci Mostly diplococci
- Viridans streptococcus Dental carries TINY colonies Greenish incomplete haemolysis Gram Positive Cocci FACULTATIVE ANAEROBE Ovoid/round Cells single, pairs or chains
- Neisseria gonorrhoeae Pathogenic genital mucosa Gram Negative Cocci Mostly diplococci Oxidase positive
- Corynebacterium diphtheriae Upper respiratory tract Gram Positive Bacilli, Albert’s Stain → polyphosphate granules AEROBE ELEK plate for phage dependent toxin
- Clostridium tetani Gram positive rods, may swarm, anaerob
- Clostridium sporogenes Wounds “gas gangrene“ "Medussae” colonies Non-toxic, foul, subterminal/free spores (→ Hot Malachite Green stain) Gram Positive Bacilli OBLIGATE ANAEROBE
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