Diagnostic Microbiology and Immunology Chapter 31 Diagnostic Microbiology and Immunology

Lab Diagnostic Time Lines

The Swab Clicker Question:

Here’s Some, Depending on Specimen Clicker Question

Urine Analysis Dip Sticks Top: After reaction with metabolites in urine. Bottom: Before reaction with metabolites in urine Test time = 60 sec. Measures: glucose, bilirubin, ketones, sp. gravity, pH, protein, urobilinogen, nitrite, esterases. Top two right are false positives to show the color reaction.

Eosin Methylene Blue Agar

There are hundreds of Selective and Differential Bacteriological Media Text goes on describing particular samples: wounds, feces, genital swabs, etc. We will cover those when we get to specific diseases.

Urethral Swab: Microscopy + Plating on Thayer-Martin Agar Oxidase Test Reagent poured onto the agar AFTER the colonies grew up.

Gas Pack, Anaerobic Chamber

Some Clinical Tests

Metabolic Reactions The Classic API-20e Glucose Phenol Red with Durham tube. TSI: triple sugar iron agar. Citrate Test

More Clinical Tests

Testing Antibiotic Sensitivity Kirby-Bauer Zone of Inhibition E-test. MIC: Minimal Inhibitory Concentration

Some Antibiotics – Interpretation of Size of the Zone of Inhibition

Pseudomonas aeruginosa MICs Each numbered row – one antibiotic, highest conc at left, lowest at right. Clicker Question:

E test Clicker Question:

Working in a BSL-4 Lab The Gen Micro Labs in AHC2 are BSL-1, most our research labs are BSL-2. BSL-3 labs: to contain pathogens that could be infective as an aerosol. BSL-1: lab people wear lab coats, gloves..and usually does not involve pathogens. BSL-2: needs to contain pathogens in hoods, etc. Aerosol generating equipment must be in a biosafety cabinet.

Disease Progression: Untreated Typhoid Fever Antibody Titers: Generally done by serial 1:2 dilutions from a blood sample. Highest dilution that brings about an Ab-Ag reaction. Clicker Question:

Disease Progression: Untreated Typhoid Fever Antibody Titers: Generally done by serial 1:2 dilutions from a blood sample. Highest dilution that brings about an Ab-Ag reaction. Clicker Question

Monoclonal Antibodies

Precipitin Reaction

Precipitin Rxns on a Glass Slide Clicker Question:

Agglutination Reactions

Latex Bead Agglutination for S. aureus

Fluorescent Antibodies Clostridium septicum stained with FITC-Ab, C. chauvoel stained with Rhodamine-Ab

Direct and Sandwich (Indirect)

Yellow-Green cells are CD8 Cells Red-orange cells are CD-4 Cells B and T Cells… Yellow-Green cells are CD8 Cells Red-orange cells are CD-4 Cells

Cell Sorting Clicker Question:

Enzyme Immuno-Assays

EIA Kits for Small Clinics

Immunoblots: Detecting Blotted Proteins (after electrophoresis)

Nucleic Acid Diagnostics

PCR Detecting Mycobacteium tuberculosis Lanes 1 + 10 Molecular Weight Standards Lanes 2-12 from different TB patients sputum Lanes 13-14 from non-TB patients with lung symptoms. Lane 15 – from known Mycobacterium tuberculosis DNA.