lab diag id

8/3/2019 lab diag ID

1/22

LABORATORY DIAGNOSIS OF

INFECTIOUS DISEASES


2/22

Infectious diseases

Infectious diseases, also known as communicablediseases, contagious diseases or transmissiblediseases

Infectious diseases are diseases that followcolonization of the body by pathogens. Followingcolonization, the pathogens go on to causedisease within the body.

Communicable and contagious diseases areinfectious diseases that are transmitted fromperson to person.


3/22

Pathogens Commonly Transmitted by

Food and Water


4/22

Examples of Infectious Diseases Caused by Bacteria


5/22

Examples of Infectious Diseases Caused by Fungi


6/22

Examples of Infectious Diseases Caused by Protozoa


7/22

Clinical Specimens from Various

Anatomical Sites and Organ Systems

Circulatory System

Skin, Abscess, and Wound Specimens

Eyes and Ears

Respiratory System

Central Nervous System

Urinary Tract

Genital Tract

Oral Cavity Gastrointestinal Tract

Body Fluids


8/22

Diagrammatic representation of the steps involved in the

diagnoses of infectious diseases


9/22

Clinical Specimens Used for the

Diagnosis of Infectious Diseases


10/22


11/22

The Three Components of Specimen

Quality1. Proper selection of the specimen

The specimen must be the appropriate type to diagnose the infectious disease

suspected by the clinician.

2. Proper collection of the specimen

The specimen must be collected in a manner that eliminates or minimizes contamination

of the specimen with indigenous microflora. Sometimes special collection devices arerequired.

3. Proper transport of the specimen

The specimen must be transported to the laboratory in a manner that ensures that the

pathogen remains viable and/or preserves its morphology (e.g., rapid transport,

sometimes by packing the container in ice or by using a preservative)

The person who collects the specimen is ultimately responsible for its

quality.

Poor-quality specimens are rejected as part ofthe CMLs quality

assurance program. Workup of a poor-quality specimen could generate

results that are not clinically relevant and might endanger the life of

the patient.


12/22

General Clinical Microbiology

Laboratory Methods

Examining Clinical Specimens and Colonies

Using Wet Mounts

Culture Media

Types of Culture Media

Importance of Sterile Technique

Inoculation of Culture Media

Incubation of Inoculated Culture Media

Manual Blood Culture Methods


13/22


Laboratory Methods Staining Techniques

Used in the Bacteriology Simple staining procedures

Structural staining procedures

Differential staining procedures

Other Than the Bacteriology Mycology

Calcofluor white

India ink wet mount (a blackcalled nigrosin can be used in place of India ink)

Lactophenol cotton blue

Parasitology Calcofluor white

Giemsa, Wright, and Wright- Giemsa stains

Modified Kinyoun acid-fast stain

Trichrome stain

Iodine


14/22


Laboratory Methods

Identification of Microorganisms Using

Biochemical Tests

Detecting the Presence or Absence of Specific

Enzymes

Determining an Organisms Ability to Catabolize

Various Substrates

Identification of Microorganisms Using Gas-Liquid Chromatography


15/22


Laboratory Methods

Immunodiagnostic Procedures

Antigen Detection Procedures

Antibody Detection Procedures

Specific Types of Immunodiagnostic Procedures

Specificity and Sensitivity, False-Positive and

False-Negative Results

Molecular Diagnostic Procedures


16/22


Laboratory Methods

Automation in the Clinical Microbiology

Laboratory

Automated Blood Culture Techniques

Automated Biochemical- and Enzyme-Based

Methods for Microorganism Identification

Automated Immunodiagnostic Procedures

Automated Molecular Diagnostic Procedures


17/22


Laboratory MethodsExamples of Pathogens Detected by Automated Immunodiagnostic Systems

Viruses Adenovirus; cytomegalovirus; HIV; Epstein-Barr virus; hepatitis A, B, C, and D

viruses; herpes simplex virus; influenza viruses A and B; measles virus; mumpsvirus; parvovirus; rubella virus

Bacteria Bordetella pertussis, Borrelia burgdorferi, Brucella abortus, Chlamydia

trachomatis, Clostridium difficile, Escherichia coli O157:H7, Helicobacterpylori, Legionella pneumophila, Listeria monocytogenes, Mycoplasmapneumoniae, Salmonella spp., Treponema pallidum

Fungi Aspergillus spp., Candida albicans

Parasites Entamoeba histolytica, Giardia lamblia, Toxoplasma gondii, Trypanosoma cruzi


18/22

The three main steps in polymerase

chain reactions.


19/22

Flowchart illustrating the sequence of events that occur within

the bacteriology section of the clinical microbiol-ogy laboratory.


20/22


21/22

Laboratory Procedures Used in the

Diagnosis of Viral Infections

Cell Cultures

Immunodiagnostic Procedures

Cytology and Histology Electron Microscopy


22/22

Infectious substance label that must be affixed to the outside of

any package containing potentially hazardous infectious

materials

lab diag id

Documents