Molecular Methods in Clinical Microbiology: A Historical Review
Continuing Education Credits
Objectives
- Describe some of the history of molecular methods and their introduction into the routine diagnostic laboratory.
- State advantages of molecular methods over traditional microbiology.
- Discuss the requirements and some of the challenges of implementing molecular methods in the setting of a routine clinical microbiology laboratory.
- Describe the principles of the basic methods of molecular techniques.
- Identify several assays of interest (and principles of reaction) for use in the field of infectious disease.
Course Outline
- Some History of Development
- Prior to 1985
- Chlamydia trachomatis and Neisseria gonorrhoeae
- Human Papilloma Virus and Mycobacterium
- Hepatitis and Viral Load Testing
- Initially, why were molecular methods challenging to perform in routine clinical laboratories?
- Why were Chlamydia and Neisseria logical targets for the development of a commercial molecular assay?
- Potential Benefits of Molecular Methods over Traditional Microbiology
- The Key Benefits: Improved Sensitivity of Detection
- The Key Benefits: Improved Sensitivity of Detection, continued
- The Key Benefits: Specificity of Identification
- The Key Benefits: Reduced Turnaround Time
- In traditional culture or antigen detection methods, detection sensitivity is adversely affected by which of the following?
- Why can molecular methods offer improved turnaround times over cultivation methods?
- Challenges for Implementing Molecular Microbiology
- Challenges for Implementation: Space Requirements
- Challenges for Implementation: Separation of Key Activities
- Challenges for Implementation: Workflow Requirements
- Challenges for Implementation: Required Work Skills
- Challenges for Implementation: Cost
- Why is it important to consider work space and workflow design for molecular methods?
- Molecular testing entails precise workflow requirements. Trained personnel must progress through a series of steps to ensure quality results. The following steps represent an ideal workflow.
- Definitions and Principles of Basic Methods
- Overview of Molecular Methods
- Categories of Methods
- Polymerase Chain Reaction
- Reverse Transcriptase Polymerase Chain Reaction
- Detection and Identification of Polymerase Chain Reaction Products
- Detection and Identification of Polymerase Chain Reaction Products: Advantages of Real-Time PCR
- What are the two general categories of nucleic acid amplification test (NAAT) techniques?
- Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps?
- Which statement about melt curve analysis is false?
- Application to Infectious Diseases
- Assays of Interest
- Assays of Interest for Infectious Disease [Staphylococcus aureus and Methicillin-resistant S. aureus (MRSA)]
- Identification of Staphylococcus aureus with Peptide Nucleic Acid (PNA)-Fluorescence In Situ Hybridization (FISH)
- Detection and Identification of Methicillin-resistant Staphylococcus aureus (MRSA) by Polymerase Chain Reaction (PCR)
- Development of Assays
- Molecular versus Culture: Pros and Cons
- Current and Future Prospects
- Potential disadvantages of molecular methods for methicillin-resistant Staphylococcus aureus (MRSA) include:
- Which of the following is a false statement about peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) methods for Staphylococcus?
- Assays of Interest for Infectious Disease [Influenza and Other Respiratory Viruses]
- Influenza: Prior Traditional Methods and the Need for Change
- Introduction of Molecular Methods
- 2009 H1N1 Influenza (Swine Flu)
- Incremental Improvements for Influenza Testing
- 2019 SARS-CoV-2 (COVID-19)
- Which statement about the 2009 H1N1 virus is true?
- Which statement is true about the molecular methods made available under the Emergency Use Authorization (EUA) during 2009 H1N1?
- Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assays are now available on which of the following types of PCR platforms?
- Assays of Interest for Infectious Disease [Clostridioides difficile]
- Clinical Significance of Clostridioides difficile
- Previous Methodologies: Culture and Cell Cytotoxicity Neutralization Assay
- Other Methodologies: Antigenic Detection of Toxin and Glutamate Dehydrogenase
- Molecular Methods
- Example #1
- Example #2
- Other Examples
- Several methods of detection are available for detecting Clostridioides difficile (previously known as Clostridium difficile) in clinical samples. Which method usually takes more than 48 hours to obtain results?
- What statement about the glutamate dehydrogenase (GDH) assay for Clostridioides difficile is true?
- Which of the following statements about the cell cytotoxicity neutralization assay (CCNA) for Clostridioides difficile (formerly known as Clostridium difficile) is true?
- The Future of Development
- Future of Development
- References
- References
Additional Information
Level of Instruction: Intermediate
Intended Audience: Medical laboratory scientists, medical
laboratory technicians, and personnel working in the microbiology and molecular sections of the laboratory. This
course is also appropriate for MLS and MLT students and pathology residents.
Author Information: Catherine Dragoni, MT(ASCP)SM, received her BS degree in medical technology from the State University of New York, Upstate Medical Center, Syracuse. She began her career as a bench microbiologist at Maine Medical Center, Portland, Maine. She has experience as the Assistant Chief Technologist of Microbiology and Molecular Pathology at NorDx Laboratories, Scarborough, Maine.
Reviewer Information:
Laurie Bjerklie, MA, MLS(ASCP)CM, is
an Education Developer for MediaLab and LabCE. She earned a B.S. in Medical
Laboratory Science from the University of North Dakota and an M.A. in
Curriculum and Instruction from Saint Xavier University. She has over 15 years
of experience in higher education and has held program director and faculty
positions in both MLT and MLS programs.
Dr. Julie Ann West is certified by the American Society for Clinical Pathology (ASCP) as a Medical Laboratory Scientist (MLS) and as a Specialist in Microbiology (SM). In addition, Dr. West has earned a PhD in Public Health - Infectious Disease Epidemiology - and is Certified in Public Health (CPH) by the National Board of Public Health Examiners. Dr. West is experienced as a Technical Specialist, Safety Officer, Educator, and Lead in the Veterans Administration Healthcare System and has prior experience as an Administrative Laboratory Director.
Course Description: This course offers a historical look at the progression of molecular methods in the clinical laboratory. It discusses the advantages of these molecular methods over traditional microbiology and the requirements and challenges faced during implementation in a routine clinical setting. Basic methods and molecular techniques are described, including the principle reactions of some assays of current interest for infectious diseases.