Molecular Testing

Infections caused by bacteria have a major impact on public health, and the rapid spread of multidrug-resistant bacteria poses a serious threat to public health worldwide.  Traditional microbial culture methods can take several days, making diagnoses difficult and often leads to an overuse of broad-spectrum antibiotics to combat the illness.  Molecular testing for bacterial infections can help clinicians rapidly identify serious bacterial infections in patients.  This method of testing can also detect antibiotic-resistant genes, which leads to quicker, more targeted treatment.

When a person visits a physician office, urgent care, or emergency department with an infection, the physician may order a bacteria culture to identify organisms causing the illness.  A sample of tissue, blood, or other body fluids may be collected at the site of the suspected infection and sent to the laboratory for testing.  With microbial culture testing, enough bacteria must grow to test the sample for infection.  Results can take several days or weeks, as some types of bacteria grow slowly.  Once there are enough bacteria, the sample is examined using biochemical and other techniques to identify the causative pathogen.

Molecular diagnostic testing is much quicker and produces more sensitive results than microbial culturing.  A molecular test analyzes a patient’s sample for deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) coming from microorganisms.  DNA is located in the nucleus of every human and bacterial cell and is comprised of long strands of molecules that contain all of a person’s genetic information.  RNA is a single strand of genetic material found outside the nucleus that tells the functional structures in the cell what to do.

A polymerase chain reaction (PCR) is a specific type of molecular testing technique that amplifies and detects specific DNA and RNA sequences from a wide range of pathogens.  Molecular probes are used to identify and measure amplified DNA and RNA.  The probes are designed to target specific gene sequences that are unique to each pathogen, ensuring greater accuracy in identifying specific microorganisms.  Results are available within a few hours, making them useful in emergencies and for rapidly diagnosing contagious diseases.

Licking Memorial Hospital Laboratory uses molecular testing instruments to quickly identify infectious diseases.  The Cepheid GeneXpert is a closed-system PCR instrument that allows for testing a specific infectious disease, such as COVID-19 or Group B Streptococcus.  The BioFire FilmArray is a multiplex PCR system that can detect and identify several infections in a single sample simultaneously.  Such panels include:

• Respiratory Panel – can identify numerous viruses and bacteria that cause respiratory illness, including influenza, COVID-19, and RSV.
• Gastrointestinal Panel – can identify a wide range of viruses, bacteria, and parasites responsible for gastrointestinal problems.
• Meningitis/Encephalitis Panel – identifies pathogens that cause infections of the central nervous system.
• Blood culture panels – identifies infections in the blood stream, such as sepsis.

Molecular testing offers faster, more accurate diagnoses, which aids in timely treatment decisions, especially in an emergency setting.  This leads to improved patient outcomes, shorter hospital stays, and lower healthcare costs due to targeted therapies and reduced complications.  Molecular testing is also beneficial in rapidly identifying antibiotic resistance profiles for specific pathogens, which helps to promote antibiotic stewardship and reduce the rise of antibiotic-resistant bacteria.
 

| Posted On : 12/5/2024 3:33:51 PM