The bacterium that causes tuberculosis (TB) — a life-threatening respiratory condition spread from person to person through infected particles in the air — takes weeks-to-months to grow, making it one of nature’s slowest-growing infections. That means a patient with suspected but unconfirmed tuberculosis can remain undiagnosed, untreated, and infectious while a laboratory grows a culture with the slow-to-replicate bacterium. Time ticks while people remain sick and contagious before an effective antibiotic is prescribed.
So what’s the key to faster diagnosis?
Dr. Max Salfinger, a University of South Florida College of Public Health (COPH) professor specializing in global health, is the coauthor of the paper “How Can the Tuberculosis Laboratory Aid in the Patient-Centered Diagnosis and Management of Tuberculosis?” The paper was published in the journal Clinics in Chest Medicine in December 2019.
“Mycobacterium tuberculosis replicates in 20 hours versus the 20 minutes it takes for common bacteria such as Staphylococcus aureus or Escherichia coli,” said Dr. Salfinger. “In the laboratory, this means instead of incubating the culture for one to two days, it takes weeks or even months for a culture to grow colonies of bacteria visible to the naked eye. When laboratories adopt rapid molecular detection methods, such as nucleic acid amplification [a sensitive, rapid diagnostic test that can be performed directly on a respiratory sample and can detect small numbers of bacteria by looking for the DNA], reporting is faster, with reporting of positive results in just hours. When antibiotic-resistance testing is also rapid, patient treatment can be adjusted sooner if needed, which in turn leads to a more accurate treatment regimen.”Friday Letter Submission, Publish on February 28