Bacterial density information may help guide treatment options

Real-time quantitative polymerase chain reaction may be a good way to assess the nasopharyngeal interactions between various bacteria, according to study findings published online recently.

Keith P. Klugman

Keith P. Klugman, MD, PhD, who is the William H. Foege Chair of Global Health at the Rollins School of Public Health in Atlanta, and colleagues used real-time quantitative polymerase chain reaction (qPCR) and culture to detect and in the nasopharynx of 360 Peruvian children.

The researchers reported that higher bacterial densities, defined as more than 105 colony-forming units (CFU)/mL measured by qPCR, yielded better results than lower densities.

Also, Klugman and colleagues reported that densities of H. influenzae were positively correlated with S. pneumoniae densities, whereas S. pneumoniae and S. aureus were not.

“As colonization density may be an initial precursor to disease caused by these bacteria and may also be important for transmission, our study suggests that future colonization studies of these pathogens should also measure bacterial density,” the researchers concluded.

They added that knowing these densities and how these bacteria interact are key to developing vaccines and antimicrobials, “which target specific bacteria and may unexpectedly influence the bacterial flora.”

Keith P. Klugman, MD, PhD, can be reached at keith.klugman@emory.edu.

Disclosure: Klugman reports serving as a consultant for GlaxoSmithKline, Merck and Pfizer Vaccines.