In the case of a serious pertussis infection, what is the first line of treatment?

The first-line treatment for a serious pertussis infection is azithromycin. Azithromycin is a macrolide antibiotic that is effective against the bacteria Bordetella pertussis, which causes whooping cough. It works by inhibiting bacterial protein synthesis, leading to the arrest of bacterial growth.

Azithromycin has certain advantages over other macrolides, such as erythromycin and clarithromycin, including a more favorable dosing regimen and fewer gastrointestinal side effects, which can improve adherence. It also has a broader spectrum of activity and better tissue penetration, making it particularly effective in treating and preventing the transmission of pertussis.

In the context of pertussis, treatment is most effective when initiated early in the course of the illness, helping to reduce symptoms and preventing further spread. While erythromycin and clarithromycin are also effective treatments, azithromycin has become the preferred choice due to its convenience and tolerability. Dexamethasone is not an appropriate treatment for this bacterial infection; it is a corticosteroid used to reduce inflammation and has no antibacterial properties.