September/2006
DISCUSSION:
Bordetella pertussis, a highly communicable gram-negative coccobacillus, causes pertussis (whooping cough). B. pertussis is an exclusively human pathogen that is transmitted via airborne droplets. The American Academy of Pediatrics (AAP) recommends a 14-day erythromycin regimen to treat pertussis, although a seven-day regimen may be as effective. However, it should be noted that erythromycin can cause gastrointestinal side effects (e.g., nausea, emesis, diarrhea) and increases the risk of pyloric stenosis in infants younger than two months.
Newer generation macrolides (e.g., azithromycin [Zithromax] and clarithromycin [Biaxin]) have similar bacterial eradication rates as erythromycin with less risk of side effects. The CDC recommends erythromycin, azithromycin, or clarithromycin as preferred agents, although it only recommends azithromycin for neonates because limited data suggest it may be the safest choice in this group. Trimethoprim/sulfamethoxazole (Bactrim, Septra) has been shown to reduce pertussis transmission and is an alternative treatment for patients who are allergic to macrolides. Other antibiotics, such as ampicillin, have not been shown to reduce pertussis transmission or symptoms.