Should a patient with elevated Pertussis (whooping cough) Immunoglobulin G (IgG) and Immunoglobulin A (IgA) antibodies and symptoms be treated with antibiotics?

From the Guidelines

Yes, if a patient has elevated pertussis IgG and IgA antibodies along with symptoms consistent with pertussis (whooping cough), antibiotic treatment is recommended. The preferred antibiotic is azithromycin, typically given as 500 mg on day 1, followed by 250 mg daily for 4 more days (total 5-day course) 1. Alternative antibiotics include clarithromycin (500 mg twice daily for 7 days) or trimethoprim-sulfamethoxazole (one double-strength tablet twice daily for 14 days) for those who cannot take macrolides.

Key Considerations

• Treatment is most effective when started within the first 1-2 weeks of symptom onset, during the catarrhal phase, though antibiotics should still be given later to reduce transmission even if they may not alter the clinical course significantly 1.
• Antibiotics work by eliminating Bordetella pertussis bacteria from the respiratory tract, reducing infectiousness and limiting transmission to others.
• While serological evidence (elevated antibodies) with compatible symptoms strongly suggests pertussis infection, PCR or culture from nasopharyngeal specimens provides more definitive diagnosis when available.
• Close contacts should also receive antibiotic prophylaxis regardless of vaccination status 1.

Choosing the Right Antibiotic

• The choice of antimicrobial for treatment or prophylaxis should take into account effectiveness, safety, tolerability, ease of adherence to the regimen prescribed, and cost 1.
• Azithromycin and clarithromycin are as effective as erythromycin for treatment of pertussis in persons aged >6 months, are better tolerated, and are associated with fewer and milder side effects than erythromycin 1.

Reducing Transmission

• Antibiotic treatment of pertussis and judicious use of antimicrobial agents for postexposure prophylaxis will eradicate B. pertussis from the nasopharynx of infected persons (symptomatic or asymptomatic) 1.
• Approximately 80%--90% of patients with untreated pertussis will spontaneously clear B. pertussis from the nasopharynx within 3--4 weeks from onset of cough, however, untreated and unvaccinated infants can remain culture-positive for >6 weeks 1.

From the FDA Drug Label

Erythromycin tablets are indicated in the treatment of infections caused by susceptible strains of the designated microorganisms in the diseases listed below: ... Pertussis (whooping cough) caused by Bordetella pertussis. Erythromycin is effective in eliminating the organism from the nasopharynx of infected individuals, rendering them noninfectious

Treatment with antibiotics is recommended for a patient with elevated Pertussis (whooping cough) Immunoglobulin G (IgG) and Immunoglobulin A (IgA) antibodies and symptoms, as erythromycin is indicated for the treatment of pertussis caused by Bordetella pertussis 2.

• The patient's symptoms and elevated antibody levels suggest an active infection, making antibiotic treatment necessary to eliminate the organism and prevent further transmission.

From the Research

Treatment of Pertussis with Antibiotics

• Antibiotics are commonly used for treating confirmed cases of pertussis and also for disease prevention in outbreak situations, with little evidence of antibiotic resistance of Bordetella pertussis 3.
• The most commonly used antibiotics for pertussis treatment are erythromycin, clarithromycin, and azithromycin, with azithromycin being the preferred antibiotic for treatment or prophylaxis 4.
• A patient with elevated Pertussis Immunoglobulin G (IgG) and Immunoglobulin A (IgA) antibodies and symptoms may be treated with antibiotics to prevent transmission of pertussis to others, although antibiotics do not shorten the disease course or improve symptoms 4.

Effectiveness of Antibiotics in Treating Pertussis

• Short-term antibiotics (azithromycin for three days, clarithromycin for seven days, or erythromycin estolate for seven days) are equally effective with long-term antibiotic treatment (erythromycin estolate or erythromycin for 14 days) in the microbiological eradication of Bordetella pertussis from the nasopharynx 5.
• Effective regimens include: three days of azithromycin, seven days of clarithromycin, seven or 14 days of erythromycin estolate, and 14 days of erythromycin ethylsuccinate 5.
• Considering microbiological clearance and side effects, three days of azithromycin or seven days of clarithromycin are the best regimens 5.

Side Effects and Compliance

• Clarithromycin was better tolerated than conventional erythromycin therapy, with significantly fewer adverse events and higher compliance with the medication regimen 6.
• Short-term treatment with azithromycin or clarithromycin has fewer side effects compared to long-term treatment with erythromycin 7, 5.