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Failure of penicillin to eradicate group A streptococci during an outbreak of pharyngitis
Abstract:
In an outbreak of group A streptococcal pharyngitis in a semi-closed community, 42 (25%) of 169 courses of antibiotic therapy failed to eradicate the organism. 16 (19%) of 85 individuals treated with intramuscular benzathine penicillin G and 9 (19%) of 47 patients treated with an oral antibiotic (penicillin V or erythromycin) continued to harbour the same serotype of group A streptococcus. 12 (48%) of 25 persons remained treatment failures after re-treatment; even after a third course of treatment 5 of 12 (42%) still harboured the organism. Neither antibiotic resistance of the epidemic strain nor reacquisition of the organism from contacts could be implicated as causes. The data suggest that many who did not respond to treatment were streptococcal carriers and raise the possibility that it is more difficult to eradicate the organism from the carrier than from the acutely infected individual.
Insights
Antibiotic treatment for group A streptococcal pharyngitis frequently failed, with many individuals remaining carriers. Eradicating the bacteria may be more challenging in carriers than in acutely infected patients.
Area of Science:
- Infectious Diseases
- Microbiology
- Public Health
Background:
- Group A Streptococcus (GAS) pharyngitis is a common bacterial infection.
- Antibiotic therapy is the standard treatment to prevent complications and transmission.
- Treatment failures in GAS pharyngitis outbreaks warrant further investigation.
Purpose of the Study:
- To investigate the failure rates of antibiotic therapy in eradicating GAS during an outbreak.
- To explore potential reasons for persistent GAS carriage after treatment.
Main Methods:
- Retrospective analysis of antibiotic treatment courses during a GAS outbreak in a semi-closed community.
- Tracking of treatment outcomes, including persistent GAS carriage.
- Assessment of antibiotic resistance and reacquisition from contacts.
Main Results:
- A significant proportion (25%) of antibiotic courses failed to eradicate GAS.
- Intramuscular benzathine penicillin G and oral antibiotics (penicillin V, erythromycin) showed similar failure rates (19%).
- Recurrence of carriage was high even after multiple treatment courses, suggesting challenges in eradication.
Conclusions:
- Standard antibiotic regimens demonstrate limited efficacy in eradicating GAS in certain individuals.
- Persistent GAS carriage post-treatment is a significant issue, potentially more difficult to resolve than acute infection.
- Findings suggest a need to reconsider treatment strategies for GAS, particularly in carrier states.