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A problem with the recognition of penicillin-resistant pneumococci
Abstract:
A strain of Streptococcus pneumoniae requiring 0.25 mg/1 penicillin to inhibit its growth was isolated from the antrum of a child who had no history of either foreign contacts or previous treatment with penicillin. The penicillin resistance was recognised by chance because the disc used contained substantially less than its stated content of 1.5 unit. When discs containing 2 units were used there was little reduction in size of the zone of inhibition.
Insights
A penicillin-resistant Streptococcus pneumoniae strain was discovered in a child with no prior antibiotic exposure. This finding highlights the potential for spontaneous development of antibiotic resistance in common bacteria.
Area of Science:
- Microbiology
- Infectious Diseases
- Antimicrobial Resistance
Background:
- Streptococcus pneumoniae is a common bacterium causing various infections.
- Penicillin has been a primary treatment for pneumococcal infections.
- The emergence of antibiotic resistance is a significant global health concern.
Observation:
- A strain of Streptococcus pneumoniae was isolated from a child's antrum.
- The child had no history of foreign travel or previous penicillin treatment.
- Initial penicillin susceptibility testing was inadvertently performed with an under-strength disc.
Findings:
- The isolated Streptococcus pneumoniae strain demonstrated resistance to penicillin, requiring 0.25 mg/L for growth inhibition.
- Confirmation with a standard 2-unit penicillin disc showed minimal inhibition zone, confirming resistance.
- This resistance was identified incidentally due to a faulty testing disc.
Implications:
- This case suggests that penicillin resistance in Streptococcus pneumoniae can arise spontaneously, even without apparent selective pressure.
- Early detection of resistance is crucial for effective treatment strategies.
- Further research is needed to understand the mechanisms and prevalence of such resistance in pediatric populations.