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Streptococcal impetigo and acute glomerulonephritis in children in Cairo
Insights
Impetigo contagiosa in children is linked to Streptococcus pyogenes strains, with specific types associated with post-impetigo nephritis. Houseflies may transmit these bacterial strains, highlighting a potential public health concern.
Area of Science:
- Microbiology
- Epidemiology
- Pediatrics
Background:
- Impetigo contagiosa is a common skin infection in children.
- Post-impetigo nephritis is a known complication.
Purpose of the Study:
- To investigate Streptococcus pyogenes strains causing impetigo in Cairo.
- To identify M-protein types associated with impetigo and nephritis.
- To explore potential transmission vectors like houseflies.
Main Methods:
- Bacterial typing of Streptococcus pyogenes strains from skin lesions.
- Serological confirmation of post-impetigo nephritis using serum C3 levels and urinalysis.
- Isolation of bacterial strains from houseflies for comparison.
Main Results:
- Streptococcus pyogenes was found in 84% of impetigo lesions.
- Specific T-protein types (e.g., T3/B3264, T13/B3264, T14/49) were prevalent.
- Nephritis was associated with T4 (M 60) and T14/49 (M 49) strains, with 70% and 40% of patients developing nephritis, respectively.
- Identical strains were recovered from skin lesions and houseflies.
- Antistreptolysin O (ASO) response was higher in nephritis cases.
Conclusions:
- Specific Streptococcus pyogenes strains are linked to impetigo contagiosa and post-impetigo nephritis.
- Houseflies may act as vectors for impetigo-causing bacteria.
- Monitoring M-protein types is crucial for understanding nephritis risk.
Abstract:
Impetigo contagiosa in Cairo affected young children of both sexes, the face being the main site. Post-impetigo nephritis, confirmed by a low serum C3 level and by urinalysis, occurred in only 11% of cases. Streptococcus pyogenes strains were recovered from 84% of the skin lesions. Sixteen types were identified according to their T-protein, and most infections were associated with T3/B3264, T13/B3264, T5, T11, T12, T8/25/Imp 19 and T14/49; the majority of these types were also recovered from houseflies. The types isolated from cases of post-impetigo nephritis were T4 (M 60), T14/49 (M49), T8/25/Imp 19 (mostly M 55) and T11. Seventy percent of the patients infected with T4 (M 60) and 40% of those infected with T14/49 (M 49) developed nephritis. Strains isolated from the skin bore a closer resemblance to those isolated from the nose than to those found in the throat. The ASO response was poor in uncomplicated impetigo but the titre rose more aften in post-impetigo nephritis.