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Random amplified polymorphic DNA analysis applied to acute otitis media caused by penicillin non-susceptible
T Nakashima1, K Fukushima, M Tahara
1Department of Otolaryngology, Okayama University Medical School, 2-5-1 Shikata-cho, Okayama 700-8558, Japan.
Insights
Penicillin non-susceptible Streptococcus pneumoniae (PNSSP) can cause acute otitis media (AOM). This study found no direct spread among children, suggesting surveillance during carrier states is crucial for managing PNSSP.
Area of Science:
- Microbiology
- Infectious Diseases
- Pediatrics
Background:
- Penicillin non-susceptible Streptococcus pneumoniae (PNSSP) is an increasing concern for treating acute otitis media (AOM).
- Daycare attendance is a known risk factor for AOM and PNSSP spread.
- The transmission dynamics of PNSSP during acute AOM infections remain under-evaluated.
Purpose of the Study:
- To investigate the clonality of PNSSP isolates from children with simultaneous AOM in a daycare setting.
- To determine if direct dissemination of PNSSP occurred among these pediatric patients.
Main Methods:
- Collected samples from seven children with AOM caused by PNSSP and six control samples.
- Utilized serotyping, antimicrobial resistance profiling, and sequencer-based random amplified polymorphic DNA (RAPD) genotyping.
- Validated RAPD genotyping results using bootstrap analysis for reproducibility.
Main Results:
- No evidence of direct PNSSP dissemination was found among the seven children, despite simultaneous AOM diagnoses.
- Genotyping results were highly reproducible, confirmed by high bootstrap scores.
- The study highlights the potential role of a common ancestral strain and the importance of carrier state surveillance.
Conclusions:
- Simultaneous PNSSP AOM in a daycare does not necessarily indicate a clonal outbreak.
- Surveillance for PNSSP during the carrier state is important for understanding transmission and preventing AOM.
- Automated sequencers and optimized kits enhance the reproducibility of RAPD genotyping.
Abstract:
The spread of penicillin non-susceptible Streptococcus pneumoniae (PNSSP) is an emerging problem for the treatment of acute otitis media (AOM). Attendance of children at day care centers, as well as the spread of PNSSP, is a risk factor for AOM. The status of the spread of PNSSP during the acute infection phase of AOM has not been evaluated. We examined the clonality of samples from seven children in a day care center who simultaneously developed AOM caused by PNSSP. The seven isolates from the children, and six control samples were grouped by serotyping, by determining resistance to antimicrobial agents, and by genotyping, carried out by sequencer-based random amplified polymorphic DNA (RAPD), and validated by bootstrap analysis. There was no evidence to indicate the direct dissemination of PNSSP among these patients in the day care center, although the simultaneous occurrence of PNSSP AOM had initially suggested a clonal outbreak. The possible presence of a common ancestral strain suggested the importance of surveillance during the carrier state. The result of RAPD genotyping was highly reproducible, as validated by the high bootstrap score. The use of an automated sequencer, in combination with a careful choice of primers, and commercially established kits, played a significant role in the reproducibility of the studies.