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Published on: February 23, 2014
Pneumococcal Mastoiditis in Children Before and After the Introduction of Conjugate Pneumococcal Vaccines
Emmanouil I Koutouzis1, Athanasios Michos, Foteini I Koutouzi
1From the *First Department of Pediatrics, †Department of Otolaryngology Head and Neck Surgery, ‡Department of Clinical Microbiology, Aghia Sophia Children's Hospital, University of Athens, Athens, Greece; and §Department of Microbiology, Medical School, University of Athens, Athens, Greece.
Insights
Pneumococcal conjugate vaccines (PCVs) reduced vaccine-type Streptococcus pneumoniae causing acute mastoiditis in children. However, serotype 19A increased and remains a significant cause of antibiotic-resistant infections, even after PCV13 introduction.
Area of Science:
- Pediatric Infectious Diseases
- Microbiology
- Vaccinology
Background:
- Acute mastoiditis (AM) is a bacterial infection of the mastoid bone.
- Streptococcus pneumoniae is a common pathogen causing AM in children.
- The introduction of pneumococcal conjugate vaccines (PCVs) aimed to reduce pneumococcal disease burden.
Purpose of the Study:
- To evaluate changes in serotype distribution and antibiotic resistance of Streptococcus pneumoniae causing AM in children post-PCV introduction.
- To assess the impact of PCV7 and PCV13 on serotype prevalence and resistance patterns.
Main Methods:
- Retrospective review of medical records for children diagnosed with pneumococcal AM from 1999 to 2014.
- Serotyping of S. pneumoniae isolates using the quellung reaction.
- Antibiotic susceptibility testing and detection of macrolide resistance genes.
Main Results:
- S. pneumoniae was isolated in 26.6% of AM cases.
- A significant decline in PCV7 serotypes and a rise in non-PCV and PCV13-specific serotypes were observed post-vaccine introduction.
- Serotype 19A significantly increased after PCV7 and remained prevalent, contributing to high rates of penicillin and erythromycin resistance.
Conclusions:
- PCV7 introduction led to serotype replacement and a rise in serotype 19A AM.
- PCV13 did not significantly reduce the overall incidence of pneumococcal AM or serotype 19A.
- Serotype 19A is a major driver of antibiotic resistance in pediatric AM.
Objectives:
To determine whether serotype distribution and antibiotic resistance of Streptococcus pneumoniae acute mastoiditis (AM) in children have changed in the post pneumococcal conjugate vaccines (PCVs) era.
Methods:
Medical records of pneumococcal AM cases, in a tertiary pediatric hospital were reviewed from January 1999 to December 2014. S. pneumoniae isolates were serotyped using the quellung reaction and tested for antibiotic susceptibility by E-test and for macrolide resistance genes by polymerase chain reaction.
Results:
Among 334 children with AM, S. pneumoniae was isolated from 89 (26.6%) with median age 22 months (interquartile range: 12-30 months). S. pneumoniae was recovered from ear fluid (58%), mastoid specimens (35.2%) and blood (6.8%). Resistance to penicillin, erythromycin and clindamycin was 12.4%, 49.4% and 18%, respectively. Distribution of pneumococcal serotypes before (1999-2005), after the introduction of PCV7 (2006-2010) and after PCV13 (2011-2014) was found: for the PCV7 serotypes 81%, 25% and 0% (P < 0.0001), for PCV13 additional serotypes 16.3%, 70.8% and 63.6% (P < 0.0001) and for non-PCV serotypes 2.3%, 4.1% and 36.3% (P = 0.0002), respectively. Significant increase was detected for the serotype 19A after PCV7, and this trend was not changed after PCV13 (2.3%, 50% and 50%, respectively; P < 0.0001). A significant proportion of resistant isolates to penicillin (54.5%) and erythromycin (34.8%) was identified as 19A.
Conclusions:
After the introduction of PCV7, a significant increase of serotype 19A and replacement of PCVs serotypes was identified. After PCV13, the overall proportion of pneumococcal mastoiditis and the incidence of serotype 19A were not significantly declined. A significant proportion of resistant isolates to penicillin and erythromycin is attributed to serotype 19A.
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