Objective: The study aimed to describe the microbiology of the middle ear and nasopharynx and to determine the prevalence of Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis in a group of children vaccinated with pneumococcal conjugate vaccine (PCV) who were submitted to insertion of ventilator tubes by recurrent acute otitis media.
Methods: We analyzed 278 middle ear effusions and 139 nasopharynx samples obtained from 139 children submitted to myringotomy and ventilation tube insertion by recurrent acute otitis media, from June 2017 to June 2021. The age of the children ranged from 6 months to 9 years and 10 months, with a median of 21 months. Patients had no signs of acute otitis media or respiratory tract infection and were not under antibiotic therapy at the time of the procedure. Middle ear effusion aspiration (OMS) was performed by tympanocentesis, using an Alden-Senturia collector and the nasopharynx (NF) sample was collected with swab. Bacteriological studies and multiplex PCR were performed for simultaneous detection of the three pathogens. The direct molecular determination of pneumococcal serotypes was effected by real-time PCR. Statistical analysis performed with chi-square test to verify associations between categorical variables and measures of association force based on prevalence ratios with 95% confidence interval. p≤0.05 values were considered statistically significant.
Results: Vaccination coverage was 77.7% with basic regimen plus booster dose and 22.3% with basic regimen. In OMS, by culture, H. influenzae was identified in 27 children (19.4%), S. pneumoniae in 7 (5.0%) and M. catarrhalis also in 7 (5.0%). PCR detection found H. influenzae in 95 (68.3%), S. pneumoniae in 52 children (37.4%) and M. catarrhalis in 25 (16.5%), an increase of three to seven times in comparison with culture. In NF, culture isolated H. influenzae in 28 children (20.1%), S. pneumoniae in 29 (20.9%) and M. catarrhalis in 12 (8.6%). PCR identified H. influenzae in 84 children (60.4%), S. pneumoniae in 58 (41.7%) and M. catarrhalis in 30 (21.5%), a two to three-fold increase in the detection rate. Pneumococcal serotype 19A was the most common, both in the ears and in the nasopharynx. In the ears, of the 52 children who had pneumococcus, 24 (46.2%) of them had serotype 19A. In the nasopharynx, of the 58 patients who presented pneumococcus, 37 (63.8%) had serotype 19A. Of the 139 children, 53 (38.1%) presented polymicrobial NF samples. Of these, 47 (88.7%) had some of the three otopathogens in the middle ear and 40 of them (75.5%) had H. influenzae in the ears, especially when in NF, this was in conjunction with S. pneumoniae.
Conclusion: The prevalence of bacteria in a group of Brazilian children immunized with pneumococcal conjugate vaccine and who required insertion of ventilation tubes due to recurrent acute otitis media is similar to that reported in other parts of the world after the advent of PCV. H. influenzae was the most common ly found germ, both in the nasopharynx and middle ear, and serotype 19A S. pneumoniae was the most detected pneumococcus in the nasopharynx and middle ear. Polymicrobial colonization of the nasopharynx was strongly associated with the detection of H. influenzae in the middle ear.
Keywords: Haemophilus influenzae; M. catarrhalis, Otitis media; Pneumococcal vaccination; Streptococcus pneumoniae.
