A single intramuscular dose of ceftriaxone changes nasopharyngeal bacterial flora in children with acute otitis media

Exploring the pediatric nasopharyngeal bacterial microbiota with culture-based MALDI-TOF mass spectrometry and targeted metagenomic sequencing

The nasopharynx is an important reservoir of disease-associated and antimicrobial-resistant bacterial species. This proof-of-concept study assessed the utility of a combined culture, matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS), and targeted metagenomic sequencing workflow for the study of the pediatric nasopharyngeal bacterial microbiota. Nasopharyngeal swabs and clinical metadata were collected from Cambodian children during a hospital outpatient visit and then biweekly for 12 weeks. Swabs were cultured on chocolate and blood-gentamicin agar, and all colony morphotypes were identified by MALDI-TOF MS. Metagenomic sequencing was done on a scrape of all colonies from a chocolate agar culture and processed using the mSWEEP pipeline. One hundred one children were enrolled, yielding 620 swabs. MALDI-TOF MS identified 106 bacterial species/40 genera: 20 species accounted for 88.5% (2,190/2,474) of isolates. Colonization by Moraxella catarrhalis (92.1% of children on ≥1 swab), Haemophilus influenzae (87.1%), and Streptococcus pneumoniae (83.2%) was particularly common. In S. pneumoniae-colonized children, a median of two serotypes [inter-quartile range (IQR) 1-2, range 1-4] was detected. For the 21 bacterial species included in the mSWEEP database and identifiable by MALDI-TOF, detection by culture + MALDI-TOF MS and culture + mSWEEP was highly concordant with a median species-level agreement of 96.9% (IQR 86.8%-98.8%). mSWEEP revealed highly dynamic lineage-level colonization patterns for S. pneumoniae which were quite different to those for S. aureus. A combined culture, MALDI-TOF MS, targeted metagenomic sequencing approach for the exploration of the young child nasopharyngeal microbiome was technically feasible, and each component yielded complementary data.

IMPORTANCE

The human upper respiratory tract is an important source of disease-causing and antibiotic-resistant bacteria. However, understanding the interactions and stability of these bacterial populations is technically challenging. We used a combination of approaches to determine colonization patterns over a 3-month period in 101 Cambodian children. The combined approach was feasible to implement, and each component gave complementary data to enable a better understanding of the complex patterns of bacterial colonization.

Recurrence up to 3.5 years after antibiotic treatment of acute otitis media in very young Dutch children: survey of trial participants

OBJECTIVE

To determine the long term effects of antibiotic treatment for acute otitis media in young children.

DESIGN

Prospective three year follow-up study within the framework of a primary care based, double blind, randomised, placebo controlled trial.

SETTING

53 general practices in the Netherlands.

PARTICIPANTS

168 children aged 6 months to 2 years with acute otitis media.

INTERVENTIONS

Amoxicillin 40 mg/kg/day in three doses compared with placebo.

MAIN OUTCOME MEASURES

Recurrence of acute otitis media; referral to secondary care; ear, nose, and throat surgery.

RESULTS

Acute otitis media recurred in 63% (47/75) of children in the amoxicillin group and in 43% (37/86) of the placebo group (risk difference 20%, 95% confidence interval 5% to 35%); 30% (24/78 amoxicillin; 27/89 placebo) of children in both groups were referred to secondary care, and 21% (16/78) of the amoxicillin group compared with 30% (27/90) of the placebo group had ear, nose, and throat surgery (risk difference -9%, -23% to 4%).

CONCLUSION

Recurrent acute otitis media occurred more often in the children originally treated with amoxicillin. This is another argument for judicious use of antibiotics in children with acute otitis media. Trial registration Netherlands Trial Register NTR1426.