Nasopharyngeal microbiota evaluation in three cohorts of children in the Romanian pediatric population

Background

The nasopharyngeal microbiota represents one of the key factors related to infectious diseases in children [1]. The infectious agents and their resistance patterns are main factors driving disease severity. Nasopharyngeal carriage is high in children, especially for Staphylococcus aureus [2, 3].

Methods

We performed a screening study for nasopharyngeal carriage of Staphylococcus spp. in immunocompetent children aged 7-10 years old, attending a community school in central Bucharest (group 1), and in two groups of immunosuppressed children: children with hemato-oncologic diseases (lymphoma/leukemia) admitted to the Fundeni Clinical Institute, Bucharest (ages 2-10 years, group 2), and institutionalized children with vertically transmitted HIV infection, from the National Institute for Infectious Diseases “Prof. Dr. Matei Balş”, Bucharest (ages 1-10 years, group 3).

Results

We analyzed data from 139 pharyngeal swabs (35.3% in group 1, 56.1% group 2 and 8.6% group 3), and 143 nasal swabs (37.1% group 1, 54.5% group 2 and 8.4% group 3). Pharyngeal cultures were positive for Staphylococcus spp. in 28.6% of children in group 1, 11.5% in group 2 (p=0.00755 vs. group 1) and 16.7% in group 3 (p=0.20045 vs. group 1). Of the positive pharyngeal samples, 92.9% were S. aureus in group 1, 100% in group 2 and 100% in group 3.

Nasal cultures were positive for Staphylococcus spp. in 84.9% of children in group 1, 48.7% group 2 (p=0 vs. group 1) and 50.0% group 3 (p=0.00391 vs. group 1). Of the positive nasal samples, 62.2% were identified as S. aureus in group 1, 94.6% in group 2 (p=0.00027 vs. group 1) and 66.7% in group 3.

Conclusion

Pharyngeal carriage of Staphylococcus strains was low, however when positive, most strains were S. aureus. Nasopharyngeal carriage was significantly higher in immunocompetent children from the community compared to immunodepressed children. When present, S. aureus had a higher prevalence compared to coagulase-negative staphylococci (CoNS), particularly in immunodepressed children.