Dataset Information

The association between bacteria colonizing the upper respiratory tract and lower respiratory tract infection in young children: a systematic review and meta-analysis.

ABSTRACT:

Background

Bacteria colonizing the upper respiratory tract (URT) of young children play a key role in the pathogenesis of lower respiratory tract infection (LRTI).

Objectives

To systematically review the literature on the association between bacteria colonizing the URT and LRTI among young children.

Data sources

MEDLINE, Academic Search Premier, Africa-Wide Information and CINAHL, Scopus and Web of Science.

Study eligibility criteria

Studies published between 1923 and 2020, investigating URT bacteria from LRTI cases and controls.

Participants

Children under 5 years with and without acute LRTI.

Methods

Three reviewers independently screened titles, abstracts and full texts. Meta-analysis was done using Mantel-Haenszel fixed- or random-effects models.

Results

Most eligible studies (41/50) tested nasopharyngeal specimens when investigating URT bacteria. Most studies were of cross-sectional design (44/50). Twenty-four studies were performed in children in lower- or lower-middle-income countries (LMICs). There was higher prevalence of Haemophilus influenzae (pooled OR 1.60; 95% CI 1.23-2.07) and Klebsiella spp. (pooled OR 2.04; 95% CI 1.17-3.55) from URT specimens of cases versus controls. We observed a positive association between the detection of Streptococcus pneumoniae from URT specimens and LRTI after excluding studies where there was more antibiotic treatment prior to sampling in cases vs. controls (pooled OR 1.41; 95% CI 1.04-1.90). High density colonization with S. pneumoniae (>6.9 log¹⁰ copies/mL) was associated with an increased risk for LRTI. The associations between both Streptococcus and Haemophilus URT detection and LRTI were supported, at genus level, by 16S rRNA sequencing. Evidence for the role of Moraxella catarrhalis and Staphylococcus aureus was inconclusive.

Conclusions

Detection of H. influenzae or Klebsiella spp. in the URT was associated with LRTI, while evidence for association with S. pneumoniae was less conclusive. Longitudinal studies assessing URT microbial communities, together with environmental and host factors are needed to better understand pathogenesis of childhood LRTI.

SUBMITTER: Claassen-Weitz S

PROVIDER: S-EPMC8437050 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:High rates of potentially pathogenic bacteria and respiratory viruses can be detected in the upper respiratory tract of healthy children. Investigating presence of and associations between these pathogens in healthy individuals is still a rather unexplored field of research, but may have implications for interpreting findings during disease.We selected 986 nasopharyngeal samples from 433 6- to 24-month-old healthy children that had participated in a randomized controlled trial. We determined the presence of 20 common respiratory viruses using real-time PCR. Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus were identified by conventional culture methods. Information on risk factors was obtained by questionnaires. We performed multivariate logistic regression analyses followed by partial correlation analysis to identify the overall pattern of associations. S. pneumoniae colonization was positively associated with the presence of H. influenzae (adjusted odds ratio 1.60, 95% confidence interval 1.18-2.16), M. catarrhalis (1.78, 1.29-2.47), human rhinoviruses (1.63, 1.19-2.22) and enteroviruses (1.97, 1.26-3.10), and negatively associated with S. aureus presence (0.59, 0.35-0.98). H. influenzae was positively associated with human rhinoviruses (1.63, 1.22-2.18) and respiratory syncytial viruses (2.78, 1.06-7.28). M. catarrhalis colonization was positively associated with coronaviruses (1.99, 1.01-3.93) and adenoviruses (3.69, 1.29-10.56), and negatively with S. aureus carriage (0.42, 0.25-0.69). We observed a strong positive association between S. aureus and influenza viruses (4.87, 1.59-14.89). In addition, human rhinoviruses and enteroviruses were positively correlated (2.40, 1.66-3.47), as were enteroviruses and human bocavirus, WU polyomavirus, parainfluenza viruses, and human parechovirus. A negative association was observed between human rhinoviruses and coronaviruses.Our data revealed high viral and bacterial prevalence rates and distinct bacterial-bacterial, viral-bacterial and viral-viral associations in healthy children, hinting towards the complexity and potential dynamics of microbial communities in the upper respiratory tract. This warrants careful consideration when associating microbial presence with specific respiratory diseases.

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