Bacteria from bronchoalveolar lavage fluid from children with suspected chronic lower respiratory tract infection: results from a multi-center, cross-sectional study in Spain

Abstract

This cross-sectional study assessed the prevalence of bacteria isolated from Spanish children with suspected chronic lower respiratory tract infection (LRTI) for whom bronchoalveolar lavage (BAL) was indicated. BAL fluid (BALF) was collected from 191 children (aged ≥ 6 months to < 6 years, with persistent or recurrent respiratory symptoms, non-responders to usual treatment) and cultured. Nasopharyngeal swabs (NPSs) were also obtained and cultured to assess concordance of BALF and NPS findings in the same patient. Streptococcus pneumoniae, Haemophilus influenzae, or Moraxella catarrhalis were identified from BALF with a bacterial load indicative of infection (> 10⁴ colony-forming units/mL) in 10.5, 8.9, and 6.3% of children, respectively. Clinical characteristics were similar among participants, regardless of positivity status for any of the bacteria. Approximately 26% of pneumococcal isolates were PCV13 serotypes, and 96% of H. influenzae isolates were non-typeable (NTHi). Concordance between BALF and NPS isolates was 51.0% for S. pneumoniae, 52.1% for H. influenzae, and 22.0% for M. catarrhalis.

Conclusion: S. pneumoniae, NTHi, and M. catarrhalis were the main bacteria detected in BALF and NPS. Children with suspected chronic LRTI may benefit from a vaccine protecting against NTHi. What is Known: • Chronic lower respiratory tract infection (LRTI) in children can cause high morbidity and is a major use of healthcare resources worldwide. Despite this, their etiology or potential preventive measures are poorly assessed. • Bronchoalveolar lavage can be used to determine bacterial etiology of chronic LRTI. What is New: • We used conventional and molecular techniques to show that Haemophilus influenzae, Streptococcus pneumoniae, and Moraxella catarrhalis were present in the LRT of Spanish children with suspected chronic LRTI • Concordance between isolates from bronchoalveolar lavage fluid and nasopharyngeal swabs was low, suggesting that samples from the upper respiratory tract could not reliably predict the bacterial etiology of suspected chronic LRTI.

Keywords: Bronchoalveolar lavage; Children; Chronic lower respiratory tract infection; Nasopharyngeal colonization; Non-typeable Haemophilus influenzae; Streptococcus pneumoniae.

Fig. 1

Serogroup and serotype distribution of S. pneumoniae-positive children for cultures meeting the cut-off for infection from BALF (a; N = 21) and cultures of any load from NPS (b; N = 105); BALF, bronchoalveolar lavage fluid; NPS, nasopharyngeal swab; N, number of unique isolates from children with positive quantitative identification for S. pneumoniae; PHiD-CV, pneumococcal polysaccharide non-typeable Haemophilus influenzae protein D-conjugate vaccine; PCV13, 13-valent pneumococcal conjugate vaccines