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Haemophilus infection in cystic fibrosis
R J Rayner1, E J Hiller, P Ispahani
1Department of Paediatrics, City Hospital, Nottingham.
Insights
Pediatric cystic fibrosis patients show higher rates of Haemophilus influenzae isolation compared to asthma patients. This bacterium is more prevalent during cystic fibrosis exacerbations, unlike in asthma.
Area of Science:
- Pediatric Pulmonology
- Microbiology
- Infectious Diseases
Background:
- Non-typeable Haemophilus influenzae (NTHi) is a common respiratory pathogen.
- NTHi colonization is frequently observed in children with cystic fibrosis (CF).
- The role of NTHi in asthma exacerbations is less understood.
Purpose of the Study:
- To compare the isolation rates of Haemophilus influenzae and Haemophilus parainfluenzae in pediatric patients with cystic fibrosis and asthma.
- To investigate the association between H. influenzae isolation and exacerbations in both patient groups.
- To analyze the distribution of H. influenzae and H. parainfluenzae biotypes.
Main Methods:
- A prospective, one-year follow-up study.
- Involved 27 pediatric cystic fibrosis patients and 27 matched asthma patients (under 12 years).
- Regular collection of cough swabs and sputum specimens every two months for bacterial isolation and biotyping.
Main Results:
- Significantly higher isolation rates of non-capsulated Haemophilus influenzae in cystic fibrosis patients compared to asthma patients.
- Haemophilus parainfluenzae isolation rates were similar between the two groups.
- H. influenzae isolation increased significantly during exacerbations in cystic fibrosis patients, but not in asthma patients.
- Biotype I of H. influenzae was associated with exacerbations in cystic fibrosis.
- Biotype V of H. influenzae was more common than previously reported but not linked to exacerbations.
Conclusions:
- Non-capsulated Haemophilus influenzae is more frequently isolated from pediatric cystic fibrosis patients than from those with asthma.
- H. influenzae plays a more significant role in exacerbations of cystic fibrosis than in asthma.
- Further research into the clinical significance of specific H. influenzae biotypes in CF is warranted.
Abstract:
Twenty seven patients with cystic fibrosis under the age of 12 years and 27 matched patients with asthma were followed up in a prospective study for one year. The isolation rate of non-capsulated strains of Haemophilus influenzae from cough swabs and sputum specimens taken at routine clinic visits every two months was significantly greater in cystic fibrosis than in asthma. Haemophilus para-influenzae was equally common in both groups. During exacerbations the isolation rate of H influenzae in cystic fibrosis was significantly greater than at other times, whereas in asthma there was no significant difference. The distribution of biotypes of H influenzae and H parainfluenzae was similar in the two groups. In cystic fibrosis, biotype I was associated with exacerbations. Biotype V was more common than in previous studies, but was not associated with exacerbations.