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Haemophilus influenzae non-type b infections in children
Insights
Most invasive Haemophilus influenzae non-type b infections occur in children with underlying medical conditions. Prompt serotyping and evaluation are crucial for detecting these infections.
Area of Science:
- Pediatric Infectious Diseases
- Microbiology
- Immunology
Background:
- Haemophilus influenzae non-type b (non-Hib) strains are typically nonpathogenic.
- Invasive infections with non-Hib strains are uncommon, especially in children.
- Understanding risk factors for non-Hib invasive infections is important for clinical management.
Purpose of the Study:
- To describe the clinical characteristics and predisposing factors of invasive non-Hib infections in children.
- To determine the frequency and serotypes of non-Hib invasive infections in a pediatric hospital setting.
Main Methods:
- Retrospective surveillance of invasive Haemophilus influenzae infections over four years.
- Analysis of patient demographics, underlying medical conditions, and isolate serotypes.
- Identification of non-type b isolates from sterile body sites.
Main Results:
- Nine children experienced 11 episodes of invasive non-Hib infections (9% of all invasive H. influenzae infections).
- Most infected children had significant underlying conditions, including lymphoproliferative disorders, immunoglobulin deficiency, congenital heart disease, cerebrospinal fluid leaks, or prematurity.
- Serotypes included f, e, and nontypable strains; only one child lacked a predisposing condition.
Conclusions:
- Invasive non-Hib infections in children are strongly associated with underlying medical conditions.
- Serotyping all H. influenzae isolates from sterile sites is recommended.
- Children with non-Hib isolates require evaluation for predisposing illnesses.
Abstract:
During a four-year surveillance period in a tertiary care children's hospital, nine children experienced 11 episodes of Haemophilus influenzae non-type b invasive infections, representing 9% of all invasive H influenzae infections. Of these nine children, two had lymphoproliferative disorders; one had immunoglobulin subclass deficiency; one had severe congenital heart disease, with chronic heart failure; two had cerebrospinal fluid leaks; and two were premature neonates whose mothers had prolonged rupture of amniotic membranes. Only one child had no evidence of an underlying condition that might predispose him to infection with these ordinarily nonpathogenic organisms. Three of the isolates were serotype f, one was serotype e, and the remaining seven were nontypable, with types a through f antisera. Thus, the majority of children experiencing invasive H influenzae non-type b infections appear to have a predisposing medical condition. To aid in detecting these unusual infections, all H influenzae isolates from otherwise sterile body sites should be serotyped, and those children with non-type b isolates should be evaluated for a possible predisposing underlying illness.