Nontypeable Haemophilus influenzae as a Pathogen in Children

Abstract

Nontypeable Haemophilus influenzae is a significant pathogen in children, causing otitis media, sinusitis, conjunctivitis, pneumonia, and occasionally invasive infections. H. influenzae type b conjugate vaccines have no effect on infections caused by nontypeable strains because nontypeable strains are nonencapsulated. Approximately, one-third of episodes of otitis media are caused by nontypeable H. influenzae and the bacterium is the most common cause of recurrent otitis media. Recent progress in elucidating molecular mechanisms of pathogenesis, understanding the role of biofilms in otitis media and an increasing understanding of immune responses have potential for development of novel strategies to improve prevention and treatment of otitis media caused by nontypeable H. influenzae. Feasibility of vaccination for prevention of otitis media due to nontypeable H. influenzae was recently demonstrated in a clinical trial with a vaccine that included the surface virulence factor, protein D.

A PCR–High-Resolution Melt Assay for Rapid Differentiation of Nontypeable Haemophilus influenzae and Haemophilus haemolyticus

“…ontypeable Haemophilus influenzae (NTHi) is an important cause of respiratory system-related infections, including otitis media (OM), exacerbations of chronic obstructive pulmonary disease, chronic bronchitis, and bronchiectasis (1)(2)(3). There are also reports of its increasing importance as a cause of invasive infections in regions with H. influenzae type b immunization (4)(5)(6).…”

Vaccine development forMoraxella catarrhalis: rationale, approaches and challenges

“…Based on cultures of middle ear fluid obtained by tympanocentesis, the 'gold standard' in determining etiology, M. catarrhalis causes 15-20% of acute otitis media cases [5]. Acute otitis media owing to M. catarrhalis is clinically milder than that caused by S. pneumoniae, with less fever and a lower likelihood of observing a red bulging tympanic membrane.…”

“…Streptococcus pneumoniae, nontypeable Haemophilus influenzae and Moraxella catarrhalis are the three most common bacterial causes of otitis media [5]; thus, the most successful vaccine approach will involve preventing infections by these three pathogens. M. catarrhalis has received less attention than the others as episodes of otitis media are less numerous than those caused by the pneumococcus and H. influenzae, and perhaps because M. catarrhalis causes milder acute disease [6].…”

Simultaneous Identification of Haemophilus Influenzae and Haemophilus Haemolyticus using Real-Time PCR

“…In children with cystic fibrosis, NTHi is an early colonizer that is associated with impaired mucociliary function, thereby increasing the risk of infection by other H. influenzae strains or pathogenic species [1,4]. NTHi also causes many other acute and chronic diseases, especially in children, including conjunctivitis, otitis media and sinusitis [5]. In contrast, the closely related species H. haemolyticus, which occupies the same niches as H. influenzae, is generally considered to be nonpathogenic [4].…”