Haemophilus infections

Heamophilus influenzae is a G-, immobile, non-sporulating bacterium (sometimes it appears as a rod, sometimes as a coccus). According to the capsular antigen, we are able to distinguish 6 types (a-f), with the most virulent being type b. Unencapsulated types are responsible for exacerbations of chronic airway inflammation.

Epidemiology

Occurrence is mainly related to the winter months, it can also be isolated in healthy individuals. It is a typical human pathogen; in newborns, infections usually do not occur due to the presence of maternal Ig. However, when their levels drop, serious infections often occur. It is reported that in former times every child under the age of three had some sort of haemophilic infection, especially in the form of systemic disease (meningitis, epiglottitis, pneumonia, pericarditis, pyarthrosis), after the fifth year systemic infections were rare, more common are mounting on other infections - sinusitis , otitis. The situation has changed with the introduction of vaccination.

Patogenesis

Hemophilic penetration occurs with ciliotoxin or post-inflammatory respiratory epithelium. Unencapsulated strains cause local infection. Encapsulated strains resist phagocytosis and complement, penetrate the bloodstream and are invasive. Virulence factors in encapsulated strains include:

• capsule;
• outer membrane proteins;
• IgA cleaving protease;
• endotoxin.

Clinical picture

Epiglottitis

• it most often occurs in children aged two to three years, with a sudden onset;
• fever;
• sore throat and dysphagia;
• gradually increasing shortness of breath;
• epiglottis: cherry enlarged, swollen; phlegmonous or edematous picture.

Pneumonia

• fever, dry cough, purulent sputum
• common in children in developing countries

Meningitis

• children from three months to five years, the smaller, the less prominent
• primary meningitis (starting from full health) or secondary meningitis (preceded by upper respiratory tract infections)
• initial symptoms: fever, apathy, anorexia and vomiting
  • in infants we observe a domed fountain
  • older children develop meningeal syndrome
• complications: secondary pneumonia, arthritis, pericarditis.

Diagnostics

It is necessary to use transport soils for the cultivation of hemophilus, as it is characterised by great instability.

Prevention

In the Czech Republic, vaccination against Hemofil B with an adsorbed conjugated polysaccharide vaccine is part of the hexavaccine. Carrier is cured with rifampicin.

Therapy

• Minor infections:
  • For beta-lactamase-free strains: ampicillin, amoxicillin
  • For beta-lactamase-producing strains: protected aminopenicillins, cephalosporins 2. − 3. generation, macrolides

• Meningitis, epiglottitis
  • 3rd generation cephalosporins
  • corticosteroids for the treatment of edema
  • ICU care

Other infections

Haemophilus ducreyi – soft ucer, ulcus molle

Links

Similar articles

Haemophilus meningitis▪ Haemophilus influenzae

Source

• ws:Hemofilové infekce
• BENEŠ, Jiří. Studijní materiály [online]. [cit. 2010]. <http://jirben.wz.cz>.

Literature

• HAVLÍK, Jiří, et al. Infektologie. 2. vydání. Praha : Avicenum, 1990. 393 s. ISBN 80-201-0062-8.

• LOBOVSKÁ, Alena. Infekční nemoci. 1. vydání. Praha : Karolinum, 2001. 263 s. ISBN 80-246-0116-8.

• BENEŠ, Jiří, et al. Infekční lékařství. 1. vydání. 2009. ISBN 978-80-7262-644-1.