Haemophilus influenzae serotype e cross-infection from a cystic fibrosis patient in a paediatric hospital in Portugal
Abstract number: 903_r2321
Haemophilus influenzae (HI) has been responsible for a number of human diseases, including chronic respiratory infections as cystic fibrosis. Most of HI strains are noncapsulated, being the capsulated strains classified in six serotypes, af. The introduction of Hib vaccine in many countries contributed to a decline of this serotype. Many studies have been done to find out the possible changes that may occur in the epidemiology of the HI disease, namely changes related to capsule replacement and virulence of non-b strains.
Phenotype and molecular characterisation of three HI strains isolated in a Children's Hospital in OPorto, Portugal, involved in a cross-infection. Two of the strains were isolated, within 1 month from a boy, 11 years old, with cystic fibrosis. The other strain was collected from a nurse that was in contact with this patient, 4 days after the first isolate of the child.
Biotype, serotype (agglutination procedure and PCR), b-lactamase production (nitrocefin) and antibiotic susceptibility (microdilution assay) to 14 antibiotics (ampicillin, amoxicillin-clavulanate, cefotaxime, cefaclor, cefuroxime, cefepime, meropenem, tetracycline, chloramphenicol, trimethoprimsulphamethoxazole, rifampicin, ciprofloxacin, azithromycin and erythromycin) were performed to characterise the phenotype of isolates. Breakpoints used were according to NCCLS 2003. A molecular approach was used to evaluate the clonality of isolates (pulsed-field gel electrophoresis).
All three strains were b-lactamase negative, belonged to biotype IV and had the same capsular serotype, e. They had the same antibiotic susceptibility pattern, being only resistant to trimethoprimsulphamethoxazole DNA typing permitted the identification of the same pattern in the three strains showing that all had the same origin and were closely related.
These results are in agreement with a cross infection of HI serotype e from a cystic fibrosis child to the nurse that was in contact with him. One month later the child was still infected with the same strain. Serotype e strains are still rare in Portugal, although they are emerging after the introduction of the Hib vaccine. It is of most concern to continue monitoring serotypes of HI responsible for different infections, to detect possible changes that may occur after the introduction of the vaccine in our country."
|Session name:||XXIst ISTH Congress|
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