This study was carried out with the aim to investigate the presence of carriers of diphtheria bacillus in a sample of 1970 healthy children, 6-14 years aged, residing in eight Italian towns. Three non-toxigenic strains of Corynebacterium diphtheriae biotype mitis were isolated from as many healthy children. Molecular characterization by ribotyping showed close genetic relation of two of the wild strains with the C7(b) reference strain whereas one of the wild strains showed close genetic relation with two collection strains isolated in the same geographic area (Emilia-Romagna) from diphtheria patients in the seventy years. This supports the hypothesis of the persistence of some non toxigenic C. diphtheriae strains derived from ancient endemic strains under the selective pressure of mass immunization against diphtheria. The persistence of carriers of diphtheria bacilli, although non toxigenic, suggests that high levels of immunity must be maintained, not only in children, but also in adults by booster vaccination.

Persistence of circulation of Corynebacterium diphtheriae non-toxigenic strains and low prevalence of carriers in a sample of children vaccinated against diphtheria.

COCCHIONI, Mario;
2003

Abstract

This study was carried out with the aim to investigate the presence of carriers of diphtheria bacillus in a sample of 1970 healthy children, 6-14 years aged, residing in eight Italian towns. Three non-toxigenic strains of Corynebacterium diphtheriae biotype mitis were isolated from as many healthy children. Molecular characterization by ribotyping showed close genetic relation of two of the wild strains with the C7(b) reference strain whereas one of the wild strains showed close genetic relation with two collection strains isolated in the same geographic area (Emilia-Romagna) from diphtheria patients in the seventy years. This supports the hypothesis of the persistence of some non toxigenic C. diphtheriae strains derived from ancient endemic strains under the selective pressure of mass immunization against diphtheria. The persistence of carriers of diphtheria bacilli, although non toxigenic, suggests that high levels of immunity must be maintained, not only in children, but also in adults by booster vaccination.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11581/107157
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact