A total of 105 multiple-antibiotic-resistant invasive pneumococcal isolates recovered in Italy from 2001 to2003 were genetically characterized. Of these, 40 were penicillin-nonsusceptible (PNSSP) and 65 were penicillin-susceptible (PSSP) Streptococcus pneumoniae strains. Among the PNSSP isolates, 8 and 11 differentrestriction profiles were obtained for the pbp2b and pbp2x genes, respectively. Clonal groups were establishedon the basis of analysis of both pulsed-field gel electrophoresis (PFGE) types and multilocus sequence typing(MLST). Several international clones, such as Spain23F-1/ST81, Spain6B-2/ST90, Spain9V-3/ST156, andSweden15A-25/ST263, were identified among the PNSSP isolates. Other, smaller clones, such as the minorSpanish 19F clone/ST88 and Denmark14-32/ST230, were also found. Among the PSSP isolates, clones relatedto England14-9/ST9, Greece6B-22/ST273, and Portugal19F-21/ST177 were found. In addition, two large clonescomprised nonvaccine serotypes. One, comprising serotype 3 isolates, corresponded to the clone Netherlands3-31/ST180; the other, comprising serotype 15B/C isolates, ST474, was not related to any previously describedclone. Two small clusters related to the newly described clones Greece21-30/ST193 and Netherlands15B-37/ST199 included isolates with unrelated PFGE profiles. An unusual finding was the inability to obtain the MLSTallelic profile for an isolate of serotype 19A, belonging to the Sweden15A-25/ST263 clone, due to a large deletionof the xpt gene. Capsular switching was observed among both PNSSP and PSSP isolates and involved alsoserotypes not included in the 7-valent pneumococcal conjugate vaccine (PCV7), such as serotypes 15B/C and19A. Since antibiotic-resistant nonvaccine serotype clones are present in Italy, continuous monitoring ofpneumococcal epidemiology should be carried out in the PCV7 era.

Antibiotic-resistant invasive pneumococcal clones in Italy

Gherardi G;Dicuonzo G;
2007-01-01

Abstract

A total of 105 multiple-antibiotic-resistant invasive pneumococcal isolates recovered in Italy from 2001 to2003 were genetically characterized. Of these, 40 were penicillin-nonsusceptible (PNSSP) and 65 were penicillin-susceptible (PSSP) Streptococcus pneumoniae strains. Among the PNSSP isolates, 8 and 11 differentrestriction profiles were obtained for the pbp2b and pbp2x genes, respectively. Clonal groups were establishedon the basis of analysis of both pulsed-field gel electrophoresis (PFGE) types and multilocus sequence typing(MLST). Several international clones, such as Spain23F-1/ST81, Spain6B-2/ST90, Spain9V-3/ST156, andSweden15A-25/ST263, were identified among the PNSSP isolates. Other, smaller clones, such as the minorSpanish 19F clone/ST88 and Denmark14-32/ST230, were also found. Among the PSSP isolates, clones relatedto England14-9/ST9, Greece6B-22/ST273, and Portugal19F-21/ST177 were found. In addition, two large clonescomprised nonvaccine serotypes. One, comprising serotype 3 isolates, corresponded to the clone Netherlands3-31/ST180; the other, comprising serotype 15B/C isolates, ST474, was not related to any previously describedclone. Two small clusters related to the newly described clones Greece21-30/ST193 and Netherlands15B-37/ST199 included isolates with unrelated PFGE profiles. An unusual finding was the inability to obtain the MLSTallelic profile for an isolate of serotype 19A, belonging to the Sweden15A-25/ST263 clone, due to a large deletionof the xpt gene. Capsular switching was observed among both PNSSP and PSSP isolates and involved alsoserotypes not included in the 7-valent pneumococcal conjugate vaccine (PCV7), such as serotypes 15B/C and19A. Since antibiotic-resistant nonvaccine serotype clones are present in Italy, continuous monitoring ofpneumococcal epidemiology should be carried out in the PCV7 era.
File in questo prodotto:
File Dimensione Formato  
306.pdf

non disponibili

Tipologia: Altro materiale allegato
Licenza: Non specificato
Dimensione 259.97 kB
Formato Adobe PDF
259.97 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

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: https://hdl.handle.net/20.500.12610/7079
Citazioni
  • ???jsp.display-item.citation.pmc??? 8
  • Scopus 30
  • ???jsp.display-item.citation.isi??? 28
social impact