title: Serotype and clonal evolution of penicillin-nonsusceptible invasive Streptococcus pneumoniae in the 7-valent pneumococcal conjugate vaccine era in Italy.
abstract: The percentage of invasive penicillin-nonsusceptible pneumococci (PNSSP) isolated in Italy in the seven-valent pneumococcal conjugate vaccine (PCV7) era moderately increased in comparison to the pre-PCV7 era. Increase of nonvaccine serotypes was observed among PNSSP. The most frequent PNSSP clones were the same as those identified in the pre-PCV7 era, although they were present in different proportions. Clonal expansion, emergence of new clones, and acquisition of penicillin resistance by established clones contributed to the maintenance of penicillin resistance.
authors: Centro Integrato di Ricerche, Laboratory of Microbiology, Università Campus Biomedico, Rome, Italy.
authors: Giovanni
authors: G
authors: Gherardi
authors: Fabio
authors: F
authors: D'Ambrosio
authors: Daniela
authors: D
authors: Visaggio
authors: Giordano
authors: G
authors: Dicuonzo
authors: Maria
authors: M
authors: Del Grosso
authors: Annalisa
authors: A
authors: Pantosti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D060965:Clonal Evolution / Q000235:genetics*; D002999:Clone Cells; D006801:Humans; D007558:Italy; D010403:Penicillin Resistance / Q000235:genetics; D010406:Penicillins / Q000494:pharmacology*; D011008:Pneumococcal Infections / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D022242:Pneumococcal Vaccines / Q000008:administration & dosage / Q000276:immunology*; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D018074:Vaccines, Conjugate
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D022242:Pneumococcal Vaccines; D018074:Vaccines, Conjugate