title: Clonal relationships among high-level penicillin-resistant Streptococcus pneumoniae in the United States.
abstract: During the past 6 to 7 years, the problem of antimicrobial resistance in Streptococcus pneumoniae has grown dramatically in the United States. Currently, approximately 26.5% of pneumococcal isolates express intermediate levels of resistance to penicillin; approximately 17.5% are highly penicillin resistant. We studied whether clonal relationships exist among current isolates of high-level penicillin-resistant S. pneumoniae (PRSP) in the United States. One hundred forty-seven PRSP isolates recovered in a 30-center surveillance study in the United States during 1994-1995 were characterized with respect to serotype, antimicrobial susceptibility pattern, and pulsed-field gel electrophoresis (PFGE) profile. Only six serotypes were observed among the 147 PRSP isolates examined in this study: 6A, 6B, 9A, 14, 19F, and 23F. One hundred three (70.1%) of the 147 strains were characterized by one of only nine PFGE types; 76 (51.7%) of the 147 isolates were characterized by only four PFGE profiles. Currently in the United States, most PRSP strains are represented by relatively few clonal groups.
authors.affiliation: University of Massachusetts Medical Center, Worcester, USA.
authors.forename: G V
authors.initials: GV
authors.lastname: Doern
authors.forename: A B
authors.initials: AB
authors.lastname: Brueggemann
authors.forename: M
authors.initials: M
authors.lastname: Blocker
authors.forename: M
authors.initials: M
authors.lastname: Dunne
authors.forename: H P
authors.initials: HP
authors.lastname: Holley
authors.forename: K S
authors.initials: KS
authors.lastname: Kehl
authors.forename: J
authors.initials: J
authors.lastname: Duval
authors.forename: K
authors.initials: K
authors.lastname: Kugler
authors.forename: S
authors.initials: S
authors.lastname: Putnam
authors.forename: A
authors.initials: A
authors.lastname: Rauch
authors.forename: M A
authors.initials: MA
authors.lastname: Pfaller
mesh_terms: D004269:DNA, Bacterial / Q000032:analysis; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D010403:Penicillin Resistance / Q000235:genetics*; D013296:Streptococcus pneumoniae / Q000145:classification / Q000187:drug effects* / Q000235:genetics; D014481:United States
chemical_list: D004269:DNA, Bacterial