Clonal relationships among high-level penicillin-resistant Streptococcus pneumoniae in the United States.
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.
Doern
G V
GV
University of Massachusetts Medical Center, Worcester, USA.
Brueggemann
A B
AB
Blocker
M
M
Dunne
M
M
Holley
H P
HP
Kehl
K S
KS
Duval
J
J
Kugler
K
K
Putnam
S
S
Rauch
A
A
Pfaller
M A
MA
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
D004269:DNA, Bacterial