Comparison of results generated by serotyping, pulsed-field restriction analysis, ribotyping, and repetitive-sequence PCR used to characterize penicillin-resistant pneumococci from the United States

One hundred forty-seven isolates of Streptococcus pneumoniae with high-leve l penicillin resistance collected during a national surveillance program in the United States were characterized by serotyping, pulsed-held restrictio n analysis, ribotyping, and repetitive-sequence (BOX element) PCR. The resu lts generated by each method were compared by frequency of association to e xamine whether relationships existed between the various typing methods and statistically to determine association with the geographic source of the i solate or the age of the patient from whom the isolate was obtained. When t he data were examined by pairwise analysis of individual strain classificat ions produced by each typing method, no statistically significant relations hips between strain type, geographic location, or patient age were identifi ed, suggesting that distinct clones of penicillin-resistant S. pneumoniae h ave been widely distributed throughout the United States. However, we did o bserved shared expression of two or three typing markers at a high frequenc y (> 50%) among clusters of strains, indicating a certain level of concorda nce between the various typing methods used to classify penicillin-resistan t S. pneumoniae.