[Molecular characterization of invasive isolations of penicillin-resistant Streptococcus pneumoniae recovered from adult patients]

Streptococcus pneumoniae penicillin resistance is associated with the international dispersion of specifically identified strains. In Colombia, the presence and circulation of resistant strains Spain23F-1, Spain6B-2, Spain9V and Colombian23F-25 has been demonstrated in children less than 5 years old. Strain identities were established for 80 penicillin resistant S. pneumoniae isolates recovered from Colombian adult patients. Three approaches to genotypic characterization of the strains wrere used: a) chromosomal DNA was digested with Sma 1, and the products subjected to pulse-field gel electrophoresis (PFGE); b) restriction enzyme fragment comparison of the penicillin binding protein genes (pbp 1a, 2b and 2x), and c) pneumococcal surface protein A (PspA) family. The results showed that 2.5% of the isolates were genetically related to Spain23F-1 clone, 10% to Spain6B-2 clone, 37.5% to Spain9V-3, in addition, 14% of the capsular type 23F isolates were related to the Colombia23F-25 clone and demonstrated an intermediate level resistance to penicillin. Wide spread circulation of international strains as well as a Colombian strain highlighted the importance of these clones in maintaining the prevalence of resistance to penicillin in Colombia.