Caracterización molecular de aislamientos invasores colombianos de Streptococcus pneumoniae serotipo 5 recuperados entre 1994 y 2004.

BACKGROUND: Streptococcus pneumoniae serotype 5 is an important cause of invasive disease in Colombia where the circulation of the clone Colombia5-19, penicillin susceptible but tetracycline and chloramphenicol resistant, has been demonstrated. OBJECTIVE: To establish the genetic relatedness among Colombian invasive S. pneumoniae serotype 5 isolates, recovered between 1994 and 2004, and the clone Colombia(5)-19. MATERIALS AND METHODS: Eighty three isolates with penicillin, vancomycin, ceftriaxone, erythromycin, trimethoprim-sulfametoxazole, chloramphenicol and tetracycline susceptibility patterns were studied. Of these isolates, 29 were recovered from children less than 5 years of age. DNA restriction patterns of all isolates were determined for pulsed field gel electrophoresis, using the Smal enzyme. Genetic similarity among isolates and the clone Colombia(5)-19 was established according to Tenover's criteria and the Fingerprintingä II program. RESULTS: All isolates were related with the Colombia(5)-19 clone and belonged to the electrophoretic pattern A, of which 17 subtypes were derived. Most of the isolates belonged to patterns A (38,6%), A8 (21,7%) and A5 (12%), the other 23 isolates belonged to 15 electrophoretic patterns. Thirty -four isolates resistant both to tetracycline and chloramphenicol were related with electrophoretic patterns A (n = 32), A16 (n = 1) and A28 (n = 1), which have a band of 340 Kb in common with the clone. CONCLUSION: These results showed the continuing circulation of S pneumoniae serotype 5 isolates in the country, and which are genetically related with the clone Colombia(5)-19.