Molecular characterization of Streptococcus pneumoniae serotype 1 invasive isolates in Colombia.
OBJECTIVE
To determine the genetic relationship between Streptococcus pneumoniae serotype 1 Colombian isolates recovered from invasive disease between 1994 and 2011 and recognized serotype 1 international clones.


METHODS
A total of 135 S. pneumoniae serotype 1 isolates with epidemiological and antimicrobial susceptibility data (Clinical and Laboratory Standards Institute, 2012) were studied. The genetic relationship with recognized international clones was established by pulsed-field gel electrophoresis (PFGE) with SmaI restriction enzyme. Multilocus sequence typing (MLST) was standardized to determine the sequence type (ST) in seven isolates representing different clonal groups. Control and reference strain R6, and clones Sweden¹ ST217, Sweden¹ ST304, Sweden¹ ST306, and USA¹ ST615, were used.


RESULTS
PFGE revealed that 89.7% of the isolates were associated with Sweden¹ ST306, 3.7% were associated with Sweden¹ ST304, and 6.6% were not clonally related. Using MLST, ST306 was confirmed in six isolates and ST304 in one.


CONCLUSIONS
In contrast to Brazil and the United States, where clones Sweden¹ ST304 and ST227 prevail, invasive disease caused by S. pneumoniae serotype 1 in Colombia is principally associated with the dispersion of isolates related to clone Sweden¹ ST306.
Instituto Nacional de Salud, Bogotá, Colombia. jmoreno@ins.gov.co
Carolina
C
Duarte
Olga
O
Sanabria
Jaime
J
Moreno
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003105:Colombia; D016521:Electrophoresis, Gel, Pulsed-Field; D006801:Humans; D007223:Infant; D008875:Middle Aged; D058885:Multilocus Sequence Typing; D012703:Serotyping; D013296:Streptococcus pneumoniae / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D055815:Young Adult