Genetic Diversity of Tn 916 -Related Transposons among Drug-Resistant Streptococcus pneumoniae Isolates Colonizing Healthy Children in Venezuela

Abstract

Among a collection of 48 multidrug-resistant pneumococcal strains colonizing healthy children in a small municipality of Mérida, Venezuela, we identified sequence types (STs) related to a variety of internationally spreading drug-resistant clones, as well as ST135, thus far isolated only in Europe. The clones invariably harbored one or more of the Tn916-related transposons Tn3872, Tn5253, Tn6002, Tn2009, and Tn2010. Finally, our data suggest both structural rearrangements in certain transposons and occurrence of novel transposable elements.

Tn916-like elements from human, oral, commensal streptococci possess a variety of antibiotic and antiseptic resistance genes

“…This study highlights the need to investigate the genetic basis for antimicrobial resistance thoroughly. Previous studies have determined the presence of Tn916-like elements based on PCR amplification of tet(M), intTn and other Tn916-like elementassociated genes [4,5]. This experimental approach risks missing important additional antibiotic resistance genes, as only known genes can be screened.…”

“…Primers for amplification of the bla ADC gene have been described previously [2], and primers FU (5 -GCG CCG TGA ATT CTT AAG TG-3 ) and RU (5 -AGC CAT ACC TGG CAC ATC AT-3 ) were used to amplify the intergenic region upstream of the bla ADC gene. PCR was performed for amplification of the quinolone resistancedetermining regions (QRDRs) of the gyrA and parC genes [4], and gene fragments were sequenced for determining specific amino acid changes. PCR for detection of the class 1 integrase gene was performed as described previously [4].…”

“…PCR was performed for amplification of the quinolone resistancedetermining regions (QRDRs) of the gyrA and parC genes [4], and gene fragments were sequenced for determining specific amino acid changes. PCR for detection of the class 1 integrase gene was performed as described previously [4].…”

Elementos genéticos móviles asociados con resistencia a eritromicina en aislamientos de Streptococcus pneumoniae en Colombia

“…Este transposón fue el más frecuente en aislamientos con diferentes serotipos (6B, 14, 23F) recuperados de muestras nasofaríngeas en Venezuela, y relacionados con varios clones internacionales (30). El mismo estudio identificó otros transposones en portadores sanos, lo cual subraya la importancia del estado del portador nasofaríngeo como reservorio de marcadores de resistencia y fuente de diseminación de clones y transposones de S. pneumoniae que pueden causar infecciones neumocócicas invasivas.…”

“…Se ha planteado la hipótesis de que el CC271 ha emergido como un grupo 'clonal' exitoso a partir un linaje del clon Taiwán 19F -ST236 que contiene el Tn2010 y presentó reemplazo del tipo capsular como respuesta a la presión selectiva de la vacuna conjugada heptavalente (31)(32)(33). El Tn2010 ha sido reportado en Estados Unidos (33), China (32,34) y Venezuela (30). El CC271 ha emergido como un clon predominante entre los aislamientos con serotipo 19A y su asociación con Tn2010 destaca su importancia en la diseminación de la multirresistencia en muchas regiones del mundo, incluido Colombia.…”