Detection of a New Community Genotype Methicillin-Resistant Staphylococcus aureus Clone That Is Unrelated to the USA300 Clone and That Causes Pediatric Infections in Colombia

Abstract

dThe dissemination of a clone of community genotype methicillin-resistant Staphylococcus aureus (CG-MRSA) that is related to USA300 has been reported in Latin America. We recently detected isolates of a new clone of CG-MRSA (spa type t1635 and ACME-negative) that was genetically unrelated to the USA300 clone and that causes infections in children in Colombia. This finding indicates the appearance of a new clone of CG-MRSA in our region.

Emergence and spread of a new community-genotype methicillin-resistant Staphylococcus aureus clone in Colombia

“…The molecular characterization of the 32 CG-MRSA isolates demonstrated that they all harboured SCC mec IVa (IV.1.1.1), were of spa type t1635 (YHGFMBO) and presented a 54-bp insertion in the sausa300_0808 gene in S. aureus pathogenicity island 5 (SaPI5). These same features were previously found in the COL923 isolates recovered from paediatric infections in Bogota, Colombia [ 13 ]. All isolates harboured the sek and seq genes within SaPI5.…”

“…This particular region contains an ORF that encodes a putative transposase. Although the SCC mec IVa element in the COL923 clone still has high nucleotide identity (>98%) with the SCC mec IVa element in the USA300 clone, our results show that it has also acquired certain foreign DNA fragments [ 12 , 13 ]. These results reinforce the idea that the new variant (COL923) has gained DNA fragments and support the importance of further studies aimed at increasing our understanding of this process.…”

“…Between 2008 and 2011, the prevalence of this clone was reported to comprise 70% and 90% of MRSA infections in adults and paediatric patients, respectively [ 6 , 11 , 30 ], in several Colombian cities. However, in 2010, we identified eight CG-MRSA isolates with different molecular and genetic characteristics compared to the USA300-LV clone but with similarity to the COL923 clone [ 12 , 13 ]. Our data showed that the COL923 (CG-MRSA-IVa-ST923) clone had also been causing infections in children in other regions of Colombia (outside Bogota) since 2009.…”

“…In recent years, the frequency of this MRSA-IVc clone has increased among MRSA infections both in the community and in hospitalized patients, replacing traditional HG-MRSA clones (e.g., Chilean and Brazilian clones) [ 11 , 12 ]. We recently reported the detection of eight isolates belonging to a new CG-MRSA clone that have caused paediatric infections in Bogota, Colombia [ 13 ]. These isolates were found to possess SCC mec IVa and a spa type t1635; to belonged to the ST923 (a single-locus variant of ST8); to possess an Sma I-restriction pulsed-field gel electrophoresis (PFGE) pulsotype that is not related to that of the USA300 clone (>6 bands of difference); and to lack an ACME, which is frequently found in the USA300 clone.…”

Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia?

“…La diseminación de aislamientos SASM-USA300 y su probable capacidad de adquirir SCCmec puede estar contribuyendo al aumento de la frecuencia de infecciones causadas por el clon SARM-USA300, reportado en nuestro país en el 2006 y que ya es causante de aproximadamente 94 y 60 % de las infecciones en población pediátrica y de adultos, respectivamente (8,10,45,46 Es necesario seguir el estudio de este fenómeno y profundizar en el posible origen de nuestros aislamientos SARM para llevar a cabo la vigilancia epidemiológica y los estudios clínicos no solo de los SARM sino de los SASM, pues en muchas ocasiones se subestiman debido a que su tratamiento antibiótico es mucho más fácil y efectivo, pero podrían ser el reservorio de aislamientos más patógenos y virulentos como se ha descrito con relación al USA300.…”