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.

The 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 of resistance to third generation cephalosporins by Enterobacteriaceae causing community-onset urinary tract infections in hospitals in Colombia]. / Emergencia de fenotipos resistentes a cefalosporinas de tercera generación en Enterobacteriaceae causantes de infección del tracto urinario de inicio comunitario en hospitales de Colombia.

INTRODUCTION: Urinary tract infection (UTI) is a common disease in the community, and a matter of concern due to the increasing resistance of microorganisms to first line antibiotics and the emergence of multiresistant strains producing extended spectrum beta lactamases (ESBL) in the community. METHODS: An analytical case-control study was conducted over twelve months in 9 hospitals in Colombia. We collected isolates of E. coli, Klebsiella spp. and Proteus spp. from patients with community-onset UTI. The presence of ESBL, AmpC and KPC beta-lactamases were characterized by microbiological and molecular methods. The aim of this study was to determine factors related to the presence of these mechanisms of the resistance to third generation cephalosporins. RESULTS: A total of 325 isolates (287 E. coli, 29 Klebsiella spp. and 9 Proteus spp.) were included. The most frequent comorbidities among the patients were hypertension (n=82; 25.2%) and diabetes mellitus (n=68; 20.9%). Previous use of antimicrobials was found in 23% of patients, and 29% had a previous UTI. Resistance to third and fourth generation cephalosporins varied between 3.4% and 6.3% in E. coli and between 6.9% and 17.8% in K. pneumoniae. Seven (2.4%) CTX-M-15 ESBL-producing E. coli isolates were detected; four of them belonged to ST 131 clone. In K. pneumoniae we detected three KPC-3 carbapenemases (10.3%). CONCLUSIONS: This study confirms the emergence of resistance to third generation cephalosporins enterobacteriaceae as a cause of community-onset UTI. We emphasize the presence of ST 131 clone and KPC carbapenemases circulating in Colombia outside the hospital environment.

Design of two molecular methodologies for the rapid identification of Colombian community-acquired methicillin-resistant Staphylococcus aureus isolates.

INTRODUCTION: Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are found with increasing the frequency, both in healthy individuals in the community and in hospitalized patients. In Colombia and the Andean region, CA-MRSA isolates have a genetic background that is related to the pandemic USA300 clone. OBJECTIVE: Two molecular methods are designed and standardized for the rapid differentiation of Colombian community-acquired and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates. MATERIALS AND METHODS: Two molecular methods were standardized for the identification of CA-MRSA isolates. The first method was based on the differential digestion of the carbamate kinase (arcC)and guanylate kinase (gmk) genes in the sequences type 5 (ST5) in the HA-MRSA isolates and 8 (ST8) in the CA-MRSA isolates. The second method was based on the PCR amplification of 5 specific virulence factors found in CA-MRSA and HA-MRSA isolates. The specificity and precision of each method were evaluated using 237 clinical MRSA isolates. RESULTS: The first method identified 100% and 93.2% of the CA-MRSA and HA-MRSA isolates, respectively. The second method also correctly identified the two isolates types (CA-MRSA and HA-MRSA). CONCLUSIONS: These two methods are a convenient alternative for the rapid identification of the CA-MRSA isolates, compared with other techniques such as pulsed field gel electrophoresis and multilocus sequence typing, which are time-consuming and more expensive.

[Methicillin-resistant Staphylococcus aureus colonization in a Colombian hospital intensive care unit: phenotypic and molecular characterization]. / Colonización por Staphylococcus aureus resistente a la meticilina en una unidad de cuidados intensivos de adultos de un hospital colombiano: caracterización fenotípica y molecular con detección de un clon de circulación en la comunidad.

INTRODUCTION: Methicillin-resistant Staphylococcus aureus (MRSA) cause nosocomial and community infections. MRSA colonization in hospitals has been described as an important risk factor during hospitalization. OBJECTIVE: The colonization characteristics of MRSA was described using the tools of molecular biology. MATERIALS AND METHODS: Between February 2007 and February 2008, 705 patients entering a Colombian intensive care unit (ICU) were screened for MRSA by taking nasopharyngeal samples. For 683 of these patients, a weekly follow-up was provided after they left the ICU. The susceptibility of each S. aureus isolate was tested against 11 antibiotics using agar dilution methods. Sixty two percent (62.0%) of the MRSA isolates were characterized at genetic and molecular level with the detection of resistant genes, SCCmec typing using PCR and the genetic profile with pulsed field gel electrophoresis (PFGE). RESULTS: Of the 705 patients screened at entry to the ICU, 182 (25.8%) were colonized by S. aureus, and of these, 51 (7.2%) were MRSA. Of the 683 patients with follow-up, 62 (9.1%) were infected by MRSA contracted in the hospital ICU. The prevalence of the Chilean clone was 76.5% at entry and 88.9% for follow-up patients. Of the 113 patients colonized with MRSA, nosocomial infection was present in 18 patients (16.0%). Three community-acquired MRSA isolates related to the USA300-0114 pandemic clone were identified. These were also positive for Panton-Valentine leucidin cytotoxin genes of S.aureus. CONCLUSIONS: This is the first report in Colombia of patients colonized with CA-MRSA-ST8-SCCmec IVc isolates, and it is a probable source of dissemination of this bacteria in Colombian hospitals.

Design of two molecular methodologies for the rapid identification of Colombian community-acquired methicillin-resistant Staphylococcus aureus isolates / Diseño de dos metodologías moleculares para la rápida identificación de aislamientos de Staphylococcus aureus resistente a meticilina asociados a la comunidad en Colombia

Introduction. Community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are found with increasing the frequency, both in healthy individuals in the community and in hospitalized patients. In Colombia and the Andean region, CA-MRSA isolates have a genetic background that is related to the pandemic USA300 clone. Objective. Two molecular methods are designed and standardized for the rapid differentiation of Colombian community-acquired and hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates. Materials and methods. Two molecular methods were standardized for the identification of CA-MRSA isolates. The first method was based on the differential digestion of the carbamate kinase (arcC)and guanylate kinase (gmk) genes in the sequences type 5 (ST5) in the HA-MRSA isolates and 8 (ST8) in the CA-MRSA isolates. The second method was based on the PCR amplification of 5 specific virulence factors found in CA-MRSA and HA-MRSA isolates. The specificity and precision of each method were evaluated using 237 clinical MRSA isolates. Results. The first method identified 100% and 93.2% of the CA-MRSA and HA-MRSA isolates, respectively. The second method also correctly identified the two isolates types (CA-MRSA and HA-MRSA). Conclusions. These two methods are a convenient alternative for the rapid identification of the CA-MRSA isolates, compared with other techniques such as pulsed field gel electrophoresis and multilocus sequence typing, which are time-consuming and more expensive.

Introducción. Los aislamientos de Staphylococcus aureus resistente a la meticilina asociado a la comunidad (SARM-AC), están aumentando la frecuencia de infecciones en personas sanas de la comunidad y en pacientes hospitalizados. En Colombia y en la región andina estos aislamientos tienen un componente genético relacionado con el clon pandémico USA300. Objetivo. Diseñar y estandarizar dos metodologías para la diferenciación rápida de aislamientos colombianos de S. aureus resistente a la meticilina asociado a la comunidad de los asociados al hospital (SARM-AH). Materiales y métodos. Se estandarizaron dos metodologías moleculares para la identificación de aislamientos de S. aureus resistente a la meticilina asociado a la comunidad. La primera se basa en la digestión diferencial con tres enzimas de restricción de los genes cinasa de carbamato (arcC)y cinasa de guanilato (gmk)para los tipos de secuencia 5 (ST5) y 8 (ST8), correspondientes a aislamientos de S. aureus resistente a la meticilina asociado al hospital y asociado a la comunidad, respectivamente. La segunda se basa en la amplificación por reacción en cadena de la polimerasa de cinco factores de virulencia que se encuentran de manera diferencial en estos aislamientos. Las dos metodologías fueron validadas en 237 aislamientos clínicos de S. aureus resistente a la meticilina. Resultados. Con la primera metodología se identificaron el 100 % y 93,2 % de los aislamientos de S. aureus resistente a la meticilina asociado a la comunidad y asociado al hospital, respectivamente. Con la segunda metodología se identificaron correctamente los dos tipos de aislamientos. Conclusiones. Estas dos metodologías son una buena alternativa en términos de ahorro en tiempo y dinero comparadas con otras técnicas, como la electroforesis en campo pulsado y la tipificación de secuencias multilocus para la rápida identificación de aislamientos de S. aureus resistente a la meticilina asociado a la comunidad en Colombia.

Colonización por Staphylococcus aureus resistente a la meticilinaen una unidad de cuidados intensivos de adultos de un hospitalcolombiano: caracterización fenotípica y molecular con detecciónde un clon de circulación en la comunidad / Methicillin-resistant Staphylococcus aureus colonization in a Colombian hospital intensive care unit: phenotypic and molecular characterization

Introducción. Staphylococcus aureus resistente a la meticilina (SARM) causa infecciones adquiridas en la comunidad y en el ámbito hospitalario. El ser portador de SARM se ha descrito como factor de riesgo para desarrollar infección clínica. Objetivo. Caracterizar la colonización por SARM en pacientes adultos de una unidad de cuidados intensivos colombiana, utilizando herramientas de biología molecular.Materiales y métodos. Entre febrero de 2007 y febrero de 2008 se tamizaron mediante hisopado nasofaríngeo, 705 pacientes al ingresar a la unidad de cuidados intensivos, de los cuales, 683 (96,9%) fueron seguidos semanalmente y al egreso de la unidad. Se determinó el perfil de sensibilidad de los aislamientos a 11 antibióticos por el método de dilución en agar; el 62,0% de los aislamientos de SARM fueron caracterizados genética y molecularmente. Resultados. Se tamizaron 705 pacientes al ingreso; 182 (25,8%) estaban colonizados por S. aureus, de los cuales, 51 (7,2%) eran resistentes a la meticilina. Se hizo el seguimiento durante la estancia en la unidad de cuidados intensivos a 683 pacientes, de los cuales, 62 (9,1%) fueron colonizados por SARM en dicha unidad. La prevalencia del clon chileno fue de 76,5% al ingreso y de 88,9% durante la estancia. El 16,0% de los pacientes colonizados desarrollaron algún tipo de infección por SARM. Se encontraron tres pacientes colonizados con SARM adquirido en la comunidad, los cuales fueron positivos para la leucocidina Panton-Valentine (Panton-Valentine leukocidin, PVL). Conclusiones. El 7,2% de los pacientes que ingresaron a la unidad de cuidados intensivos estaban colonizados con SARM. Éste es el primer reporte de colonización por aislamientos de SARM-ST8-SCCmec IVc adquirido en la comunidad y relacionado genéticamente con el clon pandémico USA300-0114 en Colombia.

Introduction. Methicillin-resistant Staphylococcus aureus (MRSA) cause nosocomial and community infections. MRSA colonization in hospitals has been described as an important risk factor during hospitalization. Objective. The colonization characteristics of MRSA was described using the tools of molecular biology. Materials and methods. Between February 2007 and February 2008, 705 patients entering a Colombian intensive care unit (ICU) were screened for MRSA by taking nasopharyngeal samples. For 683 of these patients, a weekly follow-up was provided after they left the ICU. The susceptibility of each S. aureus isolate was tested against 11 antibiotics using agar dilution methods. Sixty two percent (62.0%) of the MRSA isolates were characterized at genetic and molecular level with the detection of resistant genes, SCCmec typing using PCR and the genetic profile with pulsed field gel electrophoresis (PFGE). Results. Of the 705 patients screened at entry to the ICU, 182 (25.8%) were colonized by S. aureus, and of these, 51 (7.2%) were MRSA. Of the 683 patients with follow-up, 62 (9.1%) were infected by MRSA contracted in the hospital ICU. The prevalence of the Chilean clone was 76.5% at entry and 88.9% for follow-up patients. Of the 113 patients colonized with MRSA, nosocomial infection was present in 18 patients (16.0%). Three community-acquired MRSA isolates related to the USA300-0114 pandemic clone were identified. These were also positive for Panton-Valentine leucidin cytotoxin genes of S.aureus. Conclusions. This is the first report in Colombia of patients colonized with CA-MRSA-ST8-SCCmec IVc isolates, and it is a probable source of dissemination of this bacteria in Colombian hospitals.

Emergencia de fenotipos resistentes a cefalosporinas de tercera generación en Enterobacteriaceae causantes de infección del tracto urinario de inicio comunitario en hospitales de Colombia / Emergence of resistance to third generation cephalosporins by Enterobacteriaceae causing community-onset urinary tract infections in hospitals in Colombia

Introducción La infección del tracto urinario (ITU) es una patología frecuente, de gran preocupación por la resistencia creciente de los microorganismos causantes frente a los antibióticos de primera línea y la aparición de cepas resistentes productoras de betalactamasas de espectro extendido en la comunidad. Métodos Estudio analítico tipo casos y controles de 12 meses, en 9 hospitales de Colombia. Se analizaron aislamientos de Escherichia coli, Klebsiella spp. y Proteus spp. de pacientes con ITU de inicio comunitario. Se determinó la presencia de betalactamasas de espectro extendido, AmpC y KPC por métodos microbiológicos y moleculares. Se establecieron factores relacionados con la presencia de estos mecanismos de resistencia a cefalosporinas de tercera generación. Resultados Se recolectaron 325 aislamientos (287 E. coli, 29 Klebsiella spp. y 9 Proteus spp.). Las comorbilidades más frecuentes fueron hipertensión arterial (n=82; 25,2%) y diabetes mellitus (n=68; 20,9%). Se encontró consumo previo de antibióticos en el 23% y antecedente de ITU previa en el 29%. La resistencia a cefalosporinas de tercera y cuarta generación varió entre el 3,4 y el 6,3% para E. coli y entre el 3,4 y el 17,2% para K. pneumoniae.Se detectó CTX-M-15 en 7 aislamientos de E. coli (2,4%), 4 pertenecientes al clon ST131. En K. pneumoniae se detectaron 3 aislamientos positivos para KPC-3(10,3%).ConclusiónSe confirma la emergencia de enterobacterias resistentes a cefalosporinas de tercera generación como causa de ITU de inicio comunitario. Se resalta la circulación en Colombia del clon ST 131 y carbapenemasas tipo KPC en pacientes fuera del ambiente hospitalario (AU)

Introduction Urinary tract infection (UTI) is a common disease in the community, and a matter of concern due to the increasing resistance of microorganisms to first line antibiotics and the emergence of multiresistant strains producing extended spectrum beta lactamases (ESBL) in the community. Methods An analytical case-control study was conducted over twelve months in 9 hospitals in Colombia. We collected isolates of E. coli, Klebsiella spp. and Proteus spp. from patients with community-onset UTI. The presence of ESBL, AmpC and KPC betalactamases were characterized by microbiological and molecular methods. The aim of this study was to determine factors related to the presence of these mechanisms of the resistance to third generation cephalosporins .Results A total of 325 isolates (287 E. coli, 29 Klebsiella spp. and 9 Proteus spp.) were included. The most frequent comorbidities among the patients were hypertension (n=82; 25.2%) and diabetes mellitus (n=68; 20.9%). Previous use of antimicrobials was found in 23% of patients, and 29% had a previous UTI. Resistance to third and fourth generation cephalosporins varied between 3.4% and 6.3% in E. coli and between 6.9% and 17.8% in K. pneumoniae. Seven (2.4%) CTX-M-15 ESBL-producing E. coli isolates were detected; four of them belonged to ST 131 clone. In K. pneumoniae we detected three KPC-3 carbapenemases (10.3%). Conclusions This study confirms the emergence of resistance to third generation cephalosporins enterobacteriaceae as a cause of community-onset UTI. We emphasize the presence of ST 131 clone and KPC carbapenemases circulating in Colombia outside the hospital environment (AU)