Dispersión intercontinental de una cepa de Shigella flexneri resistente a trimetoprima | Enfermedades Infecciosas y Microbiología Clínica

Article information

Introducción

Caracterizar una cepa de Shigella flexneri resistente a trimetoprima, aislada de las heces de un viajero a su retorno de Kenia, y analizar su relación epidemiológica con un conjunto de cepas de similares características aisladas en Tanzania

Métodos

Las relaciones clonales se estudiaron mediante análisis del perfil plasmídico, secuencias extragénicas palindrómicas repetidas-reacción en cadena de la polimerasa (REP-PCR) y electroforesis en geles de campos pulsantes (PFGE). Se estudió la presencia de integrones tipo 1mediante reacción en cadena de la polimerasa (PCR) y secuenciación. Mediante técnicas de conjugación y PCR se analizó la localización y transferabilidad del integrón detectado

Resultados

Los estudios epidemiológicos mostraron que el total de seis cepas estudiadas pertenecían a un mismo clon. Asimismo, todas ellas poseían el mismo gen codificante para resistencia a trimetoprima (dfrA7), el cual estaba localizado en un integrón situado a nivel cromosómico

Conclusiones

Es preciso mantener una vigilancia epidemiológica para controlar la difusión de microorganismos patógenos, o de genes de resistencia, entre áreas geográficas distantes

Palabras clave:

Trimetoprima

Resistencia

dfrA7

Viajeros

Diseminación clonal

Introduction

Intercontinental spread of a trimethoprim-resistant strain of Shigella flexneri. In this study we characterize a trimethoprim-resistant strain of Shigella flexneri recovered from stool samples of an international traveler after a trip to Kenya, and analyze its epidemiological relationship with a set of strains having similar characteristics from Tanzania

Methods

Clonal relationships were studied by three techniques - plasmid profile, repetitive-element (REP)-PCR and pulse-field gel electrophoresis (PFGE). The presence of type 1 integrons was studied by PCR and sequencing. The location and transferability of the detected integron was analyzed by conjugation and PCR

Results

The epidemiological studies showed that all six strains studied belonged to the same clone. Furthermore, all of them carried the same gene encoding for trimethoprim resistance (dfrA7), which was located in an integron within a chromosome

Conclusion

Continuous epidemiological surveillance is required to control the spread of pathogenic microorganisms and the dissemination of resistance-encoding genes among geographical areas

Key words:

Trimethoprim

Resistance

dfrA7

Travelers

Clonal spread

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