RESUMEN

A nested multiplex polymerase chain reaction (PCR) based diagnosis was developed for the detection of virulent Salmonella typhi in the blood specimens from patients suspected for typhoid fever. After the Widal test, two pairs of primers were used for the detection of flagellin gene (fliC) of S. typhi. Among them, those positive for fliC alone were subjected to identification of genes in Via B operon of Salmonella Pathogenesity Island (SPI-7) where four primer pairs were used to detect tviA and tviB genes. Among 250 blood samples tested, 115 were positive by fliC PCR; 22 of these were negative for tviA and tviB. Hence, the method described here can be used to diagnose the incidence of Vi-negative serovar typhi especially in endemic regions where the Vi vaccine is administered.

Asunto(s)

Sangre/microbiología , Reacción en Cadena de la Polimerasa Multiplex/métodos , Salmonella typhi/aislamiento & purificación , Salmonella typhi/patogenicidad , Fiebre Tifoidea/diagnóstico , Proteínas Bacterianas/genética , Cartilla de ADN , ADN Bacteriano/sangre , Femenino , Flagelina/genética , Islas Genómicas/genética , Humanos , Masculino , Técnicas de Diagnóstico Molecular/métodos , Operón , Salmonella typhi/genética , Sensibilidad y Especificidad , Factores de Transcripción/genética , Fiebre Tifoidea/microbiología , Vacunas Tifoides-Paratifoides , Virulencia