INTRODUCTION: The scheme Kauffman-White (KW) for serotyping of Salmonella recognizes 46 O antigens, and 119 H antigens, thereby permitting the characterization of 2541 serotypes. The serotyping is a useful epidemiological tool in identifying circulating serotypes and to characterize outbreaks. However, the method presents technical limitations, difficulty in interpretation of results and high costs. OBJECTIVE: A multiplex polymerase chain reaction test (M-PCR) was developed as an alternative method for the identification of serogroups B, C2, D, and E of Salmonella enterica. MATERIALS AND METHODS: The M-PCR detected Salmonella genes rfbJ of serogroups B and C2 and wzx of serogroups D and E. To standardize the M-PCR, reference strains of Salmonella serogroups were compared. Amplification of invA gender-specific gene of Salmonella was included as internal control of amplification. To validate the test, a blind study was conducted to identify by M-PCR 400 isolates that had been previously characterized by serology. RESULTS: The M-PCR detected Salmonella serogroups with reproducible results (Kappa index = 0.95). The sensitivity of the test was between 98% to 100% and specificity between 96% to 100%. CONCLUSIONS: The polymorphisms in the Salmonella genes rfbJ and wzx permitted the development of a method for molecular typing of Salmonella serogroups that was sensitive, specific and reproducible.
INTRODUCTION: The scheme Kauffman-White (KW) for serotyping of Salmonella recognizes 46 O antigens, and 119 H antigens, thereby permitting the characterization of 2541 serotypes. The serotyping is a useful epidemiological tool in identifying circulating serotypes and to characterize outbreaks. However, the method presents technical limitations, difficulty in interpretation of results and high costs. OBJECTIVE: A multiplex polymerase chain reaction test (M-PCR) was developed as an alternative method for the identification of serogroups B, C2, D, and E of Salmonella enterica. MATERIALS AND METHODS: The M-PCR detected Salmonella genes rfbJ of serogroups B and C2 and wzx of serogroups D and E. To standardize the M-PCR, reference strains of Salmonella serogroups were compared. Amplification of invA gender-specific gene of Salmonella was included as internal control of amplification. To validate the test, a blind study was conducted to identify by M-PCR 400 isolates that had been previously characterized by serology. RESULTS: The M-PCR detected Salmonella serogroups with reproducible results (Kappa index = 0.95). The sensitivity of the test was between 98% to 100% and specificity between 96% to 100%. CONCLUSIONS: The polymorphisms in the Salmonella genes rfbJ and wzx permitted the development of a method for molecular typing of Salmonella serogroups that was sensitive, specific and reproducible.
Authors: José Luis Villarreal Camacho; Evelyn Mendoza Torres; Christian Cadena; Julieth Prieto; Lourdes Luz Varela Prieto; Daniel Antonio Villanueva Torregroza Journal: J Clin Lab Anal Date: 2013-05 Impact factor: 2.352