RESUMO
Chronic carriers of Salmonella Typhi act as reservoirs for the organism and become the agents of typhoid outbreaks in a community. In this study, chronic carriers in Kelantan, Malaysia were first identified using the culture and polymerase chain reaction method. Then, a novel serological tool, designated Typhidot-C, was evaluated in retrospect using the detected individuals as control positives. Chronic carriage positive by the culture and polymerase chain reaction method was recorded at 3.6% (4 out of 110) among individuals who previously had acute typhoid fever and a 9.4% (10 out of 106) carriage rate was observed among food handlers screened during outbreaks. The Typhidot-C assay was able to detect all these positive carriers showing its potential as a viable carrier screening tool and can be used for efficient detection of typhoid carriers in an endemic area. These findings were used to establish the first carrier registry for S Typhi carriers in Malaysia.
Assuntos
Portador Sadio/epidemiologia , Sistema de Registros/estatística & dados numéricos , Salmonella typhi/isolamento & purificação , Febre Tifoide/epidemiologia , Fezes/microbiologia , Manipulação de Alimentos , Humanos , Técnicas Imunoenzimáticas , Malásia/epidemiologia , Reação em Cadeia da PolimeraseRESUMO
Vibrio parahaemolyticus produces a thermostable direct haemolysin (TDH) that has been implicated in the pathogenesis of diarrhoeal disease caused by this organism. In previous work, TDH induced Cl- secretion in human colonic epithelial cells that was dependent on the intracellular Ca2+ concentration, [Ca2+]in. This study investigated whether Cl- secretion induced by TDH is influenced by the stage of maturation of intestinal epithelial cells. Two different human colonic cell lines, villus cell-like Caco-2 cells and crypt cell-like T84 cells, cultured by different methods to obtain differentiated samples, were used. When these cells were exposed to butyrate, a transcriptional regulator of differentiation genes, or co-cultured with 18Co cells, a human colonic fibroblast cell line, they showed increased trans-epithelial resistance and villus cell marker enzyme activity. In Caco-2 cells, exposure to butyrate or co-culturing with 18Co cells resulted in increased TDH binding, higher short-circuit currents (Isc) and greater [Ca2+]in. These results suggest that sensitivity to TDH is affected by the stage of cellular differentiation of cultured intestinal epithelial cells.