RESUMEN
Manganese has an important yet undefined role in the virulence of many bacterial pathogens. In this study we confirm that a null mutation in Yersinia pseudotuberculosis mntH reduces intracellular manganese accumulation. An mntH mutant was susceptible to killing by reactive oxygen species when grown under manganese-limited conditions. The mntH mutant was defective in survival and growth in macrophages expressing functional Nramp1, but in macrophages deficient in Nramp the bacteria were able to survive and replicate. In Galleria mellonella, the mntH mutant was attenuated. Taken together, these data suggest a role for manganese in Y. pseudotuberculosis during macrophage intracellular survival, protecting the bacteria from the antimicrobial products released during the respiratory burst.
Asunto(s)
Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Catión/metabolismo , Macrófagos/microbiología , Manganeso/metabolismo , Viabilidad Microbiana , Yersinia pseudotuberculosis/fisiología , Animales , Proteínas Bacterianas/genética , Proteínas de Transporte de Catión/genética , Línea Celular , Técnicas de Inactivación de Genes , Prueba de Complementación Genética , Lepidópteros/microbiología , Ratones , Estrés Oxidativo , Especies Reactivas de Oxígeno/toxicidad , Análisis de Supervivencia , Virulencia , Yersinia pseudotuberculosis/efectos de los fármacos , Yersinia pseudotuberculosis/genética , Yersinia pseudotuberculosis/metabolismoRESUMEN
The interaction between human neutrophils and the Gram negative gastrointestinal pathogen Yersinia pseudotuberculosis was investigated in vitro. Despite the wealth of data describing how Yersinia can affect the function of neutrophils, there are no published studies describing if neutrophil cells can affect the viability of Y. pseudotuberculosis. The wild-type IP32953 strain of Y. pseudotuberculosis was found to be resistant to killing by human neutrophils. Confocal examination and flow-cytometric analysis of this interaction revealed that bacteria were taken up.
Asunto(s)
Viabilidad Microbiana , Neutrófilos/inmunología , Yersinia pseudotuberculosis/inmunología , Endocitosis , Citometría de Flujo , Humanos , Microscopía ConfocalRESUMEN
We report that larvae of the wax moth (Galleria mellonella) are susceptible to infection with the human enteropathogen Yersinia pseudotuberculosis at 37 degrees C. Confocal microscopy demonstrated that in the initial stages of infection the bacteria were taken up into haemocytes. To evaluate the utility of this model for screening Y. pseudotuberculosis mutants we constructed and tested a superoxide dismutase C (sodC) mutant. This mutant showed increased susceptibility to superoxide, a key mechanism of killing in insect haemocytes and mammalian phagocytes. It showed reduced virulence in the murine yersiniosis infection model and in contrast to the wild-type strain IP32953 was unable to kill G. mellonella. The complemented mutant regained all phenotypic properties associated with SodC, confirming the important role of this metalloenzyme in two Y. pseudotuberculosis infection models.