RESUMEN
Pseudomonas aeruginosa is a versatile opportunistic pathogen capable of infecting a broad range of hosts, in addition to thriving in a broad range of environmental conditions outside of hosts. With this versatility comes the need to tightly regulate its genome to optimise its gene expression and behaviour to the prevailing conditions. Two-component systems (TCSs) comprising sensor kinases and response regulators play a major role in this regulation. This minireview discusses the growing number of TCSs that have been implicated in the virulence of P. aeruginosa, with a special focus on the emerging theme of multikinase networks, which are networks comprising multiple sensor kinases working together, sensing and integrating multiple signals to decide upon the best response. The networks covered in depth regulate processes such as the switch between acute and chronic virulence (GacS network), the Cup fimbriae (Roc network and Rcs/Pvr network), the aminoarabinose modification of lipopolysaccharide (a network involving the PhoQP and PmrBA TCSs), twitching motility and virulence (a network formed from the Chp chemosensory pathway and the FimS/AlgR TCS), and biofilm formation (Wsp chemosensory pathway). In addition, we highlight the important interfaces between these systems and secondary messenger signals such as cAMP and c-di-GMP.
Asunto(s)
Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Genes Bacterianos , Pseudomonas aeruginosa/patogenicidad , Factores de Virulencia/metabolismo , Arabinosa/análogos & derivados , Arabinosa/genética , Arabinosa/metabolismo , Proteínas Bacterianas/genética , AMP Cíclico/genética , AMP Cíclico/metabolismo , GMP Cíclico/análogos & derivados , GMP Cíclico/genética , GMP Cíclico/metabolismo , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/metabolismo , Lipopolisacáridos/metabolismo , Pseudomonas aeruginosa/genética , Factores de Virulencia/genéticaRESUMEN
Clostridium difficile (Peptoclostridium difficile) is a common health care-associated infection with a disproportionately high incidence in elderly patients. Disease symptoms range from mild diarrhea to life-threatening pseudomembranous colitis. Around 20% of patients may suffer recurrent disease, which often requires rehospitalization of patients. C. difficile was isolated from stool samples from a patient with two recurrent C. difficile infections. PCR ribotyping, whole-genome sequencing, and phenotypic assays were used to characterize these isolates. Genotypic and phenotypic screening of C. difficile isolates revealed multiple PCR ribotypes present and the emergence of rifamycin resistance during the infection cycle. Understanding both the clinical and bacterial factors that contribute to the course of recurrent infection could inform strategies to reduce recurrence. (This study has been registered at ClinicalTrials.gov under registration no. NCT01670149.).
