Proteus mirabilis expressing Plasmid-encoded toxin (Pet) causes urinary tract alterations

Abstract

The plasmid-encoded toxin (Pet) is one of the most studied Enterobacteriaceae autotransporters produced by the enteroaggregative Escherichia coli (EAEC). It is responsible of morphological changes in enterocytes during EAEC infection. Recently, Pet was found in the genome of the Proteus mirabilis RTX339 strain [P. mirabilis (Pet+)]. P. mirabilis causes complicated urinary tract infections (UTI) in patients having urinary catheters and structural or functional abnormalities. In this study, an UTI was induced in BALB/c female mice with the P. mirabilis (Pet+) strain. Mice infected by P. mirabilis (Pet+) showed bacterial colonization in bladder and kidney, from the second up to the tenth day post-infection. Morphological changes were evidenced by histology. Multiple exfoliated rounded cells were observed in the bladder transitional epithelium, as well as, structural cell alterations in the kidney cortex. The presence of Pet into exfoliated and parenchymal cells was confirmed by confocal microscopy. Cytoskeleton alterations were observed in those sites where Pet was detected. Pet expressed by P. mirabilis (Pet+) strain, contributes to its pathogenicity, affecting urinary tissues during the course of the infection.