Identification of the autotransporter Pet toxin in Proteus mirabilis strain isolated from patients with urinary tract infections

Abstract

Proteus mirabilis, a motile Gram-negative bacterium, represents a common cause of complicated urinary tract infections. Autotransporters are a family of secreted proteins from Gram-negative bacteria that direct their own secretion across the outer membrane (type V autotransporter secretion mechanism). Serine protease autotransporters of Enterobacteriaceae (SPATEs) include adhesins, toxins, and proteases that can contribute to the virulence. Plasmid-encoded toxin (Pet) is the predominant protein in culture supernatants of enteroaggregative E. coli prototype strain 042 and has been extensively studied. Pet toxin is encoded on the 65-MDa adherence-related plasmid of EAEC 042 strain. In this work, Pet protein was found in the supernatant obtained from Proteus mirabilis RTX339 strain isolated from a psychiatric patient suffering complicated urinary tract infections (UTIs). The nucleotide sequence of pet gene was obtained using primers designed from E. coli 042 pet gene reported. The alignment of the sequence showed 100% identity with the pet gene reported. Is important to note that Proteus mirabilis RTX339 pet gene has chromosomal location. The chromosomal location of the gene was established since no plasmids were harbored by this strain.