Comparison of PCR-based molecular markers for the characterization of Proteus mirabilis clinical isolates.

Proteus mirabilis is one of the most important pathogens associated with complicated urinary tract infections (acute pyelonephritis, bladder infections, kidney stones) and bacteremia, affecting patients with anatomical abnormalities, immunodeficiency, and long-term urinary catheterization. For epidemiological purposes, various molecular typing methods, such as pulse-field gel electrophoresis (PFGE) or ribotyping, have been developed for this pathogen. However, these methods are labor intensive and time-consuming. We evaluated the discriminatory power of several PCR-based fingerprinting methods (RAPD, ISSR, ERIC-PCR, BOX-PCR and rep-PCR) for P. mirabilis clinical isolates. Typing patterns and clustering analysis indicated that RAPD, BOX-PCR and ERIC-PCR differentiated P. mirabilis strains from Escherichia coli, Hafnia alvei, and Morganella morganii. With the exception of rep-PCR, the methods gave medium to high discriminatory efficiency in P. mirabilis. In general, the results obtained with RAPD, BOX-PCR and ERIC-PCR were in good agreement. We concluded that a combination of ERIC-PCR and BOX-PCR results is a rapid and reliable alternative for discrimination among P. mirabilis clinical isolates, contributing to epidemiological studies.