Final answer:
Proteus mirabilis primarily causes urinary tract infections and is known for its swarming motility and antibiotic resistance, complicating treatment.
Step-by-step explanation:
The Proteus mirabilis bacterium is known to primarily cause urinary tract infections (UTIs). This opportunistic pathogen is part of the Enterobacteriaceae family and can also contribute to the formation of kidney stones due to its ability to produce urease, which raises urine pH and leads to the precipitation of kidney stone components. While Proteus mirabilis is one of many antigens that can cause urinary tract infections, it is particularly noted for its characteristic swarming motility on agar plates and its resistance to many standard antibiotics, posing challenges in clinical settings.