Taxonomy
Family: Morganellaceae

P. alcalifaciens
- P. rustigianii (P. alcalifaciens biogroep 3)
P. rettgeri
P. stuartii

apathogeen P. heimbachae, P. vermicola

Natural habitats
They are ubiquitous in the environment, especially water and clinical samples, such as; urine, feces, blood, wounds and throat. Also occur in animals, mammals, birds, reptiles and insects.

Clinical significance
Patients who develop Providencia urinary tract infections often have long-standing dependence on an indwelling urinary catheter.

P. alcalifaciens, P. rustigianii, and P. heimbachae

Infections with these Providencia species are most likely to elicit gastrointestinal symptoms.

P. alcalifaciens infection is also associated with overseas travel.