Providencia rettgeri (commonly P. rettgeri), is a Gram negative bacterium that is commonly found in both water and land environments. P. rettgeri is in the genus Providencia, along with Providencia stuartii, , and . P. rettgeri can be incubated at 37 °C in nutrient agar or nutrient broth. It was first discovered in 1904 after a waterfowl epidemic. Strains of the species have also been isolated from nematodes of the genus Heterorhabditis.