Providencia is a genus of facultatively anaerobic, Gram-negative, motile, bacteria that belong to the tribe Proteae, Enterobacteriaceae family. It was formerly classified as part of the Proteus genus. The genus Providencia was named after Providence, Rhode Island, where C.A. Stuart worked on these bacteria.

Providencia species have been isolated from patients stools, urinary tract infections, wounds, burns, blood, and sewage contaminated natural waters. P. rustigianii has been confirmed as a GI tract inhabitant and is often found in the intestinal tracts of mammals, such as humans and pigs, and even in penguins. Providencia species have also been isolated from patients with pneumonia, meningitis, and endocarditis 3.

Scanning electron micrograph (SEM) of Gram-negative Providencia alcalifaciens bacteriaImage Provider: CDC/Pete Wardell

Providencia Species Are Carbapenem-resistant Enterobacteria (CRE)

Although the genus Providencia contains five species, only three species have been clearly identified as pathogens: P. stuartii, P. rettgeri, and P. alcalifaciens. The most virulent human pathogen is P. stuartii which often colonizes urinary catheters leading to bacteremia. The species manifests an extraordinary ability to persist within the catheterized urinary tracts; bacteriuria may take weeks or even months to clear. This species and P. rettgeri are resistant to many common antibiotics, including penicillins, first-generation cephalosporins, aminoglycosides, tetracyclins, sulfamethoxazole, carbapenems, and fosfomycin. Cases of P. stuartii septicemia are usually fatal due to antibiotic resistance 1,4,5. Carbapenem-resistant enterobacteria are important for a number of reasons. First, these organisms are often resistant to multiple classes of antimicrobials substantially limiting treatment options. Second, infections caused by these organisms are associated with high mortality rates, 40% to 50% in some studies 6.

Although P. alcalifaciens used to be considered as a commensal of the GI tract, recent reports have documented that the organism is an invasive intestinal pathogen and a recognized cause of gastroenteritis. The species possesses a protective mechanism enabling it to evade the immune system and survive inside the intestinal and macrophage cells, as Salmonella and Yersinia does 2


  1. Martin Dworkin, Stanley Falkow. The Prokaryotes: Proteobacteria: gamma subclass
  2. Dongyou Liu. Molecular Detection of Human Bacterial Pathogens
  3. Paul G. Engelkirk, Janet Duben-Engelkirk. Laboratory Diagnosis of Infectious Diseases
  4. Julia A. McMillan, Ralph D. Feigin. Oski's Pediatrics: Principles & Practice
  5. Notes from the Field: Detection of blaNDM-1 Carbapenem Resistance in a Clinical Isolate of Providencia stuartii in a U.S./Coalition Medical Facility
  6. Carbapenem-resistant Enterobacteriaceae (CRE) Infection: Clinician FAQs



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