Providencia spp

• P. rettgeri
• P. stuartii
• P. vermicola

Less frequent:

• P. alcalifaciens
• P. heimbachae
• P. rustigianni

Gram Stain

• Gram negative bacilli - fermenter

Clinical Significance

These organisms are found in a variety of environmental sources and may be part of normal gastrointestinal flora.

They are associated with urinary tract infections in chronically catheterized patients and are difficult to eradicate due to enhanced adherence.

They can cause healthcare associated infections including bacteremia, pneumonia, and wound infections especially in debilitated or immunocompromised patients who have received prolonged antibiotic therapy.

Usual Susceptibility Pattern

These organisms produce inducible cephalosporinase (AmpC) resulting in resistance to penicillins, 1st/2nd generation cephalosporins, and beta-lactamase inhibitor combinations.

They are resistant to aminoglycosides, nitrofurantoin, and tetracyclines and have variable susceptibility to TMP/SMX and quinolones.

They are typically susceptible to carbapenems. 

Exception: Imipenem (not meropenem or ertapenem) resistance is common and due to a decreased affinity of imipenem to penicillin binding proteins (PBP2).

P. stuartii tends to be more resistant than P. rettgeri