Raoultella spp

• R. ornithinolytica
• R. planticola
• R. terrigena

Gram Stain

• Gram negative bacilli - fermenter

Clinical Significance

These organisms are widely distributed in nature.

R. ornithinolytica – found in aquatic environments and rarely causes human infection. It has been associated with diabetic foot wounds, brain abscesses, meningitis, osteomyelitis, pneumonia, urinary tract, cellulitis, hepatobiliary / medical device related infections, and enteric fever. This organism is similar biochemically to Klebsiella oxytoca.

R. planticola – is similar in pathogenicity to K. pneumoniae. It is associated with bacteremia, osteomyelitis, urinary tract and medical device related infections following invasive procedures in immunocompromised patients.

R. terrigena – an aquatic and soil organism. Human infections are rare.

Usual Susceptibility Pattern

Raoultella spp. produce a chromosomal Class A penicillinase and are intrinsically resistant to all penicillins (despite in vitro susceptible results).

They are typically susceptible to beta lactamase inhibitor combinations, aminoglycosides, quinolones, and nitrofurantoin. 

Susceptibility to TMP/SMX, and tetracycline is variable. These organisms are predictably resistant to fosfomycin.