Comamonas spp

• C. aquatica
• C. kerstersii
• C. terrigena
• C. testosteroni

Gram Stain

• Gram negative straight/slightly curved bacilli- nonfermenter (aerobic)

Clinical Significance

These organisms are found in a variety of environmental sources, including soil, water, and hospital environments. 

Although of low pathogenic potential, they have been associated with bacteremia (medical device related), peritonitis, psoas abscesses, appendicitis, salpingitis, endocarditis, nosocomial pneumonia, and ocular infections.

Comamonas spp have a predilection for intra-abdominal infections. Polymicrobial infections are common. They may be recovered from respiratory specimens of cystic fibrosis patients.

 

Usual Susceptibility Pattern

These organisms are often resistant to aminoglycosides, penicillins, and 1st/2nd generation cephalosporins. 

They are usually susceptible to 3rd generation cephalosporins, beta-lactamase inhibitor combination drugs, carbapenems, quinolones, tetracyclines, and TMP/SMX.

Empiric Therapy
Ciprofloxacin
or
Ceftriaxone
or
TMP/SMX