Streptobacillus moniliformis

Gram Stain

• Gram variable straight bacilli with bulbar swelling small to medium sized (facultative anaerobic)

Clinical Significance

This organism causes rat bite fever, a systemic illness of fever, maculopapular rash, and migratory polyarthritis (sometimes suppurative).

Complications include endocarditis, pericarditis, septicemia, pneumonia, and abscesses.

Usual Susceptibility Pattern

This organism is susceptible to penicillins, cephalosporins, carbapenems, tetracyclines, clindamycin, and macrolides.

It is resistant to TMP/SMX and colistin and has variable susceptibility to aminoglycosides and quinolones.