A 23-year-old black woman was admitted to the hospital in premature labor with intact amniotic membranes. The patient was afebrile and did not have any obvious signs of infection. Gram stain of the amniotic fluid, obtained via transabdominal amniocentesis, revealed the presence of gram-negative rods. The bacterium was identified as Streptobacillus moniliformis, the agent of rat-bite fever.