Which organism is a gram-positive rod that grows in the cold, can cause meningitis in pregnant or immunocompromised individuals, and is linked to unpasteurized dairy products and soft cheese?

Which organism is a gram-positive rod that grows in the cold, can cause meningitis in pregnant or immunocompromised individuals, and is linked to unpasteurized dairy products and soft cheese?

• A. Listeria monocytogenes
• B. Staphylococcus aureus
• C. Escherichia coli
• D. Streptococcus pneumoniae

Answer: (A)

Grows in the cold and causes meningitis in pregnant or immunocompromised individuals, with a clear link to unpasteurized dairy and soft cheeses, point to Listeria monocytogenes. This gram-positive rod is notable for its ability to multiply at refrigeration temperatures, a trait that helps it survive in dairy products and other refrigerated foods. In pregnant people, in those with weakened immune systems, and in newborns, it can invade the bloodstream and meninges, leading to meningitis or fetal/newborn infection after placental transmission. Lab-wise, you’d expect to see gram-positive rods, and clinically it’s a known foodborne pathogen associated with soft cheeses and unpasteurized dairy products. Other organisms listed are either not gram-positive rods, or they don’t grow well at cold temperatures or have the same pregnancy-focused meningitis risk linked to dairy.

Grows in the cold and causes meningitis in pregnant or immunocompromised individuals, with a clear link to unpasteurized dairy and soft cheeses, point to Listeria monocytogenes. This gram-positive rod is notable for its ability to multiply at refrigeration temperatures, a trait that helps it survive in dairy products and other refrigerated foods. In pregnant people, in those with weakened immune systems, and in newborns, it can invade the bloodstream and meninges, leading to meningitis or fetal/newborn infection after placental transmission. Lab-wise, you’d expect to see gram-positive rods, and clinically it’s a known foodborne pathogen associated with soft cheeses and unpasteurized dairy products. Other organisms listed are either not gram-positive rods, or they don’t grow well at cold temperatures or have the same pregnancy-focused meningitis risk linked to dairy.