What bacterium grows in refrigerated foods and causes stillbirth? A1: Listeria monocytogenes
What two toxins are key for Listeria’s intracellular escape and spread? A2: Listeriolysin O (LLO) for phagosome escape; ActA for actin polymerization. listeria sketchy
Most often acquired by eating contaminated unpasteurized dairy (soft cheeses like Brie), cold deli meats , or unwashed vegetables. What bacterium grows in refrigerated foods and causes
Why are cephalosporins ineffective against Listeria? A3: Listeria lacks penicillin-binding proteins that cephalosporins target; plus, it’s intracellular. | Sketch Element | Microbe / Feature |
| Sketch Element | Microbe / Feature | Explanation | |----------------|------------------|-------------| | | Psychrophilic (grows at 4°C) | Listeria can multiply in refrigerated foods. | | Knight in gray-green armor | Gram-positive rod | L. monocytogenes is a Gram-positive bacillus. | | Knight tumbling/rolling | Tumbling motility | Motile at room temp via flagella (looks like a somersault under microscope). | | Baby rattle | Neonatal infection | Causes granulomatosis infantiseptica & meningitis in newborns. | | Pregnancy test | Risk in pregnancy | Can cause amnionitis , septic abortion , preterm labor . | | Cheese wheel (soft cheese) | Food vehicle | Unpasteurized soft cheeses (e.g., brie, queso fresco). | | Ice cream machine behind him | Other foods | Deli meats, hot dogs, raw milk, smoked seafood. | | Mouse in corner | Animal reservoir | Rodents & ruminants carry it asymptomatically. | | Knight’s sword labeled "LLO" | Listeriolysin O | Pore-forming toxin that lyses phagosome → escapes into cytoplasm. | | Broken chains on his feet | Intracellular lifestyle | Uses actin tails (comet tails) to spread cell to cell. | | CNS helmet | Meningoencephalitis | Adults: fever, altered mental status, rhombencephalitis (brainstem signs). | | Blood droplets on floor | Bacteremia | Common in immunocompromised & elderly. |