A 34-year-old pregnant female presented to the ER with fever, backache, headache and myalgias. Blood cultures were collected and subjected to examination. Microbiological examination revealed positive motility at 25 degree Celsius and catalase positivity, Esculin positivity and positive growth in 6.5% NaCl. The colonies are as shown on blood agar plate given below. Gram Staining Which of the following is the most common route of transmission of the above organism: -
This is a case of Listeria monocytogenes infection. The blood culture plate shows beta hemolysis. The gram stain shows gram positive coco-bacilli. Most common route of infection is the GI tract. Found in processed foods. It is invasive. Produces Listeriolysin-O which allows bacterium to escape from cell membrane and cause septicemia. May cross BBB to cause meningitis and encephalitis.
Aerosol person to person transmission
Feco-oral route
Ingestion of contaminated food
Sexually transmitted
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