16th February 2025

A 38-year-old lady attends the Emergency Department with difficulty breathing, neck swelling, mouth pain and voice change.

A 38-year-old lady attends the Emergency Department with difficulty breathing, neck swelling, mouth pain and voice change. These symptoms have progressed over one day and have been preceded by tooth ache lasting one week, for which she has not yet seen a dentist.

On examination, she had bilateral submandibular swelling, erythema and woody induration. She is developing stridor and is severely distressed.

Observations: respiratory rate 28, saturations 97% on room air, pulse 125, blood pressure 95/59, temperature 38.8°C.

CT of her neck shows soft tissue swelling and focal fluid collection in the submandibular space.

What is the most likely causative organism?

Select the SINGLE most appropriate option from the list below. Select ONE option only.