Case of the Month: January 2026

Clinical history

Ms. B is a previously healthy 26-year-old female admitted to the Royal Victoria Regional Health Center in Barrie with fever, productive cough, and dyspnea. She takes no medications, has no allergies, and has received all routine childhood and adult vaccinations. She has an 8 pack-year smoking history. She is employed as a general labourer for a local construction firm. She has never travelled outside of the Georgian Bay area.

On presentation, her vitals are as follows: BP 85/50, HR 135, RR 25, SpO2 86% on room air, Tmax 38.5°C. She is confused and has crackles to the left lung base on auscultation. Chest x-ray shows a large, left lower lobe opacity. She is placed on supplementary oxygen by high-flow nasal cannula and started on empiric ceftriaxone plus azithromycin. Blood cultures, sputum cultures, and nasal swab for respiratory virus PCR are collected.

Over the next 12 hours, Ms. B continues to decline. She is unable to maintain her oxygen saturation and is therefore intubated. Norepinephrine and vasopressin are initiated due to persistent hypotension despite fluid resuscitation. Her antibiotics are broadened to meropenem and vancomycin. Blood work is significant for a white blood cell count of 18 (predominantly neutrophils), a hemoglobin of 80 g/L, a creatinine of 150 umol/L, an AST of 70 IU/L, and an ALT of 90 IU/L. Repeat chest imaging now demonstrates new bilateral patchy opacities. Given her unstable hemodynamic status, she is transferred to the Toronto General Hospital ICU.

Upon arrival, the ICU team performs a bronchoalveolar lavage and collects repeat blood cultures. You (the Microbiologist on-call) are paged by the ICU staff, who fills you in on the above story and says: “We don’t know what is going on, but she is very sick. She isn’t responding to her antibiotics. Her blood cultures and respiratory virus PCR from RVRHC were negative, and her sputum culture was rejected by their lab! Can you process this BAL as a stat test?” You speak to the laboratory staff in the Microbiology specimen receiving area, who assure you that they will plant the BAL fluid on all routine plates for bacterial culture and will have a gram stain prepared for the Respiratory bench within an hour of specimen receipt. 45 minutes later, you are pulled aside by the Respiratory bench technologist who says “Myself and another MLT reviewed that gram stain, but we aren’t sure what we are looking at. Can you take a look?”

Questions:

1. What are three criteria (observable by gram stain) that are used by the microbiology laboratory to determine if a sputum specimen is appropriate for bacterial culture, and why are these criteria in place?

2. The above gram stain shows an organism that will require urgent communication to the ICU team, as well as your laboratory staff.

   a. What feature(s) suggest that this is not a typical bacterial pneumonia?

   b. What actions might you ask your microbiology staff perform to ensure we can safely identify this organism (for bonus points, what is this organism)?

   c. What might you recommend the ICU team do in terms of empiric antimicrobial therapy for this patient?

3. What is meant by the term “Risk Group” and how does the concern for a Risk Group 3 or Risk Group 4 organism impact how specimens are worked on in a diagnostic Microbiology Lab?

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