Case 89

1. Presented by Dr. Alice Meiss MD and Dr. Patricia Simner MSc PhD

An elderly immunosuppressed patient is admitted due to new onset altered mental status in the setting of hypertension (systolic blood pressure to the 190s mmHg). Brain imaging is negative for an acute intracranial abnormality. The patient is currently on a course of IV cefepime due to a recent diagnosis of pneumonia. Laboratory work-up on admission is remarkable for:

WBC 2.41 K/mm^3 (Normal diff)
Hg/Hct: 10.0 g/dL / 30.5%
Platelets: 71 K/mm^3

After 48 hours, microbiology studies obtained on admission show:

Bacterial/Yeast Culture, Blood (PICC Line): Gram Negative Bacilli in Aerobic Bottle

Sabouraud agar plates show colonies with a pink, mucoid, "slimy" appearance.

Further history was gathered, and the patient reported recently cleaning their PICC line with something other than an alcohol swab. The line was removed and the antibiotic was changed to meropenem.

What is the most likely causative pathogen?