Case of the Month - May 2020
A 3-week-old girl was hospitalized with high fever, fussiness, and rhinorrhea. She had been born via normal spontaneous vaginal delivery to a mother with gestational diabetes and colonization with group B streptococcus, for which she received appropriate intrapartum prophylaxis.
The baby was fussy but had no conjunctivitis or rash and reacted normally to others. She tested positive for SARS-CoV-2 and was started on prophylactic empiric treatment with ceftriaxone, ampicillin, and acyclovir because of the fever. A lumbar puncture was performed but not sufficient for performing cell counts.
Twenty-four hours after hospitalization, she developed ulcerations in the mouth including the buccal mucosa, with diminished oral intake, and had fevers to 39.5°C. CSF cultures sent after antibiotic administration were negative. RT-PCR of CSF and oral lesions was negative for viruses.
Gram-negative bacilli started to grow from a blood culture. Grey colonies were recovered on blood agar but there was no growth on MacConkey plates. The organism was oxidase-positive and despite being Gram-negative, it was susceptible to vancomycin. What is the organism?
Growth on blood agar with a zone of inhibition around a vancomycin disk.
No growth on MacConkey agar.