Presentation
A pregnant 28-year-old woman goes into pre-term labor with identical twins (diamniotic monochorionic—1 placenta, 2 amniotic sacs) who are successfully delivered by cesarean section. The woman, who already had low platelets and elevated WBCs, progresses over the next few days to experience even more severe thrombocytopenia (37 K/uL, where a normal range is 150-400 K/uL) and elevated WBCs. Additionally, liver function tests AST, ALT, alkaline phosphatase and LDH are extremely elevated, indicating liver dysfunction, as well as evidence of kidney injury, with high creatinine and low glomerular filtration rate (GFR). Providers suspect a possible life-threatening pregnancy complication. The HELLP syndrome (hemolysis, elevated liver enzymes and low platelets), a variant or related condition to preeclampsia and thrombotic thrombocytopenia purpura (TTP) are part of the differential diagnosis. She is transferred to another facility where she receives several transfusions and plasmapheresis. She is recovering well, but on the fifth night after delivering her twins, she spikes a fever.
She has blood cultures collected and is put on a regimen of ampicillin/sulbactam. Both blood culture sets grow gram-negative rods that are not identified by the multiplex NAAT panel (BCID). On solid agar subculture, the organism grows as large, gray, moist colonies on chocolate and sheep blood agar, with no growth on MacConkey agar. Susceptibility testing by manual E-tests strips shows that it is fully resistant to meropenem, gentamicin and ceftazidime. The organism is conclusively identified by MALDI-TOF.
What could this organism be, and why it can be a serious concern for patients?
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Author Information
Richard E. Davis, Ph.D., D(ABMM), MLS(ASCP), Microbiology Director, Providence Sacred Heart Medical Center and Children’s Hospital.
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