Elizabethkingia meningosepticum: an emerging nosocomial pathogen in a critical patient with septicaemia

We describe a case of sepsis due to the non-fermenter Gram-negative bacillus Elizabethkingia meningosepticum in a patient (M, 23 y.o.) hospitalized at the Intensive Care and Critical Care Medicine suffering of a severe neurological disease and acute surgical abdomen, caused by suppurative peritonitis secondary to PEG removal. Two sets of blood cultures were collected at the time of persistent fever. The culture on chocolate and blood agar showed the presence of colonies with characteristic grey-shiny appearance and 1-2 mm in diameter. No growth was instead evident on Mac-Conkey agar. The Gram stain was performed, but the final identification of the isolate as E. meningosepticum was obtained by Vitek2 System, on the basis of growth characteristics, biochemical reaction results, and the peculiar antibiotic susceptibility profile. The identification was also confirmed by Vitek MS MALDI-TOF mass spectrometry instrument (bioMérieux, Marcy-l’Étoile, France). Results of susceptibility testing highlighted the resistance to most antibiotics useful against Gram-negative bacteria and a paradoxical susceptibility to those targeting mainly Gram-positives. The vancomycin and ciprofloxacin combined therapy improved the patient’s conditions, with a complete resolution of the E. meningosepticum bacteraemia. Unfortunately, due to the onset of important clinical and surgical complications, the patient died as a result of a septic shock caused by a MDR Acinetobacter baummannii. The present work underline the importance of correct species identification in the case of E. meningosepticum, a rare bacterium whose unique antimicrobial susceptibility pattern, require an ad hoc therapeutic approach.