Infective endocarditis related to the uncommon gram-negative pathogen Sphingobacterium spiritivorum

Abstract

Volume 4: 1-3 10,800/uL) with neutrophilia (neutrophils 85%), and C reactive protein of 289 mg/L, and normal renal (serum creatinine 0.9 mg/dL) and liver function tests. A transoesophageal echocardiography revealed mitral valve prolapse, and an image suggesting mitral valve vegetation with moderate to severe grade regurgitation, and chordal rupture. Antibiotic (oxacylin) was changed to vancomycin and meropenem. During the follow up, patient’s clinical picture deteriorated, and pulmonary rales progressed up to upper lung levels. The patient was then taken to the operating room emergently where he had a mitral valve replacement. Intraoperative histopathological results of the mitral valve indicated marked acute inflammation, fibroinflammatory debris, and presence of Gram-negative rod. After two days of incubation of mitral valve debris, non-motile, oxidase positive, non-fermenting Gram-negative bacilli grew, identified as Sphingobacterium spiritivorum (Vitek 2, bioMérieux, Marcy-L’Etóile, France), and confirmed using the Vitek MS -MALDI-TOF (Matrix Assisted Laser Desorption Ionization – Time of Flight, bioMérieux, Marcy-L’Etóile, France). Antimicrobial susceptibility testing was performed by automated microdilution broth method (Vitek 2). The results were reported as the minimal inhibitory concentration – MIC (CLSI Table 2B-5, M 100-S25-2015) [6], according to breakpoint criteria: ceftazidime (MIC < 4 μg/mL), cefepime (MIC < 4 μg/mL), imipenem (MIC < 0.5 μg/mL), meropenem (MIC ≤ 0.25 μg/ mL), piperacillin/tazobactam (MIC < 8 μg/mL), ciprofloxacin (MIC MIC ≤ 0.25 μg /mL), and sulfamethoxazole/trimethoprim (MIV MIC ≤20 μg/mL). Finally, like other flavobacteria-like organisms, it was highly resistant to colistin, amikacin and gentamicin. Piperacillin/ tazobactam was associated to antibiotic treatment. He had no fever and his clinical picture was improved. Five weeks after surgical intervention, a new transoesophageal echocardiography did not show any evidence of vegetation or abscess. However, after two weeks the patient condition deteriorated, with fever, and haemodynamic instability. Blood cultures grew Acinetobacter baumannii. On the 40th day, the patient died of septic shock.