A 62-year-old patient with high blood pressure and alcohol-related cirrhosis was admitted from the emergency department with deterioration of his general condition developing for some months. On admission, he had hypothermia and signs of severe sepsis. Laboratory tests showed biological inflammatory syndrome, acute renal failure, troponin with NTproBNP levels at 275 ng/L and 30 749 ng/L, respectively. Transoesophageal echocardiography revealed an acute endocarditis on a narrowed bicuspid aortic valve with both a vegetation and an aortic root abscess. Left ventricular ejection fraction was 30%. Blood cultures (Bact-Alert3D; BioMerieux, Marcy l'Etoile, France) were performed before amoxicillin-clavulanic acid and ceftriaxone injections. The patient was then transferred to the cardiologic ICU. Clinical examination highlighted a regular heartbeat with an inconspicuous systolic aortic murmur, left heart failure and splenomegaly with associated necrosed abscesses, pulse rate at 109/min and blood pressure at 80/49 mmHg. Despite the risk of poor evolution, the patient declined the surgery procedure and progressed to an acute respiratory distress syndrome caused by nosocomial pneumonia. Therapy was replaced by cefepime, amoxicillin-clavulanic acid and gentamicin associated with mechanical ventilation and sedation. The patient remained free from fever, CRP level and leukocytosis decreased. However, the respiratory, renal and hemodynamic functions declined rapidly, making surgery impossible. He finally died 13 days after his admission from septic shock with refractory multiple organ failure syndrome secondary to M. nonliquefaciens acute endocarditis.
Regarding microbiological documentation, five aerobic bottles sampled within the first three days of hospitalization were positive. After 24 h of culture at 37  C in Columbia agar with blood 5%, we identified M. nonliquefaciens using MALDI-TOF spectrometry mass (Bruker Daltonics, Wissembourg, France) with a score = 2.297. This phenotypical identification was confirmed by molecular 16S rRNA gene bacterial sequencing using the primers described by Gauduchon et al.. The 444 pb fragment obtained and compared with GeneBank sequences using the BLAST algorithm (http://www.ncbi.nlm.nih.gov/BLAST) showed 100% identity with M. nonliquefaciens strain V0542163 (GeneBank accession n  KC866286.1). Rapid detection of beta-lactamase by chromogenic test was positive. In vitro susceptibility tests were performed using the disc diffusion method on Mueller-Hinton blood agar (Difco, Becton Dickinson, Le Pont de Claix, France) with 5% lysed horse blood. As recommended by CA-SFM 2016 (Comite de l'Antibiogramme de la Societe Francaise de Microbiologie; http://www.sfm-microbiologie.org), the breakpoints described for Moraxella catarrhalis were used to determine the susceptibility of this bacterium. This strain was susceptible to amoxicillin-clavulanic acid, cefotaxime, erythromycin, minocycline, nalidixic acid, ciprofloxacin and resistant to trimethoprim/sulfamethoxazole.