Massilia sp. are non-fermentative, Gram-negative bacilli (GNB) belonging to the family Oxalobacteraceae. To our knowledge, only 8 previous cases of human infection have been reported. An 81 year-old man presented with lethargy, poor mobility and increasing confusion, temperature to 39oC, raised inflammatory markers and deranged liver function tests. A GNB grew in the aerobic bottle after 5 days. Key microbiological features were: aerobic growth on MacConkey/Blood agar (35 and 28oC), oxidase +/-, esculin +, catalase +, no growth 42oC, no growth anaerobically.
The isolate was identified as M. timonae by MALDI-TOF and this was confirmed by 16S, rRNA sequence analysis, which demonstrated 99.6-100% homology with M. timonae in NCBI and other databases. It was sensitive to Ampicillin, Ceftriaxone, Gentamicin, Ciprofloxacin and Tazobactam and resistant to Cephazolin. He was treated with Ceftriaxone then oral Augmentin with a rapid clinical response and at 3-week follow-up laboratory abnormalities had resolved.
The origin of the bacteremia is unknown. MSSU was negative and liver ultrasound showed gallstones, but no evidence of cholecystitis. The source of the organism is also unclear, but Massilia sp. appear to be environmental organisms and have been isolated from soil and water.