Finegoldia magna the cause of hip revision surgery - a two case report

The cause of septic arthritis in 20% of cases is anaerobic bacteria, including infections caused by Finegoldia magna. The occurrence of this pathogen in the etiology of postoperative post-implantive septic joint inflammations is estimated at 5-12% of all anaerobic infections, and 20-40% of all gram-positive anaerobic coccus (GPAC).

The 65-year-old male patient was admitted due to symptoms of pain in the left hip after having undergone arthroplasty three years prior. It was found that the relative length of the left lower limb was shortened by 1.5 cm and there was limited mobility of the left hip joint. The radiological image of the left hip indicated the loosening of the endoprosthesis, which qualified for a revision surgery. During hip revision surgery, the material was collected from the site, for microbiological examination, in which Finegoldia magna was detected, sensitive to Amoxicillin with Clavulanic acid, Clindamycin, Chloramphenicol, Imipenem, Metronidazole and Piperacillin with Tazobactam. Based upon the antibiogram, the patient was given piperacillin with tazobactam (Tazocin, Pfizer) 4 times a day 4.5 g intravenously over 7 days, resulting in a clinical improvement. The 55-year-old female patient was admitted due to recurrent exudates in left trochlear bursa which arose 5 years after left hip arthroplasty. The patient had limited movements in the left hip. Ulrasound diagnostics showed a presence of a thick fluid reservoir located under the fascia in the lateral side of the left thigh measuring 160 x 42 x 25 mm, which had contact with the hip joint. In the radiographic image of the joint, a cyst around the bottom of the implanted acetabular component was revealed. The patient underwent hip revision surgery, and an anaerobic bacterium Finegoldia magna was isolated from a swab taken from the acetabulum. The patient was given piperacillin with tazobactam (Tazocin, Pfizer) 4 times a day 4.5 g intravenously over 7 days, with good clinical effect.

In both cases, the post-implantation septic infection was triggered by Finegoldia magna. Arthroplasty with subsequent antibiotic therapy resulted in an improvement of the patients' condition and joint reconstruction. In orthopedic practice it should be noted that infections due to the anaerobic bacteria Finegoldia magna may be the cause of complications after the arthroplasty of the joints.