Ruminococcus gnavus Total Hip Arthroplasty Infection in a 62-Year-Old Man with Ulcerative Colitis

Abstract

We report the case of a total hip arthroplasty infection caused by Ruminococcus gnavus in a 62-year-old man with ulcerative colitis. The bacterium was perfectly identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry. CASE REPORTA 62-year-old man was referred to the orthopedic surgery department of a suburban clinic with suspected prosthetic joint infection (PJI) of the right hip. This patient had undergone total right hip replacement 13 years earlier and had shown no signs of prosthesis dysfunction since surgery.On admission, the patient presented with right hip pain and fever. Biological tests showed elevated white blood cell (18.3 ϫ 10 9 cells/liter) and C-reactive protein (137 mg/liter) levels. No blood culture was collected. Radiological evaluation of the total hip arthroplasty showed a 5-mm subsidence of the femoral stem.Three bone biopsies were performed with a notch needle, and the samples were sent to the microbiology laboratory of the Hôpi-taux Universitaires Paris Ile de France Ouest, Greater Paris, for microbiological analysis. Samples were processed as previously described (1), with continuously monitored broth enrichment. Briefly, samples were topped with 17 ml sterile distilled water and bead milled for 150 s on a Retsch MM300 mixer mill (Verder, France) with 10 to 15 5-mm-diameter stainless steel beads. One hundred microliters of the resulting suspension, plated on 5% sheep blood Columbia agar medium, was incubated for 5 days at 36°C under aerobic and anaerobic conditions, and 6 ml was injected into Bactec Peds Plus and Lytic/10 Anaerobic/F blood culture vials supplemented with a fastidious organism supplement incubated for 14 days in a Bactec FX automated blood culture system (BD Diagnostics, Le Pont de Claies, France). Microscopic examination of the three biopsy samples showed an absence of erythrocytes, numerous polymorphonuclear cells, and Grampositive cocci in short chains. No empirical antibiotic therapy was started after the biopsy. All samples yielded positive cultures on anaerobic medium, with a time to detection of 7 h 7 min for all three Lytic/10 Anaerobic/F vials. On day 1, growth was detected on anaerobic blood agar plates, with numerous translucent small colonies. The diplococci were identified by mass spectrometry (Biotyper version 3.1 on a Microflex LT mass spectrometer, Bruker Daltonics, Bremen, Germany) as Ruminococcus gnavus, with a score of 2.2, and later confirmed by 16S rRNA gene sequencing using previously described primers (2). A 16S rRNA gene fragment of 407 bp was amplified from the bacteria and sequenced on an Applied Biosystems genetic analyzer. GenBank database searches showed the amplified sequences to be 99% (404/ 407 bp) identical to the 16S rRNA gene sequence of the reference strain for R. gnavus ATCC 29149 (GenBank accession no. KP407134). Antimicrobial susceptibility testing by the agar disk diffusion method (Bio-Rad, Marnes-la-Coquette, France) using Comité de l'Antibiogramme de la Société Française de Microbiologie (CA-SFM 20...

A novel Ruminococcus gnavus clade enriched in inflammatory bowel disease patients

“…In addition to its increased abundance in IBD, other studies have implicated R. gnavus as a potential pathobiont. Three cases of R. gnavus bacteremia and a case of infection of the bone surrounding a hip implant by R. gnavus have been reported [ 28 – 30 ]. In a study about treating UC patients with fecal microbiome transplants, patients who received stool from donors with high R. gnavus were more likely to relapse [ 31 ], suggesting a causal role in disease.…”

Association between gut microbiota, bone metabolism, and fracture risk in postmenopausal Japanese women

“…Butyrate-producing bacteria are promising probiotic candidates targeting microbiota modulation in gastrointestinal disorders such as IBD [ 16 ]. Similarly, Ruminococcus gnavus , a member of the Ruminococcaceae family, has been reported to be implicated in infection following artificial hip joint replacement [ 17 ], liver abscess due to Ruminococcus gnavus , and infective endocarditis. In addition, reports have shown that Ruminococcus is involved in the development of cerebral and myocardial infarction [ 18 ].…”

Ruminococcus gnavus bacteraemia in a patient with multiple haematological malignancies

“…Ruminococcus gnavus is a strict anaerobic Gram-positive coccus, which has been described as being part of the normal intestinal flora in humans [1]. To date, only nine cases of R. gnavus infections have been reported in the literature, predominantly in patients with gastrointestinal symptoms or prosthesis infection [2][3][4][5][6][7][8][9]. We present the first case of R. gnavus bacteraemia in a patient with multiple haematological malignancies, and with no abdominal complaint or prosthesis infection.…”

“…Of the nine cases found, six involved patients with a background of gastrointestinal (GI) diseases such as diverticular disease, ulcerative colitis and cholecystitis [2][3][4][5][6], and one more was hypothesized to have had a GI fistula [7]. In four of the cases, the bacteria were found in a hip (native or alloplastic) [4,[7][8][9]. See Table 1 for further information on previous cases.…”