Ostéite du trapèze à Ralstonia pickettii : à propos d'un cas et revue de la littérature

A case of meningitis caused by Ralstonia insidiosa, a rare opportunistic pathogen

BACKGROUND

Ralstonia is a genus of Gram-negative opportunistic bacteria that can survive in many kinds of solutions and cause a variety of infections. Ralstonia spp. have increasingly been isolated and reported to cause infections in recent years, thanks to the development of identification methods such as matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and gene sequencing. However, infections caused by Ralstonia insidiosa are still rare. Only a few cases of respiratory infections and bloodstream infections have been reported, none of which involved meningitis. To the best of our knowledge, this is the first reported case of meningitis caused by R. insidiosa worldwide. It is necessary to report and review this case.

CASE PRESENTATION

We report a case of meningitis caused by R. insidiosa following lumbar surgery in China. The patient exhibited symptoms of headache, dizziness, and recurrent fever. The fever remained unresolved after empiric antibiotic therapy with intravenous cefotaxime and vancomycin in the initial days. Cerebrospinal fluid (CSF) culture yielded Gram-negative non-fermentative bacteria, which were identified as R. insidiosa. As there was a lack of antibiotic susceptibility testing results, clinical pharmacists conducted a literature review to select appropriate antibiotics. The patient's condition improved after receiving effective treatment with intravenous cefepime and levofloxacin.

CONCLUSIONS

Uncommon pathogens, such as R. insidiosa, should be considered in postoperative central nervous system (CNS) infections, particularly in cases with unsatisfactory results of empiric anti-infective therapy. This is the first reported case of meningitis caused by R. insidiosa worldwide. MALDI-TOF MS provides rapid and accurate identification of this pathogen. The antibiotic susceptibility testing results of R. indiosa may be interpreted based on the breakpoints for Pseudomonas spp., Burkholderia cepacia spp., and Acinetobacter spp. Our case presents a potential option for empiric therapy against this pathogen, at least in the local area. This is crucial to minimize the severity and mortality rates associated with meningitis. Standardized antibiotic susceptibility testing and breakpoints for the Ralstonia genus should be established in the future as cases accumulate. Cefepime and levofloxacin may be potential antibiotics for infections caused by R. indiosa.

Osteomyelitis Caused by Ralstonia mannitolilytica, a Rare Opportunistic Pathogen

Ralstonia spp. are non-fermenting aerobic gram-negative rods found in humid environments, whose role as opportunistic human pathogens has lately been recognized. Ralstonia mannitolilytica is one of the three members of the Ralstonia genus (together with Ralstonia pickettii and Ralstonia insidiosa). Bone infections by Ralstonia spp. are very rare. We report a case of femoral osteomyelitis caused by R. mannitolilytica. Among literature search, only eight cases of bone infection due to the Ralstonia genus have been described, in all of which the causative agent was identified as R. pickettii. To our knowledge, this is the first reported case of osteomyelitis attributed to R. mannitolilytica. Despite its low virulence, Ralstonia has specific characteristics that promote its spread and shows high antibiotic resistance, partly due to its ability to create a biofilm. Identification of Ralstonia spp. poses unique difficulties as the distinction between the species of the genus is not straightforward. Additionally, the bacteria may be misidentified as other closely related species. Recent data suggests that modern spectrometry and gene sequencing techniques are essential to avoid these pitfalls. Susceptibility data about the genus is limited and based on a small number of case reports, therefore there is no standardized antibiotic susceptibility testing and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints exist. The report aims is to provide useful information on the antibiotic selection and treatment suggestions to be followed for bone infections caused by the Ralstonia genus, along with a review on the literature of this emerging opportunistic pathogen.

Ralstonia pickettii bacteremia in a cardiac surgery patient in Belgrade, Serbia

Ralstonia pickettii is an opportunistic bacterium found in the water environment with an increasing incidence as a nosocomial pathogen. The objectives of this study were to describe R. pickettii bacteremia in a cardiac surgery patient and to evaluate its ability to grow in a saline solution and to form biofilm. The patient in this study underwent mitral and aortic valve replacement surgery with two aortocoronary bypasses. She developed signs of respiratory and renal failure, therefore hemodialysis was started. After 25 days in an intensive care unit, the patient had recurrent episodes of fever with signs of bacteremia. R. pickettii was identified from blood cultures by MALDI-TOF MS. Antimicrobial susceptibility testing was performed using disc diffusion and broth microdilution methods in accordance with EUCAST methodology and results were interpreted following clinical breakpoints for Pseudomonas spp. The isolate was susceptible to all tested antimicrobial agents except aminoglycosides and colistin. Survival of R. pickettii was analyzed in saline solution with four different starting concentrations at 25 °C and 37 °C for six days. Biofilm capacity was tested using the microtiter plate method. R. pickettii showed substantial growth in saline solution, with starting concentration of 2 CFU ml-1 reaching 107 CFU ml-1 after six days. There was no significant difference between growth at 25 °C and 37 °C. This indicates that storage of contaminated solutions at room temperature can enhance the count of R. pickettii. Our strain did not show the capacity to form biofilm. The patient responded well to adequate treatment with ceftazidime, and after 48 days in ICU she was discharged to convalesce.

Sonication contribution to identifying prosthetic joint infection with Ralstonia pickettii: a case report and review of the literature

Background

In the context of an increase number of primary and revision total hip and total knee arthroplasty performed yearly, an increased risk of complication is expected. Prosthetic joint infection (PJI) remains the most common and feared arthroplasty complication. Ralstonia pickettii is a Gram-negative bacterium, that has also been identified in biofilms. It remains an extremely rare cause of PJI. There is no report of an identification of R. pickettii on an extracted spacer loaded with antibiotic.

Case presentation

We present the case of an 83-years-old Caucasian male patient, that underwent a right cemented total hip replacement surgery. The patient is diagnosed with an early PJI with no isolated microorganism. A debridement and change of mobile parts is performed. At the beginning of 2016, the patient in readmitted into the Orthopedic Department for sever, right abdominal and groin pain and elevated serum erythrocyte sedimentation rate and C-reactive protein. A joint aspiration is performed with a negative microbiological examination. A two-stage exchange with long interval management is adopted, and a preformed spacer loaded with gentamicin was implanted. In July 2016, based on the proinflammatory markers evolution, a shift a three-stage exchange strategy is decided. In September 2016, a debridement, and changing of the preformed spacer loaded with gentamicin with another was carried out. Bacteriological examination of the tissues sampled intraoperatively was positive for Pseudomonas aeruginosa. From the sonication fluid, no bacteria were isolated on culture or identified using the bbFISH assay. During the hospitalization period, the patient received i.v. ceftazidime 3x2g/day and p.o. ciprofloxacin 2x750mg/day, antibiotic therapy that was continued after discharge with p.o. ciprofloxacin 2x750mg/day for 6 weeks. In February 2017, a reimplantation of a revision prosthesis is performed. The retrieved spacer is sonicated, and after 4 days of incubation of the sonication fluid, R. pickettii is isolated. A long term antibiotic therapy with cotrimoxazole being prescribed.

Conclusions

Bacteria culture of sonication fluid remains the gold standard in diagnosing prosthetic joint infections. R. pickettii remains an extremely rare cause of prosthetic joint infection. Optimal management of R. pickettii prosthetic joint infections of has not been established.

Native Valve Endocarditis due to Ralstonia pickettii: A Case Report and Literature Review

Ralstonia pickettii is a rare pathogen and even more rare in healthy individuals. Here we report a case of R. pickettii bacteremia leading to aortic valve abscess and complete heart block. To our knowledge this is the first case report of Ralstonia species causing infective endocarditis with perivalvular abscess.