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

Ralstoniapickettii bloodstream infection in the patient with Guillain-Barre syndrome under plasmapheresis

Ralstonia pickettii is a rare Gram-negative opportunistic bacterium that causes rare infections such as bacteremia, neonatal sepsis, endocarditis, and meningitis in hospitalized or immunocompromised patients. In this study, we identified and reported bloodstream infection caused by R. pickettii in a 15 -year-old boy patient with an autoimmune disease, Guillain-Barré syndrome, under plasmapheresis and intravenous immune globulin (IVIG) therapy. He was referred for admission to the neurology center of the teaching hospital of Shiraz, Iran for inability to walk, and lower extremity muscle weakness. After he was treated with plasmapheresis once during hospitalization, and after severe fever besides shivering blood cultures using BACT/ALERT®3D instrument were positive for R. pickettii.According to antibiotic susceptibility test reports, Ciprofloxacin (5 μg) was prescribed. Fortunately, after starting antibiotic treatment, blood culture results reported no growth after 5 days. Indeed, the patient was infected with nosocomial hepatitis A and URSOBIL (300 mg/BID/Po) was administered. Hence, after reporting the infection occurrence to the hospital infection control unit, initial and possible measures such as device infection control, replacement of potentially polluted plasmapheresis fluids, disinfecting the environment and replacing old sterile washing water with new sources were carried out in plasmapheresis unit. In conclusion, R. pickettii is a rare nosocomial infection that is responsible for the contamination of medical equipment, especially in hemodialysis, plasmapheresis devices and sterile solutions. Also, it is suggested that the role and importance of rare environmental bacteria as the causative agents of human infections should not be ignored in medical centers.

Alterations of the gut microbiome and metabolic profile in CVB3-induced mice acute viral myocarditis

BACKGROUND

Acute viral myocarditis (AVMC) is an inflammatory disease of the myocardium. Evidence indicates that dysbiosis of gut microbiome and related metabolites intimately associated with cardiovascular diseases through the gut-heart axis.

METHODS

We built mouse models of AVMC, then applied 16 S rDNA gene sequencing and UPLC-MS/MS metabolomics to explore variations of gut microbiome and disturbances of cardiac metabolic profiles.

RESULTS

Compared with Control group, analysis of gut microbiota showed lower diversity in AVMC, decreased relative abundance of genera mainly belonging to the phyla Bacteroidetes, and increased of phyla Proteobacteria. Metabolomics analysis showed disturbances of cardiac metabolomics, including 62 increased and 84 decreased metabolites, and mainly assigned to lipid, amino acid, carbohydrate and nucleotide metabolism. The steroid hormone biosynthesis, cortisol synthesis and secretion pathway were particularly enriched in AVMC. Among them, such as estrone 3-sulfate, desoxycortone positively correlated with disturbed gut microbiome.

CONCLUSION

In summary, both the structure of the gut microbiome community and the cardiac metabolome were significantly changed in AVMC. Our findings suggest that gut microbiome may participate in the development of AVMC, the mechanism may be related to its role in dysregulated metabolites such as steroid hormone biosynthesis.

Ralstonia mannitollylitica endocarditis: A case report

Ralstonia mannitolilytica (R. mannitolilytica.) is an emerging aerobic Gram-negative bacteria causing infection among immunocompromised patients. R. mannitolilytica, has been described in hospital outbreaks, mainly as bloodstream infection, but also as meningitis, hemoperitoneum infection and post renal transplant infection. We describe the first reported case of R. mannitolilytica infective endocarditis.

A case of persistent bacteraemia by Ralstonia mannitolilytica and Ralstonia pickettii in an intensive care unit

The Ralstonia spp. genus is a group of non-fermentative, Gram-negative bacteria often resistant to many antibiotics, which are emerging as opportunistic pathogens frequently associated with infections in hospital settings. We present herein a case of combined R. pickettii and R. mannitolilytica persisting and relapsing bacteraemia, possibly caused by a septic arterial thrombosis secondary to the rupture of an internal carotid artery aneurysm. Microbiology studies showed that both Ralstonia isolates produced biofilm and carried class D oxacillinase genes. When confronted with infections caused by members of the Ralstonia genus, identification to the species level is crucial for correct clinical management, as the two species show different antibiotic susceptibility patterns.

Ralstonia pickettii Bacteremia: An Emerging Infection in a Tertiary Care Hospital Setting

Ralstonia species are Gram-negative bacilli that have increasingly been recognized as emerging nosocomial pathogens, particularly in immunocompromised hosts. Ralstonia pickettii is the most clinically important pathogen from the Ralstonia genus. Nosocomial outbreaks of Ralstonia pickettii infections brought about by the use of contaminated medical solutions, including saline, sterile water, as well as disinfectants, have been reported. There have been case reports of invasive infections with variable presentations. Here, we describe three cases of Ralstonia pickettii bacteremia during a period of one year in a tertiary care hospital in Karachi, Pakistan. The first case was a 76-year-old male, known case of type 2 diabetes mellitus (DM), hypertension, and amyotrophic lateral sclerosis, who presented with complaints of burning micturition, hematuria, and fever. The patient had a history of multiple hospital admissions in the recent past. His blood culture was found to be positive for Ralstonia pickettii. A computed tomography scan of the kidneys, ureter, and bladder (CT KUB) was suggestive of pyelonephritis. The patient improved on intravenous meropenem. The second case was a 47-year-old man, who was admitted with a gunshot injury to the neck, resulting in complete cervical cord resection and mild hydrocephalus with intraventricular hemorrhage. The patient had a prolonged intensive care unit (ICU) stay, which was complicated by ventilator-associated pneumonia with Acinetobacter and central line-associated bloodstream infection (CLABSI) with Ralstonia pickettii. He was treated with meropenem and colistin but continued to deteriorate and expired. The third case was a 46-year-old lady, known case of end-stage renal disease (ESRD), who was admitted with prosthetic valve endocarditis. She had a prolonged hospital stay complicated by CLABSI with Ralstonia pickettii, improved on meropenem, but later died due to fungemia. Ralstonia pickettii is an emerging cause of nosocomial infection in patients, particularly those with a prolonged hospital stay, and can cause invasive and severe infections.

Accurate identification and epidemiological characterization of Burkholderia cepacia complex: an update

Bacteria belonging to the Burkholderia cepacia complex (Bcc) are among the most important pathogens isolated from cystic fibrosis (CF) patients and in hospital acquired infections (HAI). Accurate identification of Bcc is questionable by conventional biochemical methods. Clonal typing of Burkholderia is also limited due to the problem with identification. Phenotypic identification methods such as VITEK2, protein signature identification methods like VITEK MS, Bruker Biotyper, and molecular targets such as 16S rRNA, recA, hisA and rpsU were reported with varying level of discrimination to identify Bcc. rpsU and/or 16S rRNA sequencing, VITEK2, VITEK MS and Bruker Biotyper could discriminate between Burkholderia spp. and non-Burkholderia spp. Whereas, Bcc complex level identification can be given by VITEK MS, Bruker Biotyper, and 16S rRNA/rpsU/recA/hisA sequencing. For species level identification within Bcc hisA or recA sequencing are reliable. Identification of Bcc is indispensable in CF patients and HAI to ensure appropriate antimicrobial therapy.

An outbreak of Ralstonia pickettii endophthalmitis following intravitreal methotrexate injection

Purpose

To report an outbreak of endophthalmitis in three eyes of two patients following intravitreal methotrexate, caused by Ralstonia pickettii.

Design

Retrospective, noncomparative, consecutive case series.

Methods

Medical records and microbiology results of two patients who presented with acute endophthalmitis following intravitreal methotrexate injection in November 2013 were reviewed.

Results

Following intravitreal injections, the patients experienced pain and decrease in vision in the affected eye within 24 hours of receiving intravitreal methotrexate injection. The presenting visual acuity in case 1 was 20/50 in the left eye. The presenting visual acuity in case 2 was hand motions in the right eye and counting fingers at 1 m in the left eye. Both the patients received methotrexate prepared in the same manufacturing facility. Both the patients underwent vitreous biopsy and intravitreal injection of vancomycin 1 mg/0.1 mL, amikacin 400 µg/0.1 mL, and dexamethasone 400 µg/0.1 mL. Microbiology cultures from vitreous, and used and unused vials of methotrexate from the same batch grew R. pickettii. After 8 months of follow-up, both the patients had visual acuity 20/60 or better.

Conclusion

R. pickettii can be rarely associated with outbreak of endophthalmitis. Timely intervention can be associated with good visual outcome in such patients.