Outbreak of Ralstonia pickettii bacteraemia in patients with haematological malignancies and haematopoietic stem cell transplant recipients

The genus Ralstonia: The new kid on the block

The genus Ralstonia comprises of aerobic, gram-negative, oxidase positive, nonfermentative, largely environmental organisms. They are an emerging pathogen in the hospital setting and are increasingly associated with opportunistic infections and outbreaks. We hereby present a case series of six patients diagnosed with bacteraemia caused by Ralstonia spp. and a brief review of literature. These cases highlight that isolation of a nonfermenting gram-negative bacillus from blood culture of a patient admitted in critical care setting should not be ignored as mere contaminant. Clinicians and microbiologists need to work as a team to combat this novel bug.

Monoclonal outbreak of Ralstonia solanacearum catheter-related bloodstream infection associated with contaminated package of normal saline solution in a tertiary care hospital

Background/aim

Ralstonia solanacearum is a very rare cause of infection in humans. There is no described nosocomial outbreak due to R. solanacearum so far. We determined R. solanacearum as the source of catheter-related bloodstream infection (CRBSI) outbreak.

Materials and methods

This outbreak analysis was carried out in a 1000-bed tertiary care university hospital in Turkey. The outbreak analysis included hematology, oncology, nephrology, gastroenterology wards, emergency department, and intensive care units. The first case with R. solanacearum CRBSI was detected on May 20, 2019 and R. solanacearum was isolated in catheter blood cultures in 34 patients until October 3, 2019

Results

Standard outbreak analysis procedures were applied. Culture samples were taken from the fluids administered via catheters. The cultures did not yield any bacteria. As a result of the investigation in storage area, it was found that there were leaks, air bubbles, and water drops inside the packaging of saline solutions. R. solanacearum was yielded in the cultures obtained from the surface of saline bags and the inner sides of plastic packings. To validate our hypothesis, a clonal analysis was performed using arbitrarily primed-PCR method and Sanger sequencing of the 16S rRNA gene for identification among isolates. All R. solanacearum isolates were monoclonal and identical.

Conclusion

This is the first outbreak of R. solanacearum CRBSI described in a hospital setting. The source of the outbreak was a contamination in the surface of saline bags and the inner sides of plastic packings. Efficacy of an active surveillance system, accurate and rapid conduction of microbiological identification are essential for outbreak management.

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.

Outbreak of nonfermentative Gram-negative bacteria (Ralstonia pickettii and Stenotrophomonas maltophilia) in a hemodialysis center

We report a case series of seven patients with nonfermentative Gram-negative bacteria infections in a single dialysis center; four patients with Ralstonia pickettii and three patients with Stenotrophomonas maltophilia. Two of the seven patients were admitted to hospital for intravenous antibiotic treatment, while the rest were treated with oral antibiotics at home. Both the admitted patients had temporary vascular catheter infections from the aforementioned pathogens. We conclude that the outbreak is due to colonization of treated reverse osmosis water, presumably through contamination via polluted filters and compounded by the usage of reprocessed dialysers in the dialysis center. This is especially relevant because contaminated treated water is directly introduced into the blood compartment of the dialysers during reprocessing. In addition, there seems to be a propensity for both organisms to cause prolonged febrile reactions in patients with temporary vascular catheters, likely through the early development of biofilm. Intensification of general sterilization procedures, servicing and replacement of old decrepit components of the water treatment system and temporary cessation of dialyser reuse practice seem to have halted the outbreak. Due to the virulent nature and difficult resistant profile of nonfermentative Gram-negative bacteria, we strongly recommend meticulous vigilance in the surveillance of culture isolates in routine microbiological specimens from dialysis centers, especially if there is a senescent water treatment system and a practice of reprocessing dialysers.

Ralstonia pickettii bacteremia in hemodialysis patients: a report of two cases

Ralstonia pickettii is a low-virulence gram-negative bacillus that may be associated with infections related to health care and may cause bacteremia. Ralstonia pickettii bacteremia is uncommon but is related to the contamination of medical products, mainly in immunodepressed patients. We present two cases of patients on chronic hemodialysis with Ralstonia pickettii bacteremia linked to contamination of the dialysis water. Similar cases have been published with links to intravenous fluid administration, medication ampules, and the use of extracorporeal oxygenation membranes, among other factors. The detection of Ralstonia pickettii bacteremia should provoke suspicion and a search for contaminated medical products, fluids, and/or medications.

Ralstonia mannitolilytica infections in an oncologic day ward: description of a cluster among high-risk patients

BACKGROUND

Ralstonia spp, an environmental microorganism, has been occasionally associated with healthcare infections. The aim of this study was to investigate an outbreak caused by Ralstonia mannitolilytica in oncology patients.

METHODS

Case definition: Oncology outpatients attending a day ward, with positive blood and/or central venous catheter (CVC) culture for Ralstonia spp from September 2013 - June 2014. We analysed medical records, procedures and environmental samples. R. mannitolilytica was identified by 16S rRNA sequencing, and typed by Pulsed Field Gel Electrophoresis (PFGE); resistance to carbapenemes was investigated by phenotypic and molecular methods.

RESULTS

The patients (N = 22) had different malignancies and received different therapy; all had a CVC and 16 patients presented chills and/or fever. R. mannitolilytica was isolated from both blood and CVC (n = 12) or only blood (n = 6) or CVC tips (n = 4). The isolates had indistinguishable PFGE profile, and showed resistance to carbapenems. All the isolates were negative for carbapenemase genes while phenotypic tests suggests the presence of an AmpC β-lactamase activity,responsible for carbapenem resistance. All patients had had CVC flushed with saline to keep the venous access pervious or before receiving chemotherapy at various times before the onset of symptoms. After the first four cases occurred, the multi-dose saline bottles used for CVC flushing were replaced with single-dose vials; environmental samples were negative for R. mannitolilytica.

CONCLUSIONS

Although the source of R. mannitolilytica remains unidentified, CVC flushing with contaminated saline solution seems to be the most likely origin of R. mannitolilytica CVC colonization and subsequent infections. In order to prevent similar outbreaks we recommend removal of any CVC that is no longer necessary and the use of single-dose solutions for any parenteral treatment of oncology patients.

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.

Identification of silent prosthetic joint infection: preliminary report of a prospective controlled study

Purpose

We will test the hypothesis that ultrasound supported by polymerase chain reaction (PCR) could improve bacterial identification in non-infected prosthetic joint loosening. The aim was to detect bacterial species in non-infected prosthetic joint loosening using ultrasound and 16S rRNA gene sequencing.

Methods

A total of 16 patients (11 women and five men) aged 46–80 years (mean age 65.7) with diagnosed knee or hip implant loosening (mean implant survival of 102.1 months) were investigated. Bacterial culture and DNA sequencing were used to detect bacteria on the surface of failed implants removed during revision arthroplasty. The results of pre- and intraoperative culture and DNA sequencing were compared. Histopathological analysis was also performed.

Results

The number of positive cultures rises with a higher level of C-reactive protein (CRP). The results of the cultures from synovial fluid obtained through joint aspiration were consistent with sonicates from components of prostheses in 12 cases (75 %). Bacterial DNA was found in 90 % of patients with negative synovial fluid culture. PCR revealed two or more bacterial species, often of the same genus: Ralstonia pickettii, Pseudomonas spp., Brevibacterium spp., Lactobacillus spp., Propionibacterium spp. and Staphylococcus spp.These are micro-organisms present in the environment or on the human body and often associated with compromised immunity.

Conclusions

The ultrasound procedure followed by PCR and sequencing improve bacterial identification in silent prosthetic joint infection. The lack of clinical signs of infection and negative preoperative and intraoperative cultures do not exclude the presence of micro-organisms on the implants.